Patent Publication Number: US-2019189822-A1

Title: Method for preparing insulating layer of flexible photovoltaic module and flexible photovoltaic module

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims priority to Chinese Patent Application No. 201711353184.X, filed on Dec. 15, 2017, the entire contents thereof are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to the technical field of solar cell, in particular to a method for preparing an insulating layer of a flexible photovoltaic module and a flexible photovoltaic module. 
     BACKGROUND 
     With the scarcity of natural resources such as petroleum and coal on the earth, the development of new natural energy has become a top priority. Among them, solar energy has become a major focus of development. At present, the conversion of solar energy into electrical energy that can be used normally uses photovoltaic modules. 
     SUMMARY 
     The present disclosure provides a method for preparing an insulating layer of a flexible photovoltaic module, comprising: 
     step S 1 : placing the flexible photovoltaic module on a spraying device, and using a shielding component to shield both side surfaces of the flexible photovoltaic module; in particular, placing the flexible photovoltaic module on a spraying device, and using a shielding component to shield the edges of the two side surfaces abutting the sidewall to be insulated of the flexible photovoltaic module; 
     step S 2 : performing a first spraying on the sidewall to be insulated of the flexible photovoltaic module to form an insulating bottom layer; 
     step S 3 : performing a second spraying on the insulating bottom layer to form an insulating top layer such that the insulating bottom layer and the insulating top layer constitute an insulating layer; and 
     step S 4 : drying the insulating layer. 
     The method for preparing an insulating layer of a flexible photovoltaic module as described above, for example, further comprises step S 10  prior to step S 1 : cleaning the flexible photovoltaic module. 
     In the method for preparing an insulating layer of a flexible photovoltaic module as described above, for example, step S 10  comprises: 
     step S 11 : using a dust-free cloth impregnated with isopropyl alcohol to remove oil and grease from the flexible photovoltaic module; and 
     step S 12 : dedusting the flexible photovoltaic module by static electricity. 
     In the method for preparing an insulating layer of a flexible photovoltaic module as described above, for example, step S 2  specifically comprises: performing the spraying by using a spray gun and setting the atomizing pressure of the spray gun in a range of about 0.3 MPa to 0.5 MPa; keeping the distance between the spray gun and the sidewall to be insulated within a range of about 10 cm to 15 cm during the spraying; forming an insulating bottom layer with a thickness of about 30 μm to 40 μm. 
     In the method for preparing an insulating layer of a flexible photovoltaic module as described above, for example, step S 3  specifically comprises: performing the spraying by using a spray gun and setting the atomizing pressure of the spray gun in a range of about 0.3 MPa to 0.5 MPa; keeping the distance between the spray gun and the sidewall to be insulated within a range of about 10 cm to 15 cm during the spraying; forming an insulating bottom layer; constituting an insulating layer with a total thickness of about 60 μm to 100 μm by the insulating bottom layer and the insulating top layer. 
     In the method for preparing an insulating layer of a flexible photovoltaic module as described above, for example, step S 4  specifically comprises: placing the flexible photovoltaic module in an infrared light box for about 5 minutes to dry the surface of the insulating layer; placing the flexible photovoltaic module dried by the infrared light box in a dust-free workshop for about 24 hours to naturally dry and solidify the insulating layer. 
     The method for preparing an insulating layer of a flexible photovoltaic module as described above, for example, further comprises, following step S 4 , step S 5 : performing an adhesion test on the formed insulation layer; and/or 
     step S 6 : performing an insulation performance test on the formed insulation layer. 
     The present disclosure also provides a flexible photovoltaic module, wherein an insulating layer is provided on a sidewall of the flexible photovoltaic module. 
     In the flexible photovoltaic module as described above, for example, the material of the insulating layer is fluoroethylene propylene or methyl vinyl silicon. 
     In the flexible photovoltaic module as described above, for example, the flexible photovoltaic module comprises, in an order from top to bottom: a PET front plate, a first adhesive film, a battery chip, a second adhesive film and an integrated back plate; and the insulating layer extends from a side of the PET front plate away from the first adhesive film to a side of the integrated back plate away from the second adhesive film. 
     The present disclosure provides a method for preparing an insulating layer of a flexible photovoltaic module comprising step S 1 : placing the flexible photovoltaic module on a spraying device, and using a shielding component to shield both side surfaces of the flexible photovoltaic module; step S 2 : performing a first spraying on the sidewall to be insulated of the flexible photovoltaic module to form an insulating bottom layer; step S 3 : performing a second spraying on the insulating bottom layer to form an insulating top layer on the insulating bottom layer such that the insulating bottom layer and the insulating top layer constitute an insulating layer; step S 4 : drying the insulating layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic structural view of a flexible photovoltaic module in the related art; 
         FIG. 2  is a flow chart of a method for preparing an insulating layer of a flexible photovoltaic module according to an embodiment of the present disclosure; 
         FIG. 3  is a schematic view of a use state of a shielding component used in a method for preparing an insulating layer of a flexible photovoltaic module according to an embodiment of the present disclosure, showing the two sideways  101  of four sideways the flexible photovoltaic module; 
         FIG. 4  is a schematic structural view of a flexible photovoltaic module according to an embodiment of the present disclosure, showing the two side surfaces  102  of the flexible photovoltaic module; 
         FIG. 5  is a schematic structural view of performing an insulation test on a flexible photovoltaic module according to an embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF THE REFERENCE NUMERALS 
     Related Art 
       1 —flexible photovoltaic module,  2 —PET front plate,  3 —first adhesive film,  4 —battery chip,  5 —second adhesive film,  6 —integrated back plate,  61 —first PET,  62 —aluminum foil,  63 —second PET 
     The Present Disclosure 
     
         
           10 —flexible photovoltaic module,  11 —insulating layer,  12 —PET front plate,  13 —first adhesive film,  14 —battery chip,  15 —second adhesive film,  16 —integrated back plate,  161 —first PET layer,  162 —aluminum foil,  163 —second PET layer,  20 —shielding component,  30 —water tank,  40 —power source,  101 —sidewall,  102 —side surface 
       
    
     DETAILED DESCRIPTION 
     The upper surface and the lower surface of the existing photovoltaic module are respectively adhered with a layer of glass, and the sideway of the glass is embodied with an aluminum frame that is grounded to prevent the photovoltaic module from being shocked. However, due to the large self-weight and rigidity of the glass, it has great limitations in practical application. In order to reduce the weight of the photovoltaic module and expand the application range of the photovoltaic module, a flexible photovoltaic module is developed. 
     Generally, a flexible photovoltaic module includes, in an order from top to bottom, a PET front plate, a first adhesive film, a battery chip, a second adhesive film, and a PET back plate. In a flexible photovoltaic module, PET (polyethylene terephthalate) is used instead of glass to encapsulate the flexible photovoltaic module. Since the water resistance of PET is insufficient, as shown in  FIG. 1 , it is necessary to add a layer of aluminum foil with a thickness of about 10 μm to 50 μm to improve the water resistance performance of the flexible photovoltaic module. In actual production, PET, which is used as back plate, and aluminum foil are often integrated into a composite material layer. The improved flexible photovoltaic module  1  includes, in an order from top to bottom, a PET front plate  2 , a first adhesive film  3 , a battery chip  4 , a second adhesive film  5 , and an integrated back plate  6 . The integrated back plate  6  includes a first PET  61 , an aluminum foil  62 , and a second PET  63  in an order from top to bottom. 
     Due to the limitations of equipment, processes, and costs for producing integrated backplate, at present, aluminum foil edges are generally designed to be flush with PET edges. Therefore, the edges of the aluminum foil are exposed to the air. If the battery chip pierces the integrated backplate, there is a risk of electric leakage. Due to the limitations of flexible photovoltaic modules, such as thin thickness and soft and flexible texture, it is difficult to achieve the grounding of the rigid aluminum frame on the periphery of the flexible photovoltaic module, and it limits the flexibility and bendability of the flexible photovoltaic module to some extent. Therefore, how to solve the problem of electric leakage of the above-mentioned improved flexible photovoltaic module without affecting the flexibility and bendability of the flexible photovoltaic module becomes a matter of urgency. 
     The present disclosure provides a method for preparing an insulating layer of a flexible photovoltaic module and a flexible photovoltaic module. In the present disclosure, an insulating layer is prepared on the sideway of the flexible photovoltaic module for insulation, thereby solving the problem of electric leakage of the flexible photovoltaic module. 
     Using the preparation method of the flexible photovoltaic module insulating layer provided by the disclosure, an insulating layer is prepared on the sidewall of the flexible photovoltaic module, thereby insulating the aluminum foil in the flexible photovoltaic module, avoiding the problem of electric leakage caused by puncturing the aluminum foil by the battery chip, without affecting the flexibility and bendability of the flexible photovoltaic module. 
     The embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary, are used to explain the present disclosure only, and not intended to limit the present disclosure. 
     As shown in  FIG. 2 , the present disclosure will be described with reference to the structural view of the flexible photovoltaic module  10  in  FIG. 4 , and a method for preparing an insulating layer of a flexible photovoltaic module according to an embodiment of the present disclosure comprises: 
     Step S 1 : placing the flexible photovoltaic module  10  on a spraying device, and using a shielding component  20  to shield both side surfaces of the flexible photovoltaic module  10 . In particular, placing the flexible photovoltaic module  10  on a spraying device, and using a shielding component  20  to shield the edges of the two side surfaces abutting the sidewall to be insulated of the flexible photovoltaic module  10 . The shielding component  20  includes two shielding plates. Specifically, after the flexible photovoltaic module  10  is placed on the spraying device, the two shielding plates are respectively attached to the two side surfaces of the flexible photovoltaic module  10 , and the edges of the two shielding plates are all flush with the sidewall to be insulated of the flexible photovoltaic module  10 . Referring to  FIG. 3 , it can be seen that after shielded by the shielding component  20 , the flexible photovoltaic module  10  only exposes the sidewall to be insulated, and the peripheral positions are shielded, so as to avoid sputtering the insulating material onto the surface of the flexible photovoltaic module  10  to block the light receiving area and affect the final conversion efficiency when the insulating layer  11  is prepared by spraying. Obviously, the way of shielding the two side surfaces is not limited to this, and thus, any way of avoid sputtering the insulating material onto the surface of the flexible photovoltaic module  1  can be adopted. 
     Step S 2 : performing a first spraying on the sidewall to be insulated of the flexible photovoltaic module  10  to form an insulating bottom layer. When spraying, a spray gun is used as the spray tool. The specific method for the first spraying comprises turning on a spray gun and adjusting the atomizing pressure of the spray gun in a range of about 0.3 MPa to 0.5 MPa; keeping the distance between the spray gun and the sidewall to be insulated within a range of about 10 cm to 15 cm; subsequently performing a first spraying on the sidewall to be insulated of the flexible photovoltaic module  10  to form an insulating bottom layer with a thickness of about 30 μm to 40 μm; and turning off the spraying gun. 
     Step S 3 : performing a second spraying on the insulating bottom layer to form an insulating top layer so that the insulating bottom layer and the insulating top layer constitute an insulating layer  11 . A spray gun is used as the spray tool when spraying. The specific method for the second spraying comprises turning on a spray gun and adjusting the atomizing pressure of the spray gun in a range of about 0.3 MPa to 0.5 MPa; keeping the distance between the spray gun and the sidewall to be insulated within a range of about 10 cm to 15 cm; subsequently performing a second spraying on the insulating bottom layer to form an insulating top layer such that the insulating layer  11  that is constituted by the insulating bottom layer and the insulating top layer has a total thickness of about 60 μm to 100 μm. The second spraying is performed on the basis of the first spraying to continue spraying. The thickness of the insulating top layer of the second spraying is about 30 μm to 60 μm. The thickness of the two sprayings is totally about 60 μm to 100 μm. The second spraying makes the insulation layer denser, making up for the holes caused by the uneven first spraying. After the first spraying, the insulating bottom layer is completed, and the second spraying can be performed directly without time interval. 
     Step S 4 : drying the insulating layer  11 . For example, infrared lamps may be used for drying. Specifically, the flexible photovoltaic module  10  is placed in an infrared light box for about 5 minutes to dry the surface of the insulating layer  11 . After being dried, the insulating layer  11  is reliably attached to the flexible photovoltaic module  10  and detachment phenomenon does not occur, such that a good insulation effect can be achieved and the electric leakage phenomenon can be avoided. Certainly, drying is not limited to the above method, and other methods may also be used. 
     After infrared drying, it is also necessary to place the flexible photovoltaic module  10  in a dust-free workshop for about 24 hours to naturally dry and solidify the insulating layer  11 . Drying naturally in the dust-free workshop can further increase the adhesion reliability of the insulating layer  11 , and no impurities are mixed in the insulating layer  11 , thereby enhancing the insulation effect and increasing the safety factor. 
     For example, the flexible photovoltaic module  10  can be cleaned prior to placing the flexible photovoltaic module  10  on the spraying device. The cleaning of the flexible photovoltaic module  10  includes the removal of oil, grease, and deposited dust. Specifically, oil and grease on the flexible photovoltaic module  10  can be removed using a dust-free cloth impregnated with isopropyl alcohol; and the flexible photovoltaic module  10  is dedusted by an electrostatic dust removal gun. When cleaning, it is focused on cleaning the sidewall to be insulated of the flexible photovoltaic module  10 , so as to prevent the oil, grease and dust from affecting the uniformity of the insulating layer  11 , thereby improving the insulation effect and aesthetics. Certainly, the cleansing liquid which impregnates the dust-free cloths is not limited to isopropyl alcohol. 
     By using the preparation method of the flexible photovoltaic module insulating layer provided by the disclosure, an insulating layer  11  is prepared on the sidewall of the flexible photovoltaic module  10 , thereby insulating the aluminum foil  162  in the flexible photovoltaic module  10 , avoiding the problem of electric leakage caused by puncturing the aluminum foil  162  by the battery chip, without affecting the flexibility and bendability of the flexible photovoltaic module  10 . 
     In order to increase the life and flexibility of the insulating layer  11 , as well as the degree of bendability, the insulating layer  11  is made of polymer nano-composites with high-insulation, high-heat-resistant, and strong-adhesion, such as fluoroethylene propylene, methyl-vinyl-silicon materials or polyurethane compounds with high-adhesion as raw materials. 
     Those skilled in the art can understand that, the flexible photovoltaic module  10  is generally rectangular with a small thickness. Therefore, it has four sidewalls  101  and two side surfaces  102 , wherein all the side walls need to be insulated. After the insulating layer  11  has been prepared for one of the sidewalls, the above steps may be repeated to form the insulating layer  11  for the remaining sidewalls. 
     After the insulation layer  11  has been formed, its adhesion needs to be tested. Specifically, when the adhesion is tested, the dried flexible photovoltaic module  10  is placed in a test box, in which the humidity is set to about 85%, and the temperature is controlled to increase from about 25° C. to 80° C. with an increase rate of about 2° C./min. After about 30 min at about 80° C., the temperature is constantly decreased to about −40° C. with a cooling rate of about 2° C./min, and maintained at about −40° C. for about 30 min. The cycle is repeated about 200 times, after which the insulation layer  11  on the flexible photovoltaic module  10  is checked to see if there are detachment and delamination. If so, the processing technology needs to be adjusted. If not, it is proved that the processing technology is qualified. 
     Further, it is also necessary to test the insulation performance of the insulating layer  11 . The specific test method is as follows. As shown in  FIG. 5 , two independent water tanks  30  are prepared, and the conductivity of the water tanks  30  needs to be greater than about 0.286 ms/cm 2 . The two sidewalls of the flexible photovoltaic module  10 , which are prepared with the insulating layer  11 , are respectively placed in two water tanks  30 , and then the two water tanks  30  are respectively connected to the positive and negative electrodes of the power source  40 , then the leakage current is detected. It is determined whether the leakage current is less than 10 μA, if yes, then it is qualified, otherwise, it is unqualified. 
     As shown in  FIG. 4 , the present disclosure further provides a flexible photovoltaic module  10 , the sidewall of which is provided with an insulating layer  11 . For example, the material of the insulating layer  11  is fluoroethylene propylene or methyl vinyl silicon, and it has a thickness of about 60 μm to 100 μm. Certainly, the specific material of the insulating layer is not limited to the listed ones. 
     The flexible photovoltaic module  10  includes, in an order from top to bottom, a PET front plate  12 , a first adhesive film  13 , a battery chip  14 , a second adhesive film  15  and an integrated back plate  16 . The insulating layer  11  extends from a side of the PET front plate  12  away from the first adhesive film  13  to a side of the integrated back plate  16  away from the second adhesive film  15 . For example, the integrated back plate  16  includes, in an order from top to bottom, a first PET layer  161 , an aluminum foil layer  162 , and a second PET layer  163 . 
     The structures, features, and effects of the present disclosure are described in detail based on the embodiments shown in the drawings. The above description only relates to the preferred embodiments of the present disclosure, but the present disclosure does not limit the scope of implementation as shown in the drawings. Any changes made according to the concept of the present disclosure, or equivalent embodiments that are modified to equivalent changes, should still fall within the protection scope of the present disclosure if they do not go beyond the scope covered by the description and the drawings.