JP2006128329A - Double-side light-receiving solar cell module and solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-side light-receiving solar cell having a single-glass module structure improving dampproofness and reducing the deterioration of performance. <P>SOLUTION: In the double-side light-receiving solar cell module, a protective material on at least the rear side of a solar cell module is formed by evaporating and coating a cyclic olefin copolymer on the surface of a film composed of a polyethylene terephthalate (PET). In the solar cell, the double-side light-receiving solar cell module is installed on an inclined frame or installed vertically and a power is generated. The resistance to humidity is improved by mounting a high moisture-resistant transparent resin sheet, and a high moisture-resistant transparent resin back sheet can be realized. A time up to the deterioration of the performance can be elongated largely. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a double-sided light-receiving solar cell module that generates power not only from the front side but also from the back side, and more particularly, a slant that enables light reception and power generation at the back side by using a transparent resin sheet as a protective material on one side. The present invention relates to a double-sided light receiving solar cell module and a solar cell installed on a gantry.

  Conventionally, a solar cell with a single-sided light-receiving surface has been the mainstream, and a backsheet on the back surface generally uses a non-transparent resin such as white in order to reflect light that has passed through the solar cell and increase conversion efficiency. Moreover, in order to prevent deterioration of a solar cell, the method of laminating | stacking aluminum foil in the back seat | sheet of a back surface, and giving high moisture resistance is taken. Further, in the field of building material integrated type, when installing a solar cell in a curtain wall, it is common to cover both the front and back surfaces with glass.

In the double-sided light receiving solar cell, as described in [Patent Document 1], solar cells are arranged in a matrix and electrically connected in series by a connecting member made of a metal thin plate such as a copper thin plate, There is a solar cell module sealed between a front surface member and a back surface member by a light-transmitting and insulating sealing material such as EVA. And, as the front member and the back member, glass having an outer dimension of 1300 mm × 875 mm is used, the module structure allows light incidence from both sides, and the back member is not limited to glass, and a light-transmitting plastic material is used. It is described that when a translucent plastic material is used, a material having a water vapor transmission rate of 20 g / m ² · day or less is preferable.

JP 2000-101122 A

  Since the double-sided light-receiving solar cell generates power not only from the front surface but also from the back surface, it is necessary to use a transparent protective material for both the front and back surfaces. The double glass module structure using the tempered glass that has been used in conventional single-sided light-receiving solar cells as a protective material for the front and back surfaces is an effective structure for constituting a double-sided light-receiving solar cell module. In particular, when applied to a vertically installed double-sided light-receiving solar cell in which the difference in power generation from the single-sided light-receiving solar cell is the largest, it is suitable for protecting the solar cell against falling objects such as a bag.

  However, the double glass module structure has a heavy mass because it uses at least two pieces of glass, and is disadvantageous in terms of work in transportation and installation of the solar cell module. In addition, in the manufacturing process, the double glass module structure has a glass overlapping work as compared with the single glass module structure, and in the lamination work for sealing the solar cells with the sealing material, the sealing material is dissolved. There is a high possibility that the flow of cells and the generation of bubbles will occur, and the productivity is inferior.

  For this reason, it can be considered that the double-sided light-receiving solar cell has a single glass module structure. In this case, in order to fully exhibit the function, the double-sided light-receiving solar cell needs to receive light even on the back surface, and a transparent highly transparent resin sheet is used for the back sheet. However, conventional resin sheets such as transparent fluororesin films are inferior in moisture resistance and have a problem of deterioration in the performance of solar cells due to moisture absorption.

  An object of the present invention is to provide a double-sided light-receiving solar cell having a single glass module structure with improved moisture resistance and less performance deterioration.

  Another object of the present invention is to provide a double-sided light-receiving solar cell with improved humidity resistance and less performance deterioration.

  In order to achieve the above object, the double-sided light-receiving solar cell of the present invention has one or both sides protected with a transparent resin sheet having high moisture resistance. A transparent resin sheet having excellent transparency and high moisture resistance is a polyethylene terephthalate film coated with a cyclic olefin copolymer. Moreover, the double-sided light-receiving solar cell module using a transparent resin sheet is installed on an inclined frame.

  According to the present invention, by providing a highly moisture-resistant transparent resin sheet, moisture resistance can be improved and a highly moisture-resistant transparent resin back sheet can be realized. In addition, the time to performance degradation can be greatly extended.

  In the double-sided light-receiving solar cell module, the protective material is required to be transparent in order to receive light from the front surface and the back surface. In addition, it is known that when the double-sided light receiving solar cell module is installed vertically, the annual power generation amount is about 1.3 times larger than that of the single-sided light receiving solar cell module.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view showing the structure of a solar battery cell of this example, FIG. 2 is a plan view showing grid-like electrodes of the solar battery cell, and FIG. 3 is a single glass with a transparent back sheet applied on one side. It is a longitudinal cross-sectional view of the double-sided light receiving solar cell having a module structure.

As shown in FIG. 1, in the solar cell 10 of this example, an n ⁺ layer 2 by phosphorus diffusion is formed on the front surface of the silicon substrate 1 and a p ⁺ layer 3 by boron diffusion is formed on the back surface. . The n ⁺ layer 2 and the p layer of the silicon substrate 1 form a pn junction, and the p ⁺ layer 3 on the back surface side forms a BSF. A silicon oxide film (SiO ₂ ) 4 is formed on the n ⁺ layer 2 and the p ⁺ layer 3. In the diffusion substrate having the n ⁺ pp ⁺ BSF structure, a front electrode 5 which is a (−) electrode on the front surface and a back electrode 6 which is a (+) electrode are formed on the back surface.

  As shown in FIG. 2, the grid electrode of the solar battery cell includes a bus bar electrode 8 and a finger electrode 9, and a narrow finger electrode 9 extends from the wide bus bar electrode 8.

  As shown in FIG. 3, the solar cell module has solar cells 10 sealed with a sealing material 12, tempered glass 11 is provided as a protective material on the surface of the sealing material 12, and protection is provided on the back surface. A high moisture resistant transparent resin sheet composed of a resin base material 13 and a water repellent layer 14 is provided as a material. A polyethylene terephthalate (PET) film is used as the resin base material 13, and a cyclic olefin copolymer is deposited on the surface as a water repellent layer 14 to form a highly moisture-resistant transparent resin sheet.

  Here, the cyclic olefin copolymer used for the water-repellent layer 14 has a glass transition temperature of 130 to 130 in order to prevent damage caused by heating performed in the lamination process when the solar battery cell 10 is sealed with the sealing material 12. The one that is 150 ° C is selected. Further, it is desirable to set the light transmittance to be 90% or more. If the coating is too thick, the resin base material 13 having a different linear expansion coefficient is deformed due to thermal expansion during lamination. Therefore, the thickness of the coating is preferably about 3 μm so that the thermal deformation mainly occurs on the resin base material 13 side. . Further, if the difference in thickness distribution in the coating surface is large, cracks may occur during thermal deformation, and it is preferable to coat uniformly.

  The polyethylene terephthalate used for the resin base material 13 is preferably as low as possible in moisture permeability, but the moisture permeability is limited due to the properties of the material, and it is preferable to use one having a light transmittance of 90% or more. The base material of the back sheet has a thickness of 100 μm or more so that the outer shape of the back sheet is not impaired when the sealing material is dissolved during lamination.

  With this configuration, it is possible to receive incident light 15 from the tempered glass 11 that is the protective material on the front surface side and incident light 16 from the high moisture-resistant transparent resin sheet that is the protective material on the back surface side, thereby realizing a double-sided light receiving solar cell. In addition, damage caused by falling objects such as falling when the solar cell module is installed vertically can be prevented, and protection from falling objects can be performed.

  When it is possible to use the tempered glass 11 without providing the tempered glass 11 on the surface side, a highly moisture-resistant transparent resin sheet composed of the resin base material 13 and the water repellent layer 14 may be provided as a protective material on the surface side. Also in this case, a polyethylene terephthalate (PET) film is used as the resin base material 13, and a cyclic olefin copolymer is vapor-deposited as a water repellent layer 14 on the surface to form a highly moisture-resistant transparent resin sheet.

  A solar cell module 20 provided with a tempered glass 11 on the front surface side and provided with the high moisture-resistant transparent resin sheet of this embodiment as a protective material on the back surface side, and a tempered glass 11 provided on the front surface side, and a conventional protective material on the back side. A solar cell module 21 provided with a transparent fluororesin sheet was manufactured, and a comparative test was performed at high temperature and high humidity. In this test, a thermostat was used, the temperature was set to 85 ° C., the humidity was set to 85%, the solar cell modules 20 and 21 were inserted, and the relationship between the passage of time and the electrical performance was measured for each of the solar cell modules 20 and 21.

  4 and 5 show the test results. FIG. 4 shows the output change characteristic on the front side, and FIG. 5 shows the output change characteristic on the back side. Comparing the elapsed time when the electrical performance decreased to 95% of the initial value, as shown in FIG. 4, the solar cell module 20 is about 5.8 times longer on the surface side, as shown in FIG. In addition, the solar cell module 20 was about 7.1 times longer on the back side.

  Thus, by providing the highly moisture-resistant transparent resin sheet of this example, moisture resistance can be improved and a highly moisture-resistant transparent resin back sheet can be realized. In addition, the time to performance degradation can be greatly extended.

  The double-sided light-receiving solar cell may be installed vertically, or may be installed on an inclined frame in the same manner as the single-sided light-receiving solar cell. Since the double-sided solar cell generates power even when it receives light from the back surface, for example, it is provided with an inclination angle of 30 ° with respect to the ground to generate power by receiving reflected light and scattered light from the back surface. A larger amount of power generation than the light receiving solar cell can be obtained. It is possible to install a double-sided light receiving solar cell having a double glass module structure on an inclined pedestal, but the inclined pedestal becomes larger due to its heavy weight. The double-sided light receiving solar cell with a single glass module structure of the present embodiment can be reduced in weight. Therefore, in particular, when constructing a large-capacity solar power generation system by laying the solar cell module on a large area of land, the tilt frame is made small. As a result, since many solar cell modules can be installed, the amount of power generation can be increased. Moreover, construction workability and productivity can be improved.

  Compared to double-sided solar cells with a double glass module structure used for vertical installation, the single glass module using a transparent resin sheet instead of glass as the protective material on one side does not impair the power generation function due to light reception from the back side. In addition to being lightweight, it can be manufactured at low cost, and greatly expands the application of the double-sided light receiving solar cell module to a photovoltaic power generation system using an inclined frame installation method. In addition, the application range of high-efficiency double-sided solar cell modules has increased, and it has become possible to realize a large-scale photovoltaic power generation system that prevents natural destruction. By obtaining natural energy that does not generate carbon dioxide, It can greatly contribute to environmental protection.

The longitudinal cross-sectional view which shows the structure of the photovoltaic cell which is one Example of this invention. The top view which shows the grid-like electrode of a photovoltaic cell. The longitudinal cross-sectional view of the double-sided light reception type solar cell of the single glass module structure which applied the transparent backsheet to the single side | surface. The figure which shows the output change of the surface side by the test of high temperature high humidity. The figure which shows the output change of the back side by the test of high temperature high humidity.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Solar cell, 11 ... Tempered glass, 12 ... Sealing material, 13 ... Resin base material, 14 ... Water-repellent layer, 15 ... Front surface incident light, 16 ... Back surface incident light.

Claims (5)

  A double-sided light-receiving solar cell module in which a protective material on at least the back side of the solar cell module is formed of a highly moisture-resistant transparent resin sheet by depositing a water-repellent layer on the surface of a resin base material. A double-sided solar cell module in which a protective material on at least the back side of the solar cell module is formed by vapor-depositing a cyclic olefin copolymer on the surface of a polyethylene terephthalate (PET) film.   The double-sided solar cell module according to claim 1 or 2, wherein tempered glass is provided as a protective material on the surface side of the solar cell module.   The solar cell which installs the double-sided light reception type solar cell module in any one of Claim 1 to 3 in an inclination mount frame, and generates electric power. A solar cell for generating power by vertically installing the double-sided light-receiving solar cell module according to claim 1.

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