JP2010092908A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively suppress an increase in temperature of a solar battery cell without complicating the configuration of the solar battery module. <P>SOLUTION: In the solar battery module, at least some of electrodes of the solar battery cell are formed of an alloy material which becomes a solid-liquid coexistence state within a predetermined temperature range. In this case, the temperature range causing the solid-liquid coexistence state of the alloy material may partially overlap on a temperature range causing the operation of the solar battery cell. Thus, when the temperature of the solar battery cell rises in usage state, at least some of the electrodes become the solid-liquid coexistence state and the heat of the solar battery cell is absorbed as latent heat. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solar cell module.

Patent Document 1 discloses a solar cell module. This solar cell module includes a plurality of solar cells and lead wires that electrically connect the electrodes of the plurality of solar cells. The plurality of solar cells and lead wires that electrically connect them are enclosed in a resin material layer.
It is known that the power generation capacity of solar cells decreases as the temperature rises. Therefore, in the solar battery module, it is necessary to suppress the temperature rise of the solar battery cell and prevent the power generation capacity from being lowered.
Regarding the above points, in the solar cell module described in Patent Document 1, a heat collecting tube through which a heat medium flows is provided to cool and recover the solar cells. A solar cell module that performs heat recovery together with this solar cell module is generally called a hybrid solar cell module.
JP-A-11-243441

In the hybrid solar cell module, the heat recovery by the heat collecting tube is performed, so that the temperature rise of the solar cell can be surely prevented. However, since a heat collecting tube and a heat exchanger are required, the configuration of the solar cell module becomes relatively complicated. There is a need for a technique that can effectively suppress the temperature rise of a solar battery cell without requiring such a configuration.
The present invention solves the above problems. That is, this invention provides the technique which can suppress effectively the temperature rise of a photovoltaic cell, without making the structure of a photovoltaic module complicated.

The present invention is embodied in a solar cell module having at least one solar cell. In this solar battery module, at least a part of the electrodes of the solar battery cell is formed of an alloy material that is in a solid-liquid coexistence state in a predetermined temperature range. And the temperature range which becomes the solid-liquid coexistence state of the alloy material overlaps with the temperature range which can operate | move a solar cell at least partially, It is characterized by the above-mentioned.
In this solar cell module, when the temperature of the solar cell rises in use, at least a part of the electrode is in a solid-liquid coexistence state, and the heat of the solar cell is absorbed as latent heat. Thereby, the temperature rise in the use condition of a photovoltaic cell is prevented effectively. At this time, the electrode of the solar battery cell is not completely melted and remains in a solid-liquid coexistence state in which a solid portion is present, so that its shape is not lost.
According to this solar cell module, the temperature rise of the solar cells is suppressed, and the power generation capacity is prevented from being lowered. It is only necessary to change the configuration of the electrode of the solar battery cell, and no heat collecting tube or heat exchanger is required, so that the configuration of the solar battery module can be made relatively simple.

It is preferable that the above-described solar cell module further includes a lead wire that is electrically connected to the electrode of the solar cell. In this case, it is preferable that the electrode and the lead wire of the solar battery cell are joined to each other via the above-described alloy material.
According to this configuration, the above-described alloy material has not only a function of cooling the solar battery cell but also a function of joining the electrode of the solar battery cell and the lead wire. There is no need to separately provide a bonding material for bonding the electrode of the solar battery cell and the lead wire.

The above-described solar cell module preferably further includes a resin material layer in which solar cells and lead wires are enclosed. In this case, the temperature range in which the alloy material is in a solid-liquid coexistence state preferably overlaps at least partially with the temperature range in which the resin material constituting the resin material layer can be thermocompression bonded.
As will be described in detail later, the resin material layer of the solar cell module can be formed by thermocompression bonding. In this case, if the heating temperature when forming the resin material layer is a temperature at which the alloy material is in a solid-liquid coexistence state, the alloy material is in a solid-liquid coexistence state when the resin material layer is formed by thermocompression bonding. be able to. At this time, if the lead wire is adjacent to the alloy material, the resin material layer is formed by thermocompression bonding, and at the same time, the electrode of the solar battery cell and the lead wire can be joined to each other. Therefore, it is not necessary to previously join the electrode of the solar battery cell and the lead wire, and the manufacturing process of the solar battery module can be simplified.

As is clear from the above, the present invention is also embodied in a novel and useful method for manufacturing a solar cell module. This manufacturing method is a method for manufacturing a solar battery module having at least one solar battery cell, wherein a lead wire is disposed adjacent to an electrode of the solar battery cell, and the solar battery and the lead wire are disposed between a pair of resin material sheets. And a laminating step of thermocompression bonding a pair of resin material sheets with the solar cell and the lead wires interposed therebetween. In this manufacturing method, at least a part of the electrodes of the solar battery cell is formed of an alloy material that is in a solid-liquid coexistence state in a predetermined temperature range. At least partially overlaps the operable temperature range of the battery cell. Moreover, the temperature range in which the alloy material is in a solid-liquid coexistence state is also a range including the heating temperature (attainment temperature) in the laminating process. Thereby, in the above-described laminating step, the electrode of the solar battery cell and the lead wire are bonded to each other by the alloy material in a solid-liquid coexistence state.
According to this manufacturing method, the solar cell module according to the present invention described above can be efficiently manufactured.

  ADVANTAGE OF THE INVENTION According to this invention, although it is a comparatively simple structure, the solar cell module in which the temperature rise of a photovoltaic cell is prevented effectively is implement | achieved. According to the present invention, the power generation capability of the solar cell module is remarkably improved, and the effective use of solar energy can be promoted in more fields.

First, preferred embodiments for carrying out the present invention will be listed.
(Embodiment 1) The present invention can be applied to various types of solar cell modules, and is particularly limited by the types of solar cells (silicon-based, compound-based, organic-based, etc.) included in the solar cell modules. There is no. If the solar battery cell which a solar cell module has is a thing in which power generation capability falls with a temperature rise, this invention can be implemented effectively.
(Embodiment 2) When carrying out the present invention, an alloy containing tin (Sn) as a main component can be adopted as an alloy material that is in a solid-liquid coexistence state within a predetermined temperature range. In particular, Sn-48In (solidus temperature 117 ° C., liquidus temperature 131 ° C.), Sn-43Pb-14Bi (solidus temperature 135 ° C., liquidus temperature 208 ° C.), Sn-20Bi (solidus temperature) 144 ° C, liquidus temperature 208 ° C), Sn-40Bi (solidus temperature 139 ° C, liquidus temperature 174 ° C), Sn-50Bi (solidus temperature 139 ° C, liquidus temperature 154 ° C), etc. It can be suitably employed. In these alloys, at least a part of the temperature range in which the solid-liquid coexistence state is 150 ° C. or less (a temperature range in which a general solar cell can operate, and a temperature range that can be taken by the solar cell during normal use) ), And by changing the state (phase change) during use of the solar cell module, the heat of the solar cell can be absorbed as latent heat.
(Mode 3) As the resin material forming the resin material layer, a transparent resin material can be employed, for example, ethylene vinyl acetate (EVA) can be employed. Moreover, it is preferable to contain the filler which improves the intensity | strength in the resin material which forms a resin material layer.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows the configuration of a solar cell module 10 of this example.
The solar cell module 10 mainly includes a plurality of solar cells 20, a plurality of lead wires 18 that electrically connect the plurality of solar cells 20, a front cover 12 and a back cover 16 that face each other, and a front cover. 12 and the back cover 16 are provided with a resin material layer 14 filled therein.

  Each solar cell 20 is an element that converts light energy such as sunlight or artificial light into electric power, and generates electric power when irradiated with sunlight or artificial light. The plurality of solar cells 20 are connected in series by a plurality of lead wires 18. The plurality of solar cells 20 and the plurality of lead wires 18 are disposed between the front cover 12 and the back cover 16 and are enclosed in the resin material layer 14.

The front cover 12 is a protective sheet that protects the surface of the solar cell module 10. The front cover 12 is made of a transparent material. The front cover 12 can be formed of, for example, glass or a translucent resin film.
The back cover 16 is a protective sheet for protecting the back surface of the solar cell module 10 and securing the strength of the solar cell module 10. The back cover 16 can be formed of, for example, glass, metal, or PET (polyethylene terephthalate).

The resin material layer 14 seals the plurality of solar cells 20 and the plurality of lead wires 18 and joins the front cover 12 and the back cover 16 to each other. The resin material layer 14 is formed of a transparent resin material. The resin material layer 14 can be formed of, for example, ethylene vinyl acetate (EVA). Further, the resin material layer 14 contains a filler for improving the strength.
The front cover 12, the back cover 16, and the resin material layer 14 constitute a housing that accommodates the solar cells 20, and protects the solar cells 20 from impact, moisture, dust, and the like.

FIG. 2 schematically shows the configuration of one solar battery cell 20. The solar battery cell 20 is a silicon solar battery cell using a single crystal silicon substrate 26. As shown in FIG. 2, the solar battery cell 20 mainly includes a silicon substrate 26, a surface electrode 22 formed on the surface of the silicon substrate 26 (upper surface in FIG. 2), and a back surface of the silicon substrate 26 (in FIG. 2). A back electrode 28 formed on the lower surface is provided.
The silicon substrate 26 has a two-layer structure of a p-type layer 26a showing p-type conductivity and an n-type layer 26b showing n-type conductivity. The p-type layer 26 a is located on the back side of the silicon substrate 26, and the n-type layer 26 b is located on the front side of the silicon substrate 26. The two-layer structure of the silicon substrate 26 can be formed, for example, by preparing a p-type silicon substrate and introducing n-type impurities into the surface thereof. Alternatively, it can be formed by preparing a p-type silicon substrate and growing an n-type silicon layer on the surface thereof.

The surface electrode 22 is formed on a part of the surface of the silicon substrate 26. Thereby, sunlight (or artificial light) irradiated to the solar battery cell 20 can enter the silicon substrate 26 in a range where the surface electrode 22 is not formed. An antireflection film 24 is formed in a range where the surface electrode 22 is not formed on the surface of the silicon substrate 26.
The surface electrode 22 has a main electrode portion 22a and an alloy portion 22b. The main electrode portion 22a is formed of a single type of metal (for example, silver) and is in ohmic contact with the n-type layer 26b of the silicon substrate 26. The alloy part 22b is provided on the surface of the main electrode part 22a, and joins the main electrode part 22a and the lead wire 18 to each other. Here, the alloy portion 22b is an alloy material that is in a solid-liquid coexistence state in a predetermined temperature range, and at least a part of the temperature range in which the solid-liquid coexistence state exists is 150 ° C. or less. Yes. Here, the temperature range of 150 ° C. or less matches the operable temperature range (upper limit temperature) of the solar battery cell 20. That is, the temperature range in which the alloy part 22b is in the solid-liquid coexistence state is configured to at least partially overlap the temperature range in which the solar battery cell 20 can operate.

  The back electrode 28 is formed on substantially the entire back surface of the silicon substrate 26. Similarly, the back electrode 28 has a main electrode portion 28a and an alloy portion 28b. The main electrode portion 28a is formed of a single type of metal (for example, silver) and is in ohmic contact with the p-type layer 26a of the silicon substrate 26. The alloy portion 28b is provided on the surface of the main electrode portion 28a, and joins the main electrode portion 28a and the lead wire 18 to each other. Similarly to the surface electrode 22, the back surface electrode 28 also has an alloy portion 28b that is an alloy material that is in a solid-liquid coexistence state in a predetermined temperature range, and at least a part of the temperature range in which the solid-liquid coexistence state is 150. It is made of an alloy material having a temperature of ℃ or less. That is, also in the back electrode 28, the temperature range in which the alloy part 28b is in a solid-liquid coexistence state is configured to at least partially overlap the temperature range in which the solar battery cell 20 can operate.

  Here, as an alloy material that is in a solid-liquid coexistence state in a temperature range of 150 ° C. or lower, it is often found in an alloy material mainly composed of tin (Sn), for example, Sn-48In (solidus temperature 117 ° C., (Liquidus temperature 131 ° C), Sn-43Pb-14Bi (solidus temperature 135 ° C, liquidus temperature 208 ° C), Sn-20Bi (solidus temperature 144 ° C, liquidus temperature 208 ° C), Sn- Examples include 40 Bi (solidus temperature 139 ° C., liquidus temperature 174 ° C.) and Sn-50Bi (solidus temperature 139 ° C., liquidus temperature 154 ° C.). The alloy part 22b of the front electrode 22 and the alloy part 28b of the back electrode 28 may be formed using any of the above alloy materials. In this case, the alloy portions 22b and 28b of both the electrodes 22 and 28 can be formed of the same type of alloy material or different types of alloy materials. In the present embodiment, the alloy portions 22b and 28b of both electrodes 22 and 28 are formed of Sn-48In (solidus temperature 117 ° C., liquidus temperature 131 ° C.).

With the above configuration, in the solar cell module 10 of this embodiment, when sunlight (or artificial light) is irradiated, each solar cell 20 converts the light energy into electric energy, and the electric energy is lead. Output through line 18.
In the solar cell module 10, the solar cell 20 generates heat during the above-described power generation, and the temperature of the solar cell 20 rises due to light energy that is not converted into electric energy. As is well known, the power generation capacity of the solar battery cell 20 decreases as the temperature increases (particularly, the output voltage decreases). Moreover, if the temperature rise of the photovoltaic cell 20 progresses, the failure of the solar cell module 10 such as alteration and deformation of the resin material layer 14 occurs. Therefore, in the solar cell module 10, it is generally preferable that the temperature of the solar battery cell 20 is suppressed to 150 ° C. or less.
On the other hand, in the solar cell module 10 of the present embodiment, when the temperature of the solar battery cell 20 reaches the solidus temperature (117 ° C. in this case) of the alloy portions 22b and 28b, the state changes of the alloy portions 22b and 28b. Starts. That is, the alloy parts 22b and 28b change from the solid phase to the solid-liquid coexisting phase, and absorb the heat of the solar battery cell 20 as latent heat. Thereby, the temperature rise of the photovoltaic cell 20 is effectively prevented. At this time, the alloy portions 22b and 28b are not completely melted and remain in a solid-liquid coexistence state in which a solid portion exists, so that the shape thereof is not lost, and the lead wire 18 and There is no possibility that the joint will be disengaged.

Next, a method for manufacturing the solar cell module 10 will be described with reference to FIG.
First, as shown in FIG. 3, an arrangement step is performed in which each member constituting the solar cell module 10 is arranged between a pair of press dies 50. In this step, the first resin material sheet 14b, the plurality of solar cells 20 and the plurality of lead wires 18, the second resin material sheet 14a, and the front cover 12 are arranged in this order from the back cover 16. At this time, the electrodes 22 and 28 of the solar battery cell 20 and the lead wires 18 are arranged adjacent to each other so that the alloy portions 22b and 28b of the electrodes 22 and 28 and the lead wires 18 are in contact with each other.
Next, a heat pressing is performed by a pair of press dies 50, and a laminating process is performed in which the pair of resin material sheets 14a and 14b are thermocompression bonded. Thereby, a pair of resin material sheet 14a, 14b becomes united, and the resin material layer 14 is formed (refer FIG. 1). The front cover 12 and the back cover 16 are joined to each other by the resin material layer 14. The plurality of solar cells 20 and the plurality of lead wires 18 are enclosed in the resin material layer 14.

  Here, the heating temperature (setting temperature of the press die 50) in the laminating process is set to a temperature higher than the solidus temperature of the alloy parts 22b and 28b and lower than the liquidus temperature. . For example, when the alloy parts 22b and 28b are formed of Sn-48In (solidus temperature 117 ° C., liquidus temperature 131 ° C.), the heating temperature in the laminating process may be set to 120 ° C. to 130 ° C. When the heating temperature in the laminating process is higher than the solidus temperature of the alloy parts 22b and 28b, the alloy parts 22b and 28b change to a solid-liquid coexistence state during the laminating process. Thereby, the adjacent electrodes 22 and 28 and the lead wire 18 can be joined simultaneously. Further, if the heating temperature in the laminating process is lower than the liquidus temperature of the alloy parts 22b and 28b, the alloy parts 22b and 28b are not completely melted. Large changes can also be prevented.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the above-described embodiment, the alloy portions 22b and 28b are formed on a part of the electrodes 22 and 28, but the entire electrodes 22 and 28b may be formed of an alloy material. Further, the alloy parts 22b and 28b can be formed not only on the surfaces of the electrodes 22 and 28 but also inside the electrodes 22 and 28.
In the above-described embodiment, the alloy parts 22 b and 28 b are formed on a part of the electrodes 22 and 28, but a similar alloy part may be formed on at least a part of the lead wire 18. Even in this case, the lead wire 18 changes to a solid-liquid coexistence state due to the temperature rise of the solar battery cell 20, and the heat of the solar battery cell 20 can be absorbed by the lead wire 18 as latent heat. Thereby, the temperature rise of the photovoltaic cell 20 can be effectively prevented.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The figure which shows the structure of a solar cell module. The figure which shows the structure of a photovoltaic cell. The figure which shows the manufacturing process of a solar cell module.

Explanation of symbols

10: Solar cell module 12: Front cover 14: Resin material layer 16: Back cover 18: Lead wire 20: Solar cell 22: Surface electrode 22a: Main electrode portion 22b: Alloy portion 26: Silicon substrate 26a: P-type layer 26b : N-type layer 28: back electrode 28a: main electrode part 28b: alloy part 50: press mold

Claims (4)

A solar cell module having at least one solar cell,
At least a part of the electrodes of the solar battery cell is formed of an alloy material that is in a solid-liquid coexistence state in a predetermined temperature range,
The temperature range in which the alloy material is in a solid-liquid coexistence state at least partially overlaps the temperature range in which the solar cells can operate. A lead wire electrically connected to the electrode of the solar battery cell;
The solar cell module according to claim 1, wherein the solar cell electrode and the lead wire are joined to each other via the alloy material. A resin material layer in which the solar cell and the lead wire are encapsulated;
The temperature range in which the alloy material is in a solid-liquid coexistence state at least partially overlaps with a temperature range in which the resin material constituting the resin material layer can be thermocompression bonded. Solar cell module. A method for producing a solar cell module having at least one solar cell,
Arranging the lead wire adjacent to the electrode of the solar battery cell, and placing the solar cell and the lead wire between a pair of resin material sheets;
Comprising a laminating step of thermocompression bonding a pair of resin material sheets across the solar cell and the lead wire,
At least a part of the electrodes of the solar battery cell is formed of an alloy material that is in a solid-liquid coexistence state in a predetermined temperature range,
The temperature range in which the alloy material is in a solid-liquid coexistence state is a range that at least partially overlaps the operable temperature range of the solar battery cell and includes the heating temperature in the laminating step,
In the laminating step, the solar cell module manufacturing method is characterized in that the electrode of the solar battery cell and the lead wire are joined to each other by the alloy material in a solid-liquid coexistence state.

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