Battery assembly and electrical device

Abstract

Provided in the present application are a battery assembly and an electrical device. The battery assembly comprises at least two groups of cell battery packs, and a separator located between two adjacent groups of cell battery packs. The separator comprises a hard calcium silicate board, and the hard calcium silicate board comprises a hard calcium silicate material, the density of the hard calcium silicate plate being greater than 170 kg / m3 and less than 600 kg / m3. The present application can effectively inhibit the problems of heat diffusion and thermal runaway, and improve the thermal safety and other performance of the battery assembly.

Description

Battery assembly and electric device

[0001] The present application claims priority to the Chinese patent application No. 202411293177.5, filed on September 13, 2024, and entitled "Battery assembly and electric device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of electrochemical devices, in particular to a battery assembly and an electric device. BACKGROUND

[0003] In recent years, with the rapid development and technical iteration and upgrading of new energy power batteries and energy storage industries, the high integration of battery assembly (or battery module) systems has brought a substantial increase in battery energy density and driving range, and at the same time, higher requirements have been put forward for the thermal safety of battery assemblies, such as higher requirements for the thermal safety protection of battery assembly systems under various severe working conditions in the life cycle to avoid problems such as battery thermal runaway.

[0004] Specifically, when the battery assembly faces mechanical abuse (such as collision, extrusion, and needle puncture of the electric device (such as a vehicle) using the battery), electrical abuse (such as overcharging, overdischarging, and short circuit), thermal abuse (improper temperature management), and the like, a single or multiple single batteries often cause thermal runaway, and it is necessary to prevent the spread of thermal runaway (i.e., prevent heat diffusion) to avoid thermal runaway of other single batteries and cause more serious thermal safety problems.

[0005] By placing a heat insulation sheet (or a partition plate) between adjacent batteries, heat diffusion can be inhibited to some extent. However, due to the poor heat resistance, high thermal conductivity, and low mechanical strength of existing partition plates, the existing heat insulation sheet has limited improvement effect on inhibiting heat diffusion, and is particularly unsuitable for application to block the heat diffusion between battery groups having multiple single batteries (when the partition plate is spaced between two battery groups, since each battery group has multiple single batteries, the pressure on the partition plate is greater, and when the single batteries in one or several battery groups cause thermal runaway due to mechanical abuse, electrical abuse, thermal abuse, and the like, the temperature generated is also often greater, which is more likely to cause damage to the partition plate, thereby failing to effectively block the heat diffusion to the single batteries in the adjacent battery group, causing the single batteries in the adjacent battery group to cause thermal runaway.

[0006] For example, currently, aerogel thermal insulation sheets (or aerogel separators) are mainly placed between adjacent single batteries to block heat diffusion, and the aerogels used mainly include pre-oxidized fiber aerogels, glass fiber aerogels, and ceramic fiber aerogels. The aerogel thermal insulation sheets are mainly used to solve the heat diffusion of single batteries with low capacity. However, when mechanical abuse (for example, collision of an electrical device (such as a car), multiple batteries (single batteries) are pierced by sharp objects), and high-temperature and high-capacity batteries or battery assemblies occur, the aerogel thermal insulation sheets are easily damaged and cannot effectively inhibit heat diffusion. For example, the thickness of the aerogel separator is reduced due to the extrusion of the battery, and the continuous pressure, high temperature, and heat conditions cause the structure of the aerogel thermal insulation sheet to be damaged, causing the heat generated by the battery that has undergone thermal runaway to spread to the adjacent battery, causing the adjacent battery to exceed its safe temperature, thereby triggering thermal runaway (especially when the aerogel separator is spaced between a battery pack with multiple single batteries, the aerogel separator is extruded by multiple single batteries, and the temperature of the multiple single batteries when thermal runaway occurs is often higher, which is more likely to cause the aerogel separator to be damaged, causing heat to spread to the single batteries in the adjacent battery pack, causing the single batteries in the adjacent battery pack to undergo thermal runaway). SUMMARY

[0007] The present application provides a battery assembly and an electrical device to at least solve the problem that the existing technology cannot effectively inhibit heat diffusion due to the poor heat resistance, high thermal conductivity, and low mechanical strength of the separator.

[0008] In one aspect of the present application, a battery assembly is provided, comprising at least two groups of single battery assemblies, and a separator located between adjacent two groups of single battery assemblies; the separator comprises a hard calcium silicate plate, the hard calcium silicate plate comprises a hard calcium silicate material, and the density of the hard calcium silicate plate is greater than 170 kg / m 3 and less than 600 kg / m 3 .

[0009] According to an embodiment of the present application, the density of the hard calcium silicate plate is 200 kg / m 3 ~ 500 kg / m 3 .

[0010] According to an embodiment of the present application, the density of the hard calcium silicate plate is 300 kg / m 3 ~ 400 kg / m 3 .

[0011] According to an embodiment of the present application, the hard calcium silicate material comprises microspheres formed by hard calcium silicate fibers.

[0012] According to an embodiment of the present application, the diameter of the hard calcium silicate fiber is nanoscale.

[0013] According to an embodiment of the present application, the hard silicate board has a compressive strength greater than or equal to 2 MPa at room temperature and normal pressure.

[0014] According to an embodiment of the present application, the hard silicate board has a compressive strength greater than or equal to 2 MPa after being kept at temperature T1 and normal pressure for 60 min ± 5 min, 600 ℃ ≤ T1 ≤ 1000 ℃.

[0015] According to an embodiment of the present application, the hard silicate board has a compressive strength greater than or equal to 2 MPa after being kept at temperature T2 and pressure P1 for 60 min ± 5 min, 600 ℃ ≤ T2 ≤ 1000 ℃, 1.8 MPa ≤ P1 ≤ 2.4 MPa.

[0016] According to an embodiment of the present application, the hard silicate board has a flexural strength greater than or equal to 1 MPa at room temperature and normal pressure.

[0017] According to an embodiment of the present application, the hard silicate board has an ablation rate less than 10% after being treated at 600 ± 10 ℃ for 60 ± 5 min.

[0018] According to an embodiment of the present application, the hard silicate board has a thermal conductivity less than 0.1 W / m·K at a temperature of 600 ± 10 ℃.

[0019] According to an embodiment of the present application, the hard silicate board has a water content less than 7%.

[0020] According to an embodiment of the present application, the hard silicate board comprises reinforcing fibers, the reinforcing fibers comprising glass fibers and / or plant fibers.

[0021] According to an embodiment of the present application, the hard silicate board comprises an opacifying agent, the opacifying agent comprising one or more of silicon carbide particles, titanium dioxide particles, zirconium dioxide particles, triiron tetroxide particles, potassium hexatitanate whiskers.

[0022] According to an embodiment of the present application, the separator further comprises a packaging film packaging the hard silicate board.

[0023] According to an embodiment of the present application, the packaging film comprises a polymer film.

[0024] According to an embodiment of the present application, the packaging film has a thickness of 10 μm to 100 μm.

[0025] According to an embodiment of the present application, the separator has an insulation resistance greater than or equal to 20 MΩ.

[0026] According to an embodiment of the present application, the separator has a withstand current less than 3 mA.

[0027] According to an embodiment of the present application, the thickness of the separator is 6mm-50mm.

[0028] According to an embodiment of the present application, the thickness of the separator is 13.5mm-28.2mm.

[0029] According to an embodiment of the present application, at least one group of the single battery groups comprises a plurality of single batteries.

[0030] According to another aspect of the present application, a power consuming device is provided, comprising the above battery assembly.

[0031] The battery assembly and the power consuming device provided by the present application adopt a separator to separate the battery assemblies, the separator comprises a hard silicon calcium plate containing hard silicon calcium material, and the density of the hard silicon calcium plate is greater than 170kg / m 3 and less than 600kg / m 3 The separator has good heat resistance, low thermal conductivity, high mechanical strength and other properties, and has good heat insulation capacity. When the single battery in the battery assembly is in thermal runaway due to mechanical abuse, electrical abuse, thermal abuse and other factors, the generated heat can be effectively inhibited from spreading to the adjacent single battery group, thereby avoiding the thermal runaway problem of the single battery in the adjacent single battery group. At the same time, the separator has high mechanical strength and good heat resistance, and is not easy to be damaged by factors such as extrusion of the single battery and high temperature generated by thermal runaway of the single battery, thereby effectively inhibiting heat diffusion. The separator has the advantages of high temperature fire prevention, light weight, high strength, good heat insulation capacity and low cost, and can effectively improve the thermal safety and other properties of the battery assembly. BRIEF DESCRIPTION OF DRAWINGS

[0032] FIG. 1 is a structural schematic diagram of a battery assembly according to an embodiment of the present application;

[0033] FIG. 2 is an XRD spectrum of the hard silicon calcium plate according to Embodiment 1 of the present application (the vertical coordinate is the peak intensity (Intensity));

[0034] FIG. 3 is an SEM image of the hard silicon calcium plate according to Embodiment 1 of the present application;

[0035] FIG. 4 is an SEM image of the hard silicon calcium plate according to Embodiment 1 of the present application.

[0036] Legend: 1: separator; 2: single battery; 201: first group of single battery groups; 202: second group of single battery groups; 203: third group of single battery groups. DETAILED DESCRIPTION

[0037] In order for those skilled in the art to better understand the scheme of the present application, the present application is further described in detail below. The following specific embodiments are only used to describe the principles and characteristics of the present application, and the examples are used to explain the present application, but not to limit the scope of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0038] The present application provides a battery assembly, as shown in Figure 1, which is a structural schematic diagram of a battery assembly according to an embodiment. The battery assembly comprises at least two groups of single battery packs (for example, 201, 202, 203), and a separator 1 located between the two adjacent groups of single battery packs. The separator 1 comprises a hard calcium silicate board, which comprises a hard calcium silicate material, and the density of the hard calcium silicate board is greater than 170 kg / m 3 and less than 600 kg / m 3 .

[0039] In the embodiments of the present application, the above-mentioned separator 1 is used to separate the adjacent single battery packs, which can effectively suppress heat diffusion and improve the thermal safety performance of the battery. Specifically, according to the research of the inventors, the above-mentioned separator 1 has good heat resistance, low thermal conductivity, high mechanical strength and other properties, and has good heat insulation capacity. When the single battery in the battery assembly is in thermal runaway due to mechanical abuse, electrical abuse, thermal abuse and other factors, the generated heat can be effectively suppressed from spreading to the adjacent single battery pack (for example, between 201 and 202, between 202 and 203), thereby avoiding the thermal runaway problem of the single battery 2 in the adjacent single battery pack. At the same time, the separator 1 has high mechanical strength and good heat resistance, and is not easy to be damaged by factors such as high temperature generated by the extrusion of the single battery 2 and the thermal runaway of the single battery 2, thereby effectively suppressing heat diffusion. The separator 1 has the advantages of high temperature fire prevention, light weight, high strength, good heat insulation capacity and low cost, and can effectively improve the thermal safety performance of the battery assembly.

[0040] In the embodiments of the present application, for any single battery pack, it comprises at least one single battery 2, i.e. it can comprise one single battery 2, or a plurality of single batteries 2, for example, 2, 5, 8, 10, 14, 17, 20, 26, 30 or a range between any two of the above numbers, or more.

[0041] In some embodiments, at least one group of single battery packs comprises a plurality of single batteries 2, for example, there are at least two adjacent groups of single battery packs, each of which comprises a plurality of single batteries, and the separator 1 is arranged between the two adjacent groups of battery packs.

[0042] In the related art, due to the poor heat resistance, high thermal conductivity, and low mechanical strength of the existing separators, the existing separators are not suitable for being applied between the single battery groups with multiple single batteries 2. Specifically, when the separators are arranged between two single battery groups with multiple single batteries 2, the pressure on the separators is greater due to the multiple single batteries 2 in each single battery group, and when the single batteries 2 in one or more battery groups are subject to thermal runaway due to mechanical abuse, electrical abuse, thermal abuse, or the like, the temperature generated is also often greater, which is more likely to cause the separators to be damaged, thereby failing to effectively block the heat from spreading to the single batteries 2 in the adjacent battery groups, and causing the single batteries 2 in the adjacent battery groups to be subject to thermal runaway. In the embodiments of the present application, the separators 1 including the hard calcium silicate board can be applied between the single battery groups with multiple single batteries 2, effectively inhibiting the heat spreading problem between such multiple single battery groups with high capacity, and improving the thermal safety and other performances of the battery assembly.

[0043] According to the research and analysis of the inventors, the density of the hard calcium silicate board and the mechanical strength and thermal conductivity coefficient of the hard calcium silicate board have certain correlation. Specifically, the mechanical strength of the hard calcium silicate board tends to decrease with the decrease of the density of the hard calcium silicate board. The greater the density of the hard calcium silicate board, the higher the compaction degree and the greater the thermal conductivity coefficient, thereby making the heat insulation capacity of the hard calcium silicate board worse. When the separators are applied to the battery assembly, the separators not only need to have the required heat insulation capacity, but also need to meet the higher mechanical strength. The main reason is that when the single batteries 2 in the battery assembly are subject to thermal runaway, the temperature in the battery assembly rises, the single batteries 2 in the battery assembly are expanded by heat, and the separators are extruded, resulting in cracks in the separators. When the extrusion force on the separators reaches a critical value (the critical value corresponds to the lower limit critical value of the mechanical strength of the separators), the cracks in the separators penetrate the entire separators, and the heat is transmitted to the single batteries 2 in the adjacent single batteries through the cracks in the separators, further causing the thermal runaway of the adjacent single batteries 2, and the heat insulation effect of the separators is lost.

[0044] The inventors have found that in the battery assembly, the separators 1 including the hard calcium silicate board are arranged between the adjacent single battery groups. When the single batteries 2 in a single battery group are subject to thermal runaway, the density p of the hard calcium silicate board is between 170 kg / m 3 <p<600kg / m 3 When the density p of the hard calcium silicate board is less than 170 kg / m 3When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m

[0045] When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m

[0046] When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m 3 When the density of the hard-silica calcium board is 170 kg / m

[0047] In some embodiments, the capacity of the single battery 2 can be 50 Ah to 350 Ah, for example, 50 Ah, 70 Ah, 90 Ah, 100 Ah, 120 Ah, 140 Ah, 150 Ah, 153 Ah, 170 Ah, 190 Ah, 200 Ah, 210 Ah, 217.1 Ah, 220 Ah, 230 Ah, 240 Ah, 250 Ah, 270 Ah, 290 Ah, 300 Ah, 310 Ah, 326 Ah, 330 Ah, 340 Ah, 350 Ah, or a range consisting of any two of them.

[0048] In some embodiments, the capacity of the single battery 2 can be 50 Ah to 350 Ah, for example, 50 Ah, 70 Ah, 90 Ah, 100 Ah, 120 Ah, 140 Ah, 150 Ah, 153 Ah, 170 Ah, 190 Ah, 200 Ah, 210 Ah, 217.1 Ah, 220 Ah, 230 Ah, 240 Ah, 250 Ah, 270 Ah, 290 Ah, 300 Ah, 310 Ah, 326 Ah, 330 Ah, 340 Ah, 350 Ah, or a range consisting of any two of them.

[0049] In the embodiments of the present application, the monomer battery groups in the battery assembly and the monomer batteries 2 in the monomer battery groups can be connected by conventional methods in the art, and no special limitation is made thereon. For example, for any monomer battery group, when it includes a plurality of monomer batteries 2, the monomer batteries 2 can be electrically connected by conventional methods in the art, such as series connection, parallel connection or mixed connection, etc., and no separator 1 or other structure (see 202 in FIG. 1) is arranged between adjacent monomer batteries 2 in the monomer battery group.

[0050] Further research shows that the density of the above-mentioned hard silicon calcium plate can be 200 kg / m 3 ~ 500 kg / m 3 , which is conducive to further inhibiting the heat diffusion problem of the battery assembly and improving the thermal safety performance of the battery assembly.

[0051] Exemplarily, the density of the hard silicon calcium plate can be 200 kg / m 3 , 250 kg / m 3 , 300 kg / m 3 , 350 kg / m 3 , 400 kg / m 3 , 450 kg / m 3 , 500 kg / m 3 or any two thereof.

[0052] In some preferred embodiments, the density of the hard silicon calcium plate can be 300 kg / m 3 ~ 400 kg / m 3 , which is conducive to further inhibiting the heat diffusion problem of the battery assembly and improving the thermal safety performance of the battery assembly.

[0053] In the embodiments of the present application, the hard silicon calcium stone material can include hard silicon calcium stone fibers, and the diameter of the hard silicon calcium stone fibers can be nanoscale, i.e., the hard silicon calcium plate is a nanometer hard silicon calcium plate, wherein the diameter of the hard silicon calcium stone fibers is generally 50 nm ~ 400 nm, such as 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm or any two thereof.

[0054] Specifically, the xonotlite material is dispersed in the xonotlite plate in a granular form (i.e., the xonotlite plate includes xonotlite particles), and the xonotlite material can include microspheres formed by xonotlite fibers (i.e., the xonotlite particles), which are generally hollow microspheres formed by xonotlite fibers, and the particle size of the microspheres is microns, and the particle size of the microspheres is generally less than or equal to 200 μm, and specifically can be 20 μm to 200 μm, for example, 20 μm, 50 μm, 80 μm, 100 μm, 130 μm, 150 μm, 180 μm, 200 μm, or a range formed by any two of them. The xonotlite plate material has a hollow microsphere structure formed by xonotlite fibers, which is beneficial for heat insulation, can further inhibit the heat diffusion problem of the battery assembly, improve the thermal safety of the battery assembly, and is also beneficial for obtaining a nano xonotlite plate through a hydrothermal dynamic reaction.

[0055] In the embodiments of the present application, the diameter of the xonotlite fiber refers to the average diameter of the xonotlite fiber in the xonotlite plate, and the particle size of the microsphere refers to the average particle size of the microsphere formed by the xonotlite fiber in the xonotlite plate. The existence form of xonotlite in the xonotlite plate (for example, detecting xonotlite fibers and microspheres formed by xonotlite fibers), the average diameter of the xonotlite fiber, and the average particle size of the microsphere formed by the xonotlite fiber, and other characteristics can be measured by scanning electron microscopy (SEM) analysis and other methods.

[0056] In the embodiments of the present application, the crystal structure of xonotlite in the xonotlite plate can be detected and determined by X-ray diffraction (XRD) analysis.

[0057] In some embodiments, the compressive strength σ1 of the above-mentioned xonotlite plate at room temperature (25°C±5°C) and normal pressure (0.1 Mpa) can be greater than or equal to 2 MPa, and σ1 is greater than or equal to 2.4 MPa, for example, which is beneficial for the separator 1 to have high mechanical strength, avoids damage to the separator 1 due to factors such as extrusion of the single battery 2 and high temperature caused by thermal runaway of the single battery 2 in the battery pack, thereby inhibiting the heat diffusion problem of the battery assembly and improving the thermal safety of the battery assembly.

[0058] For example, σ1 is 2 MPa, 2.4 MPa, 2.6 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.2 MPa, 4.5 MPa, 5 MPa, 5.4 MPa, 6 MPa, 6.5 MPa, 7 MPa, 7.5 MPa, 8 MPa, or a range formed by any two of them.

[0059] In some embodiments, the compressive strength σ2 of the above-described hard calcium silicate board after being kept (placed) at temperature T1 under normal pressure for 60 min ± 5 min can be greater than or equal to 2 MPa, 600 ℃ ≤ T1 ≤ 1000 ℃ (i.e., the compressive strength σ2 of the hard calcium silicate board after being treated at high temperature (T1) under normal pressure can be greater than or equal to 2 MPa), for example, greater than or equal to 2.4 MPa, which is conducive to the mechanical strength of the separator 1, avoids damage to the separator 1 due to factors such as extrusion of the single battery 2 and high temperature generated by thermal runaway of the single battery 2 in the battery pack, thereby inhibiting the thermal diffusion problem of the battery assembly and improving the thermal safety of the battery assembly.

[0060] For example, σ2 is 2 MPa, 2.4 MPa, 2.75 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.6 MPa, 6 MPa, 6.5 MPa, 7 MPa, 7.5 MPa, 7.8 MPa, 8 MPa, or a range formed by any two of them.

[0061] Specifically, the compressive strength σ3 of the above-described hard calcium silicate board after being kept (placed) at temperature T2 under pressure P1 for 60 min ± 5 min can be greater than 2 MPa, 600 ≤ T2 ≤ 1000 ℃, 1.8 Mpa ≤ P1 ≤ 2.4 Mpa (i.e., the compressive strength of the hard calcium silicate board after being treated at high temperature (T2) under high pressure (P1) can be greater than 2 MPa), for example, greater than or equal to 2.4 MPa, which is conducive to the mechanical strength of the separator 1, avoids damage to the separator 1 due to factors such as extrusion of the single battery 2 and high temperature generated by thermal runaway of the single battery 2 in the battery pack, thereby inhibiting the thermal diffusion problem of the battery assembly and improving the thermal safety of the battery assembly.

[0062] For example, σ3 is 2 MPa, 2.4 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.2 MPa, 4.5 MPa, 5 MPa, 5.3 MPa, 5.6 MPa, 6 MPa, 6.5 MPa, 7 MPa, 7.3 MPa, 7.5 MPa, or a range formed by any two of them.

[0063] In the embodiments of the present application, the compressive strength σ1 of the hard calcium silicate board at room temperature and normal pressure can be directly measured at room temperature (25 ℃ ± 5 ℃), normal pressure (0.1 Mpa), and normal humidity (40% RH-60% RH); the compressive strength σ2 of the hard calcium silicate board treated at high temperature (T1) under normal pressure can be measured after the hard calcium silicate board is kept at high temperature (T1) under normal pressure for 60 min ± 5 min, and then measured at room temperature, normal pressure, and normal humidity; and the compressive strength σ3 of the hard calcium silicate board treated at high temperature (T2) under high pressure (P1) can be measured after the hard calcium silicate board is kept at high temperature (T2) under high pressure (P1) for 60 min ± 5 min, and then measured at room temperature, normal pressure, and normal humidity.

[0064] Specifically, the above compressive strength (σ1, σ2, σ3) of the hard-silica calcium board can be tested according to GB / T 5486-2008 Inorganic Rigid Thermal Insulation Products-Determination of Compressive Strength. The test is performed under normal temperature, normal pressure, and normal humidity conditions, without the need for pre-drying treatment of the hard-silica calcium board. During the test, a universal testing machine is used to press the hard-silica calcium board sample along the thickness direction of the sample until the sample is destroyed, and the yield strength (stress-strain curve turning point as the yield strength) is read as the compressive strength. The sample size is 100 mm x 100 mm x 30 mm, the loading rate is 10 mm / min, and the inlet force is 5 N.

[0065] In the embodiments of the present application, a conventional universal testing machine in the art can be used, for example, an electronic universal testing machine. In specific implementation, an electronic universal testing machine (10KN) with model AGS-X-10KN can be used. When testing the above compressive strength (σ1, σ2, σ3) of the hard-silica calcium board, the hard-silica calcium board sample can be pressed along the thickness direction of the sample from the pressing surface of the sample until the sample is destroyed, and the yield strength is read as the compressive strength. The pressing surface of the hard-silica calcium board sample refers to the pressing side of the slurry containing hard-silica calcium stone material and other materials used to form the hard-silica calcium board during the pressure filtration molding of the slurry. After pressure filtration molding, the pressing side of the slurry corresponds to the pressing surface of the hard-silica calcium board.

[0066] In addition, the above hard-silica calcium board has a bending strength σ4 of greater than 1 MPa under normal temperature (25°C ± 5°C) and normal pressure, which is beneficial to the separator 1 having high mechanical strength, avoiding damage due to factors such as extrusion of the single battery 2 and high temperature caused by thermal runaway of the single battery 2, thereby inhibiting the thermal diffusion problem of the battery assembly and improving the thermal safety of the battery assembly.

[0067] In the embodiments of the present application, the bending strength σ4 of the hard-silica calcium board under the above conditions can be tested according to GB / T 5486-2008 Inorganic Rigid Thermal Insulation Products-Determination of Compressive Strength. The test is performed under normal temperature, normal pressure, and normal humidity conditions, without the need for pre-drying treatment.

[0068] In the embodiments of the present application, a conventional universal testing machine in the art can be used to test the bending strength of the hard-silica calcium board, for example, an electronic universal testing machine. In specific implementation, an electronic universal testing machine (10KN) with model AGS-X-10KN can be used.

[0069] In addition, the ablation rate w of the hard calcium silicate board after being treated (kept warm) at 600±10℃ for 60±5min is less than 10%, i.e., the ablation rate w of the hard calcium silicate board after long-term temperature resistance is less than 10%, which is beneficial to the heat resistance of the separator 1 and avoids the damage of the separator 1 due to high temperature and other factors caused by thermal runaway of the single battery 2 in the battery pack, thereby inhibiting the heat diffusion problem of the battery assembly and improving the thermal safety of the battery assembly.

[0070] In the embodiments of the present application, the ablation rate w of the hard calcium silicate board can be measured by the following process: weighing the mass m1 of the hard calcium silicate board; then keeping the hard calcium silicate board at 600±10℃ for 60±5min; then weighing the mass m2 of the hard calcium silicate board after keeping warm, and calculating the ablation rate w of the hard calcium silicate board according to w=(m1-m2) / m1.

[0071] In addition, the thermal conductivity of the hard calcium silicate board at a temperature of 600±10℃ can be less than 0.1 W / m·K, which is beneficial to the low thermal conductivity of the separator 1, plays a heat insulation role, inhibits the heat diffusion problem of the battery assembly, and improves the thermal safety of the battery assembly.

[0072] In the embodiments of the present application, the thermal conductivity of the hard calcium silicate board at a temperature of 600±10℃ (i.e., the thermal conductivity of the hard calcium silicate board at 600±10℃) can be measured by referring to YB / T 4130-2005.

[0073] In addition, the water content of the hard calcium silicate board can be less than 7%, for example, less than or equal to 5%, which is beneficial to the better insulation of the hard calcium silicate board, so that the separator between the adjacent two groups of single battery assemblies plays a better insulation role, and further improves the safety and other performances of the battery assembly.

[0074] In the embodiments of the present application, the water content of the hard calcium silicate board=(M1-M2) / M*100%, M1 is the mass of the hard calcium silicate board in a natural state, and M2 is the mass of the hard calcium silicate board after being dried at 110℃±5℃. In specific implementation, the water content of the hard calcium silicate board can be measured by referring to GB / T 5486-2008 Inorganic Hard Insulation Products Test Method. When testing the water content, the mass M1 of the test piece (hard calcium silicate board) in a natural state is weighed by a balance, the test sample is kept in an oven at 110℃ for 3h, then the mass M3 of the test sample is weighed again, then the test sample is continuously dried at 110℃ until the constant mass M4, then it is moved to a dryer and cooled to room temperature. The constant mass criterion is that the change rate of the mass of the test piece in two weighings is less than 0.2% (i.e., (M4-M3) / M3<0.2%), then M3 is taken as the mass M2 of the hard calcium silicate board after being dried at 110℃±5℃, and the water content of the hard calcium silicate board is calculated according to the water content=(M1-M2) / M1*100%.

[0075] In addition, the above-mentioned hard-silica-calcium board can further include reinforcing fibers, and the reinforcing fibers can include glass fibers and / or plant fibers, such as pulp and the like, to improve mechanical strength and the like of the separator 1, suppress heat diffusion of the battery assembly, and improve thermal safety of the battery assembly.

[0076] In addition, the above-mentioned hard-silica-calcium board can further include an additive such as a light shielding agent, and the light shielding agent (anti-infrared radiation material) can include one or more of silicon carbide particles, titanium dioxide particles, zirconium dioxide particles, ferric oxide particles, and potassium titanate whiskers.

[0077] In the embodiments of the present application, the method for preparing the hard-silica-calcium board can include: mixing a silicon source, a calcium source, and water, and then performing a reaction, specifically, performing a hydrothermal dynamic reaction, to synthesize a slurry containing hard-silica-calcium stone (crystals); then adding reinforcing fibers and / or additives and other components to the slurry, and then performing pressure filtration molding (specifically, performing pressure filtration molding using a mold), drying the obtained molded product, and then performing a special processing procedure to obtain a hard-silica-calcium board (hard-silica-calcium stone crystal product) with a preset shape.

[0078] In some embodiments, the reaction temperature of the above-mentioned reaction can be 210°C to 230°C, such as 210°C, 215°C, 220°C, 225°C, 230°C, or a range formed by any two of them, and the reaction time can be 8h to 14h, such as 8h, 10h, 12h, 14h, or a range formed by any two of them.

[0079] Specifically, the above-mentioned reaction is performed in a reaction kettle, and the pressure (i.e., the reaction pressure) of the reaction kettle can be 1.8MPa to 2.4MPa, such as 2MPa. In specific implementation, water vapor can be introduced into the reaction kettle to adjust the pressure of the reaction kettle to the above-mentioned reaction pressure.

[0080] Specifically, in the preparation process of the above-mentioned hard-silica-calcium stone, the drying temperature when the molded product is dried after pressure filtration molding can be 80°C to 170°C, preferably 80°C to 120°C, such as 100°C, and the drying time can be 2 days to 5 days, such as 3 days.

[0081] Specifically, the silicon source can include a silicon dioxide (SiO2) material, and specifically, a silicon dioxide (SiO2) material with a silicon dioxide (SiO2) content of 98% or more can be used.

[0082] Specifically, the calcium source can include a calcium hydroxide material, and specifically, a calcium hydroxide (Ca(OH)2) material with a purity of 90% or more can be used.

[0083] In the embodiments of the present application, the preparation conditions of the xonotlite can be adjusted to control the density, compressive strength (such as σ1, σ2, σ3), flexural strength (σ4), ablation rate (w), and water content of the xonotlite. For example, the reaction temperature and reaction time during the preparation of the xonotlite can be adjusted to control the compressive strength (such as σ1, σ2, σ3) and flexural strength (σ4) of the prepared xonotlite. The drying temperature can be adjusted to control the water content of the prepared xonotlite.

[0084] In addition, the above-mentioned separator 1 can further include a packaging film for packaging the xonotlite plate. The packaging film is wrapped on the outer side of the xonotlite plate, which is beneficial to protect the xonotlite plate and improve the wear resistance and other properties of the separator 1. At the same time, the packaging film can prevent the xonotlite plate from directly contacting the single battery 2 in the battery assembly, thereby avoiding the problems such as the xonotlite plate piercing the single battery 2 due to the generation of powder, and the influence of the water volatilized from the xonotlite plate on the electrochemical performance of the single battery 2, thereby further improving the safety performance and electrochemical performance of the battery assembly.

[0085] Specifically, the packaging film can include a polymer film, such as one (single film) or multiple (composite film) of a multilayer co-extrusion polyolefin heat-shrinkable film (POF), a polyvinyl chloride (PVC) film, a polyethylene (PE) film, a polypropylene (PP) film, and a cross-linked film formed by cross-linking at least two of the polymer materials forming these films.

[0086] In specific implementation, the xonotlite plate can be heat-shrunk and packaged to wrap the packaging film on the surface of the xonotlite plate.

[0087] In some embodiments, the thickness of the packaging film can be 10 μm to 100 μm, such as 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, or a range formed by any two of the above values, and preferably 30 μm to 50 μm.

[0088] In addition, the insulation resistance of the above-mentioned separator 1 can be greater than or equal to 20 MΩ, and further can be greater than or equal to 500 MΩ. The separator 1 has good insulation, which is beneficial to further improve the safety performance of the battery module.

[0089] Generally, when the surface of the xonotlite plate is not provided with the packaging film, the insulation resistance of the separator 1 (also the insulation resistance of the xonotlite plate) is relatively small, for example, 20 to 40 MΩ. When the separator 1 includes the packaging film arranged on the surface of the xonotlite plate, the insulation resistance of the separator 1 is relatively large, specifically greater than or equal to 500 MΩ, which is beneficial to the separator 1 having better insulation, and further improving the electrochemical performance of the battery assembly.

[0090] In addition, the pressure leakage current of the separator 1 can be less than 3 mA, and the use of the separator 1 to separate the single batteries in the battery assembly can further improve the safety performance of the battery assembly.

[0091] In the embodiments of the present application, the insulation resistance of the separator can be tested according to GB / T 31838.4-2019 Solid Insulating Materials-Dielectric and Resistance Properties-Part 4: Resistance Properties (DC Method) Insulation Resistance.

[0092] In the embodiments of the present application, the leakage current (i.e. pressure leakage current) of the separator can be tested according to GB / T 1408.1-2016 Insulating Materials-Test Methods for Electrical Strength-Part 1: Test at Power Frequency.

[0093] In the embodiments of the present application, the compressive strength (σ1, σ2, σ3), the bending strength (σ4), the ablation rate (w), the thermal conductivity, the water content, etc. of the hard silicon separator can be tested after removing the packaging film of the packaged hard silicon calcium plate in the separator 1.

[0094] In some embodiments, the thickness of the separator 1 can be 6 mm to 50 mm, for example, 6 mm, 10 mm, 11 mm, 12 mm, 12.5 mm, 15 mm, 17 mm, 20 mm, 22 mm, 25 mm, 28.2 mm, 28.5 mm, 29 mm, 30 mm, 40 mm, 50 mm, or any range formed by any two of them, preferably 12.5 mm to 28.2 mm.

[0095] The embodiments of the present application also provide a power consuming device comprising the battery assembly described above, which has advantages corresponding to the battery assembly described above, and will not be described again.

[0096] The power consuming device of the embodiments of the present application can be a conventional power consuming device in the art, for example, a power device (such as an electric vehicle, an electric car), an electronic device (such as a mobile phone, a tablet computer, a notebook computer, a digital camera, etc.), a wearable device (such as a watch, a bracelet, VR glasses, etc.), an energy storage power station, etc., which is not particularly limited.

[0097] The present application will be further described below through specific embodiments.

[0098] Embodiment 1

[0099] 1. Preparation of the separator

[0100] The silica material (SiO2 content is more than 98%) and calcium hydroxide material (Ca(OH)2 purity is more than 90%) are added into a batching tank, water is added into the tank, and then a hydrothermal dynamic reaction is carried out in an autoclave (water vapor is introduced into the autoclave during the reaction to make the pressure in the autoclave reach the reaction pressure), to obtain a tobermorite-containing slurry; wherein the reaction temperature is 210°C, the reaction time is 8h, and the reaction pressure is 2Mpa;

[0101] The glass fiber and ferric sesquioxide are added into the tobermorite-containing slurry, and then the slurry is pressure-filtered and formed in a mold, and then the obtained formed product is dried, and then the product is subjected to processes such as profile processing and cutting, to obtain a tobermorite crystal product (i.e., tobermorite plate) with a preset thickness and shape; wherein the thickness of the tobermorite plate is 18mm.

[0102] The tobermorite plate is subjected to heat shrinkage and plastic packaging by using POF, to wrap and package a film (i.e., POF) on the surface of the tobermorite plate, to obtain a separator; wherein the thickness of the packaging film is 30μm.

[0103] 2. Battery assembly and heat diffusion test thereof

[0104] As shown in FIG. 1, the battery assembly is composed of three groups of single battery packs, which are a first group of single battery packs 201, a second group of single battery packs 202, and a third group of single battery packs 203 (i.e., the second group of single battery packs 202 is located between the first group of single battery packs 201 and the third group of single battery packs 203), and each two adjacent single battery packs are separated by a separator 1 (i.e., the first group of single battery packs 201 and the second group of single battery packs 202 are provided with a separator 1, and the second group of single battery packs 202 and the third group of single battery packs 203 are provided with a separator 1), and each group of single battery packs is composed of 17 single batteries 2 (only the single batteries 2 closest to the second group of single battery packs 202 in the first group of single battery packs 201 and the single batteries 2 closest to the second group of single battery packs 202 in the third group of single battery packs 203 are shown in FIG. 1).

[0105] The capacity of the single battery is 217.1 Ah, the length is 625 mm, the width is 130 mm, and the thickness is 18 mm (the size of the separator used is basically the same as that of the single battery); the single battery is charged to a full charge (i.e. 100% SOC) state, the temperature of the single battery and the battery assembly is controlled to be 45°C, the middle single battery in the second group of single battery assemblies (there are 8 single batteries between the middle single battery and the first group of single battery assemblies, and there are 8 single batteries between the middle single battery and the third group of single battery assemblies) is needled at a speed of 1 mm / s until the middle single battery loses control (smoking occurs) and the needling is immediately stopped, then a diffusion time of 15 min is maintained, and then the temperature of each single battery in the second group of single battery assemblies is tested, and the temperature of the single battery closest to the second group of single battery assemblies in the first group of single battery assemblies and the temperature of the single battery closest to the second group of single battery assemblies in the third group of single battery assemblies are tested. The temperature of the 17 single batteries in the second group of single battery assemblies is between 576°C and 891°C, and the temperature of the single battery closest to the second group of single battery assemblies in the first group of single battery assemblies and the temperature of the single battery closest to the second group of single battery assemblies in the third group of single battery assemblies are about 160°C, respectively, indicating that the separator effectively blocks the heat generated by the thermal runaway of the single batteries in the second group of single battery assemblies from diffusing to the single batteries in the first group of single battery assemblies and the third group of single battery assemblies, i.e. the battery assembly does not substantially experience thermal diffusion, and the single batteries in the first group of single battery assemblies and the second group of single battery assemblies do not experience thermal runaway.

[0106] Examples 2 to 4 and Comparative Examples 1 to 2 differ from Example 1 in that the hydrothermal dynamic reaction temperature, reaction time, reaction pressure in the preparation process of the hard-silica calcium board, and the drying temperature, and the density of the hard-silica calcium board, the compressive strength σ1 at normal temperature (25±5°C) and normal pressure, the compressive strength σ2 after keeping at temperature T1 (T1=600°C) and normal pressure for 60 min, the compressive strength σ3 after keeping at temperature T2 (T1=600°C) and pressure P1 (P1=2 MPa) for 60 min, the flexural strength σ4 of the hard-silica calcium board at normal temperature and normal pressure, the ablation rate w of the hard-silica calcium board after keeping at 600°C for 60 min, the thermal conductivity of the hard-silica calcium board at 600°C, the water content of the hard-silica calcium board, the insulation resistance of the separator, the voltage leakage current of the separator, and the like are different, as shown in Tables 1 and 2. Except for the differences shown in Tables 1 and 2, the remaining conditions are the same.

[0107] Example 5: The difference from Example 1 is that (1) each group of single batteries is composed of 14 single batteries, wherein the capacity of the single battery is 153 Ah, the length is 948 mm, the width is 90 mm, and the thickness is 13.5 mm (the size of the separator used is basically the same as that of the single battery); (2) the thickness (13.5 mm) of the hard calcium silicate plate cut is different from Example 1. The rest is the same as Example 1.

[0108] Example 6: The difference from Example 1 is that (1) each group of single batteries is composed of 26 single batteries, wherein the capacity of the single battery is 326 Ah, the length is 880 mm, the width is 113 mm, and the thickness is 28.2 mm (the size of the separator used is basically the same as that of the single battery); (2) the thickness (28.2 mm) of the hard calcium silicate plate cut is different from Example 1. The rest is the same as Example 1.

[0109] Example 7: The difference from Example 1 is that the hard calcium silicate plate is not heat-shrunk and plastic-sealed, that is, the surface of the hard calcium silicate plate is not provided with a packaging film, that is, the separator of Example 7 is a hard calcium silicate plate, but does not include a packaging film. The rest is the same as Example 1.

[0110] Wherein, when testing the compressive strength σ2 of the hard calcium silicate plate after being kept at T1 and normal pressure for 60 min, Table 2 shows the test results at T1 = 600℃, and the compressive strength σ2 measured after the hard calcium silicate plate is kept at normal pressure and a temperature range of 600≤T1≤1000℃ for 60 min±5 min is basically consistent with the test results at T1 = 600℃.

[0111] In addition, when testing the compressive strength σ3 of the hard calcium silicate plate after being kept at T2 and P1 for 60 min, Table 2 shows the test results at T2 = 600℃ and P1 = 2 MPa, and the compressive strength σ3 measured after the hard calcium silicate plate is kept at a temperature range of 600≤T1≤1000℃ and a pressure range of 1.8 Mpa≤P1≤2.4 Mpa for 60 min±5 min is basically consistent with the test results at T2 = 600℃ and P1 = 2 MPa.

[0112] Comparative Example 3: The difference from Example 1 is that the separator in Example 1 is replaced by glass fiber aerogel, the density of the glass fiber aerogel is 240 kg / m 3 , the thickness is 18 mm, the 1 Mpa compression rate is >20%, and the thermal conductivity at 600℃ is 0.1 W / m·K; the rest is the same as Example 1. Wherein, the 1 Mpa compression rate of the glass fiber aerogel is measured according to standard GB / T13480-2014.

[0113] The hard silicon calcium plates of Example 2 to Example 7 were respectively subjected to XRD analysis, and the XRD analysis process of the hard silicon calcium plate was as follows: after the hard silicon calcium plate was ground into powder and transferred to a sample table, the test was performed on an XRD crystal diffraction instrument, and after the test was completed, the spectrum was compared with a standard crystal diffraction pattern to determine the crystal structure of the hard silicon calcium stone in the hard silicon calcium plate.

[0114] Specifically, the hard silicon calcium plates of Example 2 to Example 7 were subjected to XRD analysis, and it was measured that the hard silicon calcium stone material therein was mainly hard silicon calcium stone crystal structure, and it was measured by SEM analysis that the hard silicon calcium stone material in the hard silicon calcium plate was mainly hollow microspheres formed by nanometer hard silicon calcium stone fibers, the particle size of the nanometer hard silicon calcium stone fibers was nanometer level, and the particle size of the hollow microspheres was micron level. Taking the hard silicon calcium stone in Example 1 as an example for further illustration: (1) the XRD spectrum obtained by subjecting the hard silicon calcium plate in Example 1 to XRD test is shown in FIG. 2, and it can be seen from FIG. 2 that the hard silicon calcium plate has hard silicon calcium stone (6CaO·6SiO2·H2O) crystal structure (SiO2 in FIG. 2 represents unreacted silicon dioxide material); (2) the SEM graph obtained by subjecting the hard silicon calcium plate in Example 1 to SEM analysis is shown in FIG. 3 and FIG. 4, and it can be seen from FIG. 3 and FIG. 4 that the hard silicon calcium stone has fiber structure with nanometer level diameter, the nanometer hard silicon calcium stone fibers are agglomerated into hollow microspheres, and the microspheres and fibers are interwoven to form the hard silicon calcium plate.

[0115] Table 1: Hydrothermal dynamic reaction conditions and drying conditions in the process of preparing hard silicon calcium plate

[0116] Table 2: Related parameters of hard silicon calcium plate and separator

[0117] In the process of testing the compressive strength σ3, the hard silicon calcium plate in Example 2 produced a relatively slight crack damage phenomenon (the crack did not penetrate the hard silicon calcium plate), while the hard silicon calcium plate in Comparative Example 1 produced a serious crack damage phenomenon (the crack penetrated the hard silicon calcium plate).

[0118] Table 3: Test results (temperature of single cells in each group of single cell groups after 15 min heat diffusion) Note: In Table 3, “the temperature of 17 single cells in the second group of single cell groups” means that the temperatures of these single cells are within the corresponding temperature range; “the temperature of adjacent single cells” means the temperature of the single cells closest to the second group of single cell groups in the first group of single cell groups and the third group of single cell groups.

[0119] As can be seen from Table 3, in the test results of Comparative Example 1, after the middle monomer battery in the second group of monomer battery packs lost control and stopped needle pricking, and after a diffusion time of 15 min (i.e. after 15 min of heat diffusion), the separator was broken and could not meet the strength requirement, and the temperature of the adjacent monomer battery was as high as 680℃, and thermal runaway occurred.

[0120] In addition, in the test results of Comparative Example 2, after the middle monomer battery in the second group of monomer battery packs lost control and stopped needle pricking, and after a diffusion time of 15 min (i.e. after 15 min of heat diffusion), the temperature of the adjacent monomer battery was as high as 675℃, and the heat diffusion between the monomer battery packs with multiple monomer batteries could not be inhibited, i.e. the multi-cell thermal runaway could not be inhibited.

[0121] In addition, in the test results of Comparative Example 3, after the middle monomer battery in the second group of monomer battery packs lost control and stopped needle pricking, and after a diffusion time of 15 min (i.e. after 15 min of heat diffusion), the glass fiber aerogel was squeezed by the expansion force of the thermal runaway monomer battery, and the thickness of the squeezed glass fiber aerogel was about 14 mm, and the temperature of the adjacent monomer battery was as high as 700℃, and the multi-cell thermal runaway could not be inhibited.

[0122] In contrast to Comparative Examples 1-3, in the battery assemblies of Examples 1-7, by using a hard calcium silicate board with a density greater than 170 kg / m 3 and less than 600 kg / m 3 , when the monomer battery in the second group of monomer battery packs loses thermal control, the heat diffusion can be effectively inhibited, and problems such as thermal runaway of the monomer batteries in the first and third groups of monomer battery packs adjacent to the second group of monomer battery packs can be avoided, thereby improving the thermal safety and other properties of the battery assembly.

[0123] In addition, compared to Examples 2 and 4, Examples 1 and 3 further use a hard calcium silicate board with a density of 300 kg / m 3 to 400 kg / m 3 , which has better mechanical strength and is not prone to breaking even after being treated at high temperature and high pressure, which is conducive to effectively inhibiting heat diffusion while improving the mechanical strength of the separator, and further improving the thermal safety and service life and other properties of the battery assembly.

[0124] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery assembly, wherein, comprising at least two groups of monobloc battery packs, and a separator located between two adjacent groups of the monobloc battery packs; the separator comprises a hard silicone board, the hard silicone board comprises a tobermorite material, the density of the hard silicone board is greater than 170 kg / m 3 and less than 600 kg / m 3 .

2. The battery assembly of claim 1, wherein, The density of the hard silicate board is 200 kg / m 3 ~ 500 kg / m 3 .

3. The battery assembly of claim 2, wherein, The density of the hard silicate board is 300 kg / m 3 ~ 400 kg / m 3 .

4. The battery assembly of claim 1 or 2, wherein, The xonotlite material comprises microspheres formed by xonotlite fibers.

5. The battery assembly of claim 4, wherein, The diameter of the xonotlite fibers is nanoscale.

6. The battery assembly of any one of claims 1-5, wherein, The compressive strength of the xonotlite plate at normal temperature and pressure is greater than or equal to 2 MPa.

7. The battery assembly of any one of claims 1-6, wherein, The compressive strength of the xonotlite plate after being kept at temperature T1 and normal pressure for 60 min±5 min is greater than or equal to 2 MPa, 600℃≤T1≤1000℃.

8. The battery assembly of any one of claims 1-7, wherein, The compressive strength of the xonotlite plate after being kept at temperature T2 and pressure P1 for 60 min±5 min is greater than or equal to 2 MPa, 600℃≤T2≤1000℃, 1.8Mpa≤P1≤2.4Mpa.

9. The battery assembly of any one of claims 1-8, wherein, The flexural strength of the xonotlite plate at normal temperature and pressure is greater than or equal to 1 MPa.

10. The battery assembly of any one of claims 1-9, wherein, The ablation rate of the xonotlite plate after being treated at 600±10℃ for 60±5 min is less than 10%.

11. The battery assembly of any one of claims 1-10, wherein, The thermal conductivity of the xonotlite plate at 600±10℃ is less than 0.1 W / m·K.

12. The battery assembly of any one of claims 1-11, wherein, The water content of the xonotlite plate is less than 7%.

13. The battery assembly of any one of claims 1-12, wherein, The xonotlite plate comprises reinforcing fibers, and the reinforcing fibers comprise glass fibers and / or plant fibers.

14. The battery assembly of any one of claims 1-13, wherein, The xonotlite plate comprises an opacifying agent, and the opacifying agent comprises one or more of silicon carbide particles, titanium dioxide particles, zirconium dioxide particles, ferric oxide particles, and potassium titanate whiskers.

15. The battery assembly of any one of claims 1-14, wherein, The separator further comprises an encapsulation film encapsulating the xonotlite plate.

16. The battery assembly of claim 15, wherein, The encapsulation film comprises a polymer film.

17. The battery assembly of claim 15 or 16, wherein, The thickness of the encapsulation film is 10 μm-100 μm.

18. The battery assembly of any one of claims 1-17, wherein, The insulation resistance of the separator is greater than or equal to 20 MΩ.

19. The battery assembly of any one of claims 1-18, wherein, The pressure leakage current of the separator is less than 3 mA.

20. The battery assembly of any one of claims 1-19, wherein, The thickness of the separator is 6 mm-50 mm.

21. The battery assembly of claim 20, wherein, The thickness of the separator is 13.5 mm-28.2 mm.

22. The battery assembly of any one of claims 1-21, wherein, At least one group of the monomer batteries comprises a plurality of monomer batteries.

23. An electrical device, comprising: The battery assembly comprises the battery assembly of any one of claims 1-22.

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