WO2007088892A1

WO2007088892A1 - Backside protective substrate for solar cell module, solar cell module and electric power generator

Info

Publication number: WO2007088892A1
Application number: PCT/JP2007/051604
Authority: WO
Inventors: Tamio Kawasumi; Yuji Matsui; Minoru Hoshino; Hiroyasu Kido
Original assignee: Mitsui Chemicals, Inc.
Priority date: 2006-02-02
Filing date: 2007-01-31
Publication date: 2007-08-09
Also published as: JPWO2007088892A1; TW200735389A; JP4809374B2

Abstract

Disclosed is a backside protective substrate for solar cell modules, which is excellent in mechanical characteristics while effectively suppressing bending. Specifically disclosed is a backside protective substrate for solar cell modules, which is composed of a structure having at least three layers, namely a layer (A) having a longitudinal elastic coefficient of not less than 500 kgf/mm2 but not more than 10,000 kgf/mm2, a layer (B) having a longitudinal elastic coefficient of not less than 10 kgf/mm2 but less than 500 kgf/mm2, and a layer (A') having a longitudinal elastic coefficient of not less than 500 kgf/mm2 but not more than 10,000 kgf/mm2. The structure has a weight per unit area of not less than 0.5 kg/m2 but not more than 10 kg/m2.

Description

Back surface protection substrate for solar cell module, solar cell module and power generator

Technical field

TECHNICAL FIELD [0001] The present invention relates to a back surface protection substrate for a solar cell module excellent in bending rigidity, insulation and light weight, and a solar cell module and a power generator using the same. Background art

[0002] As global environmental problems and energy problems become more serious, solar cells are attracting attention as energy sources that are clean and free from drought. When solar cells are used outdoors such as on the roof of a building, they are generally used in the form of solar cell modules.

[0003] Solar cell modules are usually formed by sandwiching and stacking solar cells made of polycrystalline silicon or the like with a sealing resin layer that also has ethylene blu-acetate (EVA) and the like. It has a structure covered with a protective substrate for use. That is, a typical solar cell module is a solar cell module protective substrate (surface protective sheet).

) Z-encapsulated resin layer Z solar cell Z-encapsulated resin layer Z It has a laminated structure called a protective substrate for the solar cell module (back surface protective substrate). As a result, the solar cell module has weather resistance and is suitable for outdoor use such as a roof portion of a building.

[0004] As a back surface protection substrate for a solar cell module, a metal plate such as aluminum whose surface has been insulated has been widely used since it has a certain degree of rigidity as a substrate and an excellent barrier property to moisture. It was done. However, it is difficult to make the insulating layer on the surface sufficiently thick due to cost restrictions. As a result, when friction, impact, etc. are applied, the insulating layer may be damaged, leading to insulation breakdown. In addition, when using a metal plate, it is necessary to increase the thickness of the metal plate in order to design a particularly large solar cell module, but there is a problem that the weight increases. This has limited the conditions for manufacturing and using conventional solar cell modules.

[0005] Instead of metal with an insulating surface, organic polymer with excellent insulation and high flexibility The use of powerful films as backside protection substrates for solar cell modules is being studied. While high insulation can be achieved using organic polymers, mechanical properties may not always be sufficient, and there is a tendency for greater deflection than with metals, so countermeasures are necessary. It is. In order to improve the mechanical properties, for example, it has been proposed to add a reinforcing fiber to the organic polymer (see, for example, JP 2001-68695 A and JP 2001-68701 A).

Patent Document 1: JP 2001-68695 A

Patent Document 2: Japanese Patent Laid-Open No. 2001-68701

Disclosure of the invention

Problems to be solved by the invention

[0006] However, the mechanical properties of the conventional back protective sheet having organic polymer strength with the addition of reinforcing fibers are not necessarily sufficient in relation to the purpose, and it is possible to effectively suppress the deflection. It was desired.

Means for solving the problem

[0007] As a result of intensive investigations, the inventors have a specific layer structure, and have a structural strength that has a bending rigidity, a weight per area, and a breakdown voltage in a specific range. It has been found that the substrate is excellent in mechanical properties and the deflection is effectively suppressed, and as a result, is suitable for use as a back surface protection for a solar battery module.

[0008] That is, the first invention of the present invention,

(1) Longitudinal elastic modulus of 500 kgfZmm ² or more lOOOOkgfZmm ² or less (A layer), longitudinal elastic modulus of lOkgfZmm ² or more and less than 500 kgfZmm ² (B layer), and longitudinal elastic modulus of 500 kgf / mm ² or more A back surface protection substrate for a solar cell module including a structure having at least three layers of 10000 kgf / mm ² or less (Α ′ layer), and the weight per area of the structure is 0.5 kgZm ² or more lOkgZm ^{The present invention} relates to a back surface protection substrate for a solar cell module that is ² or less. Here, “consisting of” means that the entire back surface protection substrate for the solar cell module is composed of the structure, and a part of the back surface protection substrate for the solar cell module is the structure. Including both It is the purpose.

[0009] Hereinafter, (2) to (22) are each one of preferred embodiments of the present invention.

[0010] (2) The A layer, the B layer, and the A ′ layer are laminated in this order, and the longitudinal elastic modulus of the A layer and the A ′ layer is 10 times or more the longitudinal elastic modulus of the B layer. The back surface protective substrate for a solar cell module as described in (1) above.

[0011] (3) A composite material layer in which at least one of the A layer and the A 'layer contains a thermoplastic resin and a reinforcing fiber, and the volume content of the reinforcing fiber is 30% or more and 85% or less. The back protective substrate for a solar cell module according to (1) or (2) above.

[0012] (4) The above-described (B), wherein the B layer contains a thermoplastic resin substantially the same as the thermoplastic resin.

The back surface protection board for solar cell modules as described in 3).

[0013] (5) The back surface protective substrate for a solar cell module according to the above (3) or (4), wherein the thermoplastic resin is a propylene-based (co) polymer.

[0014] (6) The back surface protective substrate for a solar cell module according to (3) to (5), wherein the B layer contains a propylene-based (co) polymer.

[0015] (7) The back protective substrate for a solar cell module according to (6), wherein the reinforcing fiber is glass fiber or carbon fiber.

[0016] (8) The back surface protective substrate for a solar cell module according to (3) to (7), wherein the reinforcing fiber is treated with a coupling agent!

[0017] (9) At least a part of the reinforcing fibers are converged and arranged in one direction.

The back protective substrate for a solar cell module according to any one of (3) to (8) above.

[0018] (10) The back surface protection substrate for a solar cell module according to (1) to (6), wherein the B layer is a layer having a resin foam strength.

[0019] (11) Further, a layer (C layer) including a material having a deformation amount of 4% or less in a section from 30 ° C to 100 ° C at the time of TMA measurement, and the A layer, B Layer, A ′ layer, and C layer are laminated in this order, and the longitudinal elastic modulus E (kgfZmm ² ) of the C layer and the C layer

C

従Tsu and the linear expansion coefficient ^{CTE (10- 6 Z ° C)} , since the thickness h (mm) of the C layer to the following formula (A)

C C

Guided Te, film coefficient Fc of the C layer (10- ⁶ kgfZmm ° C) is, meet the relation of the following formula (B), the (2) - (10) a solar cell module for the back protection according to substrate. Formula (A): F = EX CTE X h

c c c c

Formula (B): 1000 (10 " ⁶ kgf / mm ° C) ≤F ≤ lOOOO (10" ⁶ kgf / mm ° C)

c

[0020] (12) The back surface protective substrate for a solar cell module according to (11), wherein the C layer comprises a propylene-based (co) polymer.

[0021] (13) having said propylene (co) polymer strength 97 mole ^_0/0 or more constitutional units derived from propylene, and has a Aisotakuchikku structure, the back surface for a solar cell module according to (12) Protective board.

[0022] (14) The back protective substrate for a solar cell module according to (12) or (13), wherein the C layer is not substantially stretched.

(15) The back protective substrate for a solar cell module according to (11) to (14), wherein the C layer is bonded to the A ′ layer with a curable adhesive or a crosslinkable resin. .

(16) The C layer is described in (11) to (14) above, wherein the C layer is adhered to the A ′ layer by a layer comprising a crosslinkable ethylene-vinyl acetate copolymer. Back surface protection board for solar cell modules.

[0025] (17) A solar cell module comprising the back protective substrate for a solar cell module according to (1) to (16).

(18) Surface protection sheet for solar cell module (I), encapsulant layer (II), solar cell (I II), encapsulant layer (IV), and (1) to (16 The solar cell module according to (17), wherein the back surface protective substrate (V) for solar cell module according to (8) is laminated directly or indirectly in this order.

[0027] (19) The back surface protection substrate (V) for the solar cell module further has a deformation amount of 4% or less and a longitudinal elastic modulus of lOOkgfZmm ² or more in the section of 30 ° C force at 100 ° C during TMA measurement. A layer including a material (C layer), and the A layer, B layer, A ′ layer, and C layer are laminated in this order, and the A layer is on the sealing material layer (IV) side The solar cell module according to (18), which is located in

[0028] (20) The thickness h (mm) of the surface protection sheet (I) for the solar cell module and the thickness h (mm) of the C layer are 0.5≤h / h≤2.0. The solar c CI described in (19) above that satisfies the above conditions

Battery module. [0029] (21) Surface protection sheet for solar cell module (I)

) And the solar cell module surface protective sheet (I) linear expansion coefficient CT ^ and (10- ⁶ / ° C), the thickness h (mm) from the following equation of the solar cell module surface protective sheet (I) Film coefficient F (10 " ⁶ k gf / mm ° C) of the surface protection sheet for solar cell module (I), which is guided according to (1),

The longitudinal elastic modulus E (kgfZmm ² ) of the C layer and the linear expansion coefficient CTE (10

C C

° C) and the thickness h (mm) of the C layer, which is derived according to the following formula (2):

C

Coefficient F (10 " ⁶ kgf / mm ° C) and the surface protection sheet (I) for the solar cell module

C

Met Lum coefficient F (10- ⁶ kgfZmm ° C) and the ratio of (F ZF) forces under formula the relationship (3), the (

I C I

The solar cell module according to 19) or (20).

Formula (1): F = E X CTE X h

Formula (2): F = E X CTE X h

c c c c

Formula (3): 0. 7≤F / F≤l. 3

C I

[0030] (22) A power generation device having the solar cell module according to (17) to (21).

[0031] The second invention of the present invention is

(23) Surface protection sheet for solar cell module (I), encapsulant layer (II), solar cell (I II), encapsulant layer (IV), and back surface protection for solar cell module having a laminated structure The board (V) is laminated directly or indirectly in this order,

Wherein the modulus of longitudinal elasticity E of the solar cell module surface protective sheet (I) (kgfZmm ^2), and the linear expansion coefficient of the previous SL solar cell module surface protective sheet ^{(I) CTE (10- 6 Z} ° C), before The film coefficient F (10 " ⁶ kgf / mm ° of the surface protection sheet for solar cell module (I) derived from the thickness (mm) of the surface protection sheet for solar cell module (I) according to the following formula (1) C) and

Longitudinal elastic modulus E (kgfZmm ² ) of the layer (C layer) on the side opposite to the side in contact with the sealing material layer (IV) of the back surface protection substrate (V) for the solar cell module, and the line of the C layer Expansion coefficient CTE

C

(10 "V ° C) and the thickness h (mm) of the C layer, which is derived according to the following formula (2).

C C

Less than the ratio of the film coefficient of the layer ^{F (10- 6 kgfZmm ° C)} (F ZF) forces under formula the relationship (3)

C C I

The present invention relates to a solar cell module. Formula (1): F = EX CTE X h

Formula (2): F = E X CTE X h

c c c c

Formula (3): 0. 7≤F / F≤l. 3

C I

[0032] Further, the third invention of the present invention is

(24) including a laminate in which at least three layers are laminated,

The present invention relates to a back surface protection substrate for a solar cell module, wherein the laminate has a composite material layer containing at least one layer of thermoplastic resin and reinforcing fiber, and a layer having a resin foam strength.

The invention's effect

[0033] According to the present invention, it is possible to provide a back surface protection substrate for a solar cell module that is excellent in mechanical properties and in which deflection is effectively suppressed. Less board deflection can greatly improve workability during module installation, reduce stress caused by module deflection that can occur at the same time, and suppress deflection after module installation. As a result, it is possible to reduce the stress applied to the modules that are applied during snowfall and strong winds that occur after construction. A solar cell module and a power generation device manufactured using such a protective substrate for a solar cell module are excellent in strength, lightness, lifetime, stability, etc., and are particularly suitable for outdoor use, and are practical. High value.

Brief Description of Drawings

FIG. 1 is a cross-sectional view schematically showing an example of the structure of a back surface protection substrate for a solar cell module that is a preferred embodiment of the present invention.

FIG. 2 is a view showing an example of a method for measuring deflection and bending rigidity of a back surface protective film for a solar cell module which is a preferred embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0035] back surface protective substrate for a solar cell module of the present invention, the modulus of longitudinal elasticity is 500KgfZmm ² or more LOOOOkgfZmm ² or less layers (A layers), modulus of longitudinal elasticity is less than LOkgfZmm ² or more 500k gfZmm ² layers (B layers ), And a back surface protection substrate for a solar cell module, including a structure having at least three layers (Α ′ layers) having a longitudinal elastic modulus of 500 kgfZmm ² or more and lOOOOkgf Zmm ² or less, the area of the structure weight per is 0. 5kg / m ² or more 10 It is a back surface protection substrate for solar cell modules, which is kg / m ² or less. In the back surface protection substrate for a solar cell module of the present invention, the dielectric breakdown voltage of the structure is preferably 10 kV or more. In the back surface protective substrate for a solar cell module of the present invention, it is preferable that the flexural rigidity per 1000 mm width of the structure is 1. OX 10 ⁶ to 10 × 10 ⁶ kgf′mm ² or more.

[0036] A back surface protection substrate for a solar cell module having a layer structure composed of a plurality of layers having the above specific longitudinal elastic modulus and having a structural power whose weight per area is in the above specific range, Since it has excellent mechanical properties and deflection is particularly effectively suppressed, it is particularly suitable as a back surface protection substrate for large-sized solar cell modules. It is also easy to reduce the weight, and it is easy to operate the solar cell normally and stably.

[0037] The best mode for carrying out the present invention will be sequentially described below.

(Structure with 3 layers of A, B, and A ')

Structure constituting the back protective substrate for a solar cell module of the present invention, at least a longitudinal elastic coefficient is 500KgfZmm ² or more LOOOOkgfZmm ² below A layer, longitudinal elastic modulus is less than 1 OkgfZmm ² or more 500kgfZmm ² B layer and the vertical It has three layers of A and layer whose elastic modulus is 500 kgfZmm 2 or more and 1 OOOOkgf Zmm ² or less.

[0038] By having these three layers, deflection is effectively suppressed while maintaining the weight per specific area, which is another requirement of the structure constituting the back protective substrate for the solar cell module of the present invention. The manufactured back surface protection substrate for a solar cell module can be manufactured relatively easily.

[0039] The order of stacking of the A layer, the B layer, and the A 'layer is not particularly limited, but sufficient bending rigidity is exhibited on both the upper side and the lower side of the back surface protection substrate for the solar cell module of the present invention. Therefore, it is preferable that the A layer, the B layer, and the A ′ layer are laminated in this order. It is preferable from the viewpoint of preventing warpage that the A layer, the B layer, and the A ′ layer are laminated in this order.

[0040] The A layer and the A 'layer may be the layers having the same thickness and physical properties, or may be different from each other. The A ′ layer is preferably the same. In addition, warping of the back surface protection substrate for solar cell modules is prevented. In terms of stopping power, it is preferable that the A layer and the A ′ layer have the same or at least substantially the same longitudinal elastic modulus and thickness. For example, it is preferable that the thickness of the A layer is ZA, and the thickness of the layer is in the range of 0.5 to 2.0. The longitudinal elastic modulus of the A layer is 0.5 to 2. It is preferably within the range of 0. When such a condition is satisfied, warping during the lamination molding of the back surface protection substrate for the solar cell module can be effectively prevented. Further, the linear expansion coefficient of the A layer is preferably in the range of 0.5 to 2.0. When such conditions are satisfied, warpage due to temperature changes can be effectively prevented. When these ranges are exceeded, it may be necessary to take measures to prevent warping during the production of the laminate.

[0041] The structure constituting the back surface protection substrate for the solar cell module of the present invention has at least three layers of A layer, B layer, and A 'layer, and has other layers. You may or may not have. From the viewpoint of simplifying the structure and achieving low cost, there is no layer other than the A layer, B layer and A 'layer, and the three layers A layer, B layer and A' layer are directly bonded. From the standpoint of imparting many functions to the preferred structure, it is preferable to have layers other than the A layer, the B layer and the A ′ layer. Examples of the layer other than the A layer, the B layer, and the A ′ layer include, but are not limited to, an adhesive layer, a gas barrier layer, a design layer, and the like.

[0042] In the structure constituting the back surface protection substrate for the solar cell module of the present invention, the A layer, the B layer, and the A 'layer are laminated in this order, and the A layer and the A' layer are stacked. It is preferable that the longitudinal elastic modulus is more than 10 times the longitudinal elastic modulus of the B layer. Longitudinal elastic modulus of layer A and layer A 'When the longitudinal elastic modulus of layer B is 10 times or more, the structure constituting the back protective substrate for solar cell module of the present invention has high rigidity and light weight (specific Weight per area) is also preferable. The longitudinal elastic modulus of the A layer and the A ′ layer is more preferably 15 to LOO times the longitudinal elastic modulus of the B layer, and particularly preferably 20 to L 00 times the longitudinal elastic coefficient of the B layer. .

[0043] (Bending rigidity)

The structure constituting the back surface protection substrate for the solar cell module of the present invention has a bending rigidity of 0.5 X 10 ⁶ to 10 X 10 ⁷ kgf'mm ² per 1000 mm width when the thickness is 3 mm, for example. It is preferable. When the bending rigidity is in the above range, it is effective in suppressing warpage and deflection of the back surface protective substrate for solar cell module, which is preferable.

[0044] The bending rigidity per width of 1000 mm when the thickness of the structure is 3 mm is preferably 1.010 ⁶ to 10 10 ⁶ 1¾ 111111 ² , more preferably 1.5 X 10 ⁶ to 10 X 10 ^6. kgf 'mm ²

On the other hand, when the thickness of the structure is 8 mm, the bending stiffness per 1000 mm width is usually 2. OX 10 ⁶ to 10 X 10 ⁸ kgf'mm ² , preferably 3. OX 10 ⁶ to 10 X 10 ⁷ kgf 'mm ² , more preferably 5. OX 10 ⁶ to 10 X 10 ⁷ kgf' mm ² .

[0045] The bending stiffness of the structure can be predicted by the following equation when the A layer and the A 'layer are the same layer, and the shape of the structure and the lamination thickness constituting force.

[0046] Flexural rigidity EI = b (Ea (h ³ -c ³ ) + Eb · c ³ ) / 12 (kgf · mm ² )

Ea: Longitudinal elastic modulus of layer A (kgf Zmm ² )

Eb: Longitudinal elastic modulus of layer B (kgf Zmm ² )

h: Total structure thickness (mm)

c: B layer thickness only (mm)

b: Structure width (mm)

[0047] However, the bending stiffness of the actual structure is affected by the adhesive strength between the A layer, the A 'layer, and the B layer. Therefore, improving the adhesion between the A layer and the A ′ layer and the B layer has high practical value.

[0048] The actual measurement value of the bending stiffness can be calculated as follows: Measurement force of deflection amount in cantilever support of substrate.

Flexural rigidity ^{EI = PL 4/8 S (} kgf -mm 2)

P: Uniform load (kgf Zmm)

L: Length of beam (mm)

δ: Maximum deflection (mm)

[0049] (weight per area)

The structure constituting the back surface protection substrate for a solar cell module of the present invention has a weight per area of 0.5 to: LOkg Zm ² . If the weight per area is in the above range, This is preferable because it is effective in suppressing the deflection of the back surface protection substrate for joule. In addition, since the weight per area is 10 kg / m ² or less, it can contribute to weight reduction of the back surface protection substrate for the solar cell module and further to the light weight of the solar cell module, and thus has high practical value.

[0050] the weight per unit area of the structure is preferably 0. 5~7kg / m ^2, more preferably 0. 5 ~5kgZ m C, Mel.

[0051] The weight per area of the structure can be calculated by measuring the weight of the structure.

[0052] (Dielectric breakdown voltage)

The structure constituting the back protective substrate for a solar cell module of the present invention preferably has a dielectric breakdown voltage of 10 kV or more. When the dielectric breakdown voltage is in the above range, it is easy to maintain electrical insulation between the solar battery cell and Z or its wiring, etc., and the outside in a solar battery module using such a back surface protection substrate. This is preferable because normal and stable operation of the solar cell module can be secured.

[0053] The dielectric breakdown voltage of the structure is preferably 15 to 50 kV, more preferably 20 to 40 kV.

[0054] The breakdown voltage of the structure can be measured by a known breakdown voltage measuring device.

[0055] (Prepreda (Preferred ヽ A layer and A 'layer))

In the back surface protective substrate for a solar cell module of the present invention, at least one of the A layer and the A ′ layer contains a thermoplastic resin and a reinforcing fiber, and the volume content of the reinforcing fiber is 30% to 85%. Preferred to be a composite material layer, which is%. Hereinafter, such a composite material layer is also referred to as a pre-preder in this specification. The pre-preda is preferred that the reinforcing fiber has continuous long fiber strength in the direction.

[0056] Other than the prepreg, a resin film having an excellent longitudinal elastic modulus, particularly a stretched resin film, can be preferably used for the A layer and the Z or A 'layer. A film obtained by stretching a polyimide film is particularly preferable because it has a high longitudinal elastic modulus.

[0057] (Thermoplastic resin)

Pre-containing thermoplastic rosin and reinforcing fibers preferably used in the present invention Examples of the thermoplastic resin used in the preda include polypropylene, polystyrene, polyethylene, AS resin, ABS resin, ASA resin (polyacrylonitrile / polystyrene / polyacrylic acid ester), polymethylmethacrylate, nylon, Forces that can include polyacetal, polycarbonate, polyethylene terephthalate, polyphenylene oxide, fluorine resin, polyphenylene sulfide, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyimide, polyarylate, etc. These are not limited. Among these, propylene-based (co) polymers such as polypropylene are preferable because they are excellent in heat resistance and recyclability and can be obtained at a relatively low cost. One type of these thermoplastic resins may be used alone, or two or more types may be used in combination.

[0058] The propylene-based (co) polymer preferably used as the thermoplastic resin is not particularly limited as long as it contains propylene as the (co) polymerization component. From the viewpoint of mechanical strength and the like, a crystalline polypropylene-based resin is preferable. Here, “crystallinity” means that the crystallinity is 30% or more. The degree of crystallinity can be obtained by a conventional wide-angle X-ray diffraction.

[0059] The crystalline polypropylene-based resin is not particularly limited as long as it satisfies the above-mentioned "crystallinity" condition and has a structural unit derived from propylene force. For example, a propylene homopolymer or a copolymer of 2 to 20 carbon atoms other than propylene and at least one propylene (X-olefin can be mentioned. Here, the number of carbon atoms other than propylene is 2 Α-olefins of ˜20 include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl 1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1 -Otadecene, 1 eicosene, etc., but ethylene or α-olefin with carbon number power of ~ 10 is preferred, and these olefins may be used alone or in combination of two or more. These α-olefins may form a random copolymer with propylene or a block copolymer.

[0060] These structural units derived from α-olefin may be contained in polypropylene in a proportion of usually 20 mol% or less, preferably 15 mol% or less. Also good. For example, polypropylene homopolymer, pro propylene Z ethylene block copolymer an ethylene content of 20 to 70 weight ^_0/0, propylene Z ethylene random copolymer ethylene content from 0.5 to 12 weight ^_0/0, the ethylene content 0.5 to 12 weight ^_0/0 α Orefuin content such as butene 1 it can be preferably used propylene Zeta ethylene Zeta alpha-Orefuin terpolymers of 0.5 to 20 weight ^_0/0.

[0061] The crystalline polypropylene-based resin has a melt flow rate (MFR) measured at 230 ° C and a load of 2.16 kgf in accordance with ASTM D 1238 of 0.001 to 500 gZlO, preferably 0.01. It is desirable to be in the range of ~ 50g / 10min.

[0062] The melting point of the crystalline polypropylene-based resin observed with a differential scanning calorimeter is usually 110 ° C or higher, preferably 120 to 165, more preferably 110 to 150 ° C.

[0063] The crystalline polypropylene-based resin can use either a isotactic structure or a syndiotactic structure, but the isotactic structure is preferred from the viewpoint of heat resistance. Further, if necessary, a plurality of crystalline polypropylene-based resins can be used in combination. For example, two or more kinds of components having different melting points and rigidity can be used.

[0064] In addition, as the crystalline polypropylene-based resin, homopolypropylene having excellent heat resistance (usually known is a copolymer having a copolymer component other than propylene of 3 mol% or less is preferable), which has a good balance between heat resistance and flexibility. Excellent block polypropylene (usually known to have 3-30% by weight of normal decane-eluting rubber component), and random polypropylene with excellent balance of flexibility and transparency (usually measured by DSC) A known peak having a melting peak of 100 ° C. or higher, preferably in the range of 110 ° C. to 150 ° C.) may be selected or used in combination so as to obtain desired physical properties. It is possible and preferred.

[0065] Such a crystalline polypropylene-based resin is, for example, a solid catalyst component containing magnesium, titanium, halogen, and an electron donor as essential components, an organoaluminum compound, and a Ziegler catalyst system having an electron donor power, or a meta port. The polymer can be produced by polymerizing propylene or copolymerizing propylene and other α-olefins in a meta-cene catalyst system using a synthetic compound as one component of the catalyst.

[0066] (Reinforcing fiber) Examples of the reinforcing fiber used in the above pre-predder include glass fiber, carbon fiber, boron fiber, metal fiber, ceramic fiber (such as carbon carbide fiber), polyester fiber, salt bully acrylonitrile copolymer fiber, poly Examples include, but are not limited to, bull alcohol fiber and aramid fiber. Among these, glass fibers and carbon fibers are particularly preferable because a pre-preda produced using them has excellent strength and dimensional stability. Such reinforcing fibers may be used alone or in combination of two or more. Glass fibers are usually subjected to various surface treatments to improve adhesion to resins. The surface treatment is preferably performed by combining a coupling agent and a bundling agent described later.

[0067] (Glass fiber)

In the present invention, the glass fiber that is preferably used is not particularly limited, and a glass fiber that is usually used for a glass fiber reinforcing material can be appropriately used. Examples of preferred glass fibers include E glass, D glass, S glass, NE glass, and the like, but are not limited thereto. These glass fibers are appropriately selected depending on the intended use and performance of the molded product, and one kind may be used alone, or two or more kinds may be used in combination. More preferred fibers are, by weight, SiO: 50-60%, B 2 O: 15-30%

2 2 3

, Al 2 O: Glass fibers containing 8 to 20% can be mentioned. The glass fiber is

twenty three

May contain other components such as TiO, Li 0, Na 0, K 0, CaO.

2 2 2 2

About 10% (in the case of CaO, about 0-15%) can be contained.

[0068] (Carbon fiber)

The carbon fiber preferably used in the present invention is a concept including both carbon fiber and graphite fiber. This carbon fiber can be obtained by carbonizing a fibrous material such as polyacrylo-tolyl, pitch, etc., which is usually called “precursor”, or by heating to a graphite temperature. Elongation 1. Carbon fiber with high strength and high elongation of 7% or more is preferably used. In addition, a carbon fiber whose surface is introduced with a functional group such as a hydroxyl group or a carboxylic acid group by electrolytic oxidation or ozone oxidation can be suitably used.

[0069] These carbon fibers are also commercially available, and there are no particular limitations on the brand, but examples For example, Toray Power (registered trademark) manufactured by Toray Industries, Inc. can be preferably used.

[0070] (Coupling agent)

In the back surface protection substrate for a solar cell module of the present invention, it is preferable that the back surface protection substrate is treated with the reinforcing fiber strength coupling agent. As an example of the usage form of the coupling agent, first, a preferable coupling agent when the reinforcing fiber is glass fiber will be described.

[0071] As the coupling agent in the case of glass fiber, it is desirable to select an optimum coupling agent according to the resin to be combined. Specific examples will be given below. If the thermoplastic resin used in combination in the pre-preda is nylon resin, it is preferable to use y-aminopropyl-trimethoxysilane, N- | 8- (aminoethyl) -γ-aminopropyl monotrimethoxysilane, or the like. In the case of polycarbonate resin, it is preferable to use γ-aminopropyl monotrimethoxysilane, Ν—8- (aminoethyl) -γ-aminopropyl monotrimethoxysilane, and the like. If polyethylene terephthalate or polybutylene terephthalate is used, j8 — (3,4-epoxycyclohexyl) ethyl monotrimethoxysilane, γ-glycidoxypropyl methoxytrimethoxysilane, γ-aminopropyl monotrimethoxysilane, etc. are used. It is preferable to do this. In the case of polyethylene or polypropylene, it is preferable to use vinyltrimethoxysilane, vinyltris-1- (2-methoxyethoxy) silane, γ-methacryloxymonopropyltrimethoxysilane, or the like. The coupling agents described above can naturally be used as long as they are polyphenylene oxide, polyphenylene sulfide, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyimide, polyarylate, and fluorocarbon resin. In addition, Ν- (β-aminoethyl) -y-aminopropylmethyldimethoxysilane, γ-clopropylpropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, ρ-aminophenoltriethoxysilane, etc. should be used. Is also preferable.

[0072] When a fiber other than glass fiber is used as a reinforcing fiber, ammine-curable epoxy resin is often used as a coupling agent. Specific examples thereof include bisphenol-epoxychlorohydrin resin and epoxy novolac resin. And alicyclic epoxy resin, aliphatic epoxy resin, glycidyl ester type resin, and the like. However, since thermoplastic resin generally has a high melting temperature, ordinary coupling agents are thermally decomposed. In some cases, it is not used. Preferable method of applying coupling agent to fiber surface

This will be described below. As one method, when the fiber is melted and the monofilament is pulled out, a solution obtained by adding a surfactant to the sizing agent and coupling agent to form an aqueous solution is sprayed on the monofilament, and then the temperature is about 100 ° C. Dry and process. As another method, the fiber from which the bundling agent has been removed is completely impregnated with a solution obtained by dissolving 0.1 to 3% by weight of a sizing agent and a coupling agent by means such as dipping or spray coating. The fiber containing the coupling agent solution is dried at 60 to 120 ° C. to allow the coupling agent to react with the fiber surface. The drying time is sufficient for the solvent to evaporate, and is about 15 to 20 minutes. Solvents that dissolve the coupling agent include water adjusted to pH 2.0 to 12.0 depending on the surface treatment agent used, and organic solvents such as ethanol, toluene acetone, and xylene alone. Sometimes used in combination.

[0073] (Alignment of reinforcing fibers)

In the back surface protection substrate for a solar cell module of the present invention, it is preferable that at least a part of the reinforcing fibers are converged and arranged in one direction. By arranging the reinforcing fibers in one direction, the elastic modulus in the fiber direction results in the bow I being efficiently cut out to the maximum elastic modulus.

[0074] Regarding the method of converging a plurality of reinforcing fibers and arranging them in one direction, for example, the forces described in Japanese Patent Publication No. 04-042168, Japanese Patent Application Laid-Open No. 7-178859, etc. It is not limited to. In the present invention, it is particularly preferable that the reinforcing fibers are converged and arranged by the following method.

[0075] (Preparer manufacturing method)

It is one of the particularly preferred methods for producing a pre-preda in the present invention that a thermoplastic fiber is impregnated into a reinforcing fiber aligned in one direction to form a pre-preda. The most common method is as follows. One is a method in which if the resin is soluble in a solvent, the resin is solution-impregnated and impregnated into a reinforcing fiber, and then the solvent is removed while defoaming to obtain a prepreg.

[0076] The other is a method in which rosin is heated and melted and impregnated into a reinforcing fiber, defoamed and cooled to prepare a pre-preda. As a method for producing a pre-preda, for example, Japanese Patent Publication No. 04-042168 Can be mentioned. By this method, in the case of glass fiber, for example, the surface of a monofilament having a thickness of 13 μm is treated with γ-methacryloxymonopropyltrimethoxysilane, and 1800 pieces thereof are converged to form an untwisted yarn. It is possible to produce a pre-preda by aligning in one direction while pulling with uniform tension, entanglement of the resin with the yarn, and impregnating the resin with a heat roll while impregnating the yarn. The prepredder produced in this way has excellent adhesion between the fiber and the thermoplastic resin, the fiber content can be varied from 30 to 90% by volume, and the thickness can be varied from 0.1 to 1. Omm. Can be manufactured.

[0077] (content ratio)

In the present invention, the reinforcing fiber content of the pre-preda preferably used in the present invention is preferably 30% by volume to 85% by volume. If the reinforcing fiber content is 30% by volume or more, sufficient strength can be secured, and if the reinforcing fiber content is 85% by volume or less, a sufficient amount of resin exists for the reinforcing fiber, and the reinforcing fiber and the resin are filled. It is possible to suppress a decrease in strength due to a decrease in adhesion. The reinforcing fiber content is more preferably 35 to 80% by volume, and even more preferably 40 to 75% by volume.

[0078] The prepredder preferably used in the present invention contains thermoplastic rosin and reinforcing fibers, but may contain other components. Specific examples include, in addition to the coupling agents and sizing agents described above, various types of resins other than thermoplastic resins and Z or rubber, plasticizers, fillers, pigments, dyes, UV absorbers, Antioxidants, heat stabilizers, antistatic agents, antibacterial agents, antifungal agents, flame retardants, foaming agents, cross-linking agents, cross-linking aids, dispersants, etc. Can be contained.

[0079] (Resin foam (preferred layer B))

In the back surface protective substrate for a solar cell module of the present invention, the B layer is preferably a layer that also has a resin foaming power. If layer B is a layer that also has a resin foam strength, it is possible to reduce the weight of the back protection substrate for the solar cell module and, as a result, to reduce the weight of the solar cell module, which is also effective in preventing deflection. There is an advantage of being.

[0080] For the resin constituting the resin foam, any thermoplastic resin or thermosetting resin that is not particularly limited can be used. From the viewpoint of ease of molding, ease of recycling, etc. Heat Plastic resin is preferred. Although there is no restriction | limiting in particular in the thermoplastic resin which can be used for a resin foam, It is preferable to use the thermoplastic resin which can be used for a prepreader. These resin foams constituting the resin foam may be used alone or in combination of two or more.

[0081] Specific examples of the resin foam preferably used in the present invention include a propylene-based (co) polymer foam such as polypropylene foam, a polyethylene foam, a polystyrene foam or a polypropylene foam as an outer layer. Forces including, but not limited to, polystyrene foam. Of these, propylene-based (co) polymer foams are particularly preferred from the viewpoints of cost, strength, heat resistance, and the like.

[0082] The propylene-based (co) polymer preferably used as the thermoplastic resin is not particularly limited as long as it contains propylene as the (co) polymerization component. From the viewpoint of mechanical strength and the like, a crystalline polypropylene-based resin is preferable. The details of the crystalline polypropylene-based resin, and the details of its preferred form, have already been described in detail in the description of the thermoplastic resin that can be used for the pre-preparation.

[0083] In terms of easiness of heat welding, high rigidity and prevention of bending due thereto, ease of disposal of industrial waste, etc., the above-mentioned laminate is used for layer B (waxed foam). A composite structure composed of thermoplastic resin is preferred as the resin used for the resin and the A layer and the A 'layer (preprega). The A layer and the A' layer and the B layer are the same or A composite structure composed of substantially the same thermoplastic resin (for example, a composite structure composed of both propylene-based (co) polymers) is more preferable.

[0084] Here, "substantially the same" means a relationship in which a certain amount of mixing phenomenon occurs between the interfaces when both the resins are thermally bonded, and at least the interface before bonding disappears. Say that. Such a phenomenon occurs if both of the cocoons are compatible with each other at the time of melting.

[0085] The resin foam may be a closed cell or an open cell force. The strength is improved by using closed cells. The force with which the expansion ratio is usually 100 times or less is used. The magnification is selected according to the balance between weight reduction and moldability, and preferably 2 to 50 times. The cocoa foam may be a crosslinked product or a non-crosslinked product. Furthermore, the expansion ratio of the resin foam present near the surface of the surface is lower than the expansion ratio of the resin foam close to the center layer. Therefore, the present invention can be preferably applied.

[0086] There are no particular limitations on the method for producing the resin foam, and a conventionally known chemical foaming agent can be appropriately used. For example, azodicarbonamide (ADCA), N, N, monodinitrosopentamethylenetetramine, 4, 4'-oxybis (benzenesulfolhydrazide), diphenylsulfone-3,3, -disulfolhydrazide, p- Organic pyrolytic foaming agents such as toluenesulfol semicarbazide and trihydrazinotriazine, and inorganic pyrolytic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, and ammonium carbonate. Although it can use suitably, it is not limited to these. Physical foaming agents can also be used as appropriate, for example, vapors of low-boiling organic solvents such as methanol, ethanol, propane, butane, pentane; dichloromethane, chloroform, carbon tetrachloride, chlorofluorocarbon, trifluoride. Examples include, but are not limited to, vapors of halogen-based inert solvents such as nitrogen fluorides; inert gases such as carbon dioxide, nitrogen, argon, helium, neon, and astatine. Among these, a method using an inert gas is particularly preferable. Foaming with an inert gas is preferable from the viewpoint of safety during production and the environment, and there is no possibility of secondary foaming due to heating when using a foam by chemical foaming. Secondary foaming has the risk of causing substrate dimensional changes and appearance problems.

[0087] The resin foam can appropriately contain a resin constituting the resin foam and various additives other than the foaming agent. For example, crosslinking agents, crosslinking aids, plasticizers, fillers, pigments, dyes, UV absorbers, antioxidants, heat stabilizers, antistatic agents, antibacterial agents, antifungal agents, flame retardants, dispersants, etc. One or two or more additives selected from the above can be contained as appropriate.

[0088] (Structure and production method of laminate)

There is no particular limitation on the method for joining the pre-preda that is preferably used as the A layer or the A ′ layer and the resin foam that is preferably used as the B layer. it can. In the case of adhesive application, a method of applying an adhesive in advance and adhering, a method of applying an application-type hot-melt adhesive and drying it, and then sandwiching it with a heating roll or a hot press, or a film type For example, a hot-melt adhesive may be sandwiched between a hot roll or a hot press and bonded. Above all, heat fusion Adhesion is a preferred joining method because it does not require a special adhesive resin, can be joined in a relatively short time, and has a sufficiently high adhesive strength.

[0089] An example of a method of joining the pre-preda and the resin foam by thermal fusion is shown below. For example, the laminated prepredder is heated at the same time to the melting temperature or higher and the resin foam to the melting temperature at the same time. Pressurize at a pressure of ² or less to cool and integrally laminate to make a laminate. At this time, it is necessary to deaerate the air existing between the pre-predator layers of the pre-predator laminate. Usually, deaeration is performed by heating above the melting point of the resin constituting the pre-predder and pressurizing at a pressure of 3 kgfZcm ² or less. If the pressure is within this range, the resin foam is not crushed, so this deaeration can be performed in the step of integrating with the resin foam. As a matter of course, there is no problem even if a laminate is used after degassing and cooling. The heating of the prepreg and the foam can be carried out in a state where the prepreg and the resin foam are not in contact with each other, or in a state where the prepreg is placed on the resin foam and the two are in contact with each other. It can also be heated. When the foaming ratio of the resin foam is high, the foam is easily melted by heat, so that the melted pre-preda can be easily melted and integrated with the heat stored by the heat. It is desirable to heat separately by changing the heating conditions without contacting the oil foam. On the other hand, when the expansion ratio is low, heat does not easily transfer to the resin foam, so the molten prepredder can store heat, and the heat can not melt the surface of the resin foam. It is desirable to take a method in which the surface of the resin foam is heated while simultaneously heating the resin foam while bringing the resin foam into contact with each other.

[0090] Since the integral of the pre-preda and the resin foam is usually performed while the pre-preda is in a molten state, the step force for heating is changed to a step for performing the integral cohesion in a short time. Ingenuity is desired. As an example of such an apparatus, in a press in which a pre-predator and a resin foam are integrated, a pre-predder capable of entering and exiting the press and a resin foam are clamped and supported, and in the press A facility equipped with a pre-preda that can enter and exit and a hot plate that heats the resin foam. The procedure for forming a laminate using this equipment is to pull the clamp out of the press board surface, attach the pre-preda and foam, insert the clamp device into the press board surface, and then put the hot plate into the press board surface. Heat pre-preda and resin foam Then, after the heating is completed, the hot plate is pulled out of the press platen surface, and the press is tightened to melt and fuse the pre-preda and the foam in contact. At this time, the clamp must be provided with a mechanism for releasing the material and retreating from the press panel surface at the same time as it touches the press panel surface. Similar to the integration of the foam and the pre-predder, the surface material and the pre-predder can be integrated while the pre-predder is in a molten state.

[0091] (Configuration of back surface protection substrate for solar cell module)

The back surface protection substrate for a solar cell module of the present invention only needs to have at least three layers of A layer, B layer and A, layer. From the viewpoint of imparting many functions to the structure, A It is preferable to have a layer other than the layer, the B layer and the A ′ layer. If the layers other than the A layer, B layer and A 'layer are classified for the purpose, a hard coat layer, an adhesive layer, an antireflection layer, a gas barrier layer, an antifouling layer, etc. are provided for protecting the front or back surface. be able to. If classified by material, a layer made of UV-curable resin, a layer made of thermosetting resin, a layer made of polyolefin resin, a layer made of carboxylic acid-modified polyolefin resin, a layer made of fluorine-containing resin, etc. Can be provided.

[0092] A preferred layer configuration is appropriately selected depending on the relationship between the three layers of the A layer, the B layer, and the A 'layer and the other layers without any particular limitation. That is, the layers other than the A layer, the B layer, and the A ′ layer may be provided between the A layer and the B layer, or the B layer and the A ′ layer, or may be provided on the outermost layer of the back surface protection substrate for the solar cell module. It may be provided, or may be provided at other locations. There is no particular limitation on the number of layers other than the A layer, the B layer, and the A ′ layer, and any number of layers may be provided.

[0093] The back surface protection substrate for a solar cell module of the present invention further includes a layer (C layer) including a material having a deformation amount force or less in a section from 30 ° C to 100 ° C at the time of TMA measurement. May be. When the amount of deformation in the section from 30 ° C to 100 ° C during TMA measurement is 4% or less, the effect of the present invention with high heat resistance can be sufficiently exerted. The deformation rate is further preferably 3% or less, more preferably 2% or less.

[0094] When the back surface protective substrate for a solar cell module has a C layer, the A layer, the B layer, the A 'layer, and the C layer are preferably laminated in this order. Further, the longitudinal elastic modulus E (k

C

and gfZmm ^2), the linear expansion coefficient of the C layer ^{CTE (10- 6 Z ° C)} , the thickness of the C layer h (mm) The C layer of the film coefficients Fc (10- ⁶ kgfZmm ° C) is preferred to satisfy the relation given by the following formula (B), derived according to the following formula (A) and a.

Formula (A): F = E X CTE X h

c c c c

c

[0095] Film coefficient Fc of the C ^{layer, 1000 (10 "6 kgf /} mm ° C) ≤F ≤ 10000 (10- 6 kgf

c

Zmm ° C) 2000 (10— ⁶ kgf Zmm ° C) ≤F ≤5000 (10 " ⁶ kgf /

c

More preferably, it is mm ° C). By satisfying the above relationship, when the solar cell module is configured using the back surface protection substrate for solar cell module of the present invention, the space between the back surface protection substrate for solar cell module and the surface protection sheet for solar cell module described later is used. The effect which prevents the curvature considered to originate in the difference (thermal stress) of the linear expansion coefficient of this is acquired.

[0096] The material included in the C layer preferably has a longitudinal elastic modulus of lOOkgZmm ² or more. In addition, from the viewpoint of heat resistance when heated when assembling the module, it is preferable that the deformation force is not more than 30 ° C to 100 ° C during TMA measurement.

[0097] Materials included in the C layer include polyolefins, polystyrenes, polycarbonates, polyesters, polyamides, polyamideimides, polyphenylene ethers, polyacetals, polyarylates, polyphenylene sulfides, polyethers- Examples include tolyl, liquid crystal polymers, polyether ketones, thermoplastic polyimides and the like, and specifically, polymer alloys having two or more of these types of propylene-based (co) polymers, which are preferred. Further, the propylene (co) polymer has a 97 mole ^_0/0 or more constitutional units derived from propylene, and preferably has a Aisotakuchikku structure.

[0098] The C layer is preferably substantially unstretched. When the C layer is substantially stretched, the longitudinal elastic modulus increases due to molecular orientation, while the linear expansion coefficient becomes extremely small. Therefore, their product becomes smaller than that of an unstretched product. In other words, it is necessary to make the film thicker so that the film coefficient of the C layer as a whole is within the above range.

Since it is difficult to adjust the film coefficient F, it is difficult to obtain a 1S stretched product.

c

It is.

When forming the C layer on the A ′ layer, it is possible to adhere the C layer to the A ′ layer using a resin or an adhesive. Prefer to use fat Good. Examples of the resin or adhesive that can be used for bonding the C layer and the A ′ layer include a hot melt adhesive, a reactive adhesive, and a solution adhesive.

[0099] The hot-melt adhesive is an adhesive that is melted between adherends using a thermoplastic resin film or a nonwoven fabric. Such hot-melt adhesives include ethylene butyl acetate copolymer (EVA), ethylene butyl glycidyl methacrylate copolymer terpolymer, ethylene vinyl acetate partial acid mono organic acid graft ethylene-vinyl acetate copolymer and modified榭脂ethylene vinyl acetate copolymer of quaternary, etc. copolymers, ethylene _'a Orefuin copolymer, propylene' a Orefuin copolymer, propylene-ethylene _alpha -.. Orefuin Preferred are olefin-based copolymers such as copolymers, polybutyrral, carboxyl-containing polyolefins such as maleic anhydride grafted polyethylene, and polyester-modified resins such as ethylene terephthalate mono-modified alkylene ether terephthalate block copolymers. Used for.

More preferably, an ethylene copolymer such as an ethylene acetate butyl copolymer or an ethylene _α- olefin copolymer is blended with an initiator such as an organic peroxide to enable thermal crosslinking. . Specifically, “Solar Enoku” (trade name, manufactured by Mitsui Engineering & Technology Co., Ltd.), which is an ethylene vinyl acetate copolymer film with a crosslinking agent added, can be suitably used.

[0100] The reactive adhesive includes a two-component type using a curing agent and a one-component type due to external factors such as heat 'moisture' ultraviolet rays. Examples of the reactive adhesive include acrylic, urethane, epoxy, and silicone monomers. Specifically, “Takelac Α-310” (trade name, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) as the main agent and “Takenate Α—3” (trade name, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) as the curing agent Urethane-based adhesives using are preferably used.

[0101] Examples of the solution-based adhesive include a polymer such as urethane, chloroprene rubber, and styrene-butadiene rubber, or a polymer obtained by dissolving a polymer in an organic solvent. Specifically, “Unistor®-401” (trade name, manufactured by Mitsui Chemicals, Inc.) mainly composed of maleated polyolefin is used.

The above-mentioned adhesive, when using a curable adhesive, has the effect of correcting warpage compared to the thermoplastic type. large.

[0102] Among the above adhesives, from the viewpoint of workability, hot melt type adhesives are preferred. From the viewpoint of module warpage correction, those that are cured and cross-linked are more preferable. The C layer is preferably attached to the A ′ layer by a layer comprising a crosslinkable ethylene acetate butyl copolymer. Specifically, it is preferable to bond the C layer, the A layer, and the above-described “solar energy”.

[0103] The C layer may be subjected to a surface treatment. Examples of the surface treatment include corona discharge, UV ozone treatment, flame treatment, sand blast treatment, and primer treatment. For example, corona discharge, UV ozone treatment, flame treatment, etc. can improve the surface roughness of the C layer and generate functional groups on the surface of the C layer, and surface treatment on the C layer by sandblasting etc. Since the surface roughness can be improved by applying, the adhesive strength can be increased by these treatments.

It is also possible to provide the C layer by thermally fusing it to the A ′ layer in advance when manufacturing the back surface protective substrate for a solar cell module of the present invention. However, in this case, the front force for assembling the module due to the thermal contraction of the C layer may easily cause reverse warping. Therefore, from this point of view, it is preferable to provide an adhesive layer and allow the entire assembly process to pass through.

[0104] (Solar cell module)

The back surface protection substrate for a solar cell module of the present invention has excellent mechanical properties suitable for a protection substrate for a solar cell module, and can particularly effectively suppress bending and warping. Moreover, it can be provided with excellent dimensional stability, lightness, moisture resistance, scratch resistance, dielectric breakdown strength, etc. as required. Therefore, the solar cell module having the back surface protective substrate for the solar cell module of the present invention has excellent characteristics, and is one of the particularly preferred embodiments of the present invention.

[0105] (Usage method of back surface protection substrate for solar cell module)

A typical solar cell module has a structure in which solar cells made of polycrystalline silicon or the like are sandwiched and laminated with a sealing resin layer that has the same strength as ethylene vinyl acetate (EVA), and both sides are covered with protective sheets. It becomes. Ie a typical solar cell The module is composed of a solar cell module protective sheet (surface protective sheet) Z sealing material layer Z solar cell Z sealing material layer Z solar cell module protective sheet (back surface protection substrate) ( Even if it does not correspond to the above typical configuration, if the back surface protection substrate for the solar cell module of the present invention protects the solar cells in some form such as the back surface side, Needless to say, it is used as a backside protection board).

[0106] The back surface protection substrate for a solar cell module of the present invention can be preferably used as a back surface protection substrate for protecting the solar cell of the solar cell module. The backside protection board is particularly necessary for large modules with a side length exceeding lm, and there is a high risk of external impact and there is a strong demand for light weight. The back surface protective substrate for solar cell module of the present invention can be particularly preferably used.

[0107] As described above, the solar cell module of the present invention includes the surface protection sheet (I) for the solar cell module, the sealing material layer (II), the solar battery cell (ΠΙ), and the sealing material layer (IV). It is preferable that the back surface protection substrate (V) for solar cell module of the present invention is laminated directly or indirectly in this order.

At this time, the back surface protection substrate (V) for the solar cell module of the present invention has a deformation amount of 4% or less and a longitudinal elastic modulus of 100 kg fZmm ² or more in the section from 30 ° C to 100 ° C at the time of TMA measurement as C layer. It is preferable that the A layer, the B layer, the A ′ layer, and the C layer are laminated in this order. The back surface protective substrate (V) for the solar cell module is preferably laminated so that the A layer is positioned on the sealing material layer (IV) side. That is, the A layer is laminated directly or indirectly with the encapsulant layer (IV).

[0108] Further, the thickness h (mm) of the surface protection sheet (I) for the solar cell module and the thickness h (mm) of the C layer are 0.5≤h / h≤2.0. It is preferable to satisfy the conditions. When the above h / h c C I C I satisfies the above-mentioned relationship, unlike the case where the thicknesses of the two are extremely different, it becomes easy to satisfy the requirements for the warp prevention effect. H Zh satisfies the condition of 0.7≤h / h≤l.5.

C I C I

It is more preferable that the condition of 0.8≤h / h≤l.2 is satisfied.

C I

[0109] Furthermore, the solar cell module of the present invention is guided according to the following formulas (1) and (2). It is preferable that the specific coefficient satisfies the relationship of the following formula (3).

Formula (1): F = E X CTE X h

Formula (2): F = E X CTE X h

c c c c

Formula (3): 0. 7≤F / F≤l. 3

C I

[0110] Specifically,

Wherein the longitudinal elastic coefficient of the solar cell module surface protective sheet ^{(I) (kgf / mm 2} ), before Symbol solar cell module surface protective sheet (I) linear expansion coefficient CTE, and (10- ⁶ Z ° C), Karel guide according thickness h (mm) from the following equation (1) of the solar cell module surface protective sheet (I), the film coefficient (10- ⁶ kgfZ mm ° C of the solar cell module surface protective sheet (I) )When,

C C

And the film coefficient derived from the thickness h (mm) of the C layer according to the following formula (2):

C

F (10- ⁶ kgfZmm ° C) and the ratio of (F ZF) preferably satisfies the relationship of the above equation (3).

C C I

If each of these elements satisfies the relationship of the above formula (3), it is possible to prevent the warp that occurs in the heating / cooling process of the module preparation process, which can contribute to the reduction of the defect rate.

[0111] The above relationship is not limited to the case where the back surface protection substrate for solar cell module of the present invention is used as the back surface protection substrate (V) for solar cell module. The effect can be obtained even when a protective substrate is used. That is, the surface protection sheet for solar cell module (1), encapsulant layer (Π), solar cell (II I), encapsulant layer (IV) And a solar cell module in which the back surface protective substrate (V) for a solar cell module having a laminated structure is laminated directly or indirectly in this order, the longitudinal elasticity of the surface protective sheet (I) for the solar cell module the coefficient E (kgfZmm ^2), before Symbol the solar cell module surface protection sheet for the linear expansion coefficient of the ^{(I) CTE (10- 6 Z} ° C), before Symbol thickness of the solar cell module surface protective sheet (I) ( mm) and the sun derived from the following formula (1) Film coefficient of surface protection sheet (I) for battery module F (10 " ⁶ kgf E (kgf / mm ² ) is the longitudinal elastic modulus of the layer (C layer) on the side opposite to the side in contact with the sealing material layer (IV) of the back surface protection substrate (V) for the solar cell module; Coefficient of linear expansion CT

C

E and (10- ⁶ Z ° C), derived according to the following equation from the thickness h (mm) of the C layer (2), the C

C C

C C I

By doing so, it is possible to prevent warping that occurs during the heating / cooling process of the module assembly process.

Formula (1): F = E X CTE X h

Formula (2): F = E X CTE X h

c c c c

Formula (3): 0. 7≤F / F≤l. 3

C I

[0112] Since the back surface protection substrate for solar cell modules of the present invention is excellent in bending rigidity, light weight, insulation protection characteristics, etc., the solar cell module having such a protection substrate is light and robust, and is used outdoors. It is expected to be suitable for use and have a long life.

[0113] (Surface protection sheet for solar cell module)

The surface protection sheet for a solar cell module used in the solar cell module which is a preferred embodiment of the present invention is not particularly limited. However, since the surface protection sheet is located on the outermost layer of the solar cell module, in order to ensure long-term reliability of the solar cell module in outdoor exposure, including weather resistance, water repellency, contamination resistance, and mechanical strength. It is preferable to have the following performance. Further, in order to effectively use sunlight, a highly transparent sheet having a small optical aperture is preferable. Examples of the material for the surface protection sheet for solar cell modules that are preferably used for the solar cell module include polycarbonate resin, polyester resin, fluorine resin, acrylic resin, cyclic olefin (co) polymer, etc. A glass substrate etc. are mentioned other than a film.

Particularly preferred as the resin film is a polyester resin, particularly polyethylene terephthalate resin, which is excellent in terms of transparency, strength, cost and the like.

In addition, fluorine resin having particularly good weather resistance is also preferably used. Specifically, tetrafluorinated ethylene ethylene copolymer (ETFE), polyfluorinated burr resin (PVF), polyvinylidene fluoride resin (PVDF), polytetrafluoroethylene rubber (TFE), tetra There are fluorinated ethylene 16-propylene copolymer (FEP) and polytrifluoride-ethylene resin (CTFE). Weatherability From this point of view, polyvinylidene fluoride resin is excellent. However, in terms of both weather resistance and mechanical strength, a tetrafluoroethylene-ethylene copolymer is excellent. In addition, it is desirable to perform corona treatment and plasma treatment on the surface protective sheet in order to improve adhesion with materials constituting other layers such as a sealing material layer. It is also possible to use a sheet that has been subjected to a stretching treatment to improve mechanical strength, such as a biaxially stretched polypropylene sheet. When glass is used as the surface protective sheet for a solar cell module, the total light transmittance of light having a wavelength of 350 to 1400 nm is preferably 80% or more, more preferably 90% or more. Generally, white glass with low absorption in the infrared region is used as the glass substrate to be covered. However, even with blue glass, if the thickness is 3 mm or less, the output characteristics of the solar cell module can be reduced. The impact is small. Further, in order to increase the mechanical strength of the glass substrate, a float plate glass without force heat treatment that can obtain tempered glass by heat treatment may be used. Further, in order to suppress reflection on the light receiving surface side of the glass substrate, antireflection coating may be applied.

[0114] (Encapsulant layer)

The solar cell module of the present invention usually has a sealing material layer disposed so as to sandwich solar cells. The material of the encapsulant layer is not particularly limited, but may be composed of a resin that is in close contact with the solar cell and melted and softened at a temperature when the solar cell and the front surface or back surface protective layer are laminated. preferable. The lamination temperature is usually below 150 ° C, preferably below 120 ° C. Examples of the resin preferably used for such a sealing material layer include ethylene vinyl acetate copolymer (EVA), ethylene butyl glycidyl methacrylate terpolymer, ethylene vinyl acetate partial oxide, organic acid graft tetra Ethylene vinyl acetate copolymer, ethylene vinyl acetate copolymer, ethylene 'α-olefin copolymer, propylene' α-olefin copolymer, propylene 'ethylene' Polyolefins such as a-olefin copolymers, polybutylbutyral, carboxyl group-containing polyolefins such as maleic anhydride-grafted polyethylene, and polyester-modified resins such as ethylene terephthalate mono-modified alkylene ether terephthalate block copolymers Such as, but not limited to.

[0115] Among these, ethylene vinyl acetate copolymer strength Its flexibility, transparency, heat resistance Isotropic preferably used. There is no particular limitation on the ethylene-butyl acetate copolymer used for the sealing material layer. For example, a conventionally known ethylene-vinyl acetate copolymer can be appropriately used. More preferably, an initiator such as an organic peroxide is added to enable thermal crosslinking. Specifically, “Solar Enoku” (trade name, manufactured by Mitsui Engineering & Technology Co., Ltd.), which is an ethylene vinyl acetate copolymer film with a crosslinking agent added, can be suitably used.

[0116] Among the above-mentioned various resins, the olefin-based copolymer can easily obtain a resin having excellent transparency and flexibility, and can be used as a sealing material without crosslinking. Therefore, it can be preferably used for the sealing material layer from the viewpoint of production cost and the like.

[0117] Both silicon and compound semiconductors described later have excellent characteristics as solar cell elements. It is known that they are easily damaged by external stress, impact, and the like. If a material having excellent flexibility is used for the solar cell encapsulant layer, the solar cell element is effectively damaged by absorbing stress, impact, etc. on the solar cell element. Furthermore, in the solar cell module which is a preferred embodiment of the present invention, it is desirable that the solar cell sealing material layer is directly joined to the solar cell.

[0118] Further, if the solar cell encapsulant has thermoplasticity, and even after the solar cell module is manufactured, the solar cells can be taken out relatively easily. Excellent recyclability.

[0119] (Solar cell)

The solar battery cell in the solar battery module which is a preferred embodiment of the present invention is not particularly limited as long as it can generate power using the photovoltaic effect of a semiconductor. For example, silicon (single crystal system, polycrystalline system, Amorphous solar cells, compound semiconductors (Group 3-5, Group 2-6, etc.), solar cells, wet solar cells, organic semiconductor solar cells, etc. can be used. Of these, polycrystalline silicon solar cells are preferred from the viewpoint of balance between power generation performance and cost.

[0120] (Power generation device)

The solar cell module which is one of the particularly preferred embodiments of the present invention is effectively prevented from warping, and is often excellent in mechanical strength, light weight, life and the like. For this reason A power generator using such a solar cell module is easy to impart excellent impact resistance, weight, life, etc., and has a high practical value.

[0121] The above power generator is installed on the roof of a house, used as a mobile power source for outdoor activities such as camping, and used as an auxiliary power source for automobile batteries. Is preferred.

[Example]

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is V, but is not limited to these examples.

[0122] In the above description and the examples and comparative examples described later, various physical properties of samples and the like were measured as follows.

[0123] 'Bending rigidity: The obtained back surface protection substrate for the solar cell module was cut into a width of 1000mm and a length of 1400mm, and the maximum deflection of the substrate as a cantilever beam fixedly supported for 400mm on one side in the length direction. Was measured. Next, the bending rigidity ΕΙ was calculated by the following formula. Flexural rigidity ^{EI = PL 4/8 S (} kgf -mm 2)

P: Uniform load (kgfZmm)

L: Length of beam (1000mm)

δ: Maximum deflection (mm)

[0124] 'Weight per area: The weight of the substrate having a width of 1000 mm and a length of 1400 mm was measured with a weigher and the weight per unit area was calculated.

[0125] 'Dielectric breakdown strength: The test piece obtained by cutting the back protection substrate for the solar cell module into 100 X 100mm was compliant with JIS C2110, and it was changed to the HAT-3100-100RHO type dielectric breakdown tester manufactured by Yamazaki Sangyo Co., Ltd. The voltage rise rate was 2 kVZs. The electrode used was a spherical type with an upper part of 20 mm in diameter and a lower part with a circular cross section of 25 mm in diameter.

[0126] Deflection: Measured by the method described above in addition to the above-described bending stiffness measurement method.

[0127] · Longitudinal elastic modulus: Each layer used for the back protection substrate for solar cell modules was tested using a tensile tester at a tensile speed of 10mmZmin and a chuck interval of 60mm to measure the initial elastic modulus (Young's modulus). The longitudinal elastic modulus was used. [0128] 'Warpage: The obtained back surface protection substrate for the solar cell module was cut to 250 x 250 mm, a simulation module was created with the configuration described later (Examples 4 to 9), and the four corners of the obtained simulation module were created. The amount of lifting was measured and the average was taken as warpage.

[0129] <Back side protection substrate for solar cell module>

[Example 1]

As A layer, the glass fiber-reinforced composite sheet L15 (Puredaron (registered trademark), Mitsui I匕学Co., thickness: 0. 25 mm, the longitudinal elastic modulus: 1600 kgf / mm ^2, the glass fiber content: 50 volume ^_0/0 , Weight per area: 300gZm ² ), PP layer 3 times foam sheet as B layer (trade name paror board, made by Mitsui Engineering Co., Ltd., longitudinal elastic modulus: 50kgfZmm ² , thickness 8mm, weight per area: 2. 9kgZm ² ), using the above-mentioned glass fiber reinforced composite sheet L15 for the A 'layer, these three layers are stacked and heat-sealed with a hot press molding machine at 220 ° C under a preheating time of 2 minutes, Further cooling was performed to obtain a back surface protection substrate for a solar cell module having a length of 1400 mm, a width of 1000 mm, and a thickness of 8.4 mm. The weight per unit area of the back surface protection substrate for the solar cell module was 3.5 kgZm ² , the light deflection was 75 mm, and the bending rigidity was 5.8 × 10 ⁶ kgf 'mm ² . The dielectric breakdown voltage was 35kV, which was a sufficient value as an insulation protection substrate for solar cells.

[0130] [Example 2]

As A and A 'layers, glass fiber reinforced composite sheet P30 (Predaron (registered trademark), manufactured by Mitsui Chemicals, Inc., thickness: 0.45 mm, longitudinal elastic modulus: 3300 kgf Zmm ² , glass fiber content: 50 volume%, area A back protective substrate for a solar cell module was prepared in the same manner as in Example 1 except that the weight per unit was 600 gZm ² ). The weight per unit area of the back surface protection substrate for solar cell modules was 4. lkgZm ² , the light deflection was 15mm, and the bending rigidity was very small, 3.4 × 10 ⁷ kgf 'mm ² . The dielectric breakdown voltage was 35kV, which was a sufficient value as an insulation protection substrate for solar cells.

[0131] [Example 3]

PP layer 4.5 times expanded sheet (trade name Cellplanlite, manufactured by Mitsui Engineering & Technology Co., Ltd., longitudinal elastic modulus: 25kgfZmm ² , thickness 19mm, weight per area: 4.2kgZm ² ) was used as layer B. Others produced the back surface protection substrate for solar cell modules similarly to Example 1. Obtained The weight per unit area of the back surface protection substrate for the solar cell module was 4.8 kgZm ² , the light deflection was 10 mm, the bending rigidity was very small, 6. OX 10 ⁷ kgf 'mm ² and excellent. The dielectric breakdown voltage was 39kV, which was a sufficient value as an insulation protection substrate for solar cells.

[0132] [Comparative Example 1]

A and A, as a layer, PP unstretched sheet (trade name Super Pure Ray, Idemitsu Interview - Tech Co., modulus of longitudinal elasticity: 216kgfZmm ^2, thickness 0. 2 mm, the weight per unit area: 200gZm ²⁾ other using Produced a back protective substrate for a solar cell module in the same manner as in Example 1. Although the weight per unit area of the obtained back surface protection substrate for solar cell modules was as light as 3.3 kg / m ² , the flexural rigidity was as large as 253 mm and 1.6 x 10 ⁶ kgf 'mm ² , Bending rigidity was insufficient as a back protective substrate for solar cell modules with a thickness of about 8 mm. On the other hand, the dielectric breakdown voltage was 33 kV, which was a sufficient value as an insulation protection substrate for solar cells.

[Comparative Example 2]

A and A, PP3 times foamed sheet as the layer (tradename Paro - Abodo, Mitsui I匕学Fuabu port Co., modulus of longitudinal elasticity: 50kgfZmm ^2, thickness 3 mm, weight per unit area: lkgZm ^2), and B layer glass fiber-reinforced composite sheet L15 Te (Puredaron (registered trademark), Mitsui I匕学Co., thickness 0. 25 mm, the modulus of longitudinal elasticity: 1600kgfZm ^2, glass fibers 50 volume ^_0/0) except that the example 1 It carried out like. The weight per unit area of the obtained back surface protection substrate for solar cell modules was 2.3 kg / m ² and the force was light. The deflection was large at 625 mm and the bending stiffness was low at 4.6 X 1 0 ⁵ kgf 'mm ² Bending rigidity as a back surface protection substrate for solar cell modules was insufficient.

[Comparative Example 3]

Glass fiber-reinforced composite sheet L15 (Puredaron (registered trademark), Mitsui I匕学Co., thickness 0 25 mm, longitudinal elastic modulus:. 1600kgfZmm ^2, glass fibers 50 volume ^_0/0) 40 Like the hot press forming mold machine After preheating at 220 ° C for 2 minutes, press molding was performed to obtain a back protective substrate for a solar cell module with a thickness of 8.6 mm. The obtained back surface protection substrate for the solar cell module has a large weight per unit area of 12 kgZm ² and heavy deflection of 298 mm. Bending rigidity as a back surface protection substrate for a rail was insufficient.

[0135] <Solar cell module>

[Example 4]

A back protective substrate for a solar cell module was obtained in the same manner as in Example 1 except that the thickness of layer B was 3 mm and the size was 250 × 250 mm. Next, on a glass plate with a thickness of 3 mm (this glass plate is just a support base and does not remain in the final configuration), a polycarbonate film (trade name Panlite, manufactured by Teijin Chemicals Ltd.) is used as a surface protection film. Made by the inventors using L-1225Z, thickness: 0.18 mm, 2 sheets of ethylene acetate vinyl copolymer film with a crosslinking agent added as a sealant (trade name Solar EVA SC-50B, Mitsui Chemicals) Manufactured by Fabuguchi Co., Ltd. (thickness: 600 m), back protection substrate for the above solar cell module, the same SC-50B as the sealing material as the adhesive layer, and the same polycarbonate film as the surface protection film as the C layer Were stacked in this order from the bottom, and lamination was carried out for 3 minutes under reduced pressure and 10 minutes under pressure using a double vacuum type vacuum laminator (trade name, manufactured by ENPC Co., Ltd.). The temperature setting of the unit was 124 ° C. In this way, a simulation module was obtained, in which a silicon cell, originally a photoelectric conversion element, was sandwiched between two encapsulants. This is a simple test, so it is not included because it is a simple test.After lamination, the simulated module is cut off from the glass plate, turned upside down and transferred to an air thermostat, and heat treated at 140 ° C for 40 minutes. (EVA bridging process), the wire net was passed over the air and allowed to cool on a cooling stand.

As shown in Table 1, the film coefficient ratio between the C layer and the surface protection sheet of the simulation module obtained was 1.00, and the warpage of the simulation module was 0. Omm.

[Example 5]

Cast polypropylene film made of homopolypropylene with isotactic structure as the C layer (produced by the inventors using the product name Prime Polypro F-107BV manufactured by Prime Polymer Co., Ltd., except that thickness: 0.2 mm was used) In the same manner as in Example 4, a simulation module was obtained.

As shown in Table 1, the film coefficient ratio between the C layer and the surface protection sheet of the simulation module obtained was 1.02, and the warpage of the simulation module was -0.5 mm. [Example 6]

Cast polypropylene film made of homopolypropylene with isotactic structure as C layer (produced by the inventors using Prime Polypro F-107BV, manufactured by Prime Polymer Co., Ltd., except that thickness: 0.1 mm was used) In the same manner as in Example 4, a simulation module was obtained.

As shown in Table 1, the film coefficient ratio between the C layer and the surface protection sheet of the obtained simulation module was 0.51, and the warpage of the simulation module was 1. Omm.

[Example 7]

Cast polypropylene film made of homopolypropylene with isotactic structure as layer C (produced by the inventors using Prime Polypropylene F-107BV, manufactured by Prime Polymer Co., Ltd., except that thickness: 0.3 mm was used) In the same manner as in Example 4, a simulation module was obtained.

As shown in Table 1, the film coefficient ratio between the C layer and the surface protection sheet of the simulation module obtained was 1.52, and the warpage of the simulation module was 1. Omm.

[Example 8]

Except for using a random polypropylene film (made by Prime Polymer Co., Ltd., trade name Prime Polypro F-327BV, thickness: 0.2 mm) containing ethylene as a copolymer component as layer C In the same manner as in Example 4, a simulation module was obtained.

As shown in Table 1, the film coefficient ratio between the C layer and the surface protection sheet of the obtained simulation module was 1.11, but the amount of deformation in the 30 ° C to 100 ° C interval during TMA measurement However, the warpage of the simulation module was 1.1 mm.

[0140] [Example 9]

A simulation module was obtained in the same manner as in Example 4 except that a polyethylene naphthalate film (manufactured by Teijin DuPont Films, trade name: Teonex Q51, thickness: 0.19 mm) was used as the C layer.

As shown in Table 1, the film coefficient ratio between the C layer and the surface protection sheet of the simulation module obtained was 0.40, and the warpage of the simulation module was 2.4 mm.

[0141] [Table 1]

Explanation of symbols

2

3 A 'layer

4 L: Length of beam 5 δ: Maximum deflection :!

Claims

The scope of the claims

[I] longitudinal elastic coefficient is 500KgfZmm ² or more LOOOOkgfZmm ² or less layers (A layers), modulus of longitudinal elasticity is less than LOkgfZmm ² more 500KgfZmm ² layer (B layer), and the modulus of longitudinal elasticity 500KgfZmm ² more LOOOOkgfZmm ² or less A back surface protection substrate for a solar cell module including a structure having at least three layers (の ′ layer), and the weight per area of the structure is 0.5 kg / m ² or more and 10 kg / m Protective substrate for solar cell module that is ² or less.

[2] The A layer, the B layer, and the A ′ layer are laminated in this order, and the longitudinal elastic modulus of the A layer and the A ′ layer is 10 times or more of the longitudinal elastic modulus of the B layer. The back surface protection substrate for solar cell modules described in 1.

[3] At least one of the A layer and the A ′ layer contains a thermoplastic resin and a reinforcing fiber.

And a composite material layer having a volume content of the reinforcing fibers of 30% to 85%.

The back surface protection substrate for solar cell modules according to claim 1 or 2.

[4] The back protective substrate for a solar cell module according to [3], wherein the B layer contains a thermoplastic resin substantially the same as the thermoplastic resin.

[5] The back protective substrate for a solar cell module according to claim 3 or 4, wherein the thermoplastic resin is a propylene-based (co) polymer.

[6] The back protective substrate for a solar cell module according to any one of claims 3 to 5, wherein the B layer contains a propylene-based (co) polymer.

[7] The back protective substrate for a solar cell module according to any one of claims 3 to 6, wherein the reinforcing fiber is a glass fiber or a carbon fiber.

[8] The back protective substrate for a solar cell module according to any one of claims 3 to 7, wherein the reinforcing fiber is treated with a coupling agent!

[9] The back surface protection substrate for a solar cell module according to any one of claims 3 to 8, wherein at least a part of the reinforcing fibers are converged and arranged in one direction.

[10] The back surface protective substrate for a solar cell module according to any one of claims 1 to 6, wherein the B layer is a layer having a foamed foam strength.

[II] The rear surface protective substrate for solar cell module according to any one of claims 1 to 10, A solar cell module.

[12] Surface protection sheet for solar cell module (I), encapsulant layer (II), solar cell (III), encapsulant layer (IV), and any one of claims 1 to 10 12. The solar cell module according to claim 11, wherein the back surface protection substrate (V) for solar cell module is laminated directly or indirectly in this order.

[13] The back surface protection substrate (V) for the solar cell module further includes a material having a deformation force in the section of 30 ° C to 100 ° C at the time of TMA measurement and a longitudinal elastic modulus of lOOkgf Zmm ² or more. A layer (C layer), and the A layer, B layer, A ′ layer, and C layer are laminated in this order, and the A layer is located on the sealing material layer (IV) side. Item 12. The solar cell module according to item 12.

[14] Vertical and modulus E (kgf / mm ^2), the linear expansion coefficient of the previous SL solar cell module surface protective sheet ^{(I) CTE (10- 6 Z} ° of the solar cell module surface protective sheet (I) C) and the thickness (mm) of the surface protection sheet (I) for the solar cell module described above, the film coefficient F (10 ") of the surface protection sheet (I) for the solar cell module derived from the following formula (1) ⁶ kgf / mm ° C)

C C

c

Satisfies beam coefficient F (10- ⁶ kgfZmm ° C) and the ratio of (F ZF) forces under formula the relationship (3), according to claim 1

C C I

14. A solar cell module according to 2 or 13.

Formula (1): F = E X CTE X h

Formula (2): F = E X CTE X h

c c c c

Formula (3): 0. 7≤F / F≤l. 3

C I

[15] A power generator having the solar cell module according to any one of claims 11 to 14.

[16] Surface protection sheet for solar cell module (I), encapsulant layer (II), solar cell (III), encapsulant layer (IV), and back surface protection substrate for solar cell module having a laminated structure (V) are stacked directly or indirectly in the order of force,

The longitudinal elastic modulus E (kgfZmm ² ) of the surface protection sheet (I) for the solar cell module, Serial photovoltaic linear expansion coefficient of the module surface protective sheet (I) CT ^ and (10- ⁶ / ° c), before Symbol following equation from the thickness h (mm) of the solar cell module surface protective sheet (I) ( Film coefficient F (10 " ⁶ kgf / mm ° C) of the surface protection sheet for solar cell module (I), guided according to 1),

Longitudinal elastic modulus E (kgf / mm ² ) of a layer (C layer) on the side opposite to the side in contact with the sealing material layer (IV) of the back surface protection substrate (V) for the solar cell module, and the C layer Linear expansion coefficient of CTE

C

(10 V ° O and the thickness h (mm) of the C layer, which is derived according to the following formula (2),

C C

C C I

Solar cell module.

Formula (1): F = E X CTE X h

Formula (2): F = E X CTE X h

c c c c

Formula (3): 0. 7≤F / F≤l. 3

C I

Including a laminate in which at least three layers are laminated,

A back protective substrate for a solar cell module, wherein the laminate has a composite material layer containing at least one layer of thermoplastic resin and reinforcing fiber, and a layer having a resin foam strength.