CN104934494A - Composite backboard used for solar cell and solar cell module including the composite backboard - Google Patents

Abstract

The present invention relates to a composite back sheet for solar cells and a solar cell module containing the same, the composite back sheet for solar cells comprises an outer layer, a first adhesive layer, an intermediate layer, and a second adhesive layer in the following order and an inner layer, wherein the outer layer comprises a polypropylene-based composite material, the intermediate layer has a polymer having a power frequency electric strength greater than 55 V/μm, and the inner layer comprises a polyethylene base or an ethylene-vinyl acetate copolymer base Composite material, and the interlayer peeling strength with encapsulation EVA for solar cells is greater than 40N/cm, the composite backsheet has a water vapor permeability lower than 2.0g/ ^m2 day, and preferably at 420nm-640nm Has at least 90% light reflectivity in the wavelength range. The composite backsheet for solar cells has both excellent water vapor barrier properties and interlayer peel strength.

Description

Composite back sheet for solar cell and solar cell module containing same

technical field

The invention relates to a composite back plate for solar cells and a solar cell module containing the same.

Background technique

With the massive consumption of non-renewable resources such as coal, oil, and natural gas, the world has to turn its attention to these fields of renewable energy, such as solar energy, wind energy, and tidal energy. There are currently three ways for humans to utilize solar energy: 1. photothermal conversion (solar water heater); 2. photoelectric conversion (photovoltaic cells); 3. photochemical conversion (still in the laboratory stage).

For the production of solar cells, it is usually necessary to combine various component materials such as battery sheets, packaging films, aluminum frames, composite films (commonly known as composite backsheets), etc. Combined to achieve electrical, water vapor barrier and other weather resistance requirements. Commonly used composite backsheets on the market can be roughly divided into fluorine-containing materials and fluorine-free materials according to the outer layer materials. Examples of fluorine-containing composite backsheets include DuPont Tedlar's PVF fluorine-containing composite backsheets, Arkema Kynar's PVDF fluorine-containing composite backsheet, Honeywell ECTFE fluorine-containing composite backsheet material, Saint-Gobain ETFE fluorine-containing composite backsheet material, and 3M Dyneon THV fluorine-containing composite backsheet material, etc. Fluorine-free materials, such as Coveme PPE, ISOVOLTAIC (APA, 3A), and multi-layer co-extruded polyolefin composite backsheets, are more and more environmentally friendly and low-cost, and are more and more popular among component manufacturers. However, the existing composite backsheets (fluorine-containing and fluorine-free) still have the following problems: poor UV resistance (especially fluorine-free composite backsheets), easy yellowing, high water vapor transmission rate, and weak reflective performance (<85%) resulting in low power output, and the co-extruded polyolefin composite backsheet is easy to shrink and wrinkle, and is not easy to handle. There are also some backplanes that have the disadvantages of easy cracking and pulverization of the outer layer after humid heat aging, the adhesive needs to be cured for a long time, the production cycle is long, and the cost is high.

Contents of the invention

The object of the present invention is to provide a composite backsheet having both excellent water vapor barrier properties and interlayer peel strength, and a solar cell module including the composite backsheet according to the present invention.

According to the present invention, provide following technical scheme:

1. A composite back sheet for solar cells comprising an outer layer, a first adhesive layer, an intermediate layer, a second adhesive layer and an inner layer in the following order, wherein the outer layer comprises a polypropylene-based composite material , the middle layer has a polymer with a power frequency electric strength greater than 55V/μm, the inner layer contains polyethylene or ethylene-vinyl acetate copolymer-based composite materials, and is used for encapsulating EVA for solar cells. The peel strength is greater than 40 N/cm, wherein the composite backsheet has a water vapor permeability of less than 2.0 g/m ² d.

2. The composite back sheet for solar cells according to item 1, wherein the thickness ratio of the outer layer to the middle layer is in the range of 3:1 to 1:12, and the thickness ratio of the middle layer to the inner layer is The thickness ratio is in the range of 12:1 to 1:5, and the total thickness of the composite backsheet is greater than 250 μm.

3. The composite backsheet for solar cells according to item 2, wherein the thickness ratio of the outer layer to the middle layer is in the range of 2:1 to 1:8, and the thickness of the middle layer to the inner layer is The ratio of the thicknesses of the layers is in the range of 8:1 to 1:3.

4. The composite back sheet for solar cells according to item 2, wherein the thickness ratio of the outer layer to the middle layer is in the range of 1:2 to 1:6, and the thickness of the middle layer to the inner layer is The ratio of the thicknesses of the layers is in the range of 4:1 to 1:2.

5. The composite back sheet for solar cells according to item 1, wherein the polypropylene-based composite material comprises polypropylene, an inorganic filler, an anti-ultraviolet additive, a toughening agent, and an antioxidant.

6. The composite back sheet for solar cells according to item 5, wherein the polypropylene-based composite material further comprises other olefin polymers other than polypropylene.

7. The composite back sheet for solar cells according to item 6, wherein the other olefin polymer comprises one or more of polyethylene and ethylene-vinyl acetate copolymer.

8. The composite back sheet for solar cells according to item 1, wherein the polyethylene-based composite material comprises polyethylene, an inorganic filler, an anti-ultraviolet additive, and an antioxidant.

9. The composite back sheet for solar cells according to item 1, wherein the ethylene-vinyl acetate copolymer-based composite material comprises an ethylene-vinyl acetate copolymer, an inorganic filler, an anti-ultraviolet additive, and an antioxidant.

10. The composite back sheet for solar cells according to item 8, wherein the polyethylene-based composite material further contains other olefin polymers other than polyethylene.

11. The composite back sheet for solar cells according to item 9, wherein the ethylene-vinyl acetate copolymer-based composite material further comprises other olefin polymers other than ethylene-vinyl acetate copolymer.

12. The composite back sheet for solar cells according to item 10 or 11, wherein the other olefin polymer comprises a propylene copolymer.

13. The composite back sheet for solar cells according to item 1, wherein the polymer having a power frequency electric strength greater than 55 V/μm comprises polyethylene terephthalate, polycarbonate, polyethylene naphthalate One or more of glycol esters, polybutylene terephthalate and polymethyl methacrylate.

14. The composite back sheet for solar cells according to item 1, wherein the intermediate layer has a thickness of 25 micrometers to 300 micrometers.

15. The composite back sheet for solar cells according to item 1, wherein the outer layer has a thickness of 25 micrometers to 250 micrometers.

16. The composite back sheet for solar cells according to item 1, wherein the inner layer has a thickness of 25 micrometers to 150 micrometers.

17. The composite back sheet for solar cells according to item 5, wherein the toughening agent comprises maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, ethylene-vinyl acetate, and polyolefin elastomer One or more of POE.

18. The composite back sheet for solar cells according to item 8 or 9, wherein the inorganic filler comprises one or more of calcium carbonate, titanium dioxide, montmorillonite, kaolin, barium sulfate and hydrotalcite.

19. The composite backsheet for solar cells according to item 8 or 9, wherein the anti-ultraviolet additives include salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines and hindered One or more of amines.

20. The composite backsheet for solar cells according to item 8 or 9, wherein the antioxidant is one or more of aromatic amines, hindered phenols and phosphites.

21. The composite back sheet for solar cells according to item 1, wherein the first adhesive layer and/or the second adhesive layer has a thickness of 1˜10 μm.

22. The composite back sheet for solar cells according to item 1, wherein the adhesive contained in the first adhesive layer comprises a polyurethane adhesive, an epoxy adhesive, an acrylic adhesive and one or more of modified polyolefin adhesives.

23. The composite back sheet for solar cells according to item 1, wherein the adhesive contained in the second adhesive layer comprises a polyurethane adhesive, an epoxy adhesive, an acrylic adhesive , one or more of modified polyolefin adhesives, titanate adhesives and silane adhesives.

24. The composite back sheet for solar cells according to item 1, wherein the outer layer has a melting point of 160° C. or higher and a water vapor permeability lower than 10 g/m ² d.

25. The composite back sheet for solar cells according to item 1, wherein the composite back sheet for solar cells has a light reflectance of at least 90% in the wavelength range of 420 nm to 640 nm.

26. A solar cell module comprising the composite back sheet for solar cells according to any one of items 1 to 25.

Beneficial effect

The composite backsheet according to the present invention simultaneously has excellent water vapor barrier properties and interlayer peel strength. In addition, the composite back sheet according to the present invention can also have excellent light reflectivity and the solar cell module has high output power. In addition, the composite back sheet according to the present invention can also have an anti-ultraviolet function, and does not require additional curing time, thereby greatly shortening the production cycle of the composite back sheet and reducing the cost.

Description of drawings

Fig. 1 is a schematic structural view of a composite backplane according to the present invention.

Fig. 2 is a schematic structural view of a solar cell module including a composite back sheet according to the present invention.

Fig. 3 shows the light reflectance of the composite backsheet (Example 3) of the present invention in the wavelength range of 200nm-1100nm.

Fig. 4 shows the change of YI, b value of the outer layer of the composite backsheet (Example 3) of the present invention under ultraviolet irradiation.

Fig. 5 shows the change of YI, b value of the inner layer of the composite backsheet (Example 3) of the present invention under ultraviolet irradiation.

Figure 6 shows the water vapor transmission rate of the composite backsheet of the present invention (Example 3).

Detailed ways

The composite backsheet for solar cells according to the present invention comprises an outer layer, a first adhesive layer, an intermediate layer, a second adhesive layer and an inner layer in the following order, wherein the outer layer comprises a polypropylene-based composite material, so The middle layer has a polymer with a power frequency electric strength greater than 55V/μm, the inner layer contains polyethylene or ethylene-vinyl acetate copolymer-based composite materials, and has an interlayer peel strength of EVA used for encapsulation of solar cells Greater than 40 N/cm, wherein the composite backsheet has a water vapor permeability of less than 2.0 g/m ² day. Preferably, the composite backsheet has a light reflectance of at least 90% in the wavelength range of 420nm-640nm.

Fig. 1 is a schematic structural view of a composite backplane according to the present invention. As shown in Figure 1, according to the composite backsheet for solar cells of the present invention, it comprises an outer layer 1a, an intermediate layer 2a and an inner layer 3a, and a first adhesive layer 4a arranged between the outer layer 1a and the intermediate layer 2a and an adhesive layer arranged on the Second adhesive layer 5a between intermediate layer 2a and inner layer 3a.

Each layer of the composite back sheet for solar cells of the present invention is described in detail below.

outer layer

According to the invention, the outer layer is a layer comprising a polypropylene-based composite material. Preferably, the outer layer has a melting point above 160° C. and a water vapor permeability below 10 g/m ² day. The polypropylene-based composite material may contain polypropylene, inorganic fillers, anti-ultraviolet additives, toughening agents and antioxidants.

The inorganic filler includes calcium carbonate, titanium dioxide, preferably rutile titanium dioxide, such as one or more of Dupont R105, montmorillonite, kaolin, barium sulfate and hydrotalcite.

The anti-ultraviolet additive can be an organic ultraviolet absorber or stabilizer. The organic ultraviolet absorber or stabilizer includes one or more of salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines and hindered amines. Specific examples of anti-UV additives include UV-9 (2-hydroxy-4-methoxybenzophenone), UV-531 (2-hydroxy-4-n-octyloxy-benzophenone), UV-326 [(2′-Hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole], UV-P[2-(2′-Hydroxy-5′-methyl phenyl)benzotriazole], UV-24 (2,2′-dihydroxy-methoxybenzophenone), triazine-5[2,4,6-tris(2′-hydroxy-4′ -n-octyloxyphenyl)-1,3,5-triazine], TINUVIN622, TINUVIN770, TINUVIN783, TINUVINP, TINUVIN788 and the like.

The toughening agent comprises one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, ethylene-vinyl acetate, and polyolefin elastomer POE.

The antioxidant is one or more of aromatic amines, hindered phenols and phosphites. Specific examples of antioxidants include BASF Antioxidants 1010 and 168, and B215.

The polypropylene-based composite also contains other olefinic polymers than polypropylene. The other olefin polymers include one or more of polyethylene and ethylene-vinyl acetate copolymer.

When the outer layer contains polypropylene, inorganic fillers, anti-ultraviolet additives, toughening agents and antioxidants, based on the total weight of the outer layer, the weight ratio of polypropylene is preferably in the range of 65% to 94%, and the weight ratio of inorganic fillers Preferably in the range of 5% to 25%, the weight ratio of the anti-ultraviolet additive is preferably in the range of 0.1% to 1.5%, the weight ratio of the toughening agent is preferably in the range of 0.5% to 5%, and the weight ratio of the antioxidant It is preferably in the range of 0.1% to 1.0%.

When the outer layer comprises polypropylene, other olefin polymers, inorganic fillers, anti-ultraviolet additives, toughening agents and antioxidants, based on the total weight of the outer layer, the weight ratio of polypropylene is preferably in the range of 55% to 84%, Other olefin polymers are preferably in the range of 2% to 15%, the weight ratio of inorganic fillers is preferably in the range of 5% to 25%, the weight ratio of anti-ultraviolet additives is preferably in the range of 0.1% to 1.5%, toughening The weight ratio of the agent is preferably in the range of 0.5 to 5%, and the weight ratio of the antioxidant is preferably in the range of 0.1% to 1.0%.

The outer layer has a thickness of 25 microns to 250 microns.

first adhesive layer

The adhesive contained in the first adhesive layer may be an ordinary adhesive as long as it can achieve strong adhesion between the outer layer and the middle layer. The adhesive contained in the first adhesive layer may also be a developed special adhesive.

The adhesive contained in the first adhesive layer may comprise one or more of polyurethane adhesive, epoxy adhesive, acrylic adhesive and modified polyolefin adhesive, Epoxy-based adhesives and modified polyolefin-based adhesives are preferred, and modified polyolefin-based adhesives are particularly preferred.

In particular, when epoxy adhesive or modified polyolefin adhesive or their combination is used as the first adhesive layer, compared with other adhesives, the amount of glue applied is small and does not need to be cured, which can be significantly improved. Shorten the production cycle of the composite backsheet and greatly enhance the interlayer peel strength.

The thickness of the first adhesive layer may be 1-10 microns.

middle layer

According to the invention, the intermediate layer has a polymer having a power-frequency electric strength greater than 55 V/μm. Power frequency electric strength can be measured by methods known in the art.

Polymers of the intermediate layer meeting the above requirements may include polyethylene terephthalate, polycarbonate, polyethylene naphthalate, polybutylene terephthalate and polymethyl methacrylate one or more of.

The thickness of the intermediate layer is 25 microns to 300 microns.

second adhesive layer

The adhesive contained in the second adhesive layer may be an ordinary adhesive as long as it can achieve strong adhesion between the inner layer and the middle layer. The adhesive contained in the second adhesive layer may also be a developed special adhesive.

The adhesive contained in the second adhesive layer may include polyurethane-based adhesives, epoxy-based adhesives, acrylic-based adhesives, modified polyolefin-based adhesives, titanate-based, and silane-based adhesives. One or more of adhesives, preferably epoxy adhesives and modified polyolefin adhesives, particularly preferably modified polyolefin adhesives. The second adhesive may be the same or different from the first adhesive.

In particular, when epoxy adhesive or modified polyolefin adhesive or their combination is used as the second adhesive layer, compared with other adhesives, the amount of glue applied is small and no curing is required, which can significantly Shorten the production cycle of the composite backsheet and greatly enhance the interlayer peel strength.

The thickness of the second adhesive layer may be 1-10 microns.

inner layer

According to the invention, the inner layer comprises a polyethylene-based composite material or an ethylene-vinyl acetate copolymer-based composite material and has an interlaminar peel strength of more than 40 N/cm with the encapsulating EVA for solar cells. Preferably, the inner layer has a light reflectivity of at least 90% in the wavelength range of 420nm-640nm.

The polyethylene-based composite material may contain polyethylene, inorganic fillers, anti-ultraviolet additives and antioxidants. The polyethylene-based composite material may also contain other olefinic polymers than polyethylene. The other olefin polymers include propylene copolymers.

The ethylene-vinyl acetate copolymer-based composite material may include ethylene-vinyl acetate copolymer, inorganic fillers, anti-ultraviolet additives, and antioxidants. The ethylene-vinyl acetate copolymer-based composite also includes other olefin polymers other than ethylene-vinyl acetate copolymer. The other olefin polymers include propylene copolymers.

The inorganic filler includes calcium carbonate, titanium dioxide, preferably rutile titanium dioxide, such as one or more of Dupont R105, montmorillonite, kaolin, barium sulfate and hydrotalcite.

The anti-ultraviolet additive can be an organic ultraviolet absorber or stabilizer. The organic ultraviolet absorber or stabilizer includes one or more of salicylates, benzophenones, benzotriazoles, substituted acrylonitriles, triazines and hindered amines. Specific examples of anti-UV additives include UV-9 (2-hydroxy-4-methoxybenzophenone), UV-531 (2-hydroxy-4-n-octyloxy-benzophenone), UV-326 [(2′-Hydroxy-3′-tert-butyl-5′-methylphenyl)-5-chlorobenzotriazole], UV-P[2-(2′-Hydroxy-5′-methyl phenyl)benzotriazole], UV-24 (2,2′-dihydroxy-methoxybenzophenone), triazine-5[2,4,6-tris(2′-hydroxy-4′ -n-octyloxyphenyl)-1,3,5-triazine], TINUVIN622, TINUVIN770, TINUVIN783, TINUVINP, TINUVIN788 and the like.

The antioxidant contains one or more of aromatic amines, hindered phenols and phosphites. Specific examples of antioxidants include BASF Antioxidants 1010 and 168, and B215.

When the inner layer contains polyethylene or ethylene-vinyl acetate copolymer, inorganic fillers, anti-ultraviolet additives and antioxidants, based on the total weight of the inner layer, the weight ratio of polyethylene or ethylene-vinyl acetate copolymer is preferably 75% In the range of ~94%, the weight ratio of inorganic filler is preferably in the range of 5~25%, the weight ratio of anti-ultraviolet additive is preferably in the range of 0.1%~1.5%, and the weight ratio of antioxidant is preferably in the range of 0.1%~ 1.0% range.

When the inner layer contains polyethylene or ethylene-vinyl acetate copolymer, other olefin polymers, inorganic fillers, anti-ultraviolet additives, and antioxidants, based on the total weight of the inner layer, the polyethylene or ethylene-vinyl acetate copolymer The weight ratio is preferably in the range of greater than 0% to 75%, other olefin polymers are preferably in the range of 1-75%, the weight ratio of inorganic fillers is preferably in the range of 5-25%, and the weight ratio of anti-ultraviolet additives is preferably It is in the range of 0.1% to 1.5%, and the weight ratio of the antioxidant is preferably in the range of 0.1% to 1.0%.

The inner layer has a thickness of 25 microns to 150 microns.

The inventors of the present invention also found that in the five-layer structure of the composite backsheet, when the thickness ratio of the outer layer to the middle layer is in the range of 3:1 to 1:12, preferably in the range of 2:1 to 1: 8, more preferably in the range of 1:2 to 1:6; the ratio of the thickness of the middle layer to the inner layer is in the range of 12:1 to 1:5, preferably in the range of 8:1 to 1 :3, more preferably in the range of 4:1 to 1:2; and when the total thickness of the composite backsheet is more than ²⁵⁰ microns, the composite backsheet has In addition to the high water vapor permeability and at least 90% light reflectivity in the wavelength range of 420nm-640nm, it also has a partial discharge of greater than 1,000V. At the same time, compared with similar backsheet products, such a composite backsheet is easier to process (for example, its corresponding lamination process conditions, including temperature, duration, etc., will be more relaxed), and its production cost is lower.

solar cell module

Fig. 2 is a schematic structural view of a solar cell module including a composite back sheet according to the present invention. As shown in Figure 2, the solar cell assembly comprises a glass plate 2, packaging material EVA (ethylene-vinyl acetate copolymer) 3, battery sheet 4, composite back sheet 5 of the present invention, positive pole 6, negative pole 7 and electrode separator EPE8 . When the composite back sheet 5 of the present invention is installed in a solar cell module, the inner layer faces the encapsulation material EVA (ethylene-vinyl acetate copolymer) 3 and the outer layer faces the air side. When the solar cell module is working, sunlight 1 enters from the glass 2 side of the solar cell module.

The composite back sheet and solar cell module according to the present invention can be manufactured according to conventional methods.

Example

Hereinafter, the present invention will be specifically described by using examples. However, the present invention is not limited to or by these Examples. Parts in the examples are by weight unless otherwise indicated.

Example 1

90 parts of polypropylene PP particles used for the outer layer, 2 parts of toughening agent (maleic anhydride grafted polypropylene (graft rate 5%)), 0.5 part of ultraviolet stabilizer (TINUVIN622), titanium dioxide (R105) 7 parts, 0.5 parts of antioxidant (B215) at room temperature (10 ~ 30 ° C), at a speed of 500 rpm, add to the mixer in batches through the side feeding port for mixing and fully stir for half an hour, then at 220 ° C Next, extrude a film with a thickness of 80 μm as the outer layer.

Use 91 parts of polyethylene PE particles for the inner layer, 0.5 parts of ultraviolet stabilizer (CYASORB THT7001), 8 parts of titanium dioxide, and 0.5 parts of antioxidant (B215), at room temperature (10-30 ° C), at 500 rpm The rotation speed is high, and it is fed into the mixer in batches through the side feeding port for mixing and fully stirred for half an hour, and then extruded into a film with a thickness of 50 μm at a temperature of 230 ° C as the inner layer.

Apply about 3 μm of adhesive 1 (a mixture of modified polyolefin glue and epoxy glue) on one side of 188 μm white PET (manufactured by Foshan DuPont, brand BP series) after air corona, and heat through 100 degrees. Oven drying to obtain the first adhesive layer. The above outer layer is composited on the first adhesive layer. Then, apply about 3 μm of adhesive 2 (a mixture of modified polyolefin glue and silane coupling agent (KH550)) on the other side of the PET, and dry it in a 100-degree oven to obtain the second adhesive layer . Then compound the above inner layer on the second adhesive layer to obtain the composite backsheet 1 of the present invention.

Example 2

90 parts of polypropylene PP particles used for the outer layer, 2 parts of polypropylene grafted with maleic anhydride (graft rate 5%), 0.5 parts of ultraviolet stabilizer (UV3346), and 7 parts of titanium dioxide (R105) , 0.5 parts of antioxidant (B215) at room temperature (10 ~ 30 ° C), at a speed of 500 rpm, through the side feeding port into the mixer in batches for mixing and fully stirred for half an hour, and then at 220 ° C temperature, A film was extruded at a thickness of 150 μm as the outer layer.

91 parts of polyethylene PE particles used for the inner layer, 0.5 parts of ultraviolet stabilizer (UV3853), 8 parts of titanium dioxide, and 0.5 parts of antioxidant (B215) are used at room temperature (10-30°C) at 500 rpm Rotating speed, feed into the mixer in batches through the side feeding port for mixing and fully stir for half an hour, and then extrude into a film with a thickness of 100 μm at a temperature of 230°C as the inner layer.

Apply about 3 μm adhesive 1 (a mixture of modified polyolefin glue and epoxy glue) on one side of 250 μm white PET (the manufacturer is Dongcai Technology, the brand is DS series) after air corona, and after 100 Dry in an oven to obtain the first adhesive layer. The above outer layer is composited on the first adhesive layer. Then, apply about 3 μm of adhesive 2 (a mixture of modified polyolefin glue and silane coupling agent (KH550)) on the other side of the PET, and dry it in a 100-degree oven to obtain the second adhesive layer . Then compound the above inner layer on the second adhesive layer to obtain the composite backsheet 2 of the present invention.

Example 3

80 parts of polypropylene PP particles for the outer layer, 10 parts of polyethylene, 2 parts of polypropylene grafted with maleic anhydride (graft rate 5%) of toughening agent, 0.5 part of ultraviolet stabilizer (TINUVIN622), titanium dioxide (R105) 7 parts, antioxidant (B215) 0.5 parts at room temperature (10 ~ 30 ° C), at a speed of 500 rpm, through the side feeding port into the mixer in batches for mixing and fully stirred for half an hour, and then in Extruded into a film with a thickness of 80 μm at a temperature of 220° C. as the outer layer.

Use 91 parts of polyethylene PE particles for the inner layer, 0.5 parts of ultraviolet stabilizer (CYASORB THT7001), 8 parts of titanium dioxide, and 0.5 parts of antioxidant (B215), at room temperature (10-30 ° C), at 500 rpm The rotation speed is high, and it is fed into the mixer in batches through the side feeding port for mixing and fully stirred for half an hour, and then extruded into a film with a thickness of 50 μm at a temperature of 230 ° C as the inner layer.

Apply about 3 μm of adhesive 1 (a mixture of modified polyolefin glue and epoxy glue) on one side of 188 μm white PET (manufactured by Foshan DuPont, brand BP series) after air corona, and heat through 100 degrees. Oven drying to obtain the first adhesive layer. The above outer layer is composited on the first adhesive layer. Then, apply about 3 μm of adhesive 2 (a mixture of modified polyolefin glue and silane coupling agent (KH550)) on the other side of the PET, and dry it in a 100-degree oven to obtain the second adhesive layer . Then compound the above inner layer on the second adhesive layer to obtain the composite back sheet 3 of the present invention.

Example 4

80 parts of polypropylene PP particles for the outer layer, 10 parts of polyethylene, 2 parts of polypropylene grafted with maleic anhydride (graft rate 5%) of toughening agent, 0.5 part of ultraviolet stabilizer (TINUVIN622), titanium dioxide (R105) 7 parts, antioxidant (B215) 0.5 parts at room temperature (10 ~ 30 ° C), at a speed of 500 rpm, through the side feeding port into the mixer in batches for mixing and fully stirred for half an hour, and then in Extruded into a film with a thickness of 80 μm at a temperature of 220° C. as the outer layer.

Put 91 parts of ethylene vinyl acetate EVA particles, 0.5 parts of ultraviolet stabilizer (CYASORB THT7001), 8 parts of titanium dioxide, and 0.5 parts of antioxidant (B215), at room temperature (10-30 ° C), at a speed of 500 rpm, Add it into the mixer in batches through the side feeding port for mixing and fully stir for half an hour, and then extrude at a temperature of 220°C with a thickness of 50 μm as the inner layer.

Apply about 3 μm of adhesive 1 (a mixture of modified polyolefin glue and epoxy glue) on one side of 188 μm white PET (manufactured by Foshan DuPont, brand BP series) after air corona, and heat through 100 degrees. Oven drying to obtain the first adhesive layer. The above outer layer is composited on the first adhesive layer. Then, apply about 3 μm of adhesive 2 (a mixture of modified polyolefin glue and silane coupling agent (KH550)) on the other side of the PET, and dry it in a 100-degree oven to obtain the second adhesive layer . Then compound the above inner layer on the second adhesive layer to obtain the composite back sheet 4 of the present invention.

Example 5

80 parts of polypropylene PP particles for the outer layer, 10 parts of polyethylene, 2 parts of polypropylene grafted with maleic anhydride (graft rate 5%) of toughening agent, 0.5 part of ultraviolet stabilizer (TINUVIN622), titanium dioxide (R105) 7 parts, antioxidant (B215) 0.5 parts at room temperature (10 ~ 30 ° C), at a speed of 500 rpm, through the side feeding port into the mixer in batches for mixing and fully stirred for half an hour, and then in Extruded into a film with a thickness of 80 μm at a temperature of 220° C. as the outer layer.

45.5 parts of PP triblock copolymer (copolymer of propylene, ethylene and octene) used for the inner layer, 45.5 parts of EVA particles, 0.5 parts of ultraviolet stabilizer (CYASORB THT7001), 8 parts of titanium dioxide, antioxidant (B215) 0.5 parts, at room temperature (10-30°C), at a speed of 500 rpm, add it to the mixer in batches through the side feeding port for mixing and fully stir for half an hour, then at 220°C, use 50μm The thickness is extruded into a film as the inner layer.

Apply about 3 μm of adhesive 1 (a mixture of modified polyolefin glue and epoxy glue) on one side of 188 μm white PET (manufactured by Foshan DuPont, brand BP series) after air corona, and heat through 100 degrees. Oven drying to obtain the first adhesive layer. The above outer layer is composited on the first adhesive layer. Then, apply about 3 μm of adhesive 2 (a mixture of modified polyolefin glue and silane coupling agent (KH550)) on the other side of the PET, and dry it in a 100-degree oven to obtain the second adhesive layer . Then compound the above inner layer on the second adhesive layer to obtain the composite back sheet 5 of the present invention.

Example 6

80 parts of polypropylene PP particles for the outer layer, 10 parts of polyethylene, 2 parts of polypropylene grafted with maleic anhydride (graft rate 5%) of toughening agent, 0.5 part of ultraviolet stabilizer (TINUVIN622), titanium dioxide (R105) 7 parts, antioxidant (B215) 0.5 parts at room temperature (10 ~ 30 ° C), at a speed of 500 rpm, through the side feeding port into the mixer in batches for mixing and fully stirred for half an hour, and then in Extruded into a film with a thickness of 80 μm at a temperature of 220° C. as the outer layer.

Use 91 parts of polyethylene PE particles for the inner layer, 0.5 parts of ultraviolet stabilizer (CYASORB THT7001), 8 parts of titanium dioxide, and 0.5 parts of antioxidant (B215), at room temperature (10-30 ° C), at 500 rpm The rotation speed is high, and it is fed into the mixer in batches through the side feeding port for mixing and fully stirred for half an hour, and then extruded into a film with a thickness of 50 μm at a temperature of 230 ° C as the inner layer.

Apply an adhesive 1 (a mixture of modified polyolefin glue and epoxy glue) of about 3 μm on one side of the 188 μm PC (manufactured by Bayer Technology, brand MakrofolTP244 series) after air corona, and pass through a 100-degree oven drying to obtain the first adhesive layer. The above outer layer is composited on the first adhesive layer. Then, apply an adhesive 2 (a mixture of modified polyolefin glue and silane coupling agent (KH550)) of about 3 μm on the other side of the PC, and dry it in a 100-degree oven to obtain the second adhesive layer . Then compound the above inner layer on the second adhesive layer to obtain the composite backsheet 6 of the present invention.

Example 7-12

Laminate the glass plate, encapsulating EVA, battery sheet, encapsulating EVA layer and the composite back sheet of the present invention prepared in Examples 1-6 at 145°C for 15 minutes in the above order to obtain a solar cell module.

Comparative example 1

Laminate the glass plate, encapsulating EVA, battery sheet, encapsulating EVA layer and prior art back sheet COVEME dyMat PYE SPV in the above order at 145 degrees for 15 minutes to obtain a solar cell module.

The performances of the composite back sheets of the present invention prepared in Examples 1-6 and the solar cell modules of the present invention prepared in Examples 7-12 and Comparative Example 1 were tested and evaluated as follows. Peel strength between layers

The interlayer peel strength between the outer layer and the middle layer of the composite backsheet is measured according to ASTM D1876. The interlayer peel strength between the inner layer in the composite backsheet and the encapsulating EVA for solar cells was determined according to ASTM D903.

Light reflectivity

The light reflectance of the composite backplane is measured in the wavelength range of 250nm-1100nm using a Lamda950 instrument.

UV resistance

The anti-ultraviolet performance of the composite backsheet is tested in accordance with ASTM G154cycle1, under the irradiation intensity of 120kWh/m ² ultraviolet rays, and the yellowing index (Yellow Index) is characterized in accordance with ASTM D1925.

water vapor transmission rate

The water vapor transmission rate of the composite backsheet was measured in accordance with ASTM F1249 at 37.8°C/100%RH.

Output Power

The output power of the solar cell module was measured in accordance with IEC61215 using a Spire simulator.

Table 1 shows the interlaminar peel strength between the outer layer and the middle layer and between the inner layer and the middle layer in the composite backsheet of Example 3.

Table 1

As shown in Table 1, the interlaminar peel strength between the outer layer and the middle layer in the composite backsheet is as high as 10.6 N/cm, and even after 2000 hours of wet heat aging, it still maintains an excellent peel strength of 7.1 N/cm, and The interlayer peel strength between the inner layer and the middle layer is greater, and the inner layer and the middle layer cannot be separated.

Table 2 shows the interlayer peel strength between the inner layer in the composite backsheet of Example 3 and the encapsulating EVA for solar cells.

Table 2

As shown in Table 2, the interlayer peel strength between the inner layer in the composite backsheet and the encapsulating EVA used for solar cells is as high as 65 N/cm, and it can maintain good adhesion even after 2000 hours of damp heat aging. Knot.

Fig. 3 shows the light reflectance of the composite backplane of the present invention in the wavelength range of 200nm-1100nm. As shown in FIG. 3 , the composite backplane of the present invention has a light reflectance of at least 90% in the visible light region (420nm-640nm), which enables it to further increase the output power of the module.

Figure 4 shows the YI (yellowing index), b (yellowness) value change of the outer layer of the composite back sheet of the present invention under ultraviolet irradiation, and Fig. 5 shows the inner layer of the composite back sheet of the present invention under ultraviolet irradiation Under the YI, b value change. As shown in Figures 4 and 5, YI<5, and the appearance color of the outer layer and inner layer does not change visually, and there is no crack on the surface, which shows that the composite back sheet of the present invention has excellent UV resistance.

Figure 6 shows the water vapor transmission rate of the composite backsheet of the present invention. As shown in Figure 6, the composite backsheet of the present invention has a low water vapor transmission rate of 1.7 g/m ² days, wherein the water vapor transmission rate of the outer layer is 9.1 g/m ² days.

In addition, comparing Example 3 with Example 1, it is found that the toughness (200%) of the outer layer of Example 1 is not as good as the toughness (300%) of the outer layer of Example 3, but other properties are similar, for example, the toughness of the outer layer of Example 1 The composite backsheet also has a low water vapor transmission rate of 1.7 g/m ² days.

Embodiment 3 is compared with embodiment 2 to find that the partial discharge voltage of embodiment 3 reaches 1087V, and the partial discharge voltage of embodiment 2 reaches 1530V and the water vapor transmission rate is as low as 1.05g/m ² days, but embodiment 2 The cost of is significantly higher than the cost of embodiment 3, and other properties are similar.

Comparing Example 3 with Example 4, it was found that in the composite back sheet prepared in Example 4, the peel strength between the inner layer and the package EVA reached 80N/cm, and the water vapor transmission rate was higher than that of Example 3, reaching 1.9g /m ² days, and the inner layer has a yellowing index>5 when the ultraviolet radiation intensity is 120kWh/m ² , and other properties are similar.

Comparing Example 3 with Example 5, it is found that the water vapor transmission rate of the composite back sheet made in Example 5 is higher than that of Example 3, reaching 1.95g/ ^m2 days, and the inner layer is exposed to ultraviolet radiation of At 120kWh/m ² , the yellowing index value reaches 4.1, and other properties are similar.

Comparing Example 3 with Example 6, it is found that the composite back sheet of Example 6 has a low water vapor transmission rate of 1.8g/m ² days, and because the PC material is selected as the middle layer, the cost is slightly higher, and other properties are similar .

The water vapor transmission rate of the composite backboard of the above-mentioned embodiment is all lower than 2.0g/m ² days, but the water vapor transmission rate of the backboard of Comparative Example 1 as the prior art is much higher, reaching 2.40g /m ² days.

Table 3 below compares the output power (W) of the monolithic solar cell modules of Examples 7-12 and Comparative Example 1.

table 3

serial number Output power (unit: W) Example 7 245.43 Example 8 245.47 Example 9 245.59 Example 10 245.48 Example 11 245.45 Example 12 245.38 Comparative example 1 245.03

It can be seen from Table 3 that compared with the solar cell module including the prior art back sheet, the output power of the solar cell module including the composite back sheet of the present invention is higher than 0.1%.

It should be understood that the exemplary embodiments described herein should be considered as illustrative and not restrictive. Furthermore, descriptions for each feature or aspect in each embodiment should be applicable to other similar features or aspects in other embodiments.

Although one or more embodiments of the invention have been described with reference to the drawings, it should be understood by those skilled in the art that various forms may be made without departing from the spirit and scope of the invention as defined by the following claims. and changes in details.

Claims (26)

1. a composite back plate used for solar batteries, it comprises skin, the first adhesive phase, intermediate layer, the second adhesive phase and internal layer in the following order, wherein said skin comprises behavior of polypropylene composites, described intermediate layer has the polymer that power frequency electrical strength is greater than 55V/ μm, described internal layer comprises polyvinyl or ethylene-vinyl acetate copolymer based composites, and being greater than 40N/cm with the interlaminar strength of the encapsulation EVA for solar cell, wherein said composite back plate has lower than 2.0g/m ²it water vapor permeation rate.

2. composite back plate used for solar batteries according to claim 1, the gross thickness of wherein said composite back plate is greater than 250 μm, wherein said skin is in the scope of 3: 1 to 1: 12 with the ratio of the thickness in described intermediate layer, and described intermediate layer is in the scope of 12: 1 to 1: 5 with the ratio of the thickness of described internal layer.

3. composite back plate used for solar batteries according to claim 2, wherein said skin is in the scope of 2: 1 to 1: 8 with the ratio of the thickness in described intermediate layer, and described intermediate layer is in the scope of 8: 1 to 1: 3 with the ratio of the thickness of described internal layer.

4. composite back plate used for solar batteries according to claim 2, wherein said skin is in the scope of 1: 2 to 1: 6 with the ratio of the thickness in described intermediate layer, and described intermediate layer is in the scope of 4: 1 to 1: 2 with the ratio of the thickness of described internal layer.

5. composite back plate used for solar batteries according to claim 1, wherein said behavior of polypropylene composites comprises polypropylene, inorganic filler, uvioresistant additive, flexibilizer and antioxidant.

6. composite back plate used for solar batteries according to claim 5, wherein said behavior of polypropylene composites also comprises other olefin polymers except polypropylene.

7. composite back plate used for solar batteries according to claim 6, other olefin polymers wherein said comprise in polyethylene and ethylene-vinyl acetate copolymer one or more.

8. composite back plate used for solar batteries according to claim 1, wherein said polyethylene based composition comprises polyethylene, inorganic filler, uvioresistant additive and antioxidant.

9. composite back plate used for solar batteries according to claim 1, wherein said ethylene-vinyl acetate copolymer based composites comprises ethylene-vinyl acetate copolymer, inorganic filler, uvioresistant additive and antioxidant.

10. composite back plate used for solar batteries according to claim 8, wherein said polyethylene based composition also comprises other olefin polymers in addition to the polyethylene.

11. composite back plates used for solar batteries according to claim 9, wherein said ethylene-vinyl acetate copolymer based composites also comprises other olefin polymers except ethylene-vinyl acetate copolymer.

12. composite back plates used for solar batteries according to claim 10 or 11, other olefin polymers wherein said comprise propylene copolymer.

13. composite back plates used for solar batteries according to claim 1, wherein said have that polymer that power frequency electrical strength is greater than 55V/ μm comprises in PETG, Merlon, PEN, polybutylene terephthalate (PBT) and polymethyl methacrylate one or more.

14. composite back plates used for solar batteries according to claim 1, the thickness in wherein said intermediate layer is 25 microns to 300 microns.

15. composite back plates used for solar batteries according to claim 1, wherein said outer field thickness is 25 microns to 250 microns.

16. composite back plates used for solar batteries according to claim 1, the thickness of wherein said internal layer is 25 microns to 150 microns.

17. composite back plates used for solar batteries according to claim 5, wherein said flexibilizer comprise in the polypropylene of maleic anhydride graft, the polyethylene of maleic anhydride graft, ethylene-vinyl acetate and polyolefin elastomer one or more.

18. composite back plates used for solar batteries according to claim 8 or claim 9, wherein said inorganic filler comprise in calcium carbonate, titanium dioxide, imvite, kaolin, barium sulfate and hydrotalcite one or more.

19. composite back plates used for solar batteries according to claim 8 or claim 9, wherein said uvioresistant additive package is containing one or more in bigcatkin willow esters of gallic acid, benzophenone class, benzotriazole, group-substituted acrylonitrile, triazines and hindered amines.

20. composite back plates used for solar batteries according to claim 8 or claim 9, wherein said antioxidant comprise in aromatic amine, Hinered phenols and phosphorous acid esters one or more.

21. composite back plates used for solar batteries according to claim 1, wherein said first adhesive phase and/or the second adhesive phase have the thickness of 1 ~ 10 micron.

22. composite back plates used for solar batteries according to claim 1, adhesive contained in wherein said first adhesive phase comprise in polyurethane binding, epoxy adhesive, acrylic adhesives and modified polyolefin hydro carbons adhesive one or more.

23. composite back plates used for solar batteries according to claim 1, adhesive contained in wherein said second adhesive phase comprise in polyurethane binding, epoxy adhesive, acrylic adhesives, modified polyolefin hydro carbons adhesive, titanate ester adhesive and silane-based adhesion agent one or more.

24. composite back plates used for solar batteries according to claim 1, wherein said skin have more than 160 DEG C fusing point and lower than 10g/m ²it water vapor permeation rate.

25. composite back plates used for solar batteries according to claim 1, wherein said composite back plate used for solar batteries has the light reflectivity of at least 90% in the wave-length coverage of 420nm-640nm.

26. 1 kinds of solar modules, it comprises the composite back plate used for solar batteries according to any one of claim 1 to 25.