Heat insulation pad for battery and battery pack

Abstract

The invention discloses a heat insulation pad for a battery and a battery pack, and belongs to the technical field of batteries, the heat insulation pad for the battery comprises aerogel and an opacifying agent, the opacifying agent can absorb and scatter infrared radiation, the aerogel comprises a plurality of particles, gaps are formed among the particles of the aerogel, and the opacifying agent comprises a plurality of particles; the extinction coefficient of the heat insulation plate is Mm < 2 > / kg, the average particle size of particles of the opacifying agent is a [mu] m, the heat insulation plate comprises two opposite target surfaces, the thickness of the heat insulation plate is Dmm, the thickness of the heat insulation plate is the size of the heat insulation plate in the direction perpendicular to the large face of the heat insulation plate, and the range of a / (M * D) is 0.0015-5.8441. According to the heat insulation pad for the battery, the good blocking effect of the heat insulation pad for the battery on heat generated by heat radiation, heat conduction and heat convection can be improved, the heat blocking capacity of the heat insulation pad for the battery is improved, meanwhile, the structural strength of the heat insulation pad for the battery is guaranteed, and the situation that the service life of the heat insulation pad for the battery is affected due to structural collapse is avoided.

Description

Technical Field

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

[0002] As people's demand for longer battery life increases, battery energy density is constantly increasing. Batteries with higher energy density reach higher temperatures during thermal runaway. Ordinary thermal insulation pads are ineffective at high temperatures, leading to rapid thermal runaway of adjacent batteries and causing heat propagation.

[0003] Therefore, how to improve the heat insulation effect and prevent the rapid thermal runaway of adjacent batteries from causing heat propagation 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 heat insulation pad for batteries to improve the heat insulation effect and prevent the rapid thermal runaway of adjacent batteries from causing heat propagation.

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

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

[0007] The first aspect of this application provides a heat insulation pad for batteries, including a heat insulation pad body, the heat insulation pad body including a heat insulation plate, the heat insulation plate including aerogel and a light-blocking agent, the light-blocking agent being able to absorb and scatter infrared radiation, the aerogel including multiple particles, gaps being formed between the aerogel particles, the gaps in the aerogel being able to block heat conduction, and the light-blocking agent including multiple particles.

[0008] The extinction coefficient of the heat insulation board is Mm 2 / kg, the average particle size of the opaque agent is aμm, the heat insulation plate includes two opposing target surfaces, the thickness of the heat insulation plate is Dmm, the thickness of the heat insulation plate is the dimension of the heat insulation plate in the direction perpendicular to the target surface, and a / (M×D) ranges from 0.0015 to 5.8441.

[0009] The target surface of the heat insulation board is the surface with the largest area of ​​the heat insulation board.

[0010] The battery heat insulation pad disclosed in this application incorporates a light-blocking agent into its heat insulation plate. This agent absorbs infrared radiation generated by the battery's thermal radiation, thereby reducing radiative heat transfer between adjacent batteries. The heat insulation plate is also doped with aerogel; due to the gaps between its particles, the aerogel can block heat conduction and heat convection.

[0011] This application controls the average particle size of the light-blocking agent (aμm) and the extinction coefficient (Mm) of the heat insulation board. 2 The weight of the insulation plate and the thickness of the insulation plate (D mm) are selected so that a / (M×D) can be selected within the range of 0.0015~5.8441. This improves the heat insulation pad's ability to block heat generated by heat radiation, heat conduction and heat convection, enhances its heat blocking capacity, and ensures its structural strength to prevent structural collapse and thus extend its service life.

[0012] The selection of a / (M×D) in this application within the range of 0.0015 to 5.8441 avoids problems such as excessively small average particle size of the light-shielding agent, excessively large extinction coefficient of the heat insulation plate, excessive content of light-shielding agent, easy agglomeration between light-shielding agent particles, deterioration of mechanical properties, and shortened service life due to the above relationship being too small. It also avoids problems such as weakened blocking performance of radiative heat due to the above relationship being too large, thermal runaway temperature exceeding 600°C, large amount of heat generated by thermal radiation, and rapid thermal runaway of adjacent batteries.

[0013] 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 target surfaces of two adjacent batteries.

[0014] The battery pack disclosed in the above technical solution has all the technical effects of the aforementioned battery heat insulation pad, and will not be repeated here. Attached Figure Description

[0015] 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.

[0016] Figure 1 This is a schematic diagram of the battery pack structure disclosed in an embodiment of this application;

[0017] Figure 2 This is a schematic diagram of the battery pack structure disclosed in an embodiment of this application;

[0018] Figure 3 This is a schematic diagram of the structure of the battery heat insulation pad disclosed in the embodiments of this application;

[0019] Figure 4 Microscopic images of the aerogel and light-blocking agent disclosed in the embodiments of this application;

[0020] Figure 5 Microscopic images of the aerogel and fibers disclosed in the embodiments of this application;

[0021] Figure 6 This is a cross-sectional view of the heat insulation board disclosed in the embodiments of this application;

[0022] Figure 7 This is a cross-sectional view of a heat insulation panel disclosed in another embodiment of this application;

[0023] Figure 8 This is a cross-sectional view of the heat insulation panel disclosed in another embodiment of this application;

[0024] Figure 9 This is a schematic diagram of the folding of the insulating encapsulation layer disclosed in the embodiments of this application;

[0025] Figure 10 This is a schematic diagram of the battery structure disclosed in an embodiment of this application;

[0026] Figure 11 This is a cross-sectional view of the battery disclosed in an embodiment of this application;

[0027] Figure 12 This is a cross-sectional view of two batteries and a heat insulation pad for batteries disclosed in an embodiment of this application.

[0028] The meanings of the various reference numerals in the figure are as follows:

[0029] 100 - Battery housing;

[0030] 200 - Battery; 210 - Housing; 211 - First surface; 212 - Second surface; 220 - Terminal; 230 - Cell; 240 - Pressure relief valve;

[0031] 300 - Heat insulation pad for batteries; 310 - Heat insulation board; 311 - Light-blocking agent; 312 - Aerogel; 313 - Fiber filament; 3110 - First heat insulation layer; 3120 - Second heat insulation layer; 3130 - Third heat insulation layer; 3140 - Fourth heat insulation layer; 320 - Buffer strip; 330 - Insulating encapsulation layer; 331 - Overlapping area; 340 - Frame; 301 - Hollowed-out area; 302 - Spacing area. Detailed Implementation

[0032] This application discloses a battery heat insulation pad to improve the heat insulation effect and prevent the rapid thermal runaway of adjacent batteries from causing heat spread.

[0033] This application also discloses a battery pack having the above-mentioned heat insulation pad for batteries.

[0034] 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.

[0035] Battery thermal runaway refers to a catastrophic failure phenomenon in which a battery temperature rises rapidly in a short period of time due to a chain reaction of exothermic reactions triggered by various factors, and cannot be controlled by its own heat dissipation, which may eventually lead to fire or explosion.

[0036] Common causes of battery thermal runaway include external forces such as impact, compression, and puncture that damage the internal structure of the battery, causing large-area internal short circuits; and overcharging, over-discharging, and high-current charging and discharging. When a battery is overcharged, the voltage is too high, causing the positive electrode material structure to collapse and the electrolyte to oxidize and decompose, generating a large amount of heat and gas. When a battery is over-discharged, the voltage is too low, which may cause the negative electrode current collector to dissolve, and when it is recharged, it will precipitate and cause an internal short circuit. When a battery is charged and discharged with a high current, excessive Joule heat is generated. If heat is not dissipated in time, it will accumulate and also lead to thermal runaway.

[0037] The battery casing is equipped with a pressure relief component (such as a pressure relief valve). When a large amount of gas is generated inside the battery 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 pressure relief valve to open. At this time, the high-pressure gas inside the battery can be discharged, thereby reducing the internal pressure of the battery and preventing serious safety accidents such as explosion or rupture due to excessive internal pressure. In other words, in the event of battery thermal runaway, the high pressure inside the battery breaks through the pressure relief valve, achieving pressure relief and preventing battery explosion.

[0038] Thermal insulation pads are placed between the batteries in the battery pack. When one battery experiences thermal runaway, ejecting high-temperature flames and gas streams, the thermal insulation pads physically form a barrier, slowing the transfer of heat to adjacent batteries and preventing a chain reaction that could lead to a full-scale fire and explosion of the entire battery pack. The thermal insulation pads also provide a degree of cushioning to compensate for battery expansion and contraction. In other words, the thermal insulation pads are placed between adjacent batteries to prevent heat conduction between them, preventing the thermal runaway of some batteries from spreading to adjacent batteries, thereby suppressing heat propagation within the battery pack.

[0039] The applicant's research revealed that heat transfer between adjacent batteries primarily occurs through conduction, convection, and radiation. During thermal runaway, temperatures typically exceed 600°C. At this temperature, among the three heat transfer mechanisms, radiation exhibits greater heat transfer than conduction and convection. According to the heat transfer formula q = ε × σ × (T1 / T1) 4 -T2 4), where ε is the surface emissivity (ε≥0.85 when the insulation pad material is aerogel, and approximately 0.9 when the insulation pad material is ceramic or glass fiber), and σ is the Stefan-Boltzmann constant (5.67×10⁻⁶). -8 W / (m 2 ·K 4 Let T1 be the surface temperature of the object (i.e., the thermal runaway temperature), and T2 be 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. 4 -T2 4 The exponential variance leads to an exponential increase in heat, causing the thermal runaway battery to rapidly transfer heat to adjacent batteries through thermal radiation.

[0040] Thermal radiation mainly propagates through infrared radiation. Since electromagnetic waves do not require any medium to propagate, the higher the temperature, the greater the radiant heat. The heat radiated by electromagnetic waves is much greater than the heat absorbed by the aerogel in the insulation pad. Traditional insulation pads have poor thermal radiation blocking effect, which leads to rapid thermal runaway of adjacent batteries.

[0041] Based on this, this application discloses a battery heat insulation pad to improve the heat insulation effect and prevent rapid thermal runaway of adjacent batteries from causing heat spread.

[0042] like Figures 2-4 As shown in the illustration, the battery heat insulation pad 300 disclosed in this application includes a heat insulation pad body, which includes a heat insulation plate 310. The heat insulation plate 310 includes aerogel 312 and a light-shielding agent 311. The light-shielding agent 311 can absorb and scatter infrared radiation, that is, reduce the thermal radiation from a high-temperature object to a low-temperature object. The aerogel 312 includes multiple particles, and gaps are formed between the particles of the aerogel 312. The gaps in the aerogel 312 can block heat conduction. When an adjacent battery 200 experiences thermal runaway, the high-temperature thermal runaway gas can be discharged through the pressure relief valve along the corresponding channel. Therefore, the impact of thermal convection on the adjacent battery 200 is less than that of thermal radiation and heat conduction.

[0043] The Dv50 of aerogel 312 particles can range from 7 nm to 25 μm. For example, the Dv50 of aerogel 312 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, 22 μm, 25 μm, etc. This embodiment does not limit the specific value of the Dv50 of aerogel 312 particles; those skilled in the art can select a value within the 7 nm to 25 μm range according to their needs.

[0044] The light-blocking agent 311 comprises multiple particles, the average particle size of which is a μm, and the extinction coefficient of the heat insulation plate 310 is Mm.2 / kg, the heat insulation plate 310 includes two opposing target surfaces, the thickness of the heat insulation plate 310 is D mm, the thickness of the heat insulation plate 310 is the dimension of the heat insulation plate 310 along the direction perpendicular to the target surface of the heat insulation plate 310, the range of a / (M×D) is 0.0015~5.8441, and the target surface of the heat insulation plate 310 is the surface with the largest area of ​​the heat insulation plate 310.

[0045] For example, a / (M×D) can be 0.0015, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 5.8441, etc. This embodiment does not limit the specific value of a / (M×D), and those skilled in the art can select it within the range of 0.0015 to 5.8441 according to their needs.

[0046] The battery heat insulation pad 300 disclosed in this application incorporates a light-blocking agent 311 in its heat insulation plate 310. The light-blocking agent 311 absorbs infrared radiation generated by the thermal radiation of the battery 200, thereby reducing radiative heat transfer between adjacent batteries 200. The heat insulation plate 310 is doped with aerogel 312. Due to the gaps between its particles, the aerogel 312 can block heat conduction and heat convection.

[0047] In this embodiment, the average particle size a μm of the light-blocking agent 311 and the extinction coefficient Mm of the heat insulation plate 310 are controlled. 2 The thickness Dmm of the heat insulation plate 310 is selected such that a / (M×D) is selected within the range of 0.0015~5.8441 to improve the heat insulation pad 300 for batteries, which effectively blocks heat generated by heat radiation, heat conduction and heat convection. This improves the heat insulation capacity of the heat insulation pad 300 for batteries while ensuring the structural strength of the heat insulation pad 300 for batteries, and prevents the structure of the heat insulation pad 300 for batteries from collapsing, which would affect the service life of the heat insulation pad 300 for batteries.

[0048] In this embodiment, a / (M×D) is selected within the range of 0.0015 to 5.8441. This avoids the problems caused by the above relationship being too small, resulting in an excessively small average particle size of the light-blocking agent 311 or an excessively large extinction coefficient of the heat insulation board 310, leading to excessive content of the light-blocking agent 311, which would cause the light-blocking agent 311 particles to easily agglomerate, resulting in poor mechanical properties and shortened service life.

[0049] In this embodiment, a / (M×D) is selected within the range of 0.0015 to 5.8441. This can also avoid the problem that the blocking performance against radiant heat is weakened due to the above relationship being too large, the thermal runaway temperature exceeds 600°C, and the heat generated by thermal radiation is large, which causes the adjacent battery 200 to rapidly thermal runaway.

[0050] When aμm is chosen to be a small value, Mm can be appropriately reduced to avoid problems such as deterioration of mechanical properties and shortened service life. 2 The values ​​of / kg and Dmm ensure that a / (M×D) is within the range of 0.0015 to 5.8441. Similarly, when aμm is chosen to be a large value, Mm can be appropriately increased to prevent a decrease in the blocking performance against radiant heat. 2 The values ​​of / kg and Dmm are set such that a / (M×D) is in the range of 0.0015~5.8441.

[0051] Furthermore, the range of a / (M×D) is 0.0053 to 1.7977. For example, a / (M×D) can be 0.0053, 0.008, 0.04, 0.08, 0.4, 0.8, 1.2, 1.7977, etc. This embodiment does not limit the specific value of a / (M×D), and those skilled in the art can select it within the range of 0.0053 to 1.7977 according to their needs.

[0052] In one specific embodiment of this application, the light-shielding agent 311 may include one or more of carbon black, silicon carbide, titanium dioxide, zirconium silicate, and zirconium oxide. The light-shielding agent 311 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 materials of the light-shielding agent 311, and is not limited to the specific materials disclosed above, as long as they can absorb and dissipate infrared radiation. Those skilled in the art can select the materials of the light-shielding agent 311 based on their needs.

[0053] Given a fixed mass content of the light-blocking agent 311, the smaller the particle size of the light-blocking agent 311, the more infrared radiation it absorbs, the more heat it absorbs from thermal radiation, and the better its heat insulation effect. However, if the average particle size 'a' of the light-blocking agent 311 particles is too small, the particles are prone to agglomeration, resulting in uneven distribution of the light-blocking agent 311 in the heat insulation plate 310, leading to poor mechanical properties of the heat insulation pad. If the average particle size 'a' of the light-blocking agent 311 particles is too large, the blocking effect on thermal radiation is poor.

[0054] Therefore, in a specific embodiment of this application, the average particle size aμm of the opaque agent 311 ranges from 1μm to 15μm. For example, the average particle size aμm of the opaque agent 311 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 311; those skilled in the art can select a value within the range of 1μm to 15μm according to their needs.

[0055] In this embodiment, the average particle size aμm of the light-blocking agent 311 is selected within the range of 1μm to 15μm. This avoids the problem that if the average particle size aμm of the light-blocking agent 311 is too small, the particles of the light-blocking agent 311 will easily agglomerate, resulting in uneven distribution of the light-blocking agent 311 in the heat insulation plate 310 and poor mechanical properties of the heat insulation pad. It also avoids the problem that if the average particle size aμm of the light-blocking agent 311 is too large, the blocking effect on heat radiation will be poor.

[0056] Furthermore, the average particle size aμm of the opacifier 311 is preferably in the range of 2μm to 13μm. For example, the average particle size aμm of the opacifier 311 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, 13μm, etc. This embodiment does not limit the specific value of the average particle size of the opacifier 311; those skilled in the art can select a value within the range of 2μm to 13μm according to their needs.

[0057] The mass content of the light-blocking agent 311 in the heat insulation board 310 can range from 10% to 40%. For example, the mass content of the light-blocking agent 311 in the heat insulation board 310 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 311; those skilled in the art can select a value within the range of 10% to 40% according to their needs.

[0058] In this embodiment, the mass content of the light-blocking agent 311 in the heat insulation plate 310 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 311, 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 311.

[0059] The extinction coefficient Mm of heat insulation board 310 2 The higher the / kg, the greater the proportion of light-blocking agent 311 it contains, and the worse the mechanical properties of the battery heat insulation pad 300; the extinction coefficient Mm of the heat insulation plate 310 2 The smaller the / kg, the smaller the proportion of light-blocking agent 311 it contains, and the worse the heat insulation pad 300 for batteries is at blocking heat radiation.

[0060] Based on this, in this embodiment, Mm 2 The value of / kg can be in the range of 5m. 2 / kg~70m 2 / kg. For example, Mm2 / kg can be 5m 2 / kg, 10m 2 / kg, 15m 2 / kg, 20m 2 / kg, 25m 2 / kg, 30m 2 / kg, 35m 2 / kg, 40m 2 / kg, 45m 2 / kg, 50m 2 / kg, 55m 2 / kg, 60m 2 / kg, 65m 2 / kg, 70m 2 / kg, etc. This example uses Mm 2 The specific value of / kg is not limited; those skilled in the art can adjust it according to requirements within 5m. 2 / kg~70m 2 Choose within the range of / kg.

[0061] This setting can avoid the effect of extinction coefficient Mm 2 The excessively high / kg ratio leads to poor mechanical properties of the 300mm heat insulation pad for batteries; it can also avoid issues related to the extinction coefficient Mm. 2 The low / kg size results in poor heat radiation blocking effect of the 300 heat insulation pad for batteries.

[0062] Furthermore, Mm 2 The optimal range for / kg is 7m. 2 / kg~60m 2 / kg. For example, Mm 2 / kg can be 7m 2 / kg, 11m 2 / kg, 16m 2 / kg, 21m 2 / kg, 26m 2 / kg, 31m 2 / kg, 36m 2 / kg, 41m 2 / kg, 46m 2 / kg, 51m 2 / kg, 56m 2 / kg, 60m 2 / kg, etc. This embodiment refers to Mm. 2 The specific value of / kg is not limited; those skilled in the art can adjust it according to requirements within 7m. 2 / kg~60m 2 Choose within the range of / kg.

[0063] A larger thickness Dmm of the heat insulation plate 310 leads to a greater degree of deformation when subjected to battery pressure. This can cause excessive friction and compression between the aerogel 312 and the light-blocking agent 311 particles, resulting in misalignment of the light-blocking agent 311 and aerogel 312 particles within the heat insulation plate 310. This can also lead to pulverization of the aerogel 312 particles and a decrease in the overall mechanical properties of the heat insulation plate 310. This is especially problematic when the heat insulation plate 310 contains fibers and is covered by an encapsulation layer; under significant deformation, the encapsulation layer is prone to rupture, and the fibers are also prone to breakage, further degrading the overall mechanical properties of the battery heat insulation pad. Conversely, a smaller thickness Dmm of the heat insulation plate 310 indicates a lower total amount of light-blocking agent 311 within the battery heat insulation pad 300, resulting in poorer heat insulation performance.

[0064] Therefore, in this embodiment, the thickness Dmm of the heat insulation board 310 ranges from 0.5mm to 10mm. For example, the thickness Dmm of the heat insulation board 310 can be 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. This embodiment does not limit the specific value of Dmm; those skilled in the art can select a value within the range of 0.5mm to 10mm according to their needs.

[0065] In this embodiment, the thickness Dmm of the heat insulation plate 310 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 300 due to an excessively large thickness Dmm of the heat insulation plate 310, and also avoid the problem of poor heat insulation effect of the battery heat insulation pad 300 due to an excessively small thickness Dmm of the heat insulation plate 310.

[0066] Furthermore, the thickness Dmm of the heat insulation board 310 can be selected within the range of 1mm to 8mm. For example, the thickness Dmm of the heat insulation board 310 can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, etc. This embodiment does not limit the specific value of Dmm; those skilled in the art can select it within the range of 1mm to 8mm according to their needs.

[0067] Furthermore, the thickness Dmm of the heat insulation board 310 can be selected within the range of 2mm to 6mm. For example, the thickness Dmm of the heat insulation board 310 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 of Dmm; those skilled in the art can select it within the range of 2mm to 6mm according to their needs.

[0068] In a specific embodiment of this application, the light-blocking agent 311 and aerogel 312 are mixed to form a heat insulation plate 310. That is, the particles of the light-blocking agent 311 and the particles of the aerogel 312 are mixed evenly to form the heat insulation plate 310. In this way, heat conduction and heat radiation can be blocked and absorbed by the heat insulation plate 310 at the same time, and the range of a / (M×D) can be 0.0040~5.8441.

[0069] For example, in this embodiment, a / (M×D) can be 0.0040, 0.0080, 0.06, 0.12, 0.4, 0.8, 1.2, 1.7, 2.2, 2.6, 3.1, 3.6, 4.1, 4.6, 5.1, 5.6, 5.8441, etc. This embodiment does not limit the specific value of a / (M×D), and those skilled in the art can select it within the range of 0.0040 to 5.8441 according to their needs.

[0070] In this embodiment, since the light-shielding agent 311 and aerogel 312 are mixed together, they can simultaneously block heat conduction and heat radiation in the same layer, resulting in a better heat insulation effect. Therefore, the lower limit of a / (M×D) can be increased to avoid a decrease in the mechanical properties of the battery heat insulation pad 300. Moreover, since the light-shielding agent 311 and aerogel 312 are mixed together, the thickness of the heat insulation plate 310 can be reduced while meeting the heat insulation requirements, thereby reducing the space occupied inside the battery 200.

[0071] like Figure 6 As shown in a specific embodiment of this application, the heat insulation plate 310 includes at least a first heat insulation layer 3110 and a second heat insulation layer 3120. The first heat insulation layer 3110 contains a light-blocking agent 311, and the second heat insulation layer 3120 contains aerogel 312. In this embodiment, the light-blocking agent 311 and the aerogel 312 are distributed in different layers; in other words, the first heat insulation layer 3110 does not contain aerogel 312, and the second heat insulation layer 3120 does not contain light-blocking agent 311.

[0072] In this embodiment, the light-blocking agent 311 and aerogel 312 are distributed in different heat insulation layers. This makes the first heat insulation layer 3110 and the second heat insulation layer 3120 easier to process because they do not need to be mixed with other materials (e.g., aerogel 312 is not needed in the first heat insulation layer 3110 and light-blocking agent 311 is not needed in the second heat insulation layer 3120). In other words, the heat insulation plate 310 containing the first heat insulation layer 3110 and the second heat insulation layer 3120 is easier to process, and the processing quality is easier to ensure because there is no need to control the mass ratio between the components.

[0073] It should be noted that the first heat insulation layer 3110 primarily absorbs heat radiation, while the second heat insulation layer 3120 primarily blocks heat conduction. Of course, the first heat insulation layer 3110 may also contain both a light-blocking agent 311 and aerogel 312, as long as the light-blocking agent 311 is the primary component. Similarly, the second heat insulation layer 3120 may also contain both a light-blocking agent 311 and aerogel 312, as long as the aerogel 312 is the primary component.

[0074] Furthermore, the first heat insulation layer 3110 is coated on the surface (the larger surface area) of the second heat insulation layer 3120. This arrangement reduces the complexity of the manufacturing process. Specifically, after the second heat insulation layer 3120 is prepared, the material of the first heat insulation layer 3110 can be directly coated on the surface of the second heat insulation layer 3120 to form the first heat insulation layer 3110 on the surface of the second heat insulation layer 3120.

[0075] The first heat insulation layer 3110 can be coated only on one surface of the second heat insulation layer 3120, while the first heat insulation layer 3110 is kept on the outermost layer of the heat insulation plate 310, so that the first heat insulation layer 3110 can be closer to the battery to improve the heat conduction barrier effect.

[0076] like Figure 7 As shown, the heat insulation plate 310 may further include a third heat insulation layer 3130, which contains a light-blocking agent 311. A second heat insulation layer 3120 is disposed between the first heat insulation layer 3110 and the third heat insulation layer 3130. In this embodiment, the second heat insulation layer 3120 in the middle is an aerogel layer, while the first heat insulation layer 3110 and the third heat insulation layer 3130 on both sides of the second heat insulation layer 3120 are light-blocking agent layers. This arrangement allows the battery heat insulation pad 300 to have better heat radiation absorption capacity. In addition, since traditional heat insulation pads are all aerogel heat insulation pads, when processing the battery heat insulation pad 300, it is not necessary to change the production line of traditional heat insulation pads. It is only necessary to coat the traditional heat insulation pad base (equivalent to the second heat insulation layer 3120) with light-blocking agent layers (equivalent to the first heat insulation layer 3110 and the third heat insulation layer 3130) on both sides, which reduces processing costs.

[0077] like Figure 8As shown in a specific embodiment of this application, the heat insulation plate 310 may further include a fourth heat insulation layer 3140, which contains aerogel 312. The first heat insulation layer 3110 is disposed between the second heat insulation layer 3120 and the fourth heat insulation layer 3140. In this embodiment, the first heat insulation layer 3110 located in the middle is a light-shielding agent layer, while the second heat insulation layer 3120 and the fourth heat insulation layer 3140 located on both sides of the first heat insulation layer 3110 are aerogel layers. This arrangement allows the first heat insulation layer 3110, which has weaker mechanical properties, to be sandwiched between the second heat insulation layer 3120 and the fourth heat insulation layer 3140, which have better mechanical properties. This ensures that the battery heat insulation pad 300 has better structural strength and prevents the battery heat insulation pad 300 from collapsing, thus affecting its service life.

[0078] In one specific embodiment of this application, the thickness of the first heat insulation layer 3110 can be 0.02mm to 1mm, and the first heat insulation layer 3110 includes a light-blocking agent 311. For example, the thickness of the first heat insulation layer 3110 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 first heat insulation layer 3110; those skilled in the art can select a value within the range of 0.02mm to 1mm according to their needs.

[0079] In this embodiment, the thickness of the first heat insulation layer 3110 is selected within the range of 0.02mm to 1mm. This can avoid the risk of structural performance degradation and structural collapse of the battery heat insulation pad 300 due to excessive thickness of the first heat insulation layer 3110; it can also avoid the problem of poor heat insulation effect due to insufficient thickness of the first heat insulation layer 3110.

[0080] The thickness of the second heat insulation layer 3120 is 0.3mm to 7mm, and the second heat insulation layer 3120 includes aerogel 312. For example, the thickness of the first heat insulation layer 3110 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 second heat insulation layer 3120; those skilled in the art can select a value within the range of 0.3mm to 7mm according to their needs.

[0081] In this embodiment, the thickness of the second heat insulation layer 3120 is selected within the range of 0.3mm to 7mm, which can ensure that the battery heat insulation pad 300 has better structural strength and avoid the collapse of the battery heat insulation pad 300 structure, thus affecting the service life of the battery heat insulation pad 300.

[0082] In one specific embodiment of this application, the aerogel 312 comprises one or more of the following: silica aerogel, fumed silica, alumina aerogel, and zirconia aerogel. Aerogel 312 may consist of only one of the aforementioned materials, or it may consist of a mixture of two or more materials. This embodiment does not limit the specific materials of aerogel 312, and is not limited to the specific materials disclosed above. Those skilled in the art can select the materials for aerogel 312 based on their needs.

[0083] The aerogel 312 particles have pores between them. The larger the pore size, the worse the blocking effect of the battery heat insulation pad 300 on heat conduction and heat convection. The smaller the pore size between the aerogel 312 particles, the better the blocking effect on heat conduction and heat convection. However, when the battery 200 is in normal use, as it charges and discharges, it will transfer the temperature of the battery 200 to the battery heat insulation pad 300. Since the battery heat insulation pad 300 has a better blocking effect on heat conduction and heat convection, it will lock in these temperatures, causing the battery heat insulation pad 300 to be in a high-temperature state for a long time. This will cause the aerogel 312 to break and affect the structural strength of the battery heat insulation pad 300.

[0084] Based on this, in this embodiment, pores are formed between the particles of aerogel 312, and the pore size ranges from 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.

[0085] This design avoids the problem of poor heat conduction and convection blocking effect caused by excessively large pore sizes between aerogel 312 particles; it also avoids the problem of aerogel 312 breaking down and affecting the structural strength of battery heat insulation pad 300 due to excessively small pore sizes between aerogel 312 particles being kept at high temperatures for a long time.

[0086] Furthermore, the mass content of aerogel 312 in the insulation board 310 ranges from 50% to 80%. For example, the mass content of aerogel 312 in the insulation board 310 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 312; those skilled in the art can select a value within the range of 50% to 80% according to their needs.

[0087] In this embodiment, the mass content of aerogel 312 in the heat insulation plate 310 is selected within the range of 50% to 80%. This avoids the problem that if the mass content of aerogel 312 is too high, the content of light-blocking agent 311 will be low, resulting in a poor heat insulation effect of the battery heat insulation pad 300. It also avoids the problem that if the mass content of aerogel 312 is too low, the mechanical properties of the battery heat insulation pad 300 will be poor.

[0088] like Figure 5 As shown in a specific embodiment of this application, the heat insulation board 310 further includes fiber filaments 313, the composition of which includes one or more of glass fiber, ceramic fiber, and basalt fiber. The ceramic fiber can be selected from at least one of aluminosilicate fiber (Al2O3-SiO2), mullite fiber (3Al2O3·2SiO2), alumina fiber (Al2O3), silicon nitride fiber, etc. (Si3N4).

[0089] The fiber filament 313 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 313, and is not limited to the specific materials disclosed above. Those skilled in the art can select the material of the fiber filament 313 based on their needs.

[0090] The diameter of the fiber filament 313 can be from 3μm to 30μm. For example, the diameter of the fiber filament 313 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 313. Those skilled in the art can select it within the range of 3μm to 30μm according to their needs.

[0091] The length of the fiber filament 313 can be from 5mm to 20mm. For example, the length of the fiber filament 313 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 313, and those skilled in the art can select it within the range of 5mm to 20mm according to their needs.

[0092] Adding fiber filaments 313 within the heat insulation plate 310 allows the fiber filaments 313 to form a skeletal structure within the heat insulation plate 310, improving the mechanical strength of the battery heat insulation pad 300. When aerogel 312 is mixed within the heat insulation plate 310, the fiber filaments 313 can provide adhesion and support to the aerogel 312 particles, preventing the aerogel 312 particles from collapsing. Similarly, when aerogel 312 and light-blocking agent 311 are mixed within the heat insulation plate 310, the fiber filaments 313 can provide adhesion and support to the aerogel 312 and light-blocking agent 311 particles, preventing the aerogel 312 and light-blocking agent 311 particles from collapsing.

[0093] Furthermore, the mass content of fiber filament 313 in the insulation board 310 is 0.5% to 10%. For example, the mass content of fiber filament 313 in the insulation board 310 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 313 in the insulation board 310; those skilled in the art can select a value within the range of 0.5% to 10% according to their needs.

[0094] In this embodiment, the mass content of aerogel 312 in the heat insulation plate 310 is selected within the range of 0.5% to 10%. This avoids the problem of insufficient structural strength of the battery heat insulation pad 300 due to too small a mass content of fiber filament 313; it also avoids the problem of insufficient heat insulation effect of the battery heat insulation pad 300 due to too large a mass content of fiber filament 313, which results in good thermal conductivity (strong thermal conductivity but weak heat insulation).

[0095] like Figure 9 As shown in a specific embodiment of this application, the heat insulation pad body further includes an insulating encapsulation layer 330, and the heat insulation plate 310 is encapsulated within the insulating encapsulation layer 330. The material of the insulating encapsulation layer 330 may include at least one of polyethylene terephthalate (PET), polyimide (PI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polycarbonate (PC), etc. The insulating encapsulation layer 330 may be in the form of a thin film, and the insulating encapsulation layer 330 may be adhered to the heat insulation plate 310 by hot melting or adhesive layer.

[0096] Since both aerogel 312 and light-blocking agent 311 are granular structures, the heat insulation plate 310 composed of their mixture is a loose material structure. In this embodiment, the heat insulation plate 310 is encapsulated in an insulating encapsulation layer 330. The insulating encapsulation layer 330 can wrap and encapsulate the loose heat insulation plate 310 to prevent the heat insulation plate 310 from collapsing and improve the structural strength of the battery heat insulation pad 300.

[0097] Furthermore, the thickness of the insulating encapsulation layer 330 is 50μm to 200μm to ensure encapsulation effect and improve mechanical strength. For example, the thickness of the insulating encapsulation layer 330 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 330; those skilled in the art can select a value within the range of 50μm to 200μm according to their needs.

[0098] The thermal conductivity of the insulating encapsulation layer 330 is 0.1 W / (m·K) to 0.7 W / (m·K) to prevent the thermal conductivity of the insulating encapsulation layer 330 from being too high and affecting the heat insulation effect, thus ensuring that the battery heat insulation pad 300 has a better heat insulation effect. For example, the thermal conductivity of the insulating encapsulation layer 330 can be 0.1 W / (m·K), 0.2 W / (m·K), 0.3 W / (m·K), 0.4 W / (m·K), 0.5 W / (m·K), 0.6 W / (m·K), 0.7 W / (m·K), etc. This embodiment does not limit the specific value of the thermal conductivity of the insulating encapsulation layer 330; those skilled in the art can select a value within the range of 0.1 W / (m·K) to 0.7 W / (m·K) according to their needs.

[0099] In one specific embodiment of this application, the insulating encapsulation layer 330 includes at least two terminal ends, which refer to the ends of the insulating encapsulation layer 330. For example, during encapsulation, the heat insulation plate 310 can be placed on the upper side of the insulating encapsulation layer 330 and located in the middle region of the insulating encapsulation layer 330, and then the four ends (i.e., the four terminal ends) of the insulating encapsulation layer 330 are folded towards the upper side of the heat insulation plate 310. Figure 9 The dotted line in the diagram can be understood as the end of the folded-inward end, so that the two ends overlap to form an overlap area 331. Because the overlap area 331 is formed, it can be ensured that the outer surface of the heat insulation plate 310 can be wrapped by the insulating encapsulation layer 330. The overlap area 331 is located on the target surface of the heat insulation plate 310 to improve the encapsulation effect.

[0100] The overlapping area 331 can extend from one end to the other along the length of the heat insulation plate 310. Alternatively, the overlapping area 331 can also extend from one end to the other along the width of the heat insulation plate 310. It should be noted that the overlapping area 331 refers to the overlapping area formed by the overlap of two opposite edges of the insulating encapsulation layer 330. For example, when the two long edges of the insulating encapsulation layer 330 overlap, the overlapping area 331 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 330 also overlap, since the long and short edges are not opposite edges, they do not belong to the overlapping area 331. Similarly, when the two short edges of the insulating encapsulation layer 330 overlap, the overlapping area 331 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 330 also overlap, since the long and short edges are not opposite edges, they do not belong to the overlapping area 331.

[0101] Furthermore, the ratio of the area of ​​the overlapping area 331 to the large surface area of ​​the insulation board 310 is 0.02 to 0.4. For example, the ratio of the area of ​​the overlapping area 331 to the large surface area of ​​the insulation board 310 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; those skilled in the art can select a value within the range of 0.02 to 0.4 according to their needs.

[0102] The width of the overlapping area 331 can be from 5mm to 25mm. For example, the width of the overlapping area 331 can be 5mm, 8mm, 10mm, 13mm, 15mm, 18mm, 20mm, 22mm, 25mm, etc. This embodiment does not limit the specific value of the width of the overlapping area 331, and those skilled in the art can select it within the range of 5mm to 25mm according to their needs.

[0103] The height dimension of the heat insulation board 310 (i.e., the dimension in the height direction after application) can be 60mm to 280mm. For example, the height dimension of the heat insulation board 310 can be 60mm, 80mm, 100mm, 120mm, 140mm, 160mm, 180mm, 200mm, 220mm, 250mm, 280mm, etc. This embodiment does not limit the specific value of the height dimension of the heat insulation board 310. Those skilled in the art can select within the range of 60mm to 280mm according to their needs.

[0104] This design can improve the encapsulation effect while avoiding an excessively large overlapping area 331 that would occupy the expansion space of the battery 200. This would prevent the overlapping area 331 from being overly compressed when the battery 200 expands, resulting in a large amount of compression on the heat insulation plate 310 corresponding to the overlapping area 331, which would affect the mechanical strength of the heat insulation pad 300 for the battery.

[0105] like Figure 3 As shown in a specific embodiment of this application, the battery heat insulation pad 300 further includes a buffer strip 320, which is disposed on the large surface of the heat insulation pad body. The large surface of the heat insulation pad body is the surface with the largest area of ​​the heat insulation pad body.

[0106] The material of the buffer strip 320 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 320 can be fixedly connected to the heat insulation pad body by means of bonding, heat fusion, etc., and can be fixed in strip form on the large surface of the heat insulation pad body.

[0107] The buffer strip 320 exposes the central area of ​​the large surface of the heat insulation pad body, forming a hollow area 301. The buffer strip 320 is disposed on the large surface of the heat insulation pad body, and the hollow area 301 is formed between the buffer strips 320. When the heat insulation pad body does not include the insulating encapsulation layer 330, the buffer strip 320 is disposed on the large surface of the heat insulation plate 310; when the heat insulation pad body includes the insulating encapsulation layer 330, the buffer strip 320 is disposed on the insulating encapsulation layer 330. The area of ​​the hollow area 301 / the area of ​​the large surface of the heat insulation pad body is greater than or equal to 0.5.

[0108] The central area of ​​the large surface of the battery 200 expands the most. Therefore, the hollow area is set in the central area of ​​the large surface of the heat insulation pad body. In other words, the position of the buffer strip 320 needs to avoid the central area of ​​the large surface of the heat insulation pad body, so that the central area of ​​the large surface of the heat insulation pad body does not have the buffer strip 320. This can avoid excessive compression of the battery heat insulation pad 300 by the expansion of the battery 200, and improve the service life of the battery heat insulation pad 300. At the same time, the central area of ​​the large surface of the battery 200 generates serious heat. Setting the hollow area in the central area of ​​the large surface of the heat insulation pad body forms a heat insulation layer, which further improves the heat insulation effect.

[0109] like Figure 1 , Figure 2 and Figure 10 As shown in the embodiments, this application also discloses a battery pack, which includes a battery heat insulation pad 300 as disclosed in the above embodiments and at least two batteries 200. The battery heat insulation pad 300 is located between two adjacent batteries 200, and the surface of the battery 200 facing the battery heat insulation pad 300 is a first surface 211. The battery pack disclosed in this application, due to having the aforementioned battery heat insulation pad 300, possesses all the technical effects of the aforementioned battery heat insulation pad 300, which will not be repeated here. It should be noted that the battery pack can be placed inside the battery housing 100 to form a battery pack.

[0110] The battery 200 includes a housing 210, a cell 230 disposed inside the housing 210, and an electrolyte.

[0111] 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.

[0112] The material of the housing 210 includes at least one of copper, iron, aluminum, stainless steel, and aluminum alloy.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.).

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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 polyvinylidene fluoride (PVDF) coating.

[0128] 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.

[0129] 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 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.

[0130] Furthermore, the first surface 211 of the battery 200 is the surface with the largest area of ​​the battery 200. 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 face is the surface 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 heat transfer outward. Placing the battery heat insulation pad 300 on one side of the first surface 211 of the battery 200 can achieve the optimal heat insulation effect.

[0131] like Figure 11 As shown 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, a binder, etc. The positive active material includes one or more of lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate.

[0132] 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.

[0133] 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.

[0134] In this embodiment, the positive electrode material includes a layered transition metal oxide, the battery 200 has a capacity ≥ 50 Ah, and the a / (M×D) ranges from 0.0015 to 5.7. The layered transition metal oxide includes a ternary material, which includes at least one of lithium nickel cobalt manganese oxide and / or lithium nickel cobalt aluminum oxide, wherein the lithium nickel cobalt manganese oxide satisfies the general 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 doping element, M includes at least one of Al, Mg, Ti, Zr, B, P, Nb, Ta, W, Zr, and V. The battery 200 with a ternary cathode material has a high thermal runaway temperature, so it needs better thermal insulation. The upper limit of a / (M×D) should be reduced so that a / (M×D) can take values ​​within a smaller range to ensure better thermal insulation.

[0135] For example, in this embodiment, a / (M×D) can be 0.0015, 0.02, 0.08, 0.13, 0.53, 1.3, 1.8, 2.3, 2.8, 3.3, 3.8, 4.3, 4.8, 5.3, 5.7, etc. This embodiment does not limit the specific value of a / (M×D), and those skilled in the art can select it within the range of 0.0015 to 5.7 according to their needs.

[0136] In a specific embodiment of this application, the battery includes a first battery and a second battery. A battery heat insulation pad 300 is disposed between two adjacent large 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 211 of the first battery and the second battery is ≥5℃, that is, the battery heat insulation pad 300 has a better heat insulation effect.

[0137] 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).

[0138] 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.

[0139] The thickness of the first surface 211 of the housing 210 (the first surface of the battery is the first surface of the housing 210, i.e. the surface with the larger area on the side of the housing 210) is ≥0.1mm, the thermal conductivity of the first surface 211 of the housing 210 is 15W / (m·K)~240W / (m·K), and the first surface 211 of the housing 210 is the surface with the largest area of ​​the housing 210.

[0140] For example, the thermal conductivity of the first surface 211 of the housing 210 can be 15 W / (m·K), 50 W / (m·K), 80 W / (m·K), 100 W / (m·K), 130 W / (m·K), 150 W / (m·K), 180 W / (m·K), 200 W / (m·K), 220 W / (m·K), 240 W / (m·K), etc. This embodiment does not limit the specific value of the thermal conductivity of the first surface 211 of the housing 210; those skilled in the art can select a value within the range of 15 W / (m·K) to 240 W / (m·K) according to their needs.

[0141] The test method for the thermal conductivity of the first surface 211 of the casing 210 is as follows: disassemble the battery, remove the battery cell, and measure the thermal conductivity of the first surface 211 in accordance with GB / T 3651-2008.

[0142] In one specific embodiment of this application, the housing 210 is made of steel, which has a low thermal conductivity. In this embodiment, the thickness of the first surface 211 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.

[0143] like Figure 12 As shown in a specific embodiment of this application, the heat insulation plate 310 and the first surface 211 of the battery 200 are spaced apart to form a gap region 302 between them, which corresponds to the central region of the first surface 211 of the battery 200. This embodiment does not limit the manner in which the gap is formed between the heat insulation plate 310 and the first surface 211 of the battery 200. For example, a frame 340 can be provided at the edge of the heat insulation plate 310, so that the frame 340 contacts the first surface 211 of the battery 200, ensuring that the heat insulation plate 310 does not contact the first surface 211, thus forming the gap region 302. The ratio of the projected area of ​​the gap region 302 on the first surface 211 of the battery 200 to the area of ​​the first surface 211 is ≥30%.

[0144] Furthermore, the ratio of the projected area of ​​the spacer region 302 on the first surface 211 of the battery 200 to the area of ​​the first surface 211 is ≤95%. This setting can prevent the supporting area of ​​the heat insulation plate 310 and the battery 200 from being too small, thus preventing the heat insulation plate 310 from being crushed under pressure.

[0145] The central region of the battery surface (i.e., the first surface 211) has the largest expansion. By placing the spacer 302 at the position corresponding to the central region of the first surface 211, the spacer 302 is positioned at the position where the battery 200 has the largest expansion. This avoids excessive compression of the battery heat insulation pad 300 by the expansion of the battery 200, thereby improving the service life of the battery heat insulation pad 300. At the same time, the central region of the first surface 211 of the battery 200 generates severe heat. Placing the spacer 302 at the position corresponding to the central region of the first surface 211 further improves the heat insulation effect.

[0146] like Figure 10 and Figure 11 As shown in a specific embodiment of this application, the battery 200 includes a housing 210 and terminals 220 and a pressure relief valve 240 disposed on the housing 210. The terminals 220 are structures in which one end is electrically connected to the output terminal of the battery cell (such as a tab assembly), and the other end is used to electrically connect to an external output terminal to output the electrical energy of the battery cell 230 to the outside. The material of the terminals 220 is generally a metal material such as aluminum, aluminum alloy, copper, or copper-aluminum alloy.

[0147] The output terminal of a battery cell is generally a tab assembly. Depending on the polarity, the tab assembly typically includes 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] The terminal post 220 and the pressure relief valve 240 are respectively disposed on two opposite second surfaces 212 of the housing 210. The second surfaces 212 of the housing 210 are perpendicular to the first surface 211 of the housing 210, and the first surface 211 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 212 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 preventing a short circuit and further thermal runaway.

[0152] This application also discloses a method for preparing a battery, the specific method of which is as follows.

[0153] (1) Preparation of the positive electrode:

[0154] 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, dried at room temperature, and then transferred to an oven for further drying. Finally, the positive electrode sheet is obtained by rolling and slitting.

[0155] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98): (4~1): (4~1).

[0156] (2) Preparation of negative electrode:

[0157] 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.

[0158] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0159] (3) Preparation of electrolyte:

[0160] 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.

[0161] (4) Preparation of the diaphragm:

[0162] Polyethylene film is selected as the diaphragm.

[0163] (5) Preparation of lithium-ion batteries:

[0164] 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.

[0165] 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.).

[0166] 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.).

[0167] The battery pack manufacturing process is as follows:

[0168] Five batteries prepared by the above method were selected and stacked in a large-face-to-large-face manner. A heat insulation pad for the battery was placed between adjacent batteries. 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.

[0169] The method for preparing a battery heat insulation pad disclosed in this application is as follows:

[0170] 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 heat insulation pad for batteries.

[0171] The test method for the mass content of fiber filaments in the insulation board is as follows:

[0172] Disassemble the battery heat insulation pad, remove the insulating encapsulation layer, weigh the heat insulation board using a balance and record it as m1g. Then, sieve the weighed heat insulation board 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 screens 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 Si, Al, Fe, Ca, and Mg, it proves that the heat insulation board 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%.

[0173] The test methods for the mass content of aerogel and light-blocking agent in the insulation board are as follows:

[0174] Disassemble the battery heat insulation pad, remove the insulating encapsulation layer, weigh the heat insulation plate using a balance, and record the weight as m1g. Then, sieve the weighed heat insulation plate 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, labeling 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 weight of the material ejected by the classifying wheel is recorded as m3g. Simultaneously, the weight of the material ejected by the classifying wheel is collected and recorded as m4g. The material passing through the classifying wheel is tested using SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy). If a porous structure is observed in the SEM and the material contains Si, Al, and Zr elements, then the material passing through the classifying wheel includes aerogel. The mass content of aerogel in the insulation board is (m3 / m1) × 100%. The material ejected by the classifying wheel is measured using XRD (X-ray Diffraction). If the material ejected by the classifying wheel shows a characteristic peak corresponding to a light-blocking agent in the XRD test, then the material ejected by the classifying wheel contains a light-blocking agent. The mass content of the light-blocking agent in the insulation board is (m4 / m1) × 100%.

[0175] The test method for the pore size formed between aerogel particles is as follows:

[0176] Disassemble the battery heat insulation pad, remove the insulating encapsulation layer, and measure the pore size between the aerogel particles according to standard JC / T2518-2019, denoted as bnm.

[0177] The fast charging strategy for batteries disclosed in this application is as follows:

[0178] 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 standing for 10 minutes, the battery was discharged at 1C to 2.5V, then stood 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.

[0179] The normal charging strategy for the battery disclosed in this application is as follows:

[0180] 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.

[0181] The test method for the extinction coefficient M of the heat insulation board is as follows:

[0182] Disassemble the battery heat insulation pad, take out the heat insulation plate, make the heat insulation plate into a Φ3.050 mm sample, record the thickness of the sample as I in m, and the mass as m in kg. Use a NEXUS-670 Fourier transform infrared spectrometer (FT-IR) to test the infrared transmittance of the sample. The infrared wavelength used for the test is 2.98 μm. The infrared transmittance of the sample at this wavelength is measured as T. Calculate the extinction coefficient according to formula (1).

[0183] Extinction coefficient (1);

[0184] Where ρ is the density of the sample, in kg / m³, and the extinction coefficient M is in m³. 2 / kg.

[0185] The methods for controlling the extinction coefficient of heat insulation panels are as follows:

[0186] The extinction coefficient can be adjusted by changing the mass content of the light-blocking agent in the insulation board; the higher the mass content of the light-blocking agent, the greater the extinction coefficient. Alternatively, it can be adjusted by regulating the density of the insulation board; the greater the density of the insulation board, the greater the extinction coefficient.

[0187] The test method for the average particle size 'a' of the opacifier is as follows:

[0188] Disassemble the battery heat insulation pad, remove the heat insulation plate, and grind 3g of the heat insulation plate 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.

[0189] The methods for controlling the average particle size 'a' of the opacifier are as follows:

[0190] The average particle size 'a' of the opacifier particles can be adjusted by the rotation speed during particle grinding and pulverization; the higher the rotation speed, the smaller the particle size. Alternatively, it can be adjusted by the airflow rate introduced into the air jet mill; the higher the airflow rate, the smaller the particle size. It can also be adjusted by sieving.

[0191] The test method for the thickness D of the insulation board is as follows:

[0192] The total thickness of the heat insulation pad body was measured using a 0.1μm resolution, ±0.5μm accuracy micrometer and recorded as D1mm. The battery heat insulation pad was disassembled, the heat insulation board was removed, and the thickness of the insulating encapsulation layer was measured using a 0.1μm resolution, ±0.5μm accuracy micrometer and recorded as D2mm. D=D1-2×D2.

[0193] The battery capacity is tested using the following method:

[0194] Place the battery in a constant temperature chamber at 25°C and perform the following operations: charge the battery at 0.33C to the upper limit voltage, then charge it at a constant voltage to the cutoff current of 0.05C; let it stand for 30 minutes, then discharge it 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.

[0195] Depending on the different positive electrode active materials, the upper and lower limit voltages 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.

[0196] 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.

[0197] Test Method 1: Adjacent Battery Temperature Test (Performance 1).

[0198] 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, 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 D, M 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.

[0199] 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.

[0200] Test Method 2: Vibration Loss Rate Test (Performance 2).

[0201] 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 D, M, and a of the heat insulation pads for the batteries in each embodiment and comparative example are shown in Table 1 below. Apart from this, the other 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 for the battery was then removed, and the insulating encapsulation layer in the heat insulation pad was removed. The heat insulation plate 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.

[0202] 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.

[0203] 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.

[0204] Table 1 Comparison of the two performance characteristics

[0205]

[0206] As can be seen from Table 1, in Examples 4-6, Example 8, and Examples 11-20, the value of a / (M×D) ranges from 0.0053 to 5.8441, which meets the limit range of a / (M×D) of 0.0015 to 5.8441. After testing, it can be seen that the vibration loss rate test is in good condition.

[0207] In Examples 1-3, 7, 9, and 10, the value of a / (M×D) ranges from 0.0015 to 0.0044, which satisfies the limited range of a / (M×D) from 0.0015 to 5.8441, and is on the smaller side of the limited range. After testing, it can be seen that the vibration loss rate test is qualified.

[0208] In Examples 1-3, 7, 9, 10, and 12-20, the value of a / (M×D) ranges from 0.0015 to 1.7977, which satisfies the limited range of a / (M×D) from 0.0015 to 5.8441, and is on the smaller side of the limited range. After testing, it can be seen that the temperature tests of adjacent batteries are all in good condition.

[0209] In Examples 4-6, 8, and 11, the value of a / (M×D) ranges from 1.8262 to 5.8441, which satisfies the limited range of a / (M×D) from 0.0015 to 5.8441. After testing, it can be seen that the temperature tests of adjacent batteries are all in a qualified state.

[0210] In Examples 12-20, the value of a / (M×D) ranges from 0.0053 to 1.7977, which meets the specified range of a / (M×D) from 0.0015 to 5.8441 and is in the middle of the specified range. After testing, it can be seen that the vibration loss rate test and the adjacent battery temperature test are both in good condition.

[0211] Comparative Examples 1 and 4 show values ​​of a / (M×D) of 0.0014 and 0.0011, respectively, which do not meet the specified range of a / (M×D) of 0.0015~5.8441 and are lower than the lower limit of the specified range. 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.

[0212] Comparative Examples 2 and 3 show values ​​of a / (M×D) of 5.9921 and 6.1096, respectively, which do not meet the specified range of a / (M×D) of 0.0015~5.8441 and are higher than the upper limit of the specified range. The test results show that although the vibration loss rate test is in good condition, the adjacent battery temperature test is unqualified.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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 heat insulation pad for batteries, characterized in that, The device includes a heat insulation pad body, which includes a heat insulation plate (310). The heat insulation plate (310) includes aerogel (312) and a light-blocking agent (311). The light-blocking agent (311) can absorb and scatter infrared radiation. The aerogel (312) includes multiple particles, and pores are formed between the particles of the aerogel (312). The gaps between the aerogel (312) can block heat conduction. The light-blocking agent (311) includes multiple particles. The extinction coefficient of the heat insulation board (310) is Mm 2 / kg, the average particle size of the opaque agent (311) is aμm, the heat insulation plate (310) includes two opposing target surfaces, the thickness of the heat insulation plate (310) is Dmm, the thickness of the heat insulation plate (310) is the dimension of the heat insulation plate (310) in the direction perpendicular to the target surface, and a / (M×D) ranges from 0.0015 to 5.8441; The target surface of the heat insulation plate (310) is the surface with the largest area of ​​the heat insulation plate (310).

2. The heat insulation pad for batteries according to claim 1, characterized in that, The light-blocking agent (311) includes one or more of carbon black, silicon carbide, titanium dioxide, zirconium silicate, and zirconium oxide.

3. The heat insulation pad for batteries according to claim 1, characterized in that, The average particle size aμm of the opaque agent (311) ranges from 1μm to 15μm.

4. The heat insulation pad for batteries according to claim 1, characterized in that, The light-blocking agent (311) has a mass content of 10% to 40% in the heat insulation board (310).

5. The heat insulation pad for batteries according to claim 1, characterized in that, The light-blocking agent (311) and the aerogel (312) are mixed to form the heat insulation plate (310), and the range of a / (M×D) is 0.0040~5.8441.

6. The battery heat insulation pad according to claim 1, characterized in that, The heat insulation panel (310) includes at least a first heat insulation layer (3110) and a second heat insulation layer (3120), wherein the first heat insulation layer (3110) contains the light-blocking agent (311) and the second heat insulation layer (3120) contains the aerogel (312).

7. The heat insulation pad for batteries according to claim 6, characterized in that, The first heat insulation layer (3110) is coated on the surface of the second heat insulation layer (3120).

8. The heat insulation pad for batteries according to claim 6, characterized in that, The heat insulation panel (310) further includes a third heat insulation layer (3130), which contains a light-blocking agent (311), and a second heat insulation layer (3120) is disposed between the first heat insulation layer (3110) and the third heat insulation layer (3130).

9. The heat insulation pad for batteries according to claim 6, characterized in that, The heat insulation panel (310) further includes a fourth heat insulation layer (3140), which contains aerogel (312), and the first heat insulation layer (3110) is disposed between the second heat insulation layer (3120) and the fourth heat insulation layer (3140).

10. The heat insulation pad for batteries according to claim 6, characterized in that, The thickness of the first heat insulation layer (3110) is 0.02mm~1mm; And / or, The thickness of the second heat insulation layer (3120) is 0.3mm to 7mm.

11. The heat insulation pad for batteries according to any one of claims 1-10, characterized in that, The aerogel (312) comprises one or more of the following: silica aerogel, fumed silica, alumina aerogel, and zirconia aerogel.

12. The heat insulation pad for batteries according to claim 11, characterized in that, The pore size range of the pores formed between the particles of the aerogel (312) is 2nm to 70nm.

13. The heat insulation pad for batteries according to claim 11, characterized in that, The aerogel (312) in the insulation plate (310) has a mass content ranging from 50% to 80%.

14. The heat insulation pad for batteries according to any one of claims 1-10, characterized in that, The heat insulation board (310) also includes fiber filaments (313), the components of which include one or more of glass fiber, ceramic fiber, and basalt fiber.

15. The heat insulation pad for batteries according to claim 14, characterized in that, The fiber filament (313) has a mass content of 0.5% to 10% in the heat insulation board (310).

16. The heat insulation pad for batteries according to any one of claims 1-10, characterized in that, The heat insulation pad body also includes an insulating encapsulation layer (330), and the heat insulation plate (310) is encapsulated within the insulating encapsulation layer (330).

17. The heat insulation pad for batteries according to claim 16, characterized in that, The thickness of the insulating encapsulation layer (330) is 50μm to 200μm; And / or, The thermal conductivity of the insulating encapsulation layer (330) is 0.1 W / (m·K) to 0.7 W / (m·K).

18. The heat insulation pad for batteries according to claim 16, characterized in that, The insulating encapsulation layer (330) includes at least two end points, which overlap to form an overlap area (331) located on the target surface of the heat insulation plate (310).

19. The heat insulation pad for batteries according to claim 18, characterized in that, The ratio of the area of ​​the overlapping area (331) to the large surface area of ​​the heat insulation board (310) is 0.02 to 0.

4.

20. The heat insulation pad for batteries according to any one of claims 1-10, characterized in that, Mm 2 The value of / kg ranges from 5m. 2 / kg~70m 2 / kg; And / or, The value of Dmm ranges from 0.5mm to 10mm.

21. The heat insulation pad for batteries according to any one of claims 1-10, characterized in that, It also includes a buffer strip (320), which is disposed on the large surface of the heat insulation pad body. The buffer strip (320) exposes the central area of ​​the large surface of the heat insulation pad body to form a hollow area (301). The area of ​​the hollow area (301) / the area of ​​the large surface of the heat insulation pad body is greater than or equal to 0.

5. The large surface of the heat insulation pad body is the surface with the largest area of ​​the heat insulation pad body.

22. A battery pack, characterized in that, Includes a battery heat insulation pad (300) as described in any one of claims 1-21 and at least two batteries (200), wherein the battery heat insulation pad (300) is located between two adjacent batteries (200), and the surface of the battery (200) facing the battery heat insulation pad (300) is a first surface (211).

23. The battery pack according to claim 22, characterized in that, The first surface (211) of the battery (200) is the surface with the largest area of ​​the battery (200).

24. The battery pack according to claim 22, characterized in that, The battery (200) includes a positive electrode material, which includes a layered transition metal oxide, and the battery (200) has a capacity ≥50Ah and an a / (M×D) range of 0.0015~5.

7.

25. The battery pack according to claim 22, characterized in that, The battery (200) includes a first battery and a second battery. A heat insulation pad (300) for the battery is disposed between 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 surface (211) of the first battery and the second battery is ≥5℃.

26. The battery pack according to claim 22, characterized in that, The battery (200) includes a housing (210) and a cell (230) disposed inside the housing (210). The thickness of the first surface (211) of the housing (210) is ≥0.1mm, and / or the thermal conductivity of the first surface (211) of the housing (210) is 15W / (m·K)~240W / (m·K). The first surface (211) of the housing (210) is the surface with the largest area of ​​the housing (210).

27. The battery pack according to claim 26, characterized in that, The shell (210) is made of steel, and the thickness of the first surface (211) of the shell (210) is <0.5mm.

28. The battery pack according to claim 22, characterized in that, The heat insulation plate (310) is spaced apart from the first surface (211) of the battery (200) to form a gap area (302) between them. The gap area (302) corresponds to the central area of ​​the first surface (211) of the battery (200). The ratio of the projected area of ​​the gap area (302) on the first surface (211) of the battery (200) to the area of ​​the first surface (211) is ≥30%.

29. The battery pack according to claim 22, 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 (212) of the housing (210). The second surfaces (212) of the housing (210) are perpendicular to the first surface (211) of the housing (210). The first surface (211) of the housing (210) is the surface with the largest area of ​​the housing (210).

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