Flame-retardant FDC acquisition circuit, preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of battery acquisition circuit assemblies. Disclosed are a flame-retardant FDC acquisition circuit, a preparation method therefor, and a use thereof. The flame-retardant FDC acquisition circuit comprises an intermediate copper circuit layer and upper and lower encapsulant film layers; and a thermosetting flame-retardant adhesive layer is provided between the intermediate copper circuit layer and at least one of the upper and lower encapsulant film layers. The thermosetting flame-retardant adhesive layer is prepared by means of the following method: reacting terephthalic acid or p-phenylenediamine with 2 isocyanatoethyl acrylate to obtain a crosslinking monomer; then performing a copolymerization reaction on the crosslinking monomer, an acrylic monomer and an acrylate monomer to obtain a modified acrylic resin; then mixing the modified acrylic resin with an epoxy resin, then heating and reacting the mixture, and adding a flame retardant and a curing agent for uniform mixing to obtain a flame-retardant adhesive solution; and applying the obtained flame-retardant adhesive solution to an encapsulant film layer and curing same to obtain the thermosetting flame-retardant adhesive layer. By using a specific thermosetting flame-retardant adhesive layer, the present invention can achieve the flame-retardant and high-temperature-resistant effects of FDC acquisition circuits, thereby reducing the risk of fire and combustion of battery packs.

Description

A flame-retardant FDC acquisition circuit, its fabrication method and application Technical Field

[0001] This invention belongs to the technical field of battery acquisition circuit components, specifically relating to a flame-retardant FDC acquisition circuit, its preparation method, and its application. Background Technology

[0002] With the rapid development of industries such as new energy vehicles and energy storage, the CCS integrated busbar market is also expanding rapidly. Simultaneously, advancements in battery integration technology and the increasing demand for automation in large-scale production are leading to the gradual replacement of traditional wire harness CCS solutions with integrated and lightweight FPC (Flexible Printed Circuit) solutions. Furthermore, compared to FPC solutions, more cost-effective FFC (Flexible Flat Cable) and FDC (Flexible Die Cutting Circuit) solutions are also continuously being developed. Traditional wire harness + injection molded bracket solutions offer lower costs and better stability, but require manual assembly, have low automation levels, and are not conducive to mass production. Compared to wire harness solutions, CCS integrated busbars using FPC / FFC + vacuum forming plates or hot pressing methods offer a thinner, more streamlined structure and higher integration, which is beneficial for improving battery pack space utilization and assembly efficiency, aligning with the trends of automotive lightweighting, component system integration, and large-module modularization.

[0003] However, due to the complex operating conditions of battery packs, there is currently no mature technology in the industrial field to completely prevent thermal runaway of battery cells. When thermal runaway occurs in a battery cell, the explosion-proof valve will activate to release the high-temperature, high-pressure gas from the cell. This high-temperature, high-pressure gas often reaches temperatures above 500°C. Although most CCS products on the market are made of flame-retardant materials, the organic adhesive film covering the surface of the acquisition circuit (such as FPC) has a temperature resistance rating of only 150°C (PET) or 250°C (PI). When exposed to temperatures of 500°C, it will soften, fluidize, and shrink and deform. This will lead to a deterioration in the fixation of the copper circuitry. Once a short circuit occurs, sparking will occur, causing an uncontrollable and violent combustion of the entire battery pack, resulting in significant property damage and personal injury.

[0004] In our earlier patent CN116505204A, flame-retardant sheets such as mica sheets, flexible ceramic sheets, Mylar sheets, or fire-retardant paper were adhered to the adhesive film layer to achieve a flame-retardant effect and improve circuit stability and safety. However, this method of adhering flame-retardant sheets increases the battery pack assembly process, and the adhesion stability of the flame-retardant sheets is poor. Furthermore, the tightness of the sheets with the data acquisition circuit components is also poor, making them prone to delamination in the event of thermal runaway of the battery cell. Therefore, the reliability of the flame-retardant effect needs further improvement.

[0005] Therefore, developing a signal acquisition circuit suitable for new energy batteries, with a simple and low-cost manufacturing process, and stable flame-retardant and high-temperature resistant properties, has good application prospects. Summary of the Invention

[0006] In view of the shortcomings and deficiencies of the existing technology, the primary objective of this invention is to provide a flame-retardant FDC acquisition circuit.

[0007] Another object of the present invention is to provide a method for preparing the above-mentioned flame-retardant FDC acquisition circuit.

[0008] Another object of the present invention is to provide the application of the above-mentioned flame-retardant FDC acquisition circuit in a battery module acquisition integration component.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] A flame-retardant FDC acquisition circuit includes an intermediate copper circuit layer and upper and lower encapsulation film layers, wherein at least one layer between the intermediate copper circuit layer and the upper and lower encapsulation film layers is provided with a thermosetting flame-retardant adhesive layer.

[0011] The thermosetting flame-retardant adhesive layer is prepared by the following method:

[0012] (1) Terephthalic acid or p-phenylenediamine and ethyl isocyanate acrylate are added to ethyl acetate solvent and heated and stirred to react, so as to obtain a crosslinking monomer solution;

[0013] (2) The crosslinking monomer solution obtained in step (1) is mixed with acrylic monomer and acrylate monomer, diluted with ethyl acetate solvent, deoxygenated with nitrogen, and then an initiator is added and heated to carry out a copolymerization reaction to obtain a modified acrylic resin solution.

[0014] (3) After mixing the modified acrylic resin solution obtained in step (2) with epoxy resin, heat and react. After cooling to room temperature, add flame retardant and curing agent and mix well to obtain flame retardant adhesive.

[0015] (4) The flame retardant adhesive obtained in step (3) is applied to the encapsulation film layer and cured to obtain a thermosetting flame retardant adhesive layer.

[0016] Further, the molar ratio of terephthalic acid or p-phenylenediamine to ethyl isocyanate acrylate in step (1) is 1:2.

[0017] Furthermore, in step (1), when the reactant is terephthalic acid, dibutyltin dilaurate is added as a catalyst, and the temperature of the heating and stirring reaction is 60-90°C; when the reactant is p-phenylenediamine, the temperature of the heating and stirring reaction is 30-60°C.

[0018] Further, the acrylic monomer in step (2) is one or a mixture of acrylic acid and methacrylic acid; the acrylate 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.

[0019] Further, in step (2), the mass ratio of the crosslinking monomer to the acrylic monomer and the acrylate monomer in the crosslinking monomer solution is 0.05-0.3:1-2:1-2.

[0020] Further, in step (2), the amount of ethyl acetate solvent added for dilution is such that the solid content of the reaction system is 30% to 50%; the initiator is azobisisobutyronitrile or azobisisoheptanenitrile; and the temperature for the copolymerization reaction is 60 to 80°C.

[0021] Further, the epoxy resin in step (3) is a bisphenol A type epoxy resin or a bisphenol F type epoxy resin; the mass ratio of the modified acrylic resin to the epoxy resin in the modified acrylic resin solution is 2-4:1-2.

[0022] Furthermore, the heating reaction temperature in step (3) is 40–60°C, and the heating reaction time is 0.5–3 h. The heating reaction causes some of the epoxy groups in the epoxy resin to graft onto the acrylic segments in the modified acrylic resin, thereby improving the compatibility stability of the mixed adhesive and enhancing the bonding and curing effect of the flame-retardant adhesive.

[0023] Further, the flame retardant mentioned in step (3) is one or more of aluminum diethylphosphonate, hexaphenoxycyclotriphosphazene, and ammonium polyphosphate; the amount of flame retardant added is 0.25 to 4 times the total mass of modified acrylic resin and epoxy resin.

[0024] Further, the curing agent mentioned in step (3) is one or more of 4,4'-diaminodiphenyl sulfone, dicyandiamide, acid anhydride, imidazole, HDI, TDI, and melamine; the amount of curing agent added is 0.05 to 1 times the total mass of the modified acrylic resin and epoxy resin.

[0025] Furthermore, the mixed adhesive solution described in step (4) is applied to the encapsulation film layer using a roll-to-roll process.

[0026] Furthermore, the upper and lower encapsulating film layers are PET (polyester) or PI (polyimide) films.

[0027] Furthermore, the thickness of the upper and lower encapsulating film layers is 0.03–0.5 mm, and the thickness of the thermosetting flame-retardant adhesive layer is 0.05–1 mm.

[0028] The fabrication method of the above-mentioned flame-retardant FDC acquisition circuit includes the following fabrication steps:

[0029] After copper foil is die-cut into shape, it is hot-pressed and cured with an encapsulating film layer coated with flame-retardant adhesive to obtain a flame-retardant FDC acquisition circuit.

[0030] The above-mentioned flame-retardant FDC acquisition circuit is used in the battery module acquisition integration component.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] (1) By setting a thermosetting flame-retardant adhesive layer between the copper circuit layer and the encapsulation film layer in the FDC acquisition circuit, the present invention can achieve tight bonding and fixation between the copper circuit layer and the encapsulation film layer, while achieving flame-retardant and high-temperature resistance effects, effectively reducing the short circuit and sparking of the copper circuit when the cell is thermally runaway, and reducing the risk of fire and combustion of the battery pack.

[0033] (2) The invention further adopts a modified thermosetting resin system that reacts modified acrylic resin with epoxy resin, which has good thermosetting effect and bonding effect; by using specific crosslinking monomers to copolymerize and crosslink the acrylic resin, the cohesive strength of the resin can be improved on the one hand, and the bonding force with the encapsulation film can be improved on the other hand, thereby improving the bonding and fixing strength between the flame retardant adhesive layer and the encapsulation film and the copper circuit, realizing the bonding and hot-pressing encapsulation and fixing of the copper circuit under the condition of high flame retardant addition, and ultimately improving the structural stability and flame retardant effect of the FDC acquisition circuit.

[0034] (3) The flame-retardant FDC acquisition circuit with thermosetting flame-retardant adhesive layer of the present invention can be manufactured by roll-to-roll process. Compared with conventional high temperature resistant insulating flame-retardant sheet composite scheme, it has the advantages of high reliability, high production efficiency and low cost. Attached Figure Description

[0035] Figure 1 is a schematic diagram of the overall structure of a flame-retardant FDC acquisition circuit in an embodiment;

[0036] Figure 2 is a schematic diagram of the stacked structure of a flame-retardant FDC acquisition circuit in an embodiment. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0038] Example 1

[0039] A flame-retardant FDC acquisition circuit, the overall structure schematic diagram and the stacked structure schematic diagram of which are shown in Figure 1 and Figure 2 respectively. It includes an intermediate copper circuit layer and upper and lower encapsulation film layers, and a thermosetting flame-retardant adhesive layer is disposed between the intermediate copper circuit layer and the upper and lower encapsulation film layers.

[0040] The flame-retardant FDC acquisition circuit is prepared by the following method:

[0041] (1) Terephthalic acid, ethyl isocyanate and dibutyltin dilaurate catalyst were added to ethyl acetate solvent and heated and stirred. The molar ratio of terephthalic acid to ethyl isocyanate was 1:2, the amount of catalyst added was 0.4% of the mass of the monomer, the heating and stirring temperature was 85℃, and the reaction time was 3h to obtain a crosslinking monomer solution.

[0042] (2) The crosslinking monomer solution obtained in step (1) (based on the crosslinking monomer content) is mixed with methacrylic acid and butyl acrylate in a mass ratio of 0.15:1:2, and then diluted with ethyl acetate solvent to a solid content of 40%. After deoxygenation with nitrogen, the initiator azobisisobutyronitrile is added, and the mixture is heated to 75°C for copolymerization reaction for 4 hours to obtain a modified acrylic resin solution.

[0043] (3) The modified acrylic resin solution obtained in step (2) (40 parts by solid content) is mixed with bisphenol A type epoxy resin (E-44, 20 parts by solid content) and heated to 50°C for 1 hour. Then it is cooled to room temperature, and 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone are added and mixed to obtain flame retardant adhesive.

[0044] (4) The flame retardant adhesive obtained in step (3) is coated onto a 0.3 mm thick PET encapsulation film through a roll-to-roll process. The thickness of the flame retardant adhesive coating is 0.5 mm, thus obtaining a PET encapsulation film coated with a flame retardant adhesive layer.

[0045] (5) After the copper foil is die-cut into shape, it is hot-pressed and cured with a PET encapsulation film coated with flame-retardant adhesive to obtain a flame-retardant FDC acquisition circuit.

[0046] Example 2

[0047] A flame-retardant FDC acquisition circuit includes an intermediate copper circuit layer and upper and lower encapsulation film layers, wherein a thermosetting flame-retardant adhesive layer is disposed between the intermediate copper circuit layer and the upper encapsulation film layer.

[0048] The flame-retardant FDC acquisition circuit is prepared by the following method:

[0049] (1) Terephthalic acid, ethyl isocyanate and dibutyltin dilaurate catalyst were added to ethyl acetate solvent and heated and stirred. The molar ratio of terephthalic acid to ethyl isocyanate was 1:2, the amount of catalyst added was 0.4% of the mass of the monomer, the heating and stirring temperature was 75℃, and the reaction time was 4h to obtain a crosslinking monomer solution.

[0050] (2) The crosslinking monomer solution obtained in step (1) (based on the crosslinking monomer content) is mixed with methacrylic acid and butyl acrylate in a mass ratio of 0.05:1:1, and then diluted with ethyl acetate solvent to a solid content of 40%. After deoxygenation with nitrogen, the initiator azobisisobutyronitrile is added, and the mixture is heated to 75°C for copolymerization reaction for 4 hours to obtain a modified acrylic resin solution.

[0051] (3) The modified acrylic resin solution obtained in step (2) (30 parts by solid content) is mixed with bisphenol A type epoxy resin (E-44, 30 parts by solid content) and heated to 40°C for 3 hours. Then it is cooled to room temperature, and 100 parts of flame retardant hexaphenoxycyclotriphosphazene and 20 parts of curing agent 4,4'-diaminodiphenyl sulfone are added and mixed to obtain flame retardant adhesive.

[0052] (4) The flame retardant adhesive obtained in step (3) is coated onto a 0.4 mm thick PET encapsulation film through a roll-to-roll process. The thickness of the flame retardant adhesive coating is 0.6 mm, thus obtaining a PET encapsulation film coated with a flame retardant adhesive layer.

[0053] (5) After the copper foil is die-cut into shape, a PET encapsulation film coated with flame-retardant adhesive layer is used as the upper encapsulation film layer and an ordinary PET film is used as the lower encapsulation film layer for hot pressing and curing to obtain a flame-retardant FDC acquisition circuit.

[0054] Example 3

[0055] A flame-retardant FDC acquisition circuit includes an intermediate copper circuit layer and upper and lower encapsulation film layers, wherein a thermosetting flame-retardant adhesive layer is disposed between the intermediate copper circuit layer and the lower encapsulation film layer.

[0056] The flame-retardant FDC acquisition circuit is prepared by the following method:

[0057] (1) Terephthalic acid, ethyl isocyanate and dibutyltin dilaurate catalyst were added to ethyl acetate solvent and heated and stirred. The molar ratio of terephthalic acid to ethyl isocyanate was 1:2, the amount of catalyst added was 0.4% of the mass of the monomer, the heating and stirring temperature was 70℃, and the reaction time was 5h to obtain a crosslinking monomer solution.

[0058] (2) The crosslinking monomer solution obtained in step (1) (based on the crosslinking monomer content) is mixed with methacrylic acid and butyl acrylate in a mass ratio of 0.3:2:1, and then diluted with ethyl acetate solvent to a solid content of 40%. After deoxygenation with nitrogen, the initiator azobisisobutyronitrile is added, and the mixture is heated to 75°C for copolymerization reaction for 4 hours to obtain a modified acrylic resin solution.

[0059] (3) The modified acrylic resin solution obtained in step (2) (60 parts by solid content) is mixed with bisphenol F type epoxy resin (20 parts by solid content) and heated to 60°C for 0.5h. Then, it is cooled to room temperature, and 50 parts of flame retardant ammonium polyphosphate and 5 parts of curing agent dicyandiamide are added and mixed to obtain flame retardant adhesive.

[0060] (4) The flame retardant adhesive obtained in step (3) is coated onto a 0.5 mm thick PET encapsulation film through a roll-to-roll process. The thickness of the flame retardant adhesive coating is 0.8 mm, thus obtaining a PET encapsulation film coated with a flame retardant adhesive layer.

[0061] (5) After the copper foil is die-cut into shape, a PET encapsulation film coated with flame-retardant adhesive layer is used as the lower encapsulation film layer and an ordinary PET film is used as the upper encapsulation film layer for hot pressing and curing to obtain a flame-retardant FDC acquisition circuit.

[0062] Example 4

[0063] A flame-retardant FDC acquisition circuit, the overall structure schematic diagram and the stacked structure schematic diagram of which are shown in Figure 1 and Figure 2 respectively. It includes an intermediate copper circuit layer and upper and lower encapsulation film layers, and a thermosetting flame-retardant adhesive layer is disposed between the intermediate copper circuit layer and the upper and lower encapsulation film layers.

[0064] The flame-retardant FDC acquisition circuit is prepared by the following method:

[0065] (1) p-phenylenediamine and ethyl isocyanate acrylate were added to ethyl acetate solvent and heated and stirred to react. The molar ratio of p-phenylenediamine to ethyl isocyanate acrylate was 1:2, the heating and stirring temperature was 40℃, and the reaction time was 0.5h to obtain a crosslinking monomer solution.

[0066] (2) The crosslinking monomer solution obtained in step (1) (based on the crosslinking monomer content) is mixed with methacrylic acid and butyl acrylate in a mass ratio of 0.15:1:2, and then diluted with ethyl acetate solvent to a solid content of 40%. After deoxygenation with nitrogen, the initiator azobisisobutyronitrile is added, and the mixture is heated to 75°C for copolymerization reaction for 4 hours to obtain a modified acrylic resin solution.

[0067] (3) The modified acrylic resin solution obtained in step (2) (40 parts by solid content) is mixed with bisphenol A type epoxy resin (E-44, 20 parts by solid content) and heated to 50°C for 1 hour. Then it is cooled to room temperature, and 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone are added and mixed to obtain flame retardant adhesive.

[0068] (4) The flame retardant adhesive obtained in step (3) is coated onto a 0.3 mm thick PI encapsulation film through a roll-to-roll process. The thickness of the flame retardant adhesive coating is 0.5 mm, thus obtaining a PI encapsulation film coated with a flame retardant adhesive layer.

[0069] (5) After the copper foil is die-cut into shape, it is hot-pressed and cured with PI encapsulation film coated with flame-retardant adhesive to obtain flame-retardant FDC acquisition circuit.

[0070] Comparative Example 1

[0071] The preparation method of the flame-retardant adhesive in this comparative example, compared with Example 1, uses a single epoxy resin as the bonding resin, which is prepared by the following method:

[0072] Bisphenol A type epoxy resin (E-44, 60 parts by solid content) was mixed with 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone at room temperature to obtain flame retardant adhesive.

[0073] Comparative Example 2

[0074] The preparation method of the flame retardant adhesive in this comparative example, compared with Example 1, involves a modified acrylic resin solution that is not pre-treated with epoxy resin through a heating modification reaction. It is prepared by the following method:

[0075] The modified acrylic resin solution (40 parts by solid content) obtained in step (2) of Example 1 was mixed with bisphenol A type epoxy resin (E-44, 20 parts by solid content) at room temperature with 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone to obtain flame retardant adhesive.

[0076] Comparative Example 3

[0077] The preparation method of the flame retardant adhesive in this comparative example, compared with Example 1, involves the preparation of the modified acrylic resin without the addition of crosslinking monomers, and it is prepared by the following method:

[0078] (1) Mix methacrylic acid and butyl acrylate in a mass ratio of 1:2, dilute with ethyl acetate solvent to a solid content of 40%, remove oxygen with nitrogen, add initiator azobisisobutyronitrile, heat to 75°C for copolymerization reaction for 4 hours to obtain acrylic resin solution.

[0079] (2) The acrylic resin solution obtained in step (1) (40 parts by solid content) is mixed with bisphenol A type epoxy resin (E-44, 20 parts by solid content) and heated to 50°C for 1 hour. Then, it is cooled to room temperature, and 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone are added and mixed to obtain flame retardant adhesive.

[0080] Comparative Example 4

[0081] The preparation method of the flame retardant adhesive in this comparative example, compared with Example 1, uses a conventional ethylene glycol dimethacrylate (EGDMA) crosslinking agent to prepare the modified acrylic resin, which is obtained by the following method:

[0082] (1) The crosslinking monomer ethylene glycol dimethacrylate (EGDMA) was mixed with methacrylic acid and butyl acrylate in a mass ratio of 0.15:1:2 and diluted with ethyl acetate solvent to a solid content of 40%. After deoxygenation with nitrogen, the initiator azobisisobutyronitrile was added and the mixture was heated to 75°C for copolymerization reaction for 4 hours to obtain a modified acrylic resin solution.

[0083] (2) The modified acrylic resin solution obtained in step (1) (40 parts by solid content) is mixed with bisphenol A type epoxy resin (E-44, 20 parts by solid content) and heated to 50°C for 1 hour. Then it is cooled to room temperature, and 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone are added and mixed to obtain flame retardant adhesive.

[0084] Comparative Example 5

[0085] This comparative example describes a method for preparing a flame-retardant adhesive. Compared to Example 4, it uses an aliphatic diamine, 1,6-hexanediamine, instead of p-phenylenediamine to prepare the crosslinking monomer. The specific preparation steps are as follows:

[0086] (1) 1,6-hexanediamine and ethyl isocyanate acrylate were added to ethyl acetate solvent and heated and stirred to react. The molar ratio of 1,6-hexanediamine to ethyl isocyanate acrylate was 1:2. The heating and stirring temperature was 40℃ and the reaction time was 0.5h to obtain a crosslinking monomer solution.

[0087] (2) The crosslinking monomer solution obtained in step (1) (based on the crosslinking monomer content) is mixed with methacrylic acid and butyl acrylate in a mass ratio of 0.15:1:2, and then diluted with ethyl acetate solvent to a solid content of 40%. After deoxygenation with nitrogen, the initiator azobisisobutyronitrile is added, and the mixture is heated to 75°C for copolymerization reaction for 4 hours to obtain a modified acrylic resin solution.

[0088] (3) The modified acrylic resin solution obtained in step (2) (40 parts by solid content) is mixed with bisphenol A type epoxy resin (E-44, 20 parts by solid content) and heated to 50°C for 1 hour. Then it is cooled to room temperature, and 60 parts of flame retardant aluminum diethylphosphinate and 10 parts of curing agent 4,4'-diaminodiphenyl sulfone are added and mixed to obtain flame retardant adhesive.

[0089] The peel strength (180° peel force test was performed after the flame retardant adhesive was coated onto a PET base film and cured by hot pressing in Examples 1 and 4 and Comparative Examples 1 to 5), mechanical properties (tensile strength was tested by a universal testing machine after the flame retardant adhesive was dried into a film), and heat resistance (the flame retardant adhesive was used for the composite bonding of two pieces of fiberglass cloth, and after hot pressing and curing, it was placed in a 300° oven for 5 minutes to observe whether it delaminated or cracked) of the flame retardant adhesive obtained in Examples 1 and 4 and Comparative Examples 1 to 5 were tested. The results are shown in Table 1 below.

[0090] Table 1

[0091] The comparison results between Example 1 and Comparative Example 1 show that the flame-retardant adhesive of the present invention uses a mixture of modified acrylic resin and epoxy resin as the bonding resin, which significantly improves the bonding force and strength of the flame-retardant adhesive compared to epoxy resin alone. The comparison results between Example 1 and Comparative Example 2 show that pre-reacting the modified acrylic resin with the epoxy resin can significantly improve the bonding force and strength of the flame-retardant adhesive. The comparison results between Example 1 and Comparative Example 3 show that the preparation of the modified acrylic resin by introducing specific crosslinking monomers can significantly improve the bonding force and strength of the flame-retardant adhesive. The comparison results between Example 1 and Comparative Examples 3-4 show that while introducing conventional crosslinking monomers in the preparation of the modified acrylic resin can improve the mechanical strength of the flame-retardant adhesive, it has an adverse effect on the bonding force. The comparison results between Example 4 and Comparative Example 5 show that using p-phenylenediamine to prepare the crosslinking monomers significantly improves the bonding force and strength of the resulting flame-retardant adhesive compared to linear aliphatic diamines.

[0092] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A flame-retardant FDC acquisition circuit, characterized in that, It includes an intermediate copper circuit layer and upper and lower encapsulation film layers, wherein at least one layer between the intermediate copper circuit layer and the upper and lower encapsulation film layers is provided with a thermosetting flame retardant adhesive layer; The thermosetting flame-retardant adhesive layer is prepared by the following method: (1) Terephthalic acid or p-phenylenediamine and ethyl isocyanate acrylate are added to ethyl acetate solvent and heated and stirred to react, so as to obtain a crosslinking monomer solution; (2) The crosslinking monomer solution obtained in step (1) is mixed with acrylic monomer and acrylate monomer, diluted with ethyl acetate solvent, deoxygenated with nitrogen, and then an initiator is added and heated to carry out a copolymerization reaction to obtain a modified acrylic resin solution. (3) After mixing the modified acrylic resin solution obtained in step (2) with epoxy resin, heat and react. After cooling to room temperature, add flame retardant and curing agent and mix well to obtain flame retardant adhesive. (4) The flame retardant adhesive obtained in step (3) is applied to the encapsulation film layer and cured to obtain a thermosetting flame retardant adhesive layer.

2. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, The molar ratio of terephthalic acid or p-phenylenediamine to ethyl isocyanate acrylate in step (1) is 1:

2.

3. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, When the reactant in step (1) is terephthalic acid, dibutyltin dilaurate is added as a catalyst, and the temperature of the heating and stirring reaction is 60-90°C; when the reactant is p-phenylenediamine, the temperature of the heating and stirring reaction is 30-60°C.

4. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, The acrylic monomer mentioned in step (2) is one or a mixture of acrylic acid and methacrylic acid; the acrylate 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.

5. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, The mass ratio of the crosslinking monomer to the acrylic monomer and acrylate monomer in the crosslinking monomer solution in step (2) is 0.05-0.3:1-2:1-2.

6. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, In step (2), the amount of ethyl acetate solvent added for dilution is such that the solid content of the reaction system is 30% to 50%; the initiator is azobisisobutyronitrile or azobisisoheptanenitrile; and the temperature for the copolymerization reaction is 60 to 80°C.

7. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, The epoxy resin in step (3) is bisphenol A type epoxy resin or bisphenol F type epoxy resin; the mass ratio of the modified acrylic resin to the epoxy resin in the modified acrylic resin solution is 2-4:1-2; the heating reaction temperature is 40-60℃ and the heating reaction time is 0.5-3h.

8. The flame-retardant FDC acquisition circuit according to claim 1, characterized in that, The flame retardant mentioned in step (3) is one or more of aluminum diethylphosphonate, hexaphenoxycyclotriphosphazene, and ammonium polyphosphate; the amount of flame retardant added is 0.25 to 4 times the total mass of modified acrylic resin and epoxy resin; the curing agent is one or more of 4,4'-diaminodiphenyl sulfone, dicyandiamide, acid anhydride, imidazole, HDI, TDI, and melamine; the amount of curing agent added is 0.05 to 1 times the total mass of modified acrylic resin and epoxy resin.

9. A flame-retardant FDC acquisition circuit according to claim 1, characterized in that, In step (4), the mixed adhesive solution is applied to the encapsulation film layer using a roll-to-roll process.

10. A flame-retardant FDC acquisition circuit according to claim 1, characterized in that, The upper and lower encapsulation film layers are PET or PI films; the thickness of the upper and lower encapsulation film layers is 0.03-0.5 mm, and the thickness of the thermosetting flame retardant adhesive layer is 0.05-1 mm.

11. A method for preparing a flame-retardant FDC acquisition circuit according to any one of claims 1 to 10, characterized in that, The preparation steps include the following: After copper foil is die-cut into shape, it is hot-pressed and cured with an encapsulating film layer coated with flame-retardant adhesive to obtain a flame-retardant FDC acquisition circuit.

12. The application of the flame-retardant FDC acquisition circuit according to any one of claims 1 to 10 in a battery module acquisition integration component.

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