Battery thermal insulation pad and battery pack

Abstract

The application discloses a battery heat insulation pad and a battery pack, and belongs to the technical field of batteries. The battery heat insulation pad comprises a heat insulation main body, the heat insulation main body comprises fiber filaments, aerogel and a light shielding agent, the light shielding agent comprises a plurality of particles, the average particle size of the particles of the light shielding agent is A mu m, the light shielding agent is used for absorbing and scattering infrared radiation, the fiber filaments serve as the framework of the heat insulation matrix, and the aerogel is dispersed between the fiber filaments; the mass content of the fiber filaments and the light shielding agent in the battery heat insulation pad is x%, the diameter of the fiber filaments is D mu m, and the range of x / (A*D) is 0.025-16.276. The x / (A*D) is controlled in the range of 0.025-16.276, so that the battery heat insulation pad has good barrier effects on thermal radiation, thermal conduction and thermal convection above 600 DEG C, and the mechanical strength and service life of the battery heat insulation pad are ensured.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery heat insulation pad and a battery pack. Background Technology

[0002] In the prior art, in order to reduce the heat transfer from the thermally runaway battery to adjacent batteries during battery thermal runaway, battery thermal insulation pads are placed between adjacent batteries. However, existing battery thermal insulation pads have poor heat insulation effect at the high temperature of thermal runaway, which causes a large amount of heat from the thermally runaway battery to be transferred to adjacent batteries, causing the entire battery pack to thermally runaway and seriously affecting the safety of the battery pack.

[0003] Therefore, how to improve the heat insulation effect and reduce the risk of thermal runaway of the battery pack is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a battery heat insulation pad to improve the heat insulation effect and reduce the risk of thermal runaway of the battery pack.

[0005] Another object of this application is to provide a battery pack having the above-mentioned battery heat insulation pad.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] The first aspect of this application provides a battery heat insulation pad, including a heat insulation body, the heat insulation body comprising fibers, aerogel and a light-blocking agent, wherein at least the fibers and the aerogel are mixed to form a heat insulation matrix, the light-blocking agent comprising a plurality of particles, the average particle size of the light-blocking agent particles being A μm, the light-blocking agent being used to absorb and scatter infrared radiation, the fibers serving as the skeleton of the heat insulation matrix, and the aerogel being dispersed between the fibers;

[0008] The mass content of the fiber and the light-blocking agent in the heat insulation body is x%, the diameter of the fiber is D μm, and the range of x / (A×D) is 0.025~16.276.

[0009] The battery heat insulation pad disclosed in the above technical solution effectively absorbs and scatters infrared radiation generated by battery thermal radiation by adding a light-blocking agent to the heat insulation body containing fibers and aerogel. The aerogel can better block heat generated by heat conduction and heat convection, and the fibers can provide skeletal support for the aerogel, improving the overall structural strength of the battery heat insulation pad. By adjusting the diameter Dμm of the fibers in the battery heat insulation pad, the mass content x of the light-blocking agent and fibers, and the particle size Aμm of the light-blocking agent, x / (A×D) is kept within the range of 0.025~16.276 to ensure that the battery heat insulation pad has a good blocking effect on heat radiation, heat conduction and heat convection above 600℃, while ensuring the mechanical strength and service life of the battery heat insulation pad.

[0010] The x / (A×D) ratio in this application is selected within the range of 0.025 to 16.276. This avoids the problem that if the above relationship is too small, the mass content of the light-blocking agent and fiber filaments will be too low, the average particle size of the light-blocking agent will be too large, and the diameter Dμm of the fiber filaments will be too large. This would result in poor heat radiation blocking ability of the battery heat insulation pad, and after battery thermal runaway, the temperature of adjacent batteries would rise too quickly, affecting the overall thermal safety of the battery pack. Conversely, if the above relationship is too large, the mass content of the light-blocking agent and fiber filaments will be too high, the average particle size of the light-blocking agent will be too small, and the diameter Dμm of the fiber filaments will be too small. The smaller the particle size of the light-blocking agent, the easier it is to agglomerate. The smaller the diameter Dμm of the fiber filaments, the easier it is for the fiber filaments to break. This avoids the problem that if the above relationship is too large, the mechanical properties of the battery heat insulation pad will decrease, affecting the service life of the battery heat insulation pad.

[0011] A second aspect of this application provides a battery pack including a battery heat insulation pad as described in any of the preceding claims and at least two batteries, the battery heat insulation pad being located between the first surfaces of two adjacent batteries.

[0012] The battery pack disclosed in the above technical solution has all the technical effects of the battery heat insulation pad, and will not be repeated here. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the battery heat insulation pad disclosed in the embodiments of this application;

[0015] Figure 2Microscopic images of the aerogel and light-blocking agent disclosed in the embodiments of this application;

[0016] Figure 3 Microscopic images of the aerogel and fibers disclosed in the embodiments of this application;

[0017] Figure 4 This is a cross-sectional view of the heat insulation body disclosed in the embodiments of this application;

[0018] Figure 5 This is a schematic diagram of the folding of the insulating encapsulation layer disclosed in the embodiments of this application;

[0019] Figure 6 This is a schematic diagram of the battery pack structure disclosed in an embodiment of this application;

[0020] Figure 7 This is a cross-sectional view of the battery disclosed in an embodiment of this application;

[0021] Figure 8 This is a schematic diagram of the battery pack structure disclosed in an embodiment of this application.

[0022] The meanings of the various reference numerals in the figure are as follows:

[0023] 100-Battery heat insulation pad; 110-Heat insulation body; 111-Opacifier; 112-Aerogel; 113-Fiber filament; 1110-Second heat insulation layer; 1120-First heat insulation layer; 120-Buffer strip; 130-Insulating encapsulation layer; 131-Overlapping area;

[0024] 200 - Battery; 210 - Casing; 220 - Terminal; 230 - Cell; 240 - Pressure relief valve;

[0025] 300-Battery housing. Detailed Implementation

[0026] This application discloses a battery heat insulation pad to improve the heat insulation effect and reduce the risk of thermal runaway of the battery pack.

[0027] This application also discloses a battery pack having the above-described battery heat insulation pad.

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Battery thermal runaway is a serious battery failure mode, characterized by a chain of exothermic reactions triggered by specific factors inside the battery, causing a rapid rise in temperature that cannot be effectively dissipated, and may eventually develop into an irreversible catastrophic process such as fire or explosion.

[0030] Common causes of thermal runaway include the following categories: First, mechanical abuse, such as collisions, squeezing, or punctures, which damage the internal structure of the battery and cause large-scale internal short circuits; second, electrical abuse, including overcharging (which damages the structure of the positive electrode material, oxidizes and decomposes the electrolyte, and generates a large amount of heat and gas), over-discharging (which may cause the negative electrode current collector to dissolve and cause an internal short circuit when recharging), and excessive current charging and discharging (which generates excessive Joule heat and insufficient heat dissipation); in addition, internal defects of the battery itself may also gradually lead to thermal runaway during long-term use.

[0031] To address the risk of severe pressure surges during thermal runaway, battery casings are typically equipped with safety devices such as pressure relief valves. When abnormal gas generation inside the battery causes the pressure to rise to a set threshold, the pressure relief valve will automatically open under pressure to release the high-pressure gas in a timely manner, thereby preventing the battery casing from rupturing or exploding due to pressure accumulation and significantly improving safety redundancy.

[0032] At the battery module or battery pack level, to prevent a chain reaction caused by thermal runaway of a single battery, battery thermal pads are typically installed between the batteries. These pads act as a physical barrier when a battery experiences thermal runaway and releases high-temperature substances, effectively delaying or blocking heat transfer to adjacent batteries, thus inhibiting heat spread and providing a critical time window for system safety response. Furthermore, the elasticity of the battery thermal pads can buffer the expansion and contraction of the battery volume during cyclic use, maintaining the stability of the module structure. In short, battery thermal pads are placed between adjacent batteries to prevent heat conduction between them, preventing the transfer of thermal runaway from one battery to adjacent batteries, thereby inhibiting heat spread within the battery pack.

[0033] The applicant's research revealed that existing battery thermal insulation pads have a weak effect in blocking thermal radiation. Furthermore, when a battery experiences thermal runaway, the runaway temperature is quite high, reaching over 600℃. At this temperature, heat transfer between adjacent batteries is primarily through thermal radiation, and the formula for thermal radiation heat transfer is q = ε × σ × (T1) / (T1) 4 - T2 4 ), where ε is the surface emissivity (ε≥0.85 when the battery insulation pad material is aerogel, and approximately 0.9 when the battery insulation pad material is ceramic or glass fiber), and σ is the Stefan-Boltzmann constant (5.67×10). -8 W / (m 2 ·K 4T1 is the surface temperature of the object (i.e., the thermal runaway temperature), and T2 is the absolute temperature of the environment. It can be seen that the higher the thermal runaway temperature, the greater the thermal radiation heat transfer; the larger the battery capacity, the greater the thermal radiation heat transfer; and the greater the surface emissivity of the material, the greater the thermal radiation heat transfer.

[0034] Due to T1 4 - T2 4 The temperature variation is exponential, causing heat to increase exponentially at high temperatures. Thermal radiation mainly relies on visible light and infrared rays with longer wavelengths. Since electromagnetic waves do not require any medium to propagate, the higher the temperature, the greater the radiant heat. The heat radiated by visible light is much greater than the heat absorbed by the aerogel of the battery insulation pad. The battery insulation pad generally also contains fibers with high thermal conductivity. Under the action of radiant heat, the fibers can quickly transfer heat to adjacent batteries, which further exacerbates thermal runaway, causes heat to spread to adjacent batteries, and the entire battery pack quickly catches fire and explodes.

[0035] Based on this, this application discloses a battery heat insulation pad to improve the heat insulation effect and reduce the risk of thermal runaway of the battery pack.

[0036] like Figures 1-3 As shown, the battery heat insulation pad 100 disclosed in this application includes a heat insulation body 110, which includes fiber filaments 113, aerogel 112, and a light-blocking agent 111. The heat insulation matrix is ​​formed by mixing at least the fiber filaments 113 and the aerogel 112. The light-blocking agent 111 is a particulate material with an average particle size of μm. The light-blocking agent 111 is used to absorb and scatter infrared radiation, i.e., reduce the thermal radiation from a high-temperature object to a low-temperature object. The fiber filaments 113 serve as the skeleton of the heat insulation matrix, and the aerogel 112 is dispersed between the fiber filaments 113, improving the mechanical strength of the battery heat insulation pad 100. The fiber filaments 113 can provide adhesion and support for the aerogel 112 particles, preventing the aerogel 112 particles from collapsing. Numerous and uniform pores are formed between the aerogel 112 particles, improving the heat insulation capability of the aerogel 112.

[0037] The mass content of fiber filament 113 and light-blocking agent 111 in the heat insulation body 110 is x%, the diameter of fiber filament 113 is D μm, and the range of x / (A×D) is 0.025~16.276.

[0038] For example, x / (A×D) can be 0.025, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16.276, etc. This embodiment does not limit the specific value of x / (A×D), and those skilled in the art can select it within the range of 0.025 to 16.276 according to their needs.

[0039] The battery heat insulation pad 100 disclosed in this application effectively absorbs infrared radiation generated by battery thermal radiation by adding a light-blocking agent 111 to the heat insulation body 110 containing fiber filaments 113 and aerogel 112. The aerogel 112 can better block heat generated by heat conduction and heat convection, and the fiber filaments 113 can provide skeletal support for the aerogel 112, thereby improving the overall structural strength of the battery heat insulation pad 100. By adjusting the diameter D μm of the fiber filaments 113 in the heat insulation body 110, and the mass content x% of the light-blocking agent 111 and fiber filaments 113, while adjusting the average particle size A μm of the light-blocking agent 111, x / (A×D) is made to be in the range of 0.025~16.276, so as to ensure that the battery heat insulation pad 100 has a good blocking effect on heat radiation, heat conduction and heat convection above 600°C, while ensuring the mechanical strength and service life of the battery heat insulation pad 100.

[0040] In this embodiment, x / (A×D) is selected within the range of 0.025 to 16.276. This avoids the situation where the above relationship is too small, resulting in insufficient mass content of the light-blocking agent 111 and fiber filament 113 (a low overall mass content of the light-blocking agent 111 and fiber filament 113 indicates that both the mass content of the light-blocking agent 111 and the mass content of the fiber filament 113 are low). This would lead to an excessively large average particle size A of the light-blocking agent 111 and an excessively large diameter Dμm of the fiber filament 113, resulting in poor thermal radiation blocking ability of the battery heat insulation pad 100. After battery thermal runaway, adjacent batteries... Rapid temperature rise can affect the overall thermal safety of the battery pack. This also avoids situations where the above-mentioned relationship is too large, resulting in excessive mass content of the light-blocking agent 111 and fiber filament 113, excessively small average particle size of the light-blocking agent 111, and excessively small diameter Dμm of the fiber filament 113. Smaller particle size of the light-blocking agent 111 makes it easier to agglomerate, and smaller diameter Dμm of the fiber filament 113 makes it easier to break. Therefore, this avoids the problem of decreased mechanical properties of the battery heat insulation pad 100 due to excessively large relationships, thus affecting its service life.

[0041] Furthermore, the range of x / (A×D) is 0.040 to 4.375. For example, x / (A×D) can be 0.040, 0.52, 1.2, 1.7, 2.2, 2.5, 2.8, 3.2, 3.5, 3.8, 4.2, 4.375, etc. This embodiment does not limit the specific value of x / (A×D), and those skilled in the art can select it within the range of 0.040 to 4.375 according to their needs.

[0042] In one specific embodiment of this application, the thickness of the heat insulation body 110 ranges from 0.5mm to 10mm. For example, the thickness of the heat insulation body 110 can be 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. This embodiment does not limit the specific value; those skilled in the art can select a value within the range of 0.5mm to 10mm according to their needs.

[0043] In this embodiment, the thickness of the heat insulation body 110 is selected within the range of 0.5mm to 10mm. This can avoid the problem of poor mechanical properties of the battery heat insulation pad caused by excessive thickness of the heat insulation body 110, and also avoid the problem of poor heat insulation effect of the battery heat insulation pad caused by insufficient thickness of the heat insulation body 110.

[0044] Furthermore, the thickness of the heat insulation body 110 can be selected within the range of 2mm to 6mm. For example, the thickness of the heat insulation body 110 can be 2mm, 2.6mm, 3.1mm, 3.6mm, 4.1mm, 4.6mm, 5.1mm, 5.6mm, 6mm, etc. This embodiment does not limit the specific value; those skilled in the art can select within the range of 2mm to 6mm according to their needs.

[0045] In one specific embodiment of this application, the diameter Dμm of the fiber filament 113 is 3μm to 30μm. Exemplarily, the diameter of the fiber filament 113 can be 3μm, 5μm, 6μm, 10μm, 12μm, 15μm, 18μm, 20μm, 23μm, 25μm, 28μm, 30μm, etc. This embodiment does not limit the specific value of the diameter of the fiber filament 113; those skilled in the art can select a value within the range of 3μm to 30μm according to their needs.

[0046] In this embodiment, selecting the diameter Dμm of the fiber filament 113 within the range of 3μm to 30μm avoids the problem of insufficient structural strength of the battery heat insulation pad 100 due to an excessively small diameter Dμm; it also avoids the problem of insufficient heat insulation effect of the battery heat insulation pad 100 due to an excessively large diameter Dμm, resulting in good thermal conductivity (strong thermal conductivity but weak heat insulation ability of the fiber filament 113). In this embodiment, selecting the diameter Dμm of the fiber filament 113 within the range of 3μm to 30μm ensures both the mechanical strength and the heat insulation effect of the battery heat insulation pad 100.

[0047] Furthermore, the diameter Dμm of the fiber filament 113 is 5μm to 25μm. For example, the diameter of the fiber filament 113 can be 5μm, 7μm, 11μm, 13μm, 16μm, 19μm, 21μm, 24μm, 25μm, etc. This embodiment does not limit the specific value of the diameter of the fiber filament 113; those skilled in the art can select it within the range of 5μm to 25μm according to their needs.

[0048] The length of the fiber filament 113 can be from 5mm to 20mm. For example, the length of the fiber filament 113 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, etc. This embodiment does not limit the specific value of the length of the fiber filament 113, and those skilled in the art can select it within the range of 5mm to 20mm according to their needs.

[0049] The mass content of fiber filament 113 in the heat insulation body 110 is 0.5% to 10%. For example, the mass content of fiber filament 113 in the heat insulation body 110 can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 8%, 9%, 10%, etc. This embodiment does not limit the specific value of the mass content of fiber filament 113 in the heat insulation body 110; those skilled in the art can select a value within the range of 0.5% to 10% according to their needs.

[0050] In this embodiment, the mass content of fiber filament 113 in the heat insulation body 110 is selected within the range of 0.5% to 10%. This can avoid the problem of insufficient structural strength of the battery heat insulation pad 100 due to too small a mass content of fiber filament 113; it can also avoid the problem of insufficient heat insulation effect of the battery heat insulation pad 100 due to too large a mass content of fiber filament 113, which results in good thermal conductivity (strong thermal conductivity of fiber filament 113, weak heat insulation ability).

[0051] In a specific embodiment of this application, the fiber filament 113 comprises one or more of glass fiber, ceramic fiber, and basalt fiber. The ceramic fiber may be selected from at least one of aluminosilicate fiber (Al2O3-SiO2), mullite fiber (3Al2O3·2SiO2), alumina fiber (Al2O3), silicon nitride fiber, etc. (Si3N4).

[0052] The fiber filament 113 may consist of only the single material described above, or it may consist of a mixture of two or more materials. This embodiment does not limit the specific material of the fiber filament 113, and is not limited to the specific materials disclosed above. Those skilled in the art can select the material of the fiber filament 113 based on their needs.

[0053] In one specific embodiment of this application, the length of the fiber filament 113 is greater than the average particle size Å of the light-blocking agent 111. When the thermal insulation matrix comprises fiber filament 113 and aerogel 112, in this embodiment, because the fiber filament 113 has a larger length, more aerogel 112 particles can be attached to the fiber filament 113, thus improving the barrier capability against heat conduction. When the thermal insulation matrix comprises fiber filament 113, aerogel 112, and light-blocking agent 111, in this embodiment, because the fiber filament 113 has a larger length, more aerogel 112 particles and light-blocking agent 111 particles can be attached to the fiber filament 113, thus improving the barrier capability against heat radiation and heat conduction.

[0054] The mass content of the light-blocking agent 111 in the heat insulation body 110 can range from 10% to 40%. For example, the mass content of the light-blocking agent 111 in the heat insulation body 110 can be 10%, 13%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 33%, 35%, 38%, 40%, etc. This embodiment does not limit the specific value of the mass content of the light-blocking agent 111; those skilled in the art can select it within the range of 10% to 40% according to their needs.

[0055] In this embodiment, the mass content of the light-blocking agent 111 in the heat insulation body 110 is selected within the range of 10% to 40%. This can avoid the problem that the mechanical properties of the battery heat insulation pad 300 will deteriorate due to the excessive mass content of the light-blocking agent 111, and can also avoid the problem that the heat insulation effect of the battery heat insulation pad 300 will deteriorate due to the insufficient mass content of the light-blocking agent 111.

[0056] In one specific embodiment of this application, the specific surface area of ​​the heat insulation body 110 is 50m². 2 / g~1000m 2 / g. For example, the specific surface area of ​​the insulation body 110 can be 50m². 2 / g, 100m 2 / g、200m 2 / g、300m 2 / g、400m 2 / g、500m 2 / g、600m 2 / g、700m 2 / g、800m 2 / g、900m 2 / g, 1000m 2 / g, etc. This embodiment does not limit the specific value of the specific surface area of ​​the heat insulation body 110; those skilled in the art can adjust it according to requirements, such as 50m². 2 / g~1000m 2 Choose within the range of / g.

[0057] This design avoids the problem of low mechanical strength and short service life of battery heat insulation pad 100 due to excessively large specific surface area of ​​heat insulation body 110; it also avoids the problem of poor heat insulation effect due to excessively small specific surface area of ​​heat insulation body 110.

[0058] In a specific embodiment of this application, the mass content (x%) of fiber filament 113 and light-blocking agent 111 in the heat insulation body 110 is 10.5% to 50%. Exemplarily, x% can be 10.5%, 13%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 33%, 35%, 38%, 40%, 45%, 48%, 50%, etc. This embodiment does not limit the specific value of x% mentioned above; those skilled in the art can select from the range of 10.5% to 50% according to their needs.

[0059] In this embodiment, the mass content x% of fiber filament 113 and light-blocking agent 111 in the heat insulation body 110 is selected within the range of 10.5% to 50%. This can prevent the problem of poor mechanical strength of battery heat insulation pad 100 caused by excessive mass content x% of fiber filament 113 and light-blocking agent 111 in the heat insulation body 110; it can also prevent the problem of poor heat radiation blocking effect caused by excessive mass content x% of fiber filament 113 and light-blocking agent 111 in the heat insulation body 110.

[0060] Furthermore, the mass content (x%) of fiber filament 113 and light-blocking agent 111 in the heat insulation body 110 can be from 12% to 48%. For example, x% can be 12%, 14%, 16%, 19%, 21%, 23%, 26%, 29%, 31%, 34%, 37%, 42%, 46%, 48%, etc. This embodiment does not limit the specific value of x% mentioned above; those skilled in the art can select from the range of 12% to 48% according to their needs.

[0061] In one specific embodiment of this application, the mass content of aerogel 112 in the heat insulation body 110 is 50% to 80%. For example, the mass content of aerogel 112 in the heat insulation body 110 can be 50%, 53%, 55%, 58%, 60%, 62%, 65%, 67%, 70%, 73%, 75%, 78%, 80%, etc. This embodiment does not limit the specific value of the mass content of aerogel 112; those skilled in the art can select a value within the range of 50% to 80% according to their needs.

[0062] In this embodiment, the mass content of aerogel 112 in the heat insulation body 110 is selected within the range of 50% to 80%. This avoids the problem that the heat insulation effect of the battery heat insulation pad 100 will be poor due to the low content of light-blocking agent 111 caused by the excessive mass content of aerogel 112; it also avoids the problem that the mechanical properties of the battery heat insulation pad 100 will be poor due to the insufficient mass content of aerogel 112.

[0063] The aerogel 112 comprises one or more of the following: fumed silica aerogel, fumed silica, alumina aerogel, and zirconia aerogel. Aerogel 112 may consist of only one of the above-mentioned materials, or it may consist of a mixture of two or more materials. This embodiment does not limit the specific materials of aerogel 112, and is not limited to the specific materials disclosed above. Those skilled in the art can select the materials of aerogel 112 based on their needs.

[0064] Aerogel 112 may comprise multiple particles, with pores formed between the particles. The larger the pore size, the worse the blocking effect of the battery heat insulation pad 100 on heat conduction and heat convection. Conversely, the smaller the pore size, the better the blocking effect on heat conduction and heat convection. However, when the battery 200 is in normal use, its temperature is transferred to the battery heat insulation pad 100 during charging and discharging. Because the battery heat insulation pad 100 has a superior blocking effect on heat conduction and heat convection, it traps this temperature, causing the battery heat insulation pad 100 to remain at a high temperature for a long time. This can lead to the aerogel 112 breaking down and affecting the structural strength of the battery heat insulation pad 100.

[0065] Therefore, in this embodiment, the pore size range of the pores between the particles of aerogel 112 is 2nm to 70nm. For example, the pore size range can be 2nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, etc. This embodiment does not limit the specific value of the pore size; those skilled in the art can select values ​​within the range of 2nm to 70nm according to their needs.

[0066] This design avoids the problem of poor heat conduction and convection blocking effect caused by excessively large pore sizes between aerogel particles; it also avoids the problem of aerogel 112 breaking down and affecting the structural strength of battery heat insulation pad 100 due to excessively small pore sizes between aerogel particles causing the battery heat insulation pad 100 to be in a high-temperature state for a long time.

[0067] The Dv50 of the aerogel 112 particles can range from 7 nm to 20 μm. For example, the Dv50 of the aerogel 112 particles can be 7 nm, 100 nm, 500 nm, 1 μm, 3 μm, 5 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, etc. This embodiment does not limit the specific value of the Dv50 of the aerogel 112 particles; those skilled in the art can select a value within the 7 nm to 20 μm range according to their needs.

[0068] In one specific embodiment of this application, the light-shielding agent 111 includes one or more of the following: carbon black, silicon carbide, titanium dioxide, zirconium silicate, and zirconium oxide. The light-shielding agent 111 may consist of only one of the above-mentioned materials, or it may be a mixture of two or more materials. This embodiment does not limit the specific material of the light-shielding agent 111, and is not limited to the specific materials disclosed above. Any material capable of absorbing and dissipating infrared radiation is acceptable. Those skilled in the art can select the material of the light-shielding agent 111 based on their needs.

[0069] Given a fixed mass content of the light-shielding agent 111, the smaller the particle size of the light-shielding agent 111, the more infrared radiation it absorbs and dissipates, the more heat it absorbs from thermal radiation, and the better its heat insulation effect. However, if the average particle size Aμm of the light-shielding agent 111 is too small, the particles are prone to agglomeration, resulting in uneven distribution of the light-shielding agent 111 in the heat insulation plate, leading to poor mechanical properties of the battery heat insulation pad 100. If the average particle size Aμm of the light-shielding agent 111 is too large, the blocking effect against thermal radiation is poor.

[0070] Therefore, in a specific embodiment of this application, the average particle size Aμm of the opaque agent 111 ranges from 1μm to 15μm. For example, the average particle size Aμm of the opaque agent 111 can be 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, etc. This embodiment does not limit the specific value of the average particle size of the opaque agent 111; those skilled in the art can select a value within the range of 1μm to 15μm according to their needs.

[0071] In this embodiment, the average particle size Aμm of the light-shielding agent 111 is selected within the range of 1μm to 15μm. This avoids the problem that if the average particle size Aμm of the light-shielding agent 111 is too small, the particles of the light-shielding agent 111 will easily agglomerate, resulting in uneven distribution of the light-shielding agent 111 in the heat insulation plate and poor mechanical properties of the battery heat insulation pad 100. It also avoids the problem that if the average particle size Aμm of the light-shielding agent 111 is too large, the blocking effect on heat radiation will be poor.

[0072] Furthermore, the average particle size Aμm of the opaque agent 111 can range from 2μm to 14μm. For example, the average particle size Aμm of the opaque agent 111 can be 2μm, 2.5μm, 3.5μm, 4.5μm, 5.5μm, 6.5μm, 7.5μm, 8.5μm, 9.5μm, 10.5μm, 11.5μm, 12.5μm, 13.5μm, 14μm, etc. This embodiment does not limit the specific value of the average particle size of the opaque agent 111; those skilled in the art can select a value within the range of 2μm to 14μm according to their needs.

[0073] In one specific embodiment of this application, a light-blocking agent 111, fiber filaments 113, and aerogel 112 are mixed to form a layered thermal insulation matrix. In this embodiment, the light-blocking agent 111 is mixed with fiber filaments 113 and aerogel 112 in the same layer, so that the thermal insulation matrix can simultaneously block heat radiation, heat conduction, and heat convection, resulting in a better thermal insulation effect.

[0074] Furthermore, the range of x / (A×D) is 0.025 to 16.05. For example, x / (A×D) can be 0.025, 0.4, 0.8, 1.45, 2.1, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5, 10.5, 11.5, 12.5, 13.5, 14.5, 15.5, 16.05, etc. This embodiment does not limit the specific value of x / (A×D), and those skilled in the art can select it within the range of 0.025 to 16.05 according to their needs.

[0075] In this embodiment, since the light-blocking agent 111, fiber filament 113 and aerogel 112 are mixed together, they can simultaneously block heat convection, heat conduction and heat radiation in the same layer, resulting in a better heat insulation effect. Therefore, the upper limit of x / (A×D) can be reduced to avoid the problem of decreased mechanical properties of the battery heat insulation pad 100, ensure the structural strength of the battery heat insulation pad 100 and improve its service life.

[0076] Furthermore, when the heat-insulating matrix is ​​formed by mixing the light-blocking agent 111, fiber filaments 113, and aerogel 112, the mass content (x%) of fiber filaments 113 and light-blocking agent 111 in the battery heat-insulating pad 100 is 10.5% to 48%. This reduces the upper limit of x, preventing a decrease in the mechanical properties of the battery heat-insulating pad 100, ensuring its structural strength, and improving its service life. For example, x% can be 10.5%, 13.5%, 15.5%, 18.5%, 20.5%, 22.5%, 25.5%, 27.5%, 30.5%, 33.5%, 35.5%, 38.5%, 40.5%, 45.5%, 48%, etc. This embodiment does not limit the specific value of x% mentioned above; those skilled in the art can select values ​​within the range of 10.5% to 48% according to their needs.

[0077] like Figure 4 As shown in a specific embodiment of this application, the heat insulation body 110 includes a first heat insulation layer 1120 and a second heat insulation layer 1110 stacked together. The first heat insulation layer 1120 includes a heat insulation matrix formed by mixing at least fiber filaments 113 and aerogel 112, and the second heat insulation layer 1110 includes a light-shielding agent layer.

[0078] In this embodiment, the fiber 113 and aerogel 112 are mixed in the same layer, while the light-blocking agent 111 is distributed in a different layer from the fiber 113 and aerogel 112. In other words, the first heat insulation layer 1120 does not contain the light-blocking agent 111, and the second heat insulation layer 1110 does not contain the fiber 113 and aerogel 112.

[0079] In this embodiment, the light-blocking agent 111, aerogel 112, and fiber filament 113 are disposed in different heat insulation layers. This makes it easier to process the first heat insulation layer 1120 and the second heat insulation layer 1110 when processing the heat insulation body 110, since the first heat insulation layer 1120 does not need to be mixed with other materials (e.g., the light-blocking agent 111 does not need to be mixed into the first heat insulation layer 1120, and the fiber filament 113 and aerogel 112 do not need to be mixed into the second heat insulation layer 1110). In other words, the heat insulation body 110 containing the first heat insulation layer 1120 and the second heat insulation layer 1110 is easier to process, and since it is not necessary to control the mass ratio between components, it is easier to ensure the processing quality.

[0080] It should be noted that the first heat insulation layer 1120 primarily blocks heat conduction, while the second heat insulation layer 1110 primarily absorbs heat radiation. Of course, the first heat insulation layer 1120 may also contain a light-blocking agent 111, as long as it is primarily composed of fiber filaments 113 and aerogel 112. Similarly, the second heat insulation layer 1110 may also contain both fiber filaments 113 and aerogel 112, as long as it is primarily composed of a light-blocking agent 111.

[0081] The heat insulation body 110 can form a two- or three-layer structure. Taking a three-layer structure as an example, the first heat insulation layer 1120 can be inside and the two second heat insulation layers 1110 can be outside, or the two first heat insulation layers 1120 can be outside and the second heat insulation layers 1110 can be inside. Preferably, the first heat insulation layer 1120 is inside and the second heat insulation layer 1110 is outside, which can absorb visible light and infrared light in a timely manner and reduce the transfer of radiative heat between batteries.

[0082] The thickness of the first heat insulation layer 1120 is 0.3mm to 7mm. For example, the thickness of the first heat insulation layer 1120 can be 0.3mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, etc. This embodiment does not limit the specific value of the thickness of the first heat insulation layer 1120. Those skilled in the art can select it within the range of 0.3mm to 7mm according to their needs.

[0083] The first heat insulation layer 1120 includes fiber filaments 113 and aerogel 112. In this embodiment, the thickness of the first heat insulation layer 1120 is selected in the range of 0.3mm to 7mm, which can ensure that the battery heat insulation pad 100 has better structural strength and avoid the collapse of the battery heat insulation pad 100 structure, thus affecting the service life of the battery heat insulation pad 100.

[0084] The thickness of the second heat insulation layer 1110 is 0.02mm to 1mm. For example, the thickness of the second heat insulation layer 1110 can be 0.02mm, 0.05mm, 0.07mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc. This embodiment does not limit the specific value of the thickness of the second heat insulation layer 1110. Those skilled in the art can select it within the range of 0.02mm to 1mm according to their needs.

[0085] The second heat insulation layer 1110 includes a light-blocking agent 111. In this embodiment, the thickness of the second heat insulation layer 1110 is selected within the range of 0.02mm to 1mm. This avoids the risk of structural performance degradation and structural collapse of the battery heat insulation pad 100 due to excessive thickness of the second heat insulation layer 1110; it also avoids the problem of poor heat insulation effect due to insufficient thickness of the second heat insulation layer 1110.

[0086] like Figure 5As shown in a specific embodiment of this application, the battery heat insulation pad further includes an insulating encapsulation layer 130, and the heat insulation body 110 is encapsulated within the insulating encapsulation layer 130. The material of the insulating encapsulation layer 130 may include at least one of polyethylene terephthalate (PET), polyimide (PI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polycarbonate (PC), etc. The insulating encapsulation layer 130 may be in the form of a thin film, and the insulating encapsulation layer 130 may be adhered to the heat insulation body 110 by hot melting or adhesive layer.

[0087] Since both aerogel 112 and light-blocking agent 111 are granular structures, the heat insulation body 110 composed of their mixture is a bulk structure. In this embodiment, the heat insulation body 110 is encapsulated in an insulating encapsulation layer 130. The insulating encapsulation layer 130 can wrap and encapsulate the bulk heat insulation body 110, preventing the heat insulation body 110 from collapsing and improving the structural strength of the battery heat insulation pad 100.

[0088] Furthermore, the thickness of the insulating encapsulation layer 130 is 50μm to 200μm to ensure encapsulation effect and improve mechanical strength. For example, the thickness of the insulating encapsulation layer 130 can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, etc. This embodiment does not limit the specific value of the thickness of the insulating encapsulation layer 130; those skilled in the art can select a value within the range of 50μm to 200μm according to their needs.

[0089] In one specific embodiment of this application, the insulating encapsulation layer 130 includes at least two terminal ends, which refer to the ends of the insulating encapsulation layer 130. For example, during encapsulation, the heat insulation body 110 can be placed on the upper side of the insulating encapsulation layer 130 and located in the middle region of the insulating encapsulation layer 130, and then the four ends (i.e., the four terminal ends) of the insulating encapsulation layer 130 are folded towards the upper side of the heat insulation body 110. Figure 5 The dotted line in the diagram can be understood as the end of the inwardly folded-in tail, so that the two tail ends overlap to form an overlap area 131. Because the overlap area 131 is formed, it can be ensured that the outer surface of the heat insulation body 110 can be wrapped by the insulating encapsulation layer 130, preventing the material in the heat insulation body 110 from leaking from the tail end connection of the insulating encapsulation layer 130. The overlap area 131 is located on the large surface of the heat insulation body 110 to improve the encapsulation effect.

[0090] The overlapping area 131 can extend from one end to the other along the length of the heat insulation body 110. Alternatively, the overlapping area 131 can also extend from one end to the other along the width of the heat insulation body 110. It should be noted that the overlapping area 131 refers to the overlapping area formed by the overlap of two opposite edges of the insulating encapsulation layer 130. For example, when the two long edges of the insulating encapsulation layer 130 overlap, the overlapping area 131 refers to the overlapping area formed by the overlap of the long edges. Even if the long and short edges of the insulating encapsulation layer 130 also overlap, since the long and short edges are not opposite edges, they do not belong to the overlapping area 131. Similarly, when the two short edges of the insulating encapsulation layer 130 overlap, the overlapping area 131 refers to the overlapping area formed by the overlap of the short edges. Even if the long and short edges of the insulating encapsulation layer 130 also overlap, since the long and short edges are not opposite edges, they do not belong to the overlapping area 131.

[0091] The overlapping area 131 and the central area of ​​the insulation body 110 can be avoided to prevent stress concentration due to local thickening, which could cause the fiber skeleton inside the insulation body 110 to collapse.

[0092] Furthermore, the ratio of the area of ​​the overlapping area 131 to the large surface area of ​​the heat insulation body 110 is 0.02 to 0.4. For example, the ratio of the area of ​​the overlapping area 131 to the large surface area of ​​the heat insulation body 110 can be 0.02, 0.05, 0.07, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, etc. This embodiment does not limit the specific value of the above ratio, and those skilled in the art can select it within the range of 0.02 to 0.4 according to their needs.

[0093] The large surface of the heat insulation body 110 is the surface with the largest area. This design can improve the sealing effect and at the same time avoid the overlapping area 131 being too large, occupying the expansion space of the battery 200. This would prevent the overlapping area 131 from being excessively compressed when the battery 200 expands, resulting in a large amount of compression on the heat insulation body 110 corresponding to the overlapping area 131, which would affect the mechanical strength of the battery heat insulation pad 100.

[0094] like Figure 1 As shown in a specific embodiment of this application, the battery heat insulation pad 100 may further include a buffer strip 120, which is disposed on the large surface of the heat insulation body 110, and the large surface of the heat insulation body 110 is the surface with the largest area of ​​the heat insulation body 110. The number of buffer strips 120 can be 2, 3, 4, etc., and this embodiment does not limit the specific number of buffer strips 120. The shape of the buffer strips 120 after arrangement can be set as a square, U-shape, double-line shape, etc. The buffer strips 120 can be bonded to the heat insulation body 110. Furthermore, the buffer strips 120 can be bonded to the surface of the insulating encapsulation layer 130.

[0095] The material of the buffer strip 120 may include at least one of the following: double-sided adhesive, acrylic adhesive, acrylic adhesive, silicone rubber, polyurethane foam, and polyolefin resin foam. The buffer strip 120 can be fixedly connected to the heat insulation body 110 by means of bonding, heat fusion, etc., and can be fixed in strip form on the large surface of the heat insulation body 110.

[0096] The buffer strip 120 has a hollowed-out area that exposes the central area of ​​the large surface of the heat insulation body 110. That is, the buffer strip 120 is disposed on the large surface of the heat insulation body 110, and hollowed-out areas are formed between the buffer strips 120. When the battery heat insulation pad 100 does not include the insulating encapsulation layer 130, the buffer strip 120 is disposed on the large surface of the heat insulation body 110; when the battery heat insulation pad 100 includes the insulating encapsulation layer 130, the buffer strip 120 can be disposed on the insulating encapsulation layer 130. The area of ​​the hollowed-out area / the area of ​​the large surface of the heat insulation body 110 is greater than or equal to 0.5.

[0097] The central area of ​​the battery's surface expands the most. Therefore, the hollow area is set in the central area of ​​the large surface of the heat insulation body 110. In other words, the position of the buffer strip 120 needs to avoid the central area of ​​the large surface of the heat insulation body 110, so that the central area of ​​the large surface of the heat insulation body 110 does not have the buffer strip 120. This can prevent the battery 200 from excessively compressing the battery heat insulation pad 100 due to expansion, and improve the service life of the battery heat insulation pad 100. At the same time, the central area of ​​the large surface of the battery 200 generates a lot of heat. Therefore, the hollow area is set in the central area of ​​the large surface of the heat insulation body 110 to form a heat insulation layer and further improve the heat insulation effect.

[0098] like Figures 6-8 As shown in the illustration, this application also discloses a battery pack, which includes the battery heat insulation pad 100 disclosed in the above embodiment and at least two batteries 200. The battery heat insulation pad 100 is located between the first surfaces of two adjacent batteries 200. The battery pack disclosed in this application, due to having the aforementioned battery heat insulation pad 100, possesses all the technical effects of the aforementioned battery heat insulation pad 100, which will not be elaborated upon here. It should be noted that the battery pack can be placed inside the battery housing 300 to form a battery pack.

[0099] The battery 200 includes a housing 210, a cell 230 disposed inside the housing 210, and an electrolyte.

[0100] Housing 210 is a component used to provide a receiving space to house electrode assemblies and other components and isolate them from the outside environment. Housing 210 generally includes a body with an opening at at least one end and a receiving cavity. The opening of housing 210 can be closed by a cover plate to seal and isolate the internal environment of the battery from the external environment.

[0101] The material of the housing 210 includes at least one of copper, iron, aluminum, stainless steel, and aluminum alloy.

[0102] The terminal assembly is used to electrically connect the electrode assembly (cell 230) located inside the housing 210 to external devices (adjacent batteries or other electrical equipment) located outside the housing 210. The battery 200 can discharge to external devices through the cell output terminal (tab) and the terminal assembly, and an external power source can charge the battery through the terminal assembly and the cell output terminal (tab). The terminal assembly can be directly electrically connected to the cell tab, or it can be electrically connected to the tab through a metal adapter.

[0103] The materials used for the terminal block assembly include, but are not limited to, metals such as copper, aluminum, aluminum alloy, and copper-aluminum alloy.

[0104] The pressure relief valve 240 refers to a component or part that can be actuated to release internal pressure or temperature when the internal pressure or temperature of the battery reaches a predetermined threshold.

[0105] During battery use, the pressure relief valve 240 is mainly used to allow gas inside the battery to be released in order to reduce the internal pressure of the battery in order to prevent the battery from deforming or exploding due to excessive pressure increase when the battery experiences thermal runaway or other situations.

[0106] The pressure relief valve 240 is made of any material, including but not limited to aluminum, steel, alloys, etc. The shape of the pressure relief valve 240 is not limited, such as square, oblong, elliptical, racetrack-shaped, etc. The type of pressure relief valve 240 is not limited, such as a scored explosion-proof valve, where the scored areas include grooves, which can be formed by stamping or laser etching.

[0107] Cell 230 is the component in the battery where electrochemical reactions occur, and it is the smallest unit in the battery 200 capable of carrying out electrochemical reactions such as charging / discharging. Cell 230 typically includes a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. Cell 230 can be a wound core or a stacked core.

[0108] Lithium-ion cells primarily function by the insertion and extraction of lithium ions between the positive and negative electrode plates. In cylindrical cells, a three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0109] The positive electrode is one of the core components in a battery that carries the positive electrode active material. During charging, metal ions (e.g., lithium ions) are released from the positive electrode active material (oxidation reaction), migrate through the electrolyte, and intercalate into the negative electrode. During discharging, metal ions (e.g., lithium ions in a lithium battery) are released from the negative electrode and intercalated into the positive electrode active material (reduction reaction), thus realizing the storage and release of lithium ions.

[0110] A positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. The positive active material includes, but is not limited to, at least one of the following: lithium phosphates, lithium transition metal oxides and their respective modified compounds, or other conventional materials that can be used as positive active materials for batteries. These positive active materials can be used alone or in combination. The lithium phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also abbreviated as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, at least one of lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt aluminum oxides, lithium nickel cobalt manganese oxides, and their modified compounds. Lithium nickel cobalt manganese oxides satisfy the general chemical formula LiNi. x Co y Mn z M f O2, where 0.1 < x < 1, 0.1 < y < 1, 0.1 < z < 1, and x + y + z + f = 1, M is a dopant element, and M includes at least one of Al, Mg, Ti, Zr, B, P, Nb, Ta, W, Zr, and V.

[0111] The positive electrode current collector includes a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. The positive electrode current collector can also include a composite current collector, which may include a polymer material substrate and a metal layer. Composite current collectors are formed by forming a metal material (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.).

[0112] The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene and carbon nanofibers.

[0113] The positive electrode binder includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.

[0114] The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium with a silver-plated surface. The negative electrode current collector may also include a composite current collector, which may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.). The negative electrode active layer includes a negative electrode active material, conductive components, adhesives, etc.

[0115] The negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, and mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-ammonia composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.

[0116] A separator is positioned between the positive and negative electrode plates to separate them and prevent short circuits caused by contact. The separator can be at least one of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF). A coating can also be applied to the separator surface. This coating can be inorganic or organic, wherein the inorganic coating material includes at least one of alumina, silicon dioxide, titanium dioxide, magnesium oxide, zirconium oxide, and boehmite; and the organic coating includes at least one of aramid coating and PVDF coating.

[0117] The battery cell 230 also includes a tab, which is disposed on one side of the positive / negative current collector battery cell and is separately / integrated with the current collector. It is electrically connected to the current collector to conduct the current on the corresponding current collector. When the tab and the current collector are separately disposed, the tab and the current collector can be connected by welding.

[0118] The tabs are made of a highly conductive metallic material (such as copper, aluminum, or nickel). The electrolyte is located between the positive and negative electrodes, acting as a conductor of ions between them. Electrolytes include liquid electrolytes, gel polymer electrolytes, and solid electrolytes; liquid electrolytes refer to electrolytes that are in a liquid state, possessing the function of conducting ions while isolating electrons; liquid electrolytes are composed of solvents, electrolyte salts, additives, and other chemical substances; solvents can be carbonates, carboxylic acid esters, or ethers; electrolyte salts can be lithium salts, sodium salts, or zinc salts; additives can be ethylene carbonate, fluoroethylene carbonate, propylene sulfite, vinyl sulfite, etc.

[0119] Furthermore, the first surface of the battery 200 is the surface with the largest area of ​​the battery casing 210. The casing 210 of the battery 200 generally includes end faces and side faces. The current output terminal of the battery 200 (e.g., the terminal post 220 assembly) is disposed on at least one of the end faces, and the pressure relief assembly is also disposed on one of the end faces of the battery 200. The side faces are the surfaces connecting the two end faces. The surface with the largest area of ​​the battery 200 is the surface with the largest area among the side faces. The larger the area, the greater the outward heat transfer. By placing the battery heat insulation pad 100 on one side of the first surface of the battery 200, the optimal heat insulation effect can be achieved.

[0120] In one specific embodiment of this application, the battery heat insulation pad 100 includes at least two, and at least two batteries 200 are disposed between the at least two battery heat insulation pads 100. This arrangement can better prevent the transfer of radiative heat between the batteries 200 while ensuring the overall space utilization of the battery pack. In this embodiment, the thickness of the battery heat insulation pad 100 is ≥1.5mm, that is, the battery heat insulation pad 100 is kept with a large thickness to achieve better heat insulation protection.

[0121] In a specific embodiment of this application, the battery 200 includes a positive electrode material, a casing 210, and a cell 230 disposed inside the casing 210. The cell 230 generally includes a positive electrode sheet and a negative electrode sheet, with a separator disposed between them. The cell 230 is formed by winding or stacking the positive electrode sheet, the negative electrode sheet, and the separator. The positive electrode sheet includes a positive current collector and a positive electrode material. The positive current collector can be made of metal materials such as aluminum foil, nickel foil, or stainless steel, or a composite foil formed by combining metal and insulating materials. The positive electrode material includes a positive active material, a conductive agent, and a binder. The positive active material includes one or more of lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0122] Similarly, the negative electrode sheet includes a negative electrode current collector and a negative electrode material. The negative electrode current collector can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or it can be a composite foil material formed by combining metal and insulating materials. The negative electrode material includes a negative electrode active material, conductive agent, binder, etc. The negative electrode active material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.

[0123] The separator is an insulating membrane placed between the positive and negative electrode plates to prevent electrons from passing through while allowing ions to pass through. The separator is made of at least one of the following materials: glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, etc.

[0124] In this embodiment, the cathode material comprises a layered transition metal oxide, and x / (A×D) ranges from 0.033 to 16.276. Exemplarily, x / (A×D) can be 0.033, 0.7, 1.2, 1.7, 2.2, 3.2, 4.2, 5.2, 6.2, 7.2, 8.2, 9.2, 10.2, 11.2, 12.2, 13.2, 14.2, 15.2, 16.276, etc. This embodiment does not limit the specific value of x / (A×D), and those skilled in the art can select it within the range of 0.033 to 16.276 according to their needs.

[0125] Layered transition metal oxides are ternary materials, and the cathode material of battery 200 is a ternary material. The thermal runaway temperature is relatively high, so better heat insulation is required. The lower limit of a / (M×D) should be increased so that a / (M×D) can take a value within a larger range to ensure better heat insulation.

[0126] In a specific embodiment of this application, the battery includes a first battery and a second battery. A battery heat insulation pad 100 is disposed between two adjacent first surfaces of the first battery and the second battery. The first battery is charged from 10% SOC to 80% SOC in ≤15 minutes. The second battery is charged from 10% SOC to 80% SOC using a normal charging strategy in >15 minutes. During the entire charging process, the temperature difference between the first surfaces of the first battery and the second battery is ≥5℃, that is, the battery heat insulation pad 100 has a better heat insulation effect.

[0127] Furthermore, the capacity of battery 200 is 50Ah~600Ah. For example, the capacity of battery 200 can be 50Ah, 100Ah, 150Ah, 200Ah, 250Ah, 300Ah, 350Ah, 400Ah, 450Ah, 500Ah, 550Ah, 600Ah, etc. The capacity of battery 200 can be measured in the following way: Place battery 200 in a constant temperature chamber at 25°C and perform the following operations on battery 200: charge at 0.33C to the upper limit voltage, then charge at a constant voltage to the cutoff current of 0.05C; let stand for 30 minutes, then discharge at 0.33C to the lower limit voltage; repeat the above operation 3 times, and use the discharge capacity of the third cycle as the battery's fixed capacity.

[0128] Depending on the different positive electrode active materials, the upper and lower voltage limits need to be adjusted accordingly: LFP - upper limit voltage 3.65V, lower limit voltage 2.5V; NCM - upper limit voltage 4.25V, lower limit voltage 2.5V; LFMP - upper limit voltage 4.25V, lower limit voltage 2.5V; lithium nickel manganese oxide - upper limit voltage 4.8V, lower limit voltage 3.5V.

[0129] The battery 200 includes a housing 210 and a battery cell 230 disposed inside the housing 210. The housing 210 is an external protective structure for the battery cell 230, used to house the battery cell 230 and isolate it from the external environment. The housing 210 is mainly made of metal materials such as aluminum, iron, and steel. Typically, the housing 210 includes a housing body and a battery 200 cover plate encapsulated at the open end of the housing body. One end of the housing body is an open end to facilitate the installation of the battery cell 230 inside the housing 210. To close the opening of the housing body, the housing 210 also includes a battery 200 cover plate disposed on the opening of the housing body. That is, the battery 200 cover plate is a component that covers the opening of the housing body to isolate the housing space of the battery cell 230 from the external environment. The shape of the battery 200 cover plate can be adapted to the shape of the housing body to fit the housing 210. The battery cover can be made of a material with a certain degree of hardness and strength (such as aluminum alloy).

[0130] The housing 210 can be of various shapes and sizes, such as cuboid or hexagonal prism. The shape of the housing 210 can be determined according to the specific shape and size of the battery cell 230. The housing 210 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, and aluminum alloy. The thickness of the first surface of the housing 210 is ≥0.1mm.

[0131] Furthermore, the thickness of the first surface of the housing 210 is ≤0.8mm to avoid excessive thickness that would affect the heat dissipation of the battery cell. This setting can ensure the heat dissipation of the battery cell.

[0132] In one specific embodiment of this application, the material of the housing 210 includes steel. Since steel has a low thermal conductivity, in this embodiment, the thickness of the first surface of the housing 210 is designed to be less than 0.5 mm. That is, the thickness of the housing 210 is designed to be thinner to ensure that the heat of the battery cell 230 can be dissipated to the outside through the housing 210 more quickly.

[0133] In a specific embodiment of this application, the battery 200 includes a housing 210 and a terminal post 220 and a pressure relief valve 240 disposed on the housing 210. The terminal post 220 is a structure in which one end is electrically connected to the output end (such as the tab assembly) of the cell 230, and the other end is used to be electrically connected to an external output end so as to output the electrical energy of the cell 230 to the outside. The material of the terminal post 220 is generally a metal material such as aluminum, aluminum alloy, copper, or copper-aluminum alloy.

[0134] The output terminals of the 230 battery cell are generally tab assemblies. Depending on the polarity, the tab assemblies typically include a positive tab assembly and a negative tab assembly. The positive tab assembly is electrically connected to the positive output terminal of the electrical connection output terminal, and the negative tab assembly is electrically connected to the negative output terminal of the electrical connection output terminal.

[0135] As a key component of the battery 200, the tab assembly is used to transmit the internal current of the cell 230 and draw out the internal current of the cell 230. The material of the tab assembly can be the same as that of the current collector. For example, the tab assembly can be made of at least one of the following: aluminum with silver plating, stainless steel with silver plating, copper, aluminum, nickel, carbon, nickel, or titanium. Furthermore, the tab assembly can be cut from the current collector or it can be a separately formed metal part. It can be understood that the positive tab assembly is electrically connected to the positive electrode plate in the cell 230, and the negative tab assembly is electrically connected to the negative electrode plate in the cell 230.

[0136] The pressure relief valve 240 can be formed directly on one end face of the battery 200 housing 210, or it can be connected to the corresponding end face of the battery 200 housing 210. If the pressure relief valve 240 is connected to one end face of the battery 200 housing 210, a pressure relief port needs to be provided on the corresponding end face of the battery 200 housing 210, and the pressure relief valve 240 is connected to the pressure relief port to seal it. The connection method can be welding or other connection methods.

[0137] The pressure relief valve 240 may include a weak area, configured to open and release pressure when the internal pressure of the battery 200's housing 210 is reached. A groove may be provided on the weak area; when the internal pressure of the housing 210 is reached, the groove breaks, causing the weak area to open and release pressure. When a large amount of gas is generated inside the battery 200 due to abnormal conditions such as overcharging, overheating, or short circuits, causing the internal pressure to rise to a certain level, the pressure generated by the gas will cause the groove to break, resulting in the weak area detaching or bending from the housing 210, thus forming a pressure relief port on the housing 210 to release the pressure inside the battery 200's housing 210.

[0138] The terminal post 220 and the pressure relief valve 240 are respectively disposed on two opposite second surfaces of the housing 210. The second surfaces of the housing 210 are perpendicular to the first surface of the housing 210, and the first surface of the housing 210 is the surface with the largest area. By disposing the terminal post 220 and the pressure relief valve 240 on two opposite second surfaces of the housing 210, high-temperature substances can be prevented from being ejected onto the terminal post 220 when the battery 200 is depressurized, thus avoiding a short circuit and further thermal runaway.

[0139] Furthermore, the range of x / (A×D) is 0.025~16. For example, x / (A×D) can be 0.025, 0.7, 1.4, 2.4, 3.4, 4.4, 5.4, 6.4, 7.4, 8.4, 9.4, 10.4, 11.4, 12.4, 13.4, 14.4, 15.4, 16, etc. This embodiment does not limit the specific value of x / (A×D), and those skilled in the art can select it within the range of 0.025~16 according to their needs. This setting can reduce heat concentration and radiant heat, preventing the structural frame of the battery heat insulation pad 100 from collapsing and affecting its service life.

[0140] This application also discloses a method for preparing a battery, the specific method of which is as follows.

[0141] (1) Preparation of the positive electrode:

[0142] The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., PVDF) are mixed, and solvent NMP (N-Methylpyrrolidone) is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, the positive electrode sheet is obtained by rolling and slitting.

[0143] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98):(4~1):(4~1).

[0144] (2) Preparation of negative electrode:

[0145] The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (SBR)) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, the negative electrode sheet is obtained by rolling and slitting.

[0146] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0147] (3) Preparation of electrolyte:

[0148] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0149] (4) Preparation of the diaphragm:

[0150] Polyethylene film is selected as the diaphragm.

[0151] (5) Preparation of lithium-ion batteries:

[0152] The aforementioned positive electrode sheet, separator, and negative electrode sheet are sequentially wound or stacked to form a bare cell. The bare cell is then placed in a battery casing, which is a prismatic casing. The battery is dried, injected with electrolyte, and then packaged, allowed to stand, formed, and volume-adjusted to obtain a lithium-ion battery.

[0153] In the selection of materials for the aforementioned battery, this application may also select other materials, not limited to those limited by the above preparation method. The positive electrode active material may be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. The conductive agent in the positive electrode sheet may also be selected from one or more of graphite, superconducting carbon, Ketjen black, SuperP, carbon nanotubes, graphene, and carbon nanofibers. The binder in the positive electrode sheet may also be selected from one or more of polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene ternary copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene ternary copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan. The positive electrode current collector may also be selected from one or more of stainless steel with silver plating, stainless steel, aluminum, nickel, carbon electrode, carbon, nickel, and titanium. The positive electrode current collector may also include a composite current collector, which may include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming metallic materials (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.).

[0154] The negative electrode active material can be selected from one or more of the following negative electrode active main materials: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.; the conductive agent in the negative electrode sheet can be selected from one or more of the following: conductive carbon black, conductive graphite, carbon nanotubes, graphene, carbon fiber, etc.; the binder in the negative electrode sheet can be selected from one or more of the following: styrene-butadiene rubber, polyacrylic acid and its salts, sodium alginate, etc.; the thickener in the negative electrode sheet can be selected from one or more of the following: sodium carboxymethyl cellulose, polyacrylonitrile multi-component copolymer, etc.; the negative electrode current collector can also be selected from one or more of the following: stainless steel with silver plating, stainless steel, copper, nickel, carbon electrode, carbon, nickel, titanium, etc.; the negative electrode current collector can also include composite current collectors, which can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.).

[0155] The battery pack manufacturing process is as follows.

[0156] Five batteries prepared by the above method were selected and stacked in a large-face-to-large-face manner. A battery heat insulation pad was placed between adjacent batteries, where the large face is the surface with the largest area on the outer surface of the battery. The terminals of the five batteries were electrically connected by a conductive busbar to achieve series or parallel connection.

[0157] The method for preparing the battery heat insulation pad disclosed in this application is as follows:

[0158] Aerogel, light-blocking agent, fiber and other raw materials are mixed in a certain mass ratio and premixed for 30 to 100 minutes at a speed of 10 to 100 r / min. The mixture is then passed through a 10,000 sieve to remove small particles. The sieved material is then mixed for 5 to 20 minutes at a speed of 800 to 2000 r / min. The mixture is then extruded and encapsulated with an insulating encapsulation layer to obtain a battery heat insulation pad.

[0159] The test method for the mass content of fiber filaments in the thermal insulation body is as follows:

[0160] Disassemble the battery heat insulation pad, remove the insulating encapsulation layer, weigh the heat insulation body using a balance and record it as m1g. Then, sieve the weighed heat insulation body using a multi-layer linear vibrating screen. The multi-layer linear vibrating screen has 3 screen layers, with the upper screen diameter ranging from 5 to 8 mm, the middle screen diameter ranging from 2 to 5 mm, and the lower screen diameter ranging from 0.5 to 2 mm. The vibration amplitude is 1.5 to 4.5 mm, and the vibration frequency is 700 to 1400 times / min. Take the material from the upper, middle, and lower screens, weigh it, and record it as m2g. Test the material in the weighed screen using SEM (scanning electron microscope) and EDS (energy dispersive X-ray spectroscopy). If the material is fibrous and contains at least one of the elements such as Si, Al, Fe, Ca, and Mg, it proves that the heat insulation body contains at least one of glass fiber, ceramic fiber, and basalt fiber. The mass content of the fiber filaments is calculated as (m2 / m1) × 100%.

[0161] The test methods for the mass content of aerogel and light-blocking agent in the thermal insulation body are as follows:

[0162] Disassemble the battery heat insulation pad, remove the insulating encapsulation layer, weigh the heat insulation body using a balance, and record the weight as m1g. Then, sieve the weighed heat insulation body using a multi-layer linear vibrating screen. The multi-layer linear vibrating screen has three screen layers: the upper screen diameter ranges from 5 to 8 mm, the middle screen diameter ranges from 2 to 5 mm, and the lower screen diameter ranges from 0.5 to 2 mm. The vibration amplitude is 1.5 to 4.5 mm, and the vibration frequency is 700 to 1400 times / min. Collect the material passing through the lower screen, recording it as a mixture. Separate the mixture using a turbine air classifier. The classifier wheel speed is controlled at 2000 to 6000 rpm (the specific speed can be selected based on the particle size in the mixture, which can be measured using a scanning electron microscope). Collect the material passing through the classifier wheel. The material passing through the classifier wheel is collected and weighed, recorded as m3g. Simultaneously, the material ejected by the classifier wheel is collected and weighed, recorded as m4g. The material passing through the classifier wheel is tested using SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy). If the material passing through the classifier wheel shows a porous structure in the SEM and contains Si, Al, and Zr elements, then the material passing through the classifier wheel includes aerogel. The mass content of aerogel in the insulation body is (m3 / m1) × 100%. The material ejected by the classifier wheel is measured using XRD (X-ray Diffraction). If the material ejected by the classifier wheel shows a characteristic peak corresponding to a light-blocking agent in the XRD test, then the material ejected by the classifier wheel contains a light-blocking agent. The mass content of the light-blocking agent is (m4 / m1) × 100%.

[0163] The mass content of fiber filaments and light-blocking agent in the thermal insulation body = ((m2+m4) / m1)×100%.

[0164] The method for testing the diameter D of the fiber is as follows:

[0165] Disassemble the battery heat insulation pad, remove the heat insulation body, and test the heat insulation body using a scanning electron microscope (SEM) to measure the diameter of the fiber filaments. Take the average value 10 times and record it as Dμm.

[0166] The method for controlling the diameter D of the fiber is as follows:

[0167] The diameter of the fiber can be adjusted by regulating the viscosity of the spinning solution. The higher the viscosity, the larger the diameter D of the fiber. Alternatively, it can be adjusted by adjusting the diameter of the spinneret. The larger the diameter of the spinneret, the larger the diameter D of the fiber, and the smaller the diameter of the spinneret, the smaller the diameter D of the fiber.

[0168] The test method for the average particle size A of the opacifier is as follows:

[0169] Disassemble the battery heat insulation pad, remove the heat insulation body, and grind 3g of the heat insulation body sample in an 80mm diameter agate mortar for 30 minutes to obtain the ground sample. Prepare 20g / L and 60g / L sucrose aqueous solutions. Add one-third volume of the 60g / L sucrose aqueous solution to a centrifuge tube, and add the same volume of 20g / L sucrose aqueous solution using a pipette. Disperse 0.1g of the ground sample in 2mL of the 20g / L sucrose aqueous solution and sonicate for 5 minutes. Then, add the sucrose aqueous solution containing the ground sample to the centrifuge tube and centrifuge at 3000g relative centrifugal force for 20 minutes. Collect the lower layer liquid, filter, wash, and dry to obtain the opacifier particles. Analyze the opacifier particles using a laser particle size distribution analyzer (Mastersizer). 3000), the particle size distribution is measured by laser diffraction method for particle size distribution (specific steps refer to GB / T19077-2016). The particle size corresponding to the cumulative particle size distribution percentage reaching 50% is the average particle size A of the opacifier particles.

[0170] The method for controlling the average particle size A of the opacifier is as follows:

[0171] The average particle size can be adjusted by the rotation speed during particle grinding and pulverization; the higher the rotation speed, the smaller the average particle size. Alternatively, it can be adjusted by the air flow rate in the air jet mill; the higher the air flow rate, the smaller the average particle size. It can also be adjusted by sieving.

[0172] The test method for the specific surface area of ​​the thermal insulation body is as follows:

[0173] Disassemble the battery heat insulation pad, remove the heat insulation body, and test the specific surface area of ​​the heat insulation body according to GB / T19587-2017, in m². 2 / g.

[0174] The method for testing the pore size between aerogel particles is as follows:

[0175] Disassemble the battery heat insulation pad, remove the heat insulation body, and measure the pore size between the aerogel particles of the heat insulation body according to standard JC / T2518-2019, in nm.

[0176] The fast charging strategy for batteries disclosed in this application is as follows:

[0177] The prepared battery was placed at 25°C for 4 hours until thermal equilibrium was reached. The battery was then charged at a constant current of 0.1C to the upper limit voltage, followed by constant voltage charging until the current was less than or equal to 0.05C. It was then discharged at 0.1C to the lower limit voltage, and this process was repeated three times. The capacity discharged in the third cycle was taken as the battery's discharge capacity. After 10 minutes of rest, the battery was discharged at 1C to 2.5V, then rested for 10 minutes before being charged at 0.33C to 10% SOC. The battery was then first charged at a constant current rate of 4C, and then the charging rate was gradually reduced in 0.2C increments until it reached 0.4C. The cutoff condition for each charge was reaching the upper limit voltage. The charging time between 10% SOC (10%×C) and 80% SOC (80%×C) was recorded. When the positive electrode active material included lithium iron phosphate, the upper limit voltage was 3.65V; when the positive electrode active material included lithium nickel cobalt manganese oxide, the upper limit voltage was 4.25V.

[0178] The normal charging strategy for the battery disclosed in this application is as follows:

[0179] The battery is charged at 0.33C to the upper limit voltage, and then charged at a constant voltage until the cutoff current is less than or equal to 0.05C. When the positive electrode active material includes lithium iron phosphate, the upper limit voltage is 3.65V, and when the positive electrode active material includes lithium nickel cobalt manganese oxide, the upper limit voltage is 4.25V.

[0180] This application discloses two performance testing methods, namely Test Method 1 and Test Method 2. Test Method 1 is the test of adjacent battery temperature, and Test Method 2 is the test of vibration loss rate. The specific test procedures of Test Method 1 and Test Method 2 are as follows.

[0181] Test Method 1: Adjacent Battery Temperature Test (Performance 1).

[0182] According to the above-described battery and battery pack preparation method, one battery pack was prepared for each embodiment and comparative example. In each battery pack, a temperature sensor was set on the surface of the battery adjacent to the end battery, or the temperature of the surface of the battery adjacent to the end battery was measured by an infrared thermometer. That is, the batteries on both sides of the battery heat insulation pad are the first battery and the second battery, the first battery is the end battery, and a battery heat insulation pad is set between the second battery and the first battery. The temperature sensor is located on the surface of the second battery closer to the first battery. The values ​​of x, D and A of the battery heat insulation pad in the battery packs of each embodiment and comparative example are shown in Table 1 below. Apart from this, the rest of the structure is the same. The battery packs of each embodiment and comparative example were subjected to end battery piercing according to the GB / T31485-2015 standard. A high-temperature resistant steel needle with a diameter of 5 mm was used to pierce the end battery on the side of the battery pack with a temperature sensor from a direction perpendicular to the large surface of the battery at a speed of 25 ± 5 mm per second. Timing was started when the end battery thermally ran away. The temperature of the temperature sensor was recorded 3 minutes after the end battery thermally ran away. If the temperature was less than or equal to 80°C, it was considered good. If the temperature was greater than 80°C but less than or equal to 120°C, it was considered qualified. If the temperature was greater than 120°C, it was considered unqualified.

[0183] In this test, the positive electrode active material of the battery was selected from lithium iron phosphate as an example. Other positive electrode materials all met the above test requirements. The mass ratio of positive electrode active material: conductive agent: binder met 96:2:2. The negative electrode active material was selected from artificial graphite. The ratio of negative electrode active material: conductive agent: thickener: binder met 95:2:1:2. The battery pack consisted of 5 batteries connected in series. The bare cells were selected as wound cells. Other cell types all met the above test requirements. The batteries in the battery pack were connected in series. Other connection methods all met the above test requirements.

[0184] Test Method 2: Vibration Loss Rate Test (Performance 2).

[0185] According to the above-described method for preparing batteries and battery packs, one battery pack was prepared for each embodiment and comparative example. In each battery pack, five batteries were connected in series. The values ​​of x, D, and A of the heat insulation pad in the battery packs of each embodiment and comparative example are shown in Table 1 below. Apart from this, the rest of the structures are the same. The battery packs of each embodiment and comparative example were charged at a constant current rate of 1C at 25°C until the voltage of the batteries in the battery pack reached the upper limit voltage. Then, constant voltage charging was switched until the battery current dropped to 0.05C. After standing for 20 minutes, the battery pack was discharged at a constant current rate of 1C until the voltage of the batteries in the battery pack reached the lower limit voltage. After standing for 20 minutes, this cycle was repeated 1000 times. The heat insulation pad was then removed, and the insulating encapsulation layer in the heat insulation pad was removed. The heat insulation board was tested for vibration loss rate according to GB / T34336-2017. If the vibration loss rate is less than or equal to 1%, it is considered good. If the vibration loss rate is greater than 1% and less than or equal to 5%, it is considered qualified. If the vibration loss rate is greater than 5%, it is considered unqualified.

[0186] When the positive electrode active material includes lithium iron phosphate, the upper limit voltage of the battery is 3.6V and the lower limit voltage is 2.5V. When the positive electrode active material includes lithium nickel cobalt manganese oxide, the upper limit voltage of the battery is 4.25V and the lower limit voltage is 2.5V.

[0187] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode materials all meet the above test requirements. The mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2. The negative electrode active material is selected from artificial graphite. The ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2. The bare cell is selected as a wound cell. Other cell forms all meet the above test requirements.

[0188]

[0189] As can be seen from Table 1, in Examples 4-6, Example 8, and Examples 11-19, the value of x / (A×D) ranges from 0.040 to 16.276, which meets the limit range of x / (A×D) of 0.025 to 16.276. After testing, it can be seen that the temperature tests of adjacent batteries are all in good condition.

[0190] In Examples 1-3, 7, 9, and 10, the value of x / (A×D) ranges from 0.025 to 0.035, which satisfies the limit range of x / (A×D) from 0.025 to 16.276 and is on the smaller side of the limit range. After testing, it can be seen that the temperature tests of adjacent batteries are all in a qualified state.

[0191] In Examples 1-3, 7, 9-10, and 12-19, the value of x / (A×D) ranges from 0.025 to 4.375, which satisfies the limited range of x / (A×D) from 0.025 to 16.276 and is on the smaller side of the limited range. After testing, it can be seen that the vibration loss rate test is in good condition.

[0192] In Examples 4-6, 8, and 11, the value of x / (A×D) ranges from 4.535 to 16.276, which satisfies the limit range of x / (A×D) from 0.025 to 16.276. After testing, it can be seen that the vibration loss rate test is qualified.

[0193] In Examples 12-19, the value of x / (A×D) ranges from 0.040 to 4.375, which satisfies the limited range of x / (A×D) from 0.025 to 16.276. After testing, it can be seen that the vibration loss rate test and the adjacent battery temperature test are both in good condition.

[0194] In Comparative Examples 1 and 3, the values ​​of x / (A×D) are 0.017 and 0.018, respectively, which do not meet the limit range of x / (A×D) of 0.025~16.276 and are lower than the lower limit of the limit range of x / (A×D). After testing, it can be seen that although the vibration loss rate test is in good condition, the adjacent battery temperature test is unqualified.

[0195] Comparative Example 2 shows that the value of x / (A×D) is 17.974, which does not meet the limit range of x / (A×D) of 0.025~16.276 and is higher than the upper limit of the limit range of x / (A×D). After testing, it can be seen that although the temperature test of adjacent batteries is in good condition, the vibration loss rate test is unqualified.

[0196] As illustrated in this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0197] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0198] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0199] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A battery heat insulation pad, characterized in that, The device includes a heat insulation body (110), which comprises fiber filaments (113), aerogel (112), and a light-blocking agent (111). The heat insulation matrix is ​​formed by mixing at least the fiber filaments (113) and the aerogel (112). The light-blocking agent (111) comprises multiple particles with an average particle size of μm. The light-blocking agent (111) is used to absorb and scatter infrared radiation. The fiber filaments (113) serve as the skeleton of the heat insulation matrix, and the aerogel (112) is dispersed among the fiber filaments (113). The mass content of the fiber filament (113) and the light-blocking agent (111) in the heat insulation body (110) is x%, the diameter of the fiber filament (113) is D μm, and the range of x / (A×D) is 0.025~16.

276.

2. The battery heat insulation pad according to claim 1, characterized in that, The diameter Dμm of the fiber filament (113) is 3μm~30μm.

3. The battery heat insulation pad according to claim 1, characterized in that, The fiber filament (113) has a mass content of 0.5% to 10% in the heat insulation body (110).

4. The battery heat insulation pad according to claim 1, characterized in that, The fiber filament (113) comprises one or more of glass fiber, ceramic fiber, and basalt fiber.

5. The battery heat insulation pad according to claim 1, characterized in that, The length of the fiber filament (113) is greater than the average particle size A μm of the opaque agent (111).

6. The battery heat insulation pad according to claim 1, characterized in that, The specific surface area of ​​the heat insulation body (110) is 50m². 2 / g~1000m 2 / g.

7. The battery heat insulation pad according to claim 1, characterized in that, The mass content (x%) of the fiber filament (113) and the light-blocking agent (111) in the heat insulation body (110) is 10.5% to 50%.

8. The battery heat insulation pad according to claim 1, characterized in that, The aerogel (112) has a mass content of 50% to 80% in the thermal insulation body (110).

9. The battery heat insulation pad according to claim 1, characterized in that, The aerogel (112) comprises one or more of the following: fumed silica aerogel, fumed silica, alumina aerogel, and zirconia aerogel.

10. The battery heat insulation pad according to claim 1, characterized in that, The aerogel (112) comprises multiple particles, and pores are formed between the particles of the aerogel (112), the pore size being 2nm~70nm.

11. The battery heat insulation pad according to any one of claims 1-10, characterized in that, The light-blocking agent (111) includes one or more of carbon black, silicon carbide, titanium dioxide, zirconium silicate, and zirconium oxide.

12. The battery heat insulation pad according to any one of claims 1-10, characterized in that, The average particle size A μm of the opaque agent (111) ranges from 1 μm to 15 μm.

13. The battery heat insulation pad according to any one of claims 1-10, characterized in that, The light-blocking agent (111), the fiber filament (113), and the aerogel (112) are mixed to form the layered heat-insulating matrix.

14. The battery heat insulation pad according to claim 13, characterized in that, The range of x / (A×D) is 0.025 to 16.

05.

15. The battery heat insulation pad according to claim 13, characterized in that, The mass content (x%) of the fiber filament (113) and the light-blocking agent (111) in the battery heat insulation pad is 10.5% to 48%.

16. The battery heat insulation pad according to any one of claims 1-10, characterized in that, The heat insulation body (110) includes a first heat insulation layer (1120) and a second heat insulation layer (1110) stacked together. The first heat insulation layer (1120) includes a heat insulation matrix formed by mixing at least the fiber filaments (113) and the aerogel (112). The second heat insulation layer (1110) includes a light-blocking agent layer.

17. The battery heat insulation pad according to claim 16, characterized in that, The thickness of the first heat insulation layer (1120) is 0.3mm to 7mm; And / or, The thickness of the second heat insulation layer (1110) is 0.02mm~1mm.

18. The battery heat insulation pad according to any one of claims 1-10, characterized in that, It also includes an insulating encapsulation layer (130), within which the heat insulation body (110) is encapsulated.

19. The battery heat insulation pad according to claim 18, characterized in that, The thickness of the insulating encapsulation layer (130) is 50 μm to 200 μm.

20. The battery heat insulation pad according to claim 18, characterized in that, The insulating encapsulation layer (130) includes at least two end points, which overlap to form an overlap area (131), which is located on the large surface of the heat insulation body (110).

21. The battery heat insulation pad according to claim 20, characterized in that, The ratio of the area of ​​the overlapping area (131) to the area of ​​the large surface of the heat insulation body (110) is 0.02 to 0.4, and the large surface of the heat insulation body (110) is the surface with the largest area of ​​the heat insulation body (110).

22. The battery heat insulation pad according to any one of claims 1-10, characterized in that, It also includes a buffer strip (120), which is disposed on the large surface of the heat insulation body (110). The buffer strip (120) has a hollow area, which exposes the central area of ​​the large surface of the heat insulation body (110). The area of ​​the hollow area / the area of ​​the large surface of the heat insulation body (110) is greater than or equal to 0.

5. The large surface of the heat insulation body (110) is the surface with the largest area of ​​the heat insulation body (110).

23. A battery pack, characterized in that, Includes a battery heat insulation pad (100) as described in any one of claims 1-22 and at least two batteries (200), wherein the battery heat insulation pad (100) is located between the first surfaces of two adjacent batteries (200).

24. The battery pack according to claim 23, characterized in that, The first surface of the battery (200) is the surface with the largest area of ​​the battery (200) casing.

25. The battery pack according to claim 24, characterized in that, The battery heat insulation pad (100) includes at least two, and at least two batteries (200) are disposed at intervals between the at least two battery heat insulation pads (100).

26. The battery pack according to claim 23, characterized in that, The battery (200) includes a positive electrode material comprising a layered transition metal oxide, wherein x / (A×D) ranges from 0.033 to 16.

276.

27. The battery pack according to claim 23, characterized in that, The battery (200) includes a first battery and a second battery. A battery heat insulation pad (100) is disposed between two adjacent first surfaces of the first battery and the second battery. The first battery is charged from 10% SOC to 80% SOC in a charging time of ≤15min. The second battery is charged from 10% SOC to 80% SOC using a normal charging strategy in a charging time of >15min. During the entire charging process, the temperature difference between the first surfaces of the first battery and the second battery is ≥5℃.

28. The battery pack according to claim 26, characterized in that, The capacity of the battery (200) is 50Ah~600Ah.

29. The battery pack according to claim 23, characterized in that, The battery (200) includes a housing (210) and a cell (230) disposed inside the housing (210), wherein the thickness of the first surface of the housing (210) is ≥0.1mm.

30. The battery pack according to claim 29, characterized in that, The shell (210) is made of steel, and the thickness of the first surface of the shell (210) is <0.5mm.

31. The battery pack according to claim 23, characterized in that, The battery (200) includes a housing (210) and terminals (220) and a pressure relief valve (240) disposed on the housing (210). The terminals (220) and the pressure relief valve (240) are respectively disposed on two opposite second surfaces of the housing (210). The second surfaces of the housing (210) are perpendicular to the first surface of the housing (210). The first surface of the housing (210) is the surface with the largest area of ​​the housing (210).

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