A thermally conductive silicone sheet for energy storage battery buffering, shock absorption and preparation method thereof

Abstract

The present application relates to the technical field of silicone materials, and more specifically, it relates to a heat-conducting silicone sheet for buffering, shock absorption and heat conduction used in energy storage batteries and a preparation method thereof. It is prepared from the following raw materials in weight percentage: 1-5% cross-linking agent, 0.01-0.3% catalyst, 0-2% color powder, 30-90% expanded graphite, and the remainder is silicone oil. Expanded graphite has better resilience and thermal conductivity. Under the action of cross-linking agent and catalyst, silicone oil forms macromolecular silicone rubber with good elasticity and flexibility, and the expanded graphite is coated to form a heat-conducting silicone sheet with better elasticity and thermal conductivity. When used in energy storage batteries of new energy vehicles, it has better heat dissipation effect and buffering effect, reducing the possibility of damage.

Description

Technical Field

[0001] The present application relates to the technical field of silicone materials, and more specifically, to a silicone sheet for buffering, shock absorption and heat conduction used in energy storage batteries and a preparation method thereof. Background Art

[0002] Energy storage batteries refer to batteries that convert chemical energy into electrical energy and have energy storage functions. Energy storage batteries can store electrical energy in the battery when charging, and then release the stored electrical energy when needed to meet power needs. Energy storage batteries usually use rechargeable battery technology, such as lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, etc.

[0003] The main application areas of energy storage batteries include: power system energy storage, transportation energy storage, distributed energy storage, and electronic equipment storage. Energy storage batteries are a very important energy storage technology that can improve energy utilization efficiency, promote the application of clean energy, and reduce carbon emissions. They are of great significance to future energy transformation and sustainable development.

[0004] However, energy storage batteries are prone to dissipate heat during use, especially the heat dissipation of energy storage batteries in new energy vehicles. Currently, the thermal conductive sheets used for heat dissipation of energy storage batteries in new energy vehicles include PI thermal conductive sheets, polyurethane thermal conductive sheets, acrylic thermal conductive sheets, silicone thermal conductive sheets, etc. Among them, the heat resistance of polyurethane heat dissipation films and acrylic heat dissipation films is not good, and the PI heat dissipation film is hard and easy to crack; thermal conductive silicone sheets have better heat resistance and softness, and are not easy to crack or heat deform during use. Therefore, thermal conductive silicone sheets are widely used in the heat dissipation of energy storage batteries in new energy vehicles.

[0005] However, in order to obtain higher thermal conductivity, a large amount of inorganic thermal conductive fillers such as graphene, diamond powder, hexagonal boron nitride, carbon nanotubes, etc. are added to the thermal conductive silicone sheet. As the amount added increases, the heat dissipation performance of the thermal conductive silicone sheet increases, but it also leads to a decrease in the mechanical properties of the thermal conductive silicone sheet, such as a decrease in elasticity, which leads to a decrease in the buffering effect of the thermal conductive silicone sheet. When used in energy storage batteries for new energy vehicles, it is prone to breakage, so further research is needed. Summary of the invention

[0006] In order to obtain better heat dissipation and buffering performance, the present application provides a thermally conductive silicone sheet for buffering, shock absorption and thermal conductivity of energy storage batteries and a preparation method thereof.

[0007] In a first aspect, the present application provides a buffering, shock-absorbing and thermally conductive silicone sheet for energy storage batteries, which is made of the following raw materials in percentage by weight:

[0008] Crosslinking agent 1-5%

[0009] Catalyst 0.01-0.3%

[0010] Color powder 0-2%

[0011] Expanded graphite 30-90%

[0012] The balance is silicone oil.

[0013] In the above scheme, silicone oil forms macromolecular silica gel under the action of cross-linking agent and catalyst, and its molecules have good elasticity and flexibility, and can easily cover expanded graphite.

[0014] Compared with graphene, diamond powder, hexagonal boron nitride and carbon nanotubes, expanded graphite has better softness, a worm-like structure, certain elasticity and better thermal conductivity. Therefore, when expanded graphite is filled in silicone, the resulting thermally conductive silicone sheet has both better thermal conductivity and elasticity.

[0015] In summary, by filling expanded graphite in silicone oil and in the presence of a catalyst and a cross-linking agent, after calendering and aging, the thermally conductive silicone sheet formed has better thermal conductivity and elasticity. When used in the energy storage battery of new energy vehicles, it has better heat dissipation and buffering effects.

[0016] The thermal conductivity of the thermally conductive silicone sheet of the present application is 4-7W / MK (test sample thickness 3mm), Young's modulus 15-30Psi (test sample thickness 1.5mm), and elongation 60-85% (test sample thickness 1.5mm).

[0017] Preferably, the expanded graphite is composed of the following raw materials in parts by weight:

[0018] 3-5 parts of expanded graphite with a particle size of 5-10μm

[0019] Particle size is 12-20μm Expanded graphite 1.2-1.9 parts

[0020] The particle size is 21-30μm and the expanded graphite is 0.6-1.9 parts.

[0021] In the above technical scheme, the expanded graphite with different particle size ranges is used and compounded in different dosage ratios, so that the expanded graphites with different particle sizes are interlocked with each other, and the contact area between the particles is increased, so that it has both fluffy feeling and filling uniformity, and then compounded with silicone oil, cross-linking agent and catalyst. The macromolecular silica gel obtained by cross-linking and curing tightly wraps the expanded graphite, and the formed thermally conductive silicone sheet has better thermal conductivity and elasticity. The thermally conductive silicone sheet is used in the energy storage battery of new energy vehicles, which plays a better heat dissipation and buffering role, reducing the possibility of damage.

[0022] Preferably, the worm length of the expanded graphite is 50-100 μm; the pore size of the expanded graphite is 100-500 nm.

[0023] The worm length and pore range of the above expanded graphite are both within the preferred range of the present application. The expanded graphite with the above worm length and pore range is filled into the raw material system of the thermally conductive silicone sheet, so that the prepared thermally conductive silicone sheet has both better thermal conductivity and elasticity.

[0024] Preferably, the expanded graphite is modified expanded graphite, and the modified expanded graphite is prepared by the following method:

[0025] Expanded graphite 20.4-34 parts

[0026] 1-3 parts of hydroxy acrylate

[0027] Long chain acrylate silane 0.8-1.5 parts

[0028] Vegetable oil acrylate 0.5-1.8 parts

[0029] Initiator 0.1-0.3 parts

[0030] 30-50 parts of solvent.

[0031] Modified expanded graphite is prepared by the following method:

[0032] According to weight parts, hydroxy acrylate, vegetable oil acrylate and solvent are weighed and put into a reaction kettle, heated to 60-80°C, and then an initiator is added to react for 0.5-1h, and then long-chain acrylate silane is added to continue the reaction for 1-2h to form a macromolecular polymer complex; then expanded graphite is added, mixed evenly, vacuum distilled, the solvent is removed, and dried to obtain modified expanded graphite.

[0033] The surface of expanded graphite is inert and has poor compatibility with polymers, thereby reducing the bonding stability between expanded graphite and polymer molecules.

[0034] Therefore, the hydroxy acrylate and vegetable oil acrylate used have flexibility after film formation, and can further react with long-chain acrylate silane to form a macromolecular cross-linked network composite, and the macromolecular cross-linked network composite contains siloxy groups, is stably bonded to expanded graphite, and forms a tightly coated film on the surface of expanded graphite to obtain modified expanded graphite, and the modified expanded graphite is easily filled into the polymer, so that the obtained thermally conductive silicone sheet has both better thermal conductivity and elasticity, and plays a better buffering role, avoiding the possibility of damage during the heat dissipation of energy storage batteries used in new energy vehicles.

[0035] Preferably, the vegetable oil acrylate is epoxidized soybean oil acrylate oligomer.

[0036] Epoxidized soybean oil acrylate oligomer can play a role in better film-forming softness, wettability and adhesion, and the macromolecular cross-linked network complex formed by the reaction with hydroxy acrylate and long-chain acrylate silane has better film-forming property, adhesion and compatibility with polymers, so it is easy to coat the expanded graphite, so that the raw material system of the modified expanded graphite and the thermal conductive silicone sheet is fully mixed and uniform, and the prepared silicone rubber is compatible with the modified expanded graphite and connected tightly, which further improves the elasticity and thermal conductivity of the thermal conductive silicone sheet, and plays a better buffering and heat dissipation role, reducing the occurrence of cracks during use.

[0037] Preferably, the hydroxy acrylate is one or more of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, and 2-propylheptyl methacrylate.

[0038] 1,4-Butanediol dimethacrylate, ethylene glycol dimethacrylate, and 2-propylheptyl methacrylate all contain multiple functional groups, can undergo self-crosslinking, and can further react with vegetable oil acrylates and long-chain acrylate silanes to form a cross-linked network of macromolecular complexes, which in turn have better coating properties on the surface of expanded graphite, making it easy to fully and evenly mix with the raw material system of the thermally conductive silicone sheet. The resulting thermally conductive silicone sheet has both good thermal conductivity and elasticity, and when used in energy storage batteries for new energy vehicles, it has better heat dissipation and buffering effects.

[0039] When 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate and 2-propylheptyl methacrylate are compounded, the formed coating film has better softness and coating properties. When the modified graphite is used to produce thermally conductive silicone sheets, the thermally conductive silicone sheets can further obtain better thermal conductivity and elasticity. Therefore, when used in energy storage batteries for new energy vehicles, they have better heat dissipation and buffering effects, reducing the possibility of damage during use.

[0040] Preferably, the long alkacrylate chain silicon is one or more of 3-(methoxydimethylsilyl)propyl acrylate, 3-[tri(acetyloxy)silyl]propyl 2-methyl-2-acrylate, 3-(diethoxymethylsilyl)propyl 2-acrylate, and bis-3-methacryloxypropylated tetramethyldisiloxane.

[0041] 3-(Methoxydimethylsilyl)propyl acrylate, 3-[tri(acetyloxy)silyl]propyl 2-methyl-2-acrylate, 3-(diethoxymethylsilyl)propyl 2-acrylate, and bis-3-methacryloxypropylated tetramethyldisiloxane all contain acrylate groups and silanes, can undergo self-polymerization, and can further react with hydroxy acrylates and vegetable oil acrylates to form a well-adhered cross-linked network macromolecular complex. After surface modification of expanded graphite, it is filled into the raw material system of the thermally conductive silicone sheet, so that the prepared thermally conductive silicone sheet has both better thermal conductivity and ejection, and has better heat dissipation and buffering effects during use, reducing the possibility of damage.

[0042] Preferably, the silicone oil is at least two of methyl silicone oil, ethyl silicone oil, hydroxy silicone oil, amino silicone oil, hydrogen-containing silicone oil, and polyether-modified silicone oil.

[0043] At least two of the above silicone oils are selected for compounding, and the formed silicone rubber has better elasticity and better coating effect on expanded graphite, so that the thermally conductive silicone sheet obtained has better thermal conductivity and elasticity and plays a better buffering role.

[0044] Preferably, the crosslinking agent is one or more of vinyltrimethoxysilane, vinyltributylonoximesilane, and propyltriacetoxysilane, and the catalyst is a platinum catalyst.

[0045] The above cross-linking agent and catalyst are preferably selected in this application, and combined with the silicone oil and expanded graphite of this application, the thermally conductive silicone sheet prepared has both better thermal conductivity and buffering performance.

[0046] In a second aspect, the present application provides a method for preparing a buffering, shock-absorbing and thermally conductive silicone sheet for energy storage batteries, comprising the following steps:

[0047] According to the weight percentage, the silicone oil, the cross-linking agent and the catalyst are weighed and mixed evenly, and then the color powder and the expanded graphite are added, mixed evenly, vacuumed, calendered, and aged to obtain a thermally conductive silicone sheet.

[0048] After the silicone oil, cross-linking agent and catalyst are evenly mixed, the color powder and expanded graphite are added. After the mixture is evenly mixed, vacuuming, calendering and aging are carried out to obtain a thermally conductive silicone sheet with stable structure, good thermal conductivity and good elasticity.

[0049] In summary, this application has the following beneficial effects:

[0050] 1. Since the present application uses silicone oil under the action of a cross-linking agent and a catalyst to form a macromolecular silicone rubber with good elasticity and flexibility, and then by adding expanded graphite with good thermal conductivity and flexibility, the silicone rubber is coated on the expanded graphite, and the formed thermally conductive silicone sheet has good thermal conductivity and elasticity. When used in the energy storage battery of new energy vehicles, it plays a better buffering and heat dissipation role, reducing the possibility of damage.

[0051] 2. Use the expanded graphite with different particle size ranges mentioned above and compound them in different dosage ratios so that the expanded graphite with different particle sizes can be interlocked with each other, and the contact area between the particles is increased, so that it has both fluffy feeling and filling uniformity. Then compound it with silicone oil, cross-linking agent and catalyst. The macromolecular silica gel obtained by cross-linking and curing will tightly wrap the expanded graphite. The formed thermally conductive silicone sheet has better thermal conductivity and elasticity. The thermally conductive silicone sheet is used in the energy storage battery of new energy vehicles, which plays a better heat dissipation and buffering role, reducing the possibility of breakage.

[0052] 3. The hydroxy acrylate and vegetable oil acrylate used have flexibility after film formation, and can further react with long-chain acrylate silane to form a macromolecular cross-linked network complex. The macromolecular cross-linked network complex contains siloxy groups, is stably bonded to expanded graphite, and forms a tightly wrapped coating film on the surface of expanded graphite to obtain modified expanded graphite. The modified expanded graphite is easily filled into the polymer, so that the obtained thermally conductive silicone sheet has better heat dissipation effect and elasticity, plays a better buffering role, and avoids the possibility of damage during the heat dissipation of energy storage batteries used in new energy vehicles. DETAILED DESCRIPTION

[0053] The present application is further described in detail below with reference to the embodiments.

[0054] The sources of some raw materials;

[0055] Table 1 Sources or parameters of some raw materials

[0056]

[0057] Example

[0058] Example 1

[0059] A thermally conductive silicone sheet for buffering, shock absorption and application in energy storage batteries is prepared by the following method:

[0060] Weigh 5kg of ethyl silicone oil, 1.497kg of hydrogen-containing silicone oil, 0.5kg of cross-linking agent, and 0.003kg of catalyst, and put them into a stirring device in sequence. Mix them at a speed of 100r / min for 30min, then add 3kg of expanded graphite, and continue stirring for 20min. The obtained material is then transferred to a vacuum degassing machine for vacuum degassing, and calendered by a calender, and kept at a constant temperature at 150°C for 30min to obtain a thermally conductive silicone sheet.

[0061] The cross-linking agent is vinyl trimethoxysilane; the catalyst is a platinum catalyst; the particle size of the expanded graphite is 5 μm, the worm length of the expanded graphite is 50 μm; and the average pores of the expanded graphite are about 100 nm.

[0062] Example 2

[0063] The difference between Example 2 and Example 1 is that the buffering, shock-absorbing and heat-conducting silicone sheet for energy storage batteries is prepared by the following method:

[0064] Weigh 1.2 kg of ethyl silicone oil, 0.8 kg of polyether modified silicone oil, 0.3 kg of amino silicone oil, 0.498 kg of hydrogenated silicone oil, 0.3 kg of cross-linking agent, and 0.002 kg of catalyst, and put them into a stirring device in turn. Mix them at a speed of 100 r / min for 30 minutes. Then add 0.2 kg of color powder and 6.8 kg of expanded graphite, and continue stirring for 20 minutes. The obtained material is then transferred to a vacuum degassing machine for vacuum degassing, and calendered by a calendering machine. It is kept at a constant temperature at 150°C for 30 minutes to obtain a thermally conductive silicone sheet.

[0065] The cross-linking agent is vinyl trimethoxysilane; the catalyst is a platinum catalyst; the particle size of the expanded graphite is 5 μm, the worm length of the expanded graphite is 80 μm; and the average pores of the expanded graphite are about 200 nm.

[0066] Example 3

[0067] The difference between Example 3 and Example 1 is that the buffering, shock-absorbing and heat-conducting silicone sheet for energy storage batteries is prepared by the following method:

[0068] Weigh 0.3 kg of ethyl silicone oil, 0.2 kg of methyl silicone oil, 0.1 kg of hydroxy silicone oil, 0.099 kg of hydrogenated silicone oil, 0.1 kg of cross-linking agent, 0.001 kg of catalyst, and 9 kg of expanded graphite, and put them into a stirring device in sequence. Mix them at a speed of 100 r / min for 30 minutes, then add 0.2 kg of color powder and 6.8 kg of expanded graphite, and continue stirring for 20 minutes. The obtained material is then transferred to a vacuum degassing machine for vacuum degassing, and calendered by a calender, and kept at a constant temperature at 150° C. for 30 minutes to obtain a thermally conductive silicone sheet.

[0069] The cross-linking agent is vinyl trimethoxysilane; the catalyst is a platinum catalyst; the particle size of the expanded graphite is 5 μm, the worm length of the expanded graphite is 100 μm; and the average pore of the expanded graphite is about 500 nm.

[0070] Example 4

[0071] The difference between Example 4 and Example 2 is that the particle size of the expanded graphite is 12 μm.

[0072] Example 5

[0073] The difference between Example 5 and Example 2 is that the particle size of the expanded graphite is 21 μm.

[0074] Example 6

[0075] The difference between Example 6 and Example 2 is that the expanded graphite is composed of 3 kg of expanded graphite with a particle size of 6 μm, 1.9 kg of expanded graphite with a particle size of 12 μm, and 1.9 kg of expanded graphite with a particle size of 21 μm.

[0076] Example 7

[0077] The difference between Example 7 and Example 2 is that the expanded graphite is composed of 4 kg of expanded graphite with a particle size of 6 μm, 1.8 kg of expanded graphite with a particle size of 12 μm, and 1 kg of expanded graphite with a particle size of 26 μm.

[0078] Example 8

[0079] The difference between Example 8 and Example 2 is that the expanded graphite is composed of 5 kg of expanded graphite with a particle size of 6 μm, 1.2 kg of expanded graphite with a particle size of 20 μm, and 0.6 kg of expanded graphite with a particle size of 30 μm.

[0080] Example 9

[0081] The difference between Example 9 and Example 6 is that the expanded graphite with a particle size of 30 μm is replaced by an equal amount of expanded graphite with a particle size of 12 μm.

[0082] Example 10

[0083] The difference between Example 10 and Example 6 is that the expanded graphite with a particle size of 12 μm is replaced by an equal amount of expanded graphite with a particle size of 6 μm.

[0084] Embodiment 11

[0085] The difference between Example 11 and Example 7 is that the expanded graphite is modified expanded graphite, and the modified expanded graphite is prepared by the following method:

[0086] Weigh 1kg of hydroxy acrylate, 1.8kg of vegetable oil acrylate, and 30kg of solvent into a reactor, start the stirring device, stir at a rate of 100r / min, heat to 70°C, add 0.1kg of initiator, react for 0.8h, add 0.8kg of long-chain acrylate silane and continue to react for 1h to obtain a macromolecular polymer complex, add and mix at a speed of 200r / min for 30min to fully mix, then add 12kg of 6μm expanded graphite, 5.4kg of 12μm expanded graphite, and 3kg of 26μm expanded graphite respectively, mix well, stir for 30min, and then perform reduced pressure distillation at a temperature of 120°C for about 30min. The pressure gauge shows -0.1MPa, the solvent is completely removed, and then placed in an oven at 80°C for drying for 2h to obtain modified expanded graphite.

[0087] Among them, the vegetable oil modified acrylate is epoxy soybean oil acrylate oligomer; the hydroxy acrylate is 1,4-butanediol dimethacrylate; the long alkane acrylate chain silicon is bis-3-methacryloxypropylated tetramethyldisiloxane; the solvent is ethyl acetate, and the initiator is tert-butyl peroxybenzoate.

[0088] Example 12

[0089] The difference between Example 12 and Example 11 is that the amounts of raw materials used are different, specifically as follows: 2 kg hydroxy acrylate, 1.3 kg vegetable oil acrylate, 0.2 kg initiator, 1.2 kg long-chain acrylate silane, 40 kg solvent, 16 kg 6 μm expanded graphite, 7.2 kg expanded graphite with a particle size of 12 μm, and 4 kg expanded graphite with a particle size of 26 μm.

[0090] Embodiment 13

[0091] The difference between Example 13 and Example 11 is that the amounts of raw materials used are different, specifically as follows: 3 kg hydroxy acrylate, 0.5 kg vegetable oil acrylate, 0.3 kg initiator, 1.8 kg long-chain acrylate silane, 50 kg solvent, 20 kg 6 μm expanded graphite, 9 kg expanded graphite with a particle size of 12 μm, and 5 kg expanded graphite with a particle size of 26 μm.

[0092] Embodiment 14

[0093] The difference between Example 14 and Example 12 is that the hydroxy acrylate is composed of 1 kg 1,4-butanediol dimethacrylate, 0.5 kg ethylene glycol dimethacrylate, and 0.5 kg 2-propylheptyl methacrylate.

[0094] Embodiment 15

[0095] The difference between Example 15 and Example 14 is that the long alkacrylate chain silicon is composed of 0.5 kg of 3-(methoxydimethylsilyl)propyl acrylate and 0.7 kg of bis-3-methacryloxypropylated tetramethyldisiloxane.

[0096] Example 16

[0097] The difference between Example 16 and Example 11 is that an equal amount of long-chain acrylate silane is replaced by hydroxy acrylate.

[0098] Embodiment 17

[0099] The difference between Example 17 and Example 11 is that an equal amount of long-chain acrylate silane is replaced by hydroxy acrylate.

[0100] Embodiment 18

[0101] The difference between Example 18 and Example 11 is that the vegetable oil acrylate is replaced by hydroxy acrylate in equal amounts.

[0102] Embodiment 19

[0103] The difference between Example 19 and Example 11 is that the vegetable oil acrylate and hydroxy acrylate are replaced by long-chain acrylate silane in equal amounts.

[0104] Embodiment 20

[0105] The difference between Example 20 and Example 11 is that hydroxy acrylate is replaced by acrylic acid.

[0106] Embodiment 21

[0107] The difference between Example 21 and Example 11 is that the long-chain acrylate silane is replaced by silane coupling agent KH550.

[0108] Comparative Example

[0109] Comparative Example 1

[0110] The difference between Comparative Example 1 and Example 1 is that the expanded graphite is replaced by graphene in equal amounts.

[0111] Comparative Example 2

[0112] The difference between Comparative Example 2 and Example 1 is that the expanded graphite is replaced by carbon nanotubes in equal amounts.

[0113] Comparative Example 3

[0114] The difference between Comparative Example 3 and Example 1 is that the expanded graphite is replaced by aluminum oxide in equal amounts.

[0115] Comparative Example 4

[0116] The difference between Comparative Example 4 and Example 1 is that the particle size of the expanded graphite is 50 μm.

[0117] Performance testing

[0118] The thermally conductive silicone sheets obtained in Examples 1-22 and Comparative Examples 1-4 were used to prepare test samples, and the following performance tests were performed, as shown in Table 2.

[0119] Detection method / test method

[0120] 1. Young's modulus

[0121] Young's modulus, also known as elastic modulus or elastic constant, is a physical quantity that describes the ability of a solid material to resist deformation when subjected to external force. For elastic materials such as silicone rubber, a lower Young's modulus means that it is more likely to deform when subjected to force, and also has better elastic recovery ability, and thus the buffering effect of silicone rubber is better. The test sample thickness is 1.5mm; the test method refers to GB / T 13322-1991.

[0122] 2. Elongation

[0123] The elongation of silicone rubber is its ability to deform under tension. The higher the elongation of silicone rubber, the better its elasticity, the stronger its deformation ability, and the better its cushioning effect. The thickness of the test sample is 1.5mm, and the test method refers to GB / T528-2009.

[0124] 1. Thermal conductivity

[0125] The thermal conductivity is tested according to ASTM D5470, and the test sample thickness is 3 mm.

[0126] The above experiments were tested three times and the average values ​​were taken. The specific values ​​are shown in Table 2;

[0127] Table 2 Experimental data of Examples 1-22 and Comparative Examples 1-4

[0128]

[0129]

[0130] Combining Example 1 and Comparative Examples 1-4 and Table 2, it can be seen that the thermal conductivity and Young's modulus of Comparative Examples 1-2 are higher than those of Example 1, while the elongation is lower than that of Example 1; while the Young's modulus of Comparative Examples 3-4 is higher than that of Example 1, and the elongation and thermal conductivity of Comparative Examples 3-4 are lower than those of Example 1, indicating that the raw material composition of the present application has a better thermal conductivity effect and better elasticity, and the particle size range of the expanded graphite of the present application is better, so that the thermally conductive silicone sheet has better elasticity and thermal conductivity, and the obtained thermally conductive silicone rubber is used in the energy storage battery of new energy vehicles to play a better buffering and heat dissipation role.

[0131] Combining Example 2 and Example 6-8 and Table 2, it can be seen that the Young's modulus of Example 6-8 is lower than that of Example 2, and the elongation and thermal conductivity of Comparative Example 6-8 are higher than those of Example 2; it shows that the three expanded graphites with different particle sizes of the present application are compounded to be interlocked with each other, and then compounded with silicone oil, a cross-linking agent, and a catalyst. The thermally conductive silicone sheet obtained by cross-linking and curing has better thermal conductivity and elasticity, and the thermally conductive silicone sheet is used in the energy storage battery of new energy vehicles, which has better heat dissipation and buffering effect, and reduces the possibility of breakage.

[0132] Combining Example 7 and Example 11-13 and Table 2, it can be seen that the Young's modulus of Example 11-13 is lower than that of Example 7, and the elongation and thermal conductivity of Example 11-13 are higher than those of Example 7; it can be seen that after the composite reaction of hydroxy acrylate, vegetable oil acrylate and long-chain acrylate silane, the surface modification of expanded graphite can be compared, and the modified expanded graphite obtained is used in the raw material system of the thermally conductive silicone sheet, so that the thermally conductive silicone sheet has both better thermal conductivity and buffering effect.

[0133] Combining Example 12 and Example 14 and Table 2, it can be seen that the Young's modulus of Example 11 is higher than that of Example 14, and the elongation and thermal conductivity of Example 11 are lower than those of Example 14, indicating that the compounding of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, and 2-propylheptyl methacrylate plays a synergistic role, thereby making the thermal conductivity, elasticity, and buffering performance of the thermally conductive silicone rubber sheet better.

[0134] Combining Example 14 and Example 15 with Table 2, it can be seen that the Young's modulus of Example 14 is higher than that of Example 15, and the elongation and thermal conductivity of Example 15 are lower than those of Example 14; this indicates that the use of 3-(methoxydimethylsilyl)propyl acrylate and bis-3-methylpropyleneoxypropylated tetramethyl disiloxane for compounding has a synergistic effect, and thus the thermally conductive silicone rubber sheet produced by the modified expanded graphite has both better thermal conductivity and elasticity, and thus when used in the energy storage battery of new energy vehicles, it has a better heat dissipation effect and buffering effect.

[0135] Combining Example 11 and Examples 16-21 with Table 2, it can be seen that the Young's modulus of Examples 16-21 is higher than that of Example 11, and the elongation and thermal conductivity of Examples 16-21 are lower than that of Example 11; this indicates that the compounding of the vegetable oil acrylate, hydroxy acrylate, and long-chain acrylate silane of the present application plays a better role, thereby making the thermal silicone rubber sheet have better thermal conductivity and elasticity.

[0136] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A thermally conductive silicone sheet for energy storage battery buffering, shock absorption, and heat conduction, characterized in that: Made from the following raw materials in weight percentage: Crosslinking agent 1-5% Catalyst 0.01-0.3% Color powder 0-2% Modified expanded graphite 30-90% The balance is silicone oil; The modified expanded graphite is prepared from the following raw materials: Expanded graphite 20.4-34 parts 1-3 parts of hydroxy acrylate Long chain acrylate silane 0.8-1.5 parts Vegetable oil acrylate 0.5-1.8 parts Initiator 0.1-0.3 parts 30-50 parts of solvent; The expanded graphite is composed of the following raw materials in parts by weight: 3-5 parts of expanded graphite with a particle size of 5-10μm Particle size is 12-20μm Expanded graphite 1.2-1.9 parts 0.6-1.9 parts of expanded graphite with a particle size of 21-30 μm; The vegetable oil acrylate is epoxy soybean oil acrylate; the hydroxy acrylate is one or more of 1,4-butanediol dimethacrylate, ethylene glycol dimethacrylate, and 2-propylheptyl methacrylate; the long-chain acrylate silane is 3-(methoxydimethylsilyl)propyl acrylate and / or bis-3-methacryloxypropylated tetramethyldisiloxane; the silicone oil is at least two of methyl silicone oil, ethyl silicone oil, hydroxy silicone oil, amino silicone oil, hydrogen-containing silicone oil, and polyether-modified silicone oil, one of which is hydrogen-containing silicone oil; the crosslinking agent is vinyl trimethoxysilane or vinyl trisbutyl oxime silane, and the catalyst is a platinum catalyst.

2. The thermally conductive silicone sheet for buffering, shock absorption and heat conduction used in energy storage batteries according to claim 1, characterized in that: The worm length of the expanded graphite is 50-100 μm; the pores of the expanded graphite are 100-500 nm.

3. A method for preparing a buffering, shock-absorbing and thermally conductive silicone sheet for energy storage batteries according to claim 1 or 2, characterized in that: The following steps are involved: According to the weight percentage, silicone oil, cross-linking agent and catalyst are weighed and mixed evenly, and then color powder and modified expanded graphite are added, mixed evenly, vacuumed, calendered, and aged to obtain a thermally conductive silicone sheet.

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