Battery module

Abstract

The application discloses a battery module. The battery module comprises a plurality of battery cells and at least one battery cell heat insulation assembly. The battery cell heat insulation assembly is located between adjacent battery cells and comprises a fixing member, a heat insulation buffer layer and at least one retaining layer. The fixing member defines an accommodation space. The heat insulation buffer layer is arranged in the accommodation space. The at least one retaining layer is arranged on one side of the fixing member and the heat insulation buffer layer and covers the fixing member and the heat insulation buffer layer. In this way, the battery module has high safety, can block heat diffusion and absorb expansion force, can prolong the cycle life of the battery, and can 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 battery module with high safety. 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 address the aforementioned technical problems, this application provides a battery module comprising multiple battery cells and at least one battery cell heat insulation component. The heat insulation component is located between adjacent battery cells and includes a fixing member, a heat insulation buffer layer, and at least one retaining layer. The fixing member defines a receiving space. The heat insulation buffer layer is disposed within the receiving space. At least one retaining layer is disposed on one side of the fixing member and the heat insulation buffer layer, and covers the fixing member and the heat insulation buffer layer.

[0006] The thickness of the heat insulation buffer layer shall not exceed the thickness of the fastener.

[0007] The adjacent battery cells include a first battery cell and a second battery cell. The heat insulation buffer layer includes a first outer surface and a second outer surface arranged opposite to each other, with the first outer surface facing the first battery cell and the second outer surface facing the second battery cell. The fastener includes a third outer surface and a fourth outer surface arranged opposite to each other, with the third outer surface facing the first battery cell and the fourth outer surface facing the second battery cell. The first outer surface is located on the side of the third outer surface away from the first battery cell, and the second outer surface is located on the side of the fourth outer surface away from the second battery cell.

[0008] 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 shall not be less than 85%.

[0009] The battery cell has an electrode plate inside and 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 component on the main surface, and the area of ​​the second projection is smaller than the area of ​​the first projection.

[0010] The main surface includes interconnected first, second, third, and fourth battery cell edges. The first and third battery cell edges are positioned opposite each other along the length of the battery cell, while the second and fourth battery cell edges are positioned opposite each other along the width of the battery cell. A first projection has first, second, third, and fourth electrode sheet edges corresponding to the first, second, third, and fourth battery cell edges, respectively. A second projection has first, second, third, and fourth heat-insulating edges corresponding to the first, second, third, and fourth battery cell edges, respectively. The spacing between the first and first heat-insulating edges and between the third and third battery cell edges is 10 mm-15 mm; the spacing between the second and second heat-insulating edges and between the fourth and fourth battery cell edges is 5 mm-10 mm; and the spacing between the first and first electrode sheet edges and between the third and third heat-insulating edges is 4 mm-8 mm. The distance between the edge of the second electrode and the edge of the second heat insulation layer and the distance between the edge of the fourth electrode and the edge of the fourth heat insulation layer are 3 mm to 6 mm.

[0011] Among them, the main surface, the first projection and the second projection are all rectangles, the edges of the first battery cell and the third battery cell, the edges of the first electrode sheet and the third electrode sheet, and the edges of the first heat insulation edge and the third heat insulation edge are all the short sides of the corresponding rectangles, and the edges of the second battery cell and the fourth battery cell, the edges of the second electrode sheet and the fourth electrode sheet, and the edges of the second heat insulation edge and the fourth heat insulation edge are all the long sides of the corresponding rectangles.

[0012] The thickness of the heat insulation buffer layer is 1.5 mm-3 mm.

[0013] The thermal insulation buffer layer is made of ceramicized silicone foam, which has a porous structure. Before ceramicization, the compression set of the thermal insulation buffer layer is less than 5%. After 5000 cycles of compression, the thickness retention rate of the thermal insulation buffer layer is over 95%. Before ceramicization, the hardness of the thermal insulation buffer layer is 15 Shore A-20 Shore A; after ceramicization, the hardness is 30 Shore A-40 Shore A. The thickness expansion rate of the thermal insulation buffer layer after ceramicization is 3%-5% compared to before ceramicization. Under 30% compression, the compressive stress generated by the thermal insulation buffer layer before ceramicization is 0.25 MPa-0.30 MPa, and the compressive stress generated by the thermal insulation buffer layer after ceramicization is 0.42 MPa-0.45 MPa. Under 40% compression, the compressive stress generated by the thermal insulation buffer layer before ceramicization is 0.35 MPa-0.40 MPa, and the compressive stress generated by the thermal insulation buffer layer after ceramicization is 0.65 MPa-0.70 MPa. MPa; Under 50% compression, the compressive stress generated by the heat insulation buffer layer before ceramization is 0.50 MPa-0.55 MPa, and the compressive stress generated by the heat insulation buffer layer after ceramization is 0.80 MPa-0.85 MPa.

[0014] The heat insulation buffer layer is made of ceramicized silicone foam, with a thickness of 1.5 mm-3 mm. Under a 200℃ hot bench test, the back temperature of the heat insulation buffer layer before ceramicization was 60℃-65℃ after 200 seconds, and 55℃-60℃ after ceramicization; after 300 seconds, the back temperature was 70℃-75℃ after ceramicization, and 65℃-70℃ after ceramicization; after 600 seconds, the back temperature was 90℃-95℃ after ceramicization, and 85℃-90℃ after ceramicization; under a 520℃ hot bench test, the back temperature of the heat insulation buffer layer before ceramicization was 140℃-150℃ after 200 seconds, and 130℃-140℃ after ceramicization; after 300 seconds... At 600s, the back temperature of the heat insulation buffer layer before ceramization was 170℃-180℃, and the back temperature of the heat insulation buffer layer after ceramization was 160℃-170℃; at 600s, the back temperature of the heat insulation buffer layer before ceramization was 230℃-240℃, and the back temperature of the heat insulation buffer layer after ceramization was 210℃-220℃.

[0015] The thickness of the fastener is 1.5 mm to 3 mm.

[0016] The fastener has a frame structure, and the accommodating space extends through the frame structure along the arrangement direction of the multiple battery cells.

[0017] The thickness of the retaining layer is 0.05 mm to 0.1 mm.

[0018] The thermal insulation buffer layer is made of ceramicized silicone foam, which has a porous structure. The compression set of the battery cell thermal insulation component is 2%-4%. After 5000 cycles of compression, the thickness retention rate of the battery cell thermal insulation component is 95%-98%. Under 30% compression, the compressive stress generated by the battery cell thermal insulation component before ceramicization of the thermal insulation buffer layer is 0.20 MPa-0.25 MPa, and after ceramicization, it is 0.30 MPa-0.35 MPa. Under 40% compression, the compressive stress generated by the battery cell thermal insulation component before ceramicization is 0.30 MPa-0.35 MPa, and after ceramicization, it is 0.40 MPa-0.45 MPa. Under 50% compression, the compressive stress generated by the battery cell thermal insulation component before ceramicization is 0.45 MPa-0.50 MPa. The compressive stress generated by the cell insulation component after the insulation buffer layer is ceramicized is 0.60 MPa-0.65 MPa.

[0019] The heat insulation buffer layer is made of ceramicized silicone foam, with a thickness of 1.5 mm to 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℃ hot test, the back temperature of the battery cell heat insulation component before the heat insulation buffer layer is ceramicized is 140℃-150℃ after 200s, and 135℃-145℃ after the heat insulation buffer layer is ceramicized; the back temperature of the battery cell heat insulation component before the heat insulation buffer layer is ceramicized is 170℃-180℃ after 300s, and 165℃-175℃ after the heat insulation buffer layer is ceramicized; the back temperature of the battery cell heat insulation component before the heat insulation buffer layer is ceramicized is 215℃-225℃ after 600s, and 210℃-220℃ after the heat insulation buffer layer is ceramicized.

[0020] The beneficial effects of this application are as follows: Unlike existing technologies, the battery module of this application includes multiple battery cells and at least one battery cell heat insulation component, which is located between adjacent battery cells. The battery cell heat insulation component includes a fixing member, a heat insulation buffer layer, and at least one retaining layer. The fixing member defines a receiving space, the heat insulation buffer layer is disposed within the receiving space, and at least one retaining layer is disposed on one side of the fixing member and the heat insulation buffer layer, covering both the fixing member and the heat insulation buffer layer. The fixing member can limit the position of the heat insulation buffer layer and control the spacing between battery cells, ensuring the battery cells are grouped together. The heat insulation buffer layer has both heat insulation and buffering functions, effectively blocking heat transfer between battery cells, preventing the spread of thermal runaway, and preventing a chain reaction caused by thermal runaway in a single battery cell; it also has excellent buffering performance, absorbing the expansion stress generated by the battery cells during charge and discharge cycles, preventing damage to the module structure; the retaining layer covers the fixing member and the heat insulation layer, providing fixed support for the entire battery cell heat insulation component and improving its stability. The above methods can significantly improve the safety of battery modules. 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. Attached Figure Description

[0021] 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 2 This is a schematic diagram of the structure of the cell heat insulation assembly in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the fastener and the heat insulation buffer layer in the embodiment of this application; Figure 4 This is the compressive stress-strain curve of a heat insulation buffer layer before and after ceramization in an embodiment of this application; Figure 5 These are the 200°C hot-stage test curves of a heat-insulating buffer layer in the embodiments of this application before and after ceramization; Figure 6 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 7 This is a schematic diagram showing the positional relationship between the fastener, the heat insulation buffer layer, and the battery cell in the embodiments of this application; Figure 8 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 9 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 10 This is the compression strain cycle curve of a cell heat insulation component in an embodiment of this application before and after the heat insulation buffer layer is ceramicized; Figure 11 This is a compressive stress-strain curve of a cell heat insulation component in an embodiment of this application before and after the heat insulation buffer layer is ceramicized; Figure 12 This is a 520°C hot-stage test curve of a cell heat insulation component in an embodiment of this application before and after the heat insulation buffer layer is ceramicized. Detailed Implementation

[0022] 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.

[0023] Please see Figure 1 This application provides a battery module. The battery module may include multiple battery cells 100 and at least one cell heat insulation component 200. Specifically, the cell heat insulation component 200 can be disposed between adjacent battery cells 100. It is a key functional component between adjacent 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. The cell heat insulation component 200 is mainly applied to the spacing area between adjacent battery cells 100, 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 cell 100 and the battery module housing.

[0024] Please see Figure 2-3 In one embodiment, the cell heat insulation assembly 200 includes a fixing member 10, a heat insulation buffer layer 20, and a retaining layer 30.

[0025] Furthermore, the fixing member 10 may be defined with a receiving space, which may be a receiving space that extends through both sides along the arrangement direction between adjacent cells 100, or a receiving space that extends through one side along that direction, or a receiving space formed inside the fixing member 10, without limitation here.

[0026] The heat insulation buffer layer 20 can be the core functional layer of the cell heat insulation assembly 200, and can be specifically set within the accommodating space. It should be noted that during the charging and discharging process of the battery module, in addition to potentially generating a large amount of heat, the cell 100 may expand and contract. Furthermore, after a period of use, the cell 100 may expand. Based on this, the heat insulation buffer layer 20 combines heat insulation performance and elastic recovery characteristics, not only providing temperature-resistant heat insulation for the cell 100 in the battery module, but also providing a certain degree of resilience. Throughout the battery's lifespan, it absorbs the expansion force of the cell and buffers the pressure generated by the squeezing of the cell 100 within the battery module; moreover, the heat insulation buffer layer 20 can maintain a certain degree of structural integrity under high-temperature conditions.

[0027] Specifically, the heat insulation buffer layer 20 can either completely fill the receiving space of the fastener 10 or partially fill the receiving space.

[0028] 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 the cells 100 and preventing thermal runaway of adjacent cells 100; throughout the battery's entire life cycle, it absorbs the expansion force of the cells 100, preventing the module from being damaged and collapsing due to the expansion force of the internal cells 100, significantly improving the battery's cycle life and reducing the risk of module damage.

[0029] The retaining layer 30 can be configured as at least one layer, that is, it can be one, two, or more layers, without specific limitation here. When the retaining layer 30 is one layer, it can be disposed on one side of the fixing member 10 and the heat insulation buffer layer 20, specifically on the side of the fixing member 10 and the heat insulation buffer layer 20 facing an adjacent cell 100; when the retaining layer 30 is two layers, it can be disposed on both sides of the fixing member 10 and the heat insulation buffer layer 20, specifically, one retaining layer 30 is located on the side of the fixing member 10 and the heat insulation buffer layer 20 facing an adjacent cell 100, and the other retaining layer 30 is located on the side of the fixing member 10 and the heat insulation buffer layer 20 facing another adjacent cell 100; of course, the two retaining layers 30 can also be disposed adjacently, that is, stacked on the same side of the fixing member 10 and the heat insulation buffer layer 20. When the retaining layer 30 is multi-layered, the multi-layered retaining layer 30 can be stacked on top of each other and disposed on the same side of the fixing member 10 and the heat insulation buffer layer 20 facing the same battery cell 100, or it can be partially located on the side of the fixing member 10 and the heat insulation buffer layer 20 facing an adjacent battery cell 100, and partially located on the side of the fixing member 10 and the heat insulation buffer layer 20 facing another adjacent battery cell 100. No specific limitation is made here.

[0030] Furthermore, the retaining layer 30 is provided to cover the fastener 10 and the heat insulation buffer layer 20. Specifically, the retaining layer 30 may completely cover the fastener 10 and the heat insulation buffer layer 20 on one side, or it may partially cover the fastener 10 and the heat insulation buffer layer 20, for example, covering a part of the fastener 10 and a part of the heat insulation buffer layer 20, or covering a part of the fastener 10 and the entire heat insulation buffer layer 20, or covering the entire fastener 10 and a part of the heat insulation buffer layer 20, or covering the entire fastener 10 and the entire heat insulation buffer layer 20.

[0031] Specifically, the retaining layer 30 can be connected to the fixing member 10 and / or the heat insulation buffer layer 20 by means of adhesive bonding, hot pressing, etc. For example, the heat insulation buffer layer 20 can be embedded in the receiving space of the fixing member 10 first, then adhesive can be applied to the surface of the fixing member 10, and then the retaining layer 30 can be bonded to it to form the cell heat insulation assembly 200.

[0032] In the above-described battery module embodiment, the cell heat insulation assembly 200 between adjacent cells 100 includes a fixing member 10, a heat insulation buffer layer 20, and at least one retaining layer 30. The fixing member 10 defines a receiving space, the heat insulation buffer layer 20 is disposed within the receiving space, and at least one retaining layer 30 is disposed on one side of the fixing member 10 and the heat insulation buffer layer 20, covering both the fixing member 10 and the heat insulation buffer layer 20. The fixing member 10 can limit the position of the heat insulation buffer layer 20, control the spacing between adjacent cells 100, and ensure the cells 100 are grouped together. The heat insulation buffer layer 20 combines heat insulation and buffering functions. It effectively blocks heat transfer between cells 100, prevents the spread of thermal runaway, and prevents a chain reaction caused by thermal runaway in a single cell 100. It also has excellent buffering performance, absorbing the expansion stress generated by the cells 100 during charge-discharge cycles, thus preventing damage to the module structure. The retaining layer 30 covers the fixing component 10 and the heat insulation layer, providing fixed support for the entire cell heat insulation assembly 200 and improving its stability. Through these methods, 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.

[0033] In one embodiment, the thickness of the heat insulation buffer layer 20 is not greater than the thickness of the fastener 10.

[0034] As mentioned earlier, the heat insulation buffer layer 20 has a heat-resistant and heat-insulating function. However, if it is frequently and significantly compressed during use, its thickness may change, which may impair the heat insulation performance of the heat insulation buffer layer 20 to some extent, resulting in a decrease in its heat insulation capacity. In this embodiment, the thickness of the heat insulation buffer layer 20 is no greater than the thickness of the fixing member 10. Therefore, during charging and discharging, if the battery cell 100 expands, it will preferentially apply pressure to the fixing member 10 or simultaneously to the fixing member 10 and the heat insulation buffer layer 20, so that the fixing member 10 can withstand a certain amount of pressure, thereby reducing the probability that the heat insulation buffer layer 20 will be damaged due to frequent compression.

[0035] 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, 3 mm. The thickness of the heat insulation buffer layer 20 can be adjusted according to the size of the cell 100, the cell heat insulation component 200 and the battery module design requirements, etc., and is not limited here.

[0036] 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.

[0037] Ceramicized silicone foam exhibits excellent compression resilience at room temperature, enabling it to continuously absorb the expansion force of the battery cell 100 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 the battery cell heat insulation component 200 from deforming or being damaged due to long-term stress, improving the overall structural stability of the battery cell heat insulation component 200.

[0038] When thermal runaway occurs in the battery, 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 and greatly improves its insulation performance, effectively preventing heat transfer to adjacent cells. Furthermore, the increased hardness of the ceramicized material maintains the structural integrity of the cell insulation component 200, preventing collapse or heat propagation caused by thermal runaway, thereby enhancing the safety performance of the battery system.

[0039] 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℃ to 250℃. Silicone material transforms from a rubbery state to an inorganic ceramic state at high temperatures, providing support for the cell 100 in the thickness direction. This prevents the material from losing its support strength, causing structural collapse and loss of thermal barrier performance. 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.

[0040] 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.

[0041] 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℃ oven for 72 hours, then allowed to recover at room temperature for 30 minutes. The compression set of the sample was then calculated.

[0042] 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%.

[0043] 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 200 of this application, it can effectively absorb the mechanical stress generated by the cyclic expansion of the cell 100, thereby providing a durable and stable support for the cell 100.

[0044] 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.

[0045] 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.

[0046] 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 4 As 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.

[0047] 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 thermally runaway battery cell 100, physically preventing adjacent battery cells 100 from being detonated, 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 100.

[0048] 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. This hardness test is based on GB / T531.1-2008.

[0049] 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.

[0050] The changes in hardness and thickness before and after ceramicization indicate that the hardness of the ceramicized heat insulation buffer layer 20 is enhanced and the thickness is increased to a certain extent compared with that before ceramicization. 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 200.

[0051] Furthermore, under a 200℃ hot test, at 100 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 44℃-50℃, and the back temperature of the post-ceramicized heat insulation buffer layer 20 was 40℃-45℃; at 200 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 60℃-65℃, and the back temperature of the post-ceramicized heat insulation buffer layer 20 was 55℃-60℃; at 300 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 70℃-75℃, and the back temperature of the post-ceramicized heat insulation buffer layer 20 was 65℃-70℃; at 400 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 80℃-85℃, and the back temperature of the post-ceramicized heat insulation buffer layer 20 was 75℃-80℃; at 500 s... At 600 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 85℃-90℃, and the back temperature of the heat insulation buffer layer 20 after ceramization was 80℃-85℃; at 600 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 90℃-95℃, and the back temperature of the heat insulation buffer layer 20 after ceramization was 85℃-90℃. The above results were obtained from a 200℃ hot bench test on the heat insulation buffer layer 20 before and after ceramization.

[0052] Furthermore, under a 520℃ hot test, at 100 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 90-100℃, and after ceramicization, it was 80℃-90℃; at 200 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 140℃-150℃, and after ceramicization, it was 130℃-140℃; at 300 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 170℃-180℃, and after ceramicization, it was 160℃-170℃; at 400 s, the back temperature of the pre-ceramicized heat insulation buffer layer 20 was 190℃-200℃, and after ceramicization, it was 170℃-180℃; at 5 ... At 600 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 210℃-220℃, and the back temperature of the heat insulation buffer layer 20 after ceramization was 200℃-210℃; at 600 s, the back temperature of the heat insulation buffer layer 20 before ceramization was 230℃-240℃, and the back temperature of the heat insulation buffer layer 20 after ceramization was 210℃-220℃. The above results were obtained from a 520℃ hot bench test on the heat insulation buffer layer 20 before and after ceramization.

[0053] 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.

[0054] 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-ceramic curing, and the hot-stage test diagrams are shown below. Figure 5 and Figure 6 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 5 and Figure 6 It can be seen that in the 200℃ hot test, the cold surface temperature of the pre-ceramicized heat insulation buffer layer 20 after 10 minutes does not exceed 91℃, and the cold surface temperature of the post-ceramicized heat insulation buffer layer 20 after 10 minutes does not exceed 85℃; in the 520℃ hot test, the cold surface temperature of the pre-ceramicized heat insulation buffer layer 20 after 10 minutes does not exceed 232℃, and the cold surface temperature of the post-ceramicized heat insulation buffer layer 20 after 10 minutes does not exceed 219℃.

[0055] In other words, the heat insulation buffer layer 20 exhibits superior heat insulation capabilities both before and after ceramization, with further enhancement after ceramization. Specifically, in this embodiment, the ceramized heat 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 an adjacent cell 100 experiences thermal runaway and high-temperature emissions, this material not only maintains structural integrity through ceramization (as mentioned earlier regarding increased strength), but also actively enhances its heat insulation performance, providing a longer temperature rise buffer for the protected cell 100, thereby effectively extending the trigger time for thermal propagation and improving the overall safety of the battery system.

[0056] 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.

[0057] Further, please refer to Figure 7 In one embodiment, the battery cells adjacent to the battery cell insulation assembly include a first battery cell 41 and a second battery cell 42. The insulation buffer layer 20 includes a first outer surface 21 and a second outer surface 22 disposed opposite to each other; wherein the first outer surface 21 faces the first battery cell 41, and the second outer surface 22 faces the second battery cell 42. The fastener 10 includes a third outer surface 11 and a fourth outer surface 12 disposed opposite to each other; wherein the third outer surface 11 faces the first battery cell 41, and the fourth outer surface 12 faces the second battery cell 42.

[0058] The first outer surface 21 can be the outer surface of the heat insulation buffer layer 20 closest to the first battery cell 41, and the second outer surface 22 can be the outer surface of the heat insulation buffer layer 20 closest to the second battery cell 42. The third outer surface 11 can be the outer surface of the fastener 10 closest to the first battery cell 41, or it can be other than the outer surface of the fastener 10 closest to the first battery cell 41; the fourth outer surface 12 can be the outer surface of the fastener 10 closest to the second battery cell 42, or it can be other than the outer surface of the fastener 10 closest to the second battery cell 42.

[0059] Specifically, the first outer surface 21 is located on the side of the third outer surface 11 away from the first battery cell 41, or the first outer surface 21 is flush with the third outer surface 11; the second outer surface 22 is located on the side of the fourth outer surface 12 away from the second battery cell 42, or the second outer surface 22 is flush with the fourth outer surface 12. That is to say, the outer surface of the heat insulation buffer layer 20 closest to the first battery cell 41 is located on the side of the third outer surface 11 of the fixing member 10 away from the first battery cell 41, or is flush with the third outer surface 11 of the fixing member 10; while the outer surface of the heat insulation buffer layer 20 closest to the second battery cell 42 is located on the side of the fourth outer surface 12 of the fixing member 10 away from the second battery cell 42, or is flush with the fourth outer surface 12 of the fixing member 10.

[0060] Thus, during the charging and discharging process, if the cells 41 and 42 expand, they will preferentially apply pressure to the third outer surface 11 and the fourth outer surface 12 of the fixing member 10, or simultaneously apply pressure to the third outer surface 11 and the fourth outer surface 12 of the fixing member 10 and the first outer surface 11 and the second outer surface 12 of the heat insulation buffer layer 20, so that the fixing member 10 can withstand a certain pressure, thereby reducing the probability that the heat insulation buffer layer 20 will be damaged due to frequent pressure.

[0061] Furthermore, in one embodiment, the ratio of the area of ​​the heat insulation buffer layer 20 to the area of ​​the battery cell 100 is not less than 85%.

[0062] 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 100, and the area of ​​the battery cell 100 can refer to the area of ​​the side of the battery cell 100 facing the heat insulation buffer layer 20. Further, the area of ​​the heat insulation buffer layer 20 facing the side of the battery cell 100 can refer to the area of ​​the heat insulation buffer layer 20 projected (vertically projected) onto the side of the battery cell 100 facing the heat insulation buffer layer 20.

[0063] 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; no limitation is made here. This embodiment, by optimizing the material selection and structural design of the heat insulation buffer layer 20, effectively suppresses thermal runaway propagation while improving battery cycle life and enhancing module mechanical stability, achieving synergistic optimization of battery safety and performance.

[0064] Further, please refer to Figure 8 and Figure 9 In one embodiment, the battery cell 100 in the battery module has an electrode sheet 101 inside, and the battery cell 100 has a main surface 50.

[0065] Specifically, the main surface 50 can refer to the surface with the largest area among all the outer surfaces of the battery cell 100. Specifically, it can be the surface facing other battery cells 100 (such as the surface facing an adjacent battery cell 100) or an adjacent battery cell heat insulation assembly 200, such as the side of the battery cell 100 facing the heat insulation buffer layer 20 in the above embodiment. For example... Figure 7 As shown, the faces of the battery cell 41 facing the first outer surface 21 and the third outer surface 11, and the faces of the battery cell 42 facing the second outer surface 22 and the fourth outer surface 12. Of course, each battery cell 100 may have two opposing main faces 50.

[0066] 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.

[0067] 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 that are interconnected. 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.

[0068] 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 interconnected 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.

[0069] 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 interconnected 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 the cells 100 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 the requirements of cell 100 expansion stress absorption, cycle life improvement, and thermal safety performance of the battery module; no limitations are imposed here.

[0074] In one embodiment, the fastener 10 can be a frame structure, such as a circular frame, a triangular frame, a square frame, a loop frame, or a grid frame formed by structural intersections.

[0075] The fastener 10 can be a closed frame structure or an open frame structure, for example, it can be composed of two or more strip-shaped or rod-shaped structures arranged in parallel, cross, or other similar ways. Specifically, the fastener 10 can be composed of two plastic strip-shaped structures or silicone strip-shaped structures arranged vertically, horizontally, or crosswise. The specific structure and material of the fastener 10 can be selected according to actual needs, and are not specifically limited here.

[0076] When the fixing component 10 is composed of the aforementioned plastic strip structure, silicone strip structure, etc., the width of the plastic strip structure or silicone strip structure can be 1.5 mm to 4 mm, for example, but not limited to 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, and 4 mm. This ensures structural integrity and reliability while reducing the risk of cell malfunction due to pressure damage to the internal winding area of ​​the battery cell.

[0077] Furthermore, the thickness of the fastener 10 is 1.5-3.0 mm, such as, but not limited to, 1.5 mm, 2 mm, 2.5 mm, and 3 mm. The specific thickness can be determined based on the length of the battery module, the thickness of the heat insulation buffer layer 20, and the material of the fastener 10, and is not limited here.

[0078] Furthermore, in one embodiment, the fastener 10 is made of a polymer material. In one embodiment, the fastener 10 is made of PP, PC, etc., which can serve as a skeleton, support, and limiter. Alternatively, it can be made of materials with cushioning properties such as silicone or rubber, so that the fastener 10 can further have a cushioning and shock absorption function.

[0079] Furthermore, in one embodiment, the retaining layer 30 may be made of a high-temperature resistant thin material, with a thickness 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 ensures the necessary structural support strength while minimizing the risk of increased costs or compromised inner layer insulation performance due to excessive thickness.

[0080] 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 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 thermal insulation properties.

[0081] In terms of specific structure, a double-sided attachment method can be adopted to attach the retaining layer 30 to both sides of the heat insulation material, forming a sandwich-like composite structure with the fastener 10 and the heat insulation buffer layer 20; or the heat insulation buffer layer 20 and the fastener 10 can be completely covered by a hot pressing process.

[0082] 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.

[0083] Based on the above structure, the battery cell heat insulation assembly 200 of this application includes the aforementioned fixing member 10, a heat insulation buffer layer 20 located in the accommodating space defined by the fixing member 10, and a retaining layer 30 located outside the fixing member 10 and the heat insulation buffer layer 20 and covering the fixing member 10 and the heat insulation buffer layer 20. The fixing member 10 is made of a polymer material, such as PP or PC, the heat insulation buffer layer 20 is made of a ceramicized heat insulation buffer material, such as ceramicized silicone foam, and the retaining layer 30 is made of a high-temperature resistant material, 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.

[0084] Specifically, before the thermal insulation buffer layer 20 is ceramized, the compression set of the cell thermal insulation component 200 is 2%-4%, such as 2%, 3%, 4%, etc. 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℃ oven for 72 hours, then allowed to recover at room temperature for 30 minutes. The compression set of the sample was then calculated.

[0085] Furthermore, before the thermal insulation buffer layer 20 is ceramized, the cell thermal insulation component 200 undergoes 5000 cycles of cyclic compression, resulting in a compressed thickness of 95-98% of its original thickness, such as 95%, 96%, 97%, or 98%. It should be noted that the original thickness refers to the thickness of the cell thermal insulation component 200 in its natural state before the cyclic compression test, while the compressed thickness refers to the thickness of the 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 cell thermal insulation component 200. The specific operation is as follows: Prepare a 200 sample of a cell thermal insulation component with a thickness of 'a'. Use a cyclic compression test device to 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 is one compression cycle. Perform 5000 compression cycles in this manner. Then measure the thickness of the sample, b, and calculate the thickness retention rate = b / a*100%.

[0086] In other words, the cell insulation component 200 in this embodiment has excellent compressive resilience before ceramicization, which can effectively absorb the mechanical stress generated by the cyclic expansion of the cell 100, thereby providing a long-lasting and stable support for the cell 100.

[0087] In a specific application scenario, the compressive strain cycle curves of the battery cell thermal insulation component 200 before and after the thermal insulation buffer layer 20 is shaped as follows: Figure 10 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 cycle life of the cell 100 in this application.

[0088] Furthermore, under a 30% compression, the compressive stress generated by the pre-ceramicized cell thermal insulation component 200 is 0.20 MPa-0.25 MPa, and the compressive stress generated by the post-ceramicized cell thermal insulation component 200 is 0.30 MPa-0.35 MPa; under a 40% compression, the compressive stress generated by the pre-ceramicized cell thermal insulation component 200 is 0.30 MPa-0.35 MPa, and the compressive stress generated by the post-ceramicized cell thermal insulation component 200 is 0.40 MPa-0.45 MPa; under a 50% compression, the compressive stress generated by the pre-ceramicized cell thermal insulation component 200 is 0.45 MPa-0.50 MPa, and the compressive stress generated by the post-ceramicized cell thermal insulation component 200 is 0.60 MPa-0.65 MPa. The relevant data are based on GB / T18942.1-2003.

[0089] 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.

[0090] Specifically, in one application example, the compressive stress-strain curves of the cell insulation assembly 200 before and after the ceramicization of the insulation buffer layer 20 are as follows: Figure 11 As 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 cell insulation component 200 after the thermal insulation buffer layer 20 is ceramized is significantly higher than before ceramization, indicating that the ceramization of the thermal insulation buffer layer 20 can significantly improve the compressive stress level of the cell insulation component 200.

[0091] Furthermore, under a 520℃ hot-stage test, at 200 s, the back temperature of the cell heat insulation component 200 before the ceramization of the heat insulation buffer layer 20 was 140℃-150℃, and the back temperature of the cell heat insulation component 200 after the ceramization of the heat insulation buffer layer 20 was 135℃-145℃; at 300 s, the back temperature of the cell heat insulation component 200 before ceramization was 170℃-180℃, and the back temperature of the cell heat insulation component 200 after ceramization was 165℃-175℃; at 600 s, the back temperature of the cell heat insulation component 200 before ceramization was 215℃-225℃, and the back temperature of the cell heat insulation component 200 after ceramization was 210℃-220℃. These results were obtained from 520℃ hot-stage tests on the cell heat insulation component 200 before and after the ceramization of the heat insulation buffer layer 20. The specific hot test method is as follows: A stable heat source of 520°C is applied to the lower surface (hot surface) of a sample of a 100*100mm thick battery cell thermal insulation component 200, and then a pressure of 20kPa is applied to the upper surface (back or cold surface) of the sample. At the same time, a temperature sensor is placed to monitor the temperature change of this surface over time.

[0092] 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 12 As shown. The specific hot-table test method is the same as the aforementioned hot-table test method, and will not be repeated here.

[0093] from Figure 12 As can be seen, in the 520℃ hot test, the cold surface temperature of the battery cell insulation component 200 before and after ceramization of the heat insulation buffer layer 20 did not exceed 230℃ 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 has excellent heat insulation performance both before and after ceramization of the heat insulation buffer layer 20, and the heat insulation performance is further improved after ceramization.

[0094] In other words, the cell heat insulation component 200 of this application has excellent compression resilience, mechanical strength and temperature resistance, thereby extending the battery cycle life and ensuring the integrity of the module structure by blocking heat diffusion and absorbing expansion force.

[0095] In the cell heat insulation assembly 200 of the battery module of this application, the fixing member 10 can limit the heat insulation buffer layer 20 and control the spacing between the cells 100, ensuring the cells 100 are grouped together. The heat insulation buffer layer 20 has both heat insulation protection 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. The retaining layer 30 covers the fixing member 10 and the heat insulation buffer layer 20, which can provide fixed support for the entire cell heat insulation assembly 200 and improve 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.

[0096] 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: Fasteners are defined to have accommodating space; A heat-insulating buffer layer is disposed within the accommodating space; and At least one retaining layer is disposed on one side of the fastener and the heat insulation buffer layer, and covers the fastener and the heat insulation buffer layer.

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

3. The battery module according to claim 2, characterized in that, The adjacent battery cells include a first battery cell and a second battery cell. The heat insulation buffer layer includes a first outer surface and a second outer surface disposed opposite to each other, with the first outer surface facing the first battery cell and the second outer surface facing the second battery cell. The fixing member includes a third outer surface and a fourth outer surface disposed opposite to each other, with the third outer surface facing the first battery cell and the fourth outer surface facing the second battery cell. The first outer surface is located on the side of the third outer surface away from the first battery cell, or the first outer surface is flush with the third outer surface. The second outer surface is located on the side of the fourth outer surface away from the second battery cell, or the second outer surface is flush with the fourth outer surface.

4. 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%.

5. 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 component on the main surface, and the area of ​​the second projection is smaller than the area of ​​the first projection.

6. The battery module according to claim 5, characterized in that, The main surface includes a first cell edge, a second cell edge, a third cell edge, and a fourth cell edge that are connected to each other, wherein the first cell edge and the third cell edge are arranged opposite to each other in the length direction of the cell, and the second cell edge and the fourth cell edge are arranged 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.

7. The battery module according to claim 6, 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.

8. The battery module according to claim 1, characterized in that, The thickness of the heat insulation buffer layer is 1.5 mm-3 mm.

9. 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 <5%; and after 5000 cycles of compression, the thickness retention rate of the heat insulation buffer layer is more than 95%. Before ceramization, the hardness of the heat insulation buffer layer is 15 Shore A-20 Shore A; after ceramization, the hardness of the heat insulation buffer layer is 30 Shore A-40 Shore A. 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.

10. 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. Under a 200℃ hot plate test, the back temperature of the heat insulation buffer layer before ceramization was 60℃-65℃ after 200 s, and the back temperature of the heat insulation buffer layer after ceramization was 55℃-60℃; after 300 s, the back temperature of the heat insulation buffer layer before ceramization was 70℃-75℃, and the back temperature of the heat insulation buffer layer after ceramization was 65℃-70℃; after 600 s, the back temperature of the heat insulation buffer layer before ceramization was 90℃-95℃, and the back temperature of the heat insulation buffer layer after ceramization was 85℃-90℃. Under a 520℃ hot test, the back temperature of the heat insulation buffer layer before ceramization was 140℃-150℃ after 200 s, and the back temperature of the heat insulation buffer layer after ceramization was 130℃-140℃; after 300 s, the back temperature of the heat insulation buffer layer before ceramization was 170℃-180℃, and the back temperature of the heat insulation buffer layer after ceramization was 160℃-170℃; after 600 s, the back temperature of the heat insulation buffer layer before ceramization was 230℃-240℃, and the back temperature of the heat insulation buffer layer after ceramization was 210℃-220℃.

11. The battery module according to claim 1, characterized in that, The thickness of the fastener is 1.5 mm to 3 mm.

12. The battery module according to claim 1, characterized in that, The fastener has a frame structure, and the accommodating space extends through the frame structure along the arrangement direction of the plurality of battery cells.

13. The battery module according to claim 1, characterized in that, The thickness of the retaining layer is 0.05 mm to 0.1 mm.

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 set of the battery cell heat insulation component is 2%-4%; and after 5000 cycles of compression, the thickness retention rate of the battery cell heat insulation component is 95%-98%. Under 30% compression, the compressive stress of the battery cell heat insulation component before the heat insulation buffer layer is ceramicized is 0.20 MPa-0.25 MPa, and the compressive stress of the battery cell heat insulation component after the heat insulation buffer layer is ceramicized is 0.30 MPa-0.35 MPa; under 40% compression, the compressive stress of the battery cell heat insulation component before the heat insulation buffer layer is ceramicized is 0.30 MPa-0.35 MPa, and the compressive stress of the battery cell heat insulation component after the heat insulation buffer layer is ceramicized is 0.40 MPa-0.45 MPa; under 50% compression, the compressive stress of the battery cell heat insulation component before the heat insulation buffer layer is ceramicized is 0.45 MPa-0.50 MPa, and the compressive stress of the battery cell heat insulation component after the heat insulation buffer layer is ceramicized is 0.60 MPa-0.65 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 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℃ hot test, at 200 s, the back temperature of the battery cell heat insulation component before the heat insulation buffer layer was 140℃-150℃, and after the heat insulation buffer layer was ceramicized, the back temperature of the battery cell heat insulation component was 135℃-145℃; at 300 s, the back temperature of the battery cell heat insulation component before the heat insulation buffer layer was ceramicized was 170℃-180℃, and after the heat insulation buffer layer was ceramicized, the back temperature of the battery cell heat insulation component was 165℃-175℃; at 600 s, the back temperature of the battery cell heat insulation component before the heat insulation buffer layer was ceramicized was 215℃-225℃, and after the heat insulation buffer layer was ceramicized, the back temperature of the battery cell heat insulation component was 210℃-220℃.

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