Heat-absorbing composite material, heat-absorbing component, battery module and electrical device

Abstract

Provided in the present application are a heat-absorbing composite material, a heat-absorbing component, a battery module and an electrical device. The heat-absorbing composite material comprises a framework and a heat-absorbing material; the heat-absorbing material comprises a phase change material, pores of the framework being filled with the heat-absorbing material; a first surface of the heat-absorbing composite material is located between a second surface thereof and a battery cell. 0.2≤2252×r×ρ(S×x-a×H)×10-9 / (0.6×Qc-360×cp×M)≤30, r being the mass content of the phase change material in the heat-absorbing material, ρ being the density of the heat-absorbing material in the unit of kg / m3, x being the thickness of the heat-absorbing composite material in the unit of mm, S being the area of the first surface in the unit of mm2, a being the area of the orthographic projection of the framework on the first surface in the unit of mm2, H being the thickness of the framework in the unit of mm, Qc being the capacity of the battery cell in the unit of KJ, cp being the specific heat capacity of the battery cell in the unit of kJ·kg-1·K-1, and M being the mass of the battery cell in the unit of kg.

Description

Heat-absorbing composite materials, heat-absorbing parts, battery components and electrical equipment

[0001] This application claims priority to a Chinese patent application filed with the Patent Office of China on March 29, 2024, with application number 202410381374.6 and entitled “Heat-absorbing composite materials, heat-absorbing parts, battery assemblies and electrical equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to heat-absorbing composite materials, heat-absorbing parts, battery assemblies and electrical equipment. Background Art

[0003] Battery cells power electrical devices, and temperature fluctuations during use affect the performance and safety of both the cells and the devices. Related technologies employ heat-absorbing materials placed on the surface of battery cells to remove heat generated by the cells through processes such as phase change, thereby preventing thermal diffusion and thermal runaway. However, current heat-absorbing materials are susceptible to damage when subjected to external forces, thus compromising their heat absorption effectiveness. Summary of the Invention

[0004] In view of this, the present application provides a heat-absorbing composite material, a heat-absorbing component, a battery assembly and an electrical device. The heat-absorbing material can take into account excellent heat absorption performance and mechanical properties, which is conducive to the use of the heat-absorbing component and improves the performance of the battery assembly and the electrical device.

[0005] In a first aspect, the present application provides a heat-absorbing composite material for being arranged on the surface of a battery cell, comprising a skeleton and a heat-absorbing material, wherein the heat-absorbing material comprises a phase change material, the skeleton has a plurality of pores, and the pores are filled with the heat-absorbing material. Along the thickness direction of the skeleton, the heat-absorbing composite material has a first surface and a second surface arranged opposite to each other, the first surface is located between the second surface and the battery cell, r, ρ, x, S, a, H, Q c 、c p The value of M satisfies: 0.2≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤30, wherein r is the mass content of the phase change material in the endothermic material, and ρ is the density of the endothermic material, in kg / m 3 , x is the thickness of the heat-absorbing composite material, in mm, S is the area of ​​the first surface, in mm 2 , a is the area of ​​the orthographic projection of the skeleton on the first surface, in mm 2 , H is the thickness of the skeleton, in mm, Qc is the capacity of the battery cell in kJ, c p is the specific heat capacity of the battery cell, in kJ·kg -1 ·K -1 , M is the mass of the battery cell, in kg.

[0006] Optionally, the r, the p, the x, the S, the a, the H, the Q c 、the c p The value of M satisfies: 0.5≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤15.

[0007] Optionally, the r is 80% to 99%.

[0008] Optionally, the ρ is 900 kg / m 3 Up to 1200kg / m 3 .

[0009] Optionally, x is 0.35 mm to 7 mm.

[0010] Optionally, the S is 5000mm 2 Up to 600,000 mm 2 .

[0011] Optionally, the a is 500mm 2 Up to 270,000 mm 2 .

[0012] Optionally, H is 0.025 mm to 20 mm.

[0013] Optionally, the Q c 576kJ to 3456kJ.

[0014] Optionally, the c p 0.8 kJ·kg -1 ·K -1 to 1.2 kJ·kg -1 ·K -1 .

[0015] Optionally, M is 1 kg to 5 kg.

[0016] Optionally, along the thickness direction of the skeleton, the skeleton includes at least one layer of sub-skeleton, and H satisfies H=n×x1, wherein n is the number of layers of the sub-skeleton in the heat-absorbing composite material, and x1 is the thickness of the sub-skeleton, in mm.

[0017] Furthermore, n is an integer from 1 to 10.

[0018] Furthermore, the x1 is 0.025 mm to 2 mm.

[0019] Optionally, H is 0.05 mm to 5 mm.

[0020] Optionally, the values ​​of S and a satisfy: 0.1≤a / S≤0.45.

[0021] Optionally, the values ​​of r, x, S, a, and H satisfy: r×(x×Sa×H)≥11000.

[0022] Optionally, the values ​​of x, a, H, and S satisfy: a×H / (x×S)≥0.02.

[0023] Optionally, the values ​​of x and H satisfy: 1<x / H≤18.

[0024] Optionally, the heat-absorbing material includes a matrix and the phase-change material, the matrix is ​​a hydrophilic polymer material, and the phase-change material in the heat-absorbing material can be separated from the matrix when heated.

[0025] Furthermore, the heat-absorbing material is a hydrogel.

[0026] Optionally, the hole penetrates the skeleton along the thickness direction of the skeleton.

[0027] Furthermore, the holes uniformly penetrate the skeleton along the thickness direction of the skeleton.

[0028] In a second aspect, the present application provides a heat-absorbing component, comprising a packaging structure and the heat-absorbing composite material described in the first aspect, wherein the packaging structure has an accommodating space inside, and the heat-absorbing composite material is arranged in the accommodating space.

[0029] In a third aspect, the present application provides a battery assembly, comprising a battery cell and the heat absorption element described in the second aspect, wherein the heat absorption element is arranged on the surface of the battery cell; or the battery assembly comprises a battery cell and the heat absorption composite material described in the first aspect, wherein the heat absorption composite material is arranged on the surface of the battery cell.

[0030] Optionally, the battery cell has a third surface, which is in contact with the first surface; wherein the surface area of ​​the third surface is greater than or equal to the surface area of ​​the first surface; and / or the projection of the first surface on the third surface is accommodated in the third surface; and / or the shape of the first surface is the same as the shape of the third surface.

[0031] In a fourth aspect, the present application provides an electrical device comprising the battery assembly described in the third aspect.

[0032] The heat-absorbing composite material provided by the present application is provided by constraining the r, the ρ, the x, the S, the a, the H, the Q c 、the c p The relationship between the values ​​of M and M is within a certain range, ensuring that the heat-absorbing composite material has both excellent thermal absorption performance and excellent mechanical properties. This allows the overall structural integrity to be maintained even when subjected to external forces, resulting in excellent overall performance of the heat-absorbing composite material and improved battery assembly safety. Heat-absorbing components containing this heat-absorbing composite material exhibit excellent thermal absorption and mechanical properties, further facilitating the use of electrical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0034] FIG1 is a schematic cross-sectional view of a heat-absorbing composite material provided in one embodiment of the present application;

[0035] FIG2 is a schematic structural diagram of a skeleton provided in one embodiment of the present application;

[0036] FIG3 is a top view of a skeleton provided in one embodiment of the present application;

[0037] FIG4 is an enlarged view of a portion of FIG3 ;

[0038] FIG5 is a schematic structural diagram of a two-layer sub-skeleton provided in one embodiment of the present application;

[0039] FIG6 is a schematic cross-sectional view of a heat-absorbing composite material provided in another embodiment of the present application;

[0040] FIG7 is a schematic cross-sectional view of a heat absorbing element provided in one embodiment of the present application;

[0041] FIG8 is a schematic cross-sectional view of a battery assembly provided in one embodiment of the present application;

[0042] FIG9 is a schematic cross-sectional view of a battery assembly provided in another embodiment of the present application;

[0043] FIG10 is a schematic structural diagram of an electrical device provided in one embodiment of the present application. Specific embodiments

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] The heat generated during battery cell use, as well as thermal runaway caused by thermal or mechanical abuse, can both affect the cell's usability. Current endothermic materials have weak compressive strength and are unable to effectively reduce cell heat and prevent thermal runaway when subjected to external forces (such as expansion forces from cell expansion), thus impacting the cell's usability. While an endothermic skeleton can be used in conjunction with the endothermic material to improve its compressive strength, the skeleton takes up space, reduces the amount of endothermic material, or increases the overall weight, making it unsuitable for use in battery cells.

[0046] Please refer to Figure 1, which is a cross-sectional schematic diagram of an endothermic composite material provided in one embodiment of the present application, and please refer to Figure 2, which is a structural schematic diagram of a skeleton provided in one embodiment of the present application. The endothermic composite material 100 is used to be arranged on the surface of the battery cell, including a skeleton 10 and an endothermic material 20. The endothermic material 20 includes a phase change material. The skeleton 10 has a plurality of holes 11, and the holes 11 are filled with the endothermic material 20. Along the thickness direction of the skeleton 10, the endothermic composite material 100 has a first surface 101 and a second surface 102 arranged opposite to each other. The first surface 101 is located between the second surface 102 and the battery cell. r, ρ, x, S, a, H, Q c 、c p The value of M satisfies: 0.2≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤30, where r is the mass content of the phase change material in the endothermic material 20, and ρ is the density of the endothermic material 20, in kg / m 3 , x is the thickness of the heat-absorbing composite material 100, in mm, S is the area of ​​the first surface 101, in mm 2 , a is the area of ​​the orthographic projection of the skeleton 10 on the first surface 101, in mm 2 , H is the thickness of the frame 10, in mm, Q c is the capacity of the battery cell in kJ, c p is the specific heat capacity of the battery cell, in kJ·kg -1 ·K -1, M is the mass of the battery cell, in kg. The endothermic composite material 100 provided herein includes a skeleton 10 and an endothermic material 20 at least partially disposed within the pores 11 of the skeleton 10. By controlling the relationship between the skeleton 10, the endothermic material 20, and the relevant parameters of the battery cell, the endothermic composite material 100 exhibits excellent heat absorption performance while maintaining a high level of mechanical properties, particularly compression resistance. This allows the composite material 100 to maintain overall structural integrity even when subjected to external forces (such as the expansion force generated by the expansion of the battery cell), preventing problems such as extrusion of the endothermic material 20. This further ensures its heat absorption effect and facilitates its use.

[0047] The heat-absorbing material 20 in this application can be selected as needed, and absorbs heat by utilizing the phase change process of the phase change material within the heat-absorbing material 20. In one embodiment of this application, the heat-absorbing material 20 comprises a matrix and a phase change material. The matrix is ​​a hydrophilic polymer material, and the phase change material within the heat-absorbing material 20 can be separated from the matrix upon heating. The hydrophilic polymer material facilitates the accommodation of the phase change material, increases the mass content of the phase change material within the heat-absorbing material 20, and enhances the heat-absorbing performance of the heat-absorbing composite material 100. In one embodiment of this application, the heat-absorbing material 20 is a hydrogel. The heat-absorbing performance is achieved by the phase change process (from liquid water to gaseous water) of the water within the hydrogel.

[0048] In this application, r represents the mass content of the phase change material in the endothermic material 20, which can be measured using a thermogravimetric analyzer. The mass content of the phase change material in the endothermic material 20 affects the heat absorption capacity of the endothermic composite material 100 during the endothermic process. In one embodiment of the present application, r is 80% to 99%, which allows the endothermic material 20 to have a high latent heat of phase change, thereby absorbing a large amount of heat during the phase change process and improving the heat absorption performance of the endothermic composite material 100. Specifically, r can be, but is not limited to, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%, etc. In one embodiment of the present application, r can be 82% to 95%, further improving the heat absorption performance of the endothermic material 20 and, to a certain extent, enhancing the mechanical properties of the endothermic material 20 itself, thereby improving the performance of the endothermic composite material 100. In another embodiment of the present application, r can be 85% to 90%. In another embodiment of the present application, r can be 87% to 95%. In one embodiment of the present application, the phase change material can be water.

[0049] In this application, ρ is the density of the heat absorbing material 20. By detecting the mass and volume of the heat absorbing material 20, the density of the heat absorbing material 20 can be calculated. In one embodiment of this application, ρ is 900 kg / m 3 Up to 1200kg / m3 The density of the heat absorbing material 20 is appropriate, thereby avoiding excessive density and thus excessive increase in the weight of the heat absorbing composite material 100 and the heat absorbing component, which is conducive to the use of the heat absorbing component in the battery assembly and further improves the energy density of the battery assembly. Specifically, ρ can be but is not limited to 900 kg / m 3 , 920kg / m 3 , 950kg / m 3 , 980kg / m 3 , 1000kg / m 3 、1030kg / m 3 、1050kg / m 3 、1070kg / m 3 、1100kg / m 3 、1110kg / m 3 、1130kg / m 3 、1150kg / m 3 、1160kg / m 3 、1190kg / m 3 or 1200kg / m 3 In one embodiment of the present application, ρ can be 950 kg / m 3 Up to 1050kg / m 3 In another embodiment of the present application, ρ can be 1000 kg / m 3 Up to 1200kg / m 3 .

[0050] In this application, the mass content of the phase change material in the heat-absorbing material 20 and the density of the heat-absorbing material 20 jointly affect the total heat absorption of the heat-absorbing composite material 100. In one embodiment of the present application, r is 80% to 99%, and ρ is 900 kg / m 3 Up to 1200kg / m 3 , so that the endothermic composite material 100 takes into account both the total heat absorption and the mass, that is, the endothermic composite material 100 has a high total heat absorption and a low mass, so that when the endothermic composite material 100 is used in a heat-absorbing component, it can better protect the battery cell, prevent the battery cell itself from thermal runaway and heat transfer between battery cells, and at the same time ensure the proportion of battery cells in the battery assembly, thereby improving the volume energy density of the battery assembly.

[0051] In this application, the framework 10 supports, secures, and confines the heat-absorbing material 20, thereby improving the mechanical properties of the heat-absorbing composite material 100. The framework 10 has multiple pores 11, which are filled with the heat-absorbing material 20. The heat-absorbing material 20 can fill all or part of the pores 11. The opening shapes of the pores 11 of the framework 10 can be, but are not limited to, polygonal (e.g., square, rectangle, hexagon, octagon, diamond, triangle, etc.), circular, elliptical, semicircular, or irregular, and can be selected based on specific needs.

[0052] In one embodiment of the present application, the holes 11 extend through the skeleton 10 along its thickness. It will be appreciated that the direction from the first surface 101 to the second surface 102 corresponds to the thickness of the skeleton 10. In other words, the holes 11 in this embodiment are through holes, which facilitates the filling and dispersion of the heat-absorbing material 20. In another embodiment of the present application, the holes 11 do not extend through the skeleton 10 along its thickness. In this embodiment, the holes 11 in the skeleton 10 may be through holes, blind holes, or partially through holes and partially blind holes. In one embodiment of the present application, all of the holes 11 extend through the skeleton 10 along its thickness. In another embodiment of the present application, the holes 11 extend uniformly through the skeleton 10 along its thickness. In other words, along the thickness of the skeleton 10, the holes 11 have the same diameter on cross-sections perpendicular to the thickness of the skeleton 10, facilitating uniform filling of the heat-absorbing material 20 within the skeleton 10 and improving the overall support performance of the skeleton 10.

[0053] In one embodiment of the present application, as shown in Figure 2 , the openings of the holes 11 of the skeleton 10 are square. Referring to Figure 3 , which is a top view of the skeleton 10 provided in one embodiment of the present application, and Figure 4 , which is an enlarged view of a portion of Figure 3 , it can be seen that the openings of the holes 11 of the skeleton 10 are hexagonal.

[0054] In one embodiment of the present application, the material of the skeleton 10 may be, but is not limited to, at least one of polyester, polypropylene, and glass fiber. The skeleton 10 made of the above materials has better supporting performance and mechanical properties.

[0055] In this application, H represents the thickness of the skeleton 10, which can be obtained by measurement, specifically, but not limited to, measurement using a vernier caliper. In one embodiment of the present application, the thickness of the skeleton 10 is less than the thickness of the endothermic composite material 100, ensuring the proportion of the endothermic material 20 in the endothermic composite material 100 and improving the heat absorption performance of the endothermic composite material 100. In one embodiment of the present application, H is 0.025 mm to 20 mm, which is beneficial for improving the mechanical properties of the endothermic composite material 100 while ensuring the heat absorption performance of the endothermic composite material 100. Specifically, H can be, but is not limited to, 0.025 mm, 0.05 mm, 0.1 mm, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 7 mm, 9 mm, 10 mm, 15 mm, 18 mm, or 20 mm. Furthermore, in one embodiment of the present application, H can be 0.05 mm to 10 mm. Still further, in one embodiment of the present application, H can be 0.05 mm to 5 mm. This helps further ensure the overall thickness of the skeleton 10 in the endothermic composite material 100, while improving the mechanical properties of the endothermic composite material 100 while ensuring the content of the endothermic material 20 in the endothermic composite material 100. This allows the endothermic composite material 100 to achieve both mechanical properties (such as compressive strength) and heat absorption performance. Furthermore, when the endothermic composite material 100 is used in a battery pack, the volumetric energy density reduction rate of the battery pack remains within a reasonable range. That is to say, the numerical value of H satisfies: 0.05≤H≤5. Specifically, the lower limit value of H may be, but is not limited to, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.3, 1.5, 1.7, 1.8, 2, 2.3 or 2.5, etc.; the upper limit value of H may be, but is not limited to, 1, 1.2, 1.5, 1.9, 2, 2.5, 2.8, 3, 3.3, 3.5, 3.7, 4, 4.3, 4.5, 4.9 or 5, etc.

[0056] In one embodiment of the present application, the skeleton 10 includes at least one layer of sub-skeleton along the thickness direction of the skeleton 10. That is, one or more sub-skeletons are stacked to form the skeleton. H satisfies H = n × x1, where n is the number of sub-skeleton layers in the endothermic composite material 100, n is an integer greater than or equal to 1, and x1 is the thickness of the sub-skeleton in mm. In one embodiment of the present application, n is an integer from 1 to 10. That is, the number of sub-skeleton layers in the endothermic composite material 100 can be, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 layers. The number of sub-skeleton layers in the endothermic composite material 100 improves the mechanical properties of the endothermic composite material 100. At the same time, the above number of layers does not excessively increase the weight of the endothermic composite material 100 or reduce the proportion of the endothermic material 20 in the endothermic composite material 100, thereby ensuring the heat absorption performance of the endothermic composite material 100 and reducing the difficulty of preparing the endothermic composite material 100. In one embodiment of the present application, as shown in FIG1 , the skeleton 10 in the endothermic composite material 100 is composed of a single layer of sub-skeletons. FIG5 is a schematic diagram of the structure of a two-layer sub-skeleton according to one embodiment of the present application. The sub-skeletons in the endothermic composite material 100 are two layers, stacked along their thickness. FIG6 is a schematic cross-sectional diagram of another embodiment of the endothermic composite material 100, wherein the skeleton 10 in the endothermic composite material 100 is composed of three layers of sub-skeletons. In one embodiment of the present application, the endothermic composite material 100 comprises multiple layers of sub-skeletons, stacked along their thickness. The sub-skeletons have multiple pores extending through the thickness of the sub-skeletons. At least some of the pores in adjacent layers of sub-skeletons are connected, forming pores 11 in the skeleton 10, which facilitates the filling of the endothermic material 20. In one embodiment of the present application, the endothermic composite material 100 comprises multiple layers of sub-skeletons, with the pores in adjacent layers aligned and connected one-to-one, forming pores 11 in the skeleton 10.

[0057] In this application, x1 represents the thickness of the composite material 100, which can be obtained by measurement, specifically, but not limited to, measurement with a vernier caliper. In one embodiment of the present application, x1 is 0.025 mm to 2 mm, which can support the endothermic material 20 and improve the mechanical properties of the endothermic composite material 100 while ensuring the proportion of the endothermic material 20 in the endothermic composite material 100 and the heat absorption performance of the endothermic composite material 100. Specifically, x1 can be, but is not limited to, 0.025 mm, 0.03 mm, 0.05 mm, 0.07 mm, 0.1 mm, 0.3 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.7 mm, 1.9 mm, or 2 mm. In one embodiment of the present application, x1 can be 0.05 mm to 1 mm. In another embodiment of the present application, x1 can be 1 mm to 2 mm.

[0058] In the endothermic composite material 100 of the present application, the skeleton 10 and the endothermic material 20 are stacked, and the endothermic material 20 also fills the holes 11 of the skeleton 10. The thickness direction of the skeleton 10 is the stacking direction. Along the thickness direction of the skeleton 10, the endothermic composite material 100 has a first surface 101 and a second surface 102 arranged opposite to each other. The first surface 101 is located between the second surface 102 and the battery cell, that is, the first surface 101 can be directly or indirectly attached to the battery cell. S is the area of ​​the first surface 101, wherein the size of the first surface 101 can be measured based on the shape of the first surface 101, and the area of ​​the first surface 101 can be calculated. In one embodiment of the present application, S is 5000mm 2 Up to 600,000 mm 2 , so that the heat absorption area of ​​the heat absorption composite material 100 is larger, thereby improving the heat absorption effect of the heat absorption composite material 100, while avoiding waste caused by an excessively large area. Specifically, S can be, but is not limited to, 5000mm 2 , 10000mm 2 、30000mm 2 , 50000mm 2 , 70000mm 2 、100000mm 2 , 200000mm 2 、300000mm 2 、400000mm 2 , 500000mm 2 or 600000mm 2 In one embodiment of the present application, S may be 5000 mm. 2 Up to 50000mm 2 In another embodiment of the present application, S can be 50000 mm 2 Up to 300,000 mm 2 In another embodiment of the present application, S can be 300000 mm 2 Up to 600,000 mm 2. In one embodiment of the present application, the battery cell has a third surface, and the third surface is bonded to the first surface 101, wherein the surface area of ​​the third surface is greater than or equal to the surface area of ​​the first surface 101; and / or the projection of the first surface 101 on the third surface is contained within the third surface; and / or the shape of the first surface 101 is the same as the shape of the third surface. That is, the area of ​​the third surface is greater than or equal to the area of ​​the first surface 101, and / or the projection of the first surface 101 on the third surface falls within the third surface, and / or the shape of the first surface 101 is the same as the shape of the third surface, so that the first surface 101 of the endothermic composite material 100 can be completely bonded to the surface of the battery cell, thereby improving the heat absorption effect of the endothermic composite material 100. Preferably, the endothermic composite material 100 is directly bonded to the third surface of the battery cell, so the area of ​​the third surface of the battery cell is the area of ​​the first surface 101 of the endothermic composite material 100, so as to simplify the measurement difficulty.

[0059] In this application, "a" represents the area of ​​the orthographic projection of the skeleton 10 on the first surface 101. The endothermic composite material 100 has a first surface 101 and a second surface 102 disposed opposite each other along the thickness direction of the skeleton 10. The area of ​​the orthographic projection of the skeleton 10 on the first surface 101 is the orthographic projection area of ​​the physical structure of the skeleton 10 on the first surface 101. It will be understood that when the holes 11 do not penetrate the skeleton 10, the area of ​​the orthographic projection of the skeleton 10 on the first surface 101 is the entire area of ​​the orthographic projection of the skeleton 10 on the first surface 101. When at least a portion of the holes 11 penetrate the skeleton 10, the area of ​​the orthographic projection of the skeleton 10 on the first surface 101 is the orthographic projection area of ​​the portion of the holes 11 in the skeleton 10 that does not penetrate the skeleton 10 on the first surface 101. There are many methods for measuring the area of ​​the orthographic projection of the skeleton 10 on the first surface 101. For example, the orthographic projection area of ​​the entire skeleton 10 (including the through holes 11) can be measured and the orthographic projection area of ​​the through holes 11 can be subtracted. The orthographic projection area can be calculated by geometric structure parameters. The orthographic projection area of ​​the skeleton 10 (excluding the through holes 11) can also be directly obtained by three-dimensional digital modeling. The specific operation method can be selected according to actual needs. In one embodiment of the present application, a is 500mm 2 Up to 270,000 mm 2 , which can ensure that the frame 10 fixes and protects the heat absorbing material 20, and also ensures the heat absorbing performance of the heat absorbing composite material 100. Specifically, a can be but is not limited to 500mm 2 , 1000mm 2 , 3000mm 2 , 5000mm 2 , 8000mm 2 , 10000mm 2 、30000mm 2, 70000mm 2 , 90000mm 2 、100000mm 2 、140000mm 2 、150000mm 2 、180000mm 2 , 200000mm 2 , 220000mm 2 , 250000mm 2 or 270000mm 2 wait.

[0060] In one embodiment of the present application, the values ​​of S and a satisfy the following: 0.1 ≤ a / S ≤ 0.45. This ensures that the skeleton 10 secures and protects the endothermic material 20, preventing damage to the endothermic material 20 when the endothermic composite material 100 is subjected to external forces. It also ensures the proportion of the endothermic material 20 in the endothermic composite material 100, thereby improving the heat absorption performance of the endothermic composite material 100. Specifically, a / S can be, but is not limited to, 0.1, 0.12, 0.15, 0.18, 0.2, 0.23, 0.25, 0.27, 0.3, 0.33, 0.35, 0.36, 0.38, 0.4, 0.41, 0.43, or 0.45. In one embodiment of the present application, a / S can be between 0.1 and 0.2. In another embodiment of the present application, a / S can be between 0.2 and 0.3. In yet another embodiment of the present application, a / S can be between 0.36 and 0.45.

[0061] In this application, x is the thickness of the endothermic composite material 100, which can be obtained by measurement, specifically, but not limited to, measurement with a vernier caliper. In one embodiment of the present application, x is 0.35mm to 7mm, which not only ensures the heat absorption effect of the endothermic composite material 100, but also makes the endothermic composite material 100 have a lower mass, which is conducive to its use in battery components. Specifically, x can be, but is not limited to, 0.35mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.3mm, 5mm, 5.7mm, 6mm, 6.5mm or 7mm, etc. In one embodiment of the present application, x can be 0.35mm to 2.7mm, which is conducive to further improving the volume energy density in the battery component and is more conducive to the use of the battery component. In another embodiment of the present application, x can be 2mm to 4mm. In yet another embodiment of the present application, x can be 4mm to 7mm.

[0062] In one embodiment of the present application, the values ​​of r, x, S, a, and H satisfy the following: r×(x×Sa×H)≥11000. This allows the heat-absorbing composite material 100 to have high heat absorption performance, making it suitable for heat dissipation in large-capacity battery cells and improving the safety of the battery cells. Specifically, the value of r×(x×Sa×H) can be, but is not limited to, 11000 or greater, 12000 or greater, 14000 or greater, 15000 or greater, 18000 or greater, 19000 or greater, 20000 or greater, 21000 or greater, 23000 or greater, 25000 or greater, 27000 or greater, 29000 or greater, 30000 or greater, 40000 or greater, or 50000 or greater.

[0063] In one embodiment of the present application, the values ​​of x, a, and H satisfy the following: a×H / (x×S) ≥ 0.02. This further improves the compressive performance of the endothermic composite material 100, prevents deformation of the endothermic component, increases the compressive strength of the endothermic component, and enhances the structural reliability of the endothermic composite material 100 under the forces generated by the battery cell or other external forces. Specifically, the value of a×H / (x×S) can be, but is not limited to, 0.02 or greater, 0.025 or greater, 0.04 or greater, 0.06 or greater, 0.09 or greater, 0.1 or greater, 0.15 or greater, 0.2 or greater, 0.25 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, or 0.7 or greater. In addition, since a×H / (x×S)≥0.02 can be understood as the volume ratio of the skeleton 10 to the heat-absorbing composite material 100, when a×H / (x×S)≤0.02, the volume of the skeleton 10 accounts for too small a proportion, and the overall deformation or pressure-bearing capacity of the heat-absorbing composite material 100 is provided by the phase change material. As a result, the phase change material will diffuse out of the gap between the battery cells due to the influence of the battery expansion force or pre-tightening force, thereby causing the heat-absorbing composite material 100 to deform, thereby posing a safety risk in actual application.

[0064] In one embodiment of the present application, the values ​​of x and H satisfy the following: 1 < x / H ≤ 18. This allows the endothermic material 20 to protrude from the framework 10 in the thickness direction of the endothermic composite material 100, resulting in high heat absorption performance. This also further improves the mechanical properties and compressive strength of the endothermic composite material 100, thereby enhancing the structural reliability of the endothermic composite material 100 under forces generated by the battery cell or other external forces. Specifically, the value of x / H can be, but is not limited to, 1.5 or less, 2 or less, 3.5 or less, 5 or less, 8 or less, 10 or less, 11 or less, 13 or less, 14 or less, or 18 or less.

[0065] In this application c is the cell energy (fully charged), which can be obtained through battery load testing.c It can be obtained indirectly by measuring the cell terminal voltage and cell capacity, that is, Q c =V×q. Wherein, V is the terminal voltage of the battery cell (the terminal voltage in the fully charged state), q is the capacity of the battery cell, and the battery cell capacity can be measured by a charge and discharge test cabinet. The industry standard, i.e., 1 / 3C current, is generally used for charge and discharge testing. In one embodiment of the present application, Q c The battery cell can provide high electrical energy while generating relatively less heat when thermal runaway occurs. The thermal runaway is highly controllable, which improves the safety of battery components. c It may be, but is not limited to, 576kJ, 600kJ, 750kJ, 900kJ, 1000kJ, 1200kJ, 1500kJ, 1850kJ, 2000kJ, 2200kJ, 2500kJ, 2800kJ, 3000kJ, 3050kJ or 3300kJ. In one embodiment of the present application, Q c It can be 576kJ to 1500kJ. In another embodiment of the present application, Q c It can be from 1500kJ to 3456kJ.

[0066] In this application p is the specific heat capacity of the battery cell, which is obtained by measuring with a heat capacity meter or other instrument. p 0.8 kJ·kg -1 ·K -1 to 1.2 kJ·kg -1 ·K -1 Specifically, c p It can be but not limited to 0.8 kJ·kg -1 ·K -1 , 0.85kJ·kg -1 ·K -1 , 0.9kJ·kg -1 ·K -1 , 0.93kJ·kg -1 ·K -1 , 0.95kJ·kg -1 ·K -1 , 1kJ·kg -1 ·K -1 , 1.1 kJ·kg -1 ·K -1 or 1.2 kJ·kg -1 ·K -1 The specific heat capacity of a battery cell refers to the average specific heat capacity of all components of the battery cell, wherein all components of the battery cell may include: the battery cell shell, pole, pole core and other parts that constitute the battery cell.

[0067] In this application, M is the mass of the battery cell, which can be obtained by weighing. In one embodiment of the present application, M is 1kg to 5kg. Specifically, M can be, but is not limited to, 1kg, 1.5kg, 2kg, 2.5kg, 3kg, 3.5kg, 4kg, 4.3kg, 4.5kg, 4.8kg or 5kg, etc. The mass of the battery cell refers to the mass of all components of the battery cell, such as the battery cell casing, pole, pole core, and other components that constitute the battery cell.

[0068] The specific heat capacity and mass of the battery cell in this application jointly affect the heat capacity of the battery cell itself during thermal runaway. In one embodiment of this application, c p 0.8 kJ·kg -1 ·K -1 to 1.2 kJ·kg -1 ·K -1 , M is 1kg to 5kg, so that the battery core has an appropriate heat capacity, further ensuring the heat absorption effect of the heat absorption composite material 100 on the battery core and further improving the safety of the battery core.

[0069] It is understood that in this application, r, ρ, x, S, a, H, Q c 、c p , M are all measured before thermal runaway and under normal conditions. For example, M is the mass of the battery under normal conditions before thermal runaway. The above-mentioned normal state refers to the state where the battery cell can supply power normally. r, ρ, x, S, a, H, Q c 、c p The value of M satisfies: 0.2≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤30, the endothermic composite material 100 can have excellent heat absorption and mechanical properties, and when the endothermic composite material 100 is used in a battery assembly, it can further improve the volume energy density of the battery assembly, so that the battery assembly has excellent power supply capacity and safety performance. Specifically, 0.2≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c pThe lower limit of (S × M) ≤ 30 may be, but is not limited to, 0.2, 0.3, 0.4, 0.5, 1, 1.3, 1.5, 1.7, 2, 2.2, 2.5, 2.8, 3, 3.3, 3.5, 3.9, 4, 4.3, 4.5, 4.7, 5, 5.5, 5.8, 6, 6.4, 6.5, 6.8, 7, 7.1, 7.5, 7.6, 8, 8.3, 8.5, 8.8, 9, 9.2, 9.5, 9.6, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20; 0.2 ≤ 2252 × r × ρ (S × xa × H) × 10 -9 / (0.6×Q c -360×c p The upper limit of (xM)≤30 may be, but is not limited to, 7, 7.1, 7.5, 7.6, 8, 8.3, 8.5, 8.8, 9, 9.2, 9.5, 9.6, 10, 10.2, 10.5, 10.8, 11, 11.3, 11.5, 11.7, 12, 12.4, 12.5, 12.9, 13, 13.1, 13.5, 13.7, 14, 14.2, 14.5, 14.8, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30. In one embodiment of the present application, r, p, x, S, a, H, Q c 、c p The value of M satisfies: 0.5≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤15, which is beneficial to further improve the mechanical properties and heat absorption properties of the heat-absorbing composite material 100 and the volume energy density of the battery assembly, thereby improving the performance and safety of the battery.

[0070] Please refer to Figure 7, which is a cross-sectional schematic diagram of a heat sink according to one embodiment of the present application. Heat sink 300 includes an encapsulation structure 200 and a heat-absorbing composite material 100. Encapsulation structure 200 defines a housing space within which heat-absorbing composite material 100 is disposed. The encapsulation structure secures and restrains heat-absorbing composite material 100, ensuring the use of the heat sink while further improving its mechanical properties. This heat sink exhibits excellent heat absorption and mechanical properties, facilitating its use in battery assemblies.

[0071] In this application, the packaging structure is used to encapsulate the heat-absorbing composite material 100, and has an excellent water vapor barrier effect. In one embodiment of this application, the material of the packaging structure includes aluminum, which ensures the sealing effect of the packaging structure and improves the service life of the heat-absorbing component.

[0072] Please refer to Figure 8, which is a schematic cross-sectional view of a battery assembly according to one embodiment of the present application. Battery assembly 500 includes a battery cell 400 and a heat sink 300 according to any of the aforementioned embodiments, disposed on the surface of battery cell 400. In another embodiment of the present application, battery assembly 500 includes a battery cell 400 and a heat sink composite material 100 according to any of the aforementioned embodiments, disposed on the surface of battery cell 400. The battery cell 400 is prone to overheating under conditions such as thermal abuse and mechanical abuse. The heat absorber 300 or heat-absorbing composite material 100 provided in this application can absorb the heat generated by the battery cell 400, effectively reducing the probability of thermal runaway of the battery cell 400. In addition, the heat absorber 300 or heat-absorbing composite material 100 has excellent mechanical properties and good compression resistance. When the battery cell 400 expands, it can still maintain structural reliability and further maintain its original heat absorption performance. At the same time, the heat absorber 300 or heat-absorbing composite material 100 has a small volume share, which can effectively increase the proportion of the battery cell 400 in the battery assembly 500, improve the volume energy density of the battery, and facilitate the use of the battery assembly 500. In this application, the battery assembly 500 can be a battery pack or a battery module.

[0073] The battery assembly 500 of the present application may contain one or more battery cells 400. Please refer to Figure 9, which is a cross-sectional schematic diagram of a battery assembly 500 provided in another embodiment of the present application. The battery assembly 500 includes a plurality of battery cells 400, and a heat-absorbing member 300 is provided between adjacent battery cells 400. The provision of the heat-absorbing member 300 can also prevent the thermal runaway of the battery cell 400 from being transmitted to the adjacent battery cell 400, thereby enabling the normal battery cell 400 to continue to work and ensure the performance of the battery assembly 500. It can be understood that along the stacking direction of the battery cell 400 and the heat-absorbing member 300, the outermost side of the battery assembly 500 can be the battery cell 400 or the heat-absorbing member 300, and there is no limitation on this.

[0074] The present application provides an electric device 600, as shown in FIG10 , including a battery assembly 500. The electric device 600 provided in the present application has excellent performance and service life, and is highly competitive. Specifically, the electric device may be a vehicle, electronic equipment, energy storage system, etc.

[0075] The effects of the technical solution of this application are further illustrated below through specific examples.

[0076] Example A1

[0077] A heat-absorbing composite material 100 is used to be attached to the surface of a battery cell 400, including a skeleton 10 and a heat-absorbing material 20 (hydrogel). The skeleton 10 has holes 11 that penetrate the skeleton 10 along the thickness direction of the skeleton 10, and the heat-absorbing material 20 fills the holes 11.

[0078] Examples A2-A35

[0079] The embodiment is substantially the same as Example A1, except that at least one of the mass content of water in the endothermic material 20 (r), the density of the endothermic material 20 (ρ), the thickness of the endothermic composite material 100 (x), the area of ​​the first surface 101 (S), the ratio of the area of ​​the orthographic projection of the skeleton 10 on the first surface 101 to the area of ​​the first surface 101 (a), the number of layers of the sub-skeleton 10 in the skeleton 10 (n), and the thickness (x1) of the sub-skeleton 10 is different.

[0080] Comparative Examples A1-A9

[0081] The embodiment is substantially the same as Example A1, except that at least one of the mass content of water in the endothermic material 20 (r), the density of the endothermic material 20 (ρ), the thickness of the endothermic composite material 100 (x), the area of ​​the first surface 101 (S), the ratio of the area of ​​the orthographic projection of the skeleton 10 on the first surface 101 to the area of ​​the first surface 101 (a), the number of layers of the sub-skeleton 10 in the skeleton 10 (n), and the thickness (x1) of the sub-skeleton 10 is different.

[0082] Example B1

[0083] The heat absorbing composite material 100 in Example A1 was placed in the accommodation space of a packaging structure (made of aluminum-plastic film) with a thickness of 0.05 mm to obtain a heat absorbing element 300 .

[0084] Examples B2-B35

[0085] It is substantially the same as Example B1, except that the endothermic composite material 100 is replaced with the endothermic composite materials 100 in Examples A2-A35 in sequence.

[0086] Comparative Examples B1-B9

[0087] It is substantially the same as Example B1, except that the endothermic composite material 100 is replaced with the endothermic composite materials 100 in Comparative Examples A1-A9 in sequence.

[0088] Example C1

[0089] The heat sink 300 in Example B1 was placed between two identical battery cells 400 to produce a battery assembly 500 .

[0090] Examples C2-C35

[0091] It is substantially the same as Example C1, except that the heat absorbing element 300 is replaced with the heat absorbing elements 300 in Examples B2-B35 in sequence.

[0092] Comparative Examples C1-C9

[0093] It is substantially the same as Example C1, except that the heat absorbing element 300 is replaced with the heat absorbing elements 300 in Comparative Examples B1-B9 in sequence.

[0094] Performance testing

[0095] The mass content of water (r) in the endothermic material 20 in the endothermic composite material 100 in Examples A1-A35 and Comparative Examples A1-A9, the density of the endothermic material 20 (ρ), the thickness (x) of the endothermic composite material 100, the area of ​​the first surface 101 (S), the ratio of the area of ​​the orthographic projection of the skeleton 10 on the first surface 101 to the area of ​​the first surface 101 (a), the number of sub-skeleton layers in the skeleton 10 (n), and the thickness (x1) of the sub-skeleton were tested, and the value of a / S was calculated. The results are shown in Table 1.

[0096] The capacity (Q c ), specific heat capacity of battery cell 400 (c p ) and the mass (M) of the battery cell 400 were tested, and the results are shown in Table 2.

[0097] According to the data in Table 1 and Table 2, 2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M) is calculated as the result of Formula I; the value of n×x1 (i.e., the thickness H of the skeleton 10 in the endothermic composite material 100) is calculated as the result of Formula II; the value of r×(x×Sa×H) is calculated as the result of Formula III; the value of a×H / (x×S) is calculated as the result of Formula IV; the value of x / H is calculated as the result of Formula V; the volume energy density of the battery assembly 500 (Wh / L) = the number of cells 400 in the battery assembly 500 × the energy of a single cell 400 (W·h ) / volume of battery assembly 500 (L). Under the conditions of the same volume of battery assembly 500 and the capacity of single battery cell 400, the volume energy density of the battery assembly 500 in which only multiple battery cells 400 are arranged is w0, and the volume energy density of the battery assembly 500 in which battery cells 400 and endothermic composite material 100 are alternately arranged in the manner of Examples C1-C35 and Comparative Examples C1-C9 is w1. The degree of decrease in volume energy density ((w0-w1) / w0) is calculated, which is the result of Formula VI (retain three decimal places), and the results are shown in Table 3.

[0098] A needle penetration test was performed on one of the battery cells 400 in the battery assemblies 500 of Examples C1-C35 and Comparative Examples C1-C9 to detect whether thermal diffusion occurred in the other battery cell 400. The needle penetration test included the state of charge (SOC) of the battery cell 400 being 100%, the initial temperature of all the battery cells 400 in the battery assembly 500 being 45°C ± 2°C, and a 5mm straight steel needle was inserted into one of the battery cells 400 at a speed of 1mm / s until it ran away from the battery cell 400 and then stopped penetrating (thermal runaway of the battery cell 400 means that the explosion-proof valve of the battery cell 400 is opened, and The voltage of the battery cell 400 drops to less than 20% of the initial voltage), and then the battery cell 400 is pulled out after 2 minutes, with a maximum depth of 80 mm. The temperature of all battery cells 400 in the battery assembly 500 is continuously observed until it is less than 100°C. During this process, it is recorded whether thermal diffusion occurs in adjacent battery cells 400 (if the explosion-proof valves of adjacent battery cells 400 are open and the voltage of the battery cell 400 drops to less than 20% of the initial voltage, it is recorded as thermal diffusion). At the same time, the battery assembly 500 is disassembled to observe whether the heat-absorbing composite material 100 is damaged. The results are shown in Table 4.

[0099] Table 1 Test results of heat-absorbing composite materials

[0100] Table 2 Test results of battery cells

[0101] Table 3 Calculation results of formula

[0102] Table 4 Acupuncture results

[0103] From Table 3, the formula I(2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p×M)) results show that the results of the examples are all within the range of 0.2 to 30, while the results of the comparative examples are less than 0.2 or greater than 30. As can be seen from the needle penetration test in Table 4, after the needle penetration test, no thermal diffusion occurs in the battery assembly 500 provided by the example, the structure of the endothermic composite material 100 is intact and not damaged, the endothermic material 20 is not extruded, the endothermic composite material 100 has excellent mechanical properties, and the endothermic composite material 100 can still maintain its original endothermic performance. After the needle penetration test, thermal diffusion occurs in the battery assemblies 500 provided by comparative examples C1-C4 and C9, indicating that the endothermic composite materials 100 provided therein fail to perform a good heat absorption function and fail to prevent the occurrence of thermal diffusion, making them unusable. After the needle penetration test, although no thermal diffusion occurs in the battery assemblies 500 provided by comparative examples C5-C8, the packaging structure of the endothermic composite material 100 is destroyed and the endothermic composite material 100 is extruded, indicating that the mechanical properties of the endothermic composite material 100 are poor and cannot be used. Therefore, the heat-absorbing composite material 100 provided in the present application has excellent heat-absorbing performance and mechanical properties, and can be used in the battery assembly 500 to improve the performance of the battery assembly 500.

[0104] As can be seen from the results of Formula II (n×x1, i.e., H) in Table 3, compared to Examples C16, C30, and C35, the results of other Examples are all within the range of 0.05 to 5, allowing the endothermic composite material 100 to have both endothermic and mechanical properties, which is more conducive to its use.

[0105] From the results of Formula III (r×(x×Sa×H)) in Table 3, it can be seen that compared with Examples C11, C12, C16, C17, C28 and C29, the results of other examples are all greater than 11000, have better heat absorption effect, can be used in conjunction with high-capacity battery cells 400, and improve the performance of the battery cells 400; at the same time, Example C11 is roughly the same as Comparative Example C9, except that a larger capacity battery cell 400 is used in Comparative Example C9. It can be seen from the puncture test that heat diffusion occurs, which also shows that when the result of Formula III is greater than 11000, it can match the large-capacity battery cell 400, and that when the result of Formula III is less than or equal to 11000, it is suitable for the small-capacity battery cell 400.

[0106] The results of Formula IV (a×H / (x×S)) in Table 3 show that, compared to the results of other examples, the results of Examples C24 and C30 are both below 0.02. Furthermore, needle penetration tests show that when a×H / (x×S) is less than 0.02, although heat diffusion between adjacent battery cells 400 does not occur, the battery cells 400 expand and the volume of the skeleton 10 is too small. As a result, the battery cells 400 squeeze the heat sink 300, causing deformation. Specifically, the phase change material within the heat sink 300, squeezed by the batteries, diffuses outward into the gap between adjacent batteries, further deforming the heat sink 300. Deformation of the heat sink 300 refers to significant tensile deformation of the packaging film. Furthermore, when a×H / (x×S) is greater than 0.02, the heat sink 300 exhibits improved rigidity, facilitating its use in the battery assembly 500 and extending its service life.

[0107] As can be seen from the results of the formula V(x / H) in Table 3, compared to Comparative Examples C5-C8, the results of the embodiment and other comparative examples are all below 18. The endothermic composite material 100 has strong compression resistance and high mechanical properties, and is not damaged by the expansion force generated by the battery cell 400. The endothermic composite material 100 is structurally intact, and the endothermic material 20 is not squeezed out, resulting in high structural reliability and favorable use.

[0108] As can be seen from the results of Formula VI in Table 3, compared with Examples C22, C23, and C24, the results of other Examples are all below 0.2, indicating that the volume energy density of these Examples has a low degree of reduction. In other words, by placing the endothermic composite material 100 between adjacent battery cells 400, not only excellent heat absorption performance is achieved, but also the volume energy density of the entire battery assembly 500 can be guaranteed.

[0109] It can be seen from the x value in Table 1 that compared with Examples A22, A23, and A34, the thickness of the endothermic composite material 100 in other embodiments is relatively small, so that the volume proportion of the endothermic composite material 100 in the battery assembly 500 is relatively small, and the volume proportion of the battery cells 400 in the battery assembly 500 is increased, which is beneficial to improving the volume energy density of the battery assembly 500 and facilitating the use of the battery assembly 500.

[0110] The above is a preferred embodiment of the present application, but it should not be construed as limiting the scope of the present application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present application, and such improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A heat-absorbing composite material (100) for being arranged on the surface of a battery cell (400), wherein: The invention comprises a skeleton (10) and an endothermic material (20), wherein the endothermic material (20) comprises a phase change material, the skeleton (10) has a plurality of holes (11), and the holes (11) are filled with the endothermic material (20); along the thickness direction of the skeleton (10), the endothermic composite material (100) has a first surface (101) and a second surface (102) arranged opposite to each other, and the first surface (101) is located between the second surface (102) and the battery core (400). r, ρ, x, S, a, H, Q c 、c p The value of M satisfies: 0.2≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤30, Wherein, r is the mass content of the phase change material in the endothermic material (20), ρ is the density of the heat absorbing material (20), in kg / m 3 , x is the thickness of the heat-absorbing composite material (100), in mm, S is the area of ​​the first surface (101), in mm 2 , a is the area of ​​the orthographic projection of the skeleton (10) on the first surface (101), in mm 2 , H is the thickness of the skeleton (10), in mm, Q c is the capacity of the battery cell (400), in kJ, c p is the specific heat capacity of the battery cell (400), in kJ·kg -1 ·K -1 , M is the mass of the battery core (400), in kg.

2. The heat-absorbing composite material (100) according to claim 1, wherein r, p, x, S, a, H, and Q c 、the c p The value of M satisfies: 0.5≤2252×r×ρ(S×xa×H)×10 -9 / (0.6×Q c -360×c p ×M)≤15.

3. The heat-absorbing composite material (100) according to claim 1 or 2, wherein: The r is 80% to 99%, and / or The ρ is 900 kg / m 3 Up to 1200kg / m 3 .

4. The heat-absorbing composite material (100) according to any one of claims 1 to 3, wherein: The x is 0.35 mm to 7 mm, and / or The S is 5000mm 2 Up to 600,000 mm 2 , and / or The a is 500mm 2 Up to 270,000 mm 2 , and / or The H is 0.025 mm to 20 mm.

5. The heat-absorbing composite material (100) according to any one of claims 1 to 4, wherein: The Q c 576kJ to 3456kJ, The c p 0.8 kJ·kg -1 ·K -1 to 1.2 kJ·kg -1 ·K -1 , and / or The M is 1 kg to 5 kg.

6. The heat-absorbing composite material (100) according to any one of claims 1 to 5, wherein: The H is 0.05 mm to 5 mm; and / or, along the thickness direction of the skeleton (10), the skeleton (10) includes at least one layer of sub-skeleton, and the H satisfies H=n×x1, wherein n is the number of layers of the sub-skeleton in the heat-absorbing composite material (100), the n is an integer from 1 to 10, and x1 is the thickness of the sub-skeleton in mm, and the x1 is 0.025 mm to 2 mm.

7. The heat-absorbing composite material (100) according to any one of claims 1 to 6, wherein: The values ​​of S and a satisfy: 0.1≤a / S≤0.

45.

8. The heat-absorbing composite material (100) according to any one of claims 1 to 7, wherein: The values ​​of r, x, S, a, and H satisfy: r×(x×Sa×H)≥11000.

9. The heat-absorbing composite material (100) according to any one of claims 1 to 8, wherein: The values ​​of x, a, H, and S satisfy: a×H / (x×S)≥0.

02.

10. The heat-absorbing composite material (100) according to any one of claims 1 to 9, wherein: The values ​​of x and H satisfy: 1<x / H≤18.

11. The heat-absorbing composite material (100) according to any one of claims 1 to 10, wherein: The heat-absorbing material (20) comprises a matrix and the phase-change material, the matrix is ​​a hydrophilic polymer material, and the phase-change material in the heat-absorbing material (20) can be separated from the matrix when heated.

12. The heat-absorbing composite material (100) according to any one of claims 1 to 11, wherein: The heat-absorbing material (20) is a hydrogel.

13. The heat-absorbing composite material (100) according to any one of claims 1 to 12, wherein: The hole (11) penetrates the skeleton (10) along the thickness direction of the skeleton (10).

14. The heat-absorbing composite material (100) according to claim 13, wherein: The holes (11) uniformly penetrate the skeleton (10) along the thickness direction of the skeleton (10).

15. A heat absorbing element (300), wherein: The invention comprises a packaging structure and the heat-absorbing composite material according to any one of claims 1 to 14, wherein the packaging structure has an accommodating space inside, and the heat-absorbing composite material is arranged in the accommodating space.

16. A battery assembly (500), wherein: The battery assembly (500) comprises a battery core (400) and the heat absorbing member (300) according to claim 15, wherein the heat absorbing member (300) is arranged on a surface of the battery core (400); Or the battery assembly (500) comprises a battery core (400) and the endothermic composite material according to any one of claims 1 to 14, and the endothermic composite material is arranged on the surface of the battery core (400).

17. The battery assembly (500) according to claim 16, wherein: The battery cell (400) has a third surface, and the third surface is in contact with the first surface; wherein the surface area of ​​the third surface is greater than or equal to the surface area of ​​the first surface; and / or the projection of the first surface on the third surface is accommodated in the third surface; and / or the shape of the first surface is the same as the shape of the third surface.

18. An electrical device (600), wherein: Comprising the battery assembly (500) according to claim 16 or 17.

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