A lithium ion battery pack heat dissipation protection structure

Abstract

The application discloses a lithium ion battery pack heat dissipation protection structure, which comprises a protection frame body, a rectangular frame formed by an end plate and a side plate, and a battery pack comprising a plurality of battery monomers arranged in the protection frame body in sequence; wherein the end plate and the side plate each comprise an outer protection layer, a temperature-resistant heat dissipation layer and an energy-absorbing buffer layer arranged in sequence; the temperature-resistant heat dissipation layer is provided with a plurality of heat dissipation grooves arranged side by side and spaced apart, the inner wall of the heat dissipation groove is provided with a pressure relief port in communication with the outside, the pressure relief port is outwardly inclined, a spherical air bag body is installed in the heat dissipation groove, part of the spherical surface of the spherical air bag body extends to the outside of the heat dissipation groove and is embedded in the energy-absorbing buffer layer, and the spherical air bag body is filled with heat-absorbing liquid. The heat dissipation protection structure formed by the special end plate and the side plate provides a firm support structure for the battery pack, effectively prevents external impact from damaging the battery pack, and has a good heat dissipation effect on the battery pack.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and more specifically to a heat dissipation protection structure for lithium-ion battery packs. Background Technology

[0002] In electric vehicles, portable electronic devices, and large-scale energy storage systems, lithium-ion battery packs have become the preferred energy storage solution due to their high energy density and long cycle life. However, with the rapid development of lithium-ion battery technology and the continuous expansion of its applications, the safety of battery packs is receiving increasing attention. Existing lithium-ion battery packs do indeed have some significant problems in their design and use. These problems not only affect battery performance and lifespan but may also cause safety accidents, posing serious harm to users and the environment.

[0003] First, many lithium-ion battery packs lack effective support structures. Under external impact or pressure, the batteries are prone to deformation or damage, leading to internal short circuits, a potential factor causing battery pack fires or even explosions. Second, battery packs generate a large amount of heat during charging and discharging. Inadequate heat dissipation can cause the battery temperature to rise continuously, triggering thermal runaway, which not only reduces battery performance but also greatly increases the risk of fire and explosion. Furthermore, existing battery pack designs often neglect energy absorption, meaning they lack sufficient cushioning capacity in the event of a collision, failing to effectively protect battery cells and avoid or reduce impact damage.

[0004] To address the above issues, developing a protective structure for lithium-ion battery packs with excellent heat dissipation and efficient energy absorption is crucial. This protective structure should provide robust support, reducing direct damage to the battery from external impacts. Simultaneously, through efficient heat dissipation design, it should ensure the battery pack maintains a suitable operating temperature under high load conditions, thereby preventing thermal runaway. Furthermore, optimized energy absorption design should also be considered to improve the battery pack's safety performance in collision scenarios. These comprehensive measures can significantly improve the safety and reliability of lithium-ion battery packs, meeting increasingly stringent application requirements. Summary of the Invention

[0005] The main objective of this disclosure is to provide a heat dissipation protection structure for lithium-ion battery packs, so as to effectively solve the problems mentioned by the inventors in the background art above, such as the lack of effective support structure, insufficient heat dissipation effect and poor energy absorption effect of existing battery packs.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A heat dissipation protection structure for a lithium-ion battery pack, comprising:

[0008] The protective frame is a rectangular frame formed by end plates and side plates;

[0009] The battery pack includes multiple battery cells stacked sequentially within the protective frame.

[0010] The end plate and the side plate each include an outer protective layer, a heat-resistant heat dissipation layer and an energy-absorbing buffer layer stacked in sequence; the heat-resistant heat dissipation layer has multiple heat dissipation grooves arranged side by side at intervals, the inner wall of the heat dissipation groove has a pressure relief port communicating with the outside, the pressure relief port is inclined outward, a spherical airbag is installed inside the heat dissipation groove, and part of the spherical airbag extends outside the heat dissipation groove and is embedded in the energy-absorbing buffer layer, and the spherical airbag is filled with heat-absorbing liquid.

[0011] Preferably, the heat-resistant heat dissipation layer is embedded with a buffer protrusion, and the top of the buffer protrusion extends outside the heat-resistant heat dissipation layer and is embedded in the energy-absorbing buffer layer.

[0012] Preferably, the heat-resistant heat dissipation layer is provided with a liquid guiding channel, the inner cavity of the buffer protrusion is connected to the inner cavity of the spherical airbag through the liquid guiding channel, and the heat-absorbing liquid can flow between the buffer protrusion and the spherical airbag through the liquid guiding channel.

[0013] Preferably, the end plate and the side plate are fixed by protective fasteners. The outer surface of the end of the side plate is provided with a hook groove. The protective fastener includes an armor strip and hook blocks disposed at both ends of the armor strip. The hook blocks are engaged in the hook groove.

[0014] Preferably, the outer protective layer includes an aluminum substrate and an aluminum silicon carbide layer disposed on the outer surface of the aluminum substrate. A curved liquid cooling channel is disposed inside the aluminum substrate. One end of the liquid cooling channel is connected to a water inlet nozzle, and the other end of the liquid cooling channel is connected to a water outlet nozzle.

[0015] The thermal conductivity of the silicon carbide layer is 220-240 W / mK; the Vickers hardness of the silicon carbide layer is 200-300 HV.

[0016] Preferably, the heat-resistant heat dissipation layer comprises the following components in the indicated weight ratios: 40 parts aluminum nitride powder, 15 parts cubic boron nitride powder, 5 parts graphene nanosheets, 20 parts polyimide resin, 5 parts silane coupling agent, 10 parts nano-sized silver powder, and 5 parts carbon nanotubes.

[0017] Preferably, the energy-absorbing buffer layer includes a first PU layer, a second PU layer, and a third PU layer arranged sequentially from the outside to the inside. The densities ρ1 of the first PU layer, ρ2 of the second PU layer, and ρ3 of the third PU layer satisfy the relationship: ρ1 > ρ2 > ρ3. Furthermore, the first PU layer, the second PU layer, and the third PU layer are all provided with staggered pore structures, and the porosity Q1 of the first PU layer, Q2 of the second PU layer, and Q3 of the third PU layer satisfy the relationship: Q1 < Q2 < Q3.

[0018] The thicknesses H1 of the first PU layer, H2 of the second PU layer, and H3 of the third PU layer satisfy the following relationship: H1 < H2 < H3.

[0019] Preferably, the density ρ1 of the first PU layer is 200 kg / m³. 3 ~300kg / m 3 The density ρ2 of the second PU layer is 100 kg / m³. 3 ~200kg / m 3 The density ρ3 of the third PU layer is 50 kg / m³. 3 ~100kg / m 3 ;

[0020] The porosity Q1 of the first PU layer is 20% to 30%; the porosity Q2 of the second PU layer is 30% to 50%; and the porosity Q3 of the third PU layer is 50% to 70%.

[0021] The thickness H1 of the first PU layer is 0.1 to 0.5 mm; the thickness H2 of the second PU layer is 0.5 to 1.5 mm; and the thickness H3 of the third PU layer is 1.5 to 3 mm.

[0022] Preferably, the endothermic liquid is composed of phase change material, sodium chloride, TiO2 particles and water; the mass ratio of the phase change material, sodium chloride, TiO2 particles and water is (15-45):(5-15):(10-30):(40-60).

[0023] Preferably, the phase change material is a mixture of gallium, indium bismuth tin alloy and ortho-decanoic acid, wherein the mass ratio of gallium, indium bismuth tin alloy and ortho-decanoic acid is (1-2):(1-2):(2-4).

[0024] Preferably, the phase change material can be dispersed in the solution in particulate form, with a particle size range of 1 μm to 100 μm; the TiO2 particles have a particle size range of 0.1 μm to 10 μm.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention uses a protective frame consisting of a rectangular frame formed by special end plates and side plates, which not only provides a robust support structure for the battery pack, but also effectively prevents external impacts from damaging the battery pack. In addition, it also has a better heat dissipation effect on the battery pack. This structural design significantly increases the overall stability and durability of the battery pack.

[0026] The end plate and side plate of this invention include an outer protective layer, a heat-resistant and heat-dissipating layer, and an energy-absorbing buffer layer stacked sequentially. The heat-resistant and heat-dissipating layer is designed with multiple heat dissipation grooves, which are connected to the outside through pressure relief ports. This improves air convection and ventilation within the protective frame. Combined with the spherical airbags installed within the heat dissipation grooves and their internal heat-absorbing liquid, heat is further absorbed and transferred, thereby improving overall heat dissipation efficiency and preventing the battery pack from being under heat for extended periods, effectively protecting the battery pack. Furthermore, the heat dissipation grooves and pressure relief ports effectively disperse pressure during use, reducing stress generation and improving the protective frame's pressure resistance, thus reducing the risk of battery damage due to temperature increases or external impacts. Additionally, a portion of the spherical surface of the airbag extends outside the heat dissipation grooves and is embedded in the energy-absorbing buffer layer, which not only facilitates further heat diffusion but also enhances the heat exchange efficiency between the heat-resistant and heat-dissipating layer and the energy-absorbing buffer layer.

[0027] The energy-absorbing buffer layer effectively absorbs the energy of external impacts through its highly elastic and compressible material properties. When subjected to drops, collisions, or other physical impacts, the buffer layer deforms, absorbing and dispersing the impact energy and reducing the force directly acting on the battery cells, thus protecting them from damage. Furthermore, during transportation or use, the battery pack may be subjected to various vibrations, which can gradually damage the battery structure and shorten battery life. The energy-absorbing buffer layer has excellent vibration isolation performance, effectively isolating or reducing the impact of these vibrations on the battery cells, improving the stability and reliability of the battery pack. The outer protective layer not only provides excellent thermal conductivity but also has strong wear resistance and impact resistance, ensuring the protective frame's resistance to damage from external impacts or pressures, thus making the battery pack safer and more reliable. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a battery heat dissipation protection structure according to an embodiment of the present invention;

[0029] Figure 2 This is a top view of a heat dissipation protection structure according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of an end plate or side plate in one embodiment of the present invention;

[0031] Figure 4 This is a cross-sectional view of an end plate or side plate in one embodiment of the present invention;

[0032] Figure 5 for Figure 4 A magnified view of part A in the middle;

[0033] Figure 6 This is a cross-sectional view of the energy-absorbing buffer layer in one embodiment of the present invention;

[0034] Figure 7 This is a cross-sectional view of the outer protective layer in one embodiment of the present invention.

[0035] In the diagram: 1. End plate; 11. Energy-absorbing buffer layer; 111. First PU layer; 112. Second PU layer; 113. Third PU layer; 12. Heat-resistant heat dissipation layer; 121. Heat dissipation groove; 122. Pressure relief port; 123. Spherical airbag; 124. Buffer protrusion; 125. Liquid guide channel; 13. Outer protective layer; 131. Aluminum substrate; 1311. Liquid cooling channel; 1312. Water inlet nozzle; 1313. Water outlet nozzle; 132. Aluminum silicon carbide layer; 2. Side plate; 21. Hook groove; 3. Battery pack; 4. Protective fastener; 41. Armored strip; 42. Hook block. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figures 1 to 7 This embodiment provides a heat dissipation protection structure for a lithium-ion battery pack, comprising:

[0038] The protective frame is a rectangular frame formed by end plate 1 and side plate 2;

[0039] Battery pack 3 includes multiple battery cells stacked sequentially within a protective frame;

[0040] The end plate 1 and the side plate 2 each include an outer protective layer 13, a heat-resistant heat dissipation layer 12 and an energy-absorbing buffer layer 11 stacked in sequence. The heat-resistant heat dissipation layer 12 has multiple heat dissipation grooves 121 arranged side by side at intervals. The inner wall of the heat dissipation groove 121 has a pressure relief port 122 communicating with the outside. The pressure relief port 122 is inclined outward. A spherical airbag 123 is installed inside the heat dissipation groove 121. Part of the spherical surface of the spherical airbag 123 extends outside the heat dissipation groove 121 and is embedded in the energy-absorbing buffer layer 11. The spherical airbag 123 is filled with heat-absorbing liquid.

[0041] The layers of the end plate 1 or the side plate 2 can be integrated into a sheet structure using a hot-press bonding process or a spraying process well known in the art.

[0042] The present invention employs a protective frame consisting of a rectangular frame formed by special end plates 1 and side plates 2, which not only provides an effective support and protection structure to ensure the stability of the battery pack 3 in various environments, but also significantly improves heat dissipation efficiency and energy absorption effect through the multi-layer design of end plates 1 and side plates 2, thereby enhancing the thermal management performance and shock resistance of the battery pack 3.

[0043] In one embodiment of this application, the heat-resistant heat dissipation layer 12 is embedded with a buffer protrusion 124, and the top end of the buffer protrusion 124 extends outside the heat-resistant heat dissipation layer 12 and is embedded in the energy-absorbing buffer layer 11. The buffer protrusion 124 can be made of a polymer material with good elasticity, such as EVA or polyurethane. The buffer protrusion 124 further enhances the mechanical strength and buffering capacity of the heat-resistant heat dissipation layer 12, effectively absorbing and dispersing external impact forces.

[0044] In one embodiment of this application, a liquid guiding channel 125 is provided within the heat-resistant heat dissipation layer 12. The inner cavity of the buffer protrusion 124 is connected to the inner cavity of the spherical airbag 123 through the liquid guiding channel 125, and the heat-absorbing liquid can flow between the buffer protrusion 124 and the spherical airbag 123 through the liquid guiding channel 125. The spherical airbag 123 can be made of a material with good thermal conductivity and elasticity, such as thermally conductive silicone, and is manufactured by injection molding, extrusion molding, or blow molding. The liquid guiding channel 125 design enables the flow of heat-absorbing liquid between the buffer protrusion 124 and the spherical airbag 123, enhancing the efficiency and uniformity of heat dissipation.

[0045] In one embodiment of this application, the end plate 1 and the side plate 2 are fixed by protective fasteners 4. A hook groove 21 is formed on the outer surface of the end of the side plate 2. The protective fastener 4 includes an armor strip 41 and hook blocks 42 disposed at both ends of the armor strip 41, the hook blocks 42 being engaged within the hook groove 21. The end plate 1 and the side plate are connected by a convex-concave fit. To further improve the stability of the connection between the end plate 1 and the side plate 2, the protective fasteners 4 are provided, connecting the end plate 1 and the side plate 2 through the armor strip 41 and the hook blocks 42, providing additional mechanical strength and stability, ensuring the reliability and stability of the protective frame under extreme conditions.

[0046] In one embodiment of this application, the outer protective layer 13 includes an aluminum substrate 131 and an aluminum silicon carbide layer 132 disposed on the outer surface of the aluminum substrate 131. A curved liquid cooling channel 1311 is disposed inside the aluminum substrate 131. One end of the liquid cooling channel 1311 is connected to a water inlet nozzle 1312, and the other end of the liquid cooling channel 1311 is connected to a water outlet nozzle 1313. The thermal conductivity of the silicon carbide layer is 220-240 W / mK, preferably 240 W / mK. The Vickers hardness of the silicon carbide layer is 200-300 HV, preferably 300 HV.

[0047] The aluminum substrate 131 typically has a Vickers hardness between 30 and 40 HV. Aluminum's relatively low hardness makes it easy to process and shape, facilitating the fabrication of the liquid cooling channel 1311, but its wear resistance and impact resistance are insufficient. Aluminum silicon carbide, with a Vickers hardness between 200 and 300 HV, is placed on the outer side of the aluminum substrate 131 as an outer protective layer 13 for the end plate 1 or side plate 2, making it more wear-resistant and impact-resistant. Therefore, the outer protective layer 13 is a combination of the aluminum substrate 131 and the aluminum silicon carbide layer 132. The aluminum silicon carbide layer 132 has an extremely high thermal conductivity (220-240 W / mK), allowing heat to be rapidly conducted away from the battery cells through the outer protective layer 13. Furthermore, the curved liquid cooling channel 1311 inside the aluminum substrate 131 further enhances heat dissipation efficiency. The circulating coolant effectively removes heat from the battery pack 3, greatly improving the heat dissipation speed and effect. Furthermore, the aluminum silicon carbide layer 132 of the outer protective layer 13 not only provides excellent thermal conductivity, but also has a Vickers hardness between 200 and 300 HV, ensuring the protective frame's resistance to damage when facing external impacts or pressures. This wear-resistant and impact-resistant property makes the battery pack 3 safer and more reliable in daily use.

[0048] In one embodiment of this application, the heat-dissipating and heat-resistant layer 12 comprises the following components in parts by weight: 40 parts aluminum nitride powder, 15 parts cubic boron nitride powder, 5 parts graphene nanosheets, 20 parts polyimide resin, 5 parts silane coupling agent, 10 parts nanoscale silver powder, and 5 parts carbon nanotubes.

[0049] This material combines aluminum nitride, cubic boron nitride, graphene nanosheets, nanoscale silver powder, and carbon nanotubes to achieve a balance of high thermal conductivity, high-temperature resistance, and mechanical strength. Aluminum nitride and cubic boron nitride, with their high thermal conductivity, enhance heat dissipation efficiency, while graphene nanosheets and carbon nanotubes further improve thermal conductivity. Polyimide resin is used as a high-temperature resistant matrix material, working in conjunction with the high thermal conductivity filler to provide excellent heat dissipation and high-temperature resistance. A silane coupling agent is used to modify the surface of the filler, improving the interfacial adhesion between the filler and the matrix and enhancing the overall performance of the material. Furthermore, the synergistic effect of the components forms a highly efficient thermally conductive network, further improving the material's thermal conductivity and heat dissipation performance.

[0050] The method for preparing the heat-resistant heat dissipation layer 12 is as follows:

[0051] Step 1: Pre-processing

[0052] Materials preparation:

[0053] Weigh aluminum nitride powder, cubic boron nitride powder, graphene nanosheets, nanoscale silver powder, and carbon nanotubes according to the specified proportions and set aside.

[0054] Prepare the polyimide resin and silane coupling agent.

[0055] Surface modification:

[0056] The fillers (aluminum nitride, cubic boron nitride, graphene nanosheets, nanoscale silver powder and carbon nanotubes) were mixed with silane coupling agents in anhydrous ethanol and stirred for 2 hours to perform surface modification.

[0057] The modified filler was dried at 80°C to remove residual ethanol.

[0058] Step 2: Mixing and Dispersing

[0059] Mixed packing:

[0060] Mix the modified fillers using a high-speed mixer or ball mill to ensure uniform dispersion; control the mixing time to more than 2 hours to ensure that all components are fully mixed.

[0061] Add matrix material:

[0062] The polyimide resin was dissolved in N-methylpyrrolidone (NMP) to form a homogeneous solution;

[0063] The mixed filler is gradually added to the polyimide solution, and stirring is continued until a uniform slurry is formed.

[0064] Step 3: Molding and Curing

[0065] The uniformly mixed slurry is evenly coated onto the aluminum substrate 131;

[0066] The coated aluminum substrate 131 was dried at 80°C for 2 hours to allow the NMP solvent to evaporate completely.

[0067] Then, the aluminum substrate 131 is placed in an oven and cured at 300°C for 2 hours to allow the polyimide resin to fully crosslink and cure, thus obtaining the heat-resistant heat dissipation layer 12.

[0068] In one embodiment of this application, the heat-resistant heat dissipation layer 12 may also be made of metal or alloy materials with high temperature resistance and thermal conductivity, such as aluminum, copper and their alloys.

[0069] In one embodiment of this application, the energy-absorbing buffer layer 11 includes a first PU layer 111, a second PU layer 112, and a third PU layer 113 arranged sequentially from the outside to the inside. The layers can be integrated into a sheet structure by means of a thermosetting bonding process or a spraying process well known in the art. The densities ρ1 of the first PU layer 111, ρ2 of the second PU layer 112, and ρ3 of the third PU layer 113 satisfy the relationship: ρ1 > ρ2 > ρ3. The first PU layer 111, the second PU layer 112, and the third PU layer 113 are all provided with staggered pore structures. The porosity Q1 of the first PU layer 111, the porosity Q2 of the second PU layer 112, and the porosity Q3 of the third PU layer 113 satisfy the relationship: Q1 < Q2 < Q3.

[0070] The thicknesses H1 of the first PU layer 111, H2 of the second PU layer 112, and H3 of the third PU layer 113 satisfy the following relationship: H1 < H2 < H3.

[0071] The three-layer PU structure design with varying density, porosity, and thickness effectively absorbs and disperses impact energy, providing excellent buffering and protection performance. Specifically, the high-density, low-porosity, and thinner first PU layer 111 initially receives and disperses external impact energy, reducing the direct transmission of impact force to the interior. The medium-density, high-porosity, and moderately thick second PU layer 112 further absorbs and disperses the remaining impact energy. The low-density, high-porosity, and thicker third PU layer 113 has extremely high energy absorption capacity, ultimately absorbing and dispersing the remaining impact energy, protecting the battery pack 3. This application achieves layer-by-layer absorption and dispersion of impact energy through an innovative combination of porosity, density, and thickness design, significantly improving the buffering and protection performance of the lithium-ion battery pack 3. This gradient parameter design provides comprehensive protection under different mechanical environments, ensuring the safety and reliability of the battery module.

[0072] In one embodiment according to this application, the density ρ1 of the first PU layer 111 is 200 kg / m³. 3 ~300kg / m 3 The preferred value is 250 kg / m 3 The density ρ2 of the second PU layer 112 is 100 kg / m³. 3 ~200kg / m 3 The preferred value is 150 kg / m 3 The density ρ3 of the third PU layer 113 is 50 kg / m³. 3 ~100kg / m 3 The preferred value is 75 kg / m 3 .

[0073] The porosity Q1 of the first PU layer 111 is 20% to 30%, preferably 25%; the porosity Q2 of the second PU layer 112 is 30% to 50%, preferably 40%; and the porosity Q3 of the third PU layer 113 is 50% to 70%, preferably 60%.

[0074] The thickness H1 of the first PU layer 111 is 0.1-0.5 mm, preferably 0.4 mm; the thickness H2 of the second PU layer 112 is 0.5-1.5 mm, preferably 1 mm; and the thickness H3 of the third PU layer 113 is 1.5-3 mm, preferably 2 mm.

[0075] In one embodiment of this application, the endothermic liquid is composed of a phase change material, sodium chloride, TiO2 particles, and water; the mass ratio of the phase change material, sodium chloride, TiO2 particles, and water is (15-45):(5-15):(10-30):(40-60); preferably 30:10:20:40. The endothermic liquid formulation contains a phase change material, which absorbs heat and undergoes a phase change at a specific temperature, effectively reducing the battery temperature. The addition of sodium chloride and TiO2 particles further enhances the heat absorption capacity and stability of the endothermic liquid.

[0076] In one embodiment of this application, the phase change material is a mixture of gallium, indium bismuth tin alloy, and ortho-capric acid, wherein the mass ratio of gallium, indium bismuth tin alloy, and ortho-capric acid is (1-2):(1-2):(2-4); preferably 1:1:3. The phase change material possesses excellent thermal absorption and conductivity properties, and the specific mass ratio ensures the stability and high efficiency of the endothermic liquid.

[0077] In one embodiment of this application, the phase change material can be dispersed in the solution in particulate form, with a particle size ranging from 1 μm to 100 μm; the TiO2 particles have a particle size ranging from 0.1 μm to 10 μm. Controlling the particle size ensures the uniformity of the endothermic liquid dispersion, further improving the efficiency and stability of thermal management.

[0078] In one embodiment of this application, the phase change material comprises sodium sulfate decahydrate, multi-walled carbon nanotubes, sodium carboxymethyl cellulose, and polyvinyl alcohol, wherein the mass percentages of sodium sulfate decahydrate, multi-walled carbon nanotubes, sodium carboxymethyl cellulose, and polyvinyl alcohol are 80-85%:5-10%:5-10%:5-10%, preferably 85%:5%:5%:5%. Sodium sulfate decahydrate, as the main phase change material, has a moderate phase change temperature and a high latent heat of phase change, enabling it to significantly absorb heat and thus reduce the battery pack temperature. Multi-walled carbon nanotubes improve the thermal conductivity of the phase change material, ensuring rapid heat diffusion within the material, making the phase change process more uniform and efficient. Sodium carboxymethyl cellulose, as a stabilizer, prevents crystallization deformation and phase separation during repeated use of the phase change material, improving its mechanical strength and stability. Polyvinyl alcohol, as a dispersant, ensures uniform dispersion of multi-walled carbon nanotubes and other additives in the phase change material, preventing aggregation and sedimentation, and improving the overall performance of the material.

[0079] In one embodiment of this application, the endothermic liquid comprises the following components by weight percentage: 20% paraffin wax, 5% sodium chloride, 10% hexagonal boron nitride nanosheets, 2% polyvinyl alcohol, and the balance being water. Paraffin wax, as a phase change material, can absorb a large amount of heat, improving the overall heat dissipation effect; sodium chloride enhances the overall thermal conductivity and lowers the freezing point of water, preventing the solution from freezing in low-temperature environments; hexagonal boron nitride nanosheets significantly improve the thermal conductivity of the endothermic liquid, ensuring rapid heat dispersion within the solution and preventing localized overheating; polyvinyl alcohol ensures uniform dispersion of the hexagonal boron nitride nanosheets in the solution, preventing aggregation and sedimentation, and improving the overall performance and stability of the solution; water, as the matrix solution, provides good fluidity and thermal conductivity, ensuring uniform dispersion of other components.

[0080] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0081] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A heat dissipation protection structure for a lithium-ion battery pack, characterized in that, include: The protective frame is a rectangular frame formed by end plates and side plates. The battery pack includes multiple battery cells stacked sequentially within the protective frame. The end plate and the side plate each include an outer protective layer, a heat-resistant heat dissipation layer and an energy-absorbing buffer layer stacked in sequence; the heat-resistant heat dissipation layer has multiple heat dissipation grooves arranged side by side at intervals, the inner wall of the heat dissipation groove has a pressure relief port communicating with the outside, the pressure relief port is inclined outward, a spherical airbag is installed inside the heat dissipation groove, and part of the spherical airbag extends outside the heat dissipation groove and is embedded in the energy-absorbing buffer layer, and the spherical airbag is filled with heat-absorbing liquid; The outer protective layer includes an aluminum substrate and an aluminum silicon carbide layer disposed on the outer surface of the aluminum substrate; The energy-absorbing buffer layer includes a first PU layer, a second PU layer, and a third PU layer arranged sequentially from the outside to the inside. The densities ρ1 of the first PU layer, ρ2 of the second PU layer, and ρ3 of the third PU layer satisfy the relationship: ρ1 > ρ2 > ρ3. Furthermore, the first PU layer, the second PU layer, and the third PU layer are all provided with staggered pore structures. The porosity Q1 of the first PU layer, Q2 of the second PU layer, and Q3 of the third PU layer satisfy the relationship: Q1 < Q2 < Q3. The thickness H1 of the first PU layer, H2 of the second PU layer, and H3 of the third PU layer satisfy the relationship: H1 < H2 < H3.

2. The lithium-ion battery pack heat dissipation protection structure according to claim 1, characterized in that: The heat-resistant heat dissipation layer is embedded with a buffer protrusion, and the top of the buffer protrusion extends outside the heat-resistant heat dissipation layer and is embedded in the energy-absorbing buffer layer.

3. The lithium-ion battery pack heat dissipation protection structure according to claim 2, characterized in that: The heat-resistant heat dissipation layer is provided with a liquid guiding channel. The inner cavity of the buffer protrusion is connected to the inner cavity of the spherical airbag through the liquid guiding channel, and the heat-absorbing liquid can flow between the buffer protrusion and the spherical airbag through the liquid guiding channel.

4. The lithium-ion battery pack heat dissipation protection structure according to claim 1, characterized in that: The end plate and the side plate are fixed by protective fasteners. The outer surface of the end of the side plate is provided with a hook groove. The protective fastener includes an armor strip and hook blocks provided at both ends of the armor strip. The hook blocks are engaged in the hook groove.

5. The heat dissipation protection structure for a lithium-ion battery pack according to claim 1, characterized in that: The aluminum substrate has a curved liquid cooling channel inside, one end of which is connected to a water inlet nozzle, and the other end of which is connected to a water outlet nozzle. The thermal conductivity of the aluminum silicon carbide layer is 220-240 W / mK; the Vickers hardness of the aluminum silicon carbide layer is 200-300 HV.

6. The heat dissipation protection structure for a lithium-ion battery pack according to claim 1, characterized in that: The heat-resistant and heat-dissipating layer comprises the following components in the indicated weight ratios: 40 parts aluminum nitride powder, 15 parts cubic boron nitride powder, 5 parts graphene nanosheets, 20 parts polyimide resin, 5 parts silane coupling agent, 10 parts nano-sized silver powder, and 5 parts carbon nanotubes.

7. The lithium-ion battery pack heat dissipation protection structure according to claim 1, characterized in that: The density ρ1 of the first PU layer is 200 kg / m³ to 300 kg / m³; the density ρ2 of the second PU layer is 100 kg / m³ to 200 kg / m³; and the density ρ3 of the third PU layer is 50 kg / m³ to 100 kg / m³. The porosity Q1 of the first PU layer is 20%~30%; the porosity Q2 of the second PU layer is 30%~50%; and the porosity Q3 of the third PU layer is 50%~70%. The thickness H1 of the first PU layer is 0.1~0.5mm; the thickness H2 of the second PU layer is 0.5~1.5mm; and the thickness H3 of the third PU layer is 1.5~3mm.

8. The heat dissipation protection structure for a lithium-ion battery pack according to claim 1, characterized in that: The endothermic liquid is composed of phase change material, sodium chloride, and Composed of particles and water; the phase change material, sodium chloride, The mass ratio of particles to water is (15~45):(5~15):(10~30):(40~60).

9. A heat dissipation protection structure for a lithium-ion battery pack according to claim 8, characterized in that: The phase change material is a mixture of gallium, indium bismuth tin alloy and ortho-capric acid, and the mass ratio of gallium, indium bismuth tin alloy and ortho-capric acid is (1~2):(1~2):(2~4).

Images