JP2010205757A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar battery module for enabling an appropriate material to be selected and an appropriate thickness to be selected and preventing warpage from occurring easily. <P>SOLUTION: The solar battery module 1 including a solar battery cell 4, a sealing section 3, a transparent plate 2, and a reflection plate 5 satisfies a formula (1), where E<SB>1</SB>in the transparent plate 2 is a Young's modulus, I<SB>1</SB>is a geometrical moment of inertia, α<SB>1</SB>is E<SB>2</SB>at a coefficient-of-linear expansion sealing section 3 (Young's modulus), I<SB>2</SB>is a geometrical moment of inertia, α<SB>2</SB>is E<SB>3</SB>at a coefficient-of-linear-expansion reflection plate 5 (Young's modulus), I<SB>3</SB>is a geometrical moment of inertia, and α<SB>3</SB>is a coefficient of linear expansion. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a concentrating solar cell module provided with a reflector.

  Conventionally, there is JP-A-2001-119054 as a technology in such a field. The solar cell module described in this publication includes a plurality of double-sided light incident type solar cells that are spaced apart from each other in a transparent member (sealing portion) made of an ethylene-vinyl acetate copolymer (EVA). I have. The sealing portion is provided with a glass transparent plate located on the front surface side, and an aluminum or stainless steel substrate (reflecting plate) located on the back surface side. Sunlight incident from the transparent plate of the module is directly incident on the surface side of the solar battery cell. Furthermore, the sunlight which passed between adjacent photovoltaic cells and reached | attained the board | substrate is incident as indirect light on the surface side of a photovoltaic cell. The solar cell module having such a configuration can effectively use light incident between adjacent solar cells, and can improve power generation efficiency.

JP 2001-119054 A

  Various materials and thicknesses can be used for the transparent member (sealing portion), the transparent plate, and the substrate (reflecting plate) in the above-described conventional solar cell module. However, when manufacturing solar cell modules that are less likely to warp not only due to temperature changes during manufacturing but also due to temperature changes in the environment of use, it is more rigid than necessary when selecting the material and thickness of each component. If a material with a high thickness is used or if the thickness is increased more than necessary, warpage is unlikely to occur, but there is a problem that the cost and weight of the solar cell module are increased.

  It is an object of the present invention to provide a solar cell module that allows appropriate material selection and thickness selection and is unlikely to cause warpage.

但し、
透明板におけるＥ_１…ヤング率、Ｉ_１…断面二次モーメント、α_１…線膨脹係数
封止部におけるＥ_２…ヤング率、Ｉ_２…断面二次モーメント、α_２…線膨脹係数
反射板におけるＥ_３…ヤング率、Ｉ_３…断面二次モーメント、α_３…線膨脹係数 The present invention provides a sealing portion in which solar cells are enclosed, a transparent plate that is fixed to the sealing portion and allows sunlight to enter, and is disposed to face the transparent plate and is fixed to the sealing portion. A solar cell module comprising a reflector for reflecting sunlight toward the solar cell,
The solar cell module characterized by satisfying the following formula (1).

However,
E ₁ in the transparent plate: Young's modulus, I ₁ ... secondary moment of section, α ₁ ... E ₂ in the linear expansion coefficient sealing portion ... Young's modulus, I ₂ ... secondary moment of section, α ₂ ... in the linear expansion coefficient reflector E ₃ ... Young's modulus, I ₃ ... Sectional moment of inertia, α ₃ ... Linear expansion coefficient

  In this invention, when manufacturing a solar cell module that is unlikely to be warped by heat, a material having rigidity higher than necessary is used in selecting a material and thickness of a sealing portion, a transparent plate, and a reflector. Therefore, since it is not necessary to increase the thickness more than necessary, the cost increase and weight increase of the solar cell module can be suppressed.

Further, it is preferable that the thickness of the reflector is uniform.
By adopting such a configuration, the solar cell module cracks, especially the solar cell cracks, can be suppressed without causing a part of the reflector plate to suddenly become hot or cold due to temperature fluctuations in the outside air. can do.

  According to the present invention, it is possible to select an appropriate material and thickness, and to prevent the solar cell module from warping.

It is sectional drawing which shows one Embodiment of the solar cell module which concerns on this invention. It is sectional drawing which shows the curvature state of a solar cell module with a broken line. 5 is a graph showing the relationship between ΔZ / L and S.

  Hereinafter, preferred embodiments of a solar cell module according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the concentrating solar cell module 1 is installed on the roof of an automobile, the roof of a house, etc., and enables efficient solar power generation. The solar cell module 1 includes a transparent plate 2 having a substantially uniform thickness that allows sunlight to enter. The transparent plate 2 includes soda glass, borosilicate glass, quartz glass, polycarbonate, acrylic resin, etc. Of these, soda glass is preferable from the viewpoint of strength, heat resistance, long-term reliability, and cost.

  Solar cells 4 arranged in a matrix are enclosed in a sealing portion 3 fixed to the transparent plate 2. As a sealing material used for the sealing portion 3, ethylene-vinyl acetate is used. A polymer (EVA) is preferred.

  The solar cell 4 includes a type that captures sunlight on both sides and a type that captures sunlight on one side. In this embodiment, a double-sided light-receiving solar cell is used. Cell types include single crystal Si cells, polycrystalline Si cells, thin film Si cells, III-V cells, compound cells, and organic cells.

  A reflective plate 5 having a mountain-shaped cross section is fixed to the back surface side of the sealing portion 3 so as to face the transparent plate 2 disposed on the front surface side of the sealing portion 3. The reflector 5 having a substantially uniform thickness has an uneven shape, and from the viewpoints of shape shaping by press, long-term reliability, and cost, even if it is a metal plate, a plastic plate or a glass plate, these materials are used as a base material. In addition, silver or aluminum deposited on the surface as a reflective film may be used.

  By using the reflecting plate 5, the sunlight that has passed through the adjacent solar cells 4 and reached the reflecting plate 5 is reflected by the reflecting surface 5 a of the reflecting plate 5, and then on the back surface side of the solar cells 4. It can be made incident. Thereby, high output electricity can be generated in the solar cell 4 by the sunlight incident on the front surface side of the solar cell 4 and the sunlight incident on the back surface side of the solar cell 4.

但し、
透明板２におけるＥ_１…ヤング率、Ｉ_１…断面二次モーメント、α_１…線膨脹係数
封止部３におけるＥ_２…ヤング率、Ｉ_２…断面二次モーメント、α_２…線膨脹係数
反射板５におけるＥ_３…ヤング率、Ｉ_３…断面二次モーメント、α_３…線膨脹係数

但し、
太陽電池モジュール１の最も厚い位置におけるａ…透明板２の厚み、ｂ…封止部３の厚み、ｃ…反射板５の厚み Various materials and thicknesses can be used for the transparent plate 2, the sealing portion 3, and the reflection plate 5 in the solar cell module 1 described above. However, referring to FIG. 2, in manufacturing the solar cell module 1 that is not easily warped not only by a temperature change during manufacturing but also by a temperature change in a use environment, the transparent plate 2, the sealing portion 3, In selecting the material and thickness of the reflector 5, the solar cell module 1 is designed and examined based on the following formula (1).

However,
E ₁ in the transparent plate 2 ... Young's modulus, I ₁ ... secondary moment of section, α ₁ ... E ₂ in the linear expansion coefficient sealing portion 3 ... Young's modulus, I ₂ ... secondary moment of section, α ₂ ... reflection of linear expansion coefficient E ₃ in the plate 5 ... Young's modulus, I ₃ ... secondary moment of section, α ₃ ... linear expansion coefficient

However,
A at the thickest position of the solar cell module 1... Thickness of the transparent plate 2, b...

  Formula (1) is shown by the ratio of the stretching force (numerator) of the reflector 5 to the stretching force (denominator) of the entire solar cell module 1. The expansion / contraction force is a value obtained by multiplying the rigidity (E × I) of each member 2, 3, 5 with respect to the neutral axis of the warp by the linear expansion coefficient (α).

  Further, the denominator of the formula (1) assumes that there is slippage between the interface between the transparent plate 2 and the sealing portion 3 and the interface between the sealing portion 3 and the reflecting plate 5, and then each member 2, 3, 5. Indicates how much force is going to expand and contract.

  When the formula (1) is not satisfied, ΔZ / L> 0.01 (the total length L before the warp of the solar cell module 1, the warp amount ΔZ, the warp rate ΔZ / L). Causes a drop. This is because the expansion / contraction force of the reflecting plate 5 is smaller than that of the entire solar cell module 1, which causes expansion / contraction resistance of the transparent plate 2 and the sealing portion 3, and causes large warpage of the solar cell module 1.

  On the other hand, when the expression (1) is satisfied, ΔZ / L ≦ 0.01 is satisfied, and the balance between the expansion / contraction force of the transparent plate 2 or the sealing portion 3 and the expansion / contraction force of the reflection plate 5 is improved, and warpage occurs. It is hard to do.

  By using the above-described formula, it is easy to evaluate the material and thickness of the transparent plate 2, the sealing portion 3, and the reflection plate 5 at the design stage and the examination stage, so that no excessive prototyping is required. In particular, this formula facilitates the examination of the thickness of the reflector 5 rich in materials.

  When the material and thickness of the reflecting plate 5 are optimized, the stretching force of the reflecting plate 5 with respect to the entire solar cell module 1 can be increased. As a result, the warpage rate of the solar cell module 1 can be greatly reduced, and the molding accuracy during manufacturing can be improved.

  By suppressing the warpage of the solar battery module 1, it is possible to prevent the solar battery cells 4 from cracking and to reduce the defect occurrence rate during manufacturing.

  By suppressing the warpage of the solar cell module 1, the light reflected by the reflector 5 can be accurately incident on the solar cell 4, and the light collection efficiency as in the optical design can be maintained for a long time. .

  In selecting the material and thickness of the sealing portion 2, the transparent plate 3, and the reflecting plate 5, it is not necessary to use a material having rigidity higher than necessary, and it is not necessary to increase the thickness more than necessary. The cost increase and weight increase of the battery module 1 can be suppressed. By suppressing the increase in weight, the weight can be reduced, and the reinforcement of the roof of the automobile and the roof of the house can be suppressed to a minimum, and workability at the time of construction is improved.

  Since the thin plate of the reflector 5 can be optimized, an increase in the temperature of the entire solar cell module 1 can be suppressed as the heat capacity of the reflector 5 is reduced. For example, when the calorific value when the temperature of the solar cell module 1 is 20 ° C. is 100, when the temperature of the solar cell module 1 rises to 70 ° C. in summer, the calorific value is reduced by 10 to 20%. It is important to reduce the heat capacity of the reflector 5.

  Moreover, the thickness of the reflecting plate 5 is uniform. When such a configuration is adopted, a part of the reflector 5 does not suddenly become high or low due to temperature fluctuations of the outside air, and the solar cell module 1 is cracked, in particular, the solar cell 4. Cracking can be suppressed.

Next, the basis of the formula (1) will be described.
A material and thickness suitable for the solar cell module 1 are selected, and the numerical values in (1) to (10) in the following table are substituted into the above formula, and (1) to (10) in the following table. The values of S as shown in FIG. Further, using structural analysis software generally used in the construction and automobile industries, the numerical values in (1) to (10) in the following table are substituted, and (1) to (10 in the following table) The value of ΔZ / L as shown in FIG. Each result is plotted as points (1) to (10) on the graph as shown in FIG.

  From this calculation result, the curve P can be drawn on the graph of FIG. 3 by the graph creation software.

  When ΔZ / L ≦ 0.01, it has been found from experience that the balance between the stretching force of the transparent plate 2 or the sealing portion 3 and the stretching force of the reflecting plate 5 is improved, and warpage is unlikely to occur. Therefore, the value [K] (0.460) of S when ΔZ / L = 0.01 was obtained from the graph, and based on this, S> 0.46 was derived.

  In the table below, A, C, D, E, and Examples are examples in which materials and thicknesses that satisfy Equation (1) are selected, and B is selected as materials and thicknesses that do not satisfy Equation (1). In this example, a change in temperature from 145 ° C. to 20 ° C. was given at the time of manufacture, and after actually making them, ΔZ / L was measured and verified.

  As can be seen from FIG. 3, the experimental value B that does not satisfy the equation (1) is ΔZ / L> 0.01, and the experimental values A, C, D, and E that satisfy the equation (1) are as follows: It was confirmed from the experimental results that ΔZ / L ≦ 0.01.

  Therefore, it turns out that there is a deep relationship between ΔZ / L and S, and based on the formula (1), it can be said that a solar cell module with less warpage can be predicted.

  Therefore, for example, when a material to be used is specified, when manufacturing a solar cell module with less warpage, the thickness can be easily examined while considering weight reduction and high rigidity.

  It goes without saying that the present invention is not limited to the embodiment described above. The present invention is applicable even to a solar cell module that allows light from the reflecting plate 5 to enter. Moreover, the solar cell module which has arrange | positioned the translucent reflector on the front surface and the back surface of the sealing part 3 may be sufficient. The reflecting plate 5 may have a concavo-convex cross-sectional mountain shape, corrugated shape, or flat plate shape. Further, the present invention can be applied regardless of the size of the unevenness of the reflector 5.

  DESCRIPTION OF SYMBOLS 1 ... Solar cell module, 2 ... Transparent plate, 3 ... Sealing part, 4 ... Solar cell, 5 ... Reflector.

Claims (2)

A sealing part in which solar cells are sealed, a transparent plate fixed to the sealing part and allowing sunlight to enter, and disposed to face the transparent plate and fixed to the sealing part, A solar cell module comprising a reflector for reflecting sunlight toward the solar cell,
The solar cell module characterized by satisfying the following formula (1).

However,
E ₁ in the transparent plate: Young's modulus, I ₁ ... secondary moment of section, α ₁ ... E ₂ in the linear expansion coefficient sealing portion ... Young's modulus, I ₂ ... secondary moment of section, α ₂ ... in the linear expansion coefficient reflector E ₃ ... Young's modulus, I ₃ ... Sectional moment of inertia, α ₃ ... Linear expansion coefficient   The solar cell module according to claim 1, wherein the reflector has a uniform thickness.

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