HJT battery packaging adhesive film and preparation method thereof

Abstract

The invention provides an HJT battery packaging adhesive film and a preparation method thereof, and belongs to the technical field of HJT batteries. The packaging adhesive film comprises a first adhesive film and a second adhesive film; the first adhesive film is prepared from the following components by taking the total mass of the first adhesive film as 100%: 80 to 85% of matrix resin, 5 to 10% of modified resin, 5 to 10% of EVA (Ethylene Vinyl Acetate) resin and 1 to 5% of an auxiliary agent; based on the total mass of the second adhesive film being 100%, the second adhesive film comprises the following components: 10-15% of matrix resin, 1-2% of modified resin, 80-85% of EVA resin and 1-5% of an auxiliary agent; the modified resin is prepared by melt grafting reaction of matrix resin, an initiator and a monomer; the mass ratio of the matrix resin to the initiator to the monomer is 100: (0.3-2): (0.2-6); the matrix resin is organic silicon liquid silicone rubber and / or low-density polyethylene; the monomer is at least one of a (methyl) acrylic acid monomer, maleic acid, maleic anhydride, fumaric acid, itaconic acid and itaconic anhydride.

Description

Technical Field

[0001] The present invention belongs to the technical field of HJT batteries, and in particular relates to an HJT battery packaging film and a preparation method thereof. Background Art

[0002] With the development of high-efficiency battery module technology, heterojunction cells (HJT) have become one of the mainstream development trends in the photovoltaic industry. Due to the low-temperature process characteristics of HJT cells, the subsequent high-temperature packaging process of traditional crystalline silicon cells cannot be used, and a suitable low-temperature packaging process needs to be developed. HJT battery components are made of five layers of materials: tempered glass, packaging film, battery cells, packaging film and backplane, which are stacked in sequence and pressed together.

[0003] The packaging film uses EVA (ethylene-vinyl acetate copo) as one of its main materials. EVA has the characteristics of transparency, softness, hot-melt adhesion, low melting temperature, and good melt fluidity, which basically meets the needs of film packaging.

[0004] However, since the surface of HJT cells is a TCO layer plus a silver grid electrode, the conventional EVA film used for encapsulation has a low adhesion to the TCO layer, resulting in a decrease in the reliability of HJT battery components and the risk of delamination after long-term use. Therefore, it is necessary to develop an HJT battery encapsulation film with better adhesion. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides a HJT battery encapsulation adhesive film and a preparation method thereof.

[0006] In a first aspect, an embodiment of the present invention provides a HJT battery encapsulation adhesive film, including a first adhesive film and a second adhesive film;

[0007] Taking the total mass of the first adhesive film as 100%, the first adhesive film comprises the following components: 80-85% of base resin, 5-10% of modified resin, 5-10% of EVA resin, and 1-5% of additives;

[0008] Taking the total mass of the second adhesive film as 100%, the second adhesive film comprises the following components: 10-15% of base resin, 1-2% of modified resin, 80-85% of EVA resin, and 1-5% of additive;

[0009] The modified resin is prepared by melt grafting reaction of a base resin, an initiator and a monomer; the mass ratio of the base resin, the initiator and the monomer is 100:(0.3-2):(0.2-6);

[0010] The base resin is organic silicon liquid silicone rubber and / or low-density polyethylene; the monomer is at least one of (meth) acrylic monomer, maleic acid, maleic anhydride, fumaric acid, itaconic acid and itaconic anhydride.

[0011] The advantages and technical effects brought by the encapsulation film of the embodiment of the present invention are as follows:

[0012] (1) The encapsulation film of the embodiment of the present invention comprises a first film and a second film, wherein the first film has a matrix resin as a main component, and the second film has an EVA resin as a main component, so that the first film has good adhesion to the TCO layer of the HJT battery, and the second film has good adhesion to the tempered glass or the back panel. By adopting a double-layer encapsulation film, the different bonding functions of the two sides of the encapsulation film are guaranteed, and the overall bonding performance of the HJT component is taken into account, thereby improving the reliability of the HJT battery component and greatly reducing the risk of delamination of the HJT battery component after long-term use.

[0013] (2) In the encapsulation film of the embodiment of the present invention, both the first film and the second film contain a base resin, a modified resin, an EVA resin and an additive, thereby enhancing the bonding force between the first film and the second film. In addition, the contents of the base resin, the modified resin and the EVA resin in the double-layer film are different, and the same component forms a concentration gradient in the double-layer film, thereby preventing delamination at the junction of the first film and the second film due to excessive stress.

[0014] (3) The modified resin contained in the encapsulation film of the embodiment of the present invention is prepared by melt grafting reaction of a base resin, an initiator and a monomer, wherein the base resin is organic silicone liquid silicone rubber and / or low-density polyethylene; the monomer is at least one of (meth) acrylic acid monomer, maleic acid, maleic anhydride, fumaric acid, itaconic acid and itaconic anhydride. The modified resin described above can effectively improve the adhesion of the encapsulation film to the TCO layer of the HJT battery.

[0015] In some embodiments, the temperature of the melt grafting reaction is 100-160°C.

[0016] In some embodiments, in the modified resin, the grafting rate of the monomer is 0.2-1%.

[0017] In some embodiments, the modified resin has a melt index of 6-20 g / 10 min.

[0018] In some embodiments, the base resin has a melt index of 10-22 g / 10 min.

[0019] In some embodiments, the EVA resin has a melt index of 8-26 g / 10 min.

[0020] In some embodiments, the auxiliary agent includes a cross-linking agent, a co-cross-linking agent, an ultraviolet light stabilizer, an ultraviolet light absorber and an antioxidant, wherein the mass ratio of the cross-linking agent, the co-cross-linking agent, the ultraviolet light stabilizer, the ultraviolet light absorber and the antioxidant is 1:(0.6-0.8):(0.2-0.4):(0.2-0.4).

[0021] In some embodiments, the thickness of the packaging film is 0.4-1.2 mm; and the ratio of the thickness of the first film to the second film is 1:(2-3).

[0022] In a second aspect, an embodiment of the present invention provides a method for preparing an HJT battery encapsulation film, comprising the following steps: melting the components of the first film and the components of the second film separately, performing double-layer co-extrusion, and pressing them into a film to obtain the encapsulation film of the first aspect.

[0023] The advantages and technical effects brought by the preparation method of the embodiment of the present invention are:

[0024] The preparation method of the embodiment of the present invention is simple to operate, convenient and quick, and the obtained packaging film has excellent adhesion and stability.

[0025] In some embodiments, the melting temperature of the components of the first adhesive film is 60-130°C; the melting temperature of the components of the second adhesive film is 60-100°C. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0027] In a first aspect, an embodiment of the present invention provides a HJT battery encapsulation adhesive film, including a first adhesive film and a second adhesive film;

[0028] Taking the total mass of the first adhesive film as 100%, the first adhesive film comprises the following components: 80-85% of base resin, 5-10% of modified resin, 5-10% of EVA resin, and 1-5% of additives;

[0029] Taking the total mass of the second adhesive film as 100%, the second adhesive film comprises the following components: 10-15% of base resin, 1-2% of modified resin, 80-85% of EVA resin, and 1-5% of additive;

[0030] The modified resin is prepared by melt grafting reaction of a base resin, an initiator and a monomer; the mass ratio of the base resin, the initiator and the monomer is 100:(0.3-2):(0.2-6);

[0031] The base resin is organic silicon liquid silicone rubber and / or low-density polyethylene; the monomer is at least one of (meth) acrylic monomer, maleic acid, maleic anhydride, fumaric acid, itaconic acid and itaconic anhydride.

[0032] The encapsulation film of the embodiment of the present invention includes a first film and a second film, wherein the first film has a matrix resin as a main component, and the second film has an EVA resin as a main component, so that the first film has good adhesion to the TCO layer of the HJT battery, and the second film has good adhesion to the tempered glass or the back panel. By adopting a double-layer encapsulation film, the different bonding functions of the two sides of the encapsulation film are guaranteed, and the overall bonding performance of the HJT component is taken into account, thereby improving the reliability of the HJT battery component and greatly reducing the risk of delamination of the HJT battery component after long-term use.

[0033] In the encapsulation film of the embodiment of the present invention, the first film and the second film both contain a base resin, a modified resin, an EVA resin and an additive, which enhances the bonding force between the first film and the second film. In addition, the contents of the base resin, the modified resin and the EVA resin in the double-layer film are different, and the same component forms a concentration gradient in the double-layer film, thereby preventing delamination at the junction of the first film and the second film due to excessive stress.

[0034] The modified resin contained in the encapsulation film of the embodiment of the present invention is prepared by melt grafting reaction of a base resin, an initiator and a monomer, wherein the base resin is organic silicone liquid silicone rubber and / or low-density polyethylene; the monomer is at least one of (meth) acrylic acid monomer, maleic acid, maleic anhydride, fumaric acid, itaconic acid and itaconic anhydride. The modified resin described above can effectively improve the adhesion of the encapsulation film to the TCO layer of the HJT battery.

[0035] In some embodiments, the temperature of the melt grafting reaction is 100-160°C, such as 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, etc. When the temperature of the melt grafting reaction is too low, the grafting rate of the monomer in the modified resin may be too low, which is not conducive to improving the adhesion between the encapsulation film and the TCO layer of the HJT battery. When the temperature of the melt grafting reaction is too high, it is not conducive to reducing costs and increasing efficiency.

[0036] In some embodiments, in the modified resin, the grafting rate of the monomer is 0.2-1%, such as 0.2%, 0.4%, 0.6%, 0.8%, 1%, etc. When the grafting rate of the monomer in the modified resin is too low, it is not conducive to improving the adhesion between the encapsulation film and the TCO layer of the HJT battery. When the grafting rate of the monomer in the modified resin is too high, the encapsulation film is prone to aging.

[0037] In some embodiments, the initiator is dicumyl peroxide and / or 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0038] In some embodiments, the melt index of the modified resin is 6-20 g / 10 min, such as 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, 18 g / 10 min, 20 g / 10 min, etc.; the melt index of the base resin is 10-22 g / 10 min, such as 10 g / 10 min, 12 g / 10 min, 14 g / 10 min , 16g / 10min, 18g / 10min, 20g / 10min, 22g / 10min, etc.; the melt index of the EVA resin is 8-26g / 10min, such as 8g / 10min, 10g / 10min, 12g / 10min, 14g / 10min, 16g / 10min, 18g / 10min, 20g / 10min, 22g / 10min, 24g / 10min, 26g / 10min, etc. When the melt index of these three resins is within the above range, it can not only improve the adhesion of the encapsulation film, but also avoid problems such as local bubbles in the lamination process of HJT battery components.

[0039] In some embodiments, the auxiliary agent includes a crosslinking agent, a co-crosslinking agent, an ultraviolet light stabilizer, an ultraviolet light absorber and an antioxidant, wherein the mass ratio of the crosslinking agent, the co-crosslinking agent, the ultraviolet light stabilizer, the ultraviolet light absorber and the antioxidant is 1:(0.6-0.8):(0.2-0.4):(0.2-0.4). The above auxiliary agents can improve the anti-aging performance and stability of the encapsulation film.

[0040] In some embodiments, the crosslinking agent can be a peroxide crosslinking agent, such as at least one of tert-butyl hydroperoxide, 1,1-di-tert-butyl peroxy-3,3,5-trimethylcyclohexane, 1,1-di-tert-butyl peroxycyclohexane, tert-amyl peroxy-2-ethylhexyl carbonate, and the like.

[0041] In some embodiments, the auxiliary cross-linking agent may be at least one of triallyl isocyanurate, triallyl cyanurate, and trimethylolpropane triacrylate.

[0042] In some embodiments, the ultraviolet light stabilizer can be a hindered amine light stabilizer, such as at least one of bis-2,2,6,6-tetramethylpiperidinol sebacate, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite.

[0043] In some embodiments, the ultraviolet light absorber may be 2-hydroxy-4-n-octyloxybenzophenone or 3,5-di-tert-butyl-4-hydroxybenzoic acid-2,4-di-tert-butylphenyl ester.

[0044] In some embodiments, the antioxidant may be at least one of tris(2,4-di-tert-butylphenyl)phosphite, 2,2-methylene-bis(-4-methyl-6-tert-butylphenol), and 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid octadecyl.

[0045] In some embodiments, the thickness of the packaging film is 0.4-1.2 mm, such as 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, etc.; the ratio of the thickness of the first film to the second film is 1:(2-3), such as 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, etc. When the thickness of the packaging film and the ratio of the thickness of the first film to the second film are within the above ranges, the overall adhesion and stability of the packaging film can be improved.

[0046] In a second aspect, an embodiment of the present invention provides a method for preparing an HJT battery encapsulation film, comprising the following steps: melting the components of the first film and the components of the second film separately, performing double-layer co-extrusion, and pressing them into a film to obtain the encapsulation film of the first aspect.

[0047] The preparation method of the embodiment of the present invention is simple to operate, convenient and quick, and the obtained packaging film has excellent adhesion and stability.

[0048] In some embodiments, the melting temperature of the components of the first adhesive film is 60-130°C, for example, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, etc.; the melting temperature of the components of the second adhesive film is 60-100°C, for example, 60°C, 70°C, 80°C, 90°C, 100°C, etc.

[0049] The present invention is described in detail below with reference to embodiments.

[0050] Example 1

[0051] A HJT battery packaging film, consisting of a first film and a second film; the packaging film has a thickness of 1 mm, and the ratio of the thickness of the first film to the thickness of the second film is 1:2;

[0052] Taking the total mass of the first adhesive film as 100%, the first adhesive film is composed of the following components: 80% of base resin (organic silicone liquid silicone rubber), 5% of modified resin, 10% of EVA resin, and 5% of additives;

[0053] Taking the total mass of the second adhesive film as 100%, the second adhesive film is composed of the following components: 15% of base resin (organic silicone liquid silicone rubber), 2% of modified resin, 80% of EVA resin, and 3% of additives;

[0054] The modified resin is prepared by melt grafting reaction of base resin (organic silicone liquid silicone rubber), initiator (diisopropylbenzene peroxide) and (meth) acrylic monomer; the temperature of the melt grafting reaction is 120°C, the mass ratio of base resin, initiator and monomer is 100:0.3:0.2, and the grafting rate of monomer in the modified resin is 0.2%;

[0055] The melt index of the modified resin is 15 g / 10 min, the melt index of the base resin is 20 g / 10 min, and the melt index of the EVA resin is 24 g / 10 min;

[0056] The auxiliary agent is composed of a cross-linking agent (1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane), a co-cross-linking agent (triallyl cyanurate), an ultraviolet light stabilizer (N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine), an ultraviolet light absorber (2-hydroxy-4-n-octyloxybenzophenone) and an antioxidant (tris(2,4-di-tert-butylphenyl)phosphite), wherein the mass ratio of the cross-linking agent, the co-cross-linking agent, the ultraviolet light stabilizer, the ultraviolet light absorber and the antioxidant is 1:0.6:0.2:0.2.

[0057] The preparation method of the encapsulation film is as follows:

[0058] (1) Preparation of modified resin: Weigh the components of the modified resin according to the specified mass ratio, mix them in a high-speed mixer, and then put the obtained materials into a twin-screw extruder for melt grafting reaction, extrusion granulation and drying to obtain the modified resin. The temperature of each zone of the twin-screw extruder is set to: 100-110°C for zone I, 105-115°C for zone II, 110-125°C for zone III, 115-130°C for zone IV, 125-140°C for zone V, 135-150°C for zone VI, and 145-160°C for the die.

[0059] (2) Weigh the components of the first film according to the specified mass ratio and mix them in a high-speed mixer; weigh the components of the second film according to the specified mass ratio and mix them in a high-speed mixer; respectively put the two mixed materials into two single-screw extruders of a double-layer co-extrusion casting machine and melt them respectively. The melting temperature of the components of the first film is 100°C; the melting temperature of the components of the second film is 80°C. The melted materials are transported to the co-extrusion die head. The distributor at the inlet of the die head distributes the melted materials of the first film component to the upper layer and the melted materials of the second film component to the lower layer, and transport them to the outlet of the same co-extrusion die head for merging. Use an embossing roller (temperature of 55-65°C) for traction and a cooling roller (temperature of 45-55°C) for cooling to form a film. The draft ratio is 0.9-1.1 to obtain an HJT battery encapsulation film.

[0060] Example 2

[0061] The encapsulation film and the preparation method thereof of this embodiment are the same as those of Embodiment 1, except that the base resin is low-density polyethylene.

[0062] Example 3

[0063] The encapsulation film and the preparation method thereof of this embodiment are the same as those of Embodiment 1, except that the monomer is maleic acid.

[0064] Example 4

[0065] The encapsulation film and the preparation method thereof of this embodiment are the same as those of Embodiment 1, except that the monomer is maleic anhydride.

[0066] Example 5

[0067] The encapsulation film and the preparation method thereof of this embodiment are the same as those of embodiment 1, except that fumaric acid is used.

[0068] Example 6

[0069] The encapsulation film and preparation method thereof of this embodiment are the same as those of Embodiment 1, except that, based on the total mass of the first film being 100%, the first film is composed of the following components: 10% modified resin and 5% EVA resin.

[0070] Example 7

[0071] The encapsulation film and preparation method thereof of this embodiment are the same as those of embodiment 1, except that, based on the total mass of the second film being 100%, the second film is composed of the following components: 10% of base resin (organic silicone liquid silicone rubber) and 85% of EVA resin.

[0072] Example 8

[0073] The encapsulation film and preparation method thereof of this embodiment are the same as those of embodiment 1, except that the mass ratio of the base resin, the initiator and the monomer is 100:2:6, and the grafting rate of the monomer in the modified resin is 1%.

[0074] Comparative Example 1

[0075] A HJT battery packaging film, based on the total mass of the packaging film being 100%, the packaging film is composed of the following components: 97% EVA resin and 3% auxiliary agent, the auxiliary agent is the same as that in Example 1, and the thickness of the packaging film is 1 mm.

[0076] Comparative Example 2

[0077] The encapsulation film and preparation method of this embodiment are the same as those of Embodiment 1, except that, in the first film, the matrix resin (organic silicone liquid silicone rubber) is 90% and does not contain EVA resin; in the second film, the EVA resin is 97% and does not contain matrix resin (organic silicone liquid silicone rubber) and modified resin.

[0078] Peel strength test:

[0079] (1) Sample preparation: The encapsulating films prepared in the embodiments and comparative examples were placed in a vacuum laminator in the order of “tempered glass / encapsulating film / HJT cell / encapsulating film / TPT backplane” according to the test method of GB / T 29848-2018, and laminated at 145° C. for 15 min, wherein the first film of the encapsulating film was in contact with the HJT cell, and the second film was in contact with the tempered glass or TPT backplane.

[0080] (2) Test method: Using a CMT2203 universal electronic stretching machine and following the experimental procedures specified in GB / T 2790-1995, the stretching speed was 100 mm / min, and three samples were tested and the arithmetic mean was taken to obtain the peel strength between the encapsulation film and the tempered glass and the peel strength between the encapsulation film and the HJT cell.

[0081]

[0082] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0083] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A HJT battery encapsulation film, characterized in that: comprising a first adhesive film and a second adhesive film; Taking the total mass of the first adhesive film as 100%, the first adhesive film comprises the following components: 80-85% of base resin, 5-10% of modified resin, 5-10% of EVA resin, and 1-5% of additives; Taking the total mass of the second adhesive film as 100%, the second adhesive film comprises the following components: 10-15% of base resin, 1-2% of modified resin, 80-85% of EVA resin, and 1-5% of additive; The modified resin is prepared by melt grafting reaction of a base resin, an initiator and a monomer; the mass ratio of the base resin, the initiator and the monomer is 100:(0.3-2):(0.2-6); The base resin is organic silicon liquid silicone rubber and / or low-density polyethylene; the monomer is at least one of (meth) acrylic monomer, maleic acid, maleic anhydride, fumaric acid, itaconic acid and itaconic anhydride.

2. The HJT battery encapsulation film according to claim 1, characterized in that: The temperature of the melt grafting reaction is 100-160°C.

3. The HJT battery encapsulation film according to claim 1, characterized in that: In the modified resin, the grafting rate of the monomer is 0.2-1%.

4. The HJT battery encapsulation film according to claim 1, characterized in that: The melt index of the modified resin is 6-20 g / 10 min.

5. The HJT battery encapsulation film according to claim 1, characterized in that: The melt index of the matrix resin is 10-22 g / 10 min.

6. The HJT battery encapsulation film according to claim 1, characterized in that: The melt index of the EVA resin is 8-26 g / 10 min.

7. The HJT battery encapsulation film according to claim 1, characterized in that: The auxiliary agents include a cross-linking agent, a co-cross-linking agent, an ultraviolet light stabilizer, an ultraviolet light absorber and an antioxidant, wherein the mass ratio of the cross-linking agent, the co-cross-linking agent, the ultraviolet light stabilizer, the ultraviolet light absorber and the antioxidant is 1:(0.6-0.8):(0.2-0.4):(0.2-0.4).

8. The HJT battery encapsulation film according to claim 1, characterized in that: The thickness of the packaging film is 0.4-1.2 mm; the ratio of the thickness of the first film to the thickness of the second film is 1:(2-3).

9. The method for preparing the HJT battery encapsulation film according to any one of claims 1 to 8, characterized in that: The following steps are involved: The components of the first adhesive film and the components of the second adhesive film are melted respectively, and then double-layer co-extruded to form a film.

10. The preparation method according to claim 9, characterized in that: The melting temperature of the components of the first adhesive film is 60-130°C; the melting temperature of the components of the second adhesive film is 60-100°C.

Images