Insulation paste composition, insulation paste layer and back contact battery

Abstract

The invention provides an insulation paste composition, an insulation paste layer and a back contact battery. The insulating glue composition comprises the following components in parts by weight: 20-80 parts of matrix resin, 2-10 parts of a curing agent and 5-35 parts of an additive, wherein the additive is selected from organic silicon resin and / or filler, and the weight-average molecular weight of the organic silicon resin is 5000-30000 g / mol. The introduction of the organic silicon can improve the heat resistance, flexibility and wear resistance of the insulating glue, maintain the curing state of the insulating glue at high temperature, inhibit the tackiness of the insulating glue, and improve the stability of the insulating glue at high temperature and under load conditions. The introduction of the filler can improve the mechanical strength, wear resistance and heat resistance of the insulation paste, and improve the insulation performance and environmental aging resistance of the insulation paste, thereby improving the adhesion resistance of the insulation paste under the conditions of high temperature and pressure bearing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to an insulating adhesive composition, an insulating adhesive layer and a back contact cell. BACKGROUND

[0002] The continuous progress of photovoltaic technology has driven the vigorous development of the solar energy industry, among which the back contact cell (BC cell) has become an important direction for the upgrading of photovoltaic technology due to its excellent photoelectric conversion efficiency and beautiful appearance design. In the structure of the BC cell, the high-temperature-resistant insulating adhesive is a key material in the photovoltaic module, which is not only used for isolation between electrodes to ensure the electrical safety of the cell, but also must have excellent insulating properties and environmental aging resistance to cope with various harsh environmental conditions faced by the photovoltaic system during long-term outdoor operation. However, the research and development of high-temperature-resistant insulating adhesives for BC cells are still in the early stages, and most studies focus on improving the weather resistance of the insulating adhesive, i.e. its stability under natural environmental factors such as sunlight, temperature changes, and humidity, but little attention is paid to its performance under conditions of continuous high temperature and mechanical load. However, in the prior art, the insulating adhesive is usually difficult to maintain its cured state under such extreme conditions, and is prone to stickiness, which not only affects the manufacturing quality of the cell module, but also can cause electrode short circuits, directly damaging the electrical safety of the photovoltaic module, reducing the electrical performance (such as insulation and voltage resistance), and even causing safety hazards.

[0003] The existing document (Publication No. CN119060670A) discloses an insulating adhesive for BC cells and a preparation method thereof, which includes component A and component B; by weight, component A at least includes the following components: bisphenol A epoxy resin 40-60 parts, multifunctional epoxy resin 5-30 parts, dimer acid modified epoxy resin 15-25 parts, toughening agent A 5-10 parts, toughening agent B 10-20 parts, coupling agent A 1-3 parts, leveling agent 0.5-2 parts, defoaming agent 0.3-1 part, pigment 0-2 parts; by weight, component B at least includes the following components: modified fatty amine 5-15 parts, modified aromatic amine 5-15 parts, coupling agent B 1-3 parts, solving the problem that the existing insulating adhesive has poor aging resistance, and long-term use under high temperature and humidity or high and low temperature conditions can easily cause the insulating layer in the cell module to appear bulging, delamination, bubbles, discoloration and other adverse phenomena, seriously affecting the reliability and service life of the cell.

[0004] The existing document (Publication No. CN118406466A) discloses an organic silicon insulating adhesive and a preparation method thereof, which uses an alkene-containing polysiloxane resin mixture, methylphenylsiloxane / methylhydrogen siloxane copolymer, tackifying resin, functional filler, catalyst and polymerization inhibitor as raw materials to prepare an organic silicon insulating adhesive, which can well meet the demand of BC solar cells for insulating adhesives.

[0005] However, the insulation glue in the prior art above does not solve the problem that it is easy to stick under the condition of high temperature and high load for a long time.

[0006] In summary, the insulation glue composition and insulation glue layer developed in this application do not stick under the condition of high temperature (≥ 280℃) and load for a long time, which is of great significance to improve the safety of back contact cells. SUMMARY

[0007] The main purpose of the present application is to provide an insulation glue composition, an insulation glue layer and a back contact cell to solve the problem that the insulation glue in the prior art is easy to stick under the condition of high temperature and load for a long time.

[0008] In order to achieve the above-mentioned purpose, the present application provides an insulation glue composition, which comprises, by weight parts: 20-80 parts of a base resin, 2-10 parts of a curing agent and 5-35 parts of an additive; wherein the additive is selected from silicone resin and / or filler; the weight average molecular weight of the silicone resin is 5000-30000 g / mol.

[0009] Further, the additive is a combination of silicone resin and filler, and the weight ratio of silicone resin to filler is (0.7-1.2):(1.9-2.3).

[0010] Further, the insulation glue composition comprises, by weight parts: 20-80 parts of a base resin, 2-10 parts of a curing agent, 5-15 parts of silicone resin and 10-20 parts of filler.

[0011] Further, the weight ratio of the base resin to the curing agent is (3-8):1.

[0012] Further, the base resin is selected from one or more of the group consisting of epoxy resin, polysiloxane resin, polyurethane resin, polybutadiene resin and silicon-containing aryl alkyne resin; preferably, the epoxy value of the epoxy resin is 0.25-0.55 eq / 100g, and the weight average molecular weight is 200-400 g / mol; more preferably, the epoxy resin is selected from one or more of the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin; preferably, the weight average molecular weight of the polysiloxane resin is 10-50 thousand g / mol; preferably, the weight average molecular weight of the polyurethane resin is 80-200 thousand g / mol; preferably, the weight average molecular weight of the polybutadiene resin is 50-200 thousand g / mol; preferably, the weight average molecular weight of the silicon-containing aryl alkyne resin is 2000-10000 g / mol, and the weight percentage content of alkyne group in the silicon-containing aryl alkyne resin is 3.5-6 wt%.

[0013] Further, the organic silicone resin is selected from one or more of the group consisting of an epoxy-modified silicone resin, a polymethylsilsesquioxane, and a polyether-modified siloxane; preferably, the epoxy-modified silicone resin has a functionality of 2 to 4; preferably, the epoxy-modified silicone resin has an epoxy value of 0.05 to 0.2 eq / 100 g.

[0014] Further, the filler has an average particle size of 0.5 to 80 μm and a specific surface area of 0.1 to 80 m 2 / g; preferably, the filler includes an inorganic filler and / or an organic filler; more preferably, the filler is a combination of the inorganic filler and the organic filler, and the weight ratio of the two is (0.9 to 1.1):(0.8 to 3.2); more preferably, the inorganic filler is selected from one or more of the group consisting of aluminum oxide, boron oxide, spherical silicon micropowder, matting powder, glass microbeads, calcium carbonate, talc powder, silica, and mica powder; more preferably, the organic filler is selected from one or more of the group consisting of polytetrafluoroethylene micropowder, polyimide powder, and silicon-containing aryl alkyne resin powder.

[0015] Further, the curing agent is selected from one or more of the group consisting of a modified aliphatic amine curing agent, a modified aromatic amine curing agent, a silicate curing agent, and an amino-based silane coupling agent; preferably, the curing agent is a combination of the modified aliphatic amine curing agent and the modified aromatic amine curing agent, and the weight ratio of the two is (70 to 80):(30 to 20).

[0016] Further, the modified aliphatic amine curing agent is selected from one or more of the group consisting of dicyandiamide, Mannich base-modified diethylenetriamine, Mannich base-modified triethylenetetramine, and epoxy-modified ethylenediamine; preferably, the modified aromatic amine curing agent is selected from one or more of the group consisting of epoxy-modified m-phenylenediamine, epoxy-modified m-xylylenediamine, epoxy-modified dimethylthiotoluenediamine, and acrylonitrile-modified dimethylthiotoluenediamine; preferably, the amino-based silane coupling agent is selected from one or more of the group consisting of 3-aminopropyltriethoxysilane, N-ethyl-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and γ-(phenylamino)propyltrimethoxysilane.

[0017] Further, the insulating adhesive composition further includes 5 to 10 parts by weight of a diluent; preferably, the diluent is selected from one or more of the group consisting of propylene oxide phenyl ether, neopentyl glycol diglycidyl ether, acetone, butanone, toluene, xylene, propylene glycol methyl ether acetate, dipropylene glycol methyl ether, and a divalent acid ester.

[0018] Further, the insulating adhesive composition further includes 0.1 to 0.5 parts by weight of an auxiliary agent; more preferably, the auxiliary agent is selected from one or more of the group consisting of a toughening agent, a coupling agent, an antioxidant, a leveling agent, and a surfactant.

[0019] To achieve the above object, another aspect of the present application further provides an insulating adhesive layer, which is obtained by sequentially mixing, coating and curing the above-mentioned insulating adhesive composition provided by the present application.

[0020] Still another aspect of the present application provides a back contact cell, which comprises a cell sheet and an insulating adhesive layer; the insulating adhesive layer is arranged on at least one side surface of the cell sheet; wherein the insulating adhesive layer is prepared by the above-mentioned method for preparing the insulating adhesive layer provided by the present application.

[0021] By using the technical scheme of the present application, an insulating adhesive composition is provided, wherein the base resin is the core component of the insulating adhesive composition, which determines the basic properties and curing characteristics of the insulating adhesive. The silicone resin has a unique Si-O bond structure, which endows it with extremely high thermal stability. By introducing the silicone resin with the above-mentioned specific weight average molecular weight into the insulating adhesive composition, on the one hand, the heat resistance of the insulating adhesive can be improved, the curing state of the insulating adhesive at high temperature can be maintained, and the tackiness of the insulating adhesive can be inhibited; on the other hand, the flowability and thixotropy of the insulating adhesive composition can be improved, the processing performance of the insulating adhesive composition can be improved, and the flexibility and wear resistance of the insulating adhesive can be improved, and the stability of the insulating adhesive under high temperature (≥ 280℃) and load conditions can be improved. The filler has a certain lubricating effect, and the introduction of the filler can improve the mechanical strength, wear resistance and heat resistance of the insulating adhesive, improve the insulating performance and environmental aging resistance of the insulating adhesive, so that the insulating adhesive can maintain good flowability while forming a dense, tough and excellent insulating adhesive film, and the anti-sticking ability of the insulating adhesive under high temperature and pressure conditions can be improved. The introduction of the curing agent can initiate the curing reaction of the base resin, so that the base resin and the additive form a solid three-dimensional network structure, the mechanical strength and thermal stability of the insulating adhesive are improved, and the stability of the insulating adhesive under long-term high temperature and load conditions is improved.

[0022] The use of the above-mentioned components in the above-mentioned specific range can play a synergistic effect, form a more stable and solid three-dimensional network structure, improve the mechanical strength and thermal stability of the insulating adhesive, and inhibit the tackiness of the insulating adhesive under long-term high temperature and load conditions, so as to improve the use safety of the back contact cell under high temperature (≥ 280℃) and load conditions, and promote the upgrading of photovoltaic technology and the large-scale industrialized production of high-efficiency components. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0024] As described in the background, the existing insulation glue has the problem of easy sticking under the condition of long time at high temperature and under load, and the problem of poor use safety of the back contact battery caused thereby. In order to solve the above technical problems, the first aspect of the present application provides an insulation glue composition, which comprises, by weight: 20-80 parts of a base resin, 2-10 parts of a curing agent, and 5-35 parts of an additive; wherein the additive is selected from an organic silicon resin and / or a filler, and the weight average molecular weight of the organic silicon resin is 5000-30000 g / mol.

[0025] In the above insulation glue composition provided by the present application, the base resin is the core component of the insulation glue composition, which determines the basic properties and curing characteristics of the insulation glue. The organic silicon resin in the additive has a unique Si-O bond structure, which gives it extremely high thermal stability. The introduction of the organic silicon resin with the above specific weight average molecular weight into the insulation glue composition can improve the heat resistance of the insulation glue, maintain the curing state of the insulation glue at high temperature, and inhibit its sticking; on the other hand, it can improve the flowability and thixotropy of the insulation glue composition, improve its processing performance, and also improve the flexibility and wear resistance of the insulation glue, and improve its stability under high temperature (≥280℃) and load conditions. The filler has a certain lubricating effect, and its introduction can improve the mechanical strength, wear resistance and heat resistance of the insulation glue, improve its insulation performance and environmental aging resistance, so that the insulation glue can maintain good flowability while forming a dense, tough and excellent insulation film, and improve its anti-sticking ability under high temperature and pressure conditions.

[0026] The introduction of the curing agent can initiate the curing reaction of the base resin, so that the base resin and the additive form a solid three-dimensional network structure, improve the mechanical strength and thermal stability of the insulation glue, and improve its stability under long time high temperature and load conditions.

[0027] Limiting the amount of each component in the above insulation glue composition provided by the present application to the above specific range can play a synergistic effect, form a more stable and solid three-dimensional network structure, improve the mechanical strength and thermal stability of the insulation glue, inhibit the use safety of the insulation under the condition of ≥280℃ and load, and promote the upgrading of photovoltaic technology and large-scale industrial production of high-efficiency components.

[0028] It should be noted that the weight average molecular weight of the organic silicone resin described above is measured by gel permeation chromatography. The specific test method is as follows: (1) weigh 3-10 mg of the organic silicone resin sample, dissolve the organic silicone resin sample in a specific solvent (such as tetrahydrofuran, N,N-dimethylformamide and chloroform, etc.), filter with a 0.45 μm or 0.22 μm organic filter membrane to remove insoluble substances or dust, and obtain a test sample; (2) use a gel permeation chromatograph (Agilent 1260 Infinity II GPC / SEC Solution) to detect the test sample, use tetrahydrofuran as the mobile phase, and the flow rate is 1 mL / min, obtain a GPC chromatogram, and calculate the weight average molecular weight of the organic silicone resin according to the GPC chromatogram.

[0029] In a preferred embodiment, the additive is a combination of the organic silicone resin and the filler, and the weight ratio of the organic silicone resin to the filler is (0.7-1.2):(1.9-2.3). Compared with other ranges, limiting the weight ratio of the organic silicone resin to the filler in the above range is beneficial to improve the physical and chemical adsorption and chemical bridging effect between the organic silicone resin and the matrix resin, and at the same time, is beneficial to improve the synergistic effect between the organic silicone resin and the filler, thereby being beneficial to improve the thermal stability, mechanical strength and wear resistance of the insulating adhesive, improve the stability of the insulating adhesive under high temperature and load conditions, inhibit the tackiness, and at the same time, is beneficial to improve the processability of the insulating adhesive composition.

[0030] In a preferred embodiment, the insulating adhesive composition includes, in terms of weight fraction: 20-80 parts of the matrix resin, 2-10 parts of the curing agent, 5-15 parts of the organic silicone resin and 10-20 parts of the filler. The components and their amounts in the insulating adhesive composition include but are not limited to the above ranges, and limiting them in the above ranges is beneficial to the curing reaction of the matrix resin under the action of the curing agent, and at the same time, is beneficial to introducing the organic silicone resin and the filler in a suitable amount, promoting the formation of a more stable three-dimensional network structure with the matrix resin, thereby being beneficial to improve the mechanical strength and thermal stability of the insulating adhesive, inhibiting the phenomenon of tackiness of the insulating adhesive under long-term high temperature and load conditions, and further being beneficial to improve the use safety of the back contact battery under high temperature and load conditions.

[0031] In order to promote the curing reaction of the matrix resin under the action of the curing agent, form a more stable three-dimensional network structure, and further improve the mechanical strength, flexibility, insulation performance and thermal stability of the insulating adhesive, in a preferred embodiment, the weight ratio of the matrix resin to the curing agent is (3-8):1.

[0032] In a preferred embodiment, the base resin includes, but is not limited to, one or more of the group consisting of epoxy resin, polysiloxane resin, polyurethane resin, polybutadiene resin and silicon-containing aryl alkyne resin. Compared with other types, the base resin of the above-mentioned type has excellent electrical insulation performance and high mechanical strength, and is conducive to forming a more stable three-dimensional network structure under the action of the curing agent, thereby being conducive to improving the insulation performance, mechanical strength and environmental aging resistance of the insulating adhesive, maintaining the curing state of the insulating adhesive under high temperature and load conditions, and inhibiting tackiness.

[0033] In order to further improve the curing degree of the base resin, increase the crosslinking density, further form a more compact and stable three-dimensional network structure, thereby further improving the thermal stability of the insulating adhesive and further inhibiting the occurrence of tackiness under high temperature and load conditions, in a preferred embodiment, the epoxy value of the epoxy resin is 0.25-0.55 eq / 100 g, and the weight average molecular weight is 200-400 g / mol.

[0034] In order to further improve the insulation performance, mechanical strength and environmental aging resistance of the insulating adhesive, further maintain the curing state of the insulating adhesive under high temperature and load conditions, and further inhibit tackiness, in a preferred embodiment, the epoxy resin includes, but is not limited to, one or more of the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin.

[0035] In order to further improve the insulation performance, mechanical strength and environmental aging resistance of the insulating adhesive, further maintain the curing state of the insulating adhesive under high temperature and load conditions, and inhibit tackiness, preferably, the weight average molecular weight of the polysiloxane resin is 10-50 thousand g / mol; preferably, the weight average molecular weight of the polyurethane resin is 80-200 thousand g / mol; preferably, the weight average molecular weight of the polybutadiene resin is 50-200 thousand g / mol; preferably, the weight average molecular weight of the silicon-containing aryl alkyne resin is 2-10 thousand g / mol, and the weight percentage of alkyne group in the silicon-containing aryl alkyne resin is 3.5-6 wt%.

[0036] The silicone resin has a unique Si-O bond structure, and the bond energy of the Si-O bond is much higher than the bond energy of the C-C bond in most organic materials. Even in a high-temperature environment, the silicone resin is not prone to molecular rupture or structural change, thereby facilitating the maintenance of the curing state of the insulating adhesive at high temperatures and inhibiting the tackiness thereof. In a preferred embodiment, the silicone resin includes, but is not limited to, one or more of the group consisting of epoxy-modified silicone resin, polymethylsilsesquioxane, and polyether-modified siloxane. The use of the above-mentioned types of silicone resin is beneficial in improving the heat resistance of the insulating adhesive, maintaining the curing state of the insulating adhesive at high temperatures and inhibiting the tackiness thereof, and improving the flowability and thixotropy of the insulating adhesive composition, thereby improving the processability thereof, and improving the flexibility and wear resistance of the insulating adhesive, thereby inhibiting the tackiness thereof under high-temperature and loaded conditions.

[0037] The epoxy-modified silicone resin contains epoxy groups, which are beneficial in improving the compatibility of the epoxy-modified silicone resin with the base resin, participating in the curing reaction, and improving the efficiency of the curing reaction, thereby facilitating the formation of a more compact and stable three-dimensional network structure, improving the thermal stability, mechanical strength, and environmental aging resistance of the insulating adhesive, and inhibiting the tackiness thereof under high-temperature and loaded conditions. The introduction of the epoxy groups is also beneficial in improving the insulating performance and chemical resistance of the insulating adhesive.

[0038] To further improve the compatibility of the epoxy-modified silicone resin with the base resin, form a more compact and stable three-dimensional network structure, and further improve the thermal stability, mechanical strength, and environmental aging resistance of the insulating adhesive, preferably, the functionality of the epoxy-modified silicone resin is 2-4.

[0039] To further improve the compatibility of the epoxy-modified silicone resin with the base resin, further improve the degree of the curing reaction, form a more stable three-dimensional network structure, further improve the thermal stability, mechanical strength, insulating performance, and chemical resistance of the insulating adhesive, and further inhibit the tackiness thereof under high-temperature and loaded conditions, preferably, the epoxy value of the epoxy-modified silicone resin is 0.05-0.2 eq / 100 g.

[0040] To further improve the compatibility of the epoxy-modified silicone resin with the base resin, further improve the thermal stability, mechanical strength, insulating performance, and environmental aging resistance of the insulating adhesive, and further inhibit the tackiness thereof under high-temperature and loaded conditions, more preferably, the epoxy-modified silicone resin includes, but is not limited to, polytetraoxepoxy cyclohexyl ethyl-2,4,6,8-tetramethyl cyclosiloxane and / or phenyl epoxy silicone resin.

[0041] In a preferred embodiment, the average particle size of the filler is 0.5-80 μm and the specific surface area is 0.1-80 m2 / g. The average particle size and the specific surface area of the filler include but are not limited to the above ranges, and limiting them within the above ranges is advantageous on the one hand for improving the dispersibility of the filler, improving the flowability and thixotropy of the insulating adhesive composition, and improving the processability thereof, thereby improving the uniformity of the insulating adhesive, and on the other hand for improving the interfacial adhesion strength between the filler and the matrix resin, improving the adhesion of the insulating adhesive to the surface of the substrate, and simultaneously improving the mechanical strength and environmental aging resistance of the insulating adhesive. 2 The average particle size and the specific surface area of the filler include but are not limited to the above ranges, and limiting them within the above ranges is advantageous on the one hand for improving the dispersibility of the filler, improving the flowability and thixotropy of the insulating adhesive composition, and improving the processability thereof, thereby improving the uniformity of the insulating adhesive, and on the other hand for improving the interfacial adhesion strength between the filler and the matrix resin, improving the adhesion of the insulating adhesive to the surface of the substrate, and simultaneously improving the mechanical strength and environmental aging resistance of the insulating adhesive.

[0042] It should be noted that the average particle size of the filler described above is measured by dynamic light scattering method. The specific surface area is measured by BET gas adsorption method.

[0043] The introduction of the inorganic filler can improve the mechanical strength, insulating property, wear resistance and heat resistance of the insulating adhesive; the introduction of the organic filler can improve the chemical stability of the insulating adhesive, improve the rheological properties and solder resist properties thereof, and the organic filler has more excellent slip properties, can reduce the surface tension of the insulating adhesive, and relieve the phenomenon of stickiness of the insulating adhesive under high temperature and load conditions. In a preferred embodiment, the filler includes an inorganic filler and / or an organic filler.

[0044] In a preferred embodiment, the filler is a combination of an inorganic filler and an organic filler, and the weight ratio of the two is (0.9-1.1):(0.8-3.2). The weight ratio of the inorganic filler and the organic filler includes but is not limited to the above ranges, and limiting them within the above ranges is advantageous for exerting the synergistic effect of the two, improving the mechanical strength, insulating property, wear resistance and heat resistance of the insulating adhesive, improving the rheological properties and solder resist properties thereof, and improving the stability of the insulating adhesive under high temperature and load conditions, and inhibiting the phenomenon of stickiness of the insulating adhesive.

[0045] In order to further improve the mechanical strength, insulating property, wear resistance and heat resistance of the insulating adhesive, and further inhibit the phenomenon of stickiness of the insulating adhesive under high temperature and load conditions, preferably, the inorganic filler includes but is not limited to one or more of the group consisting of alumina, boron oxide, spherical silicon micro powder, matting powder, glass microbeads, calcium carbonate, talc powder, silicon dioxide and mica powder.

[0046] In a preferred embodiment, the organic filler includes one or more of the group consisting of polytetrafluoroethylene micro-powder, polyimide powder and silicon-containing aryl alkyne resin powder. Compared with other kinds, the above-mentioned kinds of organic fillers have more excellent slip properties, which are beneficial to reduce the surface tension of the insulating glue and alleviate the phenomenon of stickiness of the insulating glue under high temperature and load conditions. On the other hand, the above-mentioned kinds of organic fillers are beneficial to improve the chemical stability of the insulating glue, improve the rheological properties and solder resist properties of the insulating glue, and improve the stability of the insulating glue under high temperature.

[0047] It should be noted that the silicon-containing aryl alkyne resin as the organic filler in the present application refers to a silicon-containing aryl alkyne resin powder which is pre-pulverized or made into microspheres.

[0048] The curing agent can catalyze the curing reaction of the base resin, so that the base resin changes from a liquid state to a solid state and forms a stable three-dimensional network structure. In a preferred embodiment, the curing agent includes one or more of the group consisting of modified aliphatic amine curing agent, modified aromatic amine curing agent, silicate curing agent and amino silane coupling agent. Compared with other kinds, the use of the above-mentioned kinds of curing agents can improve the efficiency of the curing reaction, which is beneficial to form a more compact and stable three-dimensional network structure, thereby improving the insulation performance, mechanical strength and environmental aging resistance of the insulating glue, maintaining the curing state of the insulating glue under high temperature and load conditions, and inhibiting stickiness.

[0049] In order to further improve the efficiency of the curing reaction, form a more compact and stable three-dimensional network structure, thereby further improving the insulation performance, mechanical strength and environmental aging resistance of the insulating glue, better maintaining the curing state of the insulating glue under high temperature and load conditions, and further inhibiting stickiness, in a preferred embodiment, the curing agent is a combination of modified aliphatic amine curing agent and modified aromatic amine curing agent, and the weight ratio of the two is (70-80):(30-20).

[0050] To further improve the efficiency of the curing reaction, form a more compact and stable three-dimensional network structure, thereby further improving the insulation performance, mechanical strength and environmental aging resistance of the insulating glue, better maintaining the curing state of the insulating glue under high temperature and load conditions, further inhibiting its tackiness, preferably, the modified aliphatic amine curing agent includes one or more of the group consisting of but not limited to dicyandiamide, mannich base modified diethylene triamine, mannich base modified triethylene tetramine and epoxy modified ethylenediamine; preferably, the modified aromatic amine curing agent includes one or more of the group consisting of but not limited to epoxy modified m-phenylenediamine, epoxy modified m-toluenediamine, epoxy modified dimethylthiophenyl toluene diamine and acrylonitrile modified dimethylthiophenyl toluene diamine; preferably, the amino silane coupling agent includes one or more of the group consisting of but not limited to 3-aminopropyl triethoxysilane, N-ethyl-γ-aminopropyl trimethoxysilane, N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane and γ-(phenylamino) propyl trimethoxysilane.

[0051] The introduction of the diluent can improve the viscosity of the insulating glue composition, improve its processability, and facilitate the formation of a uniform and smooth insulating glue layer. In a preferred embodiment, the insulating glue composition further includes 5-10 parts by weight of a diluent.

[0052] To further improve the viscosity of the insulating glue composition, further improve the processability of the insulating glue composition, and thereby form a more uniform and smooth insulating glue layer, preferably, the diluent includes one or more of the group consisting of but not limited to propylene oxide phenyl ether, neopentyl glycol diglycidyl ether, acetone, butanone, toluene, xylene, propylene glycol methyl ether acetate, dipropylene glycol methyl ether and divalent acid ester.

[0053] It should be noted that the divalent acid ester (DuPont designation DBE) in the present application is a mixture of three divalent acid esters, commonly known as nylon acid methyl ester, i.e. a mixture of dimethyl succinate, dimethyl glutarate and dimethyl adipate.

[0054] The introduction of the auxiliary can improve the comprehensive performance of the insulating glue, such as mechanical strength, toughness, weather resistance and adhesion to the substrate, etc. In a preferred embodiment, the insulating glue composition further includes 0.1-0.5 parts by weight of an auxiliary.

[0055] In a preferred embodiment, the adjuvant includes, but is not limited to, one or more of the group consisting of a toughening agent, a coupling agent, an antioxidant, a leveling agent, and a surfactant. The toughening agent can improve the elongation at break and impact resistance of the insulating glue, improve the toughness of the insulating glue under physical stress, and reduce the cracking or delamination phenomenon caused by external force. The coupling agent can improve the mutual combination between the additive (silicone resin and filler) and the base resin, enhance the mechanical strength and adhesion to the substrate of the insulating glue, reduce the risk of interlayer peeling, and improve the weather resistance and corrosion resistance of the insulating glue. The antioxidant can inhibit the aging of the insulating glue under ultraviolet light, oxygen, and a humid heat environment, ensure that the insulating glue still maintains good mechanical properties and electrical characteristics in harsh environments, and prolong its service life. The leveling agent and surfactant can improve the surface leveling and gloss of the insulating glue, reduce its surface tension, and alleviate the phenomenon of stickiness under high temperature and load conditions.

[0056] To further improve the elongation at break and impact resistance of the insulating glue, improve the toughness of the insulating glue under physical stress, and further reduce the cracking or delamination phenomenon caused by external force, preferably, the toughening agent includes, but is not limited to, one or more of the group consisting of nitrile rubber, liquid polysulfide rubber, polyether sulfone, and polyimide.

[0057] To further improve the mutual combination between the additive and the base resin, enhance the mechanical strength and adhesion to the substrate of the insulating glue, further reduce the risk of interlayer peeling, and further improve the weather resistance and corrosion resistance of the insulating glue, preferably, the coupling agent includes, but is not limited to, one or more of the group consisting of amino silane coupling agent, epoxy silane coupling agent, methacryloxy silane coupling agent, and titanate coupling agent.

[0058] To further improve the environmental aging resistance of the insulating glue, inhibit its aging under ultraviolet light, oxygen, and a humid heat environment, and thus further prolong its service life, preferably, the antioxidant includes, but is not limited to, a hindered phenol antioxidant and / or a phosphite antioxidant.

[0059] To further improve the surface leveling and gloss of the insulating glue, further reduce its surface tension, and alleviate the phenomenon of stickiness under high temperature and load conditions, preferably, the leveling agent includes, but is not limited to, one or more of the group consisting of a polyether-modified silicone leveling agent, a fluorocarbon leveling agent, an acrylic leveling agent, a glycol ether leveling agent, and an alcohol ester leveling agent; and the surfactant includes, but is not limited to, one or more of the group consisting of a fluorocarbon surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant.

[0060] The second aspect of the present application provides an insulating adhesive layer, which is obtained by sequentially mixing, coating and curing the above-mentioned insulating adhesive composition provided by the present application. The insulating adhesive layer prepared from the above-mentioned insulating adhesive composition provided by the present application has excellent insulating properties, mechanical strength, thermal stability and environmental aging resistance, and can be used in a back contact battery (BC battery) to improve the stability and safety of the BC battery.

[0061] The third aspect of the present application provides a preparation method of an insulating adhesive layer, which comprises: mixing the above-mentioned insulating adhesive composition provided by the present application to obtain an insulating adhesive; and coating the insulating adhesive on at least one side surface of a substrate to obtain the insulating adhesive layer after curing. By mixing the above-mentioned insulating adhesive composition provided by the present application, the insulating adhesive can be obtained, and at the same time, the organic silicon and / or filler additives can be introduced to interact with the matrix resin to form a more stable and solid three-dimensional network structure, thereby improving the mechanical strength and thermal stability of the insulating adhesive and inhibiting the phenomenon of stickiness of the insulating adhesive under long-time high-temperature and load conditions, so as to improve the safety of the back contact battery under high-temperature and load conditions. After coating the insulating adhesive on at least one side surface of the substrate and curing, the insulating adhesive layer can be obtained, which can be applied in the back contact battery to improve the stability and safety of the back contact battery.

[0062] In a preferred embodiment, the viscosity of the insulating adhesive is 10-20 Pa s, and the thixotropic index is 1.3-3.5. Compared with other ranges, limiting the viscosity and thixotropic index of the insulating adhesive within the above-mentioned ranges is beneficial to improving the processability of the insulating adhesive, facilitating the coating thereof, and thus being beneficial to obtaining an insulating adhesive layer with smooth and uniform surface.

[0063] It should be noted that the viscosity of the above-mentioned insulating adhesive is measured by a rotary viscometer (Shanghai Fangrui Instrument Co., Ltd., NDJ-5T) at a test temperature of 25°C. The thixotropic index is measured by a rotary rheometer (USA Thermo Fisher Scientific, HAAKE MARS iQ) through "three-stage shear test".

[0064] In order to remove the air introduced during the mixing process and the bubbles generated, and to improve the leveling property and thixotropy of the insulating adhesive, in a preferred embodiment, the insulating adhesive composition is subjected to a defoaming treatment after the mixing process to obtain the insulating adhesive.

[0065] In order to obtain an insulating adhesive layer with higher surface quality and further improve the production efficiency, in a preferred embodiment, the coating is performed by screen printing and / or blade coating.

[0066] In a preferred embodiment, the curing temperature is 180-200°C and the curing time is 10-15 min. The curing temperature and time include but are not limited to the above ranges, and limiting them within the above ranges is beneficial to improving the efficiency and effect of curing, and is beneficial to inhibiting side reactions or decomposition caused by excessively high temperature, thereby being beneficial to ensuring that the insulation glue with more excellent performance is obtained.

[0067] The preparation method of the above-mentioned insulation glue layer provided by the present application is suitable for substrates of various materials. Preferably, the material of the substrate includes but is not limited to a silicon wafer (including a cell wafer), glass, polyethylene terephthalate (PET), or polypropylene (PP).

[0068] The fourth aspect of the present application also provides a back contact cell, which comprises a cell wafer and an insulation glue layer; the insulation glue layer is arranged on at least one side surface of the cell wafer; and the insulation glue layer is prepared by using the above-mentioned preparation method of the insulation glue layer provided by the present application. The insulation glue layer prepared by using the above-mentioned preparation method of the insulation glue layer provided by the present application has excellent insulation performance, mechanical strength, thermal stability, and environmental aging resistance, and it does not stick for 3.5 h under the condition of 280°C and a load of 7 kg, so that when it is applied in a back contact cell, it can effectively insulate the positive electrode and the negative electrode of the back contact cell, inhibit the formation of a short circuit of an electric current in the back contact cell, and thereby improve the stability and use safety of the back contact cell.

[0069] The present application will be further described in detail below in combination with specific examples, which cannot be understood as limiting the scope of the present application.

[0070] Example 1

[0071] A preparation method of an insulation glue, comprising the following steps:

[0072] (1) Preparing each component raw material for standby, and the total weight fraction of each component is 50 parts, including 30 parts of a base resin, 5 parts of a curing agent, and 15 parts of an organic silicon resin; wherein the base resin is a bisphenol A type epoxy resin (weight average molecular weight is 300 g / mol, and an epoxy value is 0.25 eq / 100 g), the curing agent is dicyandiamide (CAS number: 461-58-5), and the organic silicon resin is polytetraoxepoxy cyclohexyl ethyl-2, 4, 6, 8-tetramethyl cyclo tetra siloxane (weight average molecular weight is 20000 g / mol, functionality is 4, and an epoxy value is 0.15 eq / 100 g);

[0073] (2) Mixing the above-mentioned base resin and the additive organic silicon resin, and transferring all of them to a debubbling machine for debubbling treatment, and then adding the curing agent, and obtaining the insulation glue after uniform stirring; wherein the viscosity of the insulation glue is 20 Pa s, and the thixotropic index is 3.2.

[0074] Example 2

[0075] The difference from Example 1 is that in step (1), the silicone resin is replaced with equal amount of phenyl epoxy silicone oil (weight average molecular weight of 10000 g / mol, functionality of 3, epoxy value of 0.1 eq / 100 g) instead of polytetraepoxy cyclohexyl ethyl-2,4,6,8-tetramethylcyclotetrasiloxane in Example 1; the rest of the steps are the same as Example 1.

[0076] Example 3

[0077] The difference from Example 1 is that in step (1), the silicone resin is replaced with equal amount of polymethylsilsesquioxane (weight average molecular weight of 5000 g / mol) instead of polytetraepoxy cyclohexyl ethyl-2,4,6,8-tetramethylcyclotetrasiloxane in Example 1; the rest of the steps are the same as Example 1.

[0078] Example 4

[0079] The difference from Example 1 is that in step (1), the silicone resin is replaced with equal amount of side-chain type polyether modified siloxane (weight average molecular weight of 6500 g / mol) instead of polytetraepoxy cyclohexyl ethyl-2,4,6,8-tetramethylcyclotetrasiloxane in Example 1; the rest of the steps are the same as Example 1.

[0080] Example 5

[0081] The difference from Example 1 is that in step (1), the matrix resin is replaced with equal amount of sila-arylacetylene resin (weight average molecular weight of 2350 g / mol, wherein the weight percentage content of acetylene group is 5wt%) instead of bisphenol A type epoxy resin in Example 1; the silicone resin is replaced with equal amount of epoxy modified silicone resin (weight average molecular weight of 5000 g / mol, functionality of 3, epoxy value of 0.18 eq / 100 g) instead of polytetraepoxy cyclohexyl ethyl-2,4,6,8-tetramethylcyclotetrasiloxane in Example 1; the rest of the steps are the same as Example 1.

[0082] Example 6

[0083] The difference from Example 1 is that in step (1), no silicone resin is added, and the total weight fraction of each component is 100 parts, including: 70 parts of matrix resin, 10 parts of curing agent and 20 parts of filler; wherein the types of matrix resin and curing agent are the same as Example 1, and the filler is polytetrafluoroethylene micro powder (average particle size of 5 μm, specific surface area of 8.2 m 2 / g); the rest of the steps are the same as Example 1.

[0084] Example 7

[0085] The difference from Example 1 is that no silicone resin is added in step (1), and the total weight fraction of each component is 100 parts, including 70 parts of matrix resin, 10 parts of curing agent and 20 parts of filler; wherein the types of matrix resin and curing agent are the same as those in Example 1, and the filler is fumed nano-alumina (average particle size is 0.5 μm, specific surface area is 80 m 2 / g); the remaining steps are the same as those in Example 1.

[0086] Example 8

[0087] The difference from Example 1 is that no silicone resin is added in step (1), and the total weight fraction of each component is 100 parts, including 70 parts of matrix resin, 10 parts of curing agent and 20 parts of filler; wherein the types of matrix resin and curing agent are the same as those in Example 1, and the filler is nano-boron oxide (average particle size is 0.5 μm, specific surface area is 61 m 2 / g); the remaining steps are the same as those in Example 1.

[0088] Example 9

[0089] The difference from Example 1 is that no silicone resin is added in step (1), and the total weight fraction of each component is 100 parts, including 70 parts of matrix resin, 10 parts of curing agent and 20 parts of filler; wherein the types of matrix resin and curing agent are the same as those in Example 1, and the filler is polyimide powder (average particle size is 50 μm, specific surface area is 3.6 m 2 / g); the remaining steps are the same as those in Example 1.

[0090] Example 10

[0091] The difference from Example 1 is that no silicone resin is added in step (1), and the total weight fraction of each component is 100 parts, including 70 parts of matrix resin, 10 parts of curing agent and 20 parts of filler; wherein the types of matrix resin and curing agent are the same as those in Example 1, and the filler is glass microbeads (average particle size is 80 μm, specific surface area is 0.28 m 2 / g); the remaining steps are the same as those in Example 1.

[0092] Example 11

[0093] The difference from Example 1 is that in step (1), an equal amount of a combination of silicone resin and filler is used to replace the silicone resin, wherein the weight ratio of silicone resin to filler is 0.7:2.3, the silicone resin is an epoxy-modified silicone resin (weight average molecular weight is 5000 g / mol, functionality is 3, epoxy value is 0.18 eq / 100 g), and the filler is polytetrafluoroethylene micro powder (average particle size is 5 μm, specific surface area is 8.2 m 2 / g); the remaining steps are the same as those in Example 1.

[0094] Example 12

[0095] The difference from Example 1 is that in step (1), the same amount of a composition of silicone resin and filler is used to replace the silicone resin, wherein the weight ratio of the silicone resin to the filler is 1.2:1.9, the silicone resin is an epoxy-modified silicone resin (weight average molecular weight is 5000 g / mol, functionality is 3, and epoxy value is 0.18 eq / 100 g), and the filler is polytetrafluoroethylene micro powder (average particle size is 5 μm, and specific surface area is 8.2 m 2 / g); and the remaining steps are the same as those in Example 1.

[0096] Example 13

[0097] The difference from Example 1 is that in step (1), the same amount of a composition of silicone resin and filler is used to replace the silicone resin, wherein the weight ratio of the silicone resin to the filler is 1:1, the silicone resin is an epoxy-modified silicone resin (weight average molecular weight is 5000 g / mol, functionality is 3, and epoxy value is 0.18 eq / 100 g), and the filler is polytetrafluoroethylene micro powder (average particle size is 5 μm, and specific surface area is 8.2 m 2 / g); and the remaining steps are the same as those in Example 1.

[0098] Example 14

[0099] The difference from Example 1 is that in step (1), the total weight fraction of the components is 50 parts, including 35 parts of the matrix resin, 10 parts of the curing agent, and 5 parts of the silicone resin; and the remaining steps are the same as those in Example 1.

[0100] Example 15

[0101] The difference from Example 1 is that in step (1), no silicone resin is added, and the total weight fraction of the components is 100 parts, including 80 parts of the matrix resin, 10 parts of the curing agent, and 10 parts of the filler; wherein the filler is polytetrafluoroethylene micro powder (average particle size is 5 μm, and specific surface area is 8.2 m 2 / g); and the remaining steps are the same as those in Example 1.

[0102] Example 16

[0103] The difference from Example 1 is that in step (1), the total weight fraction of the components is 50 parts, including 30 parts of the matrix resin, 2 parts of the curing agent, 12.5 parts of the silicone resin, 5 parts of the diluent, and 0.5 parts of the auxiliary agent, wherein the diluent is propylene glycol methyl ether acetate, and the auxiliary agent is silane coupling agent γ-glycidoxypropyltrimethoxysilane (KH560); and the remaining steps are the same as those in Example 1.

[0104] Example 17

[0105] The difference from Example 1 is that in step (1), the total weight parts of each component is 50 parts, including 30 parts of base resin, 2 parts of curing agent, 14 parts of silicone resin, 3.2 parts of diluent and 0.8 parts of auxiliary agent, wherein the diluent is propylene glycol methyl ether acetate and the auxiliary agent is silane coupling agent KH560, and the remaining steps are the same as those of Example 1.

[0106] Comparative Example 1

[0107] The difference from Example 1 is that in step (1), no silicone resin is introduced, and the total weight parts of each component is 50 parts, including 46 parts of base resin and 4 parts of curing agent, and the remaining steps are the same as those of Example 1.

[0108] Comparative Example 2

[0109] The difference from Example 1 is that in step (1), the total weight parts of each component is 50 parts, including 10 parts of base resin and 1 part of curing agent and 39 parts of silicone resin, and the remaining steps are the same as those of Example 1.

[0110] The insulating adhesive wire screen prepared in the above Examples 1 to 17 and Comparative Examples 1 and 2 is printed on the front of a back contact cell (Aixtron, black hole series), and then cured at 200℃ for 5min to obtain an insulating adhesive layer with a thickness of 10μm.

[0111] The insulating adhesive layer obtained in the above Examples 1 to 17 and Comparative Examples 1 and 2 is tested for the following properties:

[0112] (1) The side surfaces of the insulating adhesive layers of two cell pieces with the same insulating adhesive layer are contacted with each other to obtain a sample to be tested for testing the double-side tackiness, and the cell piece with the insulating adhesive layer on the front is placed opposite to the cell piece without the insulating adhesive layer on the front to obtain a sample to be tested for testing the single-side tackiness;

[0113] The testing conditions for the tackiness of the insulating adhesive layer are as follows: the sample to be tested is placed in a vacuum drying oven at 280℃, and a load of 7kg is continuously applied to the sample to be tested, and after 3.5h, the sample to be tested is taken out, an adhesive tape is stuck to the side surface of the cell piece away from the insulating adhesive layer, and the two cell pieces are shaken gently by hand, and whether the two cell pieces can be separated is observed, if yes, the insulating adhesive layer has no tackiness, and if not, the insulating adhesive layer has tackiness;

[0114] (2) Test the initial peeling force: coat the insulating adhesive on one side surface of the battery piece, and cure at 200℃ for 5 min to obtain an insulating adhesive layer with a thickness of 10 μm; stack the back layer back plate, the back layer EVA adhesive film, the back layer EVA (ethylene-vinyl acetate copolymer) adhesive film, the release paper, the battery piece with the insulating adhesive layer, the front layer EVA adhesive film and the front layer glass in sequence, wherein the side surface of the insulating adhesive layer of the battery piece with the insulating adhesive layer is in contact with the release paper to obtain a laminated piece; the structure of the laminated piece comprises the back layer back plate / back layer EVA adhesive film / release paper / battery piece with insulating adhesive layer / front layer EVA adhesive film / front layer glass which are sequentially stacked;

[0115] Place the laminated piece in a laminator, and laminate at 145℃ for 15 min, then take it out after cooling, cut it into a sample with a width of 10 mm and a length of 40 mm, then peel it apart along the long edge direction, and the peeling distance is 20 mm to obtain a sample to be tested, and then use a universal material testing machine to test the peeling force, and the test conditions are: T-type peeling, peeling rate is 200 mm / min, and the average value of the peeling force in the effective peeling length (i.e. excluding the distance peeled before testing) is calculated, which is the initial peeling force; when the initial peeling force is greater than or equal to 30 N, it is considered to be qualified;

[0116] (3) Use a high-temperature electric welding pen (temperature is 365℃) to draw a line on the insulating adhesive layer, and then observe under a microscope whether the insulating adhesive is broken, if not, it indicates that the insulating adhesive layer has good solder resistance.

[0117] The test results are shown in Table 1.

[0118] Table 1

[0119]

[0120] As can be seen from Table 1, except for Examples 3, 5 and 6, the rest of the examples all have the phenomenon of double-sided tackiness, which is because the double-sided tackiness test is to contact the insulating adhesive layer with the insulating adhesive layer, which has higher requirements for tackiness, and the insulating adhesive layer is prone to adhesion, so that two battery pieces cannot be separated, however, Examples 1 to 17 in the present application do not have the phenomenon of single-sided tackiness, which indicates that compared with the existing insulating adhesive layer, the above-mentioned insulating adhesive layer provided by the present application has better heat resistance, which can inhibit the tackiness of the insulating adhesive layer at high temperature (≥ 280℃) to a certain extent. In addition, the initial peeling force and solder resistance of the insulating adhesive layer prepared by all the examples of the present application are better than those of the comparative examples, which also indicates that the insulating adhesive layer prepared by the present application has good adhesion and heat resistance.

[0121] From the above description, it can be seen that the above-mentioned examples of the present application achieve the following technical effects:

[0122] The silicone resin of the specific kind described above is introduced into the insulating adhesive composition, which can improve the heat resistance of the insulating adhesive, maintain the curing state of the insulating adhesive at high temperature (≥ 280℃), and inhibit the tackiness thereof; meanwhile, it can also improve the flowability and thixotropy of the insulating adhesive composition, and improve the processing performance thereof, thereby improving the flexibility and wear resistance of the insulating adhesive, and improving the stability thereof under high temperature and load conditions. The introduction of the filler can not only improve the mechanical strength, wear resistance and heat resistance of the insulating adhesive, and improve the insulating performance and environmental aging resistance thereof, but also can play a certain smoothing effect, and improve the anti-sticking ability of the insulating adhesive under high temperature and pressure conditions. The introduction of the curing agent can initiate the curing reaction of the base resin, and make the base resin and the additive form a solid three-dimensional network structure, thereby improving the mechanical strength and thermal stability of the insulating adhesive, and improving the stability thereof under long-time high temperature and load conditions.

[0123] Compared with other ranges, the use amount of each component in the insulating adhesive composition is limited in the specific range described above, which can play a synergistic effect, form a more stable and solid three-dimensional network structure, improve the mechanical strength and thermal stability of the insulating adhesive, and inhibit the tackiness of the insulating adhesive under long-time high temperature and load conditions, thereby improving the use safety of the back contact battery under high temperature and load conditions, and promoting the upgrading of photovoltaic technology and the large-scale industrialized production of high-efficiency components.

[0124] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the terms thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that described herein.

[0125] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An insulating adhesive composition, characterized in that, The insulating adhesive composition comprises, by weight, 20-80 parts of a base resin, 2-10 parts of a curing agent, and 5-35 parts of an additive; wherein the additive is selected from silicone resins and / or fillers; when the additive includes silicone resin, the weight-average molecular weight of the silicone resin is 5000-30000 g / mol.

2. The insulating adhesive composition according to claim 1, characterized in that, The additive is a combination of the silicone resin and the filler, and the weight ratio of the silicone resin to the filler is (0.7-1.2):(1.9-2.3). Preferably, the insulating adhesive composition comprises, by weight, 20-80 parts of the matrix resin, 2-10 parts of the curing agent, 5-15 parts of the silicone resin and 10-20 parts of the filler; Preferably, the weight ratio of the matrix resin to the curing agent is (3-8):

1.

3. The insulating adhesive composition according to claim 1 or 2, characterized in that, The matrix resin is selected from one or more of the group consisting of epoxy resin, polysiloxane resin, polyurethane resin, polybutadiene resin and silane-containing resin; Preferably, the epoxy resin has an epoxy value of 0.25 to 0.55 eq / 100g and a weight-average molecular weight of 200 to 400 g / mol; more preferably, the epoxy resin is selected from one or more of the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin and alicyclic epoxy resin. Preferably, the weight-average molecular weight of the polysiloxane resin is 10,000 to 50,000 g / mol; Preferably, the weight-average molecular weight of the polyurethane resin is 80,000 to 200,000 g / mol; Preferably, the weight-average molecular weight of the polybutadiene resin is 50,000 to 200,000 g / mol; Preferably, the weight-average molecular weight of the silicone-aryynylene resin is 2000-10000 g / mol, and the alkynyl group accounts for 3.5-6 wt% of the weight of the silicone-aryynylene resin.

4. The insulating adhesive composition according to any one of claims 1 to 3, characterized in that, The silicone resin is selected from one or more of the group consisting of epoxy-modified silicone resin, polymethylsilsesquioxane, and polyether-modified silicone resin. Preferably, the functionality of the epoxy-modified silicone resin is 2 to 4; Preferably, the epoxy value of the epoxy-modified silicone resin is 0.05 to 0.2 eq / 100g.

5. The insulating adhesive composition according to any one of claims 1 to 3, characterized in that, The filler has an average particle size of 0.5–80 μm and a specific surface area of ​​0.1–80 m². 2 / g; Preferably, the filler comprises inorganic fillers and / or organic fillers; More preferably, the packing material is a combination of inorganic and organic packing materials, and the weight ratio of the two is (0.9-1.1):(0.8-3.2). More preferably, the inorganic filler is selected from one or more of the group consisting of alumina, boron oxide, spherical silica powder, matting powder, glass microspheres, calcium carbonate, talc, silica and mica powder; More preferably, the organic filler is selected from one or more of the group consisting of polytetrafluoroethylene micro powder, polyimide powder, and silicone-containing aromatic resin powder.

6. The insulating adhesive composition according to claim 1 or 2, characterized in that, The curing agent is selected from one or more of the group consisting of modified aliphatic amine curing agents, modified aromatic amine curing agents, silicate ester curing agents, and amino silane coupling agents; Preferably, the curing agent is a combination of modified aliphatic amine curing agent and modified aromatic amine curing agent, and the weight ratio of the two is (70-80):(30-20).

7. The insulating adhesive composition according to claim 6, characterized in that, The modified aliphatic amine curing agent is selected from one or more of the group consisting of dicyandiamide, Mannich base modified diethylenetriamine, Mannich base modified triethylenetetramine, and epoxy modified ethylenediamine. Preferably, the modified aromatic amine curing agent is selected from one or more of the group consisting of epoxy-modified m-phenylenediamine, epoxy-modified m-phenylenediamine, epoxy-modified dimethyl thiotoluene diamine, and acrylonitrile-modified dimethyl thiotoluene diamine; Preferably, the amino-based silane coupling agent is selected from one or more of the group consisting of 3-aminopropyltriethoxysilane, N-ethyl-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and γ-(phenylamino)propyltrimethoxysilane.

8. The insulating adhesive composition according to any one of claims 1 to 7, characterized in that, The insulating adhesive composition further includes 5 to 10 parts by weight of diluent; Preferably, the diluent is selected from one or more of the group consisting of propylene oxide phenyl ether, neopentyl glycol diglycidyl ether, acetone, butanone, toluene, xylene, propylene glycol methyl ether acetate, dipropylene glycol methyl ether, and divalent esters; Preferably, the insulating adhesive composition further includes 0.1 to 0.5 parts by weight of additives; More preferably, the additive is selected from one or more of the group consisting of toughening agents, coupling agents, antioxidants, leveling agents and surfactants.

9. An insulating adhesive layer, characterized in that, The insulating adhesive layer is obtained by sequentially mixing, coating and curing the insulating adhesive composition according to any one of claims 1 to 8.

10. A back-contact battery, characterized in that, The back contact battery includes a battery cell and an insulating adhesive layer; the insulating adhesive layer is disposed on at least one surface of the battery cell; the insulating adhesive layer is selected from the insulating adhesive layer of claim 9.

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