JP2006286789A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-sided light incident solar battery module capable of improving output by increasing an incident light amount into solar battery cells. <P>SOLUTION: The double-sided light incident solar battery module 10 is configured in such a way that a plurality of double-sided light incident solar battery cells 1 are arranged so as to be spaced between an optical transmissive front surface member 4 an optical transmissive rear surface member 5 and the cells 1 are sealed with a filling material. In this module 10, reflection layers 9A, 9B and 9C for reflecting a light are each, closer the rear surface side than the solar battery cells 1, provided from a region not opposing the solar battery cells 1 to a position opposing the external edge of the solar battery cells 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solar battery module including a plurality of double-sided light incident solar cells.

  Solar cell modules with multiple solar cells have a single-sided light-incident type that uses the incident light only from the front side of the solar battery cell for power generation, covered with a film that does not transmit light, etc., and transparent on the back surface There is a double-sided light incident type in which incident light from both the front and back surfaces of a solar battery cell is used for power generation using a simple film or glass.

  When both types of solar cell modules are installed under the same conditions and their electromotive force characteristics are examined, the double-sided light incident type solar cell module is about 5% to 10% compared to the single-sided light incident type solar cell module. Results in improved output.

  A conventional double-sided light incident type solar cell module is a state in which a plurality of adjacent solar cells are electrically connected to each other by a connection member made of a conductive material such as copper foil, with a predetermined interval between them. And embedded in a layer of filler such as EVA (ethylene vinyl acetate).

  For example, a surface member made of a light-transmitting tempered glass plate is provided on the front surface side of the filler, and a light-transmitting film or a light-transmitting tempered glass plate is formed on the back surface side. A back member is provided.

  By the way, in the conventional double-sided light incident type solar cell module, the light incident on the region where the solar cell is present can be incident on the solar cell and contribute to power generation, but the solar cell does not have the solar cell. Most of the light incident on the region between the cells passes through the back member without entering the solar cell. Therefore, the conventional double-sided light incident type solar cell module has a problem that the light incident on the region between the adjacent solar cells cannot be effectively used.

Therefore, the applicant has disclosed a solar cell module in which a reflective member that selectively reflects light is selectively provided corresponding to a region between adjacent solar cells. Thereby, the light incident between the adjacent solar cells can be reflected by the light reflecting member and can enter the solar cells. Thereby, the light which entered between the adjacent photovoltaic cells can be contributed to electric power generation, and it becomes possible to aim at the improvement of electric power generation efficiency (for example, refer patent document 1).
Japanese Patent Laid-Open No. 11-298029

  However, in such a structure (a structure in which a reflecting member that reflects light is provided corresponding to a region between adjacent solar cells), high alignment accuracy is required, and the position is slightly shifted. However, there is a problem that the light reflecting member cannot be effectively used. In addition, light entering the front surface member from an oblique angle to a shallow angle does not strike the reflecting member, and almost passes through the back surface member as it is. For this reason, the light from the strong surface member side cannot be used effectively, and sufficient output cannot be obtained.

  The present invention has been made to solve the related art, and an object of the present invention is to provide a solar cell module capable of improving the output by increasing the amount of light incident on the solar cell. And

  In the solar cell module of the present invention, a plurality of double-sided light-incident solar cells are arranged apart from each other between a light-transmitting front member and a light-transmitting back member, and sealed with a filler. A reflective layer that reflects light is provided across the position facing the outer edge of the solar cell from a region that does not oppose the solar cell from the back side of the solar cell. And

The solar battery module of the invention of claim 2 is the solar battery module according to the above invention, where D is the distance between the solar battery cell and the reflective layer, N0 is the refractive index of air, and N1 is the refractive index of the filler and surface member. The dimension L of the reflective layer at the portion facing the outer edge is L = D × tan θ1, where θ1 = sin ⁻¹ (N0 / N1).

  A solar cell module according to a third aspect of the present invention is characterized in that, in each of the above-described inventions, the reflective layer is provided on the surface of the back surface member on the solar cell side corresponding to the adjacent solar cells.

  According to a fourth aspect of the present invention, there is provided a solar cell module according to the above-mentioned invention, wherein the reflective layer is formed on the outer side of the outermost solar cell, and the portion corresponding to the outer side of the solar cell is a back surface solar cell. Is provided on the opposite surface, and the portion facing the outer edge of the solar cell is provided on the solar cell side surface of the back member.

  According to the present invention, a solar cell in which a plurality of double-sided light incident solar cells are arranged apart from each other between a light-transmitting front surface member and a light-transmitting back surface member and sealed with a filler. In the battery module, since the reflective layer that reflects light is provided across the position facing the outer edge portion of the solar battery cell from the area that does not face the solar battery cell from the back surface side, the back member side Light that is incident obliquely between solar cells or outside the solar cells can be reflected by the reflective layer and can enter the solar cells while suppressing blocking of light from the surface member. Light from the side can be used effectively and sufficient output can be obtained.

In particular, when the distance between the solar battery cell and the reflective layer is D, the refractive index of air is N0, and the refractive index of the filler and the surface member is N1 as in the invention of claim 2, it faces the outer edge of the solar battery cell. The dimension L of the reflective layer of the part is L = D × tan θ1, where θ1 = sin ⁻¹ (N0 / N1). This makes it possible to reliably reflect light incident at a shallow angle between the solar cells on the reflective layer and enter the solar cells. Therefore, more sufficient output can be obtained.

  Further, as in the invention of claim 3, the reflective layer is provided on the solar cell side surface of the back surface member so as to correspond between the adjacent solar cells, so that the size of the portion facing the outer edge of the solar cell is measured. Can be minimized.

  Thereby, incident light from the front surface member side can be reliably captured by the reflection layer and used effectively, and the inconvenience of preventing light incidence from the back surface member side can be avoided as much as possible. Therefore, a more sufficient output can be obtained. In addition, regarding the solar cells between which light is most reflected, it is possible to provide an alignment tolerance by L = D × tan θ1 as in claim 2.

  Further, according to the fourth aspect of the invention, the reflective layer is formed on the outer surface of the outermost solar battery cell where the portion corresponding to the outer side of the solar battery cell is on the surface of the back member opposite to the solar battery cell. Since the portion facing the outer edge portion of the solar battery cell is provided on the surface of the back surface member on the solar cell side, the portion facing the outer edge portion of the solar battery cell has a shallow angle as in the above inventions. The incident light can be reflected, and in the portion outside the solar battery cell, the light incident from the solar battery cell can be reflected in the solar battery cell direction.

  As a result, the amount of light incident on the solar cell is increased, and the power generation efficiency is further increased, so that the output of the solar cell module can be increased.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 is a cross-sectional view of a solar cell module 10 according to an embodiment to which the present invention is applied, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is an exploded view of the solar cell module of FIG.

  In the figure, reference numeral 1 denotes a double-sided light incident type solar battery cell. In the present embodiment, a plurality of double-sided light incident type solar cells 1 are arranged apart from each other, and the adjacent solar cells 1, 1 are electrically connected by a connecting member 2 made of, for example, copper foil. It is connected to the. And the high output is obtained by electrically connecting the photovoltaic cells 1 in series with the connection member 2.

  The electrical output generated by the solar cell module 10 is taken out from the gap between the front surface member 4 and the back surface member 5 through a filler, which will be described later, by a power lead line (not shown) and connected to the terminals in the terminal box. Then, it is taken out by an electric cable (not shown).

  Moreover, the several photovoltaic cell 1 of the state connected by the said connection member 2 is sealed in the layer of the filler mentioned above. In this embodiment, EVA (ethylene vinyl acetate), which is a thermoplastic resin, is used as the filler, and this is hereinafter referred to as EVA layer 3.

  Further, a front surface member 4 is provided on one surface side (front surface side) of the EVA layer 3, and a back surface member 5 is provided on the other surface side (back surface side). Both the front member 4 and the back member 5 are made of a light-transmitting material, for example, white plate tempered glass. Then, a plurality of solar cells are sealed in the EVA layer 3 between the front surface member 4 and the back surface member 5, and these solar cells 10 are integrated by holding these outer peripheral edges with the frame body 7. Composed.

  Here, a reflective layer 9 that reflects light is provided on the back surface side of the solar battery cell 1 and from a region that does not face the solar battery cell 1 to a position that faces the outer edge of the solar battery cell 1. . In this embodiment, the reflective layer 9 is provided on the surface of the back surface member 5 on the solar battery cell 1 side, and is formed by printing (white printing) on the back surface member 5. The reflective layer 9 is printed on the inner surface of the back member 5 (on the surface on the solar cell 1 side) at the portion corresponding to the solar cells 1 and 1 (hereinafter referred to as the reflective layer 9A), and on the outermost side. On the outside of the solar battery cell 1 positioned, the outer surface of the back surface member 5 (on the surface opposite to the solar battery cell 1) in the portion outside the solar battery cell 1 (hereinafter referred to as the reflective layer 9C), In the part (henceforth the reflection layer 9B) which opposes the outer edge part of the photovoltaic cell 1, it forms by printing on the inner surface of the back surface member 5. FIG.

  The reflective layers 9A and 9B facing the outer edge of the solar battery cell 1 will be described with reference to FIGS. FIG. 4 is a diagram showing a path of light that enters the solar cell module 10 from the surface member 4 side. In determining the dimension L of the reflective layers 9A and 9B facing the outer edge of the solar battery cell 1, the dimensions are calculated based on a predetermined formula. First, the refractive index of air is N0 (actually N0 = 1.0), and the refractive indexes of the surface member 4 and the EVA layer 3 are N1 (in this embodiment, both the surface member 4 and the EVA layer 3 have a refractive index N1 = 1. 5), the light incident on the surface member 4 at an angle θ0 is refracted by the surface member 4 and the angle becomes θ1 as shown in FIG. When this relationship is expressed by an equation, N0 × sin θ0 = N1 × sin θ1, and θ1 in the equation is an angle of light incident between the solar cells 1 and outside the solar cells 1.

  Here, the light incident on the surface member 4 having the shallowest angle is light having an angle closest to an angle of 90 ° parallel to the surface member 4. That is, at 90 °, light parallel to the surface member 4 does not enter, so only light having an angle smaller than 90 ° enters. Therefore, if θ0 = 90 ° can be covered, the light incident at the shallowest angle can be handled.

Therefore, if θ0 = 90 ° is substituted into the above equation, since sinθ0 = 1, θ1 = sin ⁻¹ (N0 / N1). If the distance between the solar battery cell 1 and the reflective layer 9A is D, the dimension L of the portion facing the outer edge is expressed by L = D × tan θ1.

  Thus, by determining the dimension L of the portion facing the outer edge portion of the solar battery cell 1 based on the above formula, the refractive index of the surface member 4 and the EVA layer 3 to be used, and the solar battery cell 1 and Since the optimum dimension L can be determined according to the distance D between the reflective layers 9A, the dimension of the portion facing the outer edge of the solar battery cell 1 is minimized and at the shallowest angle. Light incident between the solar cells 1, 1 can be reflected by the reflective layer 9 </ b> A so as to be incident on the solar cells 1.

  Further, by providing the reflective layers 9A and 9B on the inner surface of the back member 5 as described above, the solar cell 1 has a smaller size than the reflective layer provided on the outer surface (the surface opposite to the solar cell 1). Light incident at a shallow angle between 1 can be captured.

  That is, when the reflective layers 9A and 9B are provided on the outer surface of the back member 5 (the surface opposite to the solar battery cell 1), the distance D between the solar battery cell 1 and the reflective layer 9A becomes longer. In order to reliably capture light incident at a shallow angle between 1 and 1, the dimension L of the portion of the reflective layers 9A and 9B facing the outer edge of the solar battery cell 1 becomes larger. Thus, when the dimension L of the reflective layers 9A and 9B facing the solar battery cell 1 is increased, the scattered light (light reflected on the roof or the like) or the solar battery module 10 is installed vertically. The incident light from the back member 5 side is significantly inhibited from entering the solar battery cell 1 from the back member 5 side.

  Thereby, the light incident from the back surface member 5 is blocked by the reflective layers 9A and 9B, and the amount of light incident on the solar battery cell 10 is reduced, which may cause a decrease in output.

  Therefore, by providing the reflective layers 9A and 9B on the inner surface of the back member 5, the light incident between the solar cells 1 and 1 at a shallow angle can be captured with a smaller size than the reflective layers 9A and 9B on the outer surface. It can be reflected and incident on the solar cell 1.

  Thus, incident light from the front surface member 4 to the solar cells 1 and 1 can also contribute to the generation of electromotive force without hindering the incidence of light from the back surface member 5 as much as possible. The amount of light incident on the solar cell module 10 is increased, the power generation efficiency is increased, and the output of the solar cell module 10 can be increased.

  On the other hand, on the outer side of the outermost solar cell 1, the reflective layer 9 </ b> C is formed on the outer surface of the back member 5 (surface opposite to the solar cell 1) outside the solar cell 1. Thereby, it is possible to reflect the light incident from the solar battery cell 1 in the direction of the solar battery cell 1.

  As described above, by providing the reflective layer 9, a part of the light from the back surface member 5 is blocked, but light from the stronger surface member 4 side is incident from the back surface member 5 side of the solar battery cell 1. It is possible to increase the output. Further, by determining the dimension L of the reflective layers 9A and 9B facing the solar battery cell 1 based on the above formula, it is possible to minimize light blocking from the back member 5 side.

  In general, the amount of light incident on the solar cell 1 is increased, the power generation efficiency is increased, and the output of the solar cell module 10 can be increased.

  On the other hand, FIG. 5 is a sectional view showing an example of the double-sided light incident type solar battery cell 1. In FIG. 5, reference numeral 11 denotes an n-type crystalline silicon substrate made of a crystalline semiconductor such as single crystal silicon or polycrystalline silicon. On one main surface (front surface) of the crystalline silicon substrate 11, an i-type amorphous silicon layer 12 and a p-type amorphous silicon layer 13 are laminated in this order. A comb-shaped collector electrode 15 made of conductive conductive film (TCO) 14 and Ag is formed. On the other main surface (back surface) of the crystalline silicon substrate 11, an i-type amorphous silicon layer 16 and an n-type amorphous silicon layer 17 are laminated in this order. A comb-shaped collector electrode 19 made of conductive conductive film (TCO) 18 and Ag is formed.

  When manufacturing such a solar cell module 10, as shown in FIG. 3, the surface member 3, the EVA sheet 3 a to be the EVA layer 3, and a plurality of double-sided light incident type solar cells connected by the connection member 2. The battery cell 1, the EVA sheet 3b to be the EVA layer 3, the back surface member 5 printed with the reflection layers 9A, 9B, and 9C and the solar cells 1 are aligned and stacked, and these are thermocompression-bonded. To do. Thereby, after EVA sheet | seat 3a, 3b is gelatinized, the predetermined EVA layer 3 is comprised and integrated. And the solar cell module 10 is manufactured by hold | maintaining these outer periphery with the said frame 7. FIG. At this time, even if the back surface member 5 and each solar battery cell 1 are slightly misaligned, a portion facing the outer edge of the solar battery cell is provided as described above, that is, an alignment tolerance of the dimension L is provided. By providing it, it is possible to avoid the disadvantage that the output is remarkably lowered.

  In this embodiment, white plate tempered glass is used as the front member 4 and the back member 5, but a light transmissive film may be used for the back member. Further, the present invention is effective even when the reflective layer 9C is printed on the inner surface of the back member 5 (surface on the solar battery cell 1 side).

  Further, as described above, the outer peripheral edges of the front surface member 4, the back surface member 5, and the EVA layer 3 integrated by the thermocompression bonding process are held by the frame body 7. The invention may be applied. In the case where the frame is not attached, it is possible to capture light reflected on the solar cell module 10 from the lateral surface by the reflective layer 9C, reflect it, and enter the solar cell 1. Similarly, the amount of incident light on the solar cells 1 increases, the power generation efficiency increases, and the output of the solar cell module 10 can be increased.

  Furthermore, although the reflective layer 9 is provided by printing on the back member 5, the reflective layer 9 of the present invention is not limited to the one printed on the back member 5. For example, the reflective layer may be configured by a single sheet.

It is sectional drawing of the solar cell module of one Example of this invention. It is the elements on larger scale of the solar cell module of FIG. It is an exploded view of the solar cell module of FIG. It is a schematic diagram which shows the path | route of the sunlight which injects from the surface member side. It is a block diagram of the photovoltaic cell of the solar cell module of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar cell 2 Connection member 3 EVA layer 3a, 3b EVA sheet | seat 4 Front surface member 5 Back surface member 7 Frame body 9 Reflective layer 10 Solar cell module 11 Crystalline silicon substrate 12, 16 i-type amorphous silicon layer 13 p-type Amorphous silicon layer 14 translucent conductive film 15, 19 collector electrode 17 n-type amorphous silicon layer 18 translucent conductive film

Claims (4)

In a solar cell module formed by arranging a plurality of double-sided light incident solar cells spaced apart from each other between a light-transmitting front surface member and a light-transmitting back surface member, and sealing with a filler,
A solar cell comprising a reflective layer that reflects light from a region opposite to the solar cell to a position facing the outer edge of the solar cell from a region not facing the solar cell. module. When the distance between the solar cell and the reflective layer is D, the refractive index of air is N0, and the refractive index of the filler and the surface member is N1, the portion of the reflective layer facing the outer edge of the solar cell The dimension L of
L = D × tan θ1 where θ1 = sin ⁻¹ (N0 / N1)
The solar cell module according to claim 1, wherein:   The solar cell module according to claim 1, wherein the reflective layer is provided on a surface on the solar cell side of the back surface member so as to correspond between the adjacent solar cells.   In the outer side of the outermost solar cell located on the outermost side, the reflective layer has a portion corresponding to the outer side of the solar cell provided on the surface of the back member opposite to the solar cell, 4. The solar cell module according to claim 1, wherein the portion facing the outer edge of the battery cell is provided on a surface of the back member on the solar cell side.

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