Battery module acquisition and integration assembly having flame-retardant characteristics, and preparation method therefor

Abstract

The present invention belongs to the technical field of new energy power battery packs and energy storage. Disclosed are a battery module acquisition and integration assembly having flame-retardant characteristics, and a preparation method therefor. The acquisition and integration assembly comprises a PET base film coated with a flame-retardant adhesive layer, and an acquisition circuit component hot-press encapsulated on a side of the PET base film flame-retardant adhesive layer. The flame-retardant adhesive layer is composed of the following constituents in parts by weight: 20-80 parts of a thermosetting resin, 5-20 parts of a curing agent, and 20-80 parts of a flame retardant. The acquisition circuit component is connected to each conductive busbar by means of a FPC, FFC, FDC or FCC, and can be affixed to the PET base film coated with a flame-retardant adhesive layer, and then integrally cured and formed by means of hot-press encapsulation. In the present invention, the addition of a high-grade temperature resistance flame-retardant layer to the acquisition and integration assembly avoids the risk of spontaneous combustion of a battery cell caused by overlapping and sparking of a circuit after a protective adhesive film on the surface of a circuit board is melted through due to the ejection of high-temperature gas during thermal runaway of the battery cell.

Description

Battery module collection integrated assembly with flame retardant characteristics and preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the field of new energy power battery packs and energy storage technologies, and specifically relates to a battery module collection integrated assembly with flame retardant characteristics and a preparation method thereof. BACKGROUND

[0002] The collection integrated busbar (CCS or IBB) is a highly integrated battery signal collection (such as temperature collection, pressure collection, etc.) and management system. The existing CCS is mainly assembled by an FPC assembly and a conductive bus connecting aluminum bar (aluminum bar) through a certain mode. The FPC assembly includes an FPC board, a connector, a nickel sheet, an NTC resistor, etc. Shan summarizes that all the components are connected by welding, and then assembled by using a black film for hot pressing, so as to make it a whole component, thereby improving the reliability of the whole product.

[0003] However, since the working conditions of the battery pack are relatively complex, there is no mature technology in the current industrial technical field to completely avoid the thermal runaway of the battery cell. When the battery cell appears thermal runaway, the explosion-proof valve will start to work to release the high-temperature and high-pressure gas in the battery cell. The temperature of this high-temperature and high-pressure gas is often above 500 DEG C. Although the CCS products on the market are all made of flame-retardant materials, the organic adhesive film covering the surface of the collection circuit (such as FPC) has a temperature resistance level of only 150 DEG C (PET) or 250 DEG C (PI). When encountering a high temperature of 500 DEG C, softening, fluidization and shrinkage deformation will occur, which will cause the copper line of the collection circuit to be fixed poorly. Once the copper line is overlapped, a short circuit will occur, causing uncontrollable severe combustion of the entire battery pack, resulting in significant property and personal safety losses.

[0004] In our previous patent CN116505204A, a flame-retardant sheet layer such as a mica sheet, a flexible ceramic sheet, a Mylar sheet or a fireproof paper is adhered to the adhesive film layer to achieve flame-retardant effect and improve the stability and safety of the circuit. However, the way of adhering the flame-retardant sheet layer increases the assembly process of the battery pack, and the adhesion stability of the flame-retardant sheet layer is poor, and the close adhesion with the collection circuit assembly is also poor. The flame-retardant reliability needs to be further improved. SUMMARY

[0005] In view of the defects and shortcomings of the prior art, the primary object of the present application is to provide a battery module collection integrated assembly with flame-retardant properties. The battery module collection integrated assembly of the present application uses a PET base film coated with a flame-retardant adhesive to fix the collection circuit assembly, and the heat-insulating flame-retardant layer is tightly attached to the collection circuit, so that the assembly does not delaminate when some battery cells are in thermal runaway, high-temperature gas does not come into contact with the collection circuit to cause short-circuiting and sparking risks, and the thermal runaway does not spread.

[0006] Another object of the present application is to provide a preparation method of a battery module collection integrated assembly with flame-retardant properties.

[0007] The object of the present application is achieved by the following technical solutions.

[0008] A battery module collection integrated assembly with flame-retardant properties comprises a PET base film coated with a flame-retardant adhesive layer and a collection circuit assembly heat-pressed and packaged on one side of the flame-retardant adhesive layer of the PET base film. The flame-retardant adhesive layer comprises the following components by weight: 20-80 parts of a heat-curable resin, 5-20 parts of a curing agent, and 20-80 parts of a flame-retardant agent.

[0009] Further, the thickness of the PET base film is 0.03-0.5 mm, and the thickness of the flame-retardant adhesive layer is 0.1-1 mm.

[0010] Further, the collection circuit assembly comprises a conductive circuit and a plurality of conductive bus bars connected to the conductive circuit.

[0011] Further, the conductive circuit is an FPC (Flexible Printed Circuit), the FPC is individually connected to each conductive bus bar through a nickel sheet relay; or the conductive circuit is an FFC (Flexible Flat Cable), the FFC is individually connected to each conductive bus bar through a nickel sheet relay; or the conductive circuit is an FDC (Flexible Die cutting Circuit), the FDC is individually connected to each conductive bus bar through a nickel sheet relay or the FDC is directly connected to each conductive bus bar; or the conductive circuit is an FCC, that is, an FFC circuit is individually connected to each conductive bus bar through an FPC small plate relay.

[0012] Further, the heat-curable resin is one or more of nitrile rubber, epoxy resin, polyester resin, acrylic resin, and polyurethane resin.

[0013] Further, the curing agent is one or more of 4,4'-diamino diphenyl sulfone, dicyandiamide, acid anhydride, imidazole, HDI, TDI, and melamine.

[0014] Further, the flame retardant is one or more of aluminum diethylphosphinate, hexaphenoxycyclotriphosphazene, and ammonium polyphosphate.

[0015] In addition, to further improve the flame-retardant and heat-insulating effect of the collection integrated assembly, a flame-retardant sheet layer such as a mica sheet, mica paper, flexible ceramic, fireproof paper, aerogel, or ceramic sheet can be additionally arranged between the PET base film and the collection circuit assembly. The flame-retardant sheet layer and the collection circuit assembly and the flame-retardant sheet layer and the PET base film are coated with the flame-retardant adhesive layer.

[0016] The collection circuit assembly can be punched to avoid the explosion-proof valve part of the battery cell, or can not be punched. When there is a punch, the flame-retardant adhesive layer is arranged or not arranged on the side of the collection circuit assembly facing the battery cell. When there is no punch, the flame-retardant adhesive layer is arranged on the side of the collection circuit assembly facing the battery cell.

[0017] The conventional structures not described in the present application can refer to the description in the previous patent CN 116505204 A.

[0018] A preparation method of a battery module collection integrated assembly with flame-retardant properties, comprising the following preparation steps:

[0019] (1) terephthalic acid, isocyanate acrylate ethyl ester, and an organic tin catalyst are added to an ethyl acetate solvent for heating and stirring reaction to obtain a crosslinking monomer solution;

[0020] (2) the crosslinking monomer solution obtained in step (1) is mixed with acrylic acid monomer and acrylate monomer, then diluted with an ethyl acetate solvent, deoxygenated with nitrogen, and then heated for copolymerization reaction after adding an initiator to obtain a modified acrylic acid resin solution;

[0021] (3) the modified acrylic acid resin solution obtained in step (2) is mixed with an epoxy resin and then heated for reaction, and after cooling to room temperature, a flame retardant and a curing agent are added and uniformly mixed to obtain a mixed glue solution;

[0022] (4) the mixed glue solution obtained in step (3) is coated on a PET base film, and then a collection circuit assembly is pasted and fixed, and the whole is heat-pressed and packaged and cured to obtain a battery module collection integrated assembly with flame-retardant properties.

[0023] Further, in step (1), the molar ratio of terephthalic acid to isocyanate acrylate ethyl ester is 1:2; the organic tin catalyst is dibutyltin dilaurate; and the heating and stirring reaction is carried out at a temperature of 60-90°C.

[0024] Further, the acrylic acid monomer in step (2) is a mixture of one or both of acrylic acid and methacrylic acid; the acrylic ester monomer is at least one of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate, and isooctyl methacrylate.

[0025] Further, the mass ratio of the crosslinking monomer to the acrylic acid monomer and the acrylic ester monomer in the crosslinking monomer solution in step (2) is 0.05-0.3:1-2:1-2.

[0026] Further, the amount of the ethyl acetate solvent added in step (2) is such that the solid content of the reaction system is 30%-50%; the initiator is azobisisobutyronitrile or azobisisoheptyl nitrile; and the temperature for the copolymerization reaction is 60-80℃.

[0027] Further, the epoxy resin in step (3) is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin; and the mass ratio of the modified acrylic resin to the epoxy resin in the modified acrylic resin solution is 2-4:1-2.

[0028] Further, the temperature for the heating reaction in step (3) is 40-60℃, and the time for the heating reaction is 0.5-3h. The heating reaction grafts the epoxy groups of the epoxy resin to the acrylic acid segments in the modified acrylic resin, thereby improving the compatibility and stability of the mixed sizing solution and enhancing the bonding and curing effects of the flame-retardant sizing.

[0029] Further, the PET base film to which the mixed sizing solution is applied in step (4) is prepared by a roll-to-roll process.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] (1) The specific flame-retardant sizing layer used in the present application realizes heat insulation and flame retardation of the collection circuit assembly. Compared with the conventional flame-retardant sheet layer with high-temperature resistance and insulation, the flame-retardant sizing layer has the advantage of strong adhesion to the collection circuit assembly. The heat insulation and flame-retardant layer is closely attached to the collection circuit, so that the assembly does not delaminate when some battery cells are in thermal runaway, and the high-temperature gas does not contact the collection circuit to cause a short-circuiting and sparking risk, and the thermal runaway does not spread.

[0032] (2) The PET base film to which the flame-retardant sizing layer is applied can be prepared by a roll-to-roll process. Compared with the conventional scheme of combining the flame-retardant sheet layer with high-temperature resistance and insulation, the flame-retardant sizing layer has the advantages of high reliability, high production efficiency, and low cost.

[0033] (3) The application further adopts a modified acrylic resin and an epoxy resin thermosetting resin system, which has good thermosetting effect and bonding effect; the crosslinking monomer obtained by reacting terephthalic acid and isocyanate acrylate ethyl ester is used for copolymerization and crosslinking modification of the acrylic resin, which can improve the cohesive strength of the resin and the bonding force with the PET base film, improve the bonding strength of the flame-retardant adhesive film layer and the PET base film and the collection circuit assembly, realize the pasting and composite of the collection circuit assembly under the condition of high flame-retardant additive amount, and finally improve the structural stability and flame-retardant effect of the hot-pressed collection circuit assembly. DETAILED DESCRIPTION

[0034] The application will be further described in detail below in combination with examples, but the embodiments of the application are not limited thereto.

[0035] Example 1

[0036] A battery module collection integrated assembly with flame-retardant properties comprises a PET base film coated with a flame-retardant adhesive layer and a collection circuit assembly hot-pressed on one side of the flame-retardant adhesive layer of the PET base film. The battery module collection integrated assembly with flame-retardant properties is prepared by the following method.

[0037] The flame-retardant adhesive is coated on a PET base film with a thickness of 0.2 mm, the thickness of the flame-retardant adhesive coating is 0.5 mm, and then the collection circuit assembly is pasted and fixed, and the whole is hot-pressed and packaged and cured to obtain the battery module collection integrated assembly with flame-retardant properties. The collection circuit assembly comprises an FPC conductive circuit and a plurality of conductive bus connection rows, and the FPC conductive circuit is connected to each conductive bus connection row through a nickel sheet.

[0038] The flame-retardant adhesive comprises 60 parts (calculated by solid content) of bisphenol A type epoxy resin (E-44), 10 parts of curing agent 4,4'-diamino diphenyl sulfone, and 60 parts of flame-retardant agent aluminum diethyl phosphinate. The preparation method of the flame-retardant adhesive is as follows: the raw materials are weighed according to the weight parts, and the bisphenol A type epoxy resin, the curing agent 4,4'-diamino diphenyl sulfone and the flame-retardant agent aluminum diethyl phosphinate are stirred and mixed uniformly to obtain the flame-retardant adhesive.

[0039] Example 2

[0040] A battery module collection integrated assembly with flame-retardant properties comprises a PET base film coated with a flame-retardant adhesive layer and a collection circuit assembly hot-pressed on one side of the flame-retardant adhesive layer of the PET base film. The battery module collection integrated assembly with flame-retardant properties is prepared by the following method.

[0041] The fire-retardant adhesive is coated on a PET base film with a thickness of 0.3 mm, the thickness of the fire-retardant adhesive coating is 0.6 mm, then the battery module collection integrated assembly with fire-retardant property is obtained by fixing the collection circuit assembly and then heat-pressing and packaging and curing. The collection circuit assembly comprises an FFC conductive circuit and a plurality of conductive bus connection rows, and the FFC conductive circuit is connected to each conductive bus connection row through a nickel sheet.

[0042] The fire-retardant adhesive comprises 40 parts (in terms of solid content) of thermosetting acrylic resin (DC260B, solvent butyl acetate, solid content 60%), 20 parts (in terms of solid content) of bisphenol A type epoxy resin (E-44), 10 parts of curing agent 4,4'-diamino diphenyl sulfone, and 60 parts of fire-retardant agent diethyl aluminum phosphinate. The preparation method of the fire-retardant adhesive is as follows: the raw materials are weighed according to the weight parts, and the thermosetting acrylic resin, the bisphenol A type epoxy resin, the curing agent 4,4'-diamino diphenyl sulfone and the fire-retardant agent diethyl aluminum phosphinate are stirred and mixed uniformly to obtain the fire-retardant adhesive.

[0043] Example 3

[0044] A battery module collection integrated assembly with fire-retardant property comprises a PET base film coated with a fire-retardant adhesive layer and a collection circuit assembly heat-pressed and packaged on one side of the fire-retardant adhesive layer of the PET base film. The battery module collection integrated assembly with fire-retardant property is prepared by the following method:

[0045] The fire-retardant adhesive is coated on a PET base film with a thickness of 0.4 mm, the thickness of the fire-retardant adhesive coating is 0.7 mm, then the battery module collection integrated assembly with fire-retardant property is obtained by fixing the collection circuit assembly and then heat-pressing and packaging and curing. The collection circuit assembly comprises an FDC conductive circuit and a plurality of conductive bus connection rows, and the FDC is directly connected to each conductive bus connection row.

[0046] The fire-retardant adhesive comprises 40 parts (in terms of solid content) of acrylic resin, 20 parts (in terms of solid content) of bisphenol A type epoxy resin (E-44), 10 parts of curing agent 4,4'-diamino diphenyl sulfone, and 60 parts of fire-retardant agent diethyl aluminum phosphinate. The preparation method of the fire-retardant adhesive is as follows:

[0047] (1) Methyl methacrylate and butyl acrylate are mixed in a mass ratio of 1:2, then diluted with ethyl acetate solvent to a solid content of 40%, and then subjected to a copolymerization reaction for 4 h at 75℃ after nitrogen deoxygenation and addition of initiator azobisisobutyronitrile to obtain an acrylic resin solution.

[0048] (2) The acrylic resin solution (40 parts in solid content) obtained in step (1) is mixed with bisphenol A type epoxy resin (E-44, 20 parts in solid content) and heated to 50°C for 1 h, then cooled to room temperature, and 60 parts of flame retardant aluminum diethyl phosphinate and 10 parts of curing agent 4,4'-diamino diphenyl sulfone are added and uniformly mixed to obtain a flame-retardant adhesive.

[0049] Example 4

[0050] A battery module acquisition integrated assembly with flame-retardant properties includes a PET base film coated with a flame-retardant adhesive layer and a collection circuit assembly heat-sealed on one side of the flame-retardant adhesive layer of the PET base film. The battery module acquisition integrated assembly with flame-retardant properties is prepared by the following method:

[0051] The flame-retardant adhesive is coated on a PET base film with a thickness of 0.5 mm, the thickness of the flame-retardant adhesive coating is 0.8 mm, and then the collection circuit assembly is pasted and fixed, and the whole is heat-sealed and cured to obtain a battery module acquisition integrated assembly with flame-retardant properties. The collection circuit assembly includes an FDC conductive circuit and a plurality of conductive bus connection rows, and the FDC is individually connected to each conductive bus connection row through a nickel sheet.

[0052] The flame-retardant adhesive includes modified acrylic resin 40 parts (in solid content), bisphenol A type epoxy resin (E-44) 20 parts (in solid content), curing agent 4,4'-diamino diphenyl sulfone 10 parts, and flame retardant aluminum diethyl phosphinate 60 parts. The preparation method of the flame-retardant adhesive is as follows:

[0053] (1) Terephthalic acid, isocyanate acrylate ethyl ester, and catalyst dibutyltin dilaurate are added to ethyl acetate solvent and heated and stirred to react. The molar ratio of terephthalic acid to isocyanate acrylate ethyl ester is 1:2, the amount of catalyst added is 0.4% of the mass of polymerized monomers, the temperature of heating and stirring is 85°C, and the reaction time is 3 h to obtain a crosslinking monomer solution.

[0054] (2) The crosslinking monomer solution (in crosslinking monomer content) obtained in step (1) is mixed with methyl methacrylate and butyl acrylate in a mass ratio of 0.15:1:2, then diluted with ethyl acetate solvent to a solid content of 40%, deoxygenated with nitrogen, and then added with initiator azobisisobutyronitrile, heated to 75°C, and copolymerized for 4 h to obtain a modified acrylic resin solution.

[0055] (3) The modified acrylic resin solution (40 parts in solid content) obtained in step (2) is mixed with bisphenol A type epoxy resin (E-44, 20 parts in solid content), heated to 50°C for 1 h, then cooled to room temperature, and 60 parts of flame retardant aluminum diethyl phosphinate and 10 parts of curing agent 4,4'-diamino diphenyl sulfone are added and uniformly mixed to obtain a flame-retardant adhesive.

[0056] Comparative Example 1

[0057] This comparative example compared with Example 4, the preparation process of the flame-retardant adhesive uses conventional ethylene glycol dimethacrylate (EGDMA) crosslinking agent, and the preparation method of the flame-retardant adhesive is as follows:

[0058] (1) ethylene glycol dimethacrylate (EGDMA) crosslinking monomer was mixed with methacrylic acid and butyl acrylate at a mass ratio of 0.15:1:2, then diluted with ethyl acetate to a solid content of 40%, and then added with initiator azobisisobutyronitrile after nitrogen deoxidization, heated to 75°C for copolymerization reaction for 4h to obtain a modified acrylic resin solution.

[0059] (2) the modified acrylic resin solution obtained in step (1) (40 parts in terms of solid content) was mixed with bisphenol A type epoxy resin (E-44, 20 parts in terms of solid content), then heated to 50°C for reaction for 1h, then cooled to room temperature, and then added with 60 parts of flame retardant aluminum diethyl phosphinate and 10 parts of curing agent 4,4'-diamino diphenyl sulfone and mixed uniformly to obtain a flame-retardant adhesive.

[0060] The peel strength (180° peel strength test after the flame-retardant adhesive was coated on a PET base film and heat-pressed and cured), mechanical properties (tensile strength test by using a universal mechanical testing machine after the flame-retardant adhesive was dried into a film) and heat resistance (whether delamination and cracking occurred after the flame-retardant adhesive was used for the composite bonding of two pieces of glass fiber cloth, heat-pressed and cured, and then placed in a 300°C oven for baking for 5min) of the flame-retardant adhesive obtained in the above examples and comparative examples were tested, and the results are shown in Table 1 below.

[0061] Table 1

[0062] As can be seen from the results in Table 1, the flame-retardant glue adopted in the present application has good heat resistance, and can realize good bonding and fixing under high temperature conditions. As can be seen from the comparison results of Example 1 and Example 2, the bonding strength of the flame-retardant glue resin to the PET base film is significantly improved by using epoxy resin alone compared with the mixture of acrylic resin and epoxy resin, but the mechanical strength of the glue film is reduced. As can be seen from the comparison results of Example 2 and Example 3, the bonding force of the glue film layer to the PET base film and the mechanical strength of the glue film can be improved by grafting reaction of the epoxy resin and the acrylic acid segment in the acrylic resin. As can be seen from the comparison results of Example 3 and Example 4, the bonding force of the glue film layer to the PET base film and the mechanical strength of the glue film can be significantly improved by further introducing the cross-linking monomer obtained by the reaction of terephthalic acid and isocyanate acrylate ethyl ester, so that the hot-press packaging effect of the acquisition circuit assembly can be significantly improved, the high-temperature resistance and flame-retardant effect of the acquisition circuit assembly can be improved, and the safety of the battery module can be improved. As can be seen from the comparison results of Example 4 and Comparative Example 1, the bonding force of the flame-retardant glue layer to the PET base film is significantly improved by using the modified acrylic resin prepared by the cross-linking monomer of the present application compared with the conventional cross-linking monomer.

[0063] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and all shall be included in the protection scope of the present application.

Claims

1. A battery module collection integrated assembly with flame retardant properties, characterized in that, The PET base film is coated with a fire-retardant glue layer, and a collection circuit assembly is hot-pressed on one side of the fire-retardant glue layer of the PET base film; the fire-retardant glue layer comprises the following components by weight: 20-80 parts of a heat-curing resin, 5-20 parts of a curing agent, and 20-80 parts of a fire-retardant agent.

2. The battery module collection integrated assembly with the fire resistance characteristic according to claim 1, wherein, The thickness of the PET base film is 0.03-0.5 mm, and the thickness of the fire-retardant glue layer is 0.1-1 mm.

3. The battery module collection integrated assembly with the fire resistance characteristic according to claim 1, wherein, The collection circuit assembly comprises a conductive circuit and a plurality of conductive bus connection rows connected to the conductive circuit; the conductive circuit is FPC, the FPC is connected to each conductive bus connection row through a nickel sheet relay; or the conductive circuit is FFC, the FFC is connected to each conductive bus connection row through a nickel sheet relay; or the conductive circuit is FDC, the FDC is connected to each conductive bus connection row through a nickel sheet relay or the FDC is directly connected to each conductive bus connection row; or the conductive circuit is FCC, that is, the FFC circuit is connected to each conductive bus connection row through an FPC plate relay.

4. The battery module collection integrated assembly with the fire resistance characteristic according to claim 1, wherein, The heat-curing resin is one or more of nitrile rubber, epoxy resin, polyester resin, acrylic resin, and polyurethane resin; the curing agent is one or more of 4,4'-diamino diphenyl sulfone, dicyandiamide, acid anhydride, imidazole, HDI, TDI, and melamine; and the fire-retardant agent is one or more of aluminum diethyl phosphinate, hexaphenoxycyclotriphosphazene, and ammonium polyphosphate.

5. The battery module collection integrated assembly with the fire resistance characteristic according to claim 1, wherein, A mica sheet, mica paper, flexible ceramic, fireproof paper, aerogel, or ceramic sheet fire-retardant sheet layer is additionally arranged between the PET base film and the collection circuit assembly; a fire-retardant glue layer is coated between the fire-retardant sheet layer and the collection circuit assembly and between the fire-retardant sheet layer and the PET base film.

6. The battery module collection integrated assembly with the fire resistance characteristic according to claim 1, wherein, The collection circuit assembly is notched or not notched at the explosion-proof valve part of the battery cell; when notched, the collection circuit assembly is provided with or not provided with a fire-retardant glue layer on the side facing the battery cell; when not notched, the collection circuit assembly is provided with a fire-retardant glue layer on the side facing the battery cell.

7. A method for preparing a battery module data acquisition and integration component with flame-retardant properties, characterized in that, The preparation steps include: (1) adding terephthalic acid, isocyanate acrylate ethyl ester, and an organic tin catalyst into an ethyl acetate solvent to heat and stir to react, to obtain a crosslinking monomer solution; (2) mixing the crosslinking monomer solution obtained in step (1) with acrylic acid monomer and acrylic ester monomer, diluting in an ethyl acetate solvent, removing oxygen with nitrogen, adding an initiator to heat to perform copolymerization, to obtain a modified acrylic resin solution; (3) mixing the modified acrylic resin solution obtained in step (2) with an epoxy resin to heat to react, cooling to room temperature, adding a fire-retardant agent and a curing agent to mix uniformly, to obtain a mixed glue solution; (4) coating the mixed glue solution obtained in step (3) on a PET base film, then pasting and fixing a collection circuit assembly to perform overall hot-pressing encapsulation and curing, to obtain a battery module collection integrated assembly with fire-retardant properties.

8. The method of claim 7, wherein the battery module collection integrated assembly having a fire retardant property is prepared by the steps of: In step (1), the molar ratio of terephthalic acid to isocyanate acrylate ethyl ester is 1:2; the organic tin catalyst is dibutyltin dilaurate; and the temperature of the heating and stirring reaction is 60-90°C. ​ 9. The method of claim 7, wherein the battery module collection integrated assembly having a fire retardant property is prepared by the steps of: The acrylic acid monomer in step (2) is a mixture of one or both of acrylic acid and methacrylic acid; the acrylic ester monomer is at least one of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, butyl acrylate, butyl methacrylate, isooctyl acrylate, and isooctyl methacrylate. ​ 10. The method of claim 7, wherein the battery module collection integrated assembly having a fire retardant property is prepared by the steps of: The mass ratio of the crosslinking monomer to the acrylic acid monomer and the acrylic ester monomer in the crosslinking monomer solution in step (2) is 0.05-0.3:1-2:1-2. ​ 11. The method of claim 7, wherein the battery module collection integrated assembly having a fire retardant property is prepared by the steps of: The amount of the ethyl acetate solvent added in step (2) is such that the solid content of the reaction system is 30%-50%; the initiator is azobisisobutyronitrile or azobisisoheptyl nitrile; and the temperature for the copolymerization reaction is 60-80°C. ​ 12. The method of claim 7, wherein the battery module collection integrated assembly having a fire retardant property is prepared by the steps of: The epoxy resin in step (3) is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin; and the mass ratio of the modified acrylic resin to the epoxy resin in the modified acrylic resin solution is 2-4:1-2. ​ 13. The method of claim 7, wherein the battery module collection integrated assembly having a flame retardant property is prepared by the steps of: The temperature for the heating reaction in step (3) is 40-60°C, and the heating reaction time is 0.5-3h. ​ 14. The method of claim 7, wherein the battery module collection integrated assembly having a fire retardant property is prepared by the steps of: The mixed glue solution in step (4) is coated on the PET base film using a roll-to-roll process. ​

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