A battery, a battery pack, and an electric device

Abstract

The application provides a battery, a battery pack and an electric device, wherein the battery comprises a heat absorption assembly and a battery cell group existing on at least one side of the heat absorption assembly; the battery cell group comprises battery cells; the heat absorption assembly comprises a shell and a heat absorption composite material in a cavity surrounded by the shell, the heat absorption composite material comprises a support layer and a heat absorption material arranged on the support layer; the heat absorption material comprises a phase change material; and the support layer comprises at least one support unit arranged in a first direction of the heat absorption composite material in a laminated mode; the first direction is the arrangement direction of the heat absorption assembly and the battery cell group existing on at least one side of the heat absorption assembly. By reasonably controlling the related physical properties of the heat absorption assembly and the battery cells in the battery, the battery can have good thermal safety protection capability when the battery meets the formula range of the constraints of the application.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery, a battery pack, and an electrical device. Background Technology

[0002] Battery thermal runaway typically occurs when the heat generated by internal chemical reactions exceeds the battery's heat dissipation capacity, causing a rapid temperature rise and triggering a chain reaction that can ultimately lead to fire or explosion. This phenomenon can be caused by a variety of factors, including overcharging / discharging, short circuits, high external temperatures, or manufacturing defects. Effective thermal management is crucial for preventing thermal runaway; it not only ensures the battery operates within a safe temperature range but also optimizes its performance and extends its lifespan. Thermal management systems control battery temperature, reduce aging rates, improve charge / discharge efficiency, and ensure battery reliability and safety under various operating conditions.

[0003] To address battery thermal runaway, the primary current solution is to employ highly efficient thermal insulation materials, such as aerogels, to block the heat conduction path between battery cells. These materials possess high thermal stability and extremely low thermal conductivity, maintaining structural integrity and functional effectiveness under extreme temperature conditions, thus significantly suppressing heat transfer from the runaway cell to surrounding cells. However, while these insulation materials effectively prevent high-temperature conduction, they only delay, not completely prevent, heat diffusion between cells. Once a cell experiences thermal runaway, the generated heat can still gradually affect adjacent cells, eventually leading to a chain reaction and multi-cell thermal runaway. Summary of the Invention

[0004] This invention provides a battery in which the internal heat-absorbing component has the ability to absorb heat quickly and can block the transfer of heat between the battery cells. The battery has good thermal safety protection capabilities, can stably provide power to external electrical devices, and has a long service life.

[0005] The present invention provides a battery pack including the above-mentioned battery, which has good thermal safety protection capability.

[0006] The present invention provides an electrical device including the battery as described above. The battery of the electrical device has good thermal safety protection capabilities and high stability and safety during operation.

[0007] A first aspect of the present invention provides a battery, wherein the battery includes a heat-absorbing component and a cell assembly present on at least one side of the heat-absorbing component;

[0008] The battery pack includes battery cells;

[0009] The heat-absorbing assembly includes a housing and a heat-absorbing composite material located in a cavity enclosed by the housing, the heat-absorbing composite material including a support layer and a heat-absorbing material disposed on the support layer;

[0010] The heat-absorbing material includes a phase change material;

[0011] The support layer includes at least one support unit stacked along a first direction of the heat-absorbing composite material;

[0012] The first direction is the arrangement direction of the heat-absorbing component and the battery cell group present on at least one side of the heat-absorbing component;

[0013] The battery satisfies:

[0014] and,

[0015]

[0016] Wherein, r is the mass content of the phase change material in the heat-absorbing material, expressed in %;

[0017] ρ is the density of the heat-absorbing material, in kg / m³. 3 count;

[0018] S is the area of ​​the heat-absorbing composite material projected onto a plane perpendicular to the first direction, in mm. 2 count;

[0019] x1 is the dimension of the cavity in the first direction, in mm;

[0020] a is the ratio of the area of ​​the support layer projected onto a plane perpendicular to the first direction to S;

[0021] n1 is the number of layers in the support unit;

[0022] x2 is the dimension of a single-layer support unit in the first direction, in mm;

[0023] Qc is the rated energy of the battery cell, expressed in kJ.

[0024] n2 is the number of battery cells in the battery cell group, where n2 ≥ 2 and n2 is an integer;

[0025] C p The specific heat capacity of the battery cell is expressed in kJ / (kg·K).

[0026] m represents the mass of a single battery cell, expressed in kg.

[0027] The battery described above, wherein the battery satisfies:

[0028]

[0029] And / or,

[0030] The battery described above, wherein the battery satisfies:

[0031] x1-n1x2≤16.

[0032] The battery described above, wherein the battery satisfies:

[0033]

[0034] The battery described above, wherein the battery satisfies:

[0035]

[0036] The battery described above, wherein the battery satisfies:

[0037]

[0038] In the battery described above, the percentage of r is 80-99%;

[0039] And / or, the ρ is 900–1200 kg / m³ 3 ;

[0040] And / or, S is 8000~600000mm 2 ;

[0041] And / or, the x1 is 8 to 30 mm;

[0042] And / or, the percentage of a is 10% to 50%;

[0043] And / or, n1*x2 is 3 to 30 mm;

[0044] And / or, the Qc is 576–7200 kJ;

[0045] And / or, n2 is 3 to 30;

[0046] And / or, the C p It ranges from 0.8 to 1.2 kJ / (kg·K).

[0047] And / or, the m is 1 to 4 kg.

[0048] In the battery described above, the first direction is the thickness direction of the heat-absorbing component.

[0049] In the battery described above, the heat-absorbing component is disposed between at least two adjacent cell groups.

[0050] In the battery described above, the heat-absorbing component is provided between each pair of adjacent groups of the battery cells.

[0051] In the battery described above, the support layer includes pores, and at least a portion of the pores of the support layer is filled with the heat-absorbing material.

[0052] In the battery described above, at least a portion of the heat-absorbing material is also disposed on opposite sides of the support layer in the first direction;

[0053] And / or, the support layer comprises at least two layers of the support units stacked along the first direction of the heat-absorbing composite material.

[0054] The battery as described above, wherein the casing includes a casing body and a cover plate,

[0055] The cover plate is used to close the shell body to enclose and form a cavity;

[0056] And / or, at least one of the structures of the cover plate and the shell body is provided with an explosion-proof valve.

[0057] The battery as described above, wherein the casing body comprises at least one of aluminum, steel, and aluminum-plastic film;

[0058] And / or, the cover plate includes at least one of aluminum, steel, and aluminum-plastic film.

[0059] In the battery described above, the support layer comprises at least one of aluminum, steel, ceramic, and glass fiber;

[0060] And / or, the heat-absorbing material includes at least one of hydrogel, hydrated salt, and colloid.

[0061] The battery as described above, wherein the battery cell includes at least one of a lithium-ion battery and a sodium-ion battery;

[0062] Preferably, the lithium-ion battery includes a positive electrode active material, which includes one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, and lithium nickel oxide.

[0063] As described above, the battery cell includes a negative electrode active material, which includes one or more of carbon-based, silicon-based, and titanium-based negative electrode active materials.

[0064] Preferably, the carbon-based anode active material includes one or more of graphite, hard carbon, and soft carbon; the silicon-based anode active material includes one or more of silicon-carbon materials, silicon-oxygen materials, and elemental silicon; and the titanium-based anode active material includes lithium titanate.

[0065] The battery described above is a liquid battery, a semi-solid battery, or a solid battery.

[0066] In another aspect, the present invention provides a battery pack comprising a housing and a battery as described above, the battery being located within the housing.

[0067] In another aspect, the present invention provides an electrical device, wherein the electrical device includes a battery as described above or a battery pack as described above.

[0068] The battery provided by the present invention controls the physical parameters of the heat-absorbing component and the cell assembly, so that the heat-absorbing component exhibits good thermal safety protection capability during the thermal runaway of the battery and prevents the battery from thermal diffusion. Attached Figure Description

[0069] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0070] Figure 1A A schematic diagram of a battery provided according to an embodiment of the present invention;

[0071] Figure 1B A schematic diagram of a battery provided according to an embodiment of the present invention;

[0072] Figure 2 This is a schematic diagram of a heat-absorbing component provided in an embodiment of the present invention;

[0073] Figure 3 This is a cross-sectional schematic diagram of the heat-absorbing composite material provided in an embodiment of the present invention in the thickness direction;

[0074] Figure 4 This is a cross-sectional view of a heat-absorbing component in the thickness direction according to an embodiment of the present invention;

[0075] Figure 5 A schematic diagram of the support layer provided in another embodiment of the present invention;

[0076] Figure 6 A schematic diagram of the support layer provided in another embodiment of the present invention;

[0077] Figure 7 This is a schematic diagram of a double-layer support layer provided in another embodiment of the present invention;

[0078] Figure 8This is a schematic diagram of a heat-absorbing component provided in an embodiment of the present invention;

[0079] Figure 9 This is a top view of the needle puncture test device of the present invention;

[0080] Figure 10 This is a schematic diagram of a battery pack tray provided in an embodiment of the present invention.

[0081] Explanation of reference numerals in the attached figures:

[0082] 1: Heat-absorbing components;

[0083] 11: Heat-absorbing composite materials;

[0084] 111: Support layer;

[0085] 112: Heat-absorbing material;

[0086] 12: Shell;

[0087] 121: Shell body;

[0088] 122: Cover plate;

[0089] 1221: convex platform;

[0090] 1222: Explosion-proof valve;

[0091] 2: Battery cell assembly;

[0092] 21: Battery cell;

[0093] 22: Cold-rolled steel plate, cold-rolled metal plate.

[0094] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0095] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0096] During battery operation, prolonged operation and external mechanical damage can trigger thermal runaway within the battery cell, transferring heat to adjacent cells and ultimately leading to battery fire or explosion, posing a significant safety hazard. Applying thermal insulation material to the surface of the battery cell can effectively address this issue. However, thermal insulation material can only block heat transfer; that is, it can only slow down, not prevent, heat propagation. Therefore, the thermal management effect of thermal insulation material is limited.

[0097] Therefore, there is an urgent need for a battery that can effectively protect the battery's thermal safety by incorporating heat-absorbing components in conjunction with other battery components.

[0098] Based on this, the first aspect of the present invention provides a battery, the battery including a heat-absorbing component and a cell assembly present on at least one side of the heat-absorbing component;

[0099] A battery pack includes battery cells;

[0100] The heat-absorbing component includes a housing and a heat-absorbing composite material located in a cavity enclosed by the housing. The heat-absorbing composite material includes a support layer and a heat-absorbing material disposed in the support layer.

[0101] The heat-absorbing material includes a phase change material; the support layer includes at least one support unit stacked along a first direction of the heat-absorbing composite material;

[0102] The first direction is the arrangement direction of the heat-absorbing component and the battery cell group present on at least one side of the heat-absorbing component;

[0103] The battery meets the following requirements:

[0104] and,

[0105]

[0106] Where r is the mass content of phase change material in the heat-absorbing material, expressed in %;

[0107] ρ is the density of the heat-absorbing material, expressed in kg / m³. 3 count;

[0108] S is the area of ​​the heat-absorbing composite material projected onto a plane perpendicular to the first direction, in mm. 2 count;

[0109] x1 is the dimension of the cavity in the first direction, in mm;

[0110] 'a' is the ratio of the area of ​​the support layer's orthographic projection onto a plane perpendicular to the first direction to S.

[0111] n1 is the number of layers in the support unit;

[0112] x2 is the dimension of a single-layer support unit in the first direction, in mm;

[0113] Qc is the rated energy of the battery cell, expressed in kJ.

[0114] n2 is the number of cells in the cell group, n2≥2 and n2 is an integer;

[0115] C p This refers to the specific heat capacity of the battery cell, expressed in kJ / (kg·K).

[0116] m represents the mass of a single battery cell, expressed in kg.

[0117] The battery provided by this invention controls the physical parameters of the heat-absorbing component and the cell assembly to ensure that the physical parameters of the heat-absorbing component and the cell assembly satisfy the above-mentioned relationship. This effectively ensures that the heat generated by the cell that experiences thermal runaway in the cell assembly can be largely absorbed by the heat-absorbing component, thereby effectively reducing the heat diffusion to the adjacent cell assembly and avoiding thermal runaway of the adjacent cell assembly. This prevents the battery from experiencing thermal diffusion problems and improves the overall safety of the battery.

[0118] It should be noted that the above parameters are calculated by substituting the values ​​of the above "units are XX" into formulas 1 and 2.

[0119] In detail, the battery includes a heat-absorbing component and a cell assembly present on at least one side of the heat-absorbing component; the cell assembly includes a cell; the heat-absorbing component includes a housing and a heat-absorbing composite material located in a cavity enclosed by the housing, the heat-absorbing composite material includes a support layer and a heat-absorbing material disposed on the support layer; the heat-absorbing material includes a phase change material; the support layer includes at least one support unit stacked along a first direction of the heat-absorbing composite material; the first direction is the arrangement direction of the heat-absorbing component and the cell assembly present on at least one side of the heat-absorbing component.

[0120] In this embodiment of the invention, "multiple" can be understood as two or more.

[0121] The embodiments of the present invention do not impose any special limitation on the size of the battery cell. For example, the size of the battery cell can be (200-1900mm)*(20-300mm)*(13-20mm), such as (200-1890mm)*(25-300mm)*(13-20mm). Exemplarily, the size of the battery cell can be 960mm*90mm*13.5mm, 1890*300*19.5mm, or 200*25*13.5mm.

[0122] Specifically, such as Figure 1AIn one specific embodiment shown, the battery includes at least one set of battery cells 2 and heat-absorbing components 1 located on both sides of each set of battery cells 2. For example, the battery may include two sets of battery cells and one heat-absorbing component, with the heat-absorbing component located between the two sets of battery cells. The battery may also include more than one heat-absorbing component, with a battery cell set disposed between any two heat-absorbing components. A battery may include three sets of battery cells 2 and two heat-absorbing components 1, with the battery cell set 2 disposed between the two heat-absorbing components 1. By distributing the heat-absorbing component between each pair of adjacent sets of battery cells, the present invention enables the battery assembled from the battery cells and heat-absorbing components to have good thermal safety protection capabilities.

[0123] In the aforementioned battery, each cell group independently comprises one or more cells 21. By assembling one or more cells into a cell group, it is beneficial to further improve the energy density of the battery.

[0124] like Figure 2 As shown, the heat-absorbing component 1 provided by the present invention includes two surfaces S' and S' with the largest area in the thickness direction (i.e., the first direction).

[0125] like Figure 3 and Figure 4 As shown, the heat-absorbing component 1 of the present invention includes a heat-absorbing composite material 11 and a shell 12 disposed on the outside of the heat-absorbing composite material 11. The heat-absorbing composite material 11 includes a support layer 111 and a heat-absorbing material 122 disposed on the support layer.

[0126] Heat-absorbing materials include phase change materials (PCMs), which are used to absorb the heat generated during thermal runaway of the battery cell. Generally, PCMs can be water or ethanol, among other options.

[0127] It should be noted that, in one embodiment of the present invention, the heat-absorbing material is a solid or liquid phase change material, such as paraffin, water, ethanol, isopropanol, n-heptane, inorganic salt solution, etc. In another embodiment of the present invention, the heat-absorbing material is at least one of hydrogel, hydrated salt, and colloid. For example, the heat-absorbing material includes one or more of polyacrylamide hydrogel, sodium polyacrylate hydrogel, polyvinyl alcohol hydrogel, poly(N-isopropylacrylamide) hydrogel, calcium chloride hexahydrate, sodium sulfate decahydrate, potassium nitrate trihydrate, silica sol, and gelatin colloid. The above-mentioned heat-absorbing material includes a matrix and a phase change material. The matrix is ​​used to bind the phase change material, absorb heat after heating, and cause the phase change material to detach from the matrix. The phase change material is one or more of water, ethanol, isopropanol, n-heptane, inorganic salt solution, etc.

[0128] like Figure 4 As shown, the heat-absorbing component 1 includes a housing and a heat-absorbing composite material 11 located in a cavity enclosed by the housing.

[0129] like Figure 5, Figure 6 , Figure 7 As shown, the support layer 111 includes at least one support unit stacked along the first direction of the heat-absorbing composite material 11.

[0130] The first direction is the arrangement direction of the heat-absorbing component and the battery cell group located on at least one side of the heat-absorbing component.

[0131] In detail, in this embodiment of the invention, r represents the mass content of the phase change material in the endothermic material, expressed as a percentage. The mass content of the phase change material in the endothermic material is measured by thermogravimetric analysis (TGA). Specifically, this involves monitoring changes in sample mass to detect reactions such as material thermal properties, degradation, and water loss, thereby inferring the mass content of the phase change material. This includes the following steps:

[0132] 1) Sample preparation: Prepare a sample of the above-mentioned heat-absorbing material and record the initial mass of the sample.

[0133] 2) Sample placement: Place the heat-absorbing material sample evenly on the sample stage, and try to keep the sample uniform.

[0134] 3) Set the temperature range: Set the temperature range in the TGA instrument and heat the sample according to the set temperature.

[0135] 4) Monitoring mass changes: During the thermal decomposition of the sample, the TGA instrument continuously records the mass change curve of the sample. When the phase change material in the sample begins to volatilize, the total mass of the sample will change.

[0136] 5) Calculate the mass content of phase change material: By analyzing and calculating the thermal analysis curve, the mass content of phase change material can be obtained. The mass content of phase change material is the mass percentage of phase change material in the heat-absorbing material.

[0137] Specifically, the TGA test parameters are:

[0138] Atmosphere: Ar; Rate: 50.0 mL / min; Heating rate: 10℃ / min; Calculation temperature range for water content: 20-150℃.

[0139] ρ is the density of the heat-absorbing material, expressed in kg / m³. 3 The density of the heat-absorbing material is measured using a densitometer, specifically including the following steps:

[0140] Place the sample (a preset mass of heat-absorbing material) into the densitometer, wait a few seconds for the sample to stabilize, and then read the value displayed on the densitometer. The density of the heat-absorbing material mentioned above refers to the density of the heat-absorbing material on any side of the thickness direction of the heat-absorbing component or inside the pores of the support layer.

[0141] like Figure 2As shown, S is the area of ​​the heat-absorbing composite material projected onto a plane perpendicular to the first direction, in mm. 2 The area is calculated using a suitable formula based on the shape of the surface when the surface is a regular shape. For example, the area of ​​a rectangle is the length multiplied by its width. If the surface is irregular, laser scanning can be used to accurately measure the three-dimensional data using lidar technology, and then the area can be calculated using a computer. In this invention, the surface areas of opposite sides of the heat-absorbing composite material are the same in its thickness direction. Furthermore, if the surface of the heat-absorbing composite material 11 is uneven on either side in the thickness direction, S is taken as the area of ​​the orthographic projection of the heat-absorbing composite material onto a plane perpendicular to the first direction.

[0142] In some embodiments of the present invention, the area of ​​the orthographic projection of the battery cell onto a plane perpendicular to the first direction can be equal to, less than, or greater than the aforementioned S. The area of ​​the orthographic projection of the battery cell onto the plane perpendicular to the first direction can be measured in the same manner as S, and will not be elaborated here.

[0143] like Figure 4 As shown, x1 is the dimension in the first direction, in mm. The dimension x1 of the cavity in the first direction is measured using a vernier caliper and a laser rangefinder.

[0144] 'a' represents the ratio of the area of ​​the orthographic projection of the support layer 111 onto the plane perpendicular to the first direction to S. Specifically, the support layer 111 contains both pores and non-pore solid areas. The solid areas of the support layer will project onto the plane perpendicular to the first direction of the heat-absorbing composite material 11, while the pores will not. Specifically, the area of ​​the orthographic projection of the support layer 111 onto the plane perpendicular to the first direction can be calculated using the laser scanning method described above. The area of ​​the orthographic projection of the support layer 111 onto the plane perpendicular to the first direction is then divided by S to obtain 'a'. In one embodiment, a cross-section of the support layer can be made, and the area of ​​the pores can be measured. Based on S and the pore area, the ratio of the area of ​​the orthographic projection of the support layer 111 onto the plane perpendicular to the first direction to S can be obtained.

[0145] n1 represents the number of layers in the support unit. For example, the support unit can be one layer, or it can be two or more layers.

[0146] In this invention, the rated energy, specific heat capacity, and other characteristics of the battery cell can be controlled and tested using conventional methods in the field.

[0147] like Figure 4As shown in the figure, the support unit is a single layer, and x2 is the dimension of the single-layer support unit in the first direction, in mm. The dimension x2 of the single-layer support unit in the first direction is measured using a vernier caliper and a laser rangefinder. When the thickness of the single-layer support unit in the first direction is not uniform, x2 can be understood as the average dimension of the single-layer support unit in the first direction (in...). Figure 1A , 1B , Figure 4 In the embodiment shown, the average dimension of a single-layer support unit in the first direction is the average thickness of the single-layer support unit.

[0148] Qc is the rated energy of the battery cell, expressed in kJ. The rated capacity of the battery cell is obtained through battery load testing, which includes the following steps:

[0149] 1) At room temperature, charge with a small current to the cutoff voltage and let stand for 1 hour;

[0150] 2) Discharge to the cutoff voltage with a constant current of 1 / 3C, and let stand for 1 hour;

[0151] Repeat steps 1-2 twice in total. Record the second discharge capacity as the battery capacity. Then determine the rated energy of the cell using the following method.

[0152] Method for determining the rated energy of a battery cell: The rated energy Qc of a battery cell can be converted from the cell capacity C. The conversion relationship is: Rated energy Qc (Wh) = Cell capacity C (Ah) × Cell voltage (V). Then, the rated energy (Wh) of the battery cell is converted into the rated energy Qc of the battery cell in this embodiment of the invention according to 1Wh = 3.6kJ.

[0153] In some embodiments, the capacity C of a single cell can be from 50Ah to 300Ah, for example, a range of 50Ah, 100Ah, 150Ah, 200Ah, 250Ah, 300Ah or any combination thereof.

[0154] Generally, the low current is between 1 / 5C and 1 / 2C. In this embodiment, a lithium iron phosphate battery (lithium iron phosphate system battery) is used, therefore the cutoff voltage is 3.75V. In some embodiments, lithium manganese iron phosphate (lithium manganese iron phosphate system battery) batteries and ternary lithium batteries (ternary cathode system batteries) can also be used. The cutoff voltage of the lithium manganese iron phosphate battery is between 3.8V and 4.2V, specifically determined based on the manganese content; the cutoff voltage of the ternary lithium battery is 4.2V or 4.35V, which can be selected based on the specific composition of the ternary lithium battery.

[0155] Furthermore, in this embodiment of the invention, when the battery has two or more cell groups, the Qc of the cells in the cell groups on both sides of the heat-absorbing component along the first direction may be the same or different. However, when the Qc of any cell group on both sides of the heat-absorbing component along the first direction is substituted into any of the above formulas for calculation, both the heat-absorbing component and any cell group on both sides of the heat-absorbing component along the first direction satisfy the conditions defined by the above formulas. In addition, in other embodiments, the average Qc of the cell group can also be substituted into the above formulas for calculation.

[0156] n2 represents the number of cells in the cell group, where n2 ≥ 2 and n2 is an integer. Specifically, each cell group can contain multiple cells. In this embodiment of the invention, when the battery has two or more cell groups, the number of cells in the cell groups on both sides of the heat-absorbing component along the first direction can be the same or different. However, when the number of cells in any one of the cell groups on both sides of the heat-absorbing component along the first direction is substituted into any of the above formulas for calculation, both the heat-absorbing component and any one of the cell groups on both sides of the heat-absorbing component along the first direction satisfy the conditions defined by the above formulas. In specific implementation, the cell group with the largest number of cells can be substituted into the above formulas for calculation.

[0157] C p The specific heat capacity of the battery cell is expressed in kJ / (kg·K). It is calculated using differential scanning calorimetry (DSC). DSC is a technique for measuring the change of a substance's physical properties with temperature under programmed temperature control. The enthalpy change of the endothermic material is measured using the measurement method described in the instruction manual for DSC measurement. In some embodiments, the battery contains multiple cell groups. The specific heat capacities of the cells in a cell group may be the same or different. However, when calculating using the specific heat capacity of any cell group on either side of the endothermic component along the first direction, both the endothermic component and any cell group on either side of the endothermic component along the first direction must satisfy the above formula requirements. In specific implementation, the average specific heat capacity of all cells in the battery can be used for calculation.

[0158] Specifically, the specific heat capacity is obtained by monitoring the heat absorbed or released when the cell temperature changes, including the following steps:

[0159] The battery cell (which is functioning normally and has not experienced thermal runaway) is weighed to obtain its mass as m1. A heating element (smaller than the battery cell, which can be clamped) is fixed between the large surfaces of the two battery cells and placed in an insulated environment at a temperature of 25–35℃ (±3℃). The heating power is adjusted to raise the temperature of the battery cell from 25℃ (±3℃) to 35℃ (±3℃) with a constant heating power P, while keeping the heating rate constant within the range of 0.2–0.3℃ / min. Thermocouples are arranged on the large surfaces of the battery cell (the two surfaces perpendicular to the first direction) to obtain the actual temperature rise rate dT / dt of the battery cell during the heating process, based on ΔQ=C p ×m1×ΔT=P×Δt, and ΔT / Δt=dT / dt, then through C p =P / [m1×(dT / dt)] gives C p The specific value.

[0160] m represents the mass of a single battery cell, expressed in kg. Specifically, it is obtained by weighing the battery cell using a balance at room temperature.

[0161] It should be clarified that, in order to enable normal battery assembly, the present invention also limits 0 ≤ x1 - n1x2. When the battery meets the above requirements, the heat-absorbing composite material can be assembled into the casing to form a complete battery.

[0162] This invention achieves the following by making the battery meet the requirements: as well as When the battery meets these requirements, the heat generated by a cell experiencing thermal runaway can be effectively absorbed by the heat-absorbing component, thereby reducing heat diffusion to adjacent cell groups and preventing thermal runaway in those groups, thus improving overall battery safety. Furthermore, meeting these requirements optimizes the internal heat distribution and conduction paths, reduces the formation of localized hot spots, extends battery life, and improves charge / discharge efficiency.

[0163] Furthermore, in one specific embodiment, the battery also satisfies:

[0164]

[0165] When a battery satisfies the above formula, it can maintain good thermal management while ensuring a small volume ratio of heat-absorbing components. This allows a larger number of cells to be contained within a given battery volume, ensuring high volumetric energy density, space utilization, and output capacity. Furthermore, it simplifies the complexity of the thermal management system, reduces system weight and cost, and promotes the development of battery systems towards lightweight and high energy density.

[0166] In one specific implementation, the battery also satisfies:

[0167]

[0168] When the battery meets the above formula, it can maintain good thermal management while ensuring that the volume of the heat-absorbing component is small. This allows a large number of cells to be contained in a battery of a certain volume, ensuring that the battery has high volumetric energy density, space utilization and output power.

[0169] In one specific embodiment, the present invention further defines the aforementioned parameters of the support layer and the battery cell. As described above, the battery satisfies:

[0170] 0≤x1-n1x2≤16.

[0171] Under the above conditions, the heat absorption component can ensure that the heat absorption requirements are met while also being able to adapt to the expansion force generated when the battery is working, thereby reducing the risk of material being squeezed out of the heat absorption component.

[0172] Considering battery energy density, the battery in this embodiment of the invention satisfies the following:

[0173]

[0174] When the battery meets the above conditions, even with the addition of heat-absorbing components, the battery can maintain a higher energy density.

[0175] In one specific embodiment, since the heat-absorbing material inside needs to resist the pressure generated by the expansion of the battery, the above-mentioned battery satisfies:

[0176]

[0177] When the battery parameters meet the above range, the support layer has good mechanical properties, which can reduce the risk of battery runaway when the cell expansion force increases. The inventors discovered through research that by disassembling the heat-absorbing component after operation that meets the above formula, the support layer of the heat-absorbing component is relatively intact and not easily deformed or broken.

[0178] Furthermore, in one specific embodiment, the battery also satisfies:

[0179]

[0180] In detail, when the parameters in the battery meet the above range, the risk of the heat-absorbing component being squeezed out during battery expansion can be reduced, thereby improving the battery's thermal safety protection capability. Disassembling the heat-absorbing component that meets the above formula reveals that its encapsulation is relatively complete, which is beneficial to improving the battery's safety and reliability.

[0181] To further improve the heat absorption performance of the heat-absorbing material, this invention further limits the mass content (r) of the phase change material in the heat-absorbing material to 80-99%. For example, r includes, but is not limited to, 80%, 85%, 90%, 95%, 99%, or any combination thereof. When the mass content of the phase change material in the heat-absorbing material is within the above range, the thermal stability and mechanical strength of the heat-absorbing material can be effectively improved, ensuring its long-term reliability under high temperature and dynamic heat load conditions. This not only improves the battery's working efficiency and charge / discharge performance but also extends its service life.

[0182] Considering battery energy density and thermal management performance, in one specific embodiment, the present invention further specifies that the density ρ of the heat-absorbing material is 900–1200 kg / m³. 3 For example, ρ includes, but is not limited to, 900 kg / m³. 3 1000kg / m 3 1100kg / m 3 1200kg / m 3 Or a range consisting of any two of these. By adjusting the density of the heat-absorbing material, the energy storage capacity of the battery system can be maximized while ensuring efficient thermal management. Furthermore, controlling the density of the heat-absorbing material within the aforementioned range can improve the compatibility between the material and the battery, ensure stable operation over long periods, reduce the risk of thermal runaway, and enhance battery safety.

[0183] In one specific embodiment, S is 8000–600000 mm. 2 For example, S includes, but is not limited to, 8000mm 2 10000mm 2 50000mm 2 100000mm 2 200000mm 2 300000mm 2 600000mm 2 Or a range consisting of any two of these. This invention, by controlling the area of ​​the heat-absorbing composite material's orthogonal projection onto a plane perpendicular to the first direction within the aforementioned range, helps to further reduce the risk of thermal runaway in the battery.

[0184] Furthermore, in the aforementioned heat-absorbing component, x1 ranges from 8 to 30 mm. For example, x1 includes, but is not limited to, a range of 8 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, or any combination thereof. By controlling the dimensions of the cavity of the heat-absorbing component within the aforementioned range in the first direction, this invention helps to balance the heat insulation effect and heat dissipation requirements. This not only prevents the influence of external ambient temperature on the internal battery cells during battery operation but also ensures that the generated heat is dissipated in a timely manner, avoiding the formation of localized overheating points, thereby maintaining the battery operation within a safe and stable temperature range.

[0185] During battery operation, in order to ensure that the support layer 111 has adequate space to accommodate battery deformation under stress, in one specific embodiment, the area of ​​the support layer 111 projected onto a plane perpendicular to the first direction accounts for 10% to 50% of S. For example, a includes, but is not limited to, 5%, 15%, 25%, 35%, 45%, 50%, or any combination thereof.

[0186] The present invention further limits the total thickness n1*x2 of the support layer to 3 to 30 mm. For example, n1*x2 includes, but is not limited to, 3 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm, which can provide good support for the heat-absorbing material and enable the heat-absorbing component to have a good heat absorption effect.

[0187] Based on considerations of battery energy density, this invention further limits the rated energy Qc of the battery cell to 576–7200 kJ. For example, Qc includes, but is not limited to, a range of 576 kJ, 600 kJ, 1000 kJ, 1500 kJ, 2000 kJ, 2500 kJ, 3000 kJ, 3456 kJ, 500 kJ, 600 kJ, 7000 kJ, 7200 kJ, or any combination thereof. When the rated energy Qc of the battery cell is within the above range, it can ensure that the battery cell maintains stable performance output throughout the entire operating temperature range, reducing efficiency degradation and capacity loss caused by temperature fluctuations.

[0188] In one specific embodiment, each of the above-mentioned cell groups independently includes 3 to 30 cells. For example, the number of cells n2 includes, but is not limited to, 3, 5, 10, 15, 20, 25, 30, or any combination thereof. By further limiting the number of cells in the cell group, the present invention is beneficial to further improve the volumetric energy density and safety of the battery.

[0189] In one specific embodiment, the present invention further controls the mass m of a single cell to be 1 to 4 kg. For example, m includes, but is not limited to, a range of 1 kg, 2 kg, 3 kg, 4 kg or any two of them. Limiting the mass of a single cell is beneficial to improving the energy density and thermal management performance of the battery.

[0190] In this embodiment of the invention, the first direction is the thickness direction of the heat-absorbing component. Specifically, the length and width of the heat-absorbing component are greater than its thickness, in which case the heat-absorbing component is a regular hexahedron.

[0191] In some embodiments, a heat-absorbing component is provided between at least two adjacent battery cell groups.

[0192] In this embodiment of the invention, a heat-absorbing component is provided between each pair of adjacent battery cell groups. Specifically, the heat-absorbing component can be arranged between the large surfaces of the battery cell (i.e., the large surfaces are the two surfaces of the battery cell perpendicular to the first direction). The large surfaces of the battery cell are perpendicular to the first direction, and both surfaces of the battery cell in the first direction are large surfaces. For example, when the battery cell is a regular cuboid, the large surface of the battery cell is the surface enclosed by the long side and the wide side of the battery cell, and the length and width of the battery cell are greater than its thickness.

[0193] For example, such as Figure 1A As shown, the battery includes three cell groups 2 and two heat-absorbing components 1, with the cell groups 2 positioned between the two heat-absorbing components. By placing the heat-absorbing components between each pair of adjacent cell groups, this invention enables the battery assembled from the cell groups and heat-absorbing components to have excellent thermal safety protection capabilities.

[0194] In some embodiments, at least a portion of the heat-absorbing material is disposed between the support layer and the housing to improve the heat absorption capacity of the heat-absorbing assembly.

[0195] In some embodiments, the support layer 111 includes pores, and at least a portion of the pores of the support layer 111 is filled with a heat-absorbing material 112. The pores in the support layer can be either through-holes or non-through-holes, as long as they can accommodate the heat-absorbing material. It is understood that when there is excessive heat-absorbing material within the pores of the support layer, the heat-absorbing material can also be disposed on both sides of the support layer in the first direction.

[0196] In some embodiments, the support layer 111 includes pores, at least a portion of which is filled with a heat-absorbing material 122. The pores in the support layer can be either through-holes or non-through-holes, as long as they can accommodate the heat-absorbing material. It is understood that when there is excessive heat-absorbing material within the pores of the support layer, the heat-absorbing material can also be disposed on opposite sides of the support layer in the first direction.

[0197] Considering the heat absorption efficiency of the heat-absorbing component, the support layer of the present invention includes pores, and at least a portion of the pores of the support layer 111 are filled with a heat-absorbing material 112. For example... Figure 5 and Figure 6 As shown, the shapes of the holes include hexagons and squares.

[0198] In the heat-absorbing component 1 of this embodiment, at least a portion of the heat-absorbing material is also disposed on opposite sides of the support layer in the first direction. It should be noted that at least a portion of the heat-absorbing material can be disposed on either one side of the support layer in the first direction or on opposite sides of the support layer in the first direction.

[0199] In some embodiments, a portion of the heat-absorbing material fills at least a portion of the pores in the support layer, and the remaining components are distributed on opposite sides of the support layer in a first direction (thickness direction).

[0200] In detail, in some embodiments, at least a portion of the heat-absorbing material 112 may fill some of the pores in the support layer 111, or it may fill all the pores in the support layer 111. By setting the pores of the support layer 111 to square or hexagonal shapes, the present invention improves the mechanical properties of the support layer 111. Furthermore, the pores in the support layer 111 can accommodate additional heat-absorbing material 112, which improves the heat absorption performance of the heat-absorbing assembly.

[0201] To accommodate the mechanical performance requirements of different batteries, in this invention, the support layer 111 comprises at least two layers of support units stacked along the thickness direction of the heat-absorbing composite material 11, so as to... Figure 7 For example, the support layer 111 includes two support units, which are stacked along the first direction of the heat-absorbing composite material 11.

[0202] In some embodiments, such as Figure 8 As shown, the housing 12 includes a housing body 121 and a cover plate 122; the cover plate 122 is used to close the housing body 121 to enclose and form a cavity, and the heat-absorbing composite material 111 is located in the cavity. In some embodiments, the cover plate 122 is disposed at one or both ends of the housing body 121 along its length.

[0203] like Figure 8 As shown, the outer shell includes a shell body surrounding the heat-absorbing composite material. Specifically, the shell body surrounds two surfaces perpendicular to the thickness direction (first direction) of the heat-absorbing composite material and two surfaces perpendicular to the width direction of the heat-absorbing composite material; the two surfaces perpendicular to the first direction of the heat-absorbing composite material are in contact with the battery cell.

[0204] Specifically, at least one of the structures, namely the cover plate and the shell body, is equipped with an explosion-proof valve. For example, such as Figure 8As shown, the cover plate 122 also includes a boss 1221 and an explosion-proof valve 1222. The boss 1221 is used for assembling battery packs in the industrial chain, and the explosion-proof valve 1222 is used to control the internal pressure of the heat-absorbing component and improve battery safety. This invention encapsulates the heat-absorbing composite material by using a cover plate and a shell, which is beneficial for preparing heat-absorbing components with high heat-absorbing performance.

[0205] In some embodiments, such as Figure 1B As shown, the battery also includes a cold plate, which is located on at least one side of the cell assembly in a second direction (i.e., the cold plate is positioned above and / or below the cell assembly). The second direction intersects the first direction, and may be perpendicular to each other. The cold plate provides a cooling effect, further improving the battery's safety performance. Specifically, the first direction may be parallel to the battery's thickness direction, and the cold plate may be positioned on at least one side of the battery's thickness direction. Specifically, at least one surface of the battery's thickness direction may be provided with a cold plate 22. This can be provided on one side of the battery's thickness direction, or on opposite sides of the battery's thickness direction.

[0206] Specifically, the cold plate 22 may include a metal cold plate 22, that is, the cold plate 22 is made of metal.

[0207] Specifically, the cold plate 22 and the battery can be bonded together using adhesive materials such as structural adhesive. For example, the metal cold plate 22 and the battery can be bonded together using structural adhesive to further improve the battery's thermal safety protection capability.

[0208] As mentioned above, in the above heat-absorbing components, the shell body includes at least one of aluminum, steel, and aluminum-plastic film.

[0209] In one specific embodiment, the cover plate includes at least one of aluminum, steel, and aluminum-plastic film.

[0210] By using the above-mentioned materials as the shell body and cover plate, the present invention can improve the thermal conductivity of the heat-absorbing components and enhance the thermal safety protection capability of the battery.

[0211] Considering the mechanical properties of the support layer, in one specific embodiment, the support layer in the heat-absorbing component of the present invention includes at least one of aluminum, steel, ceramic, and glass fiber. Further, in some embodiments, the support layer can be a honeycomb structure.

[0212] In one specific embodiment, the heat-absorbing material includes at least one of hydrogels, hydrated salts, and colloids. For example, the heat-absorbing material includes one or more of polyacrylamide hydrogel, sodium polyacrylate hydrogel, polyvinyl alcohol hydrogel, poly(N-isopropylacrylamide) hydrogel, calcium chloride hexahydrate, sodium sulfate decahydrate, potassium nitrate trihydrate, silica sol, and gelatin colloid. The above materials include a matrix and a phase change material, where the phase change material is one or more of water, ethanol, isopropanol, n-heptane, and inorganic salt solutions. These substances have rapid phase change reaction rates, can respond quickly to temperature changes, and absorb or release heat promptly. Furthermore, the physicochemical properties of these substances are relatively stable, not easily decomposed or degraded, and can maintain their performance for a relatively long time, thereby improving the thermal management performance of the battery.

[0213] Generally, a battery cell includes a positive electrode, a negative electrode, and a separator between the positive and negative electrode. The positive electrode includes a positive current collector and a positive active layer disposed on at least one side of the positive current collector. The positive active layer includes positive active materials, conductive agents, and binders. The negative electrode includes a negative current collector and a negative active layer disposed on at least one side of the negative current collector. The negative active layer may include negative active materials, conductive agents, and binders. The positive active materials, negative active materials, and conductive agents and binders in the positive and negative electrode sheets can all be conventional materials in the art, and there are no particular limitations.

[0214] For example, the positive electrode active material may include lithium-containing active materials, which may include one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, ternary materials, lithium manganese oxide and lithium nickel oxide, wherein the ternary materials may include nickel cobalt manganese ternary materials (NCM) and / or nickel cobalt aluminum ternary materials (NCA).

[0215] In this embodiment of the invention, the battery includes a lithium-ion battery, a sodium-ion battery, a potassium-ion battery, a magnesium-ion battery, or a zinc-ion battery; the lithium-ion battery system may include a lithium cobalt oxide battery, a lithium iron phosphate battery, a lithium manganese iron phosphate battery, a ternary cathode battery, a lithium manganese oxide battery, or a lithium nickel oxide battery, preferably the ternary cathode battery includes a nickel-cobalt-manganese ternary battery or a nickel-cobalt-aluminum ternary battery.

[0216] In addition, the negative electrode active material may include one or more of carbon-based negative electrode active materials, silicon-based negative electrode active materials, and titanium-based negative electrode active materials. The carbon-based negative electrode active material may include one or more of graphite, hard carbon, and soft carbon. The silicon-based negative electrode active material may include one or more of silicon-carbon materials, silicon-oxygen materials, and elemental silicon. The titanium-based negative electrode active material may include lithium titanate.

[0217] In this embodiment of the invention, the battery can be a liquid battery, a semi-solid battery, or a solid battery.

[0218] The present invention also provides a battery pack, the battery pack including a housing and the battery described above, the battery being located inside the housing.

[0219] Specifically, the housing may include a tray (such as...) Figure 10 (as shown) and a sealing cap, which covers the tray to enclose the housing as a storage space for holding the battery.

[0220] The battery in this embodiment of the invention can be a module-less structure or a module-based structure. When the battery is a module-less structure, the battery (including the heat-absorbing component and the cell assembly present on at least one side of the heat-absorbing component) can be directly placed in the casing to obtain a battery pack. When the battery pack is a module-based structure, the battery also includes a side plate surrounding the heat-absorbing component and the cell assembly, and then the battery with the module-based structure is placed in the casing to obtain a battery pack.

[0221] This invention also provides an electrical device including the aforementioned battery. The invention does not specifically limit the type of electronic device, but includes, but is not limited to, mobile phones, portable devices, laptops, electric bicycles, electric cars, electric toys, energy storage devices, etc. By using the aforementioned battery in electronic devices, electrical energy can be continuously and stably output to supply power to the electronic devices, resulting in a longer service life. Simultaneously, the battery's superior thermal safety protection capabilities contribute to the high safety performance of the aforementioned electrical device.

[0222] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0223] Example 1

[0224] This embodiment refers to 3 battery cell groups and 2 heat absorption components. Figure 1A The arrangement shown is for reference only; the spacing between heat-absorbing components and the number of cells are not considered. Figure 1A The components are assembled into a battery, with a cell group between the two heat-absorbing components; each cell group includes 20 cells, that is, the number of cells n2 between the heat-absorbing components is 20.

[0225] All cells in the battery are identical in size and shape. The capacity of a single cell (C) is 153 Ah, the cell dimensions are 960mm*90mm*13.5mm, the cell thickness (the dimension of a single cell in the direction of arrangement of multiple cells and heat-absorbing components) is 13.5mm, the rated capacity of the cell (Qc) is 1958kJ, and the specific heat capacity of the cell (C) is... p The efficiency is 1 kJ / (kg·K), and the mass m of a single cell is 2.6 kg;

[0226] The heat-absorbing component includes a heat-absorbing composite material and a shell disposed outside the heat-absorbing composite material. The shell includes a shell body and a cover plate. The cover plate is used to close the shell body to enclose and form a cavity. The heat-absorbing composite material is located inside the cavity. The shell thickness is 0.3 mm and the material is aluminum shell (tri-aluminum 3003). The cover plate thickness is 0.3 mm and the material is aluminum shell (tri-aluminum 3003).

[0227] The heat-absorbing composite material includes a support layer and a heat-absorbing material. The heat-absorbing material includes heat-absorbing materials located on opposite sides in the thickness direction (i.e., the first direction) of the support layer and in the hexagonal pores inside the support layer. The support layer includes honeycomb aluminum material. The heat-absorbing material includes polyacrylamide hydrogel material, wherein the phase change material is water.

[0228] The mass content r of phase change material in the heat-absorbing material is 84%;

[0229] The density ρ of the heat-absorbing material is 1000 kg / m³ 3 ;

[0230] The cavity's dimension x1 in the first direction is 8 mm;

[0231] The area S of the heat-absorbing composite material projected onto a plane perpendicular to the first direction is 62562 mm². 2 ;

[0232] The ratio a of the area of ​​the support layer projected onto the plane perpendicular to the first direction to S is 0.32.

[0233] The number of layers n1 of the support unit is 1;

[0234] The single-layer support unit has a dimension of 5mm x2 in the first direction;

[0235] The total thickness of the support layer, n1*x2, is 5mm;

[0236] Based on the above conditions, the following can be calculated:

[0237]

[0238] x1-n1x2,

[0239]

[0240]

[0241] The results are shown in Tables 3 and 4.

[0242] The differences between Examples 2-41, Comparative Examples 1-9 and Example 1 are: the number of cells n2 between the heat-absorbing components, the rated capacity Qc of the cells, and the specific heat capacity C of the cells. pThe specific parameters such as the mass m of a single battery cell, the mass content r of phase change material in the heat-absorbing material, the density ρ of the heat-absorbing material, the dimension x1 of the cavity in the first direction, the area S of the orthographic projection of the heat-absorbing composite material on the plane perpendicular to the first direction, the ratio a of the area a of the orthographic projection of the support layer on the plane perpendicular to the first direction to S, the number of support unit layers n1, n1*x2, etc. are shown in Tables 1 and 2. Except for the differences between Tables 1 and 2, the other conditions are the same as in Example 1.

[0243] Table 1

[0244]

[0245]

[0246]

[0247] Table 2

[0248]

[0249]

[0250]

[0251] Test case

[0252] The batteries in the examples and comparative examples were used as test samples and assembled into... Figure 9 In the test equipment shown, U1-U3 are pressure sensors; 1#-10# are battery cells, which are arranged according to... Figure 9 The cells are arranged according to the positive and negative polarity of the markings to form a battery pack; Figure 9 The four-pointed star on cell #6 is the needle penetration point; the dots corresponding to 1-41 are temperature sensors used to test the temperature of various parts inside the battery after the needle penetration test. The test fixture is formed by calcium silicate plates and aluminum plates. The calcium silicate plates are set at both ends of the first direction (the arrangement direction of cell group 2 and heat absorption component 1 in the battery), with two adjacent calcium silicate plates at each end. The pressure sensor is set between two adjacent calcium silicate plates. The surface of the battery in the thickness direction (the first direction, i.e., the arrangement direction of the heat absorption component and the cell group present on at least one side of the heat absorption component) is insulated from the calcium silicate plate by a heat insulation material (e.g., aerogel). The battery is constrained by the heat insulation material and the calcium silicate plate. The large surface of the aluminum plate (the surface perpendicular to the thickness direction of the aluminum plate) is set parallel to the surface of the battery perpendicular to the first direction.

[0253] Charge the battery according to the standard procedure, then induce a voltage drop by puncturing the battery with a needle. Determine the degree of thermal runaway of the battery according to the following standards:

[0254] The needle penetration test included a state of charge (SOC) of 100% for the battery cells and an initial temperature of 45℃±2℃ for all cells in the battery. A 5mm straight steel needle was used to penetrate one of the cells between two adjacent heat-absorbing components at a speed of 1mm / s until thermal runaway occurred. The needle was then withdrawn after 2 minutes. The maximum penetration depth was 80mm (if thermal runaway occurred before reaching 80mm, penetration was stopped; if thermal runaway did not occur during penetration, the maximum penetration depth was 80mm, and penetration was stopped after reaching 80mm). The test was continued until the temperature of all cells in the battery was below 100℃. During this process, thermal diffusion was recorded between adjacent cells (cells on the other side of the heat-absorbing components). The battery was also disassembled to observe whether the heat-absorbing composite material was damaged and whether the internal skeleton was deformed. The evaluation results are shown in Table 3 (whether the heat-absorbing material was extruded and whether the skeleton was deformed).

[0255] The following criteria shall be used to determine whether a battery cell has experienced thermal runaway:

[0256] a) The triggering object generates a voltage drop, and the drop value exceeds 25% of the initial voltage;

[0257] b) The temperature at any monitoring point reaches the manufacturer's specified maximum operating temperature of 180°C;

[0258] c) The temperature rise rate dT / dt at any monitoring point is ≥1℃ / s and lasts for more than 3s.

[0259] Thermal runaway is determined to have occurred when a) and c) occur simultaneously or when b) and c) occur simultaneously.

[0260] Monitoring the cells in the embodiments and comparative examples, excluding the two heat-absorbing components (i.e., the cells on the other side of the first direction of the two heat-absorbing components other than the cells subjected to needle puncture), includes:

[0261] If none of the cells on the other side of the heat-absorbing component are out of control, it is classified as STP (no thermal diffusion occurs in the cells); if any cell on the other side of the heat-absorbing component is out of control, it is classified as TP (thermal diffusion occurs in the battery). The evaluation results are shown in Table 3 (Safety Evaluation).

[0262] The battery pack prepared above was subjected to the following performance tests:

[0263] 1. Decrease in volumetric energy density

[0264] The battery pack will be subjected to charge-discharge tests to obtain its battery capacity. The volumes of the cells and the water-bearing layer will be measured and calculated. The volumetric energy density and volumetric energy density reduction rate of a single cell will be obtained using the following formulas:

[0265] Volumetric energy density of a single battery cell = Capacity of a single battery cell / Volume of a single battery cell;

[0266] The volumetric energy density of a single new battery cell = the capacity of a single battery cell / (the volume of a single battery cell + the volume of the aquifer);

[0267] Volumetric energy density reduction rate = (volumetric energy density of a single cell - volumetric energy density of a single new cell) / volumetric energy density of a single cell.

[0268] The evaluation results are shown in Tables 3 and 4.

[0269] Table 3

[0270]

[0271]

[0272]

[0273] "-" indicates that the support layer is too thick, making it impossible to assemble the battery and thus preventing the data from being tested.

[0274] Table 4

[0275]

[0276]

[0277]

[0278] As can be seen from the table, Embodiments 1-41 of the present invention, compared with Comparative Examples 1-9, further control the battery... and, This gives the battery better thermal safety protection capabilities and can effectively prevent heat diffusion. Furthermore, the batteries in Examples 1-24, 27-30, and 32-34 further meet the requirements compared to those in Examples 25, 31, and 40-41. This ensures that the heat-absorbing material is not squeezed out of the explosion-proof valve after thermal runaway occurs in the battery cell, further improving the safety and reliability of the battery. The thermal management effect of the batteries in Examples 1-24, 27-30, and 32-34 is further improved; compared with the batteries in Examples 26, 31, and 40, the batteries in Examples 1-24, 27-30, and 32-34 further meet... This results in the support layer in the former having better mechanical properties. After thermal runaway occurs in the battery cell, the support layer will not deform, thus exhibiting high thermal management performance. Examples 1-24, 27-30, and 32-34, compared to Example 39, show that when the battery meets... The battery's energy density degradation rate is not high, ensuring that the battery has a high volumetric energy density; Examples 1-24, 27-30, and 32-34, compared to Example 40, when the battery meets the following requirements... This allows the battery to maintain good thermal management while ensuring a high volumetric energy density. Compared to Example 41, Examples 1-24, 28-30, and 32-34 have a support layer with a suitable thickness, which enables the heat-absorbing material to have better mechanical properties. This prevents the heat-absorbing material from being squeezed out of the explosion-proof valve after thermal diffusion occurs in the battery, further improving the battery's thermal management performance.

[0279] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery, characterized in that, The battery includes a heat-absorbing component and a cell assembly located on at least one side of the heat-absorbing component; The battery pack includes battery cells; The heat-absorbing assembly includes a housing and a heat-absorbing composite material located in a cavity enclosed by the housing, the heat-absorbing composite material including a support layer and a heat-absorbing material disposed on the support layer; The heat-absorbing material includes a phase change material; The support layer includes at least one support unit stacked along a first direction of the heat-absorbing composite material; The first direction is the arrangement direction of the heat-absorbing component and the battery cell group present on at least one side of the heat-absorbing component; The battery satisfies: and, Wherein, r is the mass content of the phase change material in the heat-absorbing material, expressed in %; ρ is the density of the heat-absorbing material, in kg / m³. 3 count; S is the area of ​​the heat-absorbing composite material projected onto a plane perpendicular to the first direction, in mm. 2 count; x1 is the dimension of the cavity in the first direction, in mm; a is the ratio of the area of ​​the support layer projected onto a plane perpendicular to the first direction to S; n1 is the number of layers in the support unit; x2 is the dimension of a single-layer support unit in the first direction, in mm; Qc is the rated energy of the battery cell, expressed in kJ. n2 is the number of battery cells in the battery cell group, where n2 ≥ 2 and n2 is an integer; C p The specific heat capacity of the battery cell is expressed in kJ / (kg·K). m represents the mass of a single battery cell, expressed in kg.

2. The battery according to claim 1, characterized in that, The battery satisfies: And / or, 3. The battery according to claim 1 or 2, characterized in that, The battery satisfies: x1-n1x2≤16.

4. The battery according to any one of claims 1-3, characterized in that, The battery satisfies:

5. The battery according to any one of claims 1-4, characterized in that, The battery satisfies:

6. The battery according to any one of claims 1-5, characterized in that, The battery satisfies:

7. The battery according to any one of claims 1-6, characterized in that, The percentage of r is 80-99%; And / or, the ρ is 900–1200 kg / m³ 3 ; And / or, S is 8000~600000mm 2 ; And / or, the x1 is 8 to 30 mm; And / or, the percentage of a is 10% to 50%; And / or, n1*x2 is 3 to 30 mm; And / or, the Qc is 576–7200 kJ; And / or, n2 is 3 to 30; And / or, the C p It ranges from 0.8 to 1.2 kJ / (kg·K). And / or, the m is 1 to 4 kg.

8. The battery according to any one of claims 1-7, characterized in that, The first direction is the thickness direction of the heat-absorbing component.

9. The battery according to any one of claims 1-8, characterized in that, The heat-absorbing component is provided between at least two adjacent battery cell groups.

10. The battery according to any one of claims 1-9, characterized in that, The heat-absorbing component is provided between each pair of adjacent groups of the battery cells.

11. The battery according to any one of claims 1-10, characterized in that, The support layer includes pores, and at least a portion of the pores of the support layer are filled with the heat-absorbing material.

12. The battery according to any one of claims 1-11, characterized in that, At least a portion of the heat-absorbing material is also disposed on opposite sides of the support layer in the first direction; And / or, the support layer comprises at least two layers of the support units stacked along the first direction of the heat-absorbing composite material.

13. The battery according to any one of claims 1-12, characterized in that, The housing includes a housing body and a cover plate, the cover plate being used to close the housing body to enclose and form a cavity; And / or, at least one of the structures of the cover plate and the shell body is provided with an explosion-proof valve.

14. The battery according to claim 13, characterized in that, The shell body includes at least one of aluminum, steel, and aluminum-plastic film; And / or, the cover plate includes at least one of aluminum, steel, and aluminum-plastic film.

15. The battery according to any one of claims 1-14, characterized in that, The support layer includes at least one of aluminum, steel, ceramic, and glass fiber; And / or, the heat-absorbing material includes at least one of hydrogel, hydrated salt, and colloid.

16. The battery according to any one of claims 1-15, characterized in that, The battery also includes a cold plate located on at least one side of the cell assembly in a second direction, which intersects with the first direction.

17. The battery according to any one of claims 1-16, characterized in that, The battery cell includes at least one of lithium-ion batteries and sodium-ion batteries. Preferably, the lithium-ion battery includes a positive electrode active material, which includes one or more of lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium manganese oxide, and lithium nickel oxide.

18. The battery according to any one of claims 1-17, characterized in that, The battery cell includes a negative electrode active material, which includes one or more of carbon-based, silicon-based, and titanium-based negative electrode active materials. Preferably, the carbon-based anode active material includes one or more of graphite, hard carbon, and soft carbon; the silicon-based anode active material includes one or more of silicon-carbon materials, silicon-oxygen materials, and elemental silicon; and the titanium-based anode active material includes lithium titanate.

19. The battery according to any one of claims 1-18, characterized in that, The battery is a liquid battery, a semi-solid battery, or a solid battery.

20. A battery pack, characterized in that, The battery pack includes a housing and a battery as described in any one of claims 1-19, wherein the battery is located within the housing.

21. An electrical appliance, characterized in that, The electrical equipment includes the battery as described in any one of claims 1-19 or the battery pack as described in claim 20.

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