Cover plate structure and battery cell

Abstract

The application relates to the technical field of batteries, in particular to a cover plate structure and a battery cell. The cover plate structure comprises a cover plate body, an explosion-proof valve and a supporting assembly. The supporting assembly comprises a supporting plate part and a plurality of supporting protrusions. The cover plate body is provided with an explosion-proof hole penetrating through the cover plate body along a first direction, and the explosion-proof valve is arranged in the explosion-proof hole. The supporting protrusions are integrally connected to the side of the cover plate body facing the pole group in the first direction. The plurality of supporting protrusions are arranged at intervals along the edge of the explosion-proof hole, and the supporting plate part is lapped on the supporting protrusions, so that the supporting plate part and the cover plate body are arranged at intervals along the first direction. According to the cover plate structure and the battery cell, when a thermal runaway accident occurs in the battery cell, the supporting assembly can effectively support the pole group, and the pole group is prevented from blocking the explosion-proof hole. The plurality of supporting protrusions are arranged at intervals along the edge of the explosion-proof hole, the interval between the adjacent supporting protrusions is utilized to realize the communication between the inside and the outside of the supporting space, and the smoothness of the exhaust of the battery cell is ensured.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate structure and a battery cell. Background Technology

[0002] The demand for large capacity and high safety performance in the energy storage cell field is increasing. In existing technologies, blade-type energy storage cells typically adopt a structure in which the terminals are led out on the same side and the explosion-proof valve is set on the opposite side cover plate to achieve thermal and electrical separation and improve the intrinsic safety performance of the cell.

[0003] However, when a thermal runaway accident occurs in a battery cell, the explosion-proof valve opens to release pressure and vent air, creating a rapid, high-temperature, and high-pressure airflow inside the cell. This airflow strongly impacts the internal electrode assembly, driving it towards the side where the explosion-proof valve is located. Once the electrode assembly moves, its front end can easily block the exhaust channel of the explosion-proof valve, obstructing airflow and significantly reducing the valve's pressure release and venting efficiency. Consequently, it cannot effectively curb the development of thermal runaway, severely weakening the overall safety assurance capability of the battery cell and hindering the application and promotion of blade energy storage cells in scenarios with high reliability requirements. Summary of the Invention

[0004] The purpose of this application is to provide a cover structure and a battery cell to address, to some extent, the technical problem in the prior art where, during a thermal runaway accident in the battery cell, the explosion-proof valve opens to release pressure and vent air, creating a rapid, high-temperature, and high-pressure airflow inside the cell. This airflow strongly impacts the internal electrode assembly, driving it towards the side where the explosion-proof valve is located. Once the electrode assembly moves, its front end can easily block the exhaust channel of the explosion-proof valve, obstructing airflow and significantly reducing the pressure relief and exhaust efficiency of the explosion-proof valve. Consequently, it cannot effectively curb the development of thermal runaway and severely weakens the overall safety assurance capability of the battery cell.

[0005] According to a first aspect of this application, a cover plate structure is provided for a battery cell. The battery cell includes an electrode group and the cover plate structure arranged sequentially along a first direction. The cover plate structure includes a cover plate body, an explosion-proof valve, and a support assembly. The support assembly includes a support plate portion and a plurality of support protrusions. The cover plate body is provided with an explosion-proof hole penetrating itself along the first direction. The explosion-proof valve is disposed in the explosion-proof hole. The support protrusion is integrally connected to the side of the cover plate body facing the pole group in the first direction. A plurality of the support protrusions are spaced apart along the edge of the explosion-proof hole. The support plate portion overlaps the support protrusion, such that the support plate portion and the cover plate body are spaced apart along the first direction.

[0006] Preferably, the cover plate body and the supporting protrusion are integrally stamped parts; The support protrusion includes a first protrusion and a second protrusion connected sequentially along the first direction. The first protrusion is connected to the cover plate body, and the second protrusion is connected to the support plate portion. In this process, the supporting protrusion is projected along the first direction onto a plane perpendicular to the first direction, the projected area of ​​the second protrusion is smaller than the projected area of ​​the first protrusion, and the first protrusion completely covers the second protrusion.

[0007] Preferably, the dimension of the cover plate body in the first direction is T1, wherein 2.0mm≤T1≤2.5mm; The wall thickness of the first boss is T2, where 1.5mm ≤ T2 ≤ 2.0mm; The dimension of the first boss in the first direction is H1, where 0.7 ≤ ≤0.8; The second boss has a dimension H2 in the first direction, where 0.55 ≤ ≤0.75, 2.0mm≤H1+H2≤4.0mm.

[0008] Preferably, the support plate includes a plurality of integrally connected support components, each support component having an extending direction, and support protrusions are provided at both ends of each support component in the extending direction. The support component includes a first support bar extending along a second direction and a second support bar extending along a third direction, the second direction and the third direction intersecting each other, and the plane defined by the second direction and the third direction intersecting the first direction.

[0009] Preferably, the support plate further includes reinforcing ribs, and each support member is provided with a plurality of reinforcing ribs. The plurality of reinforcing ribs are spaced apart along the extension direction of the corresponding support member, and the reinforcing ribs protrude from the support member along the first direction toward the side opposite to the cover plate body at a predetermined height.

[0010] Preferably, the dimension of the support member in the direction perpendicular to the extension direction is A3, wherein 8mm≤A3≤13.5mm; And / or, the dimension of the support member in the first direction is t1, wherein 0.8mm≤t1≤1.2mm; And / or, the dimension of the reinforcing rib in the first direction is t2, wherein 0.2mm≤t2≤0.5mm.

[0011] Preferably, the dimension of the cover plate body in the second direction is A1, wherein 155mm≤A1≤180mm; The dimension of the pole group in the second direction is L1, the dimension of the support assembly in the second direction is A2, and the sum of the dimensions of the support plate in the first direction and the dimensions of the support protrusion in the first direction is H3, wherein 0.35 ≤ ≤0.45; And / or, the dimension of the cover plate body in the third direction is B1, wherein 40mm ≤ B1 ≤ 58mm, and the dimension of the support assembly in the third direction is B2, wherein 5mm ≤ ≤8mm.

[0012] Preferably, the effective opening area S0 of the explosion-proof valve and the end area S1 of the side of the support plate facing the electrode assembly are both S1, wherein 1.85 ≤ ≤2.2.

[0013] Preferably, the support assembly further includes an adhesive portion that bonds the support protrusion to the support plate portion.

[0014] According to a second aspect of this application, a battery cell is provided, including the cover plate structure described in any of the above technical solutions, and thus possesses all the beneficial technical effects of the cover plate structure, which will not be repeated here.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: The cover structure provided in this application, on the one hand, utilizes a support assembly consisting of a support protrusion integrally connected to the cover body and a support plate portion overlapping the support protrusion to enclose a support space on the side of the explosion-proof hole facing the electrode group. In the event of a thermal runaway accident in the battery cell, this support assembly can effectively support the electrode group and prevent the electrode group from blocking the explosion-proof hole. On the other hand, by having multiple support protrusions spaced apart along the edge of the explosion-proof hole, the spacing between adjacent support protrusions enables communication between the inside and outside of the support space, thereby ensuring the smooth venting of the battery cell.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is an isometric structural diagram of the cover plate structure provided in the embodiments of this application; Figure 2 for Figure 1 An enlarged structural diagram of the provided cover plate structure at point D; Figure 3 This is an exploded structural diagram of the cover plate structure provided in the embodiments of this application; Figure 4 This is a front view of the cover plate structure provided in the embodiments of this application; Figure 5 This is a side view of the cover plate structure provided in an embodiment of this application; Figure 6 This is an isometric structural diagram of the support plate portion provided in an embodiment of this application; Figure 7 This is a side view of the support plate portion provided in an embodiment of this application; Figure 8 A side view of the cover plate body provided in an embodiment of this application; Figure 9 This is an exploded structural diagram of a portion of the battery cell provided in an embodiment of this application; Figure 10 This is an isometric structural diagram of the shell body provided in an embodiment of this application; Figure 11 This is an isometric structural schematic diagram of the insulating tray provided in the embodiments of this application; Figure 12 This is a side view of the insulating tray provided in an embodiment of this application.

[0019] Figure label: 11-Cover plate body; 110-Explosion-proof hole; 12-Explosion-proof valve; 13-Support plate part; 131-Support component; 1311-First support bar; 1312-Second support bar; 132-Reinforcing rib; 14-Support protrusion; 141-First boss; 142-Second boss; 15-Adhesive part; 2-Insulating support plate; 21-Blocking part; 22-Limiting part; 23-Adhesive backing part; 24-Ventilation hole; 3-Electrode group; 31-Layered part; 32-Insulating film part; 4-Electrode post cover plate; 5-Shell body; F1-First direction; F2-Second direction; F3-Third direction. Detailed Implementation

[0020] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0021] The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application.

[0022] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] The following reference Figures 1 to 12 This application describes a cover plate structure and a battery cell according to some embodiments.

[0026] See Figures 1 to 12 As shown, an embodiment of the first aspect of this application provides a cover plate structure for a battery cell. The battery cell includes an electrode group 3 and a cover plate structure arranged sequentially along a first direction F1. The cover plate structure includes a cover plate body 11, an explosion-proof valve 12, and a support assembly. The support assembly includes a support plate portion 13 and a plurality of support protrusions 14. The cover plate body 11 is provided with an explosion-proof hole 110 penetrating itself along the first direction F1, and the explosion-proof valve 12 is disposed in the explosion-proof hole 110. The support protrusions 14 are integrally connected to one side of the cover plate body 11 in the first direction F1. The plurality of support protrusions 14 are spaced apart along the edge of the explosion-proof hole 110. The support plate portion 13 overlaps the support protrusions 14, so that the support plate portion 13 and the cover plate body 11 are spaced apart along the first direction F1.

[0027] According to the cover structure provided by the above technical features, on the one hand, a support assembly consisting of a support protrusion 14 integrally connected to the cover body 11 and a support plate portion 13 overlapping the support protrusion 14 is formed to enclose a support space on the side of the explosion-proof hole 110 facing the electrode group 3. When a thermal runaway accident occurs in the battery cell, the support assembly can effectively support the electrode group 3 and prevent the electrode group 3 from blocking the explosion-proof hole 110. On the other hand, by having multiple support protrusions 14 spaced along the edge of the explosion-proof hole 110, the spacing between adjacent support protrusions 14 is used to achieve communication between the inside and outside of the support space, thereby ensuring the smoothness of battery cell venting.

[0028] like Figure 1 , Figures 3 to 11 As shown in the figure, F1 can be an example of the first direction F1 mentioned above. For ease of description, the two intersecting directions on the plane that intersect with the first direction F1 are defined as the second direction F2 and the third direction F3, respectively. Figure 1 , Figures 3 to 11 As shown in the figure, F2 is an example of the second direction F2 described above, and F3 is an example of the third direction F3 described above. Preferably, the second direction F2 and the third direction F3 are perpendicular to each other, and the plane containing both the second direction F2 and the third direction F3 is perpendicular to the first direction F1, so as to accommodate most cylindrical or square battery cells. Figure 9 and Figure 10 Taking a square battery cell as an example, the first direction F1 can be the length direction of the battery cell. The second direction F2 can be the width direction of the battery cell. The third direction F3 can be the thickness direction of the battery cell. The dimension of the battery cell in the thickness direction is smaller than or equal to the dimension of the battery cell in the width direction.

[0029] Preferably, such as Figure 2 As shown, the cover plate body 11 and the support protrusion 14 can be a single stamped part, which not only facilitates the processing of the support protrusion 14, but also effectively improves the processing accuracy of the support protrusion 14.

[0030] Preferably, such as Figure 2 As shown, the support protrusion 14 includes a first protrusion 141 and a second protrusion 142 connected sequentially along the first direction F1. The first protrusion 141 is connected to the cover plate body 11, and the second protrusion 142 is connected to the support plate portion 13. In this way, the processing difficulty of the support protrusion 14 in the stamping process is reduced, and the processing yield of the support protrusion 14 is improved.

[0031] Furthermore, the support protrusion 14 is projected along the first direction F1 onto a plane perpendicular to the first direction F1. The projected area of ​​the second protrusion 142 is smaller than the projected area of ​​the first protrusion 141, and the first protrusion 141 completely covers the second protrusion 142. In other words, the second protrusion 142 is uniformly reduced in size relative to the first protrusion 141 towards the center of the first protrusion 141. This ensures the uniformity of deformation of the second protrusion 142 in all directions, guarantees the finished product yield of the support protrusion 14, and effectively evens out the stress distribution of the support protrusion 14, thereby reducing the risk of deformation and breakage of the support protrusion 14.

[0032] like Figure 2 As shown in the figure, the first protrusion and the second protrusion are both rectangular bosses. However, they are not limited to this. As long as the stable support for the support plate portion 13 can be guaranteed, the first protrusion and the second protrusion can also be circular bosses, elliptical bosses, conical bosses or other irregular bosses.

[0033] Preferably, such as Figure 8 As shown, the dimension of the cover plate body 11 in the first direction F1 can be expressed as T1, where 2.0mm≤T1≤2.5mm, T1≥2.0mm can ensure the support strength of the cover plate body 11 and the stamping allowance of the support protrusion 14; T1≤2.5mm can effectively balance the mass energy density of the battery cell and the manufacturing cost of the cover plate body 11.

[0034] Preferably, 0.7≤ ≤0.8, where H1 is the dimension of the first boss 141 in the first direction F1, so as to balance the stamping yield of the first boss 141 and the support effectiveness of the support protrusion 14.

[0035] It should be noted that the first and second protrusions mentioned above are formed by stamping the cover plate body 11. That is to say, the side of the first and second protrusions opposite to the pole group 3 is a hollow structure. Preferably, the wall thickness of the first protrusion 141 can be expressed as T2, where 1.5mm≤T2≤2.0mm, so as to take into account both the supporting strength of the first protrusion 141 and the stamping allowance of the second protrusion.

[0036] Preferably, 0.55≤ ≤0.75, wherein the dimension of the second boss 142 in the first direction F1 is H2, so as to balance the stamping yield of the second boss 142 and the support effectiveness of the support protrusion 14.

[0037] Preferably, 2.0mm≤H1+H2≤4.0mm, so as to balance the support effectiveness of the support protrusion 14 and the stamping difficulty of the support protrusion 14.

[0038] Preferably, such as Figure 5As shown, the dimension of the above-mentioned support component in the first direction F1 is H3, wherein 3.5mm≤H3≤5.5mm, so as to ensure the effectiveness of the support component in supporting the pole group 3.

[0039] Taking the above-mentioned support component as an example of a structure in which the support protrusion 14 and the support plate portion 13 are matched, the size of the above-mentioned support component in the first direction F1 can be understood as the sum of the sizes of the support protrusion 14, the support plate portion 13, and the structure connecting the support protrusion 14 and the support plate portion 13 (such as the adhesive portion 15 described below) in the first direction F1.

[0040] In an embodiment, such as Figure 1 , Figure 3 , Figure 4 and Figure 6 As shown, the support plate portion 13 includes a plurality of integrally connected support components 131. The support components 131 have an extending direction, and support protrusions 14 are provided at both ends of the extending direction of each support component 131 to ensure the support stability of the support plate portion 13.

[0041] Preferably, such as Figure 1 , Figure 3 , Figure 4 and Figure 6 As shown, the support component 131 includes a first support bar 1311 extending along the second direction F2 and a second support bar 1312 extending along the third direction F3. Thus, on the one hand, the vertically interlaced layout of the first support bar 1311 and the second support bar 1312 ensures effective support for the electrode group 3 and maintains the structural rigidity of the support plate 13, without completely blocking the airflow channel between the inside of the cell and the explosion-proof hole 110. This further ensures that the explosion-proof valve 12 can efficiently complete the pressure relief operation, quickly reduce the internal pressure of the cell, and prevent safety accidents such as thermal runaway propagation and shell rupture. On the other hand, the first support bar 1311 and the second support bar 1312 extend along the second direction F2 and the third direction F3, respectively. The structure is simple and regular, and the assembly fit with the cover plate body 11 and the support legs is high. This ensures both the ease of processing the support body and the precise docking of the bracket assembly with the explosion-proof hole 110 and the cover plate body 11. It is compatible with the cover plate structure size requirements of most large-capacity blade energy storage cells and does not increase the assembly difficulty of the overall cell structure.

[0042] like Figure 6 As shown in the figure, an example of the above-mentioned support part including a first support bar 1311 and two second support bars 1312 is shown, wherein the first support bar 1311 is located in the middle of the second support bars 1312. However, it is not limited to this. The number of the first support bar 1311 and the second support bar 1312 can be adaptively adjusted according to the size of the explosion-proof hole 110 and the size of the support part.

[0043] Preferably, such as Figure 1 , Figure 3 , Figure 4 and Figure 6 As shown, the support plate portion 13 also includes reinforcing ribs 132. Each support component 131 is provided with multiple reinforcing ribs 132. The multiple reinforcing ribs 132 are spaced apart along the extension direction of the corresponding support component 131. The reinforcing ribs 132 protrude from the support component 131 along the first direction F1 toward the side opposite to the cover plate body 11 by a predetermined height. In this way, by providing multiple reinforcing ribs 132 spaced apart along the extension direction on each support portion, the structural rigidity and impact resistance of the first support bar 1311 and the second support bar 1312 can be effectively increased, the stress generated by the impact of the electrode group 3 can be dispersed, the support portion can be prevented from deforming or breaking under stress, and the support plate portion 13 can be guaranteed to play a long-term and stable limiting and blocking role, thus avoiding the problem of shielding the explosion-proof valve 12 due to the failure of the support structure.

[0044] like Figure 6 As shown, taking the first support bar 1311 as an example, the corresponding extension direction is the second direction F2. That is, on the first support bar 1311, multiple reinforcing ribs 132 are spaced apart along the second direction F2, wherein each reinforcing rib 132 extends along a direction perpendicular to the extension direction (i.e., the third direction F3).

[0045] Optionally, such as Figure 6 As shown, the reinforcing rib 132 can be integrally stamped with the support portion.

[0046] Preferably, such as Figure 4 As shown, 8mm ≤ A3 ≤ 13.5mm, where A3 is the dimension of the support member 131 in the direction perpendicular to the extension direction. In other words, the A3 value represents the width of the support member 131. For example, the A3 value of the first support bar 1311 is the dimension of the first support bar 1311 in the third direction F3, and the A3 value of the second support bar 1312 is the dimension of the second support bar 1312 in the second direction F2. In this way, the support strength of the support plate 13 and the exhaust efficiency of the explosion-proof valve 12 are effectively balanced.

[0047] Preferably, such as Figure 7 As shown, 0.8mm≤t1≤1.2mm, where t1 is the dimension of the support member 131 in the first direction F1, so as to balance the support strength of the support member 131 and the space occupancy rate of the support member 131 in the first direction F1.

[0048] Preferably, such as Figure 7As shown, 0.2mm≤t2≤0.5mm, where t2 is the dimension of the reinforcing rib 132 in the first direction F1, so as to balance the support strength of the support plate part 13 and the space occupancy rate of the support plate part 13 in the first direction F1.

[0049] Preferably, such as Figure 8 As shown, 155mm≤A1≤180mm, where A1 is the dimension of the cover plate body 11 in the second direction F2 to accommodate the size of most square cells.

[0050] Similarly, such as Figure 8 As shown, 40mm≤B1≤58mm, where B1 is the dimension of the cover plate body 11 in the third direction F3.

[0051] Preferably, such as Figure 4 As shown in Table 1, 0.35≤ ≤0.45, where L1 is the dimension of pole group 3 in the second direction F2, A2 is the dimension of support assembly in the second direction F2, and H3 is the sum of the dimensions of support plate portion 13 in the first direction F1 and support protrusion 14 in the first direction F1. This ensures that the dimensions of pole group 3 match the dimensions of support assembly, guaranteeing the effectiveness of support assembly in supporting pole group 3. If the height of the support component is ≤0.35, the support assembly height is insufficient, resulting in poor support for electrode group 3 and failure of the cell safety test. Disassembly of the cell revealed slight signs of movement in electrode group 3. If the height is ≥0.45, the support components are too high, occupying too much internal space of the cell and having too much impact on the volumetric energy density of the cell.

[0052] Preferably, 5mm≤ ≤8mm, where B2 is the dimension of the support component in the third direction F3. Thus, considering the support effectiveness of the support component and the stamping yield of the support protrusion 14, in other words, The feedback value is the distance from the support protrusion 14 on the third direction F3 to one edge of the cover body 11 on the third direction F3. If the distance is too large, the pole assembly 3 is prone to drooping and blocking the exhaust channel on one side of the support component on the third direction F3. If the distance is too small, it may cause the edge of the cover body 11 to bend and deform or the stamping shape of the support protrusion 14 to be unsatisfactory during the stamping process of the support protrusion 14.

[0053] In the embodiments, as shown in Table 1, 1.85 ≤ ≤2.2, where S0 is the effective opening area of ​​the explosion-proof valve 12, and S1 is the end area of ​​the support plate 13 on the side facing the electrode group 3. That is, S1 can be understood as the effective support area of ​​the support plate 13, which is the sum of the end area of ​​the first support bar 1311, the second support bar 1312, and the reinforcing rib 132 on the side facing the electrode group 3. In this way, the explosion-proof valve 12 is associated with the effective support area of ​​the support plate, so that the support plate can match the exhaust efficiency of the explosion-proof valve 12. If the value is ≤1.85, the stability of the support component is poor, and pole group 3 will still experience cross-flow, affecting the opening of explosion-proof valve 12; if If the value is ≥2.2, the supporting components will block the exhaust channel too much, affecting the exhaust efficiency.

[0054] Select rated discharge energy for Rated charging power for Rated voltage for Ten groups of battery cells were subjected to thermal runaway performance tests. The parameters of the ten cells in each group were the same. The values ​​of A1, A2, H3, L1, S0 and S1 of the cells in different groups are shown in the table below.

[0055] Test environment: The battery cell under test is placed in the thermal runaway test apparatus. A sheet-like heating element is arranged on the largest surface area of ​​the battery cell. The size of the sheet-like heating element is no larger than the area of ​​the largest surface area of ​​the battery cell, and the power of the heating element needs to be greater than [missing information]. (For example, the power of the heating element can be) ); Test equipment: A temperature sensor with a diameter of less than 1 mm is placed at the center of the other surface with the largest area in the battery cell. The temperature sampling period is set to 1 second, and the test is set to continuously detect three temperature rise rate values ​​that are all greater than or equal to... Alternatively, fire or explosion can be used as the criteria for determining thermal runaway. The test cell is then connected to the charging and discharging device and its voltage data sampling line. Experimental method: Perform constant current charging, start heating, and record time, voltage, current, temperature, and temperature rise rate. Record experimental phenomena, including expansion, leakage, smoke, fire, explosion, shell rupture, and rupture location; trigger the judgment condition for thermal runaway or when the temperature reaches... Or the test time reaches When the time is up, stop the power supply and heating, observe for 1 hour, and record the time, voltage, current, temperature, temperature rise rate, and test phenomena, including expansion, leakage, smoke, fire, explosion, shell cracking, crack location, and electrode group movement.

[0056] The test results of 10 groups of battery cells are as follows: Table 1:

[0057] In an embodiment, such as Figure 2 and Figure 3 As shown, the support assembly also includes an adhesive portion 15, which bonds the support protrusion 14 to the support plate portion 13. In this way, on the one hand, the support plate portion 13 and the support protrusion 14 are fixed together; on the other hand, the adhesive portion 15 effectively solves the connection compatibility problem between support plate portions 13 and support protrusions 14 made of different materials (for example, the support protrusion 14 can be made of the same metal material as the cover plate body 11, such as aluminum or stainless steel, to facilitate fixing the support protrusion 14 by stamping, welding, etc.; the support plate portion 13 can be made of insulating materials such as plastic or rubber to improve the insulation between the electrode assembly 3 and the cover plate structure).

[0058] Optionally, the aforementioned adhesive portion 15 can be an insulating adhesive, which can be a temperature- and electrolyte-resistant colloid with good stability. The temperature resistance range of the insulating adhesive can be -40℃ to 85℃, and the insulating adhesive can meet the following requirements: peel force N > 28.8N at 180°, and its holding force can meet the following requirements: no peeling for > 60 hours, and initial tack force > 25N, to ensure the bonding effect.

[0059] The second aspect of this application also provides a battery cell, including the above-described electrode group 3 and the cover plate structure described in any of the above embodiments, thus possessing all the beneficial technical effects of the cover plate structure, which will not be repeated here.

[0060] Preferably, such as Figures 9 to 12 As shown, the battery cell also includes an insulating support plate 2, which is disposed on the side of the electrode group 3 facing the cover structure to achieve insulation between the electrode group 3 and the cover structure. In this way, the traditional plastic structure of the cover plate is eliminated, which not only better adapts to the structure of the support assembly, but also effectively saves the space occupied by the insulating parts between the cover structure and the battery cell, further reducing the impact of the support assembly on the volumetric energy density of the battery cell.

[0061] Preferably, the insulating tray 2 can be made of an insulating material (e.g., PP, etc.), such as Figures 9 to 12 As shown, the insulating plate 2 can be sheet-like, and the insulating plate 2 can cover the end of the pole group 3 facing the cover structure.

[0062] Optionally, the material of the insulating tray 2 can meet the following requirements: tensile strength ≥ 50 MPa, elastic modulus E ≥ 1100 MPa, and elongation A ≥ 85%, so as to ensure the durability of the insulating tray 2 and the limiting energy for the following electrode group 3.

[0063] Preferably, such as Figure 12 As shown, the wall thickness of the above-mentioned insulating tray 2 can be expressed as t, where 0.5mm≤t≤1mm, in order to balance the insulation and economy of the insulating tray 2.

[0064] Preferably, such as Figure 11 As shown, the insulating tray 2 may include a partition body and an adhesive backing 23. The adhesive backing 23 is disposed on the side of the partition body facing the electrode group 3 and is used to bond the electrode group 3 to the partition body to achieve the fixation between the insulating tray 2 and the electrode group 3.

[0065] Optionally, the adhesive backing 23 can be an insulating adhesive, which on the one hand ensures the durability and high-temperature resistance of the adhesive backing 23 in the electrolyte environment; on the other hand, it further improves the insulation between the electrode assembly 3 and the aforementioned cover plate structure. Optionally, the temperature resistance range of the adhesive backing 23 is between -40℃ and 85℃, and the adhesive backing 23 also needs to meet the following requirements: peel force N at 180° > 35N, and remain intact for more than 60 hours without falling off; initial tack > 25N, thus ensuring the adhesion effect of the aforementioned insulating tray 2.

[0066] Preferably, such as Figure 10 and Figure 12 As shown, the partition body may include a partition part 21 and a limiting part 22 connected to each other. The limiting part 22 is connected to both sides of the partition part 21 in the second direction F2. The limiting part 22 is provided on the side of the pole group 3 in the second direction F2, thus ensuring the complete coverage of the pole group 3 by the insulating support plate 2.

[0067] Preferably, the total area of ​​the mounting surfaces of the insulating tray 2 and the electrode assembly 3 is S2, and the area of ​​the adhesive backing 23 is S3, wherein 0.1 ≤ ≤0.15, thus, ≥0.1 can effectively ensure the bonding stability of the insulating tray 2 and prevent the insulating tray 2 from falling off and moving relative to the pole group 3; With a thickness of ≤0.15, the usable area of ​​the adhesive backing 23 can be effectively saved, reducing the space occupied by the adhesive backing 23 and the cost of adhesive application. It should be noted that the total area of ​​the assembly surfaces of the insulating tray 2 and the electrode group 3 can be understood as the total contact area of ​​the insulating tray 2 and the electrode group 3.

[0068] Preferably, such as Figure 11 As shown, the partition body is also provided with a vent 24 that penetrates itself along the first direction F1, so as to guide the gas inside the electrode group 3 to the cover plate structure.

[0069] Preferably, the aperture of the above-mentioned vent 24 can be expressed as φ, where 4mm≤φ≤6mm. In this way, particulate impurities in the electrode group 3 can be effectively prevented from falling into the shell and the insulation of the shell can be guaranteed.

[0070] Preferably, the insulating tray 2 is projected along the first direction F1 onto a plane perpendicular to the first direction F1, so that the total projected area of ​​all the vent holes 24 can account for 3% to 6% of the projected area of ​​the insulating tray 2, so as to take into account the supporting strength, insulation and exhaust efficiency of the insulating tray 2.

[0071] Preferably, such as Figure 9 As shown, the end of the electrode group 3 facing the cover plate structure is provided with a clearance groove, which is provided in correspondence with the support component. In this way, the impact of the support component on the volumetric energy density of the cell is further reduced.

[0072] Optionally, not shown in the figure, the electrode assembly 3 may include a stacked portion 31 and an insulating film portion 32. The stacked portion 31 is formed by alternating stacking of positive and negative electrode sheets. The insulating film portion 32 covers the outside of the stacked portion 31 to achieve insulation of the electrode assembly 3. It should be noted that the structure of the electrode assembly 3 is a conventional structure in the art and will not be described in detail here. Optionally, the insulating tray 2 can be attached to the outside of the insulating film portion 32 by means of an adhesive backing portion 23.

[0073] Correspondingly, such as Figure 9 As shown, the partition 21 is also provided with a relief groove at the position corresponding to the relief groove. In other words, the insulating support plate 2 is provided in the same shape as the end of the pole group 3 near the cover plate structure.

[0074] Optionally, such as Figure 10 As shown, the aforementioned battery cell may further include a housing, which may include a housing body 5, the aforementioned cover plate structure, and a terminal cover plate 4. The aforementioned cover plate structure and the terminal cover plate 4 may be respectively disposed opposite to each other on both sides of the housing in the first direction F1 to form a closed space for accommodating the aforementioned electrode group 3. It should be noted that the aforementioned terminal cover plate 4 can be understood as a cover plate on the terminal setting side of the battery cell. The terminal cover plate 4 is a prior art structure and will not be described in detail here.

[0075] Preferably, such as Figure 9 As shown, in the second direction F2, the size of the pole group 3 can be represented as L1, and the size of the insulating support plate 2 can be represented as L2, where 1mm≤L1-L2≤1.5mm. That is to say, the insulating support plate 2 and the pole group 3 are interference fit. In this way, the insulating support plate 2 can constrain the end of the pole group 3 near the cover plate structure, thereby facilitating the smooth installation of the pole group 3 into the shell body 5.

[0076] Preferably, not shown in the figure, on the third direction F3, the size of the electrode group 3 can be represented as W1, and the size of the insulating tray 2 can be represented as W2, wherein 1mm≤W1-W2≤2mm, so as to avoid interference between the insulating tray 2 and the shell body 5 during the process of inserting the electrode group 3 into the shell.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A cover plate structure, characterized in that, For use in battery cells, the battery cells include electrode groups and the cover plate structure arranged sequentially along a first direction, the cover plate structure includes a cover plate body, an explosion-proof valve and a support assembly, the support assembly includes a support plate portion and a plurality of support protrusions, the cover plate body is provided with an explosion-proof hole penetrating itself along the first direction, and the explosion-proof valve is disposed in the explosion-proof hole; The support protrusion is integrally connected to the side of the cover plate body facing the pole group in the first direction. A plurality of the support protrusions are spaced apart along the edge of the explosion-proof hole. The support plate portion overlaps the support protrusion, such that the support plate portion and the cover plate body are spaced apart along the first direction.

2. The cover plate structure according to claim 1, characterized in that, The cover plate body and the support protrusion are both integral stamped parts; The support protrusion includes a first protrusion and a second protrusion connected sequentially along the first direction. The first protrusion is connected to the cover plate body, and the second protrusion is connected to the support plate portion. In this process, the supporting protrusion is projected along the first direction onto a plane perpendicular to the first direction, the projected area of ​​the second protrusion is smaller than the projected area of ​​the first protrusion, and the first protrusion completely covers the second protrusion.

3. The cover plate structure according to claim 2, characterized in that, The dimension of the cover plate body in the first direction is T1, wherein 2.0mm≤T1≤2.5mm; The wall thickness of the first boss is T2, where 1.5mm ≤ T2 ≤ 2.0mm; The dimension of the first boss in the first direction is H1, where 0.7 ≤ ≤0.8; The second boss has a dimension H2 in the first direction, where 0.55 ≤ ≤0.75, 2.0mm≤H1+H2≤4.0mm.

4. The cover plate structure according to claim 1, characterized in that, The support plate includes multiple integrally connected support components, each support component having an extending direction, and support protrusions are provided at both ends of the extending direction of each support component. The support component includes a first support bar extending along a second direction and a second support bar extending along a third direction, the second direction and the third direction intersecting each other, and the plane defined by the second direction and the third direction intersecting the first direction.

5. The cover plate structure according to claim 4, characterized in that, The support plate portion further includes reinforcing ribs. Each support component is provided with a plurality of reinforcing ribs. The plurality of reinforcing ribs are spaced apart along the extension direction of the corresponding support component. The reinforcing ribs protrude from the support component along the first direction toward the side opposite to the cover plate body at a predetermined height.

6. The cover plate structure according to claim 5, characterized in that, The dimension of the support member in the direction perpendicular to the extension direction is A3, wherein 8mm≤A3≤13.5mm; And / or, the dimension of the support member in the first direction is t1, wherein 0.8mm≤t1≤1.2mm; And / or, the dimension of the reinforcing rib in the first direction is t2, wherein 0.2mm≤t2≤0.5mm.

7. The cover plate structure according to claim 4, characterized in that, The dimension of the cover plate body in the second direction is A1, wherein 155mm≤A1≤180mm; The dimension of the pole group in the second direction is L1, the dimension of the support assembly in the second direction is A2, and the sum of the dimensions of the support plate in the first direction and the dimensions of the support protrusion in the first direction is H3, wherein 0.35 ≤ ≤0.45; And / or, the dimension of the cover plate body in the third direction is B1, wherein 40mm ≤ B1 ≤ 58mm, and the dimension of the support assembly in the third direction is B2, wherein 5mm ≤ ≤8mm.

8. The cover plate structure according to any one of claims 1 to 7, characterized in that, The effective opening area S0 of the explosion-proof valve, and the end area S1 of the side of the support plate facing the electrode assembly, wherein 1.85 ≤ ≤2.

2.

9. The cover plate structure according to any one of claims 1 to 7, characterized in that, The support assembly further includes an adhesive portion that bonds the support protrusion to the support plate portion.

10. A battery cell, characterized in that, The cover structure includes any one of claims 1 to 9.

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