JPWO2013140553A1 - Solar cell module - Google Patents

Abstract

Provided is a solar cell having improved moisture resistance. The solar cell module 1 includes a solar cell 10, a first protection member 14, a second protection member 15, and a sealing material 13. The first protective member 14 is disposed on one side of the solar cell 10. The second protection member 15 is made of a resin sheet disposed on the other side of the solar cell 10. The sealing material 13 is disposed between the first protective member 14 and the second protective member 15. The sealing material 13 seals the solar cell 10. The solar cell 10 includes a photoelectric conversion unit 10 a and an electrode 21. The electrode 21 is disposed on the photoelectric conversion unit 10a. The electrode 21 includes a conductive material and a polyether-based urethane resin.

Description

  The present invention relates to a solar cell module.

  Patent Document 1 describes a solar cell having an electrode formed of a silver paste.

JP 2009-253096 A

There is a desire to improve the moisture resistance of solar cell modules.
The main object of the present invention is to provide a solar cell module having improved moisture resistance.

  The solar cell module according to the present invention includes a solar cell, a first protective member, a second protective member, and a sealing material. The first protective member is disposed on one side of the solar cell. A 2nd protection member consists of a resin sheet distribute | arranged to the other side of the solar cell. The sealing material is disposed between the first protective member and the second protective member. The sealing material seals the solar cell. A solar cell has a photoelectric conversion part and an electrode. The electrode is disposed on the photoelectric conversion unit. The electrode includes a conductive material and a polyether-based urethane resin.

  According to the present invention, a solar cell module having improved moisture resistance can be provided.

FIG. 1 is a schematic cross-sectional view of a solar cell module according to an embodiment of the present invention. FIG. 2 is a schematic plan view of a solar cell in one embodiment of the present invention. FIG. 3 is a schematic rear view of the solar cell in one embodiment of the present invention. FIG. 4 shows the ratio of the curve factor (FF) of the solar cell module according to the example to the curve factor (FF) of the solar cell module according to the comparative example (the curve of the solar cell module according to the example). It is a graph showing a factor (FF)) / (curve factor (FF) of the solar cell module which concerns on a comparative example)).

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described, and the ratio of the dimensions of the objects drawn in the drawings may be different from the ratio of the dimensions of the actual objects. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

  As shown in FIG. 1, the solar cell module 1 includes a plurality of solar cells 10 that are electrically connected by a wiring material 11. But the solar cell module may have only one solar cell.

  The solar cell 10 has a photoelectric conversion unit 10a. The photoelectric conversion unit 10a generates carriers such as electrons and holes when receiving light. The photoelectric conversion unit 10a may generate a carrier only when light is received on one main surface 10a1. The photoelectric conversion unit 10a may generate power not only when light is received on one main surface 10a1 but also when light is received on the other main surface 10a2. For example, the photoelectric conversion unit 10a may include a substrate made of a semiconductor material. Specifically, the photoelectric conversion unit 10a may include, for example, a crystalline silicon plate, and a p-type semiconductor layer and an n-type semiconductor layer disposed on the crystalline silicon plate. The photoelectric conversion unit 10a may be configured by a crystalline silicon plate having a p-type dopant diffusion region and an n-type dopant diffusion region exposed on the surface.

  First and second electrodes 21 and 22 are disposed on the photoelectric conversion unit 10a. Specifically, the first electrode 21 is disposed on the main surface 10a1. The second electrode 22 is disposed on the main surface 10a2. One of the first and second electrodes 21 and 22 is an electrode that collects majority carriers, and the other is an electrode that collects minority carriers.

  The first electrode 21 has a plurality of finger portions 21a and a bus bar portion 21b. The plurality of finger portions 21a are arranged at intervals from each other along the x-axis direction. The plurality of finger portions 21a are electrically connected to the bus bar portion 21b. The first electrode 21 is electrically connected to the wiring member 11 mainly in the bus bar portion 21b.

  The second electrode 22 has a plurality of finger portions 22a and a bus bar portion 22b. The plurality of finger portions 22a are spaced apart from each other along the x-axis direction. The plurality of finger portions 22a are electrically connected to the bus bar portion 22b. The second electrode 22 is electrically connected to the wiring member 11 mainly at the bus bar portion 22b.

  A transparent conductive oxide layer 31 is disposed between the first electrode 21 and the main surface 10a1. The transparent conductive oxide layer 31 is disposed so as to cover substantially the entire main surface 10a1. A transparent conductive oxide layer 32 is disposed between the second electrode 22 and the main surface 10a2. The transparent conductive oxide layer 32 is disposed so as to cover substantially the entire main surface 10a2. The transparent conductive oxide layers 31 and 32 can be made of indium tin oxide (ITO), for example.

  A first protective member 14 is disposed on one side of the solar cell 10. A second protection member 15 is disposed on the other side of the solar cell 10. A sealing material 13 is disposed between the first protection member 14 and the second protection member 15. The solar cell 10 is sealed by the sealing material 13. The 1st protection member 14 located in the light-receiving surface side of the solar cell 10 is comprised by the glass plate, the ceramic plate, or the resin plate. The 2nd protection member 15 located in the back surface side of the solar cell 10 consists of a resin sheet which does not contain barrier layers, such as a metal layer and an inorganic oxide layer. The sealing material 13 can be composed of, for example, a crosslinkable resin such as ethylene / vinyl acetate copolymer or a non-crosslinkable resin such as polyolefin.

  As the electrode binder resin, an ester urethane resin synthesized using an ester polyol is generally used. This is because the mechanical strength and heat resistance of the electrode can be improved by using an ester urethane resin.

  The ester urethane resin is hydrolyzed. However, when an ester-based urethane resin is used as an electrode material for solar cells, it has not been recognized as a problem that the ester-based urethane resin has a property of being hydrolyzed. This is because the solar cell is sealed with a sealing material, so that almost no moisture is mixed into the electrode. Moreover, even if water is slightly mixed into the electrode and the ester urethane resin is hydrolyzed, the electrical resistance of the electrode itself does not increase. Therefore, it was thought that the photoelectric conversion efficiency of a solar cell did not fall with hydrolysis of ester type urethane resin.

  However, as a result of intensive studies, the present inventors have found that when the ester urethane resin is hydrolyzed, the electrical resistance at the interface between the electrode and the photoelectric conversion part or the transparent conductive oxide layer increases. In particular, when a transparent conductive oxide layer is provided between the electrode and the photoelectric conversion unit, the interface resistance between the electrode and the transparent conductive oxide layer is an ester-based urethane. It has been found that it tends to increase with the hydrolysis of the resin. One possible reason is that the adhesion between the electrode and the photoelectric conversion part or the transparent conductive oxide layer is reduced by hydrolysis of the ester-based urethane resin.

  In the solar cell module 1, the electrodes 21 and 22 contain a polyether-based urethane resin. The polyether-based urethane resin is a resin including a polyether-based polyol unit. Polyether urethane resins are less susceptible to hydrolysis than ester urethane resins. Therefore, the adhesiveness between the electrodes 21 and 22 including the polyether-based urethane resin and the transparent conductive oxide layers 31 and 32 is not easily lowered. For this reason, the interface resistance between the electrodes 21 and 22 and the transparent conductive oxide layers 31 and 32 is difficult to increase. Therefore, the solar cell module 1 has improved moisture resistance.

  In the solar cell module 1, the second protective member 15 is made of a resin sheet that does not include a barrier layer such as a metal layer or an inorganic oxide layer. For this reason, the second protective member 15 has a high moisture permeability. Therefore, moisture easily enters the sealing material 13. Therefore, the electrodes 21 and 22 are likely to come into contact with moisture. Therefore, it is effective that the electrodes 21 and 22 include a polyether-based urethane resin that is difficult to hydrolyze.

  Actually, a solar cell module using a polyether-based urethane resin as an electrode binder (Example) and a solar cell module using an ester-based urethane resin as an electrode binder (Comparative Example) were prepared. The solar cell modules produced in each of the examples and comparative examples were left in an atmosphere of 85% humidity and 85 ° C., and the fill factor (FF) at each standing time was measured. FIG. 4 shows a ratio of the curve factor (FF) of the solar cell module according to the example to the curve factor (FF) of the solar cell module according to the comparative example at each time.

  From the results shown in FIG. 4, it can be seen that the moisture resistance of the solar cell module can be improved by including the polyether urethane resin in the electrode.

  The polyether-based urethane resin preferably includes a urethane resin formed by an addition reaction between a compound having an isocyanate group and a polyether polyol.

  Specific examples of the compound having an isocyanate group preferably used include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, tolidine diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, and hexamethylene diisocyanate. And aliphatic polyisocyanates such as isophorone diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, octamethylene diisocyanate, and trimethylhexamethylene diisocyanate, and mixtures thereof. Among these polyisocyanate compounds, when the component contains polymethylene polyphenyl polyisocyanate having three or more nuclei, the resistance becomes lower. Moreover, the terminal isocyanate group containing compound synthesize | combined by making polyisocyanate and a polyol react can also be used as a compound which has an isocyanate group. The polyol in this case is not particularly limited, and general polyether polyols, polyester polyols, polycarbonate polyols and the like can be used. The blocking agent for the compound having an isocyanate group is not particularly limited, and imidazoles, phenols, oximes and the like can be used.

  Specific examples of the polyether polyol preferably used include polypropylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, and mixtures thereof.

(Modification)
The electrode may be arranged immediately above the photoelectric conversion unit. That is, the transparent conductive oxide layer may not be disposed between the electrode and the photoelectric conversion unit.

  The electrode may be provided in a planar shape on the back side of the solar cell so as to cover substantially the entire surface of the photoelectric conversion unit. The solar cell may be a back junction solar cell. In these cases, many electrode materials are used on the back side of the solar cell. The second protective member 15 described above is disposed on the back side of the solar cell. Therefore, when the electrode on the back surface side of the solar cell is a resin containing a polyether-based urethane resin, hydrolysis of the electrode on the back surface side of the solar cell due to moisture mixed from the second protective member 15 side is suppressed. The

DESCRIPTION OF SYMBOLS 1 ... Solar cell module 10 ... Solar cell 10a ... Photoelectric conversion part 13 ... Sealing material 14 ... 1st protection member 15 ... 2nd protection member 21 ... 1st electrode 22 ... 2nd electrode 31, 32 ... Transparent Conductive oxide layer

Claims (5)

Solar cells,
A first protective member disposed on one side of the solar cell;
A second protective member made of a resin sheet disposed on the other side of the solar cell;
A sealing material disposed between the first protective member and the second protective member, and sealing the solar cell;
With
The solar cell is
A photoelectric conversion unit;
An electrode that is disposed on the photoelectric conversion portion and includes a conductive material and a polyether-based urethane resin;
A solar cell module. The solar cell module according to claim 2, wherein
The solar cell module in which the said polyether-type urethane resin contains the urethane resin formed by the addition reaction of the compound which has an isocyanate group, and a polyether polyol. The solar cell module according to claim 1 or 2,
The solar cell module further provided with the transparent conductive oxide layer distribute | arranged between the said photoelectric conversion part and the said electrode. It is a solar cell module as described in any one of Claims 1-3,
The said electrode is a solar cell module provided in planar shape so that the other side of the said solar cell may cover the substantially whole surface of a photoelectric conversion part. It is a solar cell module as described in any one of Claims 1-4, Comprising:
The solar cell is a solar cell module of a back junction type.

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