Abstract:
A concentration photovoltaic module includes a substrate, a first electrode, a second electrode, a solar cell, at least one electrical connecting element and a frame. The first electrode and the second electrode are disposed in different predetermined positions of the substrate to form a first electrode and a second electrode, respectively. The solar cell is disposed on the first electrode. The electrical connecting element electrically interconnects the second electrode and the solar cell. The frame straddles on the substrate, wherein the solar cell is located in the frame.

Description:
[0001]    This application claims priority of No. 96119497 filed in Taiwan, R.O.C. on May 31, 2007 under 35 USC 119, the entire content of which are hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a concentration photovoltaic module, and more particularly to a solar cell module with a frame filled with a medium to prevent the outside environment from damaging the solar cell therein. 
         [0004]    2. Description of the Related Art 
         [0005]    In recent years, demand for energy has increased rapidly as industry and commerce developed continuously, and, however, the world population has been increasing also. Much attention for petrochemical energy resources has been drawn to decreasing the usage of petrochemical energy resources and environmental pollution. Thus, alternative energy resources continue to be developed in efforts to solve the above-mentioned problems. The development of solar energy, such as solar cells, is targeted to replace fossil fuels. Solar energy, which helps ease the consumption of fossil fuels, is not only available but also friendly to environment. However, in the light to electricity transformation process for presently developed solar cells, the solar cell is unable to efficiently absorb the incidental light spectrum and transform light into electricity. Specifically, about half of the photon energy has no contribution to the solar cell output due to its spectrum smaller than minimal conversion spectrum of semiconductor band gap. Meanwhile, of the absorbed other half of the photon energy, half is provided to electron-hole pairs, and the other half is released as heat. Currently, the best absorption efficiency of a single crystal silicon is about twenty percent, and the efficiency of a III-V semiconductor is about forty percent. However, it is necessary for solar cells to be placed in an outdoor environment to absorb sufficient light to generate electricity. Thus, undesirable or constantly change of outside environment may reduce lifespan and efficiency of the solar cell. Package design and materials selected are also the keys to the lifespan and reliability of solar cells. 
         [0006]      FIG. 1  shows a sectional view of a conventional concentration photovoltaic module  1 . In conventional technology, a solar cell  12  disposed on a substrate  11  is packaged via insulating materials (e.g. polymer  13 ) to avoid atmospheric dirt contact, which would decrease efficiency of the solar cell. By the conventional package method, the incidental light spectrum and reflection of solar light is affected by the package surface profile of the polymer  13 . Thus, a bad package directly decreases the energy absorption efficiency of the solar cell  12 . When the polymer  13  contacts air for a long time, moisture absorption may occur and effect of isolation and protection is seriously reduced. Therefore, a bad package can affect the lifespan and efficiency of solar cells. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    An object of the present invention is to provide a concentration photovoltaic module including a solar cell module. A frame is located in the solar cell module. An optical element is disposed on the frame. The frame has a cavity to install a solar cell. The cavity is filled with a transparent adhesive or a polymer material having better transmittance and insulating effect to prevent the solar cell from contacting the outside environment and raise the efficiency of the solar cell. 
         [0008]    Another object of the present invention is to raise the efficiency of the solar cell by controlling a height of the frame to adjust a distance and a parallelism parameter between the optical element disposed on the frame and the solar cell installed in the cavity of the frame. 
         [0009]    The present invention provides a concentration photovoltaic module including a substrate, a plurality of electrodes, a solar cell, at least one electrical connecting element, a frame and an optical element. The electrodes include a first electrode and a second electrode disposed in different predetermined positions on the substrate, respectively. The solar cell includes a first electrode electrically connected to the first electrode, and a second electrode electrically connected to the second electrode. The frame is made of a ceramic material, straddles on the substrate and includes a cavity, wherein the solar cell is installed in the cavity. The optical element is installed in an annular groove of the upper frame. The cavity, assembled by the optical element and the frame, is filled with a medium or without any material. 
         [0010]    The first electrode and one electrode of the solar cell are of the same polarity, and the second electrode and the other electrode of the solar cell are of the same polarity, and the first electrode and the second electrode are opposite in polarity. The optical element is a transparent protect cover, a polymer, a lens or an optical element having high transmittance. The medium is a transparent adhesive or a polymer material having high transmittance and insulating effect. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a sectional view of a conventional concentration photovoltaic module. 
           [0013]      FIG. 2  is an exploded view of a concentration photovoltaic module of a first embodiment of the invention. 
           [0014]      FIG. 3  is an assembling stereogram of a concentration photovoltaic module of a first embodiment of the invention. 
           [0015]      FIG. 4  is a plan view of a concentration photovoltaic module of a first embodiment of the invention. 
           [0016]      FIG. 5  is a sectional view of a concentration photovoltaic module of a first embodiment of the invention. 
           [0017]      FIG. 6  is a sectional view of a concentration photovoltaic module of a second embodiment of the invention. 
           [0018]      FIG. 7  is a sectional view of a concentration photovoltaic module of a third embodiment of the invention. 
           [0019]      FIG. 8  is a sectional view of a concentration photovoltaic module of a fourth embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]      FIGS. 2-5  show a concentration photovoltaic module  2  of a first embodiment of the invention. The concentration photovoltaic module  2  includes a substrate  21 , a first electrode  22 , a second electrode  23 , a solar cell  24 , a plurality of electrical connecting elements  25 , a frame  26 , an optical element  27 , a connecting layer  28  and a medium  29 . 
         [0021]    The substrate  21  may be made of ceramic, sapphire, aluminum nitride (AlN), silicon carbide (SiC), beryllium oxide (BeO) or other materials. The first electrode  22  and the second electrode  23  are formed in different predetermined positions of the substrate  21  and electrically connected to the positive electrode  241  and the negative electrode  242  of the solar cell  24  to have positive polarity and negative polarity, respectively. The first electrode  22  and the second electrode  23  are respectively connected to the conductive wires for transmitting electrical energy from the solar cell to an electrical device electrically connected to the other ends of the conductive wires, and providing electrical energy for the electrical device to operate. Alternatively, the first electrode  22  can be a negative polarity and the second electrode  23  can be a positive polarity which is opposite to the first electrode  22 . 
         [0022]    The solar cell  24  includes a positive electrode  241  and a negative electrode  242 . The solar cell  24  is a photoelectric device having a function of transforming the photovoltaic energy into electrical energy. The assembly and theory of the solar cell  24  are well-known and thus not described. The solar cell  24  is connected to the first electrode  22  by tin soldering or conductive adhesive. The first electrode  22  is electrically connected to the positive electrode  241  of the solar cell  24 , and the second electrode  23  is electrically connected to the negative electrode  242  of the solar cell  24  by a plurality of electrical connecting elements  25 . The first electrode  22  and the second electrode  23  have opposite polarities, wherein the first electrode  22  and the electrode  241  of the solar cell  24  are of the same polarity, and the second electrode  23  and the electrode  242  of the solar cell  24  are of the same polarity. 
         [0023]    The frame  26  is substantially rectangular in the first embodiment, but may be round, polygonal or shaped in other geometric configurations in other embodiments. The frame  26  is made of a ceramic material and includes a cavity  261 , and an internal annular groove  262  with predetermined depth is provided on the upper part of the frame  26 , wherein the frame  26  straddles on the substrate  21  for allowing the solar cell to be disposed therein. 
         [0024]    The optical element  27  may be a transparent protect cover, a polymer, a reflecting mirror, a lens or other optical elements with high transparency. The optical element  27  is installed in the annular groove  262  to package the cavity  261  and prevent the solar cell  24  in the cavity  261  from contacting outside environmental factors (e.g. surrounding vapor, corrosive and dust). Referring to  FIG. 6 , the second embodiment of the invention is shown. In the second embodiment, the framer  26  doesn&#39;t have the annular groove  262 , and the optical element  27  is directly installed on the frame  26 . 
         [0025]    The connecting layer  28  is disposed under the substrate  21  via coating or printing. In the first embodiment, the connecting layer  28  may be silver paste and connected to a heat dissipating seat to conduct the heat from the concentration photovoltaic module  2  to the heat dissipating seat. 
         [0026]    The medium  29  may be a transparent adhesive or a polymer material with high transmittance and good insulating property. The medium  29  is chosen to have a refractive index close to the optical element  27 . Empty space of the cavity  261  is filled with the medium  29 . The medium  29  tightly adheres to the optical element  27  and covers the solar cell  24  to provide isolation and protection functions. Furthermore, the medium  29  tightly adheres to the optical element  27 . As a result, more light can pass through the medium  29  and the optical element  27  when the refractive indexes of the medium  29  and the optical element  27  are close to each other. Thus, the efficiency of absorbing solar energy can be increased. 
         [0027]    Referring to  FIG. 7 , a sectional view of a concentration photovoltaic module of a third embodiment of the invention is shown. In this embodiment, the cavity  261  inside is not provided with any medium, and air inside the cavity  261  is a medium for solar conduction. Referring to  FIG. 8 , a fourth embodiment of the invention is shown. In this embodiment, the cavity  261  is filled with a proper quantity of a medium for packaging the solar cell  24 . 
         [0028]    For above description, the invention discloses the concentration photovoltaic module  2  including the frame  26  disposed on the substrate  21  and the optical element  27  disposed on the frame  26 . The solar cell  24  is disposed in the cavity  261  which includes the framer  26  and the optical element  27 , and then a package process is performed inside the cavity  261 . Furthermore, in above design, the solar cell  24  can be effectively protected by the frame  26  and the optical element  27  from outside environment (e.g. surrounding vapor, corrosives and dust) and the profile of the concentration photovoltaic module is improved. The invention can control a height of the frame  26  to adjust a distance and a parallelism parameter between the optical  27  and the solar cell  24  to improve the solar energy absorption efficiency of the solar cell  24 . 
         [0029]    While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.