WO2017163554A1

WO2017163554A1 - Solar cell module

Info

Publication number: WO2017163554A1
Application number: PCT/JP2017/001316
Authority: WO
Inventors: 幸弘吉嶺
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2016-03-22
Filing date: 2017-01-17
Publication date: 2017-09-28
Also published as: JPWO2017163554A1

Abstract

A solar cell module 100 is provided with a first protection substrate 30, a first sealing layer 34, a plurality of solar cells 10, a second sealing layer 36, and a second protection substrate 32, which are laminated in this order. The thickness of the second protection substrate 32, said thickness being in the laminating direction, is larger than that of the first protection substrate 30. The melting point of the second sealing layer 36 is lower than that of the first sealing layer 34. The first protection substrate 30 may be disposed on the light receiving surface 12 side of the solar cells 10, and the second protection substrate 32 may be disposed on the rear surface 14 side of the solar cells 10. The first sealing layer 34 may be formed of a thermoplastic resin. The second sealing layer 36 may be formed of a thermosetting resin.

Description

Solar cell module

The present invention relates to a solar cell module.

The solar cell module has a plurality of solar cells. The plurality of solar cells are resin-sealed between the first protective member and the second protective member (see, for example, Patent Document 1).

International Publication No. 2012/128342

Depending on the external environment at the time of installation, a force may be applied in the direction in which the solar cell module is warped, which may lead to damage of the solar cell. Therefore, even when a force is applied in a direction in which warpage occurs, a module structure that can prevent damage to solar cells is preferable.

The present invention has been made in view of such circumstances, and an object thereof is to provide a solar cell module with improved reliability.

In order to solve the above problems, a solar cell module according to an aspect of the present invention includes a first protective substrate, a first sealing layer, a plurality of solar cells, and a second sealing layer, which are sequentially stacked. A second protective substrate. The second protective substrate has a larger thickness in the stacking direction than the first protective substrate, and the second sealing layer has a lower melting point than the first sealing layer.

Another embodiment of the present invention is also a solar cell module. The solar cell module includes a first protective substrate, a first sealing layer, a plurality of solar cells, a second sealing layer, and a second protective substrate that are sequentially stacked. The first protective substrate is disposed on the light receiving surface side of the plurality of solar cells. The second protective substrate is disposed on the back side of the plurality of solar cells, and has a greater thickness in the stacking direction than the first protective substrate.

According to the present invention, a solar cell module with improved reliability can be provided.

It is sectional drawing which shows the structure of the solar cell module which concerns on embodiment. It is a figure which shows typically the manufacturing process of a solar cell module. It is a figure which shows typically the effect which the solar cell module which concerns on embodiment shows.

An outline will be given before concretely explaining the present invention. The embodiment of the present invention is a solar cell module. The solar battery module has a plurality of solar battery cells, and adjacent solar battery cells are connected by a connecting member called a tab wiring. The solar cells connected by tab wiring are sandwiched between the first protective substrate and the second protective substrate and sealed with resin. In this embodiment, the strength of the module is increased by providing a difference between the thicknesses of the first protective substrate and the second protective substrate. When a glass plate is used as the protective substrate, the strength of the glass is generally proportional to the square of the thickness. Rather than having the same thickness, the difference in thickness between the two increases the overall strength of the module. In addition, by using a resin material having a lower melting point than the first protective substrate side as the sealing resin on the second protective substrate side, the second protective substrate side is less likely to be heated in the sealing process because the second protective substrate is thick. The solar battery cell can be more reliably sealed by suitably softening the resin. Thereby, a highly reliable solar cell module can be provided.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

FIG. 1 is a cross-sectional view showing the structure of a solar cell module 100 according to an embodiment. The solar cell module 100 includes a plurality of solar cells 10, a tab wiring 20 that connects adjacent solar cells 10, a first protective substrate 30, a second protective substrate 32, and a first sealing layer 34. And a second sealing layer 36.

The solar battery cell 10 is a layer that absorbs incident light and generates photovoltaic power, and includes a substrate made of a semiconductor material such as crystalline silicon, gallium arsenide (GaAs), or indium phosphorus (InP). The structure of the solar battery cell 10 is not particularly limited. In this embodiment, the solar battery cell 10 has a heterojunction of an n-type single crystal silicon substrate and amorphous silicon. For example, the solar cell 10 includes an i-type amorphous silicon layer, a p-type amorphous silicon layer doped with boron (B) or the like on a light-receiving surface side of an n-type single crystal silicon substrate, indium oxide or the like. The transparent conductive layers made of a photoconductive oxide are stacked in this order. Further, an i-type amorphous silicon layer, an n-type amorphous silicon layer doped with phosphorus (P) or the like, and a transparent conductive layer are laminated on the back side of the substrate in this order.

The solar battery cell 10 has a light receiving surface 12 that is one of the cell surfaces and a back surface 14 that is one of the cell surfaces and faces away from the light receiving surface 12. Here, the light receiving surface 12 means a main surface on which solar light is mainly incident in the solar battery cell 10, and is a surface on which most of the light incident on the solar battery cell 10 is incident. A light receiving surface electrode is formed on the light receiving surface 12, and a back electrode is formed on the back surface 14.

The tab wiring 20 is an elongated metal foil, for example, a copper foil coated with silver, tin, solder or the like, or an aluminum foil. The tab wiring 20 electrically and mechanically connects adjacent solar cells 10. One end of the tab wiring 20 is in electrical contact with the light receiving surface electrode formed on one light receiving surface 12 of the adjacent solar battery cell 10. The other end of the tab wiring 20 is brought into electrical contact with a back electrode formed on the other back surface 14 of the adjacent solar battery cell 10. The tab wiring 20 is bent in an inter-cell region between adjacent solar cells 10 so that the light receiving surface 12 and the back surface 14 of the adjacent solar cells 10 are arranged in the same plane. .

The first protective substrate 30 and the second protective substrate 32 are exterior members that protect the plurality of solar cells 10 from the external environment, and are, for example, glass substrates. The first protective substrate 30 is provided on the light receiving surface 12 side and transmits light in a wavelength band that the solar battery cell 10 absorbs for power generation. The second protective substrate 32 is provided on the back surface 14 side. The second protective substrate 32 is preferably thicker in the stacking direction than the first protective substrate 30 and has a thickness of 1.1 times or more that of the first protective substrate 30. By the thickness of the first protective substrate 30 t ₁ and providing a difference in thickness t ₂ of the second protective substrate 32, as the entire module when both of the thickness of the sum of (t 1 _{+ t} ₂₎ to a constant The strength of can be increased. Since the strength of the glass is generally proportional to the square of the thickness, if the total thickness is constant, the sum of the strengths of the two glasses is minimum when both thicknesses are equal (t ₁ = t ₂ ). It is to become.

The first sealing layer 34 and the second sealing layer 36 are sealing resin layers that prevent moisture from entering the solar cells 10 and improve the strength of the entire solar cell module 100. The 1st sealing layer 34 is provided between the photovoltaic cell 10 and the 1st protective substrate 30, ie, the light-receiving surface 12 side. The second sealing layer 36 is provided between the solar battery cell 10 and the second protective substrate 32, that is, on the back surface 14 side. The first sealing layer 34 is a thermoplastic resin, for example, a polyethylene-based or polypropylene-based resin. The second sealing layer 36 is a thermosetting resin, for example, an ethylene-vinyl acetate copolymer (EVA), a polyethylene-based or polypropylene-based resin containing a polyimide or a cross-linking material.

In the present embodiment, a resin having a melting point lower than that of the first sealing layer 34 is selected for the second sealing layer 36. That is, the resin material of the first sealing layer 34 has a relatively high melting point, and the resin material of the second sealing layer 36 has a relatively low melting point. The melting point of the resin material is, for example, at least when the average molecular weight of the polymer constituting the resin is large, when the ratio of the branched structure (weight to density) is high, and when the localized site is present in the main chain of the polymer In either case, the melting point increases. Therefore, by using resins having at least one of these different resin characteristics, the melting points of the first sealing layer 34 and the second sealing layer 36 can be made different. In addition, you may give the difference in melting | fusing point of a resin material using the characteristic different from the above-mentioned resin characteristic.

FIG. 2 is a diagram schematically showing a manufacturing process of the solar cell module 100. In this figure, the direction of the photovoltaic cell 10 is reversed upside down from FIG. A plurality of solar cells 10 are connected by tab wiring 20 to form a cell string 18. Next, the first sealing material 54 and the first protective substrate 30 are disposed on the light receiving surface 12 side of the cell string 18, and the second sealing material 56 and the second protective substrate 32 are disposed on the back surface 14 side. Subsequently, the first jig 40 and the first jig 40 are vertically moved so as to sandwich the laminate composed of the first protective substrate 30, the first sealing material 54, the cell string 18, the second sealing material 56, and the second protective substrate 32. The 2nd jig | tool 42 is arrange | positioned and it heats, applying a pressure to a laminated body. At this time, the first jig 40 is on the heating side, and the second jig 42 is on the pressing side. By the thermocompression bonding, the first sealing material 54 and the second sealing material 56 are fused to form the first sealing layer 34 and the second sealing layer 36, and the solar cell module 100 of FIG. 1 is completed. The configuration of the laminating apparatus is not particularly limited. In a modification, the first jig 40 may be the pressing side, the second jig 42 may be the heating side, and the first jig 40 and the second jig 42 may be used. Both may be on the heating side, and both the first jig 40 and the second jig 42 may be on the pressing side. Alternatively, the thermosetting second sealing layer 36 may be completely cured by placing the solar cell module 100 in a resin curing furnace after thermocompression bonding.

In the above-described thermocompression bonding step, the first jig 40 is disposed so as to be in contact with the first protective substrate 30, and the second jig 42 is disposed so as to be in contact with the second protective substrate 32. The first jig 40 has a heating device 44 such as a heater. The heating device 44 heats the first protective substrate 30. The heat generated by the heating device 44 is transmitted in the order of the first protective substrate 30, the first sealing material 54, the cell string 18, the second sealing material 56, and the second protective substrate 32. In the present embodiment, the first sealing material 54 and the second sealing material 56 are heated by heating from the first protective substrate 30 having a small thickness, compared with the case of heating from the second protective substrate 32 having a large thickness. Heat can be transmitted easily. Further, by using a resin material having a low melting point for the second sealing material 56 that is harder to be heated than the first sealing material 54, the first sealing material 54 and the second sealing material 56 are almost at the same timing. It can be softened and fused. Thereby, the thermocompression bonding process can be completed in a shorter time, and an increase in manufacturing cost can be suppressed.

Next, the effect produced by the solar cell module 100 will be described.
FIG. 3 is a diagram schematically illustrating an effect exhibited by the solar cell module 100 according to the embodiment. The solar cell module 100 is installed such that the first protective substrate 30 is vertically upward and the second protective substrate 32 is vertically downward. The solar cell module 100 may be installed so that the first protective substrate 30 is orthogonal to the vertical direction, or may be installed obliquely so that the first protective substrate 30 intersects the vertical direction. When the solar cell module 100 is installed in a place with snowfall with the first protective substrate 30 vertically upward, snow is deposited on the first protective substrate 30 and the positive polarity as indicated by the arrow A from above the first protective substrate 30 is obtained. A load is applied.

When a positive load is applied, bending occurs such that the center of the solar cell module 100 is directed downward. The first protective substrate 30 is subjected to compressive stress as indicated by arrow B, and the second protective substrate 32 is subjected to tensile stress as indicated by arrow C. In the solar cell module 100, since the first protective substrate 30 is thin and the second protective substrate 32 is thick, the neutral plane F of stress is close to the second protective substrate 32. Here, the neutral plane F refers to a place where no compressive stress or tensile stress is applied when the solar cell module 100 is bent. The range closer to the first protective substrate 30 than the neutral plane F is the compression region D to which compressive stress is applied, and the range closer to the second protective substrate 32 than the neutral plane F is the tensile region E to which tensile stress is applied. is there. As shown in the drawing, the neutral plane F of the stress is located closer to the second protective substrate 32 than the solar battery cell 10, so that the solar battery cell 10 included in the compression region D is subjected to compressive stress. Become. The crystalline semiconductor material constituting the solar battery cell 10 has a characteristic that it is weak against tensile stress but strong against compressive stress. According to the present embodiment, by increasing the thickness of the second protective substrate 32, it is possible to prevent a tensile stress from being generated in the solar battery cell 10 even when a positive load is applied to the solar battery module 100. Thereby, damage of the photovoltaic cell 10 can be prevented and the reliability of the solar cell module 100 can be improved.

According to this embodiment, since the first protective substrate 30 having a small thickness is provided on the light receiving surface 12 side of the solar battery cell 10, the attenuation amount of incident light caused by the first protective substrate 30 can be reduced. This is because even if the glass substrate is transparent to the incident light, the transmittance of the incident light can be reduced as the glass substrate becomes thicker. Therefore, according to this Embodiment, more light can be entered into the photovoltaic cell 10, and the power generation efficiency of the photovoltaic module 100 can be improved.

If the thickness of the first protective substrate 30 is reduced, the first protective substrate 30 may be easily warped depending on the external environment at the time of installation. For example, in summer when the intensity of sunlight is high, the solar battery cell 10 absorbs high-intensity incident light and becomes high temperature, and the temperature of the first protective substrate 30 also increases. Since the first protective substrate 30 has a small heat capacity, the first protective substrate 30 is likely to have a higher temperature than the second protective substrate 32. As a result, the first protective substrate 30 has a larger amount of thermal expansion than the second protective substrate 32, and the solar cell panel 60 warps so that the outer surface (light receiving surface) of the first protective substrate 30 is convex. It will be. If it does so, tensile stress may be added to the photovoltaic cell 10 and it may lead to damage of the photovoltaic cell 10.

On the other hand, in the present embodiment, a thermoplastic resin is used as the first sealing layer 34 between the first protective substrate 30 and the solar battery cell 10. Therefore, even when the first protective substrate 30 is warped due to the temperature rise of the solar cell module 100, the stress caused by the warp of the first protective substrate 30 due to the softening of the thermoplastic first sealing layer 34. Can be relaxed by the first sealing layer 34. Thereby, it is possible to prevent a strong tensile stress from being generated in the solar battery cell 10 and prevent the solar battery cell 10 from being damaged.

According to the present embodiment, the first sealing layer 34 on the light receiving surface 12 side is made of a thermoplastic resin, while the second sealing layer 36 on the back surface 14 side is made of a thermosetting resin, so that the solar cell module. 100 reliability can be improved. If both the first sealing layer 34 and the second sealing layer 36 are made of a thermoplastic resin, the entire sealing layer softens when the solar cell module 100 reaches a high temperature and shifts to the arrangement of the cell strings 18. May occur, leading to damage to the solar battery cell 10. According to the present embodiment, at least one of the sealing layers is made of a thermosetting resin, thereby preventing displacement of the cell string 18 at a high temperature and damaging the solar battery cell 10 due to the displacement of the cell string 18. Can be prevented.

One aspect of this embodiment is a solar cell module (100).
The solar cell module (100)
A first protective substrate (30), a first sealing layer (34), a plurality of solar cells (10), a second sealing layer (36), and a second protective substrate (32), which are sequentially stacked. And
The second protective substrate (32) has a greater thickness in the stacking direction than the first protective substrate (30),
The second sealing layer (36) has a lower melting point than the first sealing layer (34).

The first protective substrate (30) is disposed on the light receiving surface (12) side of the plurality of solar cells (10), and the second protective substrate (32) is the back surface (14) of the plurality of solar cells (10). It may be arranged on the side.

The first sealing layer (34) may be a thermoplastic resin, and the second sealing layer (36) may be a thermosetting resin.

The first protective substrate (30) may be installed on the upper side in the vertical direction.

Another aspect of the present embodiment is a solar cell module (100).
The solar cell module (100)
A first protective substrate (30), a first sealing layer (34), a plurality of solar cells (10), a second sealing layer (36), and a second protective substrate (32), which are sequentially stacked. And
The first protective substrate (30) is disposed on the light receiving surface side of the plurality of solar cells (10),
A 2nd protective substrate (32) is arrange | positioned at the back surface side of a several photovoltaic cell (10), and the thickness of a lamination direction is larger than a 1st protective substrate (30).

As described above, the present invention has been described with reference to the above-described embodiment. However, the present invention is not limited to the above-described embodiment, and the present invention can be appropriately combined or replaced with the configuration of the embodiment. It is included in the present invention.

DESCRIPTION OF SYMBOLS 10 ... Solar cell, 12 ... Light-receiving surface, 14 ... Back surface, 30 ... 1st protective substrate, 32 ... 2nd protective substrate, 34 ... 1st sealing layer, 36 ... 2nd sealing layer, 100 ... Solar cell module .

Claims

A first protective substrate, a first sealing layer, a plurality of solar cells, a second sealing layer, and a second protective substrate, which are sequentially stacked;
The second protective substrate has a larger thickness in the stacking direction than the first protective substrate,
The solar cell module, wherein the second sealing layer has a melting point lower than that of the first sealing layer.
The first protective substrate is disposed on a light receiving surface side of the plurality of solar cells,
The solar cell module according to claim 1, wherein the second protective substrate is disposed on a back surface side of the plurality of solar cells.
The solar cell module according to claim 1 or 2, wherein the first sealing layer is a thermoplastic resin, and the second sealing layer is a thermosetting resin.
The solar cell module according to any one of claims 1 to 3, wherein the first protective substrate is installed so as to be on an upper side in a vertical direction.
A first protective substrate, a first sealing layer, a plurality of solar cells, a second sealing layer, and a second protective substrate, which are sequentially stacked;
The first protective substrate is disposed on a light receiving surface side of the plurality of solar cells,
The solar cell module, wherein the second protective substrate is disposed on a back surface side of the plurality of solar cells and has a larger thickness in the stacking direction than the first protective substrate.