Battery module

Abstract

The application discloses a battery module, comprising a plurality of battery cells and at least one battery cell heat insulation assembly, the plurality of battery cells are arranged in sequence, and the battery cell heat insulation assembly is arranged between adjacent battery cells. Wherein, the battery cell heat insulation assembly comprises: a set of holding layers, which are oppositely arranged in the arrangement direction of the plurality of battery cells; and a heat insulation buffer layer, which is clamped between the set of holding layers to obtain the support of the set of holding layers. In the above manner, the application can improve the safety of the battery module, block heat diffusion and absorb expansion force, prolong the cycle life of the battery, and guarantee the integrity of the module structure.

Description

Technical Field

[0001] This application relates to the field of battery thermal insulation technology, and in particular to a battery module. Background Technology

[0002] In recent years, with the rapid development of new energy vehicles and energy storage industries, high-energy-density ternary lithium-ion batteries with square aluminum casings have become the mainstream choice in the market. In battery module design, to prevent thermal runaway and thermal diffusion, the thermal insulation materials used in related technologies have excellent high-temperature resistance and thermal insulation performance. However, the thermal insulation materials in related technologies often have obvious limitations—they are prone to compaction failure and loss of resilience under long-term pressure conditions.

[0003] As the number of battery cycles increases, the battery cells inevitably expand. If the thermal insulation material cannot continuously provide effective buffering, the internal stress of the module will accumulate, causing a sharp increase in the inter-cell compressive stress. This not only poses a risk of module structural deformation but may also seriously affect the safety performance and cycle life of the battery system. Utility Model Content

[0004] The main technical problem addressed by this application is to provide a cell heat insulation component that can improve the safety of the battery module. By blocking heat diffusion and absorbing expansion force, it can not only extend the battery cycle life but also ensure the integrity of the module structure.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is: This application provides a battery module, the battery module comprising: Multiple battery cells; and At least one cell insulation assembly, wherein the cell insulation assembly is located between adjacent cells and includes: A set of retaining layers are arranged opposite each other in the arrangement direction of the plurality of cells; A heat-insulating buffer layer is sandwiched between the set of retaining layers to obtain support for the set of retaining layers.

[0006] In one possible implementation, the retaining layer is made of a high-temperature resistant material that provides structural support, and / or the thermal insulation buffer layer is made of a material that has compressive resilience at room temperature and can be ceramicized at high temperatures.

[0007] In one possible implementation, the retaining layer is fiberglass cloth, mica paper, or high-temperature resistant inorganic fiber felt.

[0008] In one possible implementation, the heat insulation buffer layer is ceramicized silicone foam.

[0009] In one possible implementation, the thickness of the retaining layer is no greater than the thickness of the thermal insulation buffer layer.

[0010] In one possible implementation, the ratio of the thickness H1 of the retaining layer to the thickness H2 of the thermal insulation buffer layer satisfies: 1 / 60 ≤ H1 / H2 ≤ 1 / 15. The thickness H2 of the thermal insulation buffer layer can be in the millimeter range; for example, the thickness of the thermal insulation buffer layer is 1.5 mm to 3 mm, and / or the thickness of the retaining layer is 0.05 mm to 0.1 mm.

[0011] In one possible implementation, the area Sa of the side of the retaining layer facing the buffer layer is given by the ratio of the area Sb of the side of the buffer layer facing the retaining layer to the area Sa / Sb of the side of the buffer layer facing the retaining layer, satisfying the condition: 0.95 ≤ Sa / Sb ≤ 1.05.

[0012] In one possible implementation, the ratio of the area of ​​the side of the heat insulation buffer layer facing the battery cell to the area of ​​the side of the battery cell facing the heat insulation buffer layer is not less than 85%.

[0013] In one possible implementation, the battery cell has an electrode plate inside, and the battery cell has a main surface facing other battery cells. A first projection of the electrode plate on the main surface covers a second projection of the battery cell heat insulation assembly on the main surface, and the area of ​​the second projection is smaller than the area of ​​the first projection.

[0014] In one possible implementation, the main surface includes a first cell edge, a second cell edge, a third cell edge, and a fourth cell edge, wherein the first cell edge and the third cell edge are disposed opposite to each other in the length direction of the cell, and the second cell edge and the fourth cell edge are disposed opposite to each other in the width direction of the cell. The first projection has a first electrode sheet edge, a second electrode sheet edge, a third electrode sheet edge, and a fourth electrode sheet edge that correspond to the edges of the first battery cell edge, the second battery cell edge, the third battery cell edge, and the fourth battery cell edge, respectively; The second projection has a first heat-insulating edge, a second heat-insulating edge, a third heat-insulating edge, and a fourth heat-insulating edge, respectively corresponding to the edges of the first battery cell, the second battery cell, the third battery cell, and the fourth battery cell; The distance between the edge of the first battery cell and the first heat insulation edge, and the distance between the edge of the third battery cell and the third heat insulation edge are 10 mm-15 mm; the distance between the edge of the second battery cell and the second heat insulation edge, and the distance between the edge of the fourth battery cell and the fourth heat insulation edge are 5 mm-10 mm; the distance between the edge of the first electrode sheet and the first heat insulation edge, and the distance between the edge of the third electrode sheet and the third heat insulation edge are 4 mm-8 mm; the distance between the edge of the second electrode sheet and the second heat insulation edge, and the distance between the edge of the fourth electrode sheet and the fourth heat insulation edge are 3 mm-6 mm.

[0015] In one possible implementation, the main surface, the first projection, and the second projection are all rectangles, the edges of the first and third battery cells, the edges of the first and third electrode sheets, the first and third heat insulation edges are all the short sides of the corresponding rectangles, and the edges of the second and fourth battery cells, the edges of the second and fourth electrode sheets, the second and fourth heat insulation edges are all the long sides of the corresponding rectangles.

[0016] In one possible implementation, the thickness of the cell insulation component is 1.6-2.0 mm, and the cell insulation component is under 25-35% compression due to the pressure of adjacent cells.

[0017] In one possible implementation, the heat insulation buffer layer is a ceramicized silicone foam with a porous structure; the compression set of the heat insulation buffer layer is less than 5%; and after 5000 cycles of compression, the thickness retention rate of the heat insulation buffer layer is more than 95%. The ratio of the thermal conductivity tc1 of the heat insulation buffer layer before ceramization to the thermal conductivity tc2 of the heat insulation buffer layer after ceramization satisfies: 1.1≤tc1 / tc2≤1.3; The ratio of the hardness H1 of the heat insulation buffer layer before ceramization to the hardness H2 of the heat insulation buffer layer after ceramization satisfies: 3 / 8 ≤ H1 / H2 ≤ 2 / 3; The thermal insulation buffer layer has a thickness expansion rate of 3%-5% after ceramicization compared to its original thickness. Under 30% compression, the compressive stress of the heat insulation buffer layer before ceramization is 0.25 MPa-0.30 MPa, and the compressive stress of the heat insulation buffer layer after ceramization is 0.42 MPa-0.45 MPa; under 40% compression, the compressive stress of the heat insulation buffer layer before ceramization is 0.35 MPa-0.40 MPa, and the compressive stress of the heat insulation buffer layer after ceramization is 0.65 MPa-0.70 MPa; under 50% compression, the compressive stress of the heat insulation buffer layer before ceramization is 0.50 MPa-0.55 MPa, and the compressive stress of the heat insulation buffer layer after ceramization is 0.80 MPa-0.85 MPa.

[0018] In one possible implementation, the heat insulation buffer layer is ceramicized silicone foam, and the thickness of the ceramicized heat insulation buffer layer is 1.5 mm-3 mm. Under a 200°C hot-table test, at 200 s, the range of the reduction in back temperature of the heat insulation buffer layer after ceramization, K1, compared to before ceramization, is: 1 / 13 ≤ K1 ≤ 1 / 12; at 300 s, the range of the reduction in back temperature of the heat insulation buffer layer after ceramization, K2, is: 1 / 15 ≤ K2 ≤ 1 / 14; at 600 s, the range of the reduction in back temperature of the heat insulation buffer layer after ceramization, K3, is: 1 / 19 ≤ K3 ≤ 1 / 18. Under a 520°C hot-table test, at 200 s, the range of the reduction in back temperature K4 of the heat insulation buffer layer after ceramization compared to before ceramization is: 1 / 15 ≤ K4 ≤ 1 / 14; at 300 s, the range of the reduction in back temperature K5 of the heat insulation buffer layer after ceramization compared to before ceramization is: 1 / 18 ≤ K5 ≤ 1 / 17; at 600 s, the range of the reduction in back temperature K6 of the heat insulation buffer layer after ceramization compared to before ceramization is: 1 / 12 ≤ K6 ≤ 1 / 12.5.

[0019] In one possible implementation, the heat insulation buffer layer is ceramicized silicone foam with a porous structure; the compression permanent deformation rate of the battery cell heat insulation component is less than 3%; and after 5000 cycles of compression, the thickness retention rate of the battery cell heat insulation component is more than 96%. The heat insulation buffer layer is a ceramicized buffer material; Under 30% compression, the compressive stress of the battery cell heat insulation assembly before the heat insulation buffer layer is ceramicized is 0.35-0.4 MPa, and the compressive stress of the battery cell heat insulation assembly after the heat insulation buffer layer is ceramicized is 0.40-0.45 MPa; under 40% compression, the compressive stress of the battery cell heat insulation assembly before the heat insulation buffer layer is ceramicized is 0.40-0.45 MPa, and the compressive stress of the battery cell heat insulation assembly after the heat insulation buffer layer is ceramicized is 0.70-0.75 MPa; under 50% compression, the compressive stress of the battery cell heat insulation assembly before the heat insulation buffer layer is ceramicized is 0.55-0.60 MPa, and the compressive stress of the battery cell heat insulation assembly after the heat insulation buffer layer is ceramicized is 0.85-0.90 MPa.

[0020] In one possible implementation, the heat insulation buffer layer is ceramicized silicone foam, and the thickness of the ceramicized heat insulation buffer layer is 1.5 mm-3 mm; the ratio of the area of ​​the side of the heat insulation buffer layer facing the battery cell to the area of ​​the side of the battery cell facing the heat insulation buffer layer is not less than 85%. Under a 520°C hot test, at 200 s, the range of the reduction in back temperature of the battery cell thermal insulation component after the thermal insulation buffer layer is 1 / 29 ≤ K7 ≤ 1 / 27 compared to before ceramization; at 300 s, the range of the reduction in back temperature of the battery cell thermal insulation component after ceramization is 1 / 36 ≤ K8 ≤ 1 / 34; at 600 s, the range of the reduction in back temperature of the battery cell thermal insulation component after ceramization is 1 / 23 ≤ K9 ≤ 1 / 22.

[0021] In one possible implementation, the retaining layer is attached to the thermal insulation buffer layer, or the retaining layer and the thermal insulation buffer layer are connected by thermo-pressing.

[0022] In one possible implementation, it further includes: an adhesive layer located on the side of the retaining layer opposite to the heat insulation buffer layer, for bonding and fixing to the battery cell.

[0023] In one possible implementation, the material of the heat-insulating buffer layer is aerogel or phase change material.

[0024] In summary, the beneficial effects of this application are as follows: The battery module of this application includes a cell heat insulation component, which is disposed between adjacent cells. The cell heat insulation component includes a heat insulation buffer layer and a set of retaining layers. Since the heat insulation buffer layer has both heat insulation protection and buffering functions, it can effectively block heat transfer between cells, prevent the spread of thermal runaway, and prevent a chain reaction caused by thermal runaway of a single cell; it also has excellent buffering performance, which can absorb the expansion stress generated by the cells during charge and discharge cycles, avoiding damage to the module structure. The set of retaining layers is disposed opposite to each other in the arrangement direction of the multiple cells, and the set of retaining layers sandwiches the heat insulation buffer layer, which can provide fixed support for the entire cell heat insulation component and improve the stability of the cell heat insulation component. Through the above methods, the safety of the battery module can be significantly improved. By blocking heat diffusion and absorbing expansion force, not only can the battery cycle life be extended, but the integrity of the module structure can also be guaranteed. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the battery module structure in the embodiments of this application; Figure 2a This is one of the structural schematic diagrams of the cell heat insulation assembly in the embodiments of this application; Figure 2b This is the second schematic diagram of the structure of the cell heat insulation assembly in the embodiments of this application; Figure 2c This is the third structural schematic diagram of the cell heat insulation assembly in the embodiments of this application; Figure 3 This is the compressive stress-strain curve of a heat insulation buffer layer before and after ceramization in an embodiment of this application; Figure 4 These are the 200°C hot-stage test curves of a heat-insulating buffer layer before and after ceramization in the embodiments of this application; Figure 5 This is a 520°C hot-stage test curve of a heat insulation buffer layer before and after ceramization in an embodiment of this application; Figure 6a This is a schematic diagram showing the positional relationship between the heat insulation buffer layer and the battery cell in the embodiments of this application; Figure 6b This is a schematic diagram showing the positional relationship between the battery cell, electrode sheet, and battery cell heat insulation assembly in the embodiments of this application; Figure 6cThis is a schematic diagram showing the positional relationship between the battery cell, electrode sheet, and battery cell heat insulation assembly in the embodiments of this application; Figure 7 This is the compression strain cycle curve of a cell heat insulation component in an embodiment of this application before the heat insulation buffer layer is ceramicized; Figure 8 This is the compressive stress-strain curve of a cell heat insulation component in an embodiment of this application before the heat insulation buffer layer is ceramicized; Figure 9 This is a hot-stage test curve of a battery cell heat insulation component in an embodiment of this application before the heat insulation buffer layer is ceramicized at 520°C. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0027] Please see Figure 1 This application provides a battery module. The battery module may include multiple battery cells 100 and at least one battery cell heat insulation component 200. The multiple battery cells 100 are arranged sequentially in the same direction, and the battery cell heat insulation component 200 may be disposed between adjacent battery cells 100. This battery cell heat insulation component is a key functional component between adjacent battery cells in the battery module, playing a crucial role in ensuring the safety and reliability of the battery system and is an important guarantee for improving the overall performance of the power battery and energy storage system. This component is mainly applied to the spacing area between adjacent battery cells, achieving the protective function of the battery module through the material properties and specific structural design. Of course, it can also be used in other scenarios, such as being located between the battery cells and the battery module housing.

[0028] Understandably, the number of cell heat insulation components 200 in a battery module is designed according to the situation. Cell heat insulation components 200 can be set between all adjacent cells 100, or they can be set between some adjacent cells 100. For example, cell heat insulation components 200 can be set between cells in areas of greater stress in the battery module, while cell heat insulation components 200 can be omitted between cells in areas of less stress.

[0029] For the structure of the cell insulation assembly, please refer to [link / reference]. Figure 2a , Figure 2b as well as Figure 2c , Figure 2a , Figure 2b It's a different perspective. Figure 2c relatively Figure 2a , Figure 2b The difference lies in exposing the hierarchical structure of the battery cell insulation assembly as much as possible to facilitate a clearer understanding of the hierarchical structure within the battery cell insulation assembly. In one embodiment, the battery cell insulation assembly 200 includes a heat insulation buffer layer 20 and a set of retaining layers 30.

[0030] A set of retaining layers 30, arranged opposite each other, is used in a battery module. Specifically, the retaining layers 30 are arranged opposite each other in the direction of the arrangement of multiple battery cells. The purpose of the retaining layers 30 is to provide support, so they can be made of materials that are resistant to high temperatures and have structural support functions. It should be noted that the high temperature and room temperature mentioned in this article refer to the high temperature and room temperature in the battery field. For example, room temperature can be in the range of 25°C ± 3°C, while high temperature generally refers to a temperature greater than 35°C.

[0031] The heat insulation buffer layer 20 can be the core functional layer of the battery cell heat insulation assembly. Specifically, the heat insulation buffer layer 20 can be sandwiched between the set of retaining layers to obtain the support of the set of retaining layers. It should be noted that during the charging and discharging process of the battery module, in addition to the potential generation of a large amount of heat, the battery cells may expand and contract. For example, after a period of use, the battery cells may expand. Based on this, the heat insulation buffer layer 20 takes into account both heat insulation performance and elastic recovery characteristics. It can not only provide heat insulation for the battery cells in the battery module, but also provide a certain degree of resilience. During the entire life cycle of the battery, it absorbs the expansion force of the battery cells and buffers the pressure generated by the squeezing of the battery cells in the battery module. In addition, the heat insulation buffer layer 20 can also maintain a certain degree of structural integrity under high temperature conditions. Therefore, the purpose of the heat insulation buffer layer is heat insulation and buffering, so it can be made of a material that has compressive resilience at room temperature and can be ceramicized at high temperature. Ceramization refers to a phenomenon or process in the field of materials science, in which certain materials that were not originally ceramics (such as polymers, inorganic glasses, etc.) undergo changes in their internal structure under conditions such as high temperature, transforming into materials with ceramic properties.

[0032] Specifically, when the set of retaining layers are arranged opposite each other, a receiving space is formed between them. In the width direction of the receiving space (the width direction refers to the direction perpendicular to the depth direction, and the depth direction is consistent with the thickness direction of the retaining layer 30 and the heat insulation buffer layer 20), the heat insulation buffer layer 20 may partially extend beyond the receiving space, that is, the retaining layer 30 only partially covers the heat insulation buffer layer 20. However, in order to achieve complete protection of the heat insulation buffer layer 20, in some embodiments, the heat insulation buffer layer is completely contained in the receiving space, that is, the retaining layer 30 completely covers the heat insulation buffer layer 20. In this way, the heat insulation buffer layer 20 can either just fill the receiving space or partially fill it. For example, the projection of the heat insulation buffer layer 20 coincides with the projection of the retaining layer 30, that is, the outlines of the two projections are completely coincident, in which case the heat insulation buffer layer 20 just fills the receiving space; as another example, the projection of the heat insulation buffer layer 20 falls within the projection of the retaining layer 30, and the outlines of the two projections do not coincide, in which case the heat insulation buffer layer 20 partially fills the receiving space.

[0033] The projection mentioned in this article refers to the vertical projection on a horizontal plane. The horizontal plane is a plane perpendicular to the thickness direction of the retaining layer 30 and the heat insulation buffer layer 20, that is, a plane perpendicular to the arrangement direction of the multiple battery cells.

[0034] In one embodiment, when subjected to a specific temperature, the structure of the heat insulation buffer layer 20 is ceramicized, and the heat insulation capacity and structural strength increase sharply, thereby further preventing heat spread and diffusion between cells and preventing thermal runaway caused by the heat of adjacent cells; throughout the entire battery life cycle, it absorbs the expansion force of the cells, preventing the module from collapsing due to the destruction of the internal cell expansion force structure, significantly improving the battery cycle life and reducing the risk of module damage.

[0035] It is understood that the retaining layer 30 is divided into a first retaining layer and a second retaining layer on different sides of the heat insulation buffer layer 20, and the first retaining layer and the second retaining layer together constitute this set of retaining layers 30. The first retaining layer can be set to at least one layer, that is, it can be one, two, or more layers, without specific limitation here. Similarly, the second retaining layer can also be set to at least one layer, that is, it can be one, two, or more layers. The number of layers of the first retaining layer and the second retaining layer can be the same or different. The thickness of the first retaining layer and the second retaining layer can be the same or different. The specific materials of the first retaining layer and the second retaining layer can be the same or different.

[0036] In some embodiments, the retaining layer is attached to the heat insulation buffer layer, or the retaining layer and the heat insulation buffer layer are connected by thermocompression. For example, adhesive can be applied to both sides of the heat insulation buffer layer 20, and then the retaining layer 30 can be bonded to it to form the cell heat insulation assembly.

[0037] In some embodiments, reference Figure 2c The battery cell insulation assembly also includes an adhesive layer 10, located on the side of the retaining layer 30 facing away from the insulation buffer layer 20, for bonding and fixing to the battery cell. The adhesive layer 10 can specifically be double-sided tape or adhesive film, the purpose of which is to allow the entire battery cell insulation assembly to adhere to the surface of the battery cell. The adhesive layer 10 can completely cover the surface of the retaining layer 30 facing the battery cell, i.e., it can be fixed to the battery cell by full-surface adhesion; it can also partially cover the surface of the retaining layer 30 facing the battery cell, such as covering 1 / 3 or 1 / 2 of the surface of the retaining layer 30 facing the battery cell; or it can divide the retaining layer 30 into several independent strips and fix them to the battery cell simultaneously.

[0038] It is understood that adhesive layers 10 can be provided on both sides of the retaining layers 30 of the heat insulation buffer layer 20 (i.e., adhesive layers 10 are provided on both the first and second retaining layers), or adhesive layers 10 can be provided only on one side of the retaining layer 30 of the heat insulation buffer layer 20. That is, this application is not limited to single-sided adhesive; double-sided adhesive can also be used if the structure requires it.

[0039] In the above method, the cell heat insulation component is applied to the battery module and includes a heat insulation buffer layer 20 and a set of retaining layers 30. The heat insulation buffer layer 20 has both heat insulation and buffering functions, effectively blocking heat transfer between cells, preventing the spread of thermal runaway, and preventing a chain reaction caused by thermal runaway in a single cell; it also has excellent buffering performance, absorbing the expansion stress generated by the cells during charge and discharge cycles, preventing damage to the module structure. The set of retaining layers 30 is arranged opposite to each other, and the retaining layers 30 are connected and fixed to the cells. The set of retaining layers 30 clamps the heat insulation buffer layer 20 from both sides (after the cell heat insulation component is assembled into the battery module, the entire cell heat insulation component can be in a compressed state), providing fixed support for the entire cell heat insulation component and improving its stability. Through this method, the safety of the battery module can be significantly improved. By blocking heat diffusion and absorbing expansion forces, not only can the battery cycle life be extended, but the integrity of the module structure can also be guaranteed.

[0040] In one embodiment, the ratio of the thermal conductivity tc01 of the retaining layer to the thermal conductivity tc02 (before ceramization) of the thermal insulation buffer layer satisfies: 0.4 ≤ tc01 / tc02 ≤ 0.6. For example, tc01 / tc02 can be, but is not limited to, 0.4, 0.5, 0.6, etc.

[0041] In one embodiment, the thickness of the retaining layer 30 is no greater than the thickness of the thermal insulation buffer layer 20. On one hand, the thermal insulation buffer layer 20 primarily aims to prevent heat propagation and diffusion between battery cells. When one battery cell experiences thermal runaway due to an abnormal condition, it prevents adjacent cells from experiencing thermal runaway. The thickness of this layer needs to balance thermal insulation and cost. On the other hand, the retaining layer 30 mainly functions as a wall or outer shell to ensure structural integrity and prevent the thermal insulation system from collapsing when the internal heat-resistant insulation material is threatened by high-temperature impact. Given a fixed overall thickness, this layer should not be too thick, as excessive thickness increases cost and weakens the inner layer's thermal insulation capability. Considering both aspects, the thickness of the retaining layer 30 is no greater than the thickness of the thermal insulation buffer layer 20.

[0042] In one embodiment, the ratio of the thickness H1 of the retaining layer to the thickness H2 of the heat insulation buffer layer satisfies: 1 / 60 ≤ H1 / H2 ≤ 1 / 15. For example, H1 / H2 can be, but is not limited to, 1 / 60, 1 / 50, 1 / 40, 1 / 30, 1 / 20, or 1 / 15.

[0043] The thickness H2 of the heat insulation buffer layer can be in the millimeter range. In one embodiment, the thickness of the heat insulation buffer layer 20 can be 1.5 mm to 3 mm, for example, but not limited to 1.5 mm, 2 mm, 2.5 mm, and 3 mm. The thickness of the heat insulation buffer layer 20 can be adjusted according to the requirements of cell size, cell heat insulation components, and battery module design, and is not limited here.

[0044] In one embodiment, the thickness of the retaining layer 30 can be controlled within the range of 0.05 mm to 0.1 mm, such as, but not limited to, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, and 0.1 mm. This thickness design can ensure the necessary structural support strength while minimizing the problem of increased cost or impact on the thermal insulation performance of the inner layer due to excessive thickness.

[0045] In one embodiment, the area Sa of the side of the retaining layer facing the buffer layer and the area Sb of the side of the buffer layer facing the retaining layer satisfy the following ratio: 0.95 ≤ Sa / Sb ≤ 1.05. For example, Sa / Sb can be, but is not limited to, 0.95, 0.98, 1, 1.02, or 1.05.

[0046] In one embodiment, the heat insulation buffer layer 20 is made of silicone foam material, specifically ceramicized heat insulation buffer material, such as ceramicized silicone foam.

[0047] Ceramicized silicone foam exhibits excellent compression resilience at room temperature, enabling it to continuously absorb the expansion force of the battery cells during battery cycle charging and discharging, preventing stress concentration within the battery module and thus slowing down the degradation of battery cycle life. Simultaneously, the material's high resilience prevents deformation or damage to the battery cell insulation components due to long-term stress, improving the overall structural stability of the battery cell insulation components.

[0048] When a battery experiences thermal runaway, the ceramicized silicone foam undergoes a ceramic transformation at high temperatures (approximately 600°C), forming a dense ceramic layer. This significantly reduces its thermal conductivity, greatly improving its insulation performance and effectively preventing heat transfer to adjacent cells. Furthermore, the increased hardness of the ceramicized material maintains the structural integrity of the cell insulation component, preventing collapse or heat propagation caused by thermal runaway, thereby enhancing the safety performance of the battery system.

[0049] In one embodiment, the thermal insulation buffer layer 20 can be made of silicone material. Si-O bonds have stronger bond energy and are more stable than C-C bonds; they also have a wider operating temperature range: -60°C to 250°C. Silicone materials transform from a rubbery state to an inorganic ceramic state at high temperatures, providing support to the battery cell in the thickness direction. This prevents the material from losing its support strength, causing structural collapse and loss of thermal barrier properties. After ceramicization, the thickness expands, resulting in volume expansion and a longer heat conduction path, thus improving the thermal insulation performance by approximately 5% or more compared to before ceramicization.

[0050] Specifically, the heat insulation buffer layer 20 is made of silicone rubber raw rubber as the base material, and its main components are silica-derived organosilicon polymers, including hydroxyl-terminated polysiloxanes or vinyl silicone oils, foaming agents, fillers, vulcanization accelerators, such as hydrogen-containing silicone oils or alkoxysilanes.

[0051] Specifically, before ceramization, the compression set of the heat insulation buffer layer 20 is <5%, such as 4.5%, 4.3%, 4.1%, etc. Relevant tests were conducted according to the national standard GB / T 6669-2008. The heat insulation buffer layer 20 sample was compressed to 50% using a fixture and placed in a 70°C oven for 72 hours, then allowed to recover at room temperature for 30 minutes. The compression set of the sample was then calculated.

[0052] Furthermore, before ceramization, after 5000 cycles of cyclic compression, the compressed thickness of the heat insulation buffer layer 20 is more than 95% of its original thickness, such as 96%, 97%, or 98%. It should be noted that the original thickness is the thickness of the heat insulation buffer layer 20 in its natural state before the cyclic compression test, and the compressed thickness is the thickness of the heat insulation buffer layer 20 in its natural state after the cyclic compression test. This compression thickness retention rate is obtained by performing 5000 compression-release cycles of 0-50% strain in the thickness direction on a sample of the heat insulation buffer layer 20. The specific operation is as follows: Prepare a sample of the heat insulation buffer layer 20 with thickness *a*. Using a cyclic compression test device, apply a certain stress to the sample and compress it to a thickness of 0.5a at 50% (i.e., 0.5a). Then release the stress until the sample recovers its compression. This constitutes one compression cycle. Perform 5000 compression cycles in this manner, then measure the thickness *b* of the sample and calculate the thickness retention rate = *b / a*100% > 95%.

[0053] In other words, the thermal insulation buffer layer 20 in this embodiment has excellent compressive resilience before ceramization. Thus, when applied to the cell thermal insulation assembly of this application, it can effectively absorb the mechanical stress generated by the cyclic expansion of the cell, thereby providing a durable and stable support for the cell.

[0054] Furthermore, under a 30% compression, the compressive stress generated by the unceramified heat insulation buffer layer 20 is 0.25 MPa-0.30 MPa, and the compressive stress generated by the ceramified heat insulation buffer layer 20 is 0.42 MPa-0.45 MPa. Under a 40% compression, the compressive stress generated by the unceramified heat insulation buffer layer 20 is 0.35 MPa-0.40 MPa, and the compressive stress generated by the ceramified heat insulation buffer layer 20 is 0.65 MPa-0.70 MPa. Under a 50% compression, the compressive stress generated by the unceramified heat insulation buffer layer 20 is 0.50 MPa-0.55 MPa, and the compressive stress generated by the ceramified heat insulation buffer layer 20 is 0.80 MPa-0.85 MPa. The relevant data are based on GB / T 18942.1-2003.

[0055] It can be seen that, when the thickness is compressed by the same proportion, the stress required by the ceramicized heat insulation buffer layer 20 is significantly greater than that required by the unceramized heat insulation buffer layer 20. In other words, after ceramicization, the mechanical strength of the heat insulation buffer layer 20, such as its compressive strength, is significantly enhanced.

[0056] Specifically, in one application example, the compressive stress-strain curves of the thermal insulation buffer layer 20 before and after ceramization are as follows: Figure 3As shown, it should be noted that the compressive stress-strain curve was obtained based on GB / T 18942.1-2003. The figure shows that, overall, the compressive stress of the thermal insulation buffer layer 20 after ceramization (up to 0.83 MPa) is significantly higher than before ceramization (up to 0.52 MPa), indicating that ceramization significantly improves the compressive stress level of the thermal insulation buffer layer 20. The reason for the lower stress at the initial strain-to-stress ratio after ceramization is that the surface of the material after ceramization is undulating, resulting in a relatively small initial contact area, leading to lower stress at the same strain. However, as the strain increases and the contact conditions change, the stress growth accelerates and surpasses that before ceramization.

[0057] In other words, the buffer insulation layer 20 undergoes a ceramic transformation under the high-temperature environment triggered by thermal runaway, fundamentally altering its compressive stress-strain curve characteristics and significantly increasing its compressive stress. This indicates that the buffer insulation layer 20 forms a rigid ceramic body with higher mechanical strength at high temperatures. Thus, the sharp increase in modulus after ceramicization allows the buffer insulation layer 20 to mechanically resist the violent expansion and jet impact generated by the thermal runaway battery cell, physically preventing adjacent battery cells from being ignited, effectively delaying or preventing heat propagation. The porous ceramic layer formed after ceramicization has extremely low thermal conductivity, forming a stable thermal barrier and significantly slowing down the rate of heat transfer to adjacent battery cells.

[0058] In some embodiments, the ratio of the hardness H1 of the heat insulation buffer layer before ceramization to the hardness H2 of the heat insulation buffer layer after ceramization satisfies: 3 / 8 ≤ H1 / H2 ≤ 2 / 3. For example, H1 / H2 can be, but is not limited to, 3 / 8, 1 / 2, 2 / 3, etc.

[0059] Furthermore, the Shore hardness of the heat insulation buffer layer 20 before ceramization is 15 Shore-20 Shore, specifically 15 Shore A, 18 Shore A, 20 Shore A, etc.; the Shore hardness after ceramization is 30 Shore-40 Shore, specifically 30 Shore A, 35 Shore A, 40 Shore A, etc.

[0060] The hardness test was based on GB / T531.1-2008.

[0061] The ratio of the thermal conductivity tc1 of the heat insulation buffer layer before ceramization to the thermal conductivity tc2 of the heat insulation buffer layer after ceramization satisfies: 1.1 ≤ tc1 / tc2 ≤ 1.3. For example, tc1 / tc2 can be, but is not limited to, 1.1, 1.2, 1.3, etc.

[0062] The thermal conductivity test was conducted based on GB / T 32064-2015.

[0063] After ceramization, the thickness increases by approximately 3%-5% compared to before ceramization, meaning the thickness expansion rate is 3%-5%, specifically 3%, 4%, 5%, etc. This thickness expansion rate can be measured and calculated using calipers. In a specific application example, the thermal insulation buffer layer 20 expands from 2 mm before ceramization to 2.1 mm after ceramization.

[0064] The changes in hardness and thickness before and after ceramization indicate that the hardness of the ceramized heat insulation buffer layer 20 is enhanced and the thickness is increased to a certain extent compared with that before ceramization. Thus, the heat insulation buffer layer 20 can not only form a hard barrier that is not easily penetrated, but also extend the heat conduction path, thereby enhancing the overall heat insulation capability of the battery cell heat insulation component.

[0065] Under a 200°C hot-table test, at 200 s, the range of the reduction in back temperature of the thermal insulation buffer layer after ceramization, K1, compared to before ceramization, is: 1 / 13 ≤ K1 ≤ 1 / 12; at 300 s, the range of the reduction in back temperature of the thermal insulation buffer layer after ceramization, K2, is: 1 / 15 ≤ K2 ≤ 1 / 14; at 600 s, the range of the reduction in back temperature of the thermal insulation buffer layer after ceramization, K3, is: 1 / 19 ≤ K3 ≤ 1 / 18.

[0066] K1 is, for example, but not limited to, 1 / 13, 1 / 12.5, 1 / 12, etc. K2 is, for example, but not limited to, 1 / 15, 1 / 14.5, 1 / 14, and K3 is, for example, but not limited to, 1 / 19, 1 / 18.5, 1 / 18.

[0067] The percentage reduction in back temperature is calculated by subtracting the back temperature measured after ceramization from the back temperature measured before ceramization, and then dividing the difference by the back temperature measured before ceramization. For example, if the back temperature measured before ceramization is 50°C and the back temperature measured after ceramization is 45°C, then the percentage reduction in back temperature is (50-45) / 50.

[0068] Under a 200°C hot-table test, the back temperature in a 100-second period is typically tens of degrees Celsius. For example, under a 200°C hot-table test, at 100 seconds, the back temperature of the pre-ceramicized heat insulation buffer layer 20 is 44°C-50°C, and after ceramicization, it is 40°C-45°C; at 200 seconds, the back temperature of the pre-ceramicized heat insulation buffer layer 20 is 60°C-65°C, and after ceramicization, it is 55°C-60°C; at 300 seconds, the back temperature of the pre-ceramicized heat insulation buffer layer 20 is 70°C-75°C, and after ceramicization, it is 65°C-70°C; at 400 seconds… At 500 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 80°C-85°C, and after ceramization, it was 75°C-80°C; at 500 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 85°C-90°C, and after ceramization, it was 80°C-85°C; at 600 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 90°C-95°C, and after ceramization, it was 85°C-90°C. These results were obtained from a 200°C hot-stage test on the heat insulation buffer layer 20 before and after ceramization.

[0069] Furthermore, under a 520°C hot-stage test, at 200 s, the range of the reduction in back temperature of the thermal insulation buffer layer after ceramization (K4) compared to before ceramization is: 1 / 15 ≤ K4 ≤ 1 / 14; at 300 s, the range of the reduction in back temperature of the thermal insulation buffer layer after ceramization (K5) compared to before ceramization is: 1 / 18 ≤ K5 ≤ 1 / 17; at 600 s, the range of the reduction in back temperature of the thermal insulation buffer layer after ceramization (K6) compared to before ceramization is: 1 / 12 ≤ K6 ≤ 1 / 12.5.

[0070] K4 is, for example, but not limited to, 1 / 15, 1 / 14.5, 1 / 14, etc. K5 is, for example, but not limited to, 1 / 18, 1 / 17.5, 1 / 17, and K6 is, for example, but not limited to, 1 / 12, 1 / 12.55, 1 / 12.5.

[0071] Under a 520°C hot-table test, the back temperature typically ranges from several hundred degrees Celsius over a hundred seconds. For example, under a 520°C hot-table test, at 100 seconds, the back temperature of the pre-ceramicized insulation buffer layer 20 is 90-100°C, and after ceramicization, it is 80-90°C; at 200 seconds, the back temperature is 140-150°C, and after ceramicization, it is 130-140°C; at 300 seconds, the back temperature is 170-180°C, and after ceramicization, it is 160-170°C; at 400 seconds… At 500 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 190°C-200°C, and after ceramization, it was 170°C-180°C. At 500 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 210°C-220°C, and after ceramization, it was 200°C-210°C. At 600 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 230°C-240°C, and after ceramization, it was 210°C-220°C. These results were obtained from a 520°C hot-stage test on the heat insulation buffer layer 20 before and after ceramization.

[0072] The hot test method is as follows: A stable heat source of 200°C or 520°C is applied to the lower surface (hot surface) of a sample with a thickness of 1.8mm and a heat insulation buffer layer 20 of 100*100mm. Then, a pressure of 20kPa is applied to the upper surface (back side or cold surface) of the sample, and a temperature sensor is placed to monitor the temperature change of this surface over time.

[0073] Specifically, in one application example, the thermal insulation buffer layer 20 was subjected to hot-stage tests at 200°C and 520°C after pre-ceramization, and the hot-stage test diagrams are as follows: Figure 4 and Figure 5 As shown. The specific hot-platform testing method is the same as the aforementioned hot-platform testing method, and will not be repeated here. From Figure 4 and Figure 5 As can be seen from the data, in the 200°C hot stage test, the cold surface temperature of the pre-ceramicized heat insulation buffer layer 20 did not exceed 91°C after 10 minutes, and the cold surface temperature of the post-ceramicized heat insulation buffer layer 20 did not exceed 85°C after 10 minutes; in the 520°C hot stage test, the cold surface temperature of the pre-ceramicized heat insulation buffer layer 20 did not exceed 232°C after 10 minutes, and the cold surface temperature of the post-ceramicized heat insulation buffer layer 20 did not exceed 219°C after 10 minutes.

[0074] In other words, the thermal insulation buffer layer 20 exhibits superior thermal insulation capabilities both before and after ceramization, with further enhancement after ceramization. Specifically, in this embodiment, the ceramized thermal insulation buffer layer 20 forms a microporous ceramic layer during the ceramization process, effectively enhancing the material's thermal resistance and slowing down the rate of heat transfer to the back side. This performance optimization is crucial for battery thermal runaway protection: when adjacent cells experience thermal runaway and high-temperature emissions, this material not only maintains structural integrity through ceramization (as mentioned earlier regarding increased strength), but also actively improves its thermal insulation performance, providing a longer buffer against temperature rise for the protected cells, thereby effectively extending the trigger time for thermal propagation and enhancing the overall safety of the battery system.

[0075] Specifically, the heat insulation buffer layer 20 can be processed into sheet, strip, or irregular structure to adapt to the layout requirements of different battery modules.

[0076] In one embodiment, the ratio of the area of ​​the heat insulation buffer layer 20 to the area of ​​the battery cell is not less than 85%. Specifically, the area of ​​the heat insulation buffer layer 20 can refer to the area of ​​the side of the heat insulation buffer layer 20 facing the battery cell, and the area of ​​the battery cell can refer to the area of ​​the side of the battery cell facing the heat insulation buffer layer 20. Please refer to [link to relevant documentation]. Figure 6a In one embodiment, the two cells adjacent to the cell insulation assembly include a first cell 41 and a second cell 42. The insulation buffer layer 20 includes two outer surfaces 55 that are disposed opposite to each other and face the adjacent cells respectively. Each cell includes a main surface 50 facing other cells. Of course, each cell 100 may have two main surfaces 50 disposed opposite to each other. Specifically, the main surface 50 may refer to the surface with the largest area among all the outer surfaces of the cell 100, specifically the surface facing other cells 100 (such as facing adjacent cells 100) or the adjacent cell insulation assembly 200, such as the side of the cell 100 facing the insulation buffer layer 20 in the above embodiment. The area ratio here may refer to the ratio of the area of ​​the main surface 50 to the area of ​​the outer surface 55; it may also be the ratio of the area of ​​the projection of the main surface 50 and the outer surface 55 onto a horizontal plane. The horizontal plane refers to a plane perpendicular to the thickness direction of the retaining layer 30 and the insulation buffer layer 20, that is, a plane perpendicular to the arrangement direction of the multiple cells.

[0077] In this way, the heat insulation effect of the heat insulation buffer layer 20 can be improved. The ratio of the area of ​​the heat insulation buffer layer 20 to the area of ​​the battery cell can be, for example, but not limited to, 85%, 86%, 88%, 90%, or 92%. In practical applications, this area ratio can be adjusted based on factors such as the required heat insulation effect and cost, and is not limited here.

[0078] This embodiment optimizes the material selection and structural design of the thermal insulation buffer layer 20, thereby improving battery cycle life, enhancing module mechanical stability, and effectively suppressing thermal runaway propagation, achieving synergistic optimization of battery safety and performance.

[0079] Further, please refer to Figure 6b and Figure 6c In one embodiment, the battery cell 100 in the battery module has an electrode sheet 101 inside.

[0080] The first projection 60 of the electrode sheet 101 on the main surface 50 covers the second projection 70 of the cell heat insulation assembly 200 on the main surface 50, and the area of ​​the second projection 70 is smaller than the area of ​​the first projection 60. Herein, the first projection 60 and the second projection 70 refer to the perpendicular projections of the electrode sheet 101 and the cell heat insulation assembly 200 on the main surface 50, that is, the orthographic projections.

[0081] In this embodiment, the main surface 50 has a first cell edge 51, a second cell edge 52, a third cell edge 53, and a fourth cell edge 54 connected in sequence. The first cell edge 51 and the third cell edge 53 are arranged opposite each other in the length direction of the cell 100, and the second cell edge 52 and the fourth cell edge 54 are arranged opposite each other in the width direction of the cell 100. The cell 100 has mutually perpendicular length, width, and thickness directions. The length and width directions of the cell 100 correspond to the length and width directions of the main surface 50, respectively, and the thickness direction is consistent with the arrangement direction of the multiple cells 100.

[0082] The battery cell 100 includes an electrode sheet 101. The electrode sheet forms a first projection 60 on the main surface 50 of the battery cell. The first projection 60 has a first electrode sheet edge 61, a second electrode sheet edge 62, a third electrode sheet edge 63, and a fourth electrode sheet edge 64 that are sequentially connected and correspond to the first battery cell edge 51, the second battery cell edge 52, the third battery cell edge 53, and the fourth battery cell edge 54, respectively. The first electrode sheet edge 61 is arranged opposite to the third electrode sheet edge 63, and the second electrode sheet edge 62 and the fourth electrode sheet edge 64 are arranged opposite to each other.

[0083] The cell heat insulation assembly 200 forms a second projection 70 on the main surface 50 of the cell. The second projection 70 has a first heat insulation edge 71, a second heat insulation edge 72, a third heat insulation edge 73, and a fourth heat insulation edge 74 that are sequentially connected and correspond to the first cell edge 51, the second cell edge 52, the third cell edge 53, and the fourth cell edge 54, respectively. The first heat insulation edge 71 is arranged opposite to the third heat insulation edge 73, and the second heat insulation edge 72 and the fourth heat insulation edge 74 are arranged opposite to each other.

[0084] In this embodiment, the distance D1 between the first cell edge 51 and the first heat insulation edge 71, and the distance D3 between the third cell edge 53 and the third heat insulation edge 73 are 10 mm-15 mm, specifically 10 mm, 12 mm, 14 mm, 15 mm, etc.; the distance D2 between the second cell edge 52 and the second heat insulation edge 72, and the distance D4 between the fourth cell edge 54 and the fourth heat insulation edge 74 are 5 mm-10 mm, specifically 5 mm, 6 mm, 8 mm, 10 mm, etc. The distance d1 between the first electrode edge 61 and the first heat insulation edge 71, and the distance d3 between the third electrode edge 63 and the third heat insulation edge 73 are 4 mm-8 mm, specifically 4 mm, 5 mm, 6 mm, 8 mm, etc.; the distance d2 between the second electrode edge 62 and the second heat insulation edge 72, and the distance d4 between the fourth electrode edge 64 and the fourth heat insulation edge 74 are 3 mm-6 mm, specifically 3 mm, 4 mm, 5 mm, 6 mm, etc.

[0085] In one embodiment, the main surface 50, the first projection 60, and the second projection 70 of the battery cell can all be rectangles. Of course, the rectangle referred to here can be a strict rectangle or a rectangle-like rectangle, such as a rectangle with chamfered corners (e.g., rounded corners), or a rectangle with dimensions within the tolerance range. The first battery cell edge 51 and the third battery cell edge 53, the first electrode sheet edge 61 and the third electrode sheet edge 63, and the first heat insulation edge 71 and the third heat insulation edge 73 are all the shorter sides of the corresponding rectangles, while the second battery cell edge 52 and the fourth battery cell edge 54, the second electrode sheet edge 62 and the fourth electrode sheet edge 64, and the second heat insulation edge 72 and the fourth heat insulation edge 74 are all the longer sides of the corresponding rectangles.

[0086] In one embodiment, the material of the heat insulation buffer layer 20 can be ceramicized silicone foam, aerogel material, or other heat-resistant insulation materials (phase change materials). Specifically, the aerogel material can be pre-oxidized fiber aerogel, glass fiber aerogel, ceramic fiber aerogel, etc., and other heat-resistant insulation materials can be phase change materials.

[0087] Furthermore, the aforementioned materials can be used individually or in combination. For example, ceramicized silicone foam can be used in the main stress-bearing areas between battery cells to provide cushioning, while an aerogel layer can be superimposed in heat-sensitive areas to enhance thermal insulation. Specific material selection and optimization can be based on requirements such as cell expansion stress absorption, cycle life improvement, and the thermal safety performance of the battery module; no limitations are imposed here.

[0088] In one embodiment, the retaining layer 30 can be made of various high-temperature resistant materials, including but not limited to fiberglass cloth, mica paper, or high-temperature resistant felt. Among them, fiberglass cloth has excellent mechanical strength and high-temperature resistance, and can withstand working environments above 500°C for a long time; mica paper has good insulation properties and heat resistance, and can maintain structural stability under high temperature conditions above 600°C; high-temperature resistant felt, such as ceramic fiber felt, combines flexibility and heat insulation properties.

[0089] In terms of specific structure, the retaining layer 30 can be attached to both sides of the insulation material to form a sandwich-like composite structure by double-sided attachment; or the retaining layer 30 can be completely covered by the insulation buffer layer 20 by hot pressing process.

[0090] By incorporating this retaining layer 30, when the internal thermal insulation material, i.e., the thermal insulation buffer layer 20, is subjected to high-temperature impact, the retaining layer 30 acts as a rigid support to prevent the entire thermal insulation system from collapsing. Furthermore, in extreme cases of battery thermal runaway (such as temperatures exceeding 600°C), the retaining layer 30 can work synergistically with the ceramicized thermal insulation buffer layer 20 to form a stable thermal barrier. Thus, it ensures both the structural stability of the battery module under normal operating conditions and provides reliable safety protection in the event of thermal runaway.

[0091] Based on the above structure, the battery cell heat insulation assembly 200 of this application includes the aforementioned heat insulation buffer layer 20, and a set of retaining layers 30 located on both sides of the heat insulation buffer layer 20 and covering the heat insulation buffer layer 20. The heat insulation buffer layer 20 is made of ceramicized heat insulation buffer material, such as ceramicized silicone foam, while the retaining layers 30 are made of high-temperature resistant materials, such as fiberglass cloth, mica paper, or high-temperature resistant felt cloth. Based on this structure and material composition, the battery cell heat insulation assembly 200 has excellent heat insulation protection and buffering functions.

[0092] Specifically, before the thermal insulation buffer layer 20 is ceramized, the compression set of the cell thermal insulation component 200 is 1-3%. The relevant tests were conducted according to the national standard GB / T 6669-2008. The cell thermal insulation component 200 sample was compressed to 50% using a fixture and placed in a 70°C oven for 72 hours, then allowed to recover at room temperature for 30 minutes. The compression set of the sample was then calculated.

[0093] Furthermore, before the thermal insulation buffer layer 20 is ceramized, the battery cell thermal insulation component 200 undergoes 5000 cycles of cyclic compression, resulting in a compressed thickness of 96%-99% of its original thickness. It should be noted that the original thickness refers to the thickness of the battery cell thermal insulation component 200 in its natural state before the cyclic compression test, while the compressed thickness refers to the thickness of the battery cell thermal insulation component 200 in its natural state after the cyclic compression test. This compression thickness retention rate is obtained by performing 5000 compression-release cycles of 0-50% strain in the thickness direction on a sample of the battery cell thermal insulation component 200. The specific operation is as follows: Prepare a sample of the battery cell thermal insulation component 200 with thickness 'a'. Using a cyclic compression test device, apply a certain stress to the sample and compress it to a thickness of 0.5a at 50% (i.e., 0.5a). Then release the stress until the sample recovers its compression. This constitutes one compression cycle. Perform 5000 compression cycles in this manner, then measure the thickness 'b' of the sample and calculate the thickness retention rate = b / a * 100%.

[0094] In other words, the cell insulation component 200 in this embodiment has excellent compressibility before ceramicization, which can effectively absorb the mechanical stress generated by the cyclic expansion of the cell, thereby providing a long-lasting and stable support for the cell.

[0095] In a specific application scenario, the compressive strain cycle curve of the battery cell thermal insulation component 200 before the thermal insulation buffer layer 20 is exemplified as follows: Figure 7 As shown, it should be noted that the compressive stress-strain cycle curve was obtained based on GB 7757-2009. The figure shows that before the thermal insulation buffer layer 20 is ceramized, the strain curves of the cell thermal insulation component 200 after compressive stress release almost overlap, further demonstrating its excellent compressive resilience and high stability before the thermal insulation buffer layer 20 is ceramized, which is beneficial for extending the cell cycle life in this application.

[0096] Furthermore, under a 30% compression, the compressive stress generated by the pre-ceramicized cell thermal insulation component 200 is 0.35-0.4 MPa, and the compressive stress generated by the post-ceramicized cell thermal insulation component 200 is 0.40-0.45 MPa; under a 40% compression, the compressive stress generated by the pre-ceramicized cell thermal insulation component 200 is 0.40-0.45 MPa, and the compressive stress generated by the post-ceramicized cell thermal insulation component 200 is 0.70-0.75 MPa; under a 50% compression, the compressive stress generated by the pre-ceramicized cell thermal insulation component 200 is 0.55-0.60 MPa, and the compressive stress generated by the post-ceramicized cell thermal insulation component 200 is 0.85-0.90 MPa. The relevant data are based on GB / T 18942.1-2003.

[0097] It can be seen that, under the same compression ratio, the stress required by the cell heat insulation component 200 after the heat insulation buffer layer 20 is ceramicized is significantly greater than the stress required by the cell heat insulation component 200 before the heat insulation buffer layer 20 is ceramicized. In other words, after ceramicization, the mechanical strength of the cell heat insulation component 200, such as its compressive strength, is significantly enhanced.

[0098] Specifically, in one application example, the compressive stress-strain curve of the cell insulation assembly 200 before the insulation buffer layer 20 is ceramized is as follows: Figure 8 As shown, it should be noted that the compressive stress-strain curve is obtained based on GB / T 18942.1-2003. The compressive stress of the cell thermal insulation component 200 after the thermal insulation buffer layer 20 is ceramized is significantly higher than that before ceramization, because the thermal insulation buffer layer 20 can significantly improve the compressive stress level of the cell thermal insulation component 200 after ceramization.

[0099] Under a 520°C hot test, at 200 s, the range of the reduction in back temperature K7 of the cell heat insulation component 200 after the heat insulation buffer layer is 1 / 29 ≤ K7 ≤ 1 / 27 compared to before ceramization; at 300 s, the range of the reduction in back temperature K8 of the cell heat insulation component 200 after ceramization is 1 / 36 ≤ K8 ≤ 1 / 34; at 600 s, the range of the reduction in back temperature K9 of the cell heat insulation component 200 after ceramization is 1 / 23 ≤ K9 ≤ 1 / 22.

[0100] K7 is, for example, but not limited to, 1 / 29, 1 / 28, 1 / 27, etc. K8 is, for example, but not limited to, 1 / 36, 1 / 35, 1 / 34, etc., and K9 is, for example, but not limited to, 1 / 23, 1 / 22.5, 1 / 22.

[0101] Under a 520°C hot test, the back temperature in a 100-second period is typically several hundred degrees Celsius. For example, under a 520°C hot test, after 200 seconds, the back temperature of the cell insulation component 200 before the thermal insulation buffer layer 20 is 135°C-145°C, and after the thermal insulation buffer layer 20 is ceramicized, the back temperature of the cell insulation component 200 is 130°C-140°C; after 300 seconds, the back temperature of the cell insulation component 200 before ceramicization is 170°C-180°C, and after ceramicization, the back temperature of the cell insulation component 200 is 165°C-175°C; after 600 seconds, the back temperature of the cell insulation component 200 before ceramicization is 220°C-230°C, and after ceramicization, the back temperature of the cell insulation component 200 is 210°C-220°C. The above results are obtained from 520°C hot-stage tests on the cell thermal insulation component 200 before and after ceramicization of the thermal insulation buffer layer 20. The specific hot-stage test method is as follows: A stable heat source of 520°C is applied to the lower surface (hot surface) of a 100*100mm sample of the cell thermal insulation component 200 with a thickness of 1.8mm. Then, a pressure of 20kPa is applied to the upper surface (back surface or cold surface) of the sample, while a temperature sensor is placed to monitor the temperature change of this surface over time.

[0102] Specifically, in one application example, the cell insulation assembly 200 undergoes a hot-stage test at 520°C after the insulation buffer layer 20 is pre-ceramized, and the hot-stage test results are shown in the figure below. Figure 9 As shown. The specific hot-table test method is the same as the aforementioned hot-table test method, and will not be repeated here.

[0103] from Figure 9 As can be seen from the 520°C hot-stage test, the cold surface temperature of the battery cell insulation component 200, both before and after ceramization of the heat insulation buffer layer 20, did not exceed 230°C after 10 minutes, and the cold surface temperature of the battery cell insulation component 200 was even lower after ceramization. In other words, the battery cell insulation component 200 exhibits superior heat insulation capabilities both before and after ceramization of the heat insulation buffer layer 20, and the heat insulation capability is further improved after ceramization.

[0104] In other words, the cell insulation component of this application has excellent compression resilience, mechanical strength and temperature insulation properties, which can extend the battery cycle life and ensure the integrity of the module structure by blocking heat diffusion and absorbing expansion force.

[0105] In summary, in the cell heat insulation assembly 200 of the battery module in this embodiment, the heat insulation buffer layer has both heat insulation and buffering functions. It can effectively block heat transfer between cells 100, prevent the spread of thermal runaway, and prevent a chain reaction caused by thermal runaway of a single cell 100. It also has excellent buffering performance, which can absorb the expansion stress generated by the cells 100 during charge and discharge cycles, avoiding damage to the module structure. A set of retaining layers sandwiching the heat insulation layer can provide fixed support for the entire cell heat insulation assembly 200, improving the stability of the cell heat insulation assembly 200. Through the above methods, the safety of the battery module can be significantly improved. By blocking heat diffusion and absorbing expansion force, not only can the battery cycle life be extended, but the integrity of the module structure can also be guaranteed.

[0106] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A battery module, characterized in that, The battery module includes: Multiple battery cells; and At least one cell insulation assembly, wherein the cell insulation assembly is located between adjacent cells and includes: A set of retaining layers are arranged opposite each other in the arrangement direction of the plurality of cells; A heat-insulating buffer layer is sandwiched between the set of retaining layers to obtain support for the set of retaining layers.

2. The battery module according to claim 1, characterized in that, The retaining layer is made of a high-temperature resistant material that provides structural support; and / or, The heat insulation buffer layer is made of a material that has compressive resilience at room temperature and can be ceramicized at high temperature.

3. The battery module according to claim 1, characterized in that, The ratio of the thermal conductivity tc01 of the retaining layer to the thermal conductivity tc02 of the thermal insulation buffer layer satisfies: 0.4≤tc01 / tc02≤0.

6.

4. The battery module according to any one of claims 1-3, characterized in that, The retaining layer is made of fiberglass cloth, mica paper, or high-temperature resistant inorganic fiber felt.

5. The battery module according to any one of claims 1-3, characterized in that, The heat insulation buffer layer is ceramicized silicone foam.

6. The battery module according to claim 1, characterized in that, The thickness of the retaining layer is not greater than the thickness of the heat insulation buffer layer.

7. The battery module according to claim 6, characterized in that, The ratio of the thickness H1 of the retaining layer to the thickness H2 of the heat insulation buffer layer satisfies: 1 / 60 ≤ H1 / H2 ≤ 1 / 15.

8. The battery module according to claim 1, characterized in that, The ratio of the area Sa of the side of the retaining layer facing the buffer layer to the area Sb of the side of the buffer layer facing the retaining layer satisfies: 0.95≤Sa / Sb≤1.

05.

9. The battery module according to claim 1, characterized in that, The ratio of the area of ​​the side of the heat insulation buffer layer facing the battery cell to the area of ​​the side of the battery cell facing the heat insulation buffer layer is not less than 85%.

10. The battery module according to claim 1, characterized in that, The battery cell has an electrode plate inside, and the battery cell has a main surface facing other battery cells. The first projection of the electrode plate on the main surface covers the second projection of the battery cell heat insulation assembly on the main surface, and the area of ​​the second projection is smaller than the area of ​​the first projection.

11. The battery module according to claim 10, characterized in that, The main surface includes a first cell edge, a second cell edge, a third cell edge, and a fourth cell edge, wherein the first cell edge and the third cell edge are disposed opposite to each other in the length direction of the cell, and the second cell edge and the fourth cell edge are disposed opposite to each other in the width direction of the cell; The first projection has a first electrode sheet edge, a second electrode sheet edge, a third electrode sheet edge, and a fourth electrode sheet edge that correspond to the edges of the first battery cell edge, the second battery cell edge, the third battery cell edge, and the fourth battery cell edge, respectively; The second projection has a first heat-insulating edge, a second heat-insulating edge, a third heat-insulating edge, and a fourth heat-insulating edge, respectively corresponding to the edges of the first battery cell, the second battery cell, the third battery cell, and the fourth battery cell; The distance between the edge of the first battery cell and the first heat insulation edge, and the distance between the edge of the third battery cell and the third heat insulation edge are 10 mm-15 mm; the distance between the edge of the second battery cell and the second heat insulation edge, and the distance between the edge of the fourth battery cell and the fourth heat insulation edge are 5 mm-10 mm; the distance between the edge of the first electrode sheet and the first heat insulation edge, and the distance between the edge of the third electrode sheet and the third heat insulation edge are 4 mm-8 mm; the distance between the edge of the second electrode sheet and the second heat insulation edge, and the distance between the edge of the fourth electrode sheet and the fourth heat insulation edge are 3 mm-6 mm.

12. The battery module according to claim 11, characterized in that, The main surface, the first projection, and the second projection are all rectangles. The edges of the first and third battery cells, the first and third electrode sheets, the first and third heat insulation edges are all the short sides of the corresponding rectangles. The edges of the second and fourth battery cells, the second and fourth electrode sheets, the second and fourth heat insulation edges are all the long sides of the corresponding rectangles.

13. The battery module according to claim 1, characterized in that, The thickness of the cell insulation component is 1.6-2.0 mm, and the cell insulation component is under 25-35% compression due to the pressure of the adjacent cells.

14. The battery module according to claim 1, characterized in that, The heat insulation buffer layer is ceramicized silicone foam, which has a porous structure; the compression permanent deformation rate of the heat insulation buffer layer is less than 5%; and after 5000 cycles of compression, the thickness retention rate of the heat insulation buffer layer is more than 95%. The ratio of the thermal conductivity tc1 of the heat insulation buffer layer before ceramization to the thermal conductivity tc2 of the heat insulation buffer layer after ceramization satisfies: 1.1≤tc1 / tc2≤1.3; The ratio of the hardness H1 of the heat insulation buffer layer before ceramization to the hardness H2 of the heat insulation buffer layer after ceramization satisfies: 3 / 8 ≤ H1 / H2 ≤ 2 / 3; The thermal insulation buffer layer has a thickness expansion rate of 3%-5% after ceramicization compared to its original thickness. Under 30% compression, the compressive stress of the heat insulation buffer layer before ceramization is 0.25 MPa-0.30 MPa, and the compressive stress of the heat insulation buffer layer after ceramization is 0.42 MPa-0.45 MPa; under 40% compression, the compressive stress of the heat insulation buffer layer before ceramization is 0.35 MPa-0.40 MPa, and the compressive stress of the heat insulation buffer layer after ceramization is 0.65 MPa-0.70 MPa; under 50% compression, the compressive stress of the heat insulation buffer layer before ceramization is 0.50 MPa-0.55 MPa, and the compressive stress of the heat insulation buffer layer after ceramization is 0.80 MPa-0.85 MPa.

15. The battery module according to claim 1, characterized in that, The heat insulation buffer layer is ceramicized silicone foam, and the thickness of the heat insulation buffer layer is 1.5 mm-3 mm; Under a 200°C hot-table test, at 200 s, the range of the reduction in back temperature of the heat insulation buffer layer after ceramization, K1, compared to before ceramization, is: 1 / 13 ≤ K1 ≤ 1 / 12; at 300 s, the range of the reduction in back temperature of the heat insulation buffer layer after ceramization, K2, is: 1 / 15 ≤ K2 ≤ 1 / 14; at 600 s, the range of the reduction in back temperature of the heat insulation buffer layer after ceramization, K3, is: 1 / 19 ≤ K3 ≤ 1 / 18. Under a 520°C hot-table test, at 200 s, the ratio of the reduction in back temperature of the heat insulation buffer layer after ceramization to before ceramization, K4, is in the range of 1 / 15 ≤ K4 ≤ 1 / 14; at 300 s, the ratio of the reduction in back temperature of the heat insulation buffer layer after ceramization, K5, is in the range of 1 / 18 ≤ K5 ≤ 1 / 17; at 600 s, the ratio of the reduction in back temperature of the heat insulation buffer layer after ceramization, K6, is in the range of 1 / 12 ≤ K6 ≤ 1 / 12.

5.

16. The battery module according to claim 1, characterized in that, The heat insulation buffer layer is ceramicized silicone foam, which has a porous structure; the compression permanent deformation rate of the battery cell heat insulation component is less than 3%; and after 5000 cycles of compression, the thickness retention rate of the battery cell heat insulation component is more than 96%. The heat insulation buffer layer is a ceramicized buffer material; Under 30% compression, the compressive stress of the battery cell heat insulation assembly before the heat insulation buffer layer is ceramicized is 0.35-0.4 MPa, and the compressive stress of the battery cell heat insulation assembly after the heat insulation buffer layer is ceramicized is 0.40-0.45 MPa; under 40% compression, the compressive stress of the battery cell heat insulation assembly before the heat insulation buffer layer is ceramicized is 0.40-0.45 MPa, and the compressive stress of the battery cell heat insulation assembly after the heat insulation buffer layer is ceramicized is 0.70-0.75 MPa; under 50% compression, the compressive stress of the battery cell heat insulation assembly before the heat insulation buffer layer is ceramicized is 0.55-0.60 MPa, and the compressive stress of the battery cell heat insulation assembly after the heat insulation buffer layer is ceramicized is 0.85-0.90 MPa.

17. The battery module according to claim 1, characterized in that, The heat insulation buffer layer is ceramicized silicone foam, and the thickness of the ceramicized heat insulation buffer layer is 1.5 mm-3 mm; the ratio of the area of ​​the side of the heat insulation buffer layer facing the battery cell to the area of ​​the side of the battery cell facing the heat insulation buffer layer is not less than 85%. Under a 520°C hot-stage test, at 200 s, the range of the reduction in back temperature of the battery cell thermal insulation component after the thermal insulation buffer layer was 1 / 29 ≤ K7 ≤ 1 / 27 compared to before ceramization; at 300 s, the range of the reduction in back temperature of the battery cell thermal insulation component after the thermal insulation buffer layer was 1 / 36 ≤ K8 ≤ 1 / 34; at 600 s, the range of the reduction in back temperature of the battery cell thermal insulation component after the thermal insulation buffer layer was 1 / 23 ≤ K9 ≤ 1 / 22.

18. The battery module according to claim 1, characterized in that, The retaining layer is attached to the heat insulation buffer layer, or the retaining layer and the heat insulation buffer layer are connected by heat pressing.

19. The battery module according to claim 1, characterized in that, Also includes: An adhesive layer, located on the side of the retaining layer opposite to the heat insulation buffer layer, is used to bond and fix the battery cell.

20. The battery module according to claim 1, characterized in that, The material of the heat insulation buffer layer is aerogel or phase change material.

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