Patent Publication Number: US-2017373207-A1

Title: Solar cell module, method for manufacturing solar cell module, method for manufacturing electronic device having solar cell module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Application No. 10-2016-0081134, filed on Jun. 28, 2016, No. 10-2016-0081135, filed on Jun. 28, 2016, and No. 10-2016-0086336, filed on Jul. 7, 2016, the entire contents of all of which are incorporated by reference herein in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a solar cell module configured to produce electric power using light, a manufacturing method thereof, an electronic device having the solar cell module, and a manufacturing method thereof. 
     2. Background of the Invention 
     A solar cell is configured to convert light energy into an electric energy. In general, a solar cell includes a P type semiconductor and an N type semiconductor, and when the solar cell receives light, electric charges migrate to cause a potential difference. 
     A solar cell module refers to a module having a solar cell to produce electric power from light. A module refers to a constituent unit of a machine or a system and indicates an independent unit assembled to several electronic components or mechanical components to have a specific function. Thus, the solar cell module may be understood as indicating an independent unit having a solar cell and having a function of producing electric power from light. 
     A small solar cell module used as a driving power source of an electronic component generally has a structure including a printed circuit board (PCB), a solar cell, a protective layer formed on the entire surface of the solar cell, and an encapsulant layer formed between the solar cell and the protective layer. One or more solar cells are mounted on the PCB and electrically connected to an electrode connection part of the PCB. The solar cells are encapsulated by the protective layer and the encapsulant layer. 
     When a solar cell module is utilized in an electronic device, the electronic device may be driven using 1) indoor light supplied from a fluorescent light or an LED or 2) using natural light provided from the sun, without having to connect a separate power cable to the electronic device. Thus, compared with the related art electronic device which is necessarily to be connected to a separate power cable, the electronic device having a solar cell module is not limited in an installation place. 
     In spite of the advantages, however, the related art solar cell module has some problems to be solved. 
     First, component mounting is performed manually. The related art solar cell module has a component vulnerable to heat, and thus, a high temperature surface mount technology (SMT) cannot be applied during a process of manufacturing the solar cell module or during another process of using the solar cell module. Instead, in the related art solar cell module, components are mounted through a manual operation, and thus, it is difficult to secure process reliability and an operation pace is very slow. 
     Next, the related art solar cell module does not have sufficient light transmittance. Since the solar cell module produces electric power using light incident to a solar cell, high light transmittance is prerequisite for improvement of efficiency of the solar cell module. However, the related art solar cell module has a limitation in enhancement of light transmittance. 
     Thus, in order to solve the problem of the related art, a new approach to a structure of a solar cell module and a manufacturing method is required. 
     A solar cell module may be utilized as a sensor. The solar cell module utilized as a sensor may have a solar cell and is driven using electric power produced by the solar cell. Thus, the solar cell module utilized as a sensor may be used for the purpose of sensing a sensing target, without being limited to an installation place. 
     In spite of the advantages, however, the related art solar cell module has some problems to be solved. 
     In the related art, components such as a solar cell, a power source module, a communication module, and the like, are separately provided to form a single solar cell module to be utilized as a sensor, and the solar cell and other components are connected to each other by an electric cable. Thus, a connection structure of a cable for electrically connecting the solar cell and the other components is complicated and a large area is required to dispose the solar cell and the components. This leads to an increase in a size of a solar cell module, resultantly limiting an installation place of the solar cell module. 
     If the solar cell module, which is advantageously driven without being connected to a power cable, is limited in an installation place due to a size thereof, the strengths of the solar cell module cannot be sufficiently brought out, and thus, a design to reduce a size of the solar cell module is required. 
     SUMMARY OF THE INVENTION 
     Therefore, a first aspect of the detailed description is to provide a solar cell module having a configuration in which a component is automatically mounted. The present disclosure proposes a solar cell module having an encapsulant layer which is not melted or deformed during a process employing a high temperature surface-mount technology (SMT). 
     A second aspect of the detailed description is to provide a solar cell module in which an encapsulant layer has light transmittance higher than a multilayer structure of a polymer protective layer and an EVA encapsulant layer, and the encapsulant layer forms an outermost layer. 
     A third aspect of the detailed description is to provide a method for manufacturing a solar cell module having the encapsulant layer mentioned in the first aspect and the second aspect, and a method for manufacturing an electronic device having the solar cell module. 
     A fourth aspect of the detailed description is to provide a sensor module in which both surfaces of a printed circuit board (PCB) are utilized for mounting a solar cell, a circuit component, and the like, as an example of a solar cell module, and a manufacturing method. 
     A fifth aspect of the detailed description is to provide a structure of a solar cell module simpler than that of a related art. 
     A sixth aspect of the detailed description is to provide a solar cell module not limited in an installation place. 
     A seventh aspect of the detailed description is to provide a structure of a solar cell module smaller than that of a related art, without reducing an installation area of a solar cell required to secure an area to receive light. 
     In an aspect, a solar cell module may include an encapsulant layer formed of a material including silicon. The encapsulant layer may be formed to cover a solar cell or a primer layer to protect the solar cell. The silicon may have sufficient heat resistance even during a process employing a surface mount technology (SMT) at a high temperature of a maximum of 250° C. The primer layer may be formed between the solar cell and the encapsulant layer to strength bonding force between the solar cell and the encapsulant layer. 
     The solar cell module may include a solar cell mounted on a printed circuit board (PCB) and the encapsulant layer. The solar cell module may selectively include a dam layer forming edges of the encapsulant layer. The dam layer may be coupled to one surface of the PCB. The dam layer may serve to prevent a liquid encapsulant layer material from flowing to outside of the PCB during a process of manufacturing the solar cell module. 
     The liquid encapsulant layer material may include a curing agent for curing liquid silicon and a sunscreen to protect the solar cell from ultraviolet ray, as well as silicon. 
     The encapsulant layer may have high light transmittance in every light wavelength. The encapsulant layer may have light transmittance of 80% or greater with respect to light having a wavelength of 300 nm, light transmittance of 91% to 93% with respect to light having a wavelength of 350 nm, and light transmittance of 93% to 94% with respect to light having a wavelength of 400 nm to 700 nm. Also, the encapsulant layer has light transmittance of 91% to 94% with respect to visible light. 
     In order to protect the solar cell and have sufficient light transmittance, the encapsulant layer may have a thickness ranging from 200 to 1,000 The encapsulant layer may have a planar shape, may be uneven, or may have a dome shape. 
     In another aspect, a method for manufacturing a solar cell module may include: dispensing a liquid encapsulant layer material formed of a material including silicon and thermally curing the liquid encapsulant layer material. A method for manufacturing an electronic device may be classified into two embodiments depending on viscosity of an encapsulant layer material. 
     A manufacturing method of a first embodiment may include: preparing a printed circuit board (PCB) having an electrode connection part; performing a process of forming a dam layer on one surface of the PCB and a process of mounting at least one solar cell, regardless of order; dispensing a liquid encapsulant layer material formed of a material including silicon to cover the solar cell; thermally curing the encapsulant layer material to form an encapsulant layer; and cutting a solar cell module assembly formed by the preparing step and the thermally curing step into a unit size of a solar cell module. 
     In the first embodiment, the liquid encapsulant layer material may have viscosity of 10 Pa·s or less to have sufficient spreading characteristics. 
     A manufacturing method of a second embodiment may include: preparing a printed circuit board (PCB) having an electrode connection part; mounting at least one solar cell on one surface of the PCB; dispensing a liquid encapsulant layer material formed of a material including silicon to cover the solar cell; thermally curing the encapsulant layer material to form an encapsulant layer; and cutting a solar cell module assembly formed by the preparing step and the thermally curing step into a unit size of a solar cell module. 
     In the second embodiment, the liquid encapsulant layer material may have viscosity of 40 Pa·s or less not to flow to outside of the PCB. 
     Conditions for thermally curing the encapsulant layer material may be varied depending on types of silicon included in the encapsulant layer material. When heat is applied to the encapsulant layer material at about 130° C. to 170° C. for 30 to 150 minutes, the encapsulant layer material may be cured to form an encapsulant layer. 
     The solar cell module manufactured thusly is free of a problem that the encapsulant layer is melted or deformed during a process of employing a surface mount technology (SMT) of mounting a component by applying heat at a high temperature in a furnace, and thus, the solar cell module may be mounted on a main PCB of an electronic device through the SMT. Here, a temperature of heat applied to the solar cell module during the process employing the SMT is 200° C. to 250° C. 
     In the present disclosure, both surfaces of the PCB are utilized for mounting a component such that a solar cell, or the like, is stacked on a first surface of the PCB and a circuit component is mounted on a second surface of the PCB. Accordingly, an integrated sensor module may be realized. The first surface and the second surface face in mutually opposite directions, an electrode connection part may be formed on the first surface and a circuit wiring may be formed on the second surface. The solar cell and the encapsulant layer may be mounted on the first surface and a sensor part and the circuit component may be mounted on the second surface. 
     The first surface may be disposed to face a direction in which light is supplied, and the solar cell required to receive light may be mounted on the first surface and a circuit component not required to receive light may be mounted on the second surface. 
     The PCB may have a multilayer structure, and a circuit wiring of the PCB may include an inner layer wiring formed within the multilayer structure and an outer layer wiring formed on an outer surface of the multilayer structure. The inner layer wiring and the outer layer wiring may be connected to each other through the multilayer structure and may also be connected to the electrode connection part of the first surface. 
     The sensor part may be selectively mounted on the first surface or the second surface of the main PCB depending on whether the sensor part is required to be exposed to light or an external environment. An infrared sensor, an ultrasonic sensor, and an illumination sensor are required to be exposed to light or an external environment, so these sensors may be mounted on the first surface. A temperature sensor, a humidity sensor, and a gas sensor are not required to be exposed to light or an external environment, and thus, these sensors may be mounted on the second surface. 
     A battery may be coupled to the second surface, electrically connected to a circuit wiring, and store electric power produced by the solar cell. 
     The PCB may be protected by a case and a window. A coupling part may be provided in the case, and the coupling part may be configured to fixate the PCB to the inside of the case. 
     In order to achieve an object of the present disclosure, a solar cell module of the present disclosure may include a first PCB and a second PCB disposed in a multi-stage to face each other. The first PCB and the second PCB each may have a first surface and a second surface facing in mutually opposite directions. A solar cell may be stacked on the first surface of the first PCB so as to be exposed to light, an electric element may be stacked on the second PCB, and the first PCB and the second PCB may be electrically connected by a connection part. 
     The solar cell of the first PCB and the electric element of the second PCB may be electrically connected by the connection part, and electric power produced by the solar cell may be used to drive the electric element. 
     The connection part may be formed by a flexible printed circuit (FPC) or at least one connector. When the connection part is formed by a connector, the connector may be installed between the first PCB and the second PCB to support the first PCB. 
     The solar cell module may include the first PCB or a sensor part mounted on the first PCB. 
     The solar cell module may include: a case configured to accommodate the first PCB and the second PCB; and a window formed of a transparent material, covering the solar cell accommodated in the case, and coupled to the case. 
     The solar cell module may include a sensor part installed on the first surface of the first PCB, and the sensor part may include at least one of an infrared sensor, an ultrasonic sensor, and an illumination sensor and may be disposed to be visually exposed through the window. 
     The solar cell module may include a sensor part installed on the second PCB, the sensor part may include at least one of a temperature sensor, a humidity sensor, and a gas sensor, and a vent hole may be formed in the case. 
     A coupling part may be formed in the case to fixate the first PCB and the second PCB at different levels. 
     The solar cell module may include a power conversion circuit, a battery, or a communication unit, and the power conversion circuit, the battery, and the communication unit may be mounted on the first PCB or the second PCB. The power conversion circuit and the battery may be mounted on the second surface of the first PCB, and the communication unit may be mounted on the first PCB. 
     Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from the detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate example embodiments and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIGS. 1A and 1B  are perspective views of a solar cell module of the present disclosure viewed in different directions. 
         FIG. 2  is a cross-sectional view of a solar cell module of a first embodiment. 
         FIG. 3  is a cross-sectional view of a solar cell module according to a modification of the first embodiment. 
         FIG. 4  is a cross-sectional view of a solar cell module according to another modification of the first embodiment. 
         FIG. 5  is a cross-sectional view of a solar cell module of a second embodiment. 
         FIG. 6  is a cross-sectional view of a solar cell module according to a modification of the second embodiment. 
         FIG. 7  is a cross-sectional view of a solar cell module according to another modification of the second embodiment. 
         FIG. 8  is a graph illustrating light transmittance percentage of an encapsulant layer formed of a material including silicon by wavelengths. 
         FIG. 9  is a flow chart illustrating a process of manufacturing a solar cell module of the first embodiment. 
         FIGS. 10A to 10G  are conceptual views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 9 . 
         FIGS. 11A to 11H  are cross-sectional views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 9 . 
         FIG. 12  is a flow chart illustrating a process of manufacturing a solar cell module of a second embodiment. 
         FIGS. 13A to 13E  are conceptual views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 12 . 
         FIGS. 14A to 14F  are cross-sectional views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 12 . 
         FIG. 15  is a flow chart illustrating a method of manufacturing an electronic device having a solar cell module. 
         FIGS. 16A and 16B  are perspective views of a first embodiment of an integrated sensor module including a solar cell and a circuit component, viewed in different directions. 
         FIG. 17  is a cross-sectional view of a sensor module including a case and a window. 
         FIGS. 18A and 18B  are perspective views of a second embodiment of an integrated sensor module including a solar cell and a circuit component, viewed in different directions. 
         FIG. 19  is a cross-sectional view of a sensor module including a case and a window. 
         FIG. 20  is a flow chart illustrating a method for manufacturing a sensor module. 
         FIGS. 21A to 21C  are cross-sectional views illustrating a process of manufacturing a sensor module according to the method of manufacturing a sensor module illustrated in  FIG. 20 . 
         FIG. 22  is a flow chart illustrating another method of manufacturing a sensor module. 
         FIGS. 23A to 23C  are cross-sectional views illustrating a process of manufacturing a sensor module according to the method of manufacturing a sensor module illustrated in  FIG. 22 . 
         FIG. 24  is a perspective view illustrating a sensor module of the present disclosure. 
         FIG. 25  is a perspective view illustrating components accommodated within a case. 
         FIG. 26  is a cross-sectional view of a sensor module. 
         FIGS. 27A to 27C  are conceptual views illustrating an example of a method for manufacturing a sensor module. 
         FIGS. 28A to 28E  are conceptual views illustrating another example of a method for manufacturing a sensor module. 
         FIG. 29  is a perspective view illustrating another embodiment of a sensor module. 
         FIG. 30  is a perspective view illustrating another embodiment of a sensor module. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Description will now be given in detail of the example embodiments, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated. 
       FIGS. 1A and 1B  are perspective views of a solar cell module of the present disclosure viewed in different directions. 
     A solar cell module  100  refers to a module having a solar cell  120  to produce electric power from light. A module refers to a constituent unit of a machine or a system and represents an independent unit assembled to several electronic components or mechanical components to have a specific function. Thus, the solar cell module  100  may be understood as indicating an independent unit having a solar cell  120  and having a function of producing electric power from light. 
     The solar cell module  100  includes a printed circuit board (PCB)  110 , a solar cell  120 , an encapsulant layer  130 , a dam layer  140 , output terminals  151  and  152 , and an electrode connection part  160 . Hereinafter, the components will be described in detail. 
     The PCB  110  supports the entirety of the solar cell module  100  and is electrically connected to the solar cell  120 . The PCB  110  is formed of an insulating material. An electrode part of the solar cell  120  and the electrode connection part  160  of the PCB  110  are electrically connected, while a region other than a region in which the electrode connection part  160  is formed is electrically insulated by an insulating material. 
     The PCB  110  has a first surface and a second surface which face in the opposite directions. The first surface may be referred to as a front surface or an upper surface, and the second surface may be referred to as a rear surface or a lower surface. The electrode connection part  160  electrically connected to the solar cell  120  is exposed to the first surface, and output terminals  151  and  152  outputting power collected from the solar cell  120  are exposed to the second surface. However, alternatively, the output terminals  151  and  152  may be exposed to the first surface of the PCB  110 , unlike those illustrated in  FIG. 1B . 
     The electrode connection part  160  is configured to connect a plurality of solar cells  121 ,  122 ,  123 , and  124  in series. For example, a plurality of electrode connection parts  162 ,  163 , and  164  are disposed between the solar cells  121 ,  122 ,  123 , and  124 , and each of the electrode connection units  162 ,  163 , and  164  electrically connect two adjacent solar cells  121  and  122 ,  122  and  123 , and  123  and  124 . The electrode connection unit  160  is electrically connected to the output terminals  151  and  152 . 
     The solar cell  120  is mounted on the PCB  110  and an electrode part of the solar cell  120  is electrically connected to the electrode connection unit  160  of the PCB  110 . The solar cell  120  may be mounted on a first surface of the PCB  110  partially converts the electrode connection unit  160  formed on the first surface of the PCB  110 . An electrical connection structure of the electrode part of the solar cell  120  and the electrode connection part  160  of the PCB  110  will be described hereinafter with reference to  FIGS. 2 to 7 . 
     One solar cell module may have a plurality of solar cells  121 ,  122 ,  123 , and  124 . The plurality of solar cells  121 ,  122 ,  123 , and  124  may be dispose to be spaced apart from each other on the same planar surface. The plurality of solar cells  121 ,  122 ,  123 , and  124  may be connected in series to each other by the electrode connection parts  162 ,  163 , and  164 . In  FIG. 1 , it is illustrated that four solar cells  121 ,  122 ,  123 , and  124  are provided in the single solar cell module  100 , but the number and disposition of the solar cells  121 ,  122 ,  123 , and  124  may be varied depending on a design of the solar cell module  100 . 
     The solar cell  120  is configured to convert light energy into electrical energy. In general, the solar cell  120  is formed of a P type semiconductor and an N type semiconductor and when light is applied to the solar cell  120 , electric charges migrate to generate a potential difference. 
     A structure in which two electrodes of each solar cell  120  are all formed on the opposite surface of a light receiving surface (or a light collecting surface) of the solar cell  120  may be termed a back contact structure. It can be seen that two electrodes of each of the solar cells  121 ,  122 ,  123 , and  124  are all formed on the opposite surface of the light receiving surface in that the solar cells  121 ,  122 ,  123 , and  124  illustrated in  FIGS. 1A and 1B  are connected in series to each other by the electrode connection parts  162 ,  163 , and  164 . Thus, the solar cells  121 ,  122 ,  123 , and  124  illustrated in  FIGS. 1A and 1B  are classified as solar cells having a back contact structure. 
     In contrast, a structure in which one electrode is formed on each of a light receiving surface and an opposite surface of a solar cell is classified as a general structure. In the general structure, an electrode of a certain solar cell and an electrode of another solar cell adjacent to the certain solar cell (the two electrodes have the opposite polarities) are connected in series by a separate conductor. 
     The encapsulant layer  130  covers the solar cell  120  to protect the solar cell  120  from external impact, moisture, and the like. In cases where the solar cells  121 ,  122 ,  123 , and  124  are provided in plurality, the encapsulant layer  130  may cover all of the plurality of solar cells  121 ,  122 ,  123 , and  124 . 
     The encapsulant layer  130  is transparent. Since the solar cell  120  produces electric power using light, an amount of light transmitted to the solar cell  120  may be increased as transparency of the encapsulant layer  130  is increased. 
     A primer layer may be formed between the encapsulant layer  130  and the solar cell  120  to bond the encapsulant layer  130  to the solar cell  120 . However, in cases where the encapsulant layer  130  is adhesive, the encapsulant layer  130  may not be separated from the solar cell  120 , even without the primer layer. Thus, the primer layer is optional, and not essential to the solar cell module  100 . 
     In order to solve the problem of the related art solar cell module, the encapsulant layer  130  of the present disclosure is formed of a material including silicon. 
     The material including silicon refers to a material including any other material in addition to silicon. Here, the other material includes, for example, a curing agent for curing liquid silicon during a process of manufacturing the solar cell module  100 , a sunscreen for blocking ultraviolet ray incident to the solar cell, and an adhesive providing adhesion to the encapsulant layer. In the present disclosure, types of the curing agent, sunscreen, and adhesive are not particularly limited. 
     Silicon has high heat resistance, relative to a polymer protective layer and an ethylene-vinyl acetate copolymer (EVA) adhesive layer. Thus, the solar cell module  100  having the encapsulant layer  130  formed of a material including silicon does not cause melting or deformation of the encapsulant layer  130  even in a process of applying a high temperature surface-mount technology (SMT). A temperature of the process of applying the SMT is a maximum of 250° C. and silicon has sufficient heat resistance at the temperature. 
     Thus, according to the present disclosure having the encapsulant layer  130  formed of a material including silicon, it is possible to mount a circuit component by applying a high temperature SMT to the PCB  110  of the solar cell module  100 , as well as mounting the solar cell module  100  on a main PCB (a separate component on which the solar cell module  100  is to be mounted) by applying the high temperature SMT. 
     The solar cell module  100  of the present disclosure has an outermost layer formed of the silicon encapsulant layer  130  on the solar cell  120 . Unlike the related art solar cell module having the encapsulant layer and the protective layer, the silicon encapsulant layer  130  also has a function of a protective layer, and thus, the solar cell module  100  of the present disclosure does not require a separate protective layer on the silicon encapsulant layer  130 . 
     Compared with a case in which an encapsulant layer and a protective layer are separately provided, the outermost layer formed only on the silicon encapsulant layer  130  may realize a more reduced thickness. Thus, compared with the related art, in the present disclosure, an amount of light reaching the solar cell  120  may be increased, and thus, efficiency of the solar cell module  100  may be enhanced. Such an effect relates to light transmittance of the silicon encapsulant layer  130  as described hereinafter with reference to  FIG. 8 . 
     The encapsulant layer  130  preferably has a thickness ranging from 200 to 1,000 μm. If the thickness of the encapsulant layer  130  is smaller than 200 μm, it is difficult to sufficiently protect the solar cell  120 . Thus, in order to protect the solar cell  120 , the encapsulant layer  130  has a thickness of 200 μm or greater. Conversely, if the thickness of the encapsulant layer  130  exceeds 1,000 μm, light transmittance is degraded to lower efficiency of the solar cell module  100 . Thus, preferably, the thickness of the encapsulant layer  130  does not exceed 1,000 μm. 
     The dam layer  140  is coupled to one surface of the PCB  110 . One surface of the PCB  110  indicates a surface on which the solar cell  120  and the encapsulant layer  130  are formed. As mentioned above, opposing surfaces of the PCB  110  are divided into the first surface and the second surface and the solar cell  120  and the encapsulant layer  130  are formed on the first surface. According to the descriptions, the dam layer  140  is coupled to the first surface of the PCB  110 . 
     The dam layer  140  is formed on the edges of the encapsulant layer  130 . The dam layer  140  supports the edges of the encapsulant layer  130  and protects the solar cell  120  and the edges of the encapsulant layer  130 . 
     The dam layer  140  serves to prevent a liquid encapsulate layer material from flowing to an outer side of the PCB  110  during a process of manufacturing the solar cell module  100 . Thus, when the liquid encapsulant layer material has sufficiently high viscosity, the dam layer  140  is not required and, and in this case, the dam layer  140  may be not be essential but optional. 
     Hereinafter, various structures of the solar cell module will be described. Cross-sectional views of the solar cell module illustrated in  FIGS. 2 to 7  are cross-sectional views of the solar cell module, taken along line A-A of  FIG. 1 , and viewed from one side. 
       FIG. 2  is a cross-sectional view of a solar cell module  200  of a first embodiment. 
     A PCB  210  includes an electrode connection part  260  and the electrode connection parts  260  are exposed to a first surface of the PCB  210 . The electrode connection parts  260  are disposed to be spaced apart from each other and connect solar cells  221 ,  222 ,  223 , and  224  in series. The solar cells  221 ,  222 ,  223 , and  224  have two electrodes  221   a  and  221   b ,  222   a  and  222   b ,  223   a  and  223   b , and  224   a  and  224   b , having the opposite polarities, respectively. 
     Referring to  FIG. 2 , when the solar cell module  200  includes four solar cells  221 ,  222 ,  223 , and  224 , five electrode connection parts  261 ,  262 ,  263 ,  264 , and  265  are formed to connect four solar cells  221 ,  222 ,  223 , and  224  in series, and among them, three electrode connection parts  262 ,  263 , and  264  are disposed between two solar cells  221  and  222 , between solar cells  222  and  223 , and between solar cells  223  and  224 . For the purposes of description, four solar cells  221 ,  222 ,  223 , and  224  are referred to as first to fourth solar cells  221 ,  222 ,  223 , and  224 , and five electrode connection parts  261 ,  262 ,  263 ,  264 , and  265  may be referred to as first to fifth electrode connection parts  261 ,  262 ,  263 ,  264 , and  265 . 
     The first solar cell  221  has electrode parts  221   a  and  221   b  including a negative electrode  221   a  and a positive electrode  221   b , and the negative electrode  221   a  and the positive electrode  221   b  are disposed to be spaced apart from each other on the opposite surface of a light receiving surface. When the first solar cell  221  is mounted on the PCB  210 , the negative electrode  221   a  is connected to the first electrode connection part  261  and the positive electrode  221   b  is connected to the second electrode connection part  262 . 
     The second solar cell  222  has electrode parts  222   a  and  222   b  including a negative electrode  222   a  and a positive electrode  222   b , and the negative electrode  222   a  and the positive electrode  222   b  are disposed to be spaced apart from each other on the opposite surface of a light receiving surface. When the second solar cell  222  is mounted on the PCB  210 , the negative electrode  222   a  is connected to the second electrode connection part  262  and the positive electrode  222   b  is connected to the third electrode connection part  263 . 
     The third solar cell  223  has electrode parts  223   a  and  223   b  including a negative electrode  223   a  and a positive electrode  223   b , and the negative electrode  223   a  and the positive electrode  223   b  are disposed to be spaced apart from each other on the opposite surface of a light receiving surface. When the third solar cell  223  is mounted on the PCB  210 , the negative electrode  223   a  is connected to the third electrode connection part  263  and the positive electrode  223   b  is connected to the fourth electrode connection part  264 . 
     The fourth solar cell  224  has electrode parts  224   a  and  224   b  including a negative electrode  224   a  and a positive electrode  224   b , and the negative electrode  224   a  and the positive electrode  224   b  are disposed to be spaced apart from each other on the opposite surface of a light receiving surface. When the fourth solar cell  224  is mounted on the PCB  210 , the negative electrode  224   a  is connected to the fourth electrode connection part  264  and the positive electrode  224   b  is connected to the fifth electrode connection part  265 . 
     The electrode connection parts  261 ,  262 ,  263 ,  264 , and  265  and output terminals  251  and  252  formed on the second surface of the PCB  210  are electrically connected to each other. A structure such as a through hole or a via hole may be formed on the PCB  210 , and the electrode connection parts  261  and  265  at both ends are connected to the output terminals  251  and  252  by a wiring passing through the through hole or the via hole. For example, the first electrode connection part  261  is connected to the output terminal  251  on one side and the fifth electrode connection part  265  is connected to the output terminal  252  on the other side. The wiring excluding the electrode connection parts may be formed within the PCB  210 . 
     The plurality of solar cells  221 ,  222 ,  223 , and  224  are mounted on the first surface of the PCB  210 , and an encapsulant layer  230  is disposed on the plurality of solar cells  221 ,  222 ,  223 , and  224  to protect the plurality of solar cells  221 ,  222 ,  223 , and  224 . An upper surface of the encapsulant layer  230  illustrated in  FIG. 2  has a planar structure. 
     A primer layer  280  for strengthening adhesion may be provided between the solar cell  220  and the encapsulant layer  230 . The primer layer  280  is configured to bond the encapsulant layer  230  to the solar cell  220 . However, as mentioned above, the primer layer  280  is not essential to the solar cell module  200 . 
     A dam layer  240  is provided on the edges of the PCB  210 . The dam layer  240  has a height higher than a side surface of the encapsulant layer  230  to define a region of the encapsulant layer  230 . An outer boundary of the solar cell module  200  may be formed by the dam layer  240 . 
       FIG. 3  is a cross-sectional view of a solar cell module  300  according to a modification of the first embodiment. 
     The solar cell module  300  illustrated in  FIG. 3  has the same structure as that of the solar cell module  200  illustrated in  FIG. 2 , except a structure of an encapsulant layer  330 . Compared with the encapsulant layer  230  of the solar cell module  200  illustrated in  FIG. 2 , having a planar structure, the encapsulant layer  330  of the solar cell module  300  illustrated in  FIG. 3  partially has a concavo-convex portion. 
     The concavo-convex portion of the encapsulant layer  330  is formed on the edges of the solar cells  321 ,  322 ,  323 , and  324 . For example, the concavo-convex portion may be formed at a left end portion and a right end portion of the solar cell  320  and between the solar cells  321  and  322 , between the solar cells  322  and  323 , and between the solar cells  323  and  324 . 
     When the encapsulant layer  330  has the concavo-convex portion, a thickness of the encapsulant layer  330  is thinner than the planar encapsulant layer  230  of  FIG. 2 , and thus, light transmittance of the encapsulant layer  330  is increased. Thus, an amount of light incident to the solar cell  320  may be increased and efficiency of the solar cell module  300  may be increased. 
     Components not described in  FIG. 3  may be referred to the descriptions of  FIG. 2 . Reference numeral  310  not described in  FIG. 3  denotes a PCB,  321  to  324  denote first to fourth solar cells,  340  denotes a dam layer, and  351  and  352  denote output terminals. Also, reference numeral  360  denotes an electrode connection part,  361  to  365  denote first to fifth electrode connection parts, and  380  denotes a primer layer. 
       FIG. 4  is a cross-sectional view of a solar cell module  400  according to another modification of the first embodiment. 
     The solar cell module  400  illustrated in  FIG. 4  has the same structure as that of the solar cell module  200  illustrated in  FIG. 2 , except a structure of an encapsulant layer  430 . Compared with the encapsulant layer  230  of the solar cell module  200  illustrated in  FIG. 2 , having a planar structure, the encapsulant layer  430  of the solar cell module  400  illustrated in  FIG. 4  partially has a circular shape, like a dome shape, rather than a planar structure. 
     A thickness of the encapsulant layer  430  is most thick in a position facing the middle portion of each of the solar cells  421 ,  422 ,  423 , and  424  and is reduced toward left and right ends of each of the solar cells  421 ,  422 ,  423 , and  424 . The thickness of the encapsulant layer  430  is most thin at left and right ends of each of the solar cells  421 ,  422 ,  423 , and  424  and between two solar cells  421  and  422 , between two solar cells  422  and  423 , and between two solar cells  423  and  424 . 
     When the thickness of the encapsulant layer  430  is increased, light transmittance of the encapsulant layer  430  may be slightly lowered, but the solar cell  420  may be more stably protected from a physical external force. A physical external force applied to the solar cell  420  is highly likely to concentrate largely on a middle portion, rather than on left and right ends of each of the solar cells  421 ,  422 ,  423 , and  424 . Thus, when the thickness of the encapsulant layer  430  is thick in the position facing a middle portion of each of the solar cells  421 ,  422 ,  423 , and  424 , the solar cells  421 ,  422 ,  423 , and  424  may be sufficiently protected. Also, when the thickness of the encapsulant layer  430  is reduced at left and right ends of each of the solar cells  421 ,  422 ,  423 , and  424 , a degradation of light transmittance may be slightly restrained. 
     Components not described in  FIG. 4  may be referred to the descriptions of  FIG. 2 . In  FIG. 4 , reference numeral  410  not described in  FIG. 3  denotes a PCB,  421  to  424  denote first to fourth solar cells,  440  denotes a dam layer, and  451  and  452  denote output terminals. Also, reference numeral  460  denotes an electrode connection part,  461  to  465  denote first to fifth electrode connection parts, and  480  denotes a primer layer. 
       FIG. 5  is a cross-sectional view of a solar cell module  500  of a second embodiment. 
     The solar cell module  500  illustrated in  FIG. 5  has the same structure as that of the solar cell module  200  illustrated in  FIG. 2 , except that the solar cell module of  FIG. 5  has dam layers  240 ,  340 , and  440  (please refer to  FIGS. 2 to 4 ). The dam layers serve to prevent a liquid encapsulant layer material from flowing to an outer of a PCB during a process of curing the liquid encapsulant layer material to form an encapsulant layer. 
     If the liquid encapsulant layer material has sufficiently high viscosity, it may not flow to the outside of the PCB  510 . Thus, in cases where the encapsulant layer  530  is formed of an encapsulant layer material with sufficiently high viscosity, the solar cell module  500  may be manufactured without a dam layer. The sufficiently high viscosity will be described hereinafter. 
     Without the dam layer at the edges of the encapsulant layer  530 , a size of the solar cell module  500  may be reduced even it has the solar cells  521 ,  522 ,  523 , and  524  having the same area. For example, the solar cell module  500  illustrated in  FIG. 5  is smaller than the solar cell module  200  illustrated in  FIG. 2  by a width of the dam layer  240 . 
     Efficiency of the solar cell module  500  is determined on the basis of an overall size of the solar cell module  500 . Thus, when the solar cell module  500  has the solar cells  521 ,  522 ,  523 , and  524  having the same area, the solar cell module  500  has higher efficiency as a size thereof is reduced. Thus, when the size of the solar cell module  500  is reduced by the width of the dam layer, efficiency of the solar cell module  500  may be enhanced by the corresponding ratio. 
     Components not described in  FIG. 5  may be referred to the descriptions of  FIG. 2 . In  FIGS. 5, 521 to 524  denote first to fourth solar cells and  551  and  552  denote output terminals. Also, reference numeral  560  denotes an electrode connection part,  561  to  565  denote first to fifth electrode connection parts, and  580  denotes a primer layer. 
       FIG. 6  is a cross-sectional view of a solar cell module  500  according to a modification of the second embodiment. 
     The solar cell module  600  illustrated in  FIG. 6  has the same structure as that of the solar cell module  500  illustrated in  FIG. 5 , except a structure of an encapsulant layer  630 . Compared with the encapsulant layer  530  of the solar cell module  500  illustrated in  FIG. 5 , having the planar structure, the encapsulant layer  630  of the solar cell module  600  illustrated in  FIG. 6  partially has a concavo-convex portion overall. 
     The concavo-convex portion of the encapsulant layer  630  is formed at edges of each of the solar cells  621 ,  622 ,  623 , and  624 . For example, a concavo-convex portion may be formed at a left end portion and a right end portion of each of the solar cells  621 ,  622 ,  623 , and  624 , and between two solar cells  621  and  622  and two solar cells  622  and  623 , and between two solar cells  623  and  624 . 
     When the encapsulant layer  630  has the concavo-convex portion, a thickness of the encapsulant layer  630  is thinner than a planar encapsulant layer, and thus, light transmittance of the encapsulant layer  630  is increased. Thus, an amount of light incident to the solar cell  620  may be increased and efficiency of the solar cell module  600  may be increased. 
     Components not described in  FIG. 6  may be referred to the descriptions of  FIG. 5 . Reference numeral  610  not described in  FIG. 6  denotes a PCB,  621  to  624  denote first to fourth solar cells, and  651  and  652  denote output terminals. Also, reference numeral  660  denotes an electrode connection part,  661  to  665  denote first to fifth electrode connection parts, and  680  denotes a primer layer. 
       FIG. 7  is a cross-sectional view of a solar cell module  700  according to another modification of the second embodiment. 
     The solar cell module  700  illustrated in  FIG. 7  has the same structure as that of the solar cell module  500  illustrated in  FIG. 5 , except a structure of an encapsulant layer  730 . Compared with the encapsulant layer  530  of the solar cell module  500  illustrated in  FIG. 5 , having a planar structure, the encapsulant layer  730  of the solar cell module  700  illustrated in  FIG. 4  partially has a circular shape, like a dome shape, rather than a planar structure. 
     A thickness of the encapsulant layer  730  is most thick in a position facing the middle portion of each of the solar cells  721 ,  722 ,  723 , and  724  and is reduced toward left and right ends of each of the solar cells  721 ,  722 ,  723 , and  724 . The thickness of the encapsulant layer  730  is most thin at left and right ends of each of the solar cells  721 ,  722 ,  723 , and  724  and between two solar cells  721  and  722 , between two solar cells  722  and  723 , and between two solar cells  723  and  724 . 
     In a region where the thickness of the encapsulant layer  730  is large, light transmittance of the encapsulant layer  730  may be slightly lowered but the solar cell may be more stably protected from a physical external force. 
     Components not described in  FIG. 7  may be referred to the descriptions of  FIG. 5 . In  FIG. 7 , reference numeral  710  not described in  FIG. 7  denotes a PCB,  721  to  724  denote first to fourth solar cells,  751  and  752  denote output terminals. Also, reference numeral  760  denotes an electrode connection part,  761  to  765  denote first to fifth electrode connection parts, and  780  denotes a primer layer. 
       FIG. 8  is a graph illustrating light transmittance percentage of an encapsulant layer formed of a material including silicon by wavelengths. 
     In the graph, the horizontal axis represents wavelength (nm) of light incident to a solar cell, and the vertical axis represents light transmittance (%) of encapsulant layer. 
     A solar cell module is configured to produce electric power using light incident to a solar cell. Thus, as light transmittance of an encapsulant layer covering the solar cell is higher, efficiency of the solar cell module is higher. However, UV light having strong energy, relative to visible light or infrared light, may damage the solar cell. For this reason, the encapsulant layer may include a sunscreen. 
     Referring to the graph of  FIG. 8 , light transmittance of the encapsulant layer is gradually increased as a wavelength of light is increased, and is relatively uniform from a wavelength of about 600 nm. 
     The encapsulant layer formed of silicon has light transmittance of 80% or greater with respect to light having a wavelength of 300 nm, and more strictly, has light transmittance of 85% or greater. Compared with a polymer protective layer and an EVA bonding layer having light transmittance lower than 80% with respect to light having a wavelength of 300 nm, light transmittance of the encapsulant layer formed of silicon is high. 
     Also, the encapsulant layer formed of a material including silicon has light transmittance of 91% to 93% with respect to light having a wavelength of 350 nm. Compared with light transmittance of the polymer protective layer and the EVA bonding layer having light transmittance lower than 91% with respect to light having a wavelength of 350 nm, the light transmittance of the encapsulant layer formed of a material including silicon is high. 
     Also, the encapsulant layer formed of a material including silicon has light transmittance of 93% to 94% with respect to light having a wavelength of 400 nm to 780 nm. Compared with the polymer protective layer and the EVA bonding layer having light transmittance lower than 91% with respect to light having a wavelength of 400 nm to 780 nm, light transmittance of the encapsulant layer formed of a material including silicon is high. 
     Also, the encapsulant layer formed of a material including silicon has light transmittance of 91% to 94% with respect to visible light. A wavelength range in which a human being may feel or perceive light with his eyes may be slightly different by persons so it may be difficult to clearly determine a range of visible light, but light having a wavelength of about 380 nm to 800 nm corresponds to visible light. Compared with the polymer protective layer and the EVA bonding layer having light transmittance lower than 91% with respect to visible light, light transmittance of the encapsulant layer formed of a material including silicon is high. 
     To sum up, the encapsulant layer formed of a material including silicon has light transmittance higher than that of the polymer protective layer and the EVA bonding layer in every wavelength. Thus, since the encapsulant layer increases an amount of light incident to the solar cell, relative to the polymer protective layer and the EVA bonding layer, a solar cell module having efficiency higher than that of the related art may be realized. 
     Hereinafter a method for manufacturing the solar cell module described above will be described. 
       FIG. 9  is a flow chart illustrating a process of manufacturing solar cell modules ( 200 ,  300 , and  400  of  FIGS. 2 to 4 ) of the first embodiment.  FIGS. 10A to 10G  are conceptual views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 9 .  FIGS. 11A to 11H  are cross-sectional views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 9 . 
       FIGS. 10A to 10G  illustrate a process of manufacturing a plurality of solar cell modules, and  FIGS. 11A to 11H  illustrate a process of manufacturing one of a plurality of solar cell modules. 
     Referring to  FIG. 9 , in order to manufacture a solar cell module, first, a PCB  810  having an electrode connection part is prepared (S 110 ).  FIGS. 10A and 11A  correspond to step S 110  of  FIG. 9 . 
     Referring to  FIG. 10A , the PCB  810  is divided into a plurality of regions, and an electrode connection part  860  is formed in each of the regions. The electrode connection part  860  may have been solder-processed. Wirings other than the electrode connection part  860  may be formed within the PCB  810 . 
     The electrode connection part  860  includes a first electrode connection part  861  to a fifth electrode connection part  865 . The first electrode connection part  861  to the fifth electrode connection part  865  are disposed to be spaced apart from each other. The number of the electrode connection parts  861 ,  862 ,  863 ,  864 , and  865  may be varied depending on a design of a solar cell module. 
     In  FIG. 10A , a first surface of the PCB  810  is illustrated, and a second surface of the PCB  810  is illustrated in  FIG. 11A . Referring to  FIG. 11A , the electrode connection part  860  is exposed to the first surface of the PCB  810 , and output terminals  851  and  852  are formed on the second surface of the PCB  810 . As illustrated in  FIG. 11A , the output terminals  851  and  852  may be formed on one side and the other side of the second surface. Alternatively, the output terminals  851  and  852  may be formed abreast on the second surface, and both the output terminals  851  and  852  may be formed on the first surface or the output terminals  851  and  852  may respectively be formed on the first surface and the second surface. 
     Referring back to  FIG. 9 , a dam layer is formed on one surface of the PCB. One surface of the PCB refers to a first surface on which a solar cell is to be mounted.  FIGS. 10B, 10C, and 11B  correspond to step S 120  of  FIG. 9 . 
     Referring to  FIG. 10B , the dam layer is formed by attaching a unit grid assembly  840 ′ on the first surface of the PCB  810 . A size of the unit grid assembly  850 ′ corresponds to the PCB  810 , and each of unit grids has a size of corresponding to a unit size of a solar cell module. A hole is formed in each of the unit grids and each of the unit grids forms an edge of the hole. Also, a plurality of unit grids gather to form a single assembly  840 ′. 
       FIG. 100  is a modification of  FIG. 10B . Referring to  FIG. 100 , unit grids of a unit grid assembly  840 ″ are formed to have a size covering each solar cell to be mounted on the PCB  810 . Each unit grid is formed at every edge of a solar cell. A boundary is formed by the unit grid assembly  840 ″ between solar cells. 
     The unit grid assemblies  840 ′ and  840 ″ may be bonded to the PCB  810  by an adhesive. 
     The unit grid assemblies  840 ′ and  840 ″ may be formed of the same material as that of the PCB  810 . For example, the unit grid assemblies  840 ′ and  840 ″ and the PCB  810  may be formed of a glass epoxy called an FR4 (frame retardant). Also, the unit grid assemblies  840 ′ and  840 ″ and the PCB  810  may be formed of at least one of various materials such as ceramics, a metal, and the like. 
     Referring to  FIG. 11B , as the unit grid assembly is bonded to a first surface of the PCB  810 , a dam layer  840  is formed. The unit grid is formed at an edge of the PCB  810 . 
     Since a hole is formed in the unit grid, the first surface of the PCB  810  on which a solar cell is to be mounted is partially exposed through the unit grid. The region exposed through the unit grid may be referred to as an exposed region of the PCB  810 . 
     Referring back to  FIG. 9 , at least one solar cell is mounted in each exposed region of the PCB exposed through unit grids (S 130 ). A solar cell is mounted on the first surface of the PCB, and the number of solar cells may be varied depending on a design of a solar cell module.  FIGS. 10D and 11C  correspond to step S 130  of  FIG. 9 . 
     Referring to  FIG. 10D , four solar cells  821 ,  822 ,  823 , and  824  are respectively mounted in exposed regions of the PCB  810  exposed through unit grids. Referring to  FIG. 11C , the solar cells  821 ,  822 ,  823 , and  824  are disposed to be spaced apart from each other. Electrode connection parts  860  formed on the PCB  810  and electrode parts  821   a ,  821   b ,  822   a ,  822   b ,  823   a ,  823   b ,  824   a , and  824   b  of the solar cell  820  are physically in contact with each other. The step of forming the dam layer  840  and the step of mounting the solar cell  820  may be reversed in order. 
     Referring back to  FIG. 9 , a primer layer is formed on the solar cell (S 140 ). The primer layer serves to bond an encapsulant layer to the solar cell.  FIG. 11D  corresponds to step S 140  of  FIG. 9 . 
     Referring to  FIG. 11D , a primer layer  880  is formed on the solar cells  821 ,  822 ,  823 , and  824 . In step S 140  of forming the primer layer  880 , a primer material is sprayed to the solar cells  821 ,  822 ,  823 , and  824  and thermally cured. Here, thermally curing the primer material is performed such that the primer material is heat-treated at temperatures 90° C. to 110° C. for 20 to 40 minutes. 
     However, in the solar cell module, the primer layer  880  is not essential, and thus, step S 140  of forming a primer layer is not essential in the method of manufacturing a solar cell module. Thus, step S 140  of forming a primer layer may be omitted and step S 150  of dispensing an encapsulant layer material may be performed immediately after step S 130  of mounting a solar cell. 
     Referring back to  FIG. 9 , a liquid encapsulant layer material is dispensed (S 150 ) after step S 130  of mounting a solar cell or after step S 140  of forming a primer layer. Without the primer layer, the encapsulant layer material is dispensed to the solar cell, and with the primer layer, the encapsulant layer material is dispensed to the primer layer.  FIGS. 10E, 11E, 11F, and 11G  correspond to step S 150  of  FIG. 9 . 
     The liquid encapsulant layer material  830 ′ includes silicon and may additionally include a curing agent, a sunscreen, and an adhesive. For example, referring to  FIG. 10E , liquid silicon and a sunscreen may be dispensed from a dispenser A, and a curing agent may be dispensed from a dispenser B. In cases where the liquid encapsulant layer material  830 ′ includes an adhesive, an encapsulant layer may be bonded to the solar cell  820  even without the primer layer  880 . The liquid encapsulant layer material  830 ′ is dispensed to every exposed region of the PCB  810 . 
     Referring to  FIG. 11E , the liquid encapsulant layer material  830 ′ may be dispensed to be flat on the solar cell  820  or the primer layer  880 . When the liquid encapsulant layer material  830 ′ is dispensed to be flat, a thickness of an encapsulant layer may be formed to be even. If a thickness of the encapsulant layer is not even, the encapsulant layer may partially have low light transmittance. In order for the liquid encapsulant layer material  830 ′ to be dispensed to be flat, the liquid encapsulant layer material  830 ′ is required to have sufficiently spreading characteristics, and thus, in order for the liquid encapsulant layer material  830 ′ to have sufficiently spreading characteristics, the liquid encapsulant layer material  830 ′ may have low viscosity of 10 Pa·s or less. 
     When the liquid encapsulant layer material  830 ′ has viscosity of 10 Pa·s or less, the liquid encapsulant layer material  830 ′ may flow to an outer side of the PCB  810 . However, the dam layer  840  previously formed on the PCB  810  blocks flow of the liquid encapsulant layer material  830 ′. Thus, flowing of the liquid encapsulant layer material  830 ′ to the outside of the PCB  810  is prevented by the dam layer  840 . 
       FIGS. 11F and 11G  are modifications of  FIG. 11E . Referring to  FIG. 11F , the liquid encapsulant layer material  830 ″ may be dispensed to be thickest in a middle portion thereof and reduced in thickness toward opposing end portions thereof. Here, the middle portion corresponds to a position facing a portion between the second solar cell  822  and the third solar cell  823 , and the opposing end portions refer to a left side of the first solar cell  821  and a right side of the fourth solar cell  824 . A form in which the encapsulant layer material  830 ″ is dispensed may be varied by adjusting viscosity of the encapsulant layer material  830 ″. 
     Referring to  FIG. 11G , a unit grid of the dam layer  840  is formed at every edge of each of the solar cells  821 ,  822 ,  823 , and  824 , and a encapsulant layer material  830 ′″ may be disposed to an upper surface of each of the solar cells  821 ,  822 ,  823 , and  824 . 
     Referring back to  FIG. 9 , a liquid encapsulant layer material is thermally cured to form an encapsulant layer (S 160 ).  FIG. 10F  corresponds to step S 160 . 
     Referring to  FIG. 10F , a process of curing the liquid encapsulant layer material  830 ′ by applying heat Q is illustrated. Conditions for thermal curing the liquid encapsulant layer material  830 ′ may be varied depending on silicon included in the encapsulant layer material  830 ′. In general, when the encapsulant layer material  830 ′ is thermally treated at 130° C. to 150° C. for 30 to 150 minutes, the encapsulant layer material  830 ′ is cured to form the encapsulant layer  830  (please refer to  FIG. 10F ). When the encapsulant layer  830  is formed, a solar cell module assembly is formed. 
     Referring back to  FIG. 9 , the solar cell module assembly formed by steps S 110  to S 160  is cut to a unit size of a solar cell module (S 170 ). Since the unit grid has a size corresponding to the solar cell module  100 , when the solar cell module assembly is cut along the boundary of the unit grid, the solar cell module assembly may be cut to the unit size of the solar cell module.  FIG. 10G  illustrates a process of cutting the solar cell module assembly to a unit size of the solar cell module  800 .  FIG. 11H  illustrates the solar cell module  800  cut to the unit size. 
       FIG. 12  is a flow chart illustrating a process of manufacturing a solar cell module  500 ,  600 , or  700  (please refer to  FIGS. 5 to 7 ) of a second embodiment.  FIGS. 13A to 13E  are conceptual views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 12 .  FIGS. 14A to 14F  are cross-sectional views illustrating a process of manufacturing a solar cell module according to the method of manufacturing a solar cell module illustrated in  FIG. 12 . 
       FIGS. 13A to 13F  illustrate a process of manufacturing a plurality of solar cell modules, and  FIGS. 14A to 14F  illustrate a process of manufacturing one of a plurality of solar cell modules. 
     As described above, the solar cell modules  500 ,  600 , and  700  of the second embodiment do not include dam layers  240 ,  340 , and  440  (please refer to  FIGS. 2 to 4 ). Thus, the method for manufacturing the solar cell modules  500 ,  600 , and  700  of the second embodiment is differentiated from the method of manufacturing the solar cell modules  200 ,  300 , and  400  of the first embodiment in that it does not include steps of forming the dam layers  240 ,  340 , and  440 . Thus, the above descriptions of the method for manufacturing the solar cell modules  200 ,  300 , and  400  of the first embodiment will be used for the method for manufacturing the solar cell modules  500 ,  600 , and  700  of the second embodiment and redundant descriptions will be omitted. 
     Referring to  FIG. 12 , in order to manufacture a solar cell module, first, a PCB  910  having an electrode connection part is prepared (S 210 ).  FIGS. 13A and 14A  correspond to step S 210  of  FIG. 12 . 
     Referring to  FIG. 13A , the PCB  910  is divided into a plurality of regions, and an electrode connection part  960  is formed in each of the regions. The electrode connection part  960  may have been solder-processed. Wirings other than the electrode connection part  960  may be formed within the PCB  910 . 
     The electrode connection part  960  includes a first electrode connection part  961  to a fifth electrode connection part  965 . The first electrode connection part  961  to the fifth electrode connection part  965  are disposed to be spaced apart from each other. The number of the electrode connection parts  961 ,  962 ,  963 ,  964 , and  965  may be varied depending on a design of a solar cell module. 
     In  FIG. 13A , a first surface of the PCB  910  is illustrated, and a second surface of the PCB  910  is illustrated in  FIG. 14A . Referring to  FIG. 14A , the electrode connection part  960  is exposed to the first surface of the PCB  910 , and output terminals  951  and  952  are formed on the second surface of the PCB  910 . As illustrated in  FIG. 19A , the output terminals  951  and  952  may be formed on one side and the other side of the second surface. Alternatively, the output terminals  951  and  952  may be formed abreast on the second surface, and both the output terminals  951  and  952  may be formed on the first surface or the output terminals  951  and  952  may respectively be formed on the first surface and the second surface. 
     Referring back to  FIG. 12 , the PCB is divided into a plurality of regions having a unit size of a solar cell module, and at least one solar cell is mounted in each region (S 230 ). The solar cell is mounted on the first surface of the PCB and the number of solar cells may be varied depending on a design of a solar cell module.  FIGS. 13B and 14B  correspond to step S 230  of  FIG. 12 . 
     Referring to  FIG. 13B , four solar cells  921 ,  922 ,  923 , and  924  are respectively mounted in each region of the PCB  910 . Referring to  FIG. 14D , the solar cells  921 ,  922 ,  923 , and  924  are disposed to be spaced apart from each other and physically and electrically connected to the electrode connection parts  960  formed on a first surface of the PCB  910 . The electrode connection parts  960  are soldered, and thus, when the electrode connection parts  960  are placed on the PCB  910  and heated, the solar cell  920  may be bonded to the electrode connection part  960 . However, a method for mounting the solar cell  920  on the PCB  910  is not limited thereto and the solar cell  920  may be mounted using solder paste or soldering. 
     Referring back to  FIG. 12 , a primer layer is formed on the solar cell (S 240 ). The primer layer serves to bond an encapsulant layer to the solar cell.  FIG. 14C  corresponds to step S 240  of  FIG. 12 . 
     Referring to  FIG. 14C , a primer layer  980  is formed on the solar cell  980 . In step S 240  of forming the primer layer  980 , a primer material is disposed on the solar cell  920  and thermally cured. The thermally curing the primer material is performed such that the primer material is heat-treated for 20 to 40 minutes at temperatures 90° C. to 110° C. 
     However, in the solar cell module, the primer layer  980  is not essential, and thus, step S 240  of forming a primer layer is not essential in the method of manufacturing a solar cell module. Thus, step S 240  of forming a primer layer may be omitted and step S 250  of dispensing an encapsulant layer material may be performed immediately after step S 230  of mounting a solar cell. 
     Referring back to  FIG. 12 , a liquid encapsulant layer material is dispensed (S 250 ) after step S 230  of mounting a solar cell or after step S 240  of forming a primer layer. Without the primer layer, the encapsulant layer material is dispensed to the solar cell, and with the primer layer, the encapsulant layer material is dispensed to the primer layer.  FIGS. 13C, 14D, and 14E  correspond to step S 250  of  FIG. 12 . 
     The liquid encapsulant layer material  930 ′ includes silicon and may additionally include a curing agent, a sunscreen, and an adhesive. Referring to  FIG. 13C , 
     The liquid encapsulant layer material  930 ′ includes silicon and may further include a curing agent, a sunscreen, and an adhesive. Referring to  FIG. 13C , liquid silicon and a sunscreen may be dispensed from the dispenser A, and a curing agent may be dispensed from the dispenser B. A boundary of the encapsulant layer material  930 ′ may be formed in every boundary of each region of the PCB  910  or in each of the solar cell  921 ,  922 ,  923 , and  924 . 
     Referring to  FIG. 14D , the liquid encapsulant layer material  930 ′ preferably forms a liquid drop having a contact angle of an acute angle on the solar cell  920  or the primer layer  980 . Also, the encapsulant layer material  930 ′ is required to have sufficiently high viscosity, so that the encapsulant layer material  930 ′ is prevented from flowing out of the PCB  910  without a dam layer. To this end, the liquid encapsulant layer material  930 ′ preferably has high viscosity of 40 Pa·s or higher. 
     Since the encapsulant layer material  930 ′ has sufficiently high viscosity, step S 120  (please refer to  FIG. 9 ) of forming a dam layer in the method for manufacturing a solar cell module may be omitted. Accordingly, the number of processes may be reduced, economic efficiency of the manufacturing method may be enhanced, and efficiency of the solar cell module may also be enhanced. Enhancement of efficiency of the solar cell module has been described above. 
       FIG. 14E  is a modification of  FIG. 14D . Referring to  FIG. 14E , a liquid encapsulant layer material  930 ″ may be dispensed to be thickest in a position facing a middle portion of each of the solar cells  921 ,  922 ,  923 , and  924  and reduced in thickness toward opposing end portions of each of the solar cells  921 ,  922 ,  923 , and  924 . A form of dispensing the encapsulant layer material  930 ″ may be varied by adjusting viscosity of the encapsulant layer material  930 ″. Referring back to  FIG. 12 , the encapsulant layer material  930 ″ is thermally cured to form an encapsulant layer (S 260 ).  FIG. 13D  corresponds to step S 260  of  FIG. 12 . 
     Referring to  FIG. 13D , a process of curing the liquid encapsulant layer material  930 ′ by applying heat Q thereto is illustrated. Conditions for thermally curing the liquid encapsulant layer material  930 ′ may be varied depending on silicon included in the encapsulant layer material  930 ′. In general, when the encapsulant layer material  930 ′ is heat-treated at 130° C. to 170° C. for 30 to 150 minutes, the encapsulant layer material  930 ′ is cured to form the encapsulant layer  930  (please refer to  FIG. 13E ). When the encapsulant layer  930  is formed, a solar cell module assembly is formed. 
     Referring back to  FIG. 12 , the solar cell module assembly formed by steps S 210  to S 260  is cut to a unit size of a solar cell module (S 270 ).  FIG. 13E  illustrates a process of cutting the solar cell module assembly to a unit size of a solar cell module.  FIG. 14F  illustrates the solar cell module  900  cut to the unit size. 
     The solar cell modules  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 , and  900  described above may be used to supply electric power to an electronic device. Hereinafter, a method for manufacturing an electronic device having a solar cell module will be described. 
       FIG. 15  is a flow chart illustrating a method of manufacturing an electronic device having a solar cell module. 
     First, a solar cell module having an encapsulant layer formed of a material including silicon is manufactured (S 1100 ). The method for manufacturing a solar cell module may be referred to the above descriptions related to  FIGS. 9 to 14F , and the solar cell modules  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 , and  900  manufactured by the method for manufacturing a solar cell module may be referred to the above descriptions related to  FIGS. 1 to 8 . 
     Next, the solar cell module is mounted on a main PCB of an electronic device through a surface mount technology (SMT) of mounting a component on a main PCB of an electronic device by applying heat in a furnace (S 1200 ). A temperature of heat applied to the solar cell module through the SMT is about 200° C. to 250° C., and the SMT is performed through an automation process. 
     Automation equipment mounts the solar cell modules  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 , and  900  and various element or various circuits on the main PCB, and when heat is applied, while the solar cell modules  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 , and  900  and various element or various circuits mounted on the main PCB are passing through the furnace, the solar cell module and various element or various circuits are bonded to the main PCB. 
     The solar cell module of the present disclosure has an encapsulant layer formed of a material including silicon, and silicon has sufficient heat resistance even at a temperature of a process to which the SMT is applied. Thus, although the solar cell module is mounted on the main PCB through the high temperature SMT, the encapsulant layer is not melted or deformed. 
     Hereinafter, a sensor module will be described as an example of a solar cell module. The sensor module described hereinafter includes a solar cell and operates using electric power produced by the solar cell. 
       FIGS. 16A and 16B  are perspective views of a first embodiment of an integrated sensor module including a solar cell and a circuit component, viewed in different directions. 
       FIGS. 16A and 16B  are perspective views of a first embodiment of an integrated sensor module  1000  including a solar cell and a circuit component, viewed in different directions. 
     The sensor module  1000  includes a PCB  1010 , a solar cell  1020 , a circuit component  1300 , a sensor part  1400 , and a battery  1500 . 
     The PCB  1010  has a first surface and a second surface facing in mutually opposite directions. The first surface is illustrated in  FIG. 16A  and the second surface is illustrated in  FIG. 16B . The first surface may be termed an upper surface or a front surface, and the second surface may be termed a lower surface or a rear surface. 
     The PCB  1010  has an electrode connection part  1060  on the first surface. Electrode connection parts  1062 ,  1063 , and  1064  are disposed to be spaced apart from each other and connect the solar cells  1021 ,  1022 ,  1023 , and  1024  mounted on the first surface of the PCB  1010  in series. 
     The PCB  1010  has a circuit wiring  1011  on the second surface. The circuit wiring  1011  electrically connects electronic components mounted on the PCB  1010 , and the electronic components refer to various sensors of the sensor part  1400 , the circuit component  1300 , and the battery  1500 . 
     The electrode connection part  1060  and the circuit wiring  1011  may be electronically connected by a wiring formed within the PCB  1010 . A structure of a through hole or via hole may be formed within the PCB  1010 , and a wiring disposed in the through hole or via hole may be connected to the electrode connection part  1060  and the circuit wiring  1011 . 
     The solar cell  1020  is mounted on the first surface of the PCB  1010  and electrically connected to the electrode connection part  1060 . In  FIG. 16A , a configuration in which four solar cells  1021 ,  1022 ,  1023 , and  1024  are mounted on the first surface of the PCB  1010  is illustrated. Since the electrode connection part  1060  and the circuit wiring  1011  are electrically connected, the solar cell is electrically connected to the circuit component  1300  and the battery  1500  described hereinafter. 
     The solar cell  1020  produces electric power required for driving the circuit component  1300  and the sensor part  1400  using light. Since the sensor module  1000  is driven using electric power produced by the solar cell  1020 , the sensor module  1000  may be continuously driven even without a separate power cable. 
     Reference numeral  1030  denotes an encapsulant layer, and  1040  denotes a dam layer. The encapsulant layer and the dam layer are the same as those described above, so description thereof are omitted. 
     Referring to  FIG. 16B , the circuit component  1300  is mounted on the second surface of the PCB  1010  and electrically connected to the circuit wiring  1011 . The circuit component  1300  includes various element and various components for driving and controlling the sensor module  1000 . For example the circuit component  1300  may include a driving circuit, a charging circuit, a maximum power point tracking (MPPT) algorithm circuit, a DC-to-DC (boost or buck) converter, a communication unit implementing Internet of things of the sensor module  1000 , a power source of a sensor part, a battery charging circuit, and the like. Types of the elements and circuits may be changed according to a design of the sensor module  1000 . 
     The sensor part  1400  is an example of an electric element driven by electric power generated by the solar cell. Since the electric element has a solar cell module, the solar cell module may operate as the sensor module  1000 . In the present disclosure, types of the electric element are not limited to the sensor part  1400  and various element may be provided according to a design of the solar cell module. This is not limited to the embodiment described herein. 
     The sensor part  1400  senses a change in a measurement target. The measurement target refers to a physical amount such as a concentration of a material, light or ultrasonic wave, temperature, humidity, and the like, for example. 
     The sensor part  1400  may be mounted on the first surface and/or the second surface. A mounting position of the sensor part  1400  may be varied depending on whether the sensor part  1400  is required to be exposed to light or an external environment. The sensor module  1000  is covered by a case  2800  (please refer to  FIG. 17 ) so as to be protected, and only the first surface is exposed to light to receive light of the solar cell  1020 . Thus, the sensor required to be exposed to light or an external environment may be mounted on the first surface together with the solar cell  1020 , and any other sensor not required to be exposed may be mounted on the second surface so as to be protected. 
     For example, a temperature sensor is configured to sense a temperature through contact with air, a humidity sensor is configured to sense humidity through contact with moisture included in the air, and a gas sensor is configured to contact a gas in the air to sense the presence and absence of a gas and a concentration of the gas. Thus, the temperature sensor, the humidity sensor, and the gas sensor is not required to be exposed to light or an external environment. When a vent hole is provided in the case, air may flow through the vent hole so as to be in contact with the temperature sensor, the humidity sensor, and the gas sensor mounted on the second surface. 
       FIG. 16B  illustrates a configuration in which the sensor part  1400  is mounted on the second surface. When the sensor part  1400  includes at least one of the temperature sensor, the humidity sensor, and the gas sensor, the sensor part  1400  is preferably mounted on the second surface to protect the corresponding sensor. Also, when the sensor part  1400  is mounted on the second surface, the first surface may be entirely utilized to dispose the solar cells  1020 . 
     Since the sensor module  1000  includes the battery  1500  coupled to the second surface of the PCB  1010 , electric power produced by the solar cell  1020  may be stored in the battery  1050 . Light may not exist depending on an environment, and thus, without the battery  1500 , the sensor module  1000  may operate only when light is present. However, since the sensor module  1000  includes the battery  1500 , electric power produced by the solar cell  1020  when light is present may be stored in the battery  1500  and may be used to drive the sensor module  1000  when light is not present. 
     In the sensor module  1000  described above, the first surface of the PCB  1010  is used to mount the solar cell  1020  and the second surface is used to mount the circuit component  1300 , the sensor part  1400 , and the battery  1500 . 
     In particular, the sensor module  1000  of the present disclosure may be formed by applying an automation process employing a high temperature SMT. Here, opposing surfaces of the PCB  1010  may be utilized to mount components of the sensor module  1000 , while applying the automation process based on the high temperature SMT, because the encapsulant layer  1030  has sufficient heat resistance during the automation process using the high temperature SMT. 
     The sensor module  1000  of the present disclosure has the encapsulant layer  1030  formed of a material including silicon, and the encapsulant layer  1030  has sufficient heat resistance even in a process using the SMT having a high temperature (maximum of about 250° C. Thus, although the circuit component  1300 , the sensor part  1400 , and the like, are mounted on the second surface through the process using the high temperature SMT in a state in which the solar cell  1020  and the encapsulant layer  1030  are placed on the first surface of the PCB  1010 , the encapsulant layer  1030  is not melted or deformed. 
     Also, in the sensor module  1000  of the present disclosure, since the solar cell  1020  is mounted on the PCB  1010  and the encapsulant layer  1030  is formed without thermo-compression bonding of lamination, it is possible to first form the solar cell  1020  and the encapsulant layer  1030  on the first surface of the PCB  1010  and subsequently mount the circuit component  1300  on the second surface through the SMT. 
     That is, in the present disclosure, since the encapsulant layer  1030  is not melted or deformed and since mounting of the solar cell  1020  and forming of the encapsulant layer are conducted without thermo-compression bonding, the process of forming the solar cell  1020  and the encapsulant layer  1030  and a high temperature process of mounting the circuit component  1300 , and the like, may be freely changed. 
     In the solar cell module described above with reference to  FIGS. 1 to 7 , the output terminals are provided on the second surface of the PCB, but the sensor module  1000  described above with reference to  FIGS. 16A and 16B  do not have output terminals on the second surface of the PCB. The reason is because, the solar cell module described above has a structure formed on the assumption that the solar cell module is mounted on the main PCB, but the sensor module  1000  described herein has a structure in which the output terminals are already connected to the circuit component by the circuit wiring on the PCB.  FIGS. 16A and 16B  illustrate a structure in which the solar cell  1020  and the circuit component  1300  are formed on different surfaces of the PCB  1010 , but both the solar cell  1020  and the circuit component  1300  may be mounted together on the same surface of the PCB  1010 . 
       FIG. 17  is a cross-sectional view of a sensor module  2000  including a case  2800  and a window  2900 . The cross-sectional view of  FIG. 17  is taken along line B-B of  FIG. 16B . 
     A PCB  2010  has a multi-layer structure. For example, a plurality of insulating layers may be sequentially stacked to form the multi-layer structure of the PCB  2010 . Multilayer refers to that circuit wirings  2011  provided in the PCB  2010  form layers and connected three-dimensionally, and the number of layers may be a natural number of 2 or greater. 
     The circuit wirings  2011  include an inner layer wiring  2011   a  and an outer layer wiring  2011   b . The circuit wiring  2011  illustrated in  FIG. 16  is the outer layer wiring  2011   b  and exposed to the second surface of the PCB  2010 . The inner layer wiring  2011   a  is formed on each layer of the multilayer structure and is electrically connected to electrode connection parts  2061 ,  2062 , and  2064  through a through hole  2012  penetrating through the multilayer structure. 
     When the PCB  2010  having the multilayer structure is used in the sensor module  2000 , high density component mounting and a reduction in a wiring distance may be realized. Thus, the PCB  2010  having a multi-layer structure is appropriate for miniaturization of the sensor module  2000 . 
     A solar cell  2020  mounted on a first surface and a circuit component  2300  mounted on a second surface may be electrically connected by the outer layer wiring  2011   b , the inner layer wiring  2011   a  penetrating through the multilayer structure, and the electrode connection parts  2061 ,  2062 , and  2064 . 
     The case  2800  covers the PCB  2010  to protect the other components of the sensor module  2000 . The case  2800  is configured to protect the other part excluding the front surface of the PCB  2010 . Vent holes  2801  and  2802  described above are formed on the case  2800 . 
     Coupling parts  2810  and  2820  having a latch structure may be provided on the case  2800 . When both ends of the PCB  2010  are inserted into recesses of the coupling parts  2810  and  2820 , the PCB  2010  may be fixated to the coupling parts  2810  and  2820 . 
     The coupling parts  2810  and  2820  serves to make the PCB  2010  spaced apart and farther than electronic component such as the circuit components  2301  and  2302  from a bottom surface of the case such that the electronic component such as the circuit components  2301  and  2302  mounted on the second surface of the PCB  2010  are not in contact with the bottom surface of the case  2800 . Accordingly, when the PCB  2010  is fixated by the coupling parts  2810  and  2820 , electronic component such as the circuit components  2301  and  2302  are not in contact with the bottom surface of the case  2800 . 
     The window  2900  is disposed to face a front side of the solar cell  2020  to protect the solar cell  2020 . The window  2900  is formed of a transparent material to allow light to be supplied to the solar cell  2020 . 
     When the PCB  2010  with the solar cell  2020  and the circuit components  2301  and  2302  mounted on opposing surfaces thereof is inserted into a space formed by the case  2800  and the window  2900  is coupled to the case  2800  to protect the front side of the solar cell  2020 , the sensor module  2000  of a single product is formed. 
     In  FIG. 17 , reference numerals  2021 ,  2022 ,  2023 , and  2024  denote solar cells,  2021   a ,  2021   b ,  2022   a ,  2023   b , and  2024   a  denote electrode parts of the solar cells (reference numerals of the other electrode parts are omitted),  2030  denotes an encapsulant layer, and  2080  denotes a primer layer.  2400  denotes a sensor part, and  2500  denotes a battery. 
       FIGS. 18A and 18B  are perspective views of a second embodiment of an integrated sensor module including a solar cell and a circuit component, viewed in different directions. 
     A sensor module  3000  of the second embodiment is different from the first embodiment in that the sensor module  300  includes a sensor part  3400  mounted on a first surface. Thus, the same descriptions as those of the sensor module  2000  of the first embodiment will be omitted. 
     The sensor module  3000  includes a PCB  3010 , a solar cell  3020 , a circuit component  3300 , a sensor part  3400 , and a battery  3500 . 
     The sensor part  3400  may be mounted on a first surface and/or a second surface. A mounting position of the sensor part  3400  may be varied depending on whether it is required to be exposed to light or an external environment as mentioned above. 
     An infrared sensor is configured to sense the presence or absence of an object or measure a distance to the object using infrared ray. An ultrasonic sensor is configured to sense the presence or absence of an object or measure a distance to the object using ultrasonic waves. An illumination sensor is configured to measure brightness of light. Thus, the infrared sensor, the ultrasonic sensor, and the illumination sensor are required to be exposed to light or an external environment, and if not, the infrared sensor, the ultrasonic sensor, and the illumination sensor may lose the function thereof as sensors. 
       FIG. 18A  illustrates a configuration in which the sensor part  3400  is mounted on a first surface. In cases where the sensor part  3400  includes at least one of the infrared sensor, the ultrasonic sensor, and the illumination sensor, the sensor part  3400  is preferably mounted on the first surface to exhibit the functions of the sensors. Thus, in  FIG. 18A , the sensor part  3400  mounted on the first surface may be at least one of the infrared sensor, the ultrasonic sensor, and the illumination sensor. 
     In  FIGS. 18A and 18B , reference numeral  3011  denotes a circuit wiring,  3021 ,  3022 , and  3023  denote solar cells,  3030  denotes an encapsulant layer,  3040  denotes a dam layer, and  3060  denotes an electrode connection part. 
       FIG. 19  is a cross-sectional view of a case  4800 , a window  4900 , and a sensor module  3000  ( 4000  in  FIG. 19 ) illustrated in  FIGS. 18A and 18B . The cross-sectional view of  FIG. 19  is taken along line C-C of  FIG. 18B . 
     A PCB  4010  has a multi-layer structure. For example, a plurality of insulating layers may be sequentially stacked to form the multi-layer structure of the PCB  4010 . 
     In  FIG. 19 , a configuration in which a solar cell  4020  and a sensor part  4400  are mounted on a first surface of the PCB  4010 , and circuit components  4301  and  4302  and a battery  4500  are mounted on the second surface. 
     Vent holes  4801  and  4802  may be selectively formed on the case  4800 . For example, when the sensor part  4400  includes sensors which are required to be exposed to light or an external environment, like an infrared sensor, an ultrasonic sensor, and an illumination sensor, the vent hole  4801  and  4802  may be omitted. However, in cases where the sensor part  4400  includes sensor which are not required to be exposed to light or an external environment, like a temperature sensor, a humidity sensor, and a gas sensor, the vent holes  4801  and  4802  is required to be provided in the case  4800  for operations of the sensors. 
     A size of a recess provided at a left coupling part  4801  corresponds to the sum of thicknesses of the PCB  4010  and a dam layer  4040 , and a size of a recess formed at a right coupling part  4802  corresponds to a thickness of the PCB  4010 . This because the dam layer  4040  is not present at a right end portion of the PCB  4010 . 
     In  FIG. 19 , reference numeral  4011  denotes a circuit wiring,  4011   a  denotes an inner layer wiring,  4011   b  denotes an outer layer wiring,  4012  denotes a through hole,  4021 ,  4022 , and  4023  denote solar cells,  4021   a ,  4021   b ,  4022   a , and  4023   b  denote electrode parts of the solar cells (reference numerals of the other remaining electrode parts are omitted),  4061 ,  4062 , and  4064  denote electrode connection parts formed on the PCB (reference numerals of the other remaining electrode connection parts are omitted), and  4900  denotes a window. 
     Hereinafter, a method for manufacturing an electronic device having a solar cell module as an example of a sensor module will be described. 
       FIG. 20  is a flow chart illustrating a method for manufacturing a sensor module. 
       FIGS. 21A to 21C  are cross-sectional views illustrating a process of manufacturing a sensor module according to the method of manufacturing a sensor module illustrated in  FIG. 20 . 
     Referring to  FIG. 20 , first, a PCB having a first surface and a second surface is prepared (S 2100 ).  FIG. 21A  corresponds to step S 2100  of  FIG. 20 . 
     Referring to  FIG. 21A , a PCB  2010  has a first surface and a second surface facing in the mutually opposite directions. The PCB  2010  may have a multilayer structure. A circuit wiring  2011  of the PCB  2010  is provided in each layer of the multilayer structure, and includes an inner layer wiring  2011   a  and an outer layer wiring  2011   b . The inner layer wiring  2011   a  and the outer layer wiring  2011   b  are connected to the electrode connection parts  2061 ,  2062 , and  2064  of the first surface through the through hole  2012  of the multilayer structure. 
     Referring back to  FIG. 20 , a solar cell is mounted on the first surface of the PCB and an encapsulant layer is formed on the solar cell (S 2200 ).  FIG. 21B  corresponds to S 2200  of  FIG. 20 . 
     Referring to  FIG. 21B , the solar cell  2020  is mounted on the first surface of the PCB  2010 , and the encapsulant layer  2030  is formed on the solar cell  2020 . A method for forming the solar cell  2020  and the encapsulant layer  2030  on the first surface of the PCB  2010  is the same as that described above with reference to  FIGS. 9 to 14F . Also, a dam layer  2040  and a primer layer  2080  have also been described above. 
     Referring back to  FIG. 20 , a circuit component, or the like, is mounted on the second surface of the PCB and bonded through an automation process employing a high temperature SMT (S 2300 ).  FIG. 21C  corresponds to step S 2300  of  FIG. 20 . 
     Referring to  FIG. 21C , a configuration in which circuit components  2301  and  2302 , a sensor part  2400 , and a battery  2500  are mounted on the second surface of the PCB  2010  is illustrated. According to the SMT, a component is mounted on the PCB  2010  by applying heat in a furnace. The SMT is performed through an automation process. Since the encapsulant layer has sufficient heat resistance, it is not melted or deformed during the process employing the SMT. 
     This may be compared with a solar cell module having an outermost layer including an EVA encapsulant layer and a polymer protective layer. Thus, 1) a case in which a solar cell, an EVA encapsulant layer, and a polymer protective layer (hereinafter, referred to as a “solar cell”, etc.) are first stacked on the PCB and a circuit component is subsequently mounted, and 2) a case in which the circuit component is first mounted on the PCB and the solar cell, or the like, is sequentially mounted will be separately described. 
     In the first case, when the solar cell, or the like, is first mounted on the PCB, the EVA encapsulant layer and the polymer protective layer of the solar cell may be molted or deformed during a subsequent process of mounting a circuit component. The circuit component is mounted on the PCB through the high temperature SMT, and here, the EVA encapsulant layer and the polymer protective layer are melted or deformed at a temperature of the SMT. 
     In the second case, when the circuit component is first mounted on the PCB, it is difficult to mount a solar cell, or the like. The solar cell, the EVA encapsulant layer, and the polymer protective layer have a multilayer structure, and these form the multilayer structure through a process of lamination. Lamination refers to a process of forming a multilayer structure by compressing the structure on both sides by applying heat, and if a circuit component is mounted on the PCB, the PCB is not flat, making it impossible to perform compression 
     In  FIGS. 21A to 21C , reference numerals  2021 ,  2022 ,  2023 , and  2024  denote solar cells, and  2021   a ,  2021   b ,  2022   a ,  2023   b , and  2024   a  denote electrode parts of the solar cells (reference numerals of other remaining electrode parts are omitted). 
       FIG. 22  is a flow chart illustrating another method of manufacturing a sensor module. 
       FIGS. 23A to 23C  are cross-sectional views illustrating a process of manufacturing a sensor module according to the method of manufacturing a sensor module illustrated in  FIG. 22 . 
     The method of manufacturing a sensor module illustrated in  FIG. 22  (S 3100 , S 3200 , S 3300 ) is substantially the same as the method of manufacturing a sensor module described above with reference to  FIG. 20 , except mounting order of a circuit component and a solar cell. 
     Referring to  FIG. 23B , a sensor part  4400  is mounted on a first surface and circuit components  4301  and  4302  and a battery  4500  are mounted on a second surface by performing an automation process employing a high temperature SMT once or continuously (S 3200 ). Thereafter, referring to  FIG. 23C , a solar cell  4020  is mounted and an encapsulant layer  4030  is formed (S 3300 ). 
     Order of mounting the circuit component  4300  and the solar cell  4020  on the PCB  4010  may be interchanged, and, in the present disclosure, although the SMT is applied, the encapsulant layer  4030  is not melted or deformed. 
     In  FIGS. 23A to 23C , reference numeral  4011  denotes a circuit wiring,  4011   a  denotes an inner layer wiring,  4011   b  denotes an outer layer wiring,  4012  denotes a through hole,  4021 ,  4022 , and  4023  denote solar cells,  4021   a ,  4021   b ,  4022   a , and  4023   b  denote electrode parts of the solar cells (reference numerals of other remaining electrode parts are omitted),  4040  denotes a dam layer, and  4061 ,  4062 , and  4064  denote electrode connection parts (reference numerals of other remaining electrode connection parts are omitted). 
     According to the present disclosure having the configuration described above, since the solar cell module includes the encapsulant layer formed of a material including silicon, the solar cell module has sufficient heat resistance even during the process employing the SMT. Thus, although the solar cell module is mounted on the PCB through the process of employing the high temperature SMT together with the circuit component, the encapsulant layer is prevented from being melted or deformed. 
     Also, since the encapsulant layer has light transmittance higher than that of the multilayer structure of the polymer protective layer and the EVA encapsulant layer in every light wavelength region, an amount of light incident to the solar cell may be enhanced and efficiency of the solar cell may be improved. 
     Also, since the present disclosure provides the method of forming the encapsulant layer 1) using an encapsulant layer material having low viscosity with respect to a dam layer or 2) using an encapsulant layer material having high viscosity without a dam layer, the solar cell module applicable to the high temperature SMT may be manufactured using the method. Also, the solar cell module manufactured thusly may be mounted on a main PCB of an electronic device such as a sensor module through the SMT without a problem of melting or deformation. 
     Also, when an encapsulant layer is formed of a material including silicon, a base for utilizing both surfaces of the PCB to mount the solar cell and the circuit component, respectively, is prepared. Accordingly, the solar cell, or the like, may be mounted on the first surface of the PCB and the circuit component may be mounted on the second surface to form an integrated sensor module. 
     This effect may not be anticipated in a solar cell module having a polymer protective layer and an EVA encapsulant layer and is an advantageous effect obtained as the polymer protective layer and the EVA encapsulant layer are replaced with the silicon encapsulant layer of the present disclosure. 
       FIG. 24  is a perspective view illustrating a solar cell module  5100  of the present disclosure. 
     The solar cell module  5100  refers to a module having a solar cell  5130  to produce electric power from light. A module refers to a constituent unit of a machine or a system and represents an independent unit formed by assembling several electronic components or mechanical components to have a specific function. Thus, the solar cell module may be understood as indicating an independent unit having a solar cell and having a function of producing electric power from light. In particular, the solar cell module  5100  may be utilized for the purpose of a sensor. 
     The solar cell module  5100  includes cases  5191  and  5192 , a window  5180 , and components accommodated within the cases  5191  and  5192 . 
     The cases  5191  and  5192  are configured to accommodate the other remaining components of the solar cell module  5100  therein. The cases  5191  and  5192  are configured to protect regions other than a front side of the solar cell module  5100 . Referring to  FIG. 24 , the window  5180  is formed on a front side of the solar cell module  5100 , and the other remaining regions excluding the window  5180  are all protected by the cases  5191  and  5192 . 
     Components accommodated within the cases  5191  and  5192  include a first PCB  5110 , a solar cell  5130 , and a sensor part  5160  illustrated in  FIG. 24 , but not limited thereto. Any component required to be protected by the cases  5191  and  5192  may be accommodated within the cases  5191  and  5192 . 
     The cases  5191  and  5192  may include a first case  5191  and a second case  5192  which can be coupled to each other. 
     The first case  5191  may be configured to surround the circumference of the window  5180 . The first case  5191  may be formed of an opaque material and may be provided in a region not visually blocking the solar cell  5130 . Edges of the first case  5191  may be configured to be coupled to the second case  5192 . 
     The second case  5192  may form a side wall and a bottom of the solar cell module  5100 . The second case  5192  may be configured to accommodate the other remaining components of the solar cell module  5100 . A vent hole  5192   a  may be provided in the second case  5192 . The vent hole  5192   a  serves for sensors not required to be exposed to light or an external environment. The vent hole  5192   a  will be described later. 
     When the internal components of the solar cell module  5100  are required to be maintained and repaired, the first case  5191  and the second case  5192  may be separated from each other to expose the internal components. 
     The window  5180  is coupled to the cases  5191  and  5192  to cover the solar cell  5130  accommodated within the cases  5191  and  5192 . For example, a circumference of the window  5180  may be coupled to the first case  5191 . The window  5180  is disposed to face a front side of the solar cell  5130  to protect the solar cell  5130 . The window  5180  is formed of a transparent material to allow light to be provided to the solar cell  5130 . 
     The other remaining components of the solar cell module  5100  are accommodated within a spaced formed by the window  5180  and the cases  5191  and  5192 . In  FIG. 24 , a configuration in which the first PCB  5110 , the solar cell  5130 , and the sensor part  5160  are accommodated within the cases  5191  and  5192  is illustrated. 
     The solar cell  5130  is mounted on the first PCB  5110  and is disposed to be visually exposed through the window  5180 . The reason why the solar cell  5130  is disposed to be visually exposed through the window  5130  is to allow the solar cell  5130  to receive light. 
     The number of solar cells  5130  mounted on the first PCB  5110  may be determined according to a design of the solar cell module  5100 . In  FIG. 24 , a configuration in which two solar cells  5131  and  5132  are mounted on the first PCB  5110  is illustrated. 
     Similar to the solar cell  5130 , the sensor part  5160  may also be installed on the first PCB  5110  and disposed to be visually exposed through the window  5180 . The sensor part  5160  may be required to be exposed to light or an external environment depending on a type of a sensor provided in the sensor unit  5160 , and  FIG. 24  illustrates such a configuration. 
     For example, the infrared sensor is configured to sense the presence or absence of an object or measure a distance to the object using infrared ray. An ultrasonic sensor is configured to sense the presence or absence of an object or measure a distance to the object using ultrasonic waves. An illumination sensor is configured to measure brightness of light. Thus, the infrared sensor, the ultrasonic sensor, and the illumination sensor are required to be exposed to light or an external environment, and if not, the infrared sensor, the ultrasonic sensor, and the illumination sensor may lose the function thereof as sensors. 
     Thus, the sensor part  5160  illustrated in  FIG. 24  includes at least one of the infrared sensor, the ultrasonic sensor, and the illumination sensor. Went the sensor part  5160  includes only sensors required to be exposed to light or an external environment such as the infrared sensor, the ultrasonic sensor, and the illumination sensor, the aforementioned vent hole  5192   a  may be optional, because the vent hole  5192   a  serves for sensors not required to be exposed to light or an external environment. 
     Hereinafter, internal components of the solar cell module  5100  which is simplified and has a reduced size, compared with the related art will be described. 
       FIG. 25  is a perspective view illustrating components accommodated within the cases  5191  and  5192 . 
     The solar cell module  5100  includes the first PCB  5110 , a second PCB  5120 , the solar cell  5130 , an electric element  5140 , and the sensor part  5160 . 
     The first PCB  5110  has a first surface  5111  and a second surface  5112  facing in the mutually opposite directions. The first surface  5111  may be referred to as an upper surface or a front surface, and the second surface  5112  may be referred to as a lower surface or a rear surface. The surface exposed through the window  5180  described above with reference to  FIG. 24  is the first surface  5111 . 
     An electrode connection part  5114  is provided on the first PCB  5110 . The electrode connection part  5114  is exposed to the first surface  5111  and electrically connected to solar cell  5130  mounted on the first surface  5111 . However, some ( 5113  and  5115 ) (please refer to  FIG. 26 ) of the electrode connection parts of  FIG. 25  are covered by the solar cell  5130  mounted thereon. 
     The second PCB  5120  is disposed to be spaced apart from the first PCB  5110  and face the second surface  5112  of the first PCB  5110 . In relation to  FIG. 25 , the seconds PCB  5120  is disposed below the first PCB  5110 . Within the cases  5191  and  5192  described above with reference to  FIG. 24 , the first PCB  5110  and the second PCB  5120  are disposed at different levels to form a multi-stage structure. 
     Like the first PCB  5110 , the second PCB  5120  has a first surface  5121  and a second surface  5122  facing in mutually opposite directions. The first surface  5111  may be referred to as an upper surface or a front surface and the second surface  5112  may be referred to as a lower surface or a rear surface. 
     A circuit wiring  5123  is formed on the second PCB  5120 . The circuit wiring  5123  is electrically connected to an electric element  5140  mounted on the second PCB  5120  and electrically connects various elements and various circuits  5141  and  5142  belonging to the electric element  5140 . 
     The solar cell  5130  is mounted on the first surface  5111  of the first PCB  5110 . Since the first surface  5111  of the first PCB  5110  is disposed to face the window  5180  described above with reference to  FIG. 24 , the solar cell  5130  mounted on the first surface  5111  may be visually exposed through the window  5180 . 
     As the solar cell  5130  is visually exposed through the window  5180 , light may be incident to the solar cell  5130  through the transparent window  5180 . The solar cell  5130  is configured to produce electric power required for driving the solar cell module  5100  using the light. 
     The electric element  5140  is mounted on the first PCB or the second PCB  5120 . The electric element  5140  is driven with electric power produced by the solar cell  5130 . Since the electrode connection part  5114  and the circuit wiring  5123  are electrically connected by a connection part  5150  as described hereinafter, electric power produced by the solar cell  5130  may be used for driving the electric element  5140 . 
     The electronic element  5140  includes various elements and various circuits  5141  and  5142  for driving and controlling the solar cell module  5100 . The electric element  5140  includes various element and various components for driving and controlling the sensor module  1000 . For example the electric element  5140  may include a driving circuit, a charging circuit, a maximum power point tracking (MPPT) algorithm circuit, a DC-to-DC (boost or buck) converter, a communication unit implementing Internet of things of the solar cell module  5100 , a power source of the sensor part  5160 , a battery charging circuit, and the like. In  FIG. 24 , a configuration in which two elements  5141  and  5142  are mounted on the second PCB  5120  is illustrated, but types of the elements and circuits may be changed according to a design of the solar cell module  5100 . 
     The battery  5170  may be installed in the first PCB  5110  or the second PCB  5120 . The battery  5170  stores electric power produced by the solar cell  5130 . Electric power produced by the solar cell  5130  may be converted into electric power which can be stored in the battery  5170  by a power conversion circuit and subsequently stored in the battery  5170 . 
     Also, the electric power stored in the battery  5170  may be used for driving the solar cell module  5100 , and in particular, when light is not present, the solar cell module  5100  may be driven using electric power stored in the battery  5170 . 
     The connection part  5150  is connected to the first PCB  5110  and the second PCB  5120 . The connection part  5150  is configured to electrically connect the electrode connection part  5114  provided in the first PCB  5110  and the circuit wiring  5123  provided in the second PCB  5120 . Since the electrode connection part  5114  of the first PCB  5110  is electrically connected to the solar cell  5130  and the circuit wiring  5123  of the second PCB  5120  is electrically connected to the electric element  5140 , the solar cell  5130  and the electric element  5140  are resultantly electrically connected to each other by the connection part  5150 . 
     In  FIG. 25 , a configuration in which the connection part  5150  is formed by a flexible printed circuit (FPC) is illustrated. The FPC refers to a wiring unit forming a precise chemical fine circuit between a polyimide base having insulating properties and heat resistance and a cover lay to have flexibility and bendability. 
     In general, a PCB is formed as an insulator such as phenol or an epoxy and thus, the PCB is not flexible and bendable. In contrast, the FPC is flexible and bendable, and thus, a difference in level between the first PCB  5110  and the second PCB  5120  may be freely set. Accordingly, a structure of coupling parts  5192   b  and  5192   c  (please refer to  FIG. 26 ) described hereinafter may be freely changed. 
     Since the solar cell  5130  mounted on the first PCB  5110  and the electric element  5140  mounted on the second PCB  5120  are electrically connected by the connection part  5150 , electric power produced by the solar cell  5130  may be controlled by the electric element  5140 . Thus, the solar cell  5130  and the electric element  5140  may be mounted on different PCBs. 
     In order to produce sufficient electric power, a larger number of the solar cells  5130  may be provided, and in order to receive light, a plurality of solar cells  5130  are required to be disposed on one surface (surface on which light is directly shed) of the PCB. In addition, in order to drive the solar cell module  5100 , the electric element  5140  is required to be mounted on the PCB. In the related art, since a solar cell and an electric element are mounted on the same PCB, the single PCB should be divided into a region for mounting the solar cell and a region for mounting the electric element. In the related art structure, in order to increase the number of solar cells, an area of a solar cell module is inevitably increased. 
     In contrast, according to the structure of the present disclosure, the first surface of the first PCB may entirely be utilized for mounting the solar cell  5130 . The first surface  5111  of the first PCB  5110  may not need to be divided into a mounting region of the solar cell  5130  and a mounting region of the electric element  5140 . The sensor part  5160  may be inevitably mounted on the first surface  5111  of the first PCB  5110 , but it may also be possible for the sensor part  5160  to be mounted on the second PCB  5120  depending on a type of a sensor belonging to the sensor part  5160 . 
     Instead, the second PCB  5120  is utilized as a mounting region of the electric element  5140 . In addition, since the second PCB  5120  is disposed at a level different from that of the first PCB  5110  to overlap the first PCB  5110 , rather than being disposed to be coplanar with the first PCB  5110 , an area occupied by the solar cell module  5100  may be reduced, relative to the related art. 
     Also, since the structure of the present disclosure does not require a complicated cable connection between components, the structure of the solar cell module  5100  may be simplified. In particular, the structure in which components are connected by a cable causes a difficulty of maintenance, and thus, the structure of the present disclosure facilitates maintenance of the solar cell module  5100 . 
     Also, when the area occupied by the solar cell module  5100  is reduced, limitations in an installation place of the solar cell module  5100  may be mostly resolved. The solar cell module  5100  having the solar cell  5130  is limited in direction because it is required to be disposed to face a light incident direction to receive light and limited in size because it should be installed in a narrow space according to circumstances. However, when the area occupied by the solar cell module  5100  is reduced by the structure of the present disclosure, the limitation in size may be resolved, and thus, the limitation in an installation place may also be resolved. 
       FIG. 26  is a cross-sectional view of the solar cell module  5100 . 
     Electrode connection parts  5113 ,  5114 , and  5115  are formed on a first surface  5111  of the first PCB  5110 . The solar cells  5131  and  5132  have two electrodes  5131   a  and  5131   b  and  5132   a  and  5153   b , respectively, and the electrodes  5131   a  and  5131   b  and  5132   a  and  5132   b  are electrically connected to the electrode connection parts  5113 ,  5114 , and  5115 . Accordingly, the solar cells  5131  and  5132  are connected in series. 
     The encapsulant layer and/or the protective layer  5135  are configured to cover the solar cell. The encapsulant layer and/or the protective layer  5135  may be formed of various materials. For example, the polymer protective layer may be bonded to the solar cell by an EVA encapsulant layer or a PC (polycarbonate) encapsulant layer. Also, in this case, the polymer protective layer corresponds to an outermost layer protecting the solar cell. 
     In another example, the encapsulant layer may be formed of a material including silicon. Silicon advantageously has high heat resistance, relative to an EVA encapsulant layer. Since silicon may form an outermost layer of the solar cell module, a separate protective layer is not required. 
     A circuit wiring  5123  is formed on the second PCB  5120 , and the circuit wiring  5123  may be exposed to the first surface  5121  of the second PCB  5120 . The electric element  5140  and the battery  5170  is mounted on the first surface  5121  of the second PCB  5120  and electrically connected to the circuit wiring  5123 . 
     In  FIG. 26 , a component is not mounted on the second surface  5112  of the first PCB  5110  and the second surface  5122  of the second PCB  5120 , but, if necessary, a component may be mounted on the second surfaces  5112  and  5122 . Components mounted on the second surfaces  5112  and  5122  may be electrically connected by the connection part  5150 , and this structure will be described later. 
     Coupling parts  5192   b  and  5192   c  may be provided on the cases  5192 . Referring to  FIG. 26 , the coupling parts  5192   b  and  5192   c  protrude from a bottom of the second case  5192 . The coupling parts  5192   b  and  5192   c  are provided to fixate the first PCB  5110  and the second PCB  5120  at different levels. For example, as illustrated in  FIG. 26 , latch type recesses may be provided on the coupling parts  5192   b  and  5192   c . Two recesses forming a difference in level are formed at each of the coupling parts  5192   b  and  5192   c , and the first PCB  5110  and the second PCB  5120  are inserted into the recesses. 
     The first PCB  5110  and the second PCB  5120  may be fixated to different levels by the coupling parts  5192   b  and  5192   c  and may face each other. In the present disclosure, a structure for fixating the first PCB  5110  and the second PCB  5120  is not limited and any structure may be used as long as it can fixate the first PCB  5110  and the second PCB  5120  are fixated at different levels. 
     In  FIG. 26 , reference numeral  5180  denotes a window, and the window  5180  is the same as that described above. 
       FIGS. 27A to 27C  are conceptual views illustrating an example of a method for manufacturing a solar cell module. 
     First, referring to  FIG. 27A , the electrode connection parts  5113 ,  5114 , and  5115  are formed on the first PCB  5110 , and the solar cell  5130  is mounted on the first PCB  5110  and electrically connected to the electrode connection parts  5113 ,  5114 , and  5115 . The solar cell  5130  may be mounted in various manners. For example, the solar cell  5130  may be bonded to the electrode connection parts  5113 ,  5114 , and  5115  using solder. 
     Next, referring to  FIG. 27B , a liquid encapsulant layer material  5135 ′ is dispensed to the solar cell  5130  and heat is applied thereto to form an encapsulant layer  5135 . The encapsulant layer  5135  may be an outermost layer covering the solar cell  5130  as necessary. For example, in cases where the encapsulant layer  5135  is formed of a material including silicon, the encapsulant layer  5135  may not require a separate protective layer. 
     The silicon encapsulant layer is formed by dispensing a liquid encapsulant layer material  5135 ′ to the solar cell and applying heat Q to thermally cure the liquid encapsulant layer material  5135 ′. If the liquid encapsulant layer material  5135 ′ does not include an adhesive, a primer layer providing adhesive strength may be formed between the solar cell  5130  and the encapsulant layer  5135 . 
     At least some of electric elements, in addition to the solar cell  5130 , may be mounted on the first PCB  5110 , and types and number of electric elements may be varied depending on a design. An electric element mounted on the first PCB  5110  may be mounted on the first surface  5111  or the second surface  5112  of the first PCB  5110 . A configuration in which an electric element is mounted on the first PCB  5110  is illustrated in  FIGS. 29 and 30 . 
     In particular, since the silicon encapsulant layer  5135  has high heat resistance as mentioned above, in cases where an electric element is intended to be mounted on the first PCB  5135 , an automation process employing a high temperature SMT may be used. The automation process employing the high temperature SMT refers to a process of bonding a PCB and an electric element by applying heat in a furnace. Forming the silicon encapsulant layer  5135  on the first PCB  5110  and mounting an electric element may be interchanged in order. 
     Thereafter, as illustrated in  FIG. 27C , a circuit wiring  5123  is formed on the second PCB  5120 , and an electric element  5140  is mounted on the second PCB  5120  and electrically connected to the circuit wiring  5123 . Finally, when the first PCB  5110  and the second PCB  5120  are connected by the connection part  5150 , the solar cell  5130 , or the like, mounted on the first PCB  5110  and the electric element  5140 , or the like, mounted on the second PCB are electrically connected. In  FIG. 27C , reference numeral  5170  is a battery. 
       FIGS. 28A to 28E  are conceptual views illustrating another example of a method for manufacturing a solar cell module. 
     First, referring to  FIG. 28A , the electrode connection parts  5113 ,  5114 , and  5115  are formed on the first PCB  5110 , and the solar cell  5130  is mounted on the first PCB  5110  and electrically connected to the electrode connection parts  5113 ,  5114 , and  5115 . 
     Next, referring to  FIG. 28B , the encapsulant layer  5135  is stacked on the solar cell  5130 . Also, referring to  FIG. 28C , a protective layer  5136  is stacked on the encapsulant layer  5135 . Thereafter, referring to  FIG. 28D , the first PCB  5110 , the solar cell  5130 , the encapsulant layer  5135 , and the protective layer  5135  are compressed (P) from both side, while applying heat Q thereto, during a lamination process, to bond the protective layer  5136  to the solar cell  5130 . 
     The encapsulant layer  5135  may be formed of EVA or PC as described above, and the protective layer  5136  may be formed of a polymer. During the lamination process, as the encapsulant layer  5135  are melted and thermally cured, the protective layer  5136  is bonded to the solar cell  5130 . 
     As described above, at least some of electric elements, in addition to the solar cell  5130 , may be mounted on the first PCB  5110 , and types and number of the electric elements mounted on the first PCB  5110  may be varied depending on a design. An electric element mounted on the first PCB  5110  may be mounted on the first surface  5111  of the second surface  5112  of the first PCB  5110 . A configuration in which an electric element is mounted on the first PCB  5110  is illustrated in  FIGS. 29 and 30 . 
     Next, referring to  FIG. 28E , a circuit wiring  5123  is formed on the second PCB  5120 , and the electric element  5140  is mounted on the second PCB  5120  and electrically connected to the circuit wiring  5123 . Finally, when the first PCB  5110  and the second PCB  5120  are connected by the connection part  5150 , the solar cell  5130 , or the like, mounted on the first PCB  5110  and the electric element  5140 , or the like, mounted on the second PCB  5120  are electrically connected to each other. 
     Hereinafter, other embodiments of the solar cell module will be described and a redundant description will be omitted. 
       FIG. 29  is a perspective view illustrating another embodiment of a solar cell module  5200 . 
     In  FIG. 29 , a second surface  5212  of a first PCB  5210  and a first surface  5221  of a second PCB  5220  are illustrated. A solar cell is mounted on the first surface  5211  of the first PCB  5210 . 
     A circuit wiring  5216  is formed on the second surface  5212  of the first PCB  5210 , and an electric element  5240  and a battery  5270  are mounted on the second surface  5212  and electrically connected to the circuit wiring  5216 . The electric element  5240  has a concept of including various elements and various circuits  5241  and  5242 , and thus, at least one of the electric elements  5240  mounted on the second surface  5212  may be a power conversion circuit. Electric power produced by the solar cell is converted to be appropriately stored in a battery  5270  by the power conversion circuit and subsequently stored in the battery  5270 . 
     A sensor part  5260  is mounted on the first surface  5221  or the second surface  5222  of the second PCB  5220 . A mounting position of the sensor part  5260  may be varied depending on whether the sensor part  5260  is required to be exposed to light or an external environment as described above. 
     A temperature sensor is configured to sense a temperature through contact with air, a humidity sensor is configured to sense humidity through contact with moisture included in the air, and a gas sensor is configured to contact a gas in the air to sense the presence and absence of a gas and a concentration of the gas. Thus, the temperature sensor, the humidity sensor, and the gas sensor is not required to be exposed to light or an external environment. When the vent hole  5192   a  (please refer to  FIG. 24 ) is provided in the case  5191  or  5192  (please refer to  FIG. 24 ), air may flow through the vent hole  5192   a  so as to be in contact with the temperature sensor, the humidity sensor, and the gas sensor mounted on the second PCB  5220 . 
     When the sensor part  5260  includes at least one of the temperature sensor, the humidity sensor, and the gas sensor, the sensor part  5260  is preferably mounted on the second PCB  5220  to protect the corresponding sensor. Also, when the sensor part  5260  is mounted on the second PCB  5220 , the first surface  5221  of the first PCB  5210  may be entirely utilized to dispose the solar cells. 
     A communication unit realizing Internet of things may be mounted on the first PCB or the second PCB. If a multi-stage structure of the solar cell module interferes with signal transmission and reception of the communication unit, the communication unit is preferably mounted on the first PCB. The reason is because, when the communication unit is mounted on the first PCB, a factor interfering with signal transmission and reception may be eliminated. 
     In  FIG. 29 , reference numeral  223  denotes a circuit wiring,  5240 ′ denotes an electric element mounted on the second PCB  5220 ,  5243  and  5244  denote various elements and various circuits, and  5250  denotes a connection part. 
       FIG. 30  is a perspective view illustrating another embodiment of a solar cell module  5300 . 
     In  FIG. 30 , a second surface  5312  of a first PCB  5310  and a second surface  5322  of a second PCB  5320  are illustrated. A solar cell is mounted on the first surface  5311  of the first PCB  5310 . An electric element  5345  is mounted on the second surface  5312  of the second PCB  5320 . 
     The connection part  5350  may be formed by connectors  5351 ,  5352 , and  5353 , and the first PCB  5310  and the second PCB  5320  are electrically connected by the connectors  5351 ,  5352 , and  5353 . An element such as a socket, or the like, capable of connecting the connectors  5351 ,  5352 , and  5353  to the first PCB  5310  and the second PCB  5320  is provided, and when both ends of the connectors  5351 ,  5352 , and  5353  are connected to the element, the first PCB  5310  and the second PCB  5320  may be electrically connected. 
     The connectors  5351 ,  5352 , and  5353  may be provided in plurality. In  FIG. 30 , three connectors  5351 ,  5352 , and  5353  are connected to the first PCB  5310  and the second PCB  5320 . The number and positions of the connectors  5351 ,  5352 , and  5353  may be varied according to a design of the solar cell module  5300 . 
     The connectors  5351 ,  5352 , and  5353  may be configured to support the second surface  5312  of the first PCB  5310 . As illustrated in  FIG. 30 , when the connectors  5351 ,  5352 , and  5353  are disposed between the first PCB  5310  and the second PCB  5320 , the second surface  5312  of the first PCB  5310  may be supported. 
     A battery  5370  may be mounted on the second surface  5312  of the first PCB  5310 , and thus, both surfaces  5311  and  5312  of the first PCB  5310  may be utilized for mounting a component, and similarly, both surfaces  5321  and  5322  of the second PCB  5320  may also be utilized for mounting a component. In  FIG. 30 , a configuration in which an electric element  5345  is mounted on the second surface  5322  of the second PCB  5320  is illustrated. 
     The second PCB  5320  may be fixated to the cases  5191  and  5192  (please refer to  FIG. 24 ) through screw fastening. A hole  5324  is formed on the second PCB  5320 , and a screw fastening member corresponding to the hole may be formed in the cases  5191  and  5192 . In a state in which the second surface  5322  of the second PCB  5320  is disposed to face an inner bottom surface of the cases  5191  and  5192 , when a screw is fastened to the screw fastening member through the hole  5324 , the second PCB  5230  is fixated. The number and positions of the hole  5324  and the screw fastening member may be varied according to a design. 
     In a state in which the second PCB  5320  is fixated to the cases  5191  and  5192 , when the connectors  5351 ,  5352 , and  5353  are connected to the second PCB  5320  and the first PCB  5310  is installed on the connectors  5351 ,  5352 , and  5353 , component mounting of the solar cell module  5300  within the cases  5191  and  5192  is completed. 
     In this manner, when the both surfaces  5311  and  5312  of the first PCB  5310  and both surfaces  5321  and  5322  of the second PCB  5320  are utilized for mounting components of the solar cell module  5300 , a size of the solar cell module  5300  may be further reduced. 
     According to the present disclosure having the configuration as described above, since the first PCB is utilized for stacking the solar cells and the second PCB is utilized for mounting the other remaining circuit components, a larger light receiving area may be secured, compared with a configuration in which the solar cells and circuit components are all mounted on a single PCB. 
     Also, in the present disclosure, since the first PCB and the second PCB are disposed at different levels to face each other, an area occupied by the solar cell module may be reduced, relative to the related art. 
     Also, in the present disclosure, since the size of the solar cell module is reduced, a limitation in an installation place of the solar cell module may be resolved. 
     The solar cell module, the electronic device having the same, and the method for manufacturing the solar cell module and the electronic device described above are not limited to the configurations and methods of the embodiments of the present disclosure described above and the entirety or a portion of the embodiments may be selectively combined to form various modifications. 
     The foregoing embodiments and advantages are merely by example and are not to be considered as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the example embodiments described herein may be combined in various ways to obtain additional and/or alternative example embodiments. 
     As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be considered broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.