JP2018050026A - Solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell module of a double-sided glass protective substrate type superior in durability and barrier property, in which the superiority to conventional solar cell modules in quality stability is achieved by adequately suppressing cell cracking and the remanence of bubbles attributed to a material of a sealant on condition that an adequate heat resistance is held.SOLUTION: A solar cell module 10 of a double-sided glass protective substrate comprises a light receiving-side glass protective substrate 1, a light receiving-side sealant 2, a solar cell element 6, a non-light receiving-side transparent sealant 3, and a non-light receiving-side glass protective substrate 5 which are laminated in turn. The light receiving-side sealant 2 and the non-light receiving-side transparent sealant 3 are each a multilayer sealant comprising a polyethylene-based resin of 0.870-0.930 g/cmas a base resin, and having a gel fraction of 0%, and having a plurality of layers including a core layer, and a skin layer lower than the core layer in density and disposed on each outermost surface of the sealant.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solar cell module. More specifically, the present invention relates to a double-sided glass protective substrate type solar cell module.

  In recent years, solar cells as a clean energy source have attracted attention due to the growing awareness of environmental issues. Currently, various types of solar cell modules have been developed. Generally, a solar cell module has a configuration in which a transparent front protective substrate, a solar cell element, and a resin back protective substrate are laminated via a sealing material.

  There are various layers of solar cell modules, and the above-mentioned front protective substrate and the above-mentioned protective layer are particularly excellent in terms of barrier properties to prevent moisture from entering the module and long-term durability under severe use conditions. A solar cell module has been devised in which a back surface protection substrate is a glass protection substrate made of a glass protection substrate (see Patent Documents 1 and 2). In this specification, a solar cell module having a configuration in which the protective substrates disposed on both outermost surfaces of the module main body are glass substrates is referred to as a “double-sided glass protective substrate type solar cell module”.

  Here, the solar cell module is obtained by integrating the solar electronic element and the module constituent member including the sealing material and the like by a laminating process involving heating and pressing, regardless of the configuration. Manufactured. At the time of heat and pressure treatment for integration as a module, if the fluidity of the sealing material is insufficient, the follow-up to unevenness such as solar cell elements and lead wires and the embedding property (molding property) are lacking. The risk of damage to the solar cell element (cell cracking) increases. On the other hand, if a resin with high fluidity is used as the material resin for the sealing material, the heat resistance at the stage where the solar cell module is completed is likely to be insufficient. .

  Therefore, in order to ensure sufficient heat resistance of the sealing material at the stage of being integrated as a solar cell module while using a highly fluid resin as the material resin for the sealing material, It is widely performed to crosslink the sealing material at the time of laminating for integration as a module.

  However, when a large amount of a crosslinking agent such as an organic peroxide is added to the material resin of the sealing material in order to sufficiently advance the crosslinking, the gas derived from this crosslinking agent remains unnecessarily as bubbles in the module laminate. The problem that will occur. The problem of remaining bubbles in the module due to the material of the sealing material is that high pressure and tension are easily applied to the sealing material during the laminating process, and there is very little escape space for gas generated due to the structure. This is particularly apparent in the production of a substrate type solar cell module.

  Thus, in the double-sided glass protective substrate type solar cell module, there has been a demand for an improvement means that can sufficiently suppress “cell cracking” and “bubble remaining” in the laminate without impairing heat resistance. .

JP 11-31834 A JP 2013-98306 A

  The present invention has been made in view of the above situation, and in a double-sided glass protective substrate type solar cell module excellent in durability and barrier properties, while maintaining sufficient heat resistance, cell cracking and sealing It is an object of the present invention to provide a double-sided glass protective substrate type solar cell module that is superior in stability of quality compared to conventional products by sufficiently suppressing the remaining of bubbles derived from the material.

  As a result of intensive studies, the inventors of the present invention have encapsulated a double-sided glass protective substrate type solar cell module having a gel fraction of 0% (that is, non-crosslinked) and having a predetermined multilayer structure. By using the material, it was found that the above problems can be solved by avoiding the generation of degas derived from the resin material while maintaining the heat resistance and proper fluidity at the time of modularization, and the present invention has been completed. It was. More specifically, the present invention provides the following.

(1) A double-sided glass protective substrate type in which a light-receiving surface side glass protective substrate, a light-receiving surface side sealing material, a solar cell element, a non-light-receiving surface side transparent sealing material, and a non-light-receiving surface side glass protective substrate are sequentially laminated. a solar cell module, wherein the light-receiving surface side sealing member and the non-light receiving side transparent encapsulant as either 0.870 g / cm ³ or more 0.930 g / cm ³ or less polyethylene resin as a base resin of And having a gel fraction of 0% and comprising a plurality of layers including a core layer and a skin layer having a density equal to or lower than the density of the core layer and disposed on the outermost surface of the encapsulant. A solar cell module which is a multilayer sealing material.

  (2) In the non-light-receiving surface side transparent sealing material, the core layer has a thickness of 100 μm or more and 600 μm or less, the melting point of the core layer is 90 ° C. or more and 135 ° C. or less, and the thickness of each layer of the skin layer The solar cell module according to (1), each having a thickness of 30 μm to 200 μm and a melting point of the skin layer of 55 ° C. to 100 ° C.

(3) the light-receiving side encapsulant comprises a density 0.870 g / cm ³ or more 0.900 g / cm ³ or less of the polyethylene resin as a base resin, a gel fraction of 0% of the weak crosslinking sealant The solar cell module according to (1) or (2).

  (4) The silane copolymer formed by copolymerizing α-olefin and an ethylenically unsaturated silane compound as a comonomer is contained in the light-receiving surface side sealing material and the non-light-receiving surface side transparent sealing material. The solar cell module according to any one of (1) to (3).

  (5) A non-light-receiving surface side white sealing material is further laminated between the non-light-receiving surface side transparent sealing material and the non-light-receiving surface side glass protective substrate, and the non-light-receiving surface side white sealing The material is a multi-layer sealing material composed of a plurality of layers including a white core layer and a skin layer disposed on at least one of the outermost surfaces, and a white coloring material is formed only on the white core layer Is contained, The solar cell module in any one of (1) to (4).

  (6) The non-light-receiving surface side white sealing material has a core layer thickness of 100 μm or more and 600 μm or less, a melting point of the core layer of 90 ° C. or more and 120 ° C. or less, and a skin layer thickness of 30 μm or more. The solar cell module according to (5), which is 200 μm or less and the skin layer has a melting point of 70 ° C. or higher and 100 ° C. or lower.

  According to the present invention, in a double-sided glass protective substrate type solar cell module excellent in durability and barrier properties, while maintaining sufficient heat resistance, wraparound of colored portions and air bubbles derived from the material of the sealing material at the time of lamination By sufficiently suppressing the remaining, it is possible to provide a double-sided glass protective substrate type solar cell module that is more excellent in quality stability than conventional products.

It is drawing which shows typically the laminated constitution of the solar cell module of a double-sided glass protective substrate type | mold of this invention. It is drawing which shows typically the layer structure of the light-receiving surface side sealing material which comprises the solar cell module of the double-sided glass protection substrate type | mold of this invention. It is drawing which shows typically the layer structure of the non-light-receiving surface side transparent sealing material which comprises the solar cell module of a double-sided glass protection substrate type | mold of this invention. It is drawing which shows typically the layer structure of the non-light-receiving surface side white sealing material which comprises the solar cell module of a double-sided glass protection substrate type | mold of this invention.

  Hereinafter, the solar cell module of the present invention and the sealing material used for the solar cell module will be sequentially described.

<Solar cell module>
FIG. 1: is sectional drawing which shows an example of the laminated constitution about the solar cell module 10 of the double-sided glass protection substrate type | mold of this invention. The solar cell module 10 includes a light receiving surface side glass protective substrate 1, a light receiving surface side sealing material 2, a non-light receiving surface side transparent sealing material 3, a non-light receiving surface side white sealing material 4, from the light receiving surface side of incident light. The non-light-receiving surface side glass protective substrate 5 is laminated in this order, and the solar cell element 6 is arranged in such a manner that it is sealed between the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3. Yes.

  In the solar cell module 10, a polyethylene resin-based sealing material having an excellent balance between heat resistance and fluidity is disposed on the light-receiving surface side and the non-light-receiving surface side of the solar cell element. On the non-light-receiving surface side, the non-light-receiving surface-side transparent sealing material 3 is arranged, and further, the non-light-receiving surface-side white sealing material 4 is connected to the non-light-receiving surface-side transparent sealing material 3 and the non-light-receiving surface side. It is preferable to be disposed between the glass protective substrate 5.

  In the solar cell module 10, when the non-light-receiving surface side white sealing material 4 is arranged as described above, out of the incident light from the light-receiving surface side, the light does not enter the solar cell element 6 and is on the non-light-receiving surface side. The sunlight that has reached is reflected at the interface between the non-light-receiving surface side transparent sealing material 3 and the non-light-receiving surface side white sealing material 4 and is again guided to the light-receiving surface side of the solar cell element 6. The power generation efficiency of the solar cell module 10 is improved. Details of each of these sealing materials will be described later.

  About the light-receiving surface side glass protective substrate 1 and the non-light-receiving surface side glass protective substrate 5, various glass plate materials conventionally used as a light-transmitting substrate material constituting the solar cell module can be used without particular limitation. it can. In addition, the solar cell module 10 of this invention may also contain members other than the said member.

  The solar cell element 6 is not particularly limited. Not only a crystalline silicon solar cell manufactured using a single crystal silicon substrate or a polycrystalline silicon substrate, but also a thin film solar cell (CIGS) using amorphous silicon, microcrystalline silicon, a chalcopyrite compound, or the like is preferably used. be able to.

[Method for manufacturing solar cell module]
The solar cell module 10 includes a light receiving surface side glass protective substrate 1, a light receiving surface side sealing material 2, a non-light receiving surface side transparent sealing material 3, a non-light receiving surface side white sealing material 4, and a non-light receiving surface side glass protective substrate 5. Then, the module constituent members including the solar cell element 6 and the like are sequentially laminated and then integrated by vacuum suction or the like, and then the above members are thermocompression-molded as an integrally formed body by a molding method such as a lamination method. Can be manufactured.

  And the sealing material composition used as a material of each sealing material which comprises the solar cell module 10 does not contain a crosslinking agent, or uses the sealing material composition in which a crosslinking agent does not remain substantially after film-forming. Therefore, after film formation, the crosslinking treatment in the manufacturing process of the solar cell module is unnecessary, and in this respect also, improvement in productivity can be expected as compared with the production of the solar cell module in which the conventional crosslinking treatment is essential.

<Encapsulant>
The light-receiving surface side sealing material 2, the non-light-receiving surface side transparent sealing material 3 and the non-light-receiving surface side white sealing material 4 constituting the solar cell module 10 all have a density of 0.870 g / cm ³ or more. A polyethylene resin of 930 g / cm ³ or less is a base resin, and each is formed of a non-crosslinked resin film having a gel fraction of 0%.

  In this specification, “gel fraction (%)” means that 0.1 g of a sealing material is put into a resin mesh, extracted with toluene at 120 ° C. for 24 hours, taken out together with the resin mesh, weighed after drying, and before and after extraction. The mass ratio of the residual insoluble matter is measured and the gel fraction is obtained. The gel fraction of 0% means that the residual insoluble matter is substantially 0, and the crosslinking reaction of the sealing material composition has not substantially started. More specifically, “gel fraction 0%” means that the above-mentioned residual insoluble matter is not present at all, and that the above-mentioned residual insoluble matter mass% measured by a precision balance is less than 0.05% by mass. Shall be said. The residual insoluble matter does not include pigment components other than the resin component. When a mixture other than these resin components is mixed in the residual insoluble matter by the above test, for example, by separately measuring the content of these mixtures in the resin component beforehand, The gel fraction that should be originally obtained can be calculated for the residual insoluble matter derived from the resin component excluding the inclusions.

[Light-receiving surface side sealing material and non-light-receiving surface side transparent sealing material (transparent sealing material)]
The light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed into a film or sheet by molding a sealing material composition, which will be described in detail below, by a conventionally known method. It is. In addition, the sheet form in this invention means the film form, and there is no difference in both.

  The light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 may be single-layer films, but as shown in FIGS. 2 and 3, the core layer 21 (31) and both surfaces of the core layer It is a multilayer film comprised by the skin layer 22 (32) arrange | positioned in. The multilayer film in the present specification is a film or sheet having a structure having at least one outermost layer, preferably a skin layer formed on both outermost layers, and a core layer which is a layer other than the skin layer. Say that. When the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are multilayer films, the skin layer 22 that faces at least the light-receiving surface-side glass protective substrate 1 or the non-light-receiving surface-side glass protective substrate 5. (32) should just be a non-crosslinked resin layer which consists of a sealing material composition which demonstrates a detail below.

The sealing material constituting the solar cell module 10 is a sealing material disposed on either the light receiving surface side or the non-light receiving surface side of any solar cell element 6 including a non-light receiving surface side white sealing material described later. also, it a 0.870 g / cm ³ or more 0.930 g / cm ³ or less polyethylene resin as a base resin of the gel fraction is formed by the 0% of the resin film.

  The non-light-receiving surface side transparent sealing material 3 having a gel fraction of 0% can be formed as a thermoplastic sealing material as one embodiment. Further, as another embodiment, it may be formed as a weakly cross-linking type sealing material that causes a very weak cross-linking (weak cross-linking) that does not interfere with the film formation at the time of film formation and does not change the gel fraction. it can. “Weak cross-linking” is a production method disclosed in detail in International Publication No. 2011/152314, and is a known film-forming technique in which very weak cross-linking proceeds while maintaining the gel fraction at about 0%. It is. In this specification, the sealing material formed by obtaining this weak crosslinking treatment is referred to as a “weakly-crosslinked sealing material” or a “weakly crosslinked sealing material”. Even if it is based on any of the above production methods, at least in the meaning that the crosslinking of the material resin does not proceed after film formation, these are all “non-crosslinked sealing materials” in a broad sense. is there. In the solar cell module 10, the sealing material disposed on the light receiving surface side and the non-light receiving surface side of the solar cell element 6 is the “non-crosslinked sealing material” in this sense. It is one of the basic features of the composition.

As described above, the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed as a thermoplastic sealing material made of a sealing material composition that does not contain a crosslinking agent, as one embodiment. can do. In this case, the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 include a plurality of core layers 21 (31) and skin layers 22 (32) disposed on both outermost surfaces. It is preferable to make it the multilayer film comprised by these layers. In this case, the core layer 21 (31) preferably uses a polyethylene resin having a density of 0.910 g / cm ³ or more and 0.930 g / cm ³ or less as a base resin, and the skin layer 22 (32). is a less density 0.890 g / cm ³ or more 0.910 g / cm ^3, a density less than the density of the base resin for the core layer, preferably a lower density of the base resin and polyethylene resin It is preferable to do.

  As described above, when the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed as a thermoplastic multilayer film, the total thickness is preferably 250 μm or more and 600 μm or less, and 300 μm or more. More preferably, it is 550 μm or less. If the total thickness is less than 250 μm, the impact cannot be sufficiently mitigated. However, if the total thickness is 250 μm or more, for example, the light-receiving surface side sealing material 2 and the non-light-receiving surface side have a total thickness of about 250 μm. Even when the transparent sealing material 3 is thinned, the molding property and the heat resistance can be combined at a sufficiently preferable level. In addition, when the total thickness exceeds 600 μm, it is difficult to obtain an effect of further improving the impact mitigation effect, it is not possible to meet the demand for thinning the solar cell module, and it is uneconomical.

  In addition, the thickness of the core layer 21 (31) in the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 formed as the thermoplastic multilayer film may be 100 μm or more and 400 μm or less. Preferably, it is 250 μm or more and 350 μm or less. In this case, the thickness of each skin layer 22 (32) is not less than 30 μm and not more than 200 μm. By setting the thicknesses of the respective layers of the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 within such a range, the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 Heat resistance and molding characteristics can be maintained in a favorable range.

As above-mentioned, the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 can also be formed as a weak bridge type sealing material as other preferable embodiment. In this case, the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 have a density of 0.870 g / cm ^{3 to} 0.900 g / cm ³ as a base resin, and will be described later. It is preferable that it consists of a composition containing a very small amount of a crosslinking agent.

  When the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed as weakly cross-linking type sealing materials, the transparent sealing material may be a single-layer film, as shown in FIG. It may be a multilayer film constituted by the core layer 21 (31) and the skin layer 22 (32) disposed on both surfaces of the core layer. In this case, it is within the composition range of this sealing material composition for transparent sealing materials, which will be described later, and those having different compositions and component ratios can be used for each layer.

  When the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are made of a weakly crosslinked multilayer film, it is more preferable to use a sealing material having a different MFR for each layer. The transparent sealing material made of a weakly crosslinked resin film has preferable transparency, flexibility, and heat resistance even when it is a single layer film, but is a surface that is in close contact with the electrode surface of the solar cell element. Is more preferably excellent in such molding characteristics. This transparent sealing material, which is a multilayer film having a different MFR for each layer, is preferably used as a sealing material by disposing a layer having a high MFR in the outermost layer on the side to be used in close contact with the electrode surface of the solar cell element. While maintaining transparency and heat resistance, it is possible to further improve the molding characteristics on the contact surface with the solar cell element. As shown in the examples, the weakly crosslinked multilayer film is a non-crosslinked sealing material and is excellent in transparency, and therefore can be particularly preferably used as the light receiving surface side sealing material 2.

  For example, in the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 which are weakly crosslinked multilayer films composed of three or more layers, the thickness of the outermost layer is 30 μm or more and 200 μm or less. It is preferable. By doing in this way, while maintaining the preferable heat resistance as a sealing material, the preferable molding characteristic in an outermost layer can be provided, and also manufacturing cost can be suppressed low.

  The light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed into a film-like shape by molding a sealing material composition for transparent sealing material, which will be described in detail below, by a conventionally known method. It is a sheet. In addition, the sheet form in this invention means the film form, and there is no difference in both.

(Encapsulant composition for light-receiving surface side sealing material and non-light-receiving surface side transparent sealing material (transparent sealing material))
When the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed as thermoplastic sealing materials, the sealing material composition for the transparent sealing material used for the production of each layer is for each layer. The base resin is a composition having a different density range. Hereinafter, first, a sealing material composition that is preferably used when these sealing materials are formed as a thermoplastic sealing material will be described.

  In this case, the encapsulant composition for the transparent encapsulant comprises the encapsulant composition for the core layer 21 (31) and the encapsulant composition for the skin layer 22 (32), respectively. Use differently for formation. Then, by forming a multilayer film having a three-layer structure in which the skin layers are arranged on both outermost surfaces with a predetermined layer thickness by using the respective sealing material compositions for the core layer and the skin layer, 2 and the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 shown in FIG. 3 can be manufactured.

  As a base resin of the sealing material composition for the core layer 21 (31) of these transparent sealing materials, a low density polyethylene resin (LDPE), a linear low density polyethylene resin (LLDPE), or a metallocene direct resin is used. A chain low density polyethylene resin (M-LLDPE) can be preferably used. Among these, from the viewpoint of long-term reliability of the solar cell module, a low-density polyethylene resin (LDPE) can be particularly preferably used as the composition for the core layer.

The density of the polyethylene resin used as the base resin of the sealing material composition for the core layer 21 (31) is 0.910 g / cm ³ or more and 0.930 g / cm ³ or less, and more preferably 0.920 g / cm ^3. cm ³ or less. By setting the density of the base resin of the sealing material composition for the core layer 21 (31) within the above range, the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are not subjected to the crosslinking treatment. It can be provided with necessary and sufficient heat resistance.

  The melting point of the sealing material composition for the core layer 21 (31) is preferably 90 ° C. or higher and 135 ° C. or lower, and more preferably 100 ° C. or higher and 115 ° C. or lower. By setting the melting point of the core layer 21 (31) within the above melting point range, the heat resistance and molding characteristics of these transparent sealing materials can be maintained within a preferable range. In addition, it is possible to raise the melting | fusing point of a sealing material composition to about 135 degreeC by adding high melting point resin, such as a polypropylene, to the composition of a core layer.

  The melt mass flow rate (MFR) of the polyethylene-based resin used as the base resin of the encapsulant composition for the core layer 21 (31) is 2.0 g / 10 min or more and 7.5 g / min at 190 ° C. and a load of 2.16 kg. It is preferably 10 minutes or less, and more preferably 3.0 g / 10 minutes or more and 6.0 g / 10 minutes or less. By setting the MFR of the base resin of the sealing material composition for the core layer 21 (31) within the above range, the heat resistance and molding characteristics of these transparent sealing materials can be maintained within a preferable range. . Moreover, the processability at the time of film-forming can fully be improved, and it can contribute also to the improvement of productivity of the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3. In addition, about MFR in case a sealing material is a multilayer film, it measures by the said process with the multilayer state by which all the layers were laminated | stacked integrally, and the obtained measured value is the MFR value of the said multilayer sealing material. Shall be.

  Content of said base resin with respect to all the resin components in the sealing material composition for core layers 21 (31) is 70 to 99 mass%, Preferably it is 90 to 99 mass%. . As long as the base resin is included within the above range, other resins may be included.

  As a base resin of the sealing material composition for the skin layer 22 (32) of the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3, the sealing material composition for the core layer 21 (31) is used. Similarly, a low density polyethylene resin (LDPE), a linear low density polyethylene resin (LLDPE), or a metallocene linear low density polyethylene resin (M-LLDPE) can be preferably used. Among these, from the viewpoint of molding characteristics, a metallocene linear low density polyethylene resin (M-LLDPE) can be particularly preferably used as the composition for the skin layer.

The density of the polyethylene resin used as the base resin of the skin layer 22 (32) sealing material composition for is a 0.890 g / cm ³ or more 0.910 g / cm ³ or less, more preferably, 0. It is 899 g / cm ³ or less. By setting the density of the base resin of the sealing material composition for the skin layer within the above range, the adhesiveness of these transparent sealing materials can be maintained within a preferable range.

  About melting | fusing point of the sealing material composition for skin layers 22 (32), it is preferable that it is melting | fusing point 55 degreeC or more and 100 degrees C or less, and it is more preferable that it is melting | fusing point 80 degreeC or more and 95 degrees C or less. By making melting | fusing point of the sealing material composition for skin layers 22 (32) into the said range, the adhesiveness of the sealing material at the time of integration as a solar cell module can be improved further reliably.

  The melt mass flow rate (MFR) of the polyethylene-based resin used as the base resin of the sealing material composition for the skin layer 22 (32) is 2.0 g / 10 min or more and 7.0 g / min at 190 ° C. and a load of 2.16 kg. It is preferably 10 minutes or less, and more preferably 2.5 g / 10 minutes or more and 6.0 g / 10 minutes or less. By setting the MFR of the base resin of the sealing material composition for the skin layer 22 (32) within the above range, the adhesiveness of these transparent sealing materials can be more reliably maintained within a preferable range. Moreover, the processability at the time of film formation can fully be improved, and it can contribute to the improvement of productivity of the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3.

  Content of said base resin with respect to all the resin components in the sealing material composition for skin layers 22 (32) is 60 to 99 mass%, Preferably it is 90 to 99 mass%. . As long as the base resin is included within the above range, other resins may be included.

In the case where the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed as the above-mentioned weakly cross-linking type sealing material, the sealing material composition for the non-light-receiving surface side transparent sealing material used for this Uses a low density polyethylene (LDPE) having a density of 0.900 g / cm ³ or less, preferably a linear low density polyethylene (LLDPE) as a base resin. The linear low density polyethylene is a copolymer of ethylene and α-olefin, and in the present invention, the density is preferably 0.900 g / cm ³ or less, more preferably 0.870 g / cm ³ or more. The range is 0.890 g / cm ³ or less. If it is this range, favorable transparency and heat resistance can be provided by a weak crosslinking process, maintaining sheet workability.

  Further, when the light-receiving surface side sealing material 2 and the non-light-receiving surface side transparent sealing material 3 are formed as the above-mentioned weakly cross-linking type sealing material, the melt mass flow rate (MFR) of the polyethylene resin as the base resin is It is preferably 1.0 g / 10 min or more and 40 g / 10 min or less at 190 ° C. and a load of 2.16 kg, more preferably 2 g / 10 min or more and 40 g / 10 min or less. When the MFR is in the above range, it is possible to make the processability of these transparent sealing materials excellent when forming the film.

  When manufacturing these transparent sealing materials by a manufacturing method that imparts heat resistance by advancing weak crosslinking, with respect to all resin components of the sealing material composition for the non-light-receiving surface side transparent sealing material By adding 0.02 mass% or more and less than 0.5 mass% of the crosslinking agent, preferable heat resistance can be imparted to the non-light-receiving surface side transparent sealing material 3. When the addition amount of the cross-linking agent exceeds 0.5% by mass, a gel is generated during molding and the film forming property is lowered and the transparency is also lowered.

  There is no limitation in particular about the kind of crosslinking agent used for manufacture of said weak bridge | crosslinking type sealing material, The various crosslinking agents illustrated below can be used suitably. Specific examples of the crosslinking agent include various radical polymerization initiators exemplified below. Examples of the radical polymerization initiator include n-butyl 4,4-di (t-butylperoxy) valerate, ethyl 3,3-di (t-butylperoxy) butyrate, 2,2-di (t-butyl). Peroxyketals such as peroxy) butane, hydroperoxides such as diisopropylbenzene hydroperoxide, 2,5-dimethyl-2,5-di (hydroperoxy) hexane; di-t-butyl peroxide, t -Butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-peroxy) hexyne-3 Dialkyl peroxides such as bis-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, benzo Diacyl peroxides such as ruperoxide, o-methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide; t-butyl peroxyacetate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy Pivalate, t-butyl peroxy octoate, t-butyl peroxy isopropyl carbonate, t-butyl peroxy benzoate, di-t-butyl peroxy phthalate, 2,5-dimethyl-2,5-di (benzoyl peroxy) ) Peroxyesters such as hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne-3, t-butylperoxy-2-ethylhexyl carbonate; keto such as methyl ethyl ketone peroxide and cyclohexanone peroxide Organic peroxides such as peroxides, or azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile), dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctate, dioctyltin dilaurate And silanol condensation catalysts such as dicumyl peroxide.

  In the case of producing the non-light-receiving surface side transparent sealing material 3 by a production method that imparts heat resistance by advancing weak crosslinking, the crosslinking aid is used differently from general crosslinking treatment. Preferably not.

  Among the transparent sealing materials described above, it is more preferable to use metallocene linear low density polyethylene as the base resin of the sealing material composition for the light receiving surface side sealing material. Metallocene linear low density polyethylene is synthesized using a metallocene catalyst which is a single site catalyst. Such polyethylene has few side chain branches and a uniform comonomer distribution. For this reason, molecular weight distribution is narrow, it is possible to make it the above ultra-low density, and a softness | flexibility can be provided with respect to a sealing material. As a result of the flexibility imparted to the sealing material, the adhesion between the sealing material and glass, metal, or the like increases.

  In addition, linear low density polyethylene has a narrow crystallinity distribution and a uniform crystal size, so that not only a large crystal size does not exist, but also the crystallinity itself is low because of its low density. For this reason, it is excellent in transparency when processed into a sheet shape as a sealing material. Therefore, the incident in the case where the sealing material made of the sealing material composition for the light receiving surface side sealing material using this as a base resin is disposed between the light receiving surface side glass protective substrate 1 and the solar cell element 6. A decrease in power generation efficiency due to light attenuation can be prevented.

  In the encapsulant composition for all the transparent encapsulant layers described above, a silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer, if necessary, More preferably, each sealing material composition contains a certain amount. Such a graft copolymer increases the degree of freedom of silanol groups that contribute to the adhesive force, and therefore improves the adhesion of the non-light-receiving surface side transparent sealing material 3 to other members in the solar cell module. it can. The content of the silane-modified polyethylene resin encapsulant composition with respect to all resin components is 2 mass% or more and 20 mass% or less in the encapsulant composition for the core layer 21 (31), and the skin layer 22 ( In the sealing material composition for 32), it is preferable that they are 5 mass% or more and 40 mass% or less. In particular, it is more preferable that the encapsulant composition for the skin layer contains 10% or more of silane-modified polyethylene. In addition, it is preferable that the silane modification amount in said silane modified polyethylene resin is about 1.0 mass% or more and 3.0 mass% or less. The preferable content range of the silane-modified polyethylene resin in the sealing material composition is based on the premise that the silane-modified amount is within this range, and should be finely adjusted as appropriate according to the variation of the modified amount. Is desirable.

  Adhesiveness improvers can also be appropriately added to all of the encapsulant compositions for the transparent encapsulant layer. By adding the adhesion improver, the adhesion durability with other base materials can be made higher. As the adhesion improver, a known silane coupling agent can be used, and a silane coupling agent having an epoxy group or a silane coupling having a mercapto group can be particularly preferably used.

  It is preferable to add a light-resistant stabilizer to all encapsulant compositions for transparent encapsulants so as to capture radical species harmful to the polymer and prevent generation of new radicals. As the light-resistant stabilizer added to these sealing material compositions, a high molecular weight type hindered amine light-resistant stabilizer can be particularly preferably used.

  In general, many types of compounds are known as hindered amine light stabilizers from low molecular weight compounds to high molecular weight compounds. When used in a sealing material composition for a solar cell module, bleeding out often occurs when a low molecular weight, that is, a molecular weight of less than 1200 is used. In this case, the light transmittance is low. It becomes smaller and transparency is lowered. Since a decrease in the transparency of the encapsulant leads to a decrease in power generation efficiency of the solar cell module, it is preferable to use a high molecular weight molecular weight of 1200 or more as the light resistance stabilizer used in the encapsulant composition. As an example of a high molecular weight type hindered amine light stabilizer that can be preferably used, mention may be made of 1- [2- (4-hydroxy-2,2,6,6-tetramethylpiperidino) ethyl] butanedioate. Can do.

  The amount of hindered amine light resistance stabilizer added to the encapsulant composition may be 0.005% by mass or less and less than 0.2% by mass with respect to the total resin components in the encapsulant composition. It is preferable that they are mass% or more and 0.20 mass% or less. By making the content 0.005% by mass or more, the effect of stabilizing light resistance can be sufficiently obtained. Further, when the content is less than 0.2% by mass, bleeding out can be suppressed, and discoloration of the resin due to excessive addition of a hindered amine light-resistant stabilizer can also be suppressed.

  All the sealing material compositions for transparent sealing materials may further contain other components. For example, a crosslinking aid, an ultraviolet absorber, a heat stabilizer, an adhesion improver, a nucleating agent, a dispersant, a leveling agent, a plasticizer, an antifoaming agent, a flame retardant, and other various fillers can be added as appropriate. . The content ratio of these additives varies depending on the particle shape, density, and the like, but is preferably in the range of 0.001% by mass to 60% by mass in the encapsulant composition. By including these additives, it is possible to impart a mechanical strength that is stable over a long period of time, an effect of preventing yellowing, cracking, and the like to the encapsulant composition.

[Non-light receiving side white sealing material]
The non-light-receiving side white sealing member 4 is made a density 0.870 g / cm ³ or more 0.930 g / cm ³ or less of the polyethylene resin as the base resin, the gel fraction is formed by the 0% of the resin film It is preferable. This non-light-receiving surface side white sealing material 4 can also be formed as a thermoplastic or weakly crosslinked sealing material by the same material and manufacturing method as each of the transparent sealing materials described above.

  However, as shown in FIG. 4, the non-light-receiving surface side white sealing material 4 includes a plurality of layers including a white core layer 41 and a skin layer 42 disposed on at least one of the outermost surfaces. It is a multilayer film, and differs from each of the transparent sealing materials described above in that a coloring material is contained only in the white core layer 41.

  The non-light-receiving surface side white sealing material 4 which is a multilayer film has a resin composition similar to the sealing material composition for the core layer of each of the transparent sealing materials described above, and a white coloring material is further added thereto. A sealing material composition for the white core layer 41 and a sealing material composition for the skin layer 42 made of the same resin composition as the sealing material composition for the skin layer of each of the transparent sealing materials described above, It can be produced by molding a multilayer film having a three-layer structure in which skin layers are arranged on both outermost surfaces with a predetermined layer thickness by using each of these sealing material compositions. .

  The white core layer 41 in the non-light-receiving surface side white sealing material 4 constitutes a main part as a substrate layer in the non-light-receiving surface side white sealing material 4, and the non-light-receiving surface side white sealing material in this layer In the external appearance of No. 4, a colorant such as a white pigment for developing a white external appearance is contained. The non-light-receiving surface side white sealing material 4 can contribute to the improvement of power generation efficiency of the solar cell module 10 by reflecting sunlight in the white core layer 41 as described above.

(Sealing material composition for non-light-receiving surface side white sealing material)
The sealing composition for the white core layer of the non-light receiving surface side white sealing material 4 used for forming the white core layer 41 of the non-light receiving surface side white sealing material 4 is a non-light receiving surface side transparent sealing material. A low-density polyethylene resin having a predetermined density range similar to that of the sealing material composition for the core layer 31 is used as a base resin, and an inorganic white pigment such as titanium oxide is added thereto. .

  The sealing material composition for the white core layer of the non-light-receiving surface side white sealing material 4 contains a coloring material for expressing a preferable appearance and light reflection performance as a white sealing material. As such a coloring material, an inorganic white pigment made of an inorganic compound can be used. By including such a white pigment, when the white sealing material of the present invention is disposed on the non-light-receiving surface side of the solar cell module, the incident light into the solar cell module is reflected, and the solar cell module It is possible to improve the power generation efficiency. Further, when the white core layer 41 of the non-light-receiving surface side white sealing material 4 contains an inorganic white pigment, it not only has excellent light reflection performance in the visible light region, but also has an action of absorbing ultraviolet rays. Therefore, in the solar cell module 10 made of a glass substrate whose back side is transparent, the ultraviolet rays from the back side can be blocked to prevent the deterioration of each sealing material.

  As the inorganic white pigment, for example, calcium carbonate, barium sulfate, zinc oxide, titanium oxide and the like can be preferably used. Among these, titanium oxide can be particularly preferably used from the viewpoint of versatility.

  The white pigment preferably has a particle size of 0.2 μm or more and 1.5 μm or less. If the particle size of the white pigment is in the above range, the white layer formed from it effectively reflects near infrared rays in addition to the visible light region, so that the particles that can further contribute to the power generation efficiency improvement of the solar cell module. A typical example of a white pigment having a diameter of 0.3 μm or more and 1.5 μm or less is titanium oxide, and it is preferable to use titanium oxide as the white pigment in order to improve the reflection performance of sunlight. This inorganic white pigment is contained only in the white core layer 41, and the content in the white core layer 41 is preferably 5% by mass or more and 30% by mass or less. Moreover, the non-light-receiving surface side white sealing material 4 can suppress that the adhesiveness of the skin layer 42 falls by the influence of a white pigment by making a white pigment contain only in the white core layer 41. .

[Light-receiving side glass protective substrate, Non-light-receiving side glass protective substrate]
About the light-receiving surface side glass protective substrate 1 and the non-light-receiving surface side glass protective substrate 5, various glass plate materials conventionally used as a light-transmitting substrate material constituting the solar cell module can be used without particular limitation. it can.

  While the present invention has been specifically described with reference to the embodiment, the present invention is not limited to the above embodiment, and can be implemented with appropriate modifications within the scope of the present invention.

<Manufacture of sealing material>
EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

[Production of transparent sealing material (thermoplastic: sealing material A1)]
The encapsulant composition raw materials described below are mixed in the following proportions (parts by mass), and the encapsulant composition for the core layer and the encapsulant composition for the skin layer of the encapsulant of Examples and Comparative Examples, respectively. It was a thing. Using each sealing material composition for a core layer and a skin layer at an extrusion temperature of 210 ° C. and a take-off speed of 1.1 m / min using a φ30 mm extruder and a film molding machine having a 200 mm wide T-die Each resin film was produced, these each resin film was laminated | stacked, and the thermoplastic sealing material provided with the core layer and the skin layer arrange | positioned on both outermost surfaces was manufactured. This was made into sealing material A1 used as a transparent sealing material in the solar cell module of an Example and a comparative example. The thicknesses of the sealing materials are all 450 μm in total, and the thickness ratio of each layer is such that the skin layer: core layer: skin layer thickness ratio is 1: 8: 1. did. The density of the core layer of this multilayer sheet is 0.92 g / cm ³ , and the density of the skin layer is 0.89 g / cm ³ .

The following raw materials were used as the thermoplastic sealing material composition raw material.
(Base resin for encapsulant composition for core layer)
A metallocene linear low density polyethylene resin (M-LLDPE) having a density of 0.919 g / cm ³ , a melting point of 105 ° C., and an MFR at 190 ° C. of 3.5 g / 10 min. 77 parts by mass added.
A metallocene linear low-density polyethylene resin (M-LLDPE) having a density of 0.880 g / cm ³ , a melting point of 60 ° C., and an MFR at 190 ° C. of 3.5 g / 10 min. Added 20 parts by weight.
(Base resin for encapsulant composition for skin layer)
Metallocene linear low density polyethylene resin (M-LLDPE) having a density of 0.898 g / cm ³ , a melting point of 90 ° C., and an MFR at 190 ° C. of 3.5 g / 10 min. 85 parts by mass added.
(Other additives)
Weatherproofing agent master batch: Hindered amine light for 100 parts by weight of base resin (density 0.919 g / cm ³ , melting point 105 ° C., MFR at 190 ° C. is 3.5 g / 10 min low density polyethylene resin) Stabilizer (“KEMISTAB62” (Chemipro)): 0.6 parts by mass. UV absorber ("KEMISORB 12" (manufactured by Chemipro)): 3.5 parts by mass. UV absorber (“KEMISORB 79” (Chemipro): 0.6 parts by mass. The weathering agent master badge was added to the composition for the core layer and the skin layer by 10 parts by mass.
Silane-modified polyethylene resin: 2 parts by mass of vinyltrimethoxysilane with respect to 100 parts by mass of a metallocene linear low-density polyethylene resin having a density of 0.900 g / cm ³ and an MFR of 2.0 g / 10 min. A silane-modified polyethylene resin obtained by mixing 0.15 parts by mass of dicumyl peroxide as a radical generator (reaction catalyst), melting and kneading at 200 ° C. Density 0.901 g / cm ³ , MFR 1.0 g / 10 min. Melting point 100 ° C. The silane-modified polyethylene resin was added in an amount of 3 parts by mass to the core layer composition and 15 parts by mass of the skin layer composition.

[Manufacture of transparent sealing material (weak crosslinking system: sealing material A2)]
The encapsulant composition raw materials described below were mixed at the following blending ratios, and the encapsulant composition for the core layer of the encapsulant and the encapsulant composition for the skin layer of Examples and Comparative Examples, respectively. . Using each sealing material composition for a core layer and a skin layer at an extrusion temperature of 210 ° C. and a take-off speed of 1.1 m / min using a φ30 mm extruder and a film molding machine having a 200 mm wide T-die Each resin film was produced, and each of these resin films was laminated to produce a weakly-crosslinked sealing material including a core layer and a skin layer disposed on both outermost surfaces. This was made into sealing material A2 used as a transparent sealing material in the solar cell module of an Example and a comparative example. The thicknesses of the sealing materials are all 450 μm in total, and the thickness ratio of each layer is such that the skin layer: core layer: skin layer thickness ratio is 1: 8: 1. did.

The following raw materials were used as raw materials for the weakly crosslinked encapsulant composition.
(Base resin for encapsulant composition for core layer)
2,5-dimethyl-2,5-di (t-butylperoxy) with respect to 100 parts by mass of M-LLDPE pellets having a density of 0.880 g / cm ³ and MFR at 190 ° C. of 3.5 g / 10 min Compound pellets were obtained by impregnating 0.041 parts by mass of hexane. 97 parts by mass added.
(Base resin for encapsulant composition for skin layer)
2,5-dimethyl-2,5-di (t-butylperoxy) with respect to 100 parts by mass of M-LLDPE pellets having a density of 0.880 g / cm ³ and MFR at 190 ° C. of 3.5 g / 10 min Compound pellets were obtained by impregnating 0.032 parts by mass of hexane. Add 80 parts by weight.
(Other additives)
Weathering agent master batch: 3.8 parts by mass of benzophenol UV absorber and hindered amine light stabilizer 5 with respect to 100 parts by mass of powder obtained by pulverizing Ziegler linear low density polyethylene having a density of 0.880 g / cm ³ Mass parts and 0.5 parts by mass of a phosphorous heat stabilizer were mixed, melted, processed, and pelletized to obtain a master batch. The weathering agent master badge was added in an amount of 5 parts by mass to the core layer and skin layer compositions.
With respect to 98 parts by mass of a metallocene linear low density polyethylene (M-LLDPE) having a density of 0.881 g / cm ³ and an MFR at 190 ° C. of 2 g / 10 minutes, , 0.1 part by mass of dicumyl peroxide as a radical generator (reaction catalyst), mixed and melted and kneaded at 200 ° C., density 0.884 g / cm ³ , MFR at 190 ° C. was 1.8 g / A silane-modified transparent resin of 10 minutes was obtained. 3 parts by mass of the silane-modified polyethylene resin was added to the composition for the core layer and 15 parts by mass to the composition for the skin layer. The density of the core layer of this multilayer sheet is 0.88 g / cm ³ , and the density of the skin layer is 0.88 g / cm ³ .

[Manufacture of transparent sealing material (crosslinking system: sealing material B)]
Solar cell modules of Examples and Comparative Examples by mixing and melting a sealing material composition for a light-receiving surface side transparent sealing material having the following composition, and forming a film to a thickness of 450 μm by a conventional T-die method A single-layer cross-linking encapsulant B used as a transparent encapsulant was obtained. The film forming temperature was 90 ° C. to 100 ° C.
Base resin (LLDPE): a copolymer of ethylene and 1-hexene, having a density of 0.880 g / cm ³ and a melt mass flow rate (MFR) at 190 ° C. of 8 g / 10 min. polyethylene. Number average molecular weight of 77,000 in terms of polystyrene.
Cross-linking agent (TBEC): t-butylperoxy-2-ethylhexyl carbonate (manufactured by Arkema Yoshitomi, trade name Luperox TBEC). 0.7 parts by mass added to 100 parts by mass of the base resin.
Crosslinking aid (TAIC): triallyl isocyanurate (manufactured by Statomer, trade name SR533). 0.5 parts by mass added to 100 parts by mass of the base resin.
UV absorber: manufactured by Chemipro Kasei Co., Ltd., trade name KEMISORB102. Addition of 0.25 parts by mass to 100 parts by mass of the base resin.
Weathering stabilizer: Ciba Japan Co., Ltd., trade name Tinuvin 770. 0.2 parts by mass added to 100 parts by mass of the base resin.
Antioxidant: Ciba Japan Co., Ltd., trade name Irganox 1076. 0.05 parts by mass added to 100 parts by mass of the base resin.
Silane coupling agent: Shin-Etsu Chemical Co., Ltd., trade name KBM503. 0.05 parts by mass added to 100 parts by mass of the base resin.

[Non-light-receiving surface side white sealing material (production of C1, C2, C3]
The core layer in each of the thermoplastic, weakly cross-linked, and cross-linked encapsulating materials (for the encapsulating material B, a single-layered resin layer) with respect to 100 parts by mass of the following white pigment Three kinds of white sealing materials were manufactured by mixing in the ratio of 7 mass parts. The thermoplastic white sealing material thus obtained was designated as C1, the weakly crosslinked white sealing material as C2, and the crosslinked white sealing material as C3.
(White pigment)
Titanium oxide with an average particle size of 0.2 μm.

[Manufacture of transparent sealing material (thermoplastic (high density): sealing material A1c)]
The composition for the core layer of the thermoplastic sealing material A1 formed into a single-layer film having a thickness of 450 μm by the above molding method was designated as the sealing material A1c.

[Manufacture of transparent sealing material (thermoplastic (low density): sealing material A1s)]
The composition for the skin layer of the thermoplastic encapsulant A1 made into a single-layer film having a thickness of 450 μm by the above molding method was designated as encapsulant A1s.

[Measurement of gel fraction]
In order to evaluate the physical properties of each sealing material in an integrated state as a solar cell module, the above-mentioned measurement was performed for each sealing material sandwiched between ETFE films and subjected to crosslinking treatment by vacuum heating lamination. The gel fraction was measured by the method. As a result, the gel fraction of the cross-linking encapsulant C and the white encapsulant C3 is 60%. For the thermoplastic and weakly crosslinked sealing materials A1 and A2, and C1 and C2, the gel fraction after the heat treatment was 0%. The vacuum heating lamination conditions were the same as the conditions in the following “Manufacturing of solar cell module evaluation sample”.

<Manufacture of solar cell module evaluation samples>
Each of the sealing materials A1, A2, and B is used as a light receiving surface side transparent sealing material or a non-light receiving surface side transparent sealing material, respectively, and each of the sealing materials C1 to C3 is respectively Samples for solar cell module evaluation of each example and comparative example were manufactured according to the configuration shown in Table 1 below by properly using the non-light-receiving surface side white sealing material.

Samples for solar cell module evaluation include a light-receiving surface side glass protective substrate (white plate tempered glass, 1700 mm × 1000 mm × 2.5 mm), a light-receiving surface side transparent sealing material (1700 mm × 1000 mm × 0.45 mm), a solar cell element, Non-light receiving surface side transparent sealing material (1700 mm × 1000 mm × 0.45 mm), non-light receiving surface side white sealing material (1700 mm × 1000 mm × 0.45 mm), and non-light receiving surface side glass protective substrate (white plate float tempered glass, 1700 mm × 1000 mm × 2.5 mm) are sequentially laminated and then manufactured by thermocompression bonding using the above-mentioned members as an integrally molded body by vacuum heating lamination, and this is evaluated for solar cell modules of Examples and Comparative Examples. A sample was used. Regarding the solar cell elements, the following solar cell elements were prepared, and 60 solar cell elements of the same type were electrically connected in series with a connecting member for one solar cell module evaluation sample.
(Vacuum heating lamination conditions) (a) Vacuum drawing: 6.0 minutes
(B) Pressurization (0 kPa to 70 kPa): 1.5 minutes
(C) Pressure holding (70 kPa): 11.0 minutes
(D) Temperature 165 ° C
(Solar cell element)
A crystalline silicon solar cell element manufactured using a polycrystalline silicon substrate. (Motech, IM156B3)

<Evaluation of solar cell element protection performance during laminating>
About each said solar cell module evaluation sample, it measured with the EL light emission tester, and evaluated the protective performance of the solar cell element at the time of a lamination process. The evaluation results are shown in Table 1 as “cell cracking”.

(Evaluation criteria) ○: No cracks on the entire surface of all solar cell elements
Δ: There is a crack in a part of the surface of the solar cell element, but light emission can be confirmed.
×: There is a place where light emission cannot be confirmed due to cracks

<Evaluation of wraparound effect during laminating>
About each said solar cell module evaluation sample, the wraparound suppression effect test was evaluated by visual observation by the following evaluation criteria. The evaluation results are shown as “wraparound” in Table 1.
(Evaluation criteria) (circle): The white sealing material does not wrap around to the light-receiving surface side of a solar cell element.
X: The white sealing material wraps around the light-receiving surface side of the solar cell element.

<Evaluation of residual amount of residual bubbles between layers during lamination>
About each said solar cell module evaluation sample, the residual amount of the interlayer residual bubble was evaluated by visual observation by the following evaluation criteria. The evaluation results are shown as “bubbles” in Table 1.
(Evaluation criteria) ○: No bubbles remain at the interface between any of the glass protective substrates and the sealing material.
×: One or more bubbles having a diameter of 5 mmφ or more remain at the interface between any glass protective substrate and the sealing material.

<Evaluation of heat resistance of sealing material>
A heat-resistant creep test was performed to measure the heat resistance of each encapsulant. A glass plate (white plate float semi-tempered glass JPT3.2 150 mm × 150 mm × 3.2 mm), each of the sealing materials A, B1, B2, C1 to C3 cut out to 5 cm × 7.5 cm is placed on top of each other. From the top, the same glass plate as in Evaluation Example 1 of 5 cm × 7.5 cm was placed on top of each other, subjected to vacuum heating laminator treatment under the same conditions as in the above <Manufacture of solar cell module evaluation sample>, and a heat resistance evaluation sample was prepared. . Thereafter, the large format glass was placed vertically and allowed to stand at 105 ° C. for 12 hours, and the moving distance (mm) of the 5 cm × 7.5 cm glass plate after the standing was measured and evaluated. Evaluation was performed according to the following criteria. The evaluation results are shown in Table 2 as “heat resistance”.
(Evaluation criteria) ○: More than 0.00mm and less than 1.0mm
X: 1.0 mm or more The evaluation results are shown in Table 2 as “heat resistance”.

<Transparency evaluation of sealing material>
In order to evaluate the transparency of each sealing material, the haze value (JIS K7136) was measured. The measurement was carried out with Murakami Color Research Laboratory Haze / Transmittance HM150 in accordance with JISK7136 in the state where blue sheet glass was laminated on the top and bottom of each sealing material. The evaluation results are shown in Table 2 as “transparency”.
(Evaluation criteria) ○: Less than 10.0%
Δ: 10.0% or more

  From Tables 1 and 2, the solar cell module of the present invention is a double-sided glass protective substrate type solar cell module that is excellent in durability and barrier properties, while maintaining sufficient heat resistance, and the white portion wraps around during lamination. It is a double-sided glass protective substrate type solar cell module that is sufficiently suppressed and suppresses unnecessary bubbles derived from gas generated from the sealing material in the module, and has superior quality stability than conventional products. I understand.

DESCRIPTION OF SYMBOLS 1 Light-receiving surface side glass protective substrate 2 Light-receiving surface side sealing material 21 Core layer 22 Skin layer 3 Non-light-receiving surface side transparent sealing material 31 Core layer 32 Skin layer 4 Non-light-receiving surface side white sealing material 41 White core layer 42 Skin Layer 5 Non-light-receiving surface side glass protective substrate 6 Solar cell element 10 Solar cell module

Claims (6)

A double-sided glass protective substrate type solar cell module in which a light-receiving surface side glass protective substrate, a light-receiving surface side sealing material, a solar cell element, a non-light-receiving surface side transparent sealing material, and a non-light-receiving surface side glass protective substrate are sequentially laminated. Because
The light receiving side sealing material and the non-light receiving side transparent encapsulant made as either 0.870 g / cm ³ or more 0.930 g / cm ³ or less polyethylene resin as a base resin of a gel fraction of 0 %, A multi-layer encapsulant comprising a plurality of layers including a core layer and a skin layer having a density equal to or less than the density of the core layer and disposed on the outermost surface of the encapsulant. , Solar cell module.   In the non-light-receiving surface side transparent sealing material, the core layer has a thickness of 100 μm or more and 600 μm or less, the melting point of the core layer is 90 ° C. or more and 135 ° C. or less, and the thickness of each layer of the skin layer is respectively The solar cell module according to claim 1, wherein the skin layer has a melting point of not less than 30 µm and not more than 200 µm, and the melting point of the skin layer is not less than 55 ° C and not more than 100 ° C. The light receiving side sealing material, comprising a density of 0.870 g / cm ³ or more 0.900 g / cm ³ or less of the polyethylene resin as a base resin, a sealing material of a gel fraction of 0% of the weak cross-linking system according Item 3. The solar cell module according to Item 1 or 2.   The silane copolymer formed by copolymerizing α-olefin and an ethylenically unsaturated silane compound as a comonomer is contained in the light-receiving surface side sealing material and the non-light-receiving surface side transparent sealing material. To 4. The solar cell module according to any one of 3 to 4. Between the non-light-receiving surface side transparent sealing material and the non-light-receiving surface side glass protective substrate, a non-light-receiving surface side white sealing material is further laminated,
The non-light-receiving surface side white sealing material is a multilayer sealing material composed of a plurality of layers including a white core layer and a skin layer disposed on the outermost surface, and only the white core layer. The solar cell module in any one of Claim 1 to 4 in which the white coloring material is contained.   The non-light-receiving surface side white sealing material has a core layer thickness of 100 μm to 600 μm, a melting point of the core layer of 90 ° C. to 120 ° C., and a skin layer thickness of 30 μm to 200 μm. The solar cell module according to claim 5, wherein the skin layer has a melting point of 70 ° C. or higher and 100 ° C. or lower.

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