Energy storage battery filling buffer protection adhesive tape and preparation method thereof

Abstract

The invention discloses an energy storage battery filling buffer protection adhesive tape, and relates to the technical field of battery adhesive tapes, the energy storage battery filling buffer protection adhesive tape comprises a bearing layer, an adhesive layer and a buffer layer; the bearing layer comprises 70%-85% of polyimide resin, 10%-15% of a thermal conductive filler, 2%-5% of a silane coupling agent and the balance of a solvent, and the adhesive layer comprises 60%-70% of a matrix polymer, 20%-30% of a tackifying aid, 5%-10% of a thermal conductive filler, 0.5%-1.5% of a cross-linking agent and 2%-5% of a plasticizer. The buffer layer comprises 25%-40% of RTV vulcanized organic silicon rubber, 55%-70% of thermal conductive filler, 2%-5% of reinforcing filler, 0.5%-5% of plasticizer and 0.5%-1.5% of catalyst. The silica gel matrix, the thermal conductive filler and the auxiliary modifier are used as the outer buffer layer of the adhesive tape, so that the adhesive tape can play a role in buffering and filling during battery installation, can effectively conduct heat and assist battery heat dissipation, and is doped with the thermal conductive filler in the components of the bearing layer and the adhesive layer to further assist battery heat dissipation. And reliable guarantee is provided for safe, stable and efficient operation of the energy storage battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery tapes, and particularly to an energy storage battery filling buffer protection tape and a preparation method thereof. Background Art

[0002] In recent years, with the wide application of energy storage battery systems, the requirements for battery safety protection have been continuously improved. Traditional energy storage battery filling buffer protection tapes are mainly used to fill the gap between the battery and the outer shell, providing a certain buffer protection and bonding function. However, the existing filling buffer protection tapes have low thermal conductivity, and during the high-power operation or charge and discharge process of the battery, heat is difficult to conduct and dissipate in time, easily causing local overheating problems, which affect the battery life and safety. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides an energy storage battery filling buffer protection tape and a preparation method thereof. The specific technical solutions are as follows:

[0004] An energy storage battery filling buffer protection tape includes a carrier layer, an adhesive layer coated on the inner side of the carrier layer, and a buffer layer coated on the outer side of the carrier layer; by weight, the carrier layer is made of the following components: 70% - 85% of polyimide resin, 10% - 15% of thermal conductive filler, 2% - 5% of silane coupling agent, and the balance is solvent. The adhesive layer is made of the following components: 60% - 70% of matrix polymer, 20% - 30% of tackifying aid, 5% - 10% of thermal conductive filler, 0.5% - 1.5% of crosslinking agent, and 2% - 5% of plasticizer. The buffer layer is made of the following components: 25% - 40% of RTV vulcanized silicone rubber, 55% - 70% of thermal conductive filler, 2% - 5% of reinforcing filler, 0.5% - 5% of plasticizer, and 0.5% - 1.5% of catalyst.

[0005] Preferably:

[0006] The thermal conductive filler is hexagonal boron nitride;

[0007] The solvent is NMP or DMF;

[0008] The matrix polymer is low-viscosity PDMS;

[0009] The tackifying aid is silicone resin;

[0010] The crosslinking agent is a silane crosslinking agent;

[0011] The plasticizer is silicone oil;

[0012] The reinforcing filler is silane-coupling agent-modified nano-silica powder;

[0013] The catalyst is a tin-based catalyst or a platinum catalyst;

[0014] Preferably:

[0015] The thickness of the carrier layer is 10 - 30 μm;

[0016] The thickness of the adhesive layer is 20 - 50 μm;

[0017] The thickness of the buffer layer is 0.5 - 2 mm;

[0018] The particle size of the thermal conductivity filler in the carrier layer and the adhesive layer is 1 - 10 μm;

[0019] The particle size of the thermal conductivity filler in the buffer layer is 10 - 50 μm.

[0020] The present invention also provides a preparation method for preparing the energy storage battery filling buffer protection tape as described in any one of the above, and the preparation method includes the following steps:

[0021] Step 1: Add polyimide resin, thermal conductivity filler and silane coupling agent into a solvent, and mix in a high-shear mixer for 10 - 15 min to form a mixed solution;

[0022] Step 2: Adopt a doctor blade or casting technology to uniformly coat the mixed solution on a release substrate, pre-dry it in a ventilated and dry environment after coating, and then place it in a curing furnace and cure it at 250 - 350 °C for 30 - 60 min;

[0023] Step 3: Peel the cured film from the release substrate to obtain a flat carrier layer;

[0024] Step 4: In a high-shear mixer, dry-mix the thermal conductivity filler and the reinforcing filler for 5 - 10 min;

[0025] Step 5: Slowly add RTV vulcanized silicone rubber to the uniformly dry-mixed filler, and continue high-shear stirring for 15 - 20 min;

[0026] Step 6: Add a plasticizer and continue stirring and mixing for 3 - 5 min;

[0027] Step 7: Add a catalyst and continue stirring and mixing for 3 - 5 min;

[0028] Step 8: Transfer the mixed colloid to a vacuum degassing device to degas for 5 - 10 min;

[0029] Step 9: Adopt doctor blade coating or casting to uniformly coat the degassed colloid on one side of the carrier layer;

[0030] Step 10: Leave the carrier layer coated with colloid to stand for 10 - 15 min at 30 - 40 °C, then send it into a thermal curing furnace. Set the temperature at 80 - 120 °C, cure for 30 - 60 min, then cool it naturally to room temperature and leave it to stand for 20 - 24 h to obtain a buffer layer;

[0031] Step 11: Mix the matrix polymer, tackifying aid, thermal conductive filler, crosslinking agent and plasticizer, and stir with a high-shear stirring device for 10 - 15 min. Then place the mixture in a vacuum degassing device and degas for 5 - 10 min;

[0032] Step 12: Use a doctor blade or casting technique to coat the degassed mixture on the other side of the carrier layer. After coating, leave it to stand for 10 - 15 min at 30 - 40 °C to obtain an adhesive layer.

[0033] Preferably, in Step 11, the matrix polymer is PDMS graft-modified with reactive functional groups, the tackifying aid is a silicone resin, the thermal conductive filler is hexagonally boron nitride modified with silane, and the preparation process of the low-viscosity PDMS graft-modified with reactive functional groups includes the following steps:

[0034] Under an inert atmosphere, place low-viscosity PDMS into a reaction kettle, where the low-viscosity PDMS is PDMS containing Si-H active groups;

[0035] Add a silane coupling agent, control the reaction temperature at 80 - 120 °C, and react for 1 - 3 h. The silane coupling agent is vinyltriethoxysilane or 3-aminopropyltriethoxysilane;

[0036] After the reaction ends, cool the reaction solution to room temperature, and filter or rectify to remove unreacted silane and by-products to obtain the modified PDMS.

[0037] Preferably, Step 11 specifically includes the following sub-steps:

[0038] Step 111: In a reaction kettle, pre-mix epoxy group silane and the matrix polymer at 40 - 60 °C and react for 15 - 30 min, where the matrix polymer is low-viscosity PDMS;

[0039] Step 112: Mix the pre-mixed modified PDMS with the tackifying aid and pre-stir in a high-shear mixer for 5 - 10 minutes, where the tackifying aid is a silicone resin;

[0040] Step 113: Add the crosslinking agent, plasticizer and thermally conductive filler pretreated with silane, and continue to stir for 10 - 15 min. The crosslinking agent is a silane crosslinking agent, the plasticizer is silicone oil, and the thermally conductive filler is hexagonally boron nitride;

[0041] Step 114: Place the mixed system in a vacuum degassing device. After degassing for 5 - 10 minutes, a modified mixture is obtained.

[0042] Preferably:

[0043] The RTV curable silicone rubber described in Step 5 is an RTV curable silicone rubber graft - modified with a silane coupling agent, and the thermal conductivity filler is hexagonal boron nitride treated with a silane coupling agent;

[0044] Or the RTV curable silicone rubber is an RTV curable silicone rubber modified with a silicone copolymer;

[0045] Or the RTV curable silicone rubber is an RTV curable silicone rubber modified with a bifunctional chain extender.

[0046] Preferably, the preparation process of the RTV curable silicone rubber graft - modified with a silane coupling agent includes the following steps:

[0047] Under an inert atmosphere, mix the RTV curable rubber with a silane coupling agent, where the silane coupling agent is 3 - aminopropyltriethoxysilane;

[0048] Heat up to 80 - 100 °C and react for 1 - 2 hours under stirring conditions. After the reaction ends, cool the system to room temperature, and filter to remove unreacted substances or low - molecular - weight by - products to obtain the product.

[0049] Preferably, the RTV curable silicone rubber modified with a silicone copolymer is prepared by mixing the silicone copolymer with the RTV curable silicone rubber at 5% - 10% of the total amount of the RTV curable silicone rubber and stirring for 10 - 20 minutes.

[0050] Preferably, the RTV curable silicone rubber modified with a bifunctional chain extender is prepared by mixing the bifunctional chain extender with the RTV curable silicone rubber at 5% - 10% of the total amount of the RTV curable silicone rubber and stirring at 60 - 80 °C for 15 - 30 minutes, where the bifunctional chain extender is divinyl or dihydroxy PDMS.

[0051] The energy - storage battery filling buffer protection tape provided by the present invention is based on a silica gel matrix, a thermal conductivity filler, and an auxiliary modifier as the outer buffer layer of the tape. It can not only play a buffering and filling role during battery installation, but also effectively conduct heat to assist the battery in heat dissipation. At the same time, the thermal conductivity filler is doped in the components of the bearing layer and the adhesive layer to further assist the battery in heat dissipation, providing a reliable guarantee for the safe, stable, and efficient operation of the energy - storage battery. Detailed implementation manners

[0052] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below. The description in this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention.

[0053] This embodiment provides a filling buffer protection tape for energy storage batteries, which includes a carrier layer, an adhesive layer coated on the inner side of the carrier layer, and a buffer layer coated on the outer side of the carrier layer; by weight, the carrier layer is made of the following components: 70% - 85% of polyimide resin, 10% - 15% of thermal conductive filler, 2% - 5% of silane coupling agent, and the balance is solvent. The adhesive layer is made of the following components: 60% - 70% of matrix polymer, 20% - 30% of tackifying assistant, 5% - 10% of thermal conductive filler, 0.5% - 1.5% of crosslinking agent, and 2% - 5% of plasticizer. The buffer layer is made of the following components: 25% - 40% of RTV vulcanized silicone rubber, 55% - 70% of thermal conductive filler, 2% - 5% of reinforcing filler, 0.5% - 5% of plasticizer, and 0.5% - 1.5% of catalyst.

[0054] Among them, the carrier layer provides dimensional stability and auxiliary thermal management. The polyimide resin in the carrier layer serves as a film-forming matrix, providing good mechanical properties. The thermal conductive filler can be selected from fine-grained hexagonal boron nitride or alumina, which plays an auxiliary heat dissipation role. The silane coupling agent can improve the interfacial bonding between the filler and the polyimide matrix. The adhesive layer has good initial tack and persistent adhesiveness, ensuring tight bonding with the surface of the energy storage battery. At the same time, it can also provide a certain degree of thermal conductivity. The matrix polymer in the adhesive layer can be selected from low-viscosity PDMS or silicone rubber to form the main bonding matrix. The tackifying assistant can be selected from silicone resin to improve the bonding performance of the adhesive layer. The thermal conductive filler is the same as that in the carrier layer, which can provide a certain degree of thermal conductivity without affecting the viscosity. The plasticizer can be selected from low-molecular-weight silicone oil to improve fluidity and flexibility. The buffer layer can play a buffering and filling role during battery installation, and at the same time can effectively conduct heat, thus assisting the battery in heat dissipation. The RTV vulcanized silicone rubber in the buffer layer serves as a continuous phase, endowing the tape with flexibility and impact resistance. The selection of the thermal conductive filler is consistent with the other two layers, providing excellent thermal conductivity while maintaining electrical insulation. The particles can be selected as flakes or spheres, and the particle size is controlled within 10 - 50 μm, which is beneficial to form a thermal conduction network. The reinforcing filler is selected from ultra-fine silicon powder modified by silane coupling agent to improve the mechanical strength and aging resistance of the tape, prevent filler agglomeration. The plasticizer can be selected from low-molecular-weight silicone oil or other compatible plasticizers to adjust the flexibility of the tape and improve the processing fluidity. The catalyst can be selected from tin-based catalysts or platinum catalysts, which can promote the crosslinking and curing reaction of silicone rubber to ensure that the tape forms a stable three-dimensional network.

[0055] The energy storage battery filling buffer protection tape provided by this embodiment is based on a silicone matrix, thermal conductive filler and auxiliary modifier as the outer buffer layer of the tape. It can not only play a buffering and filling role during battery installation, but also effectively conduct heat to assist the battery in heat dissipation. At the same time, thermal conductive fillers are doped in the components of the bearing layer and the adhesive layer to further assist the battery in heat dissipation, providing a reliable guarantee for the safe, stable and efficient operation of the energy storage battery.

[0056] Furthermore:

[0057] The thermal conductive filler is hexagonal boron nitride.

[0058] The solvent is NMP or DMF.

[0059] The matrix polymer is low-viscosity PDMS.

[0060] The tackifier is silicone resin.

[0061] The crosslinking agent is a silane crosslinking agent.

[0062] The plasticizer is silicone oil.

[0063] The reinforcing filler is nano-silica powder modified by silane coupling.

[0064] The catalyst is a tin-based catalyst or a platinum catalyst.

[0065] Furthermore:

[0066] The thickness of the bearing layer is 10 - 30 μm.

[0067] The thickness of the adhesive layer is 20 - 50 μm.

[0068] The thickness of the buffer layer is 0.5 - 2 mm.

[0069] The particle size of the thermal conductive filler in the bearing layer and the adhesive layer is 1 - 10 μm.

[0070] The particle size of the thermal conductive filler in the buffer layer is 10 - 50 μm.

[0071] This embodiment also provides a preparation method for preparing the energy storage battery filling buffer protection tape as described in any one of the above. The preparation method includes the following steps:

[0072] Step 1: Add polyimide resin, thermal conductive filler and silane coupling agent into the solvent, and mix them in a high-shear mixer for 10 - 15 min to form a mixed solution.

[0073] Step 2: Use a scraper or casting technology to evenly coat the mixed solution on the release substrate. After coating, pre-dry it in a ventilated and dry environment, and then place it in a curing furnace and cure it at 250 - 350 °C for 30 - 60 min.

[0074] Step 3: Peel the cured film from the release substrate to obtain a flat carrier layer.

[0075] Step 4: In a high-shear mixer, dry-mix the thermal conductive filler and the reinforcing filler for 5 - 10 min.

[0076] Step 5: Slowly add the RTV vulcanized silicone rubber to the uniformly dry-mixed filler, and continue high-shear stirring for 15 - 20 min.

[0077] Step 6: Add the plasticizer and continue stirring and mixing for 3 - 5 min.

[0078] Step 7: Add the catalyst and continue stirring and mixing for 3 - 5 min.

[0079] Step 8: Transfer the mixed colloid to a vacuum degassing device for degassing for 5 - 10 min.

[0080] Step 9: Uniformly coat the degassed colloid on one side of the carrier layer by using a doctor blade coating or casting method.

[0081] Step 10: Leave the carrier layer coated with the colloid to stand for 10 - 15 min at 30 - 40 °C, then send it into a thermal curing furnace, set the temperature to 80 - 120 °C, cure for 30 - 60 min, then naturally cool to room temperature, and leave it to stand for 20 - 24 h to obtain the buffer layer.

[0082] Step 11: Mix the matrix polymer, tackifying aid, thermal conductive filler, crosslinking agent, and plasticizer, and use a high-shear stirring device to stir for 10 - 15 min. Then place the mixture in a vacuum degassing device for degassing for 5 - 10 min.

[0083] Step 12: Coat the degassed mixture on the other side of the carrier layer by using a doctor blade or casting technique. After coating, leave it to stand for 10 - 15 min at 30 - 40 °C to obtain the adhesive layer.

[0084] Further, in Step 11, the matrix polymer is PDMS graft-modified with reactive functional groups, the tackifying aid is a silicone resin type, the thermal conductive filler is silane-modified hexagonal boron nitride, and the preparation process of the low-viscosity PDMS graft-modified with reactive functional groups includes the following steps:

[0085] Under an inert atmosphere, place the low-viscosity PDMS into a reaction kettle, where the low-viscosity PDMS is PDMS containing Si-H active groups.

[0086] Add the silane coupling agent, control the reaction temperature at 80 - 120 °C, and react for 1 - 3 h, where the silane coupling agent is vinyltriethoxysilane or 3-aminopropyltriethoxysilane.

[0087] After the reaction is completed, the reaction solution is cooled to room temperature, and then filtered or rectified to remove unreacted silane and by-products, obtaining the modified PDMS.

[0088] The modification principle is as follows: By introducing reactive functional groups (vinyl or epoxy groups) at the ends of low-viscosity PDMS molecules, it can undergo a co-crosslinking reaction with silicone resin during the curing process to form a stronger chemical bond; meanwhile, these functional groups can also undergo an interfacial reaction with the surface of h-BN pre-modified with silane to form a chemical bridge, improving the heat conduction channels.

[0089] Furthermore, step 11 specifically includes the following sub-steps:

[0090] Step 111: In the reaction kettle, epoxy silane and the matrix polymer are pre-mixed at 40 - 60 °C for 15 - 30 min, where the matrix polymer is low-viscosity PDMS.

[0091] Step 112: The pre-mixed modified PDMS and the tackifier are mixed and pre-stirred in a high-shear mixer for 5 - 10 minutes, where the tackifier is a silicone resin type.

[0092] Step 113: The crosslinking agent, plasticizer, and thermally conductive filler pretreated with silane are added, and stirring is continued for 10 - 15 min, where the crosslinking agent is a silane crosslinking agent, the plasticizer is silicone oil, and the thermally conductive filler is hexagonal boron nitride.

[0093] Step 114: The mixed system is placed in a vacuum degassing device, and after degassing for 5 - 10 min, the modified mixture is obtained.

[0094] Among them, using the blending method, low-viscosity PDMS and part of the silicone resin are pre-mixed, and a bifunctional modified coupling agent (epoxy silane) is added to form a partial copolymer structure during the mixing process; meanwhile, the modified coupling agent can also form a bond with the surface of h-BN, thereby constructing a continuous heat conduction network and interfacial bonding layer in the adhesive layer.

[0095] Furthermore:

[0096] In step 5, the RTV vulcanized silicone rubber is the RTV vulcanized silicone rubber graft-modified with a silane coupling agent, and the thermally conductive filler is the hexagonal boron nitride treated with a silane coupling agent.

[0097] Or the RTV vulcanized silicone rubber is the RTV vulcanized silicone rubber modified with a silicone copolymer.

[0098] Or the RTV vulcanized silicone rubber is the RTV vulcanized silicone rubber modified with a bifunctional chain extender.

[0099] Further, the preparation process of the RTV vulcanized silicone rubber graft-modified with a silane coupling agent includes the following steps:

[0100] Under an inert atmosphere, mix the RTV vulcanized rubber with a silane coupling agent, where the silane coupling agent is 3-aminopropyltriethoxysilane.

[0101] Heat to 80 - 100 °C and react for 1 - 2 h under stirring conditions. After the reaction ends, cool the system to room temperature, and filter to remove unreacted substances or low-molecular-weight by-products to obtain the product.

[0102] The modification principle is as follows: The RTV vulcanized silicone rubber is graft-modified with a silane coupling agent (3-aminopropyltriethoxysilane) containing a BN-philic function and a highly flexible chain segment. After modification, reactive functional groups are introduced at the ends of the RTV molecules, which can participate in the reaction synergistically with the silane crosslinking agent during the vulcanization crosslinking process. At the same time, these functional groups can form chemical bonds with the surface of h-BN pretreated with a silane coupling agent, enhancing the interfacial bonding between the two phases, improving the buffering effect, and promoting the continuous conduction of heat flow.

[0103] Further, the RTV vulcanized silicone rubber modified with a silicone copolymer is prepared by mixing the silicone copolymer at 5% - 10% of the total amount of the RTV vulcanized silicone rubber and stirring for 10 - 20 min.

[0104] The modification principle is as follows: A silicone copolymer is introduced into the RTV vulcanized silicone rubber. This co-modifier not only has good flexibility and a low glass transition temperature, can adjust the network flexibility, and enhance the buffering and energy absorption, but also can form physical or weak chemical adsorption with h-BN due to its surface functionality, thereby optimizing the interfacial contact and improving the heat conduction performance.

[0105] Further, the RTV vulcanized silicone rubber modified with a difunctional chain extender is prepared by mixing the difunctional chain extender at 5% - 10% of the total amount of the RTV vulcanized silicone rubber and stirring at 60 - 80 °C for 15 - 30 min, where the difunctional chain extender is diallyl or dihydroxy PDMS.

[0106] The modification principle is as follows: By introducing a low-molecular-weight difunctional chain extender (diallyl or dihydroxy PDMS), the crosslinking density of the RTV vulcanization system is adjusted, the network rigidity is reduced, the elasticity and buffering energy absorption are increased. At the same time, the functional groups in the chain extender can react with the crosslinking system to form local flexible regions in the network. These regions with a lower crosslinking density contribute to improving the contact between h-BN and the matrix and the interfacial heat transfer.

[0107] Specific examples are provided below. The provided examples can enable those skilled in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0108] Example 1

[0109] 80 g of polyimide resin, 12 g of hexagonal boron nitride (1 - 10 μm), and 4 g of 3-aminopropyltriethoxysilane were added to 4 g of NMP. Using a high-shear mixer (2000 rpm), it was stirred for 15 minutes to form a homogeneous mixture. The mixture was uniformly coated on a PET release film using a doctor blade coater, with a target coating thickness of 30 μm. After coating, it was pre-dried in a ventilated drying chamber for 5 minutes, and then transferred to a curing furnace and cured at 300 °C for 45 minutes. After curing, the cured film was carefully peeled off from the PET release film to obtain a flat carrier layer.

[0110] 60 g of hexagonal boron nitride (10 - 50 μm) and 3 g of silane-coupled modified nano-silica powder were placed in a high-shear mixer and dry-mixed for 10 minutes. 35 g of RTV vulcanized silicone rubber was slowly added to the dry-mixed filler, and it was continuously stirred at high shear for 20 minutes to ensure that the filler and the rubber were fully and uniformly dispersed. 1 g of silicone oil was added to the mixing system and stirred for 5 minutes. 1 g of dibutyltin dilaurate was added and stirred for 5 minutes to ensure uniform dispersion. The mixed colloid was transferred to a vacuum degassing device and degassed for 10 minutes to remove air bubbles. Using a doctor blade coater, the degassed colloid was uniformly coated on the outside of the carrier layer, and the coating thickness was controlled to be 1.0 mm. After coating, it was left standing at 40 °C for 15 minutes for preliminary curing; then it was transferred to a curing furnace and cured at 100 °C for 45 minutes. After curing, it was naturally cooled to room temperature and placed at room temperature for 24 hours for full cross-linking to form a stable buffer layer.

[0111] In a high-shear mixer, 65 g of low-viscosity PDMS, 25 g of silicone resin, 7 g of hexagonal boron nitride (1 - 10 μm), 1 g of silane cross-linking agent, and 2 g of silicone oil were mixed and stirred for 15 minutes. Subsequently, the mixture was transferred to a vacuum degassing device and degassed for 10 minutes. Using a doctor blade coater, the degassed adhesive layer mixture was uniformly coated on the inside of the carrier layer, and the target coating thickness was controlled at 30 μm. After coating, it was left standing at 40 °C for 10 minutes to obtain the adhesive layer.

[0112] Example 2

[0113] The difference between this example and Example 1 is only that the matrix polymer is PDMS graft-modified with reactive functional groups, and its preparation process is as follows:

[0114] In a reaction kettle, 65 g of low-viscosity PDMS with Si-H active groups (low-viscosity PDMS) was added under nitrogen protection. 1.5 g of 3-aminopropyltriethoxysilane was slowly added. The reaction temperature was controlled at 100 °C, and the reaction time was set to 2 hours. This process achieved the grafting of PDMS terminal functional groups through a hydrosilylation reaction. After the reaction ended, the reaction solution was cooled to room temperature, and then filtered to remove unreacted silane and by-products, obtaining modified reactive PDMS.

[0115] The remaining components and process steps were the same as those in Example 1.

[0116] Example 3

[0117] The difference between this example and Example 1 was only that the preparation of the adhesive layer coating mixture adopted a co-blending and synergistic modification method, and the specific preparation process was as follows:

[0118] In a reaction kettle, under nitrogen protection, 65 g of low-viscosity PDMS and 1.5 g of epoxy group-containing silane (3-glycidoxypropyltrimethoxysilane) were pre-mixed at 40 °C for 30 minutes to allow partial reaction between the epoxy group-containing silane and PDMS, improving the polarity and interfacial activity of PDMS. The pre-mixed modified PDMS was transferred to a high-shear mixer, and 25 g of silicone resin was added and pre-stirred for 10 minutes to uniformly mix the two. 1 g of silane cross-linking agent, 2 g of silicone oil, and 7 g of silane-pretreated hexagonal boron nitride (particle size 1 - 10 μm) were added to the mixing system, and high-shear stirring was continued for 15 minutes to ensure full dispersion of each component. The mixing system was placed in a vacuum degassing device for vacuum degassing for 10 minutes to obtain a uniform modified adhesive layer mixture.

[0119] The remaining components and process steps were the same as those in Example 1.

[0120] Example 4

[0121] The difference between this example and Example 1 was only that the RTV vulcanized silicone rubber in the buffer layer was RTV vulcanized silicone rubber graft-modified with a silane coupling agent, and the thermal conductivity filler was hexagonal boron nitride treated with a silane coupling agent. The specific preparation process was as follows:

[0122] In a reaction kettle, under nitrogen protection, 35 g of RTV vulcanized rubber was added to the reaction kettle; 0.5 g of 3-aminopropyltriethoxysilane was added and mixed evenly; the temperature was raised to 90 °C, and the reaction was carried out for 1.5 hours under continuous stirring; after the reaction ended, the system was cooled to room temperature, and unreacted silane and low-molecular by-products were removed by filtration, obtaining RTV vulcanized silicone rubber graft-modified with a silane coupling agent.

[0123] 60 g of hexagonal boron nitride (particle size 10 - 50 μm) and 3-aminopropyltriethoxysilane (1 wt%, 0.6 g) were pre-dissolved in ethanol, stirred at room temperature for 30 minutes, then heat-treated (80 °C, 30 minutes) and dried to obtain silane-coupling-treated BN.

[0124] The remaining components and process steps were the same as in Example 1.

[0125] Example 5

[0126] The difference between this example and Example 1 was only that the RTV vulcanized silicone rubber in the buffer layer was RTV vulcanized silicone rubber modified with a silicone copolymer, and its preparation process was as follows:

[0127] In a high-shear mixer, 35 g of RTV vulcanized silicone rubber and 2.5 g of silicone copolymer were added together. Stirred at medium speed (1500 rpm) for 20 min until they were fully and evenly mixed to obtain a modified RTV system.

[0128] The remaining components and process steps were the same as in Example 1.

[0129] Example 6

[0130] The difference between this example and Example 1 was only that the RTV vulcanized silicone rubber in the buffer layer was RTV vulcanized silicone rubber modified with a difunctional chain extender, and its preparation process was as follows:

[0131] In a reaction kettle, 35 g of RTV vulcanized silicone rubber was added; 2.5 g of difunctional chain extender (diene-based PDMS) was added; stirred at 60 °C for 20 min for full mixing to form a difunctional chain extender-modified RTV system.

[0132] The remaining components and process steps were the same as in Example 1.

[0133] Comparative Example

[0134] Ordinary energy storage battery filled with buffer protection tape (9475 Battery Cushioning Tape, 3M)

[0135] The energy storage battery filled with buffer protection tape prepared in Examples 1 - 6 and the energy storage battery filled with buffer protection tape provided in the comparative example were tested as follows:

[0136] Adhesion test: The adhesion of the adhesive layer was measured by a peel test (N / 25 mm standard);

[0137] Buffer performance test: The energy absorption efficiency of the tape under impact load was measured by the drop hammer impact test method;

[0138] Thermal performance test: The thermal conductivity was measured at room temperature using the laser flash method.

[0139] The test data are shown in the following table:

[0140]

[0141] It can be seen that compared with the existing energy storage battery filled with buffer protection tape (comparative example), Examples 1-6 have obvious improvements in adhesion, buffer performance and thermal performance. Among them, Examples 2 and 4 show the best performance in adhesion and thermal performance respectively due to the use of PDMS graft modification and RTV functional graft modification processes; Example 6 uses a difunctional chain extender to modify the RTV system, and a good balance is also achieved in the comprehensive energy absorption effect and thermal conductivity. Generally speaking, the solutions of each example of the present invention can effectively improve the comprehensive performance of the energy storage battery filled with buffer protection tape, providing more efficient thermal management and safety protection for the battery system.

[0142] Principle description: The bearing layer provides dimensional stability and auxiliary thermal management. The polyimide resin in the bearing layer serves as a film-forming matrix, providing good mechanical properties. The thermal conductive filler can be selected from fine-grained hexagonal boron nitride or alumina to play an auxiliary heat dissipation role. The silane coupling agent can improve the interfacial bonding between the filler and the polyimide matrix; the adhesive layer has good initial adhesion and persistent adhesion to ensure tight bonding with the surface of the energy storage battery. At the same time, it can also provide a certain degree of thermal conductivity. The matrix polymer in the adhesive layer can be selected from low-viscosity PDMS or silicone rubber to form the main bonding matrix. The tackifier can be selected from silicone resins to improve the bonding performance of the adhesive layer. The thermal conductive filler is the same as the thermal conductive filler in the bearing layer, which can provide a certain degree of thermal conductivity without affecting the viscosity. The plasticizer can be selected from low-molecular-weight silicone oil to improve fluidity and flexibility; the buffer layer can play a buffering and filling role during battery installation, and at the same time can effectively conduct heat, thereby assisting the battery in heat dissipation. The RTV vulcanized silicone rubber in the buffer layer serves as a continuous phase, endowing the tape with flexibility and impact resistance. The selection of the thermal conductive filler is consistent with the other two layers, providing excellent thermal conductivity while maintaining electrical insulation. The particles can be selected as flakes or spheres, and the particle size is controlled within 10-50 μm, which is beneficial to form a thermal conduction network; the reinforcing filler is selected from silane-coupled modified ultrafine silicon powder to improve the mechanical strength and aging resistance of the tape, prevent filler agglomeration, and the plasticizer can be selected from low-molecular-weight silicone oil or other compatible plasticizers to adjust the flexibility of the tape and improve the processing fluidity. The catalyst can be selected from tin-based catalysts or platinum catalysts, which can promote the cross-linking and curing reaction of silicone rubber to ensure that the tape forms a stable three-dimensional network.

[0143] In this text, specific examples are used to illustrate the principles and implementation modes of the present invention. The description of the above embodiments is only for helping to understand the method of the present invention and its core idea. The above is only the preferred implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be within the protection scope of the present invention.

Claims

1. A filling buffer protection tape for an energy storage battery, characterized in that, It includes a carrier layer, an adhesive layer coated on the inner side of the carrier layer, and a buffer layer coated on the outer side of the carrier layer; by weight, the carrier layer is made of the following components: 70% - 85% of polyimide resin, 10% - 15% of heat-conducting filler, 2% - 5% of silane coupling agent, and the balance is solvent. The adhesive layer is made of the following components: 60% - 70% of matrix polymer, 20% - 30% of tackifying assistant, 5% - 10% of heat-conducting filler, 0.5% - 1.5% of crosslinking agent, and 2% - 5% of plasticizer. The buffer layer is made of the following components: 25% - 40% of RTV vulcanized silicone rubber, 55% - 70% of heat-conducting filler, 2% - 5% of reinforcing filler, 0.5% - 5% of plasticizer, and 0.5% - 1.5% of catalyst.

2. The energy storage battery filling buffer protection tape according to claim 1, characterized in that: The heat-conducting filler is hexagonal boron nitride; The solvent is NMP or DMF; The matrix polymer is low-viscosity PDMS; The tackifying assistant is silicone resin; The crosslinking agent is a silane crosslinking agent; The plasticizer is silicone oil; The reinforcing filler is silane coupling agent-modified nano-silicon powder; The catalyst is a tin-based catalyst or a platinum catalyst.

3. The energy storage battery filling buffer protection tape according to claim 1, characterized in that: The thickness of the carrier layer is 10 - 30 μm; The thickness of the adhesive layer is 20 - 50 μm; The thickness of the buffer layer is 0.5 - 2 mm; The particle size of the heat-conducting filler in the carrier layer and the adhesive layer is 1 - 10 μm; The particle size of the heat-conducting filler in the buffer layer is 10 - 50 μm.

4. A preparation method for preparing the energy storage battery filling buffer protection tape according to any one of claims 1 to 3, the preparation method comprising the following steps: S1: Add polyimide resin, heat-conducting filler and silane coupling agent into the solvent, and mix in a high-shear mixer for 10 - 15 min to form a mixed solution; S2: Use a doctor blade or casting technology to evenly coat the mixed solution on the release substrate, pre-dry it in a ventilated and dry environment after coating, and then place it in a curing furnace and cure it at 250 - 350 °C for 30 - 60 min; S3: Peel the cured film from the release substrate to obtain a flat carrier layer; S4: In a high-shear mixer, dry-mix the heat-conducting filler and the reinforcing filler for 5 - 10 min; S5: Slowly add RTV vulcanized silicone rubber to the dry-mixed and evenly mixed filler, and continue high-shear stirring for 15 - 20 min; S6: Add the plasticizer and continue stirring and mixing for 3 - 5 min; S7: Add the catalyst and continue stirring and mixing for 3 - 5 min; S8: Transfer the mixed colloid to a vacuum degassing device to degas for 5 - 10 min; S9: Use doctor blade coating or casting to evenly coat the degassed colloid on one side of the carrier layer; S10: Leave the carrier layer coated with the colloid to stand for 10 - 15 min at 30 - 40 °C, then send it into a thermal curing furnace. Set the temperature to 80 - 120 °C, cure for 30 - 60 min, then cool it naturally to room temperature and leave it to stand for 20 - 24 h to obtain the buffer layer; S11: Mix the matrix polymer, tackifying aid, thermal conductivity filler, crosslinking agent and plasticizer, and then use a high-shear stirring device to stir for 10 - 15 min. After that, place the mixture in a vacuum degassing device and degas for 5 - 10 min; S12: Adopt a doctor blade or casting technology to coat the degassed mixture on the other side of the carrier layer. After coating, leave it to stand for 10 - 5 min at 30 - 40 °C to obtain the adhesive layer.

5. The preparation method according to claim 4, characterized in that, In step S11, the matrix polymer is PDMS graft-modified with reactive functional groups, the tackifying aid is a silicone resin type, the thermal conductivity filler is hexagonally boron nitride modified with silane, and the preparation process of the low-viscosity PDMS graft-modified with reactive functional groups includes the following steps: Under an inert atmosphere, place the low-viscosity PDMS into a reaction kettle, where the low-viscosity PDMS is PDMS containing Si-H active groups; Add a silane coupling agent, control the reaction temperature at 80 - 120 °C, and react for 1 - 3 h, where the silane coupling agent is vinyltriethoxysilane or 3-aminopropyltriethoxysilane; After the reaction ends, cool the reaction solution to room temperature, and filter or rectify to remove the unreacted silane and by-products to obtain the modified PDMS.

6. The preparation method according to claim 4, characterized in that, Step S11 specifically includes the following sub-steps: S111: In a reaction kettle, premix the epoxy group silane and the matrix polymer at 40 - 60 °C and react for 15 - 30 min, where the matrix polymer is low-viscosity PDMS; S112: Mix the premixed modified PDMS with the tackifying aid and pre-stir in a high-shear mixer for 5 - 10 minutes, where the tackifying aid is a silicone resin type; S113: Add the crosslinking agent, plasticizer and the thermally conductive filler pretreated with silane, and continue to stir for 10 - 15 min, where the crosslinking agent is a silane crosslinking agent, the plasticizer is silicone oil, and the thermally conductive filler is hexagonal boron nitride; S114: Place the mixed system in a vacuum degassing device and degas for 5 - 10 min to obtain the modified mixture.

7. According to the preparation method described in claim 4, characterized in that: In step S5, the RTV vulcanized silicone rubber is RTV vulcanized silicone rubber graft-modified with a silane coupling agent, and the thermal conductivity filler is hexagonal boron nitride treated with a silane coupling agent; Or the RTV vulcanized silicone rubber is RTV vulcanized silicone rubber modified with a silicone copolymer; Or the RTV vulcanized silicone rubber is RTV vulcanized silicone rubber modified with a bifunctional chain extender.

8. The preparation method according to claim 7, wherein The preparation process of the RTV vulcanized silicone rubber graft-modified with a silane coupling agent includes the following steps: Under an inert atmosphere, mix the RTV vulcanized rubber with a silane coupling agent, where the silane coupling agent is 3-aminopropyltriethoxysilane; Heat to 80 - 100 °C and react for 1 - 2 h under stirring conditions. After the reaction is completed, cool the system to room temperature, filter to remove unreacted substances or low-molecular by-products to obtain the product.

9. The preparation method according to claim 7, characterized in that, The RTV vulcanized silicone rubber modified by the silicone copolymer is prepared by mixing the silicone copolymer with the RTV vulcanized silicone rubber at 5% - 10% of the total amount of the RTV vulcanized silicone rubber and stirring for 10 - 20 min.

10. The preparation method according to claim 7, wherein The RTV vulcanized silicone rubber modified by the bifunctional chain extender is prepared by mixing the bifunctional chain extender with the RTV vulcanized silicone rubber at 5% - 10% of the total amount of the RTV vulcanized silicone rubber and stirring at 60 - 80 °C for 15 - 30 min, wherein the bifunctional chain extender is diallyl or dihydroxy PDMS.

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