Battery cell and battery pack

Abstract

The application provides a battery monomer and a battery pack. The battery monomer comprises: an end cover assembly comprising a first wall, wherein the first wall is provided with a pressure relief mechanism; a shell comprising an opening, wherein the end cover assembly covers the opening and forms a connecting structure with the shell; an electrode assembly arranged in a space formed by the shell and the end cover assembly, wherein the first wall faces the electrode assembly; and a support member protruding from the first wall towards the electrode assembly, wherein the support member is used to form an exhaust passage between the electrode assembly and the first wall, and the exhaust passage is communicated with the pressure relief mechanism; wherein, along a first direction, the minimum straight line distance between the center of the support member and the adjacent connecting structure is D1 mm, the straight line distance between the center of the support member and the center of the pressure relief mechanism is D2 mm, and D1 / D2≤0.125 or D1 / D2≥0.2 is satisfied; and the first direction is the direction from the connecting structure to the pressure relief mechanism through the support member. The battery monomer and the battery pack provided by the application have good safety performance.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery cell and a battery pack. Background Technology

[0002] In the development of battery technology, besides improving cell performance, safety is also a crucial issue that cannot be ignored. Therefore, how to enhance cell safety is a pressing technical problem that needs to be solved in battery technology. Summary of the Invention

[0003] In view of this, the purpose of this application is to propose a battery cell and a battery pack to at least partially solve the problem of how to enhance the safety of the battery cell.

[0004] Based on the above objectives, a first aspect of this application provides a battery cell, comprising: an end cap assembly including a first wall, the first wall being provided with a pressure relief mechanism; a housing including an opening, the end cap assembly covering the opening and forming a connection structure with the housing; an electrode assembly disposed within a space enclosed by the housing and the end cap assembly, the first wall facing the electrode assembly; and a support member protruding from the first wall toward the electrode assembly, the support member being used to form an exhaust channel communicating with the pressure relief mechanism between the electrode assembly and the first wall; wherein, along a first direction, the minimum straight-line distance between the center of the support member and the adjacent connection structure is D1mm, and the straight-line distance between the center of the support member and the center of the pressure relief mechanism is D2mm, satisfying: D1 / D2≤0.125, or D1 / D2≥0.20; the first direction is the direction from the connection structure through the support member to the pressure relief mechanism.

[0005] Optionally, the value range of D1 / D2 is 0.01 to 0.125; or, the value range of D1 / D2 is 0.20 to 0.90.

[0006] Optionally, at least a portion of the support member has a melting point greater than 200 degrees Celsius.

[0007] Optionally, the maximum dimension of the support member along the first direction is W1mm, and the value range of W1 / (D1+D2) is less than 0.2.

[0008] Optionally, the support member includes a first surface adjacent to the electrode assembly along the second direction, the area of ​​the first surface being S1mm. 2 The second direction is perpendicular to the first wall; the first wall is divided into two parts arranged along the first direction by the center line of the end cap assembly, wherein the area of ​​the smaller part and the part provided with the support member is S2mm. 2 S1 / S2 > 0.05.

[0009] Optionally, along the second direction, a first groove is formed on the surface of the support member facing the electrode assembly. The first groove extends through the support member along the first direction. The dimension of the first groove along the third direction is L1 mm, and the value of L1 ranges from 0.5 mm to 10 mm. The second direction is perpendicular to the first wall, and the third direction, the second direction, and the first direction are perpendicular to each other.

[0010] Optionally, the support member includes a base, and at least a portion of the surface of the base facing the electrode assembly forms the first surface; the support member satisfies at least one of the following conditions:

[0011] The dimension of the substrate along the first direction is the width of the substrate. Along the third direction, the width of at least a portion of the substrate from its center to a position near its end is smaller than the width of the end of the substrate. The third direction, the second direction, and the first direction are perpendicular to each other. The end of the substrate along the third direction is welded to the first wall via a support leg, forming a weld mark; the weld mark has a dimension of L2mm along the first direction, and the maximum dimension of the support member along the first direction is W1mm, L2 / W1>0.3; the third direction, the second direction, and the first direction are perpendicular to each other.

[0012] Optionally, the support member includes a base and a reinforcing member. Along the second direction, the base is spaced apart from the first wall, and the reinforcing member is disposed between the base and the first wall.

[0013] Optionally, the reinforcing member is connected to the base; a gap is formed between the reinforcing member and the first wall along the second direction.

[0014] Optionally, the area of ​​the orthographic projection of the substrate and the reinforcing member along the second direction is S3mm. 2 The supporting member satisfies at least one of the following conditions: The area of ​​the reinforcing member's orthographic projection along the second direction is S4mm. 2 S4 / S3 > 0.3; The support member has a first groove formed on its surface facing the electrode assembly. The first groove extends through the support member along the first direction, and the area of ​​the orthographic projection of the first groove along the second direction is 5 mm. 2 S5 / S3 > 0.2.

[0015] Optionally, the housing includes two first side plates spaced apart along the first direction; the end cap assembly includes two pole posts insulated from the first wall and spaced apart along the first direction, and the support member is disposed between adjacent first side plates and the pole posts; and / or, The housing also includes two second side plates spaced apart along a third direction, the third direction being perpendicular to the first direction, and the outer surface area of ​​the first side plate being smaller than the outer surface area of ​​the second side plate.

[0016] Optionally, the connection structure is disposed between the first side plate and the end cap assembly; the electrode assembly includes at least two bodies stacked along the third direction, the bodies being a wound structure, and the surface of the bodies facing the first side plate being curved.

[0017] Optionally, the end cap assembly includes an insulating member connected to the first wall, the surface of the insulating member facing the first wall having a second groove for accommodating at least a portion of the support member, such that the support member is disposed between the insulating member and the first wall; the contact area between the insulating member and the first wall is greater than the contact area between the support member and the first wall.

[0018] Based on the same inventive concept, the second aspect of this application also provides a battery pack, including battery cells as described in the first aspect.

[0019] As can be seen from the above, the battery cell and battery pack provided in this application form a connection structure between the casing and the end cap assembly. The first wall of the end cap assembly is provided with a pressure relief mechanism, and the battery cell is also provided with a support member protruding towards the electrode assembly from the first wall. Along the direction from the connection structure through the support member to the pressure relief mechanism, the minimum straight-line distance between the center of the support member and the adjacent connection structure is D1mm, and the straight-line distance between the center of the support member and the center of the pressure relief mechanism is D2mm. Designing D1 and D2 to satisfy: D1 / D2≤0.125, or D1 / D2≥0.20, can alleviate the stress concentration of the connection structure, effectively reduce the risk of cracking in the connection structure, and effectively improve the safety performance of the battery cell.

[0020] At the same time, for battery modules and battery packs that include individual battery cells, it can also prevent non-directional venting of individual battery cells after thermal runaway, reduce the impact on other normal battery cells in the same environment, reduce the risk of large-scale thermal runaway, and help improve the safety performance of battery modules and battery packs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A partial schematic diagram of the first type of battery cell is shown.

[0023] Figure 1a A partial schematic diagram of the battery cell with the second structure is shown.

[0024] Figure 2 The first type of battery cell structure was demonstrated. Figure 1 Partial cross-sectional diagram of section AA; Figure 3 Showing Figure 2 Enlarged schematic diagram of part B; Figure 4 The first type of battery cell structure was demonstrated. Figure 2 Partial cross-sectional view of the CC section; Figure 4a for Figure 4 An enlarged schematic diagram of section E in the middle; Figure 4b The third type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional view of the CC section; Figure 5 The diagram shows the strain optimization effect of the connection structure under different scales in the first set of simulation experiments D1 and D2. Figure 6 The diagram shows the effect of strain optimization on the connection structure under different scales in the second set of simulation experiments D1 and D2. Figure 7 The diagram shows a partial schematic of a single battery cell after thermal runaway and deformation of the end cap assembly. Figure 8 The first type of battery cell structure was demonstrated. Figure 2 Partial cross-sectional diagram of section DD; Figure 9 The fourth type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional view of the DD section; Figure 10 The fourth type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional view of the CC section; Figure 11 The fifth type of battery cell structure was demonstrated. Figure 2A partial cross-sectional view of the CC section; Figure 12 The sixth type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional view of the CC section; Figure 13 A schematic diagram showing the flow of high-temperature gas inside a battery cell is presented.

[0025] Explanation of reference numerals in the attached figures: 100. End cap assembly; 101. Cover plate; 102. Pressure relief mechanism; 103. First wall; 104. Pole post; 105. Insulating component; 1051. Second groove; 1052. Through hole; 200, Shell; 201, Opening; 202, Side plate; 2021, First side plate; 2022, Second side plate; 300. Connection structure; 400. Electrode assembly; 401. Main body; 402. Electrode tab; 500. Supporting component; 501. First surface; 502. First groove; 503. Base; 504. Reinforcing member; 505. Support leg; 506. Weld mark; 507. Gap; 600, exhaust channel; 700, fan-shaped channel. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0027] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0028] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0029] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] Figure 1 This shows a partial schematic diagram of a battery cell with the first structure. Figure 1a A partial schematic diagram of the battery cell with the second structure is shown. Figure 2 The first type of battery cell structure was demonstrated. Figure 1 A partial cross-sectional diagram of section AA.

[0032] like Figure 1 , Figure 1a and Figure 2 The battery cell may include a housing 200, at least one end of which is provided with an opening 201, which may be formed by a side plate 202 for constructing the housing 200. For example, Figure 1 and Figure 2 The shape of opening 201 can be rectangular (including right-angled rectangles and rounded rectangles); for example Figure 1a The shape of opening 201 can also be circular.

[0033] The battery cell also includes an end cap assembly 100 that covers the opening 201. The end cap assembly 100 can be connected to the housing 200 by welding or adhesive. An electrode assembly 400 is disposed within the space formed by the end cap assembly 100 and the housing 200. When the battery cell experiences thermal runaway, high-temperature gas is generated inside the housing 200, increasing the internal pressure. To relieve pressure on the battery cell, the end cap assembly 100 can be equipped with a pressure relief mechanism 102. When the pressure inside the housing 200 exceeds a preset threshold, the pressure relief mechanism 102 opens by at least one method such as breaking, cracking, or flipping. The high-temperature gas inside the housing 200 can then be gradually and directionally discharged to the outside through the opened pressure relief mechanism 102, preventing the battery cell from exploding and improving the safety performance of the battery cell.

[0034] However, when a battery cell experiences thermal runaway, the connection between the end cap assembly 100 and the housing 200 may be torn, causing high-temperature gas to leak through the crack. This means the high-temperature gas will escape in a direction other than the preset one (hereinafter referred to as non-directional venting). In environments with multiple battery cells, such as battery packs, non-directional venting from a thermally runaway battery cell can adversely affect normal battery cells, potentially causing widespread thermal runaway and leading to serious safety accidents.

[0035] In order to investigate the cause of the above problems, the applicant studied the internal structure of the battery cells.

[0036] Figure 3 Showing Figure 2 Enlarged schematic diagram of part B.

[0037] like Figure 2 and Figure 3 In conjunction with the foregoing, after thermal runaway occurs in a single battery cell, high-temperature gas will be rapidly discharged through the activated pressure relief mechanism 102 on the side of the electrode assembly 400 closest to the pressure relief mechanism 102 (hereinafter referred to as the top of the electrode assembly 400); however, on the side of the electrode assembly 400 furthest from the pressure relief mechanism 102 (hereinafter referred to as the bottom of the electrode assembly 400), the high-temperature gas can only flow towards the pressure relief mechanism 102 relatively slowly. This results in a higher pressure at the bottom of the electrode assembly 400 and a lower pressure at the top. Under the pressure difference, the electrode assembly 400 may move towards the pressure relief mechanism 102, compressing the space for the high-temperature gas to flow towards the pressure relief mechanism 102.

[0038] To prevent the aforementioned problems, in some embodiments, a support member 500 is provided between the end cap assembly 100 and the electrode assembly 400 to support and limit the electrode assembly 400, thereby forming an exhaust channel 600 communicating with the pressure relief mechanism 102 between the electrode assembly 400 and the end cap assembly 100. Figure 3 During the flow of the high-temperature gas inside the housing 200, it will bypass the support member 500 and flow to the pressure relief mechanism 102 through the exhaust channel 600.

[0039] However, combined Figure 2 and Figure 3 When the internal pressure of the housing 200 is high, the side plate 202 of the housing 200 will bend outward under pressure, along the height direction (e.g. Figure 2 and Figure 3If the dimension in the Z direction decreases, a downward force will be exerted on the connection between the housing 200 and the end cap assembly 100. If the position of the support member 500 is not designed properly, the end cap assembly 100 will exert an upward force on the connection under the lifting action of the electrode assembly 400 and the support member 500. Under the action of two opposing forces, the connection may tear.

[0040] To avoid the above problems, the location of the support component 500 needs to be designed reasonably.

[0041] Figure 4 The first type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional diagram of the CC section.

[0042] like Figure 2 , Figure 3 and Figure 4 In some embodiments, the battery cell includes: an end cap assembly 100, including a first wall 103, the first wall 103 being provided with a pressure relief mechanism 102; a housing 200, including an opening 201, the end cap assembly 100 covering the opening 201 and forming a connection structure 300 with the housing 200; an electrode assembly 400 disposed within the space enclosed by the housing 200 and the end cap assembly 100, the first wall 103 facing the electrode assembly 400; a support member 500 protruding from the first wall 103 towards the electrode assembly 400, the support member 500 being used to form an exhaust channel 600 communicating with the pressure relief mechanism 102 between the electrode assembly 400 and the first wall 103; wherein, along a first direction (e.g. Figure 4 The minimum straight-line distance between the center of the support member 500 and the adjacent connecting structure 300 is D1mm, and the straight-line distance between the center of the support member 500 and the center of the pressure relief mechanism 102 is D2mm, satisfying: D1 / D2≤0.125, or D1 / D2≥0.20; the first direction is the direction from the connecting structure 300 through the support member 500 to the pressure relief mechanism 102.

[0043] For example, the end cap assembly 100 may include a cover plate 101 and an electrode post 104 insulated from the cover plate 101; the cover plate 101 covers the opening 201, and at least a portion of the surface of the electrode assembly 400 facing it may serve as a first wall 103; the electrode post 104 is connected to the tab 402 of the electrode assembly 400, and the electrode assembly 400 may be electrically connected to an external circuit through the electrode post 104.

[0044] It should be noted that the connection structure 300 refers to the part in direct contact between the housing 200 and the end cap assembly 100 when they are ideally connected (of course, this direct contact includes the case where there is a small amount of adhesive between them).

[0045] For example, the electrode assembly 400 includes a body 401 and tabs 402 extending from the body 401. The body 401 includes a wound body (i.e., a structure formed by winding a positive electrode, a negative electrode, and a separator that isolates the two) or a stacked body (i.e., a structure formed by stacking a positive electrode, a negative electrode, and a separator that isolates the two).

[0046] For example, the support member 500 may be connected to the end cap assembly 100, the housing 200, or the electrode assembly 400.

[0047] For example, when the support member 500 is connected to the first wall 103, the support member 500 and the first wall 103 can be connected by means of integral molding, welding, bonding, hot pressing or snap-fitting.

[0048] For example, the support member 500 can be a column-shaped structure, a C-shaped plate-shaped structure, a Z-shaped plate-shaped structure, or a serpentine plate-shaped structure. When gas passes through the support member 500, it can bypass the solid part of the support member 500.

[0049] For example, D1 / D2 can be 0.11, 0.1, 0.25, 0.26 or 0.08.

[0050] For example, Figure 4b The third type of battery cell structure was demonstrated. Figure 2 A partial sectional view of the CC section. Support member 500, in addition to... Figure 4 In addition to the integrated structure shown, it can also be as follows: Figure 4b The diagram shows a structure consisting of at least two independent and spaced-apart parts.

[0051] For example, when the support member 500 comprises at least two parts, and the at least two parts are positioned differently along the first direction, at least one of the parts constituting the support member 500 satisfies D1 / D2≤0.125 or D1 / D2≥0.20. It should also be noted that the part of the support member 500 that satisfies the above conditions can be aligned with the centerline of the end cap assembly 100 extending along the first direction (e.g., Figure 4b The horizontal dotted lines in the text may or may not intersect.

[0052] It should be noted that the position of the support component 500 should avoid the tab 402 and the pole post 104 to prevent adverse effects on the connection reliability of the tab 402 and the pole post 104.

[0053] As can be seen from the foregoing, the location of the support member 500 forms a local rigid support point for the end cap assembly 100. If the position of the support member 500 is designed according to the value range of D1 / D2 being greater than 0.125 and less than 0.20, it will cause stress concentration in the connecting structure 300. As the weakest part of the structure between the shell 200 and the end cap assembly 100, the connecting structure 300 is prone to cracking and other defects.

[0054] If the position of the support member 500 is designed according to D1 / D2≤0.125, then since the support member 500 is very close to the connecting structure 300, the support member 500 itself will share some of the stress originally borne by the connecting structure 300. Correspondingly, the stress concentration of the connecting structure 300 will be alleviated, which can effectively reduce the risk of cracking.

[0055] If the position of the support member 500 is designed according to D1 / D2≥0.20, then since the support member 500 is far away from the connecting structure 300, the local deformation constraint effect of the support member 500 on the end cap assembly 100 is weakened, the deformation coordination between the end cap assembly 100 and the shell 200 is relatively better, the force transmission is smoother, and the stress concentration of the connecting structure 300 is also alleviated, which can effectively reduce the risk of cracking.

[0056] To verify the effect of designing D1 and D2 as D1 / D2≤0.125 or D1 / D2≥0.20 on reducing stress concentration in the connection structure by 300, the inventors conducted two sets of simulation experiments.

[0057] In the first set of simulation experiments, the total length (dimension along the X direction) of the end cap assembly 100 is 318 mm, the width (dimension along the Y direction) is 72 mm, and the support member 500 is a strip structure extending along the Y direction with a dimension of 16 mm along the X direction.

[0058] Table 1. Strain data of the connection structure of the first set of simulation experiments D1 and D2 at different scales (the total length of cover plate 101 is 318 mm and the width of cover plate 101 is 72 mm).

[0059]

[0060] Figure 5 The diagram shows the effect of 300 strain optimization on the connection structure of the first set of simulation experiments D1 and D2 at different scales.

[0061] Combining Table 1 and Figure 5It can be seen that Examples 1, 2, 5, and 6 satisfy D1 / D2 ≤ 0.125 or D1 / D2 ≥ 0.20; Examples 3 and 4 satisfy the condition that the value of D1 / D2 is greater than 0.125 and less than 0.20. Compared to Example 4, the connection structure 300 in Examples 1, 2, 5, and 6 exhibits smaller strain and a higher strain optimization effect, achieving at least a 15% optimization effect compared to the peak value. Compared to Example 4, the connection structure 300 in Examples 1, 2, 5, and 6 has a lower risk of cracking.

[0062] In the second set of simulation experiments, the total length of the end cap assembly 100 is approximately 284 mm and the width is 72 mm. The support member 500 is a strip structure extending along the Y direction, and its dimension along the X direction is 6 mm.

[0063] Table 2. Strain data of the connection structure of the second set of simulation experiments D1 and D2 at different scales (the total length of cover plate 101 is 284 mm and the width of cover plate 101 is 72 mm).

[0064]

[0065] Figure 6 The diagram shows the effect of 300 strain optimization on the connection structure under different scales in the second set of simulation experiments D1 and D2.

[0066] Combine Table 2 and Figure 6 It can be seen that Examples 7, 8, 11, and 12 satisfy D1 / D2 ≤ 0.125 or D1 / D2 ≥ 0.20; Examples 9 and 10 satisfy the condition that D1 / D2 values ​​are greater than 0.125 and less than 0.20. Compared to Example 10, the connection structure 300 in Examples 7, 8, 11, and 12 exhibits smaller strain and a higher strain optimization effect, achieving an optimization effect of at least 14% compared to the peak value. Compared to Example 10, the connection structure 300 in Examples 7, 8, 11, and 12 has a lower risk of cracking.

[0067] Based on the above two sets of simulation experiments, it can be seen that even for battery cells with different cover plate 101 lengths (the cover plate 101 length in the first group is 318 mm, and the cover plate 101 length in the second group is 284 mm), as long as D1 and D2 satisfy D1 / D2≤0.125 or D1 / D2≥0.20, the strain of the connecting structure 300 can be effectively reduced, thereby reducing the risk of cracking in the connecting structure 300.

[0068] The battery cell provided in this embodiment has a connecting structure 300 between the housing 200 and the end cap assembly 100. A pressure relief mechanism 102 is provided on the first wall 103 of the end cap assembly 100. The battery cell also has a support member 500 protruding from the first wall 103 toward the electrode assembly 400. Along the direction from the connecting structure 300 through the support member 500 to the pressure relief mechanism 102, the minimum straight-line distance between the center of the support member 500 and the adjacent connecting structure 300 is D1 mm, and the straight-line distance between the center of the support member 500 and the center of the pressure relief mechanism 102 is D2 mm. Designing D1 and D2 to satisfy: D1 / D2≤0.125, or D1 / D2≥0.20, can alleviate the stress concentration in the connecting structure 300, effectively reduce the risk of cracking in the connecting structure 300, and effectively improve the safety performance of the battery cell.

[0069] At the same time, for battery modules and battery packs that include individual battery cells, it can also prevent non-directional venting of individual battery cells after thermal runaway, reduce the impact on other normal battery cells in the same environment, reduce the risk of large-scale thermal runaway, and help improve the safety performance of battery modules and battery packs.

[0070] In some embodiments, the value of D1 / D2 ranges from 0.01 to 0.125.

[0071] Based on the foregoing, D1 / D2 ≤ 0.125. However, if D1 / D2 is too small, the dimension of the support member 500 along the first direction will be too small, potentially leading to insufficient structural strength. The support member 500 may easily deform after being compressed by the electrode assembly 400, failing to provide stable and reliable support. This increases the risk of the exhaust channel 600 being compressed or even blocked by the electrode assembly 400. If the exhaust channel 600 is blocked, the high-temperature gas inside the battery cell cannot escape smoothly. As the internal pressure of the battery cell gradually increases, the risk of cracking in the connection structure 300 also rises.

[0072] To avoid the above problems, this embodiment designs the value range of D1 / D2 to be 0.01 to 0.125, which can ensure that the support member 500 has sufficient structural strength to support the electrode assembly 400, so as to ensure that the electrode assembly 400 can be stably and reliably supported when the battery cell experiences thermal runaway, so that the exhaust channel 600 can continuously supply high-temperature gas to flow smoothly, and can effectively and timely depressurize the battery cell, thereby reducing the risk of cracking of the connection structure 300.

[0073] In some embodiments, the value of D1 / D2 ranges from 0.20 to 0.90.

[0074] As mentioned above, D1 / D2 ≥ 0.20. However, if D1 / D2 is too large, the distance between the support member 500 and the pressure relief mechanism 102 along the first direction will be too small. As also mentioned above, the end cap assembly 100 needs to be equipped with a pole post 104 connected to the pole tab 402. If the distance between the support member 500 and the pressure relief mechanism 102 is too small, it will be difficult to provide sufficient space for the pole post 104 in the first wall 103, posing a risk that at least one of the pole post 104 and the pole tab 402 will interfere with the support member 500.

[0075] To avoid the above problems, this embodiment designs the value range of D1 / D2 to be 0.20 to 0.90. While effectively reducing the risk of cracking of the connection structure 300, it can also provide sufficient space for the pole post 104 in the first wall 103. This can effectively reduce the risk of interference between at least one of the pole post 104 and the tab 402 and the support member 500, and help ensure a reliable connection between the pole post 104 and the tab 402, thereby improving the electrical performance of the battery cell.

[0076] In some embodiments, at least a portion of the support member 500 has a melting point greater than 200 degrees Celsius.

[0077] For example, at least a portion of the support member 500 may be provided with a heat-resistant insulating element, such that the melting point of the region of the support member 500 with the heat-resistant insulating element is greater than 200 degrees Celsius. For instance, the support member 500 may include a non-insulating structure, and the heat-resistant insulating element may be a film structure or block structure formed of polyimide (PI) material, connected to the non-insulating structure in the support member 500 by means of winding, hot pressing, adhesive bonding, snap-fitting, fasteners, or fitting. In this case, the support member 500 can support the electrode assembly 400 through the heat-resistant insulating element. Since the support member 500 can be insulated from the electrode assembly 400 through the heat-resistant insulating element, no other insulating material structure is required between the support member 500 and the electrode assembly 400.

[0078] For example, the support member 500 may be formed of a heat-resistant insulating material.

[0079] Understandably, after a battery cell experiences thermal runaway, its internal temperature becomes high. If the overall melting point of the support component 500 is too low, its structural strength will decrease in a high-temperature environment, and it may even melt. At this time, the support component 500 is prone to deformation after being squeezed by the electrode assembly 400, and cannot provide stable and reliable support for the electrode assembly 400. There is a high risk that the exhaust channel 600 will be compressed or even blocked by the electrode assembly 400. If the exhaust channel 600 is blocked, the high-temperature gas inside the battery cell cannot be discharged smoothly. As the internal pressure of the battery cell gradually increases, the risk of cracking of the connection structure 300 also increases.

[0080] To avoid the aforementioned problems, this embodiment designs at least a portion of the melting point of the support member 500 to be greater than 200 degrees Celsius. This ensures that the support member 500 maintains sufficient structural strength to support the electrode assembly 400 even in high-temperature environments. In the event of thermal runaway in a single battery cell, the support member 500 can provide stable and reliable support to the electrode assembly 400, allowing for a continuous and smooth flow of high-temperature gas through the exhaust channel 600. This enables timely and effective depressurization of the battery cell, reducing the risk of cracking in the connection structure 300.

[0081] like Figure 4 In some embodiments, the maximum dimension of the support member 500 along the first direction is W1mm, and the value of W1 / D1+D2 is less than 0.2.

[0082] It should be noted that for different parts of the support member 500 along the Y direction, the dimensions of each part along the first direction can be the same or different. When the dimensions are different, W1 is the largest dimension among these dimensions.

[0083] For example, W1 / D1+D2 can be 0.19, 0.18, 0.17, 0.16 or 0.15.

[0084] Figure 7 The diagram shows a partial schematic of a single battery cell after thermal runaway and deformation of the end cap assembly 100.

[0085] like Figure 3 and Figure 4 Due to the limited space for the first wall 103, the size of the outlet for gas passage formed by the pressure relief mechanism 102 after it is opened is not very large. In other words, some gas will still remain at the top of the electrode assembly 400, waiting to be discharged through the pressure relief mechanism 102. Figure 7 Under the pressure of this gas, the end cap assembly 100 will deform, causing the first wall 103 to become a curved surface. Among them, the area corresponding to D1 is smaller, and the degree of curvature is correspondingly smaller; while the area corresponding to D2 is larger, and the degree of curvature is correspondingly larger.

[0086] When the support member 500 is connected to the first wall 103, a portion of the support member 500 is connected to the part corresponding to D1, and another portion is connected to the part corresponding to D2. If W1 / D1+D2 is too large, then the contact area between the support member 500 and the first wall 103 is too large, and the impact of the deformation of the first wall 103 on it is also too large. After the first wall 103 bends and deforms, the support member 500 may undergo a large degree of deformation, flip with the first wall 103, or separate from the first wall 103 and move with the flowing high-temperature gas. These may cause the limiting function of the support member 500 on the electrode assembly 400 to fail, thereby causing the electrode assembly 400 to move toward the end cap assembly 100, hindering the flow of high-temperature gas to the pressure relief mechanism 102, and further accelerating the runaway of the battery cell.

[0087] To avoid the aforementioned problems, this embodiment designs the value range of W1 / D1+D2 to be less than 0.2. Therefore, the contact area between the support member 500 and the first wall 103 is smaller, and the impact of deformation of the first wall 103 on the support member 500 is correspondingly less. Even if the first wall 103 undergoes compressive deformation, the support member 500 can still provide a stable and reliable limiting effect on the electrode assembly 400, ensuring that high-temperature gas can flow smoothly through the exhaust channel 600 to the pressure relief mechanism 102 and be discharged, effectively improving the safety performance of the battery cell.

[0088] Figure 8 The first type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional diagram of the DD section.

[0089] like Figure 4 and Figure 8 In some embodiments, the support member 500 includes a second direction (e.g., Figure 8 The first surface 501 (in the Z direction) adjacent to the electrode assembly 400 has an area of ​​S1mm. 2 The second direction is perpendicular to the first wall 103; the first wall 103 is divided into two parts arranged along the first direction by the center line of the end cap assembly 100, wherein the area of ​​the smaller part, which is provided with the support member 500, is S2mm. 2 S1 / S2 > 0.05.

[0090] For example, the first surface 501 can be a continuous surface, or the first surface 501 can include multiple spaced-apart regions; when the first surface 501 includes multiple spaced-apart regions, S1 is the total area of ​​these regions. Specifically, Figure 9 The fourth type of battery cell structure was demonstrated. Figure 2 Partial cross-sectional diagram of the DD section. Figure 10 The fourth type of battery cell structure was demonstrated. Figure 2A partial cross-sectional diagram of the CC section. (See diagram below.) Figure 9 and Figure 10 When the support member 500 is arranged in a serpentine shape, the first surface 501 will be recessed and divided into multiple spaced areas.

[0091] For example, the center of the end cap assembly 100 may coincide with the center of the first wall 103, then the two parts of the first wall 103 divided by the center line of the end cap assembly 100 have the same area, both being S2.

[0092] For example, S1 / S2 can be 0.055, 0.06, 0.065, 0.07 or 0.075.

[0093] If S1 / S2 is too small, the contact area between the support member 500 and the electrode assembly 400 will be too small. When the support member 500 is squeezed by the electrode assembly 400, a high local pressure will be formed, resulting in stress concentration. The concentrated stress will be transmitted to the end cap assembly 100 through the support member 500, which can easily cause a large degree of deformation or generate large bending stress on the end cap assembly 100. This concentrated stress will then be transmitted to the connecting structure 300, leading to a higher risk of cracking in the connecting structure 300.

[0094] To avoid the above problems, in this embodiment, S1 and S2 are designed to be S1 / S2 > 0.05. This results in a larger contact area between the support member 500 and the electrode assembly 400, a smaller local pressure on the support member 500 when it is squeezed by the electrode assembly 400, and a smaller stress ultimately transmitted to the connecting structure 300. This can effectively reduce the risk of cracking in the connecting structure 300.

[0095] like Figure 9 and Figure 10 In some embodiments, along the second direction, a first groove 502 is formed on the surface of the support member 500 facing the electrode assembly 400. The first groove 502 penetrates the support member 500 along the first direction, and the first groove 502 extends along a third direction (e.g., along the second direction). Figure 9 and Figure 10 The dimension of the Y direction is L1mm, and the value of L1 ranges from 0.5mm to 10mm; the third direction, the second direction and the first direction are perpendicular to each other.

[0096] For example, the first groove 502 can be formed by removing material from the support member 500, or by stamping or other means.

[0097] For example, L1 can be 0.5 mm, 2.5 mm, 5 mm, 7.5 mm or 10 mm.

[0098] It should be noted that, at least in this embodiment, the surface of the support member 500 facing the electrode assembly 400 includes two parts: one part is the bottom of the first groove 502, and the other part is the area where the first groove 502 is not provided. The bottom of the first groove 502 does not constitute the first surface 501 of the support member 500.

[0099] A first groove 502 extending along the first direction is provided in the support member 500. When high-temperature gas passes through, it can pass through the support member 500 through the first groove 502, which helps to increase the effective cross-sectional area of ​​the exhaust channel 600 and facilitates the smooth flow of high-temperature gas inside the shell 200.

[0100] It should be noted that thin aluminum foil can be used to form the positive electrode of the electrode assembly 400. When a single battery cell experiences thermal runaway, the internal temperature of the battery will exceed the melting point of aluminum (approximately 660°C). At this time, the thin aluminum foil will begin to melt and produce aluminum beads. The aluminum beads are in a free state and have a certain volume. If large aluminum beads are allowed to flow in the exhaust channel 600, they may block the exhaust channel 600.

[0101] When a first groove 502 extending in the first direction is formed on the surface of the support member 500 facing the electrode assembly 400, not only can high-temperature gas pass through the first groove 502, but aluminum molten beads can also pass through the first groove 502 under the influence of the high-temperature gas. If L1 is too large, then large aluminum molten beads can pass through the first groove 502 and move towards the pressure relief mechanism 102, easily causing blockage of the exhaust channel 600. If L1 is too small, then the first groove 502 is more easily blocked by aluminum molten beads, also easily causing blockage of the exhaust channel 600.

[0102] To avoid the above problems, this embodiment designs the value range of L1 to be 0.5mm to 10mm, which can intercept the large aluminum molten beads and prevent them from passing through the support member 500 through the first groove 502 and moving towards the pressure relief mechanism 102. Furthermore, since the size of the first groove 502 is large enough, even if part of the first groove 502 is blocked by the aluminum molten beads, the remaining part can still allow the high-temperature gas to flow smoothly, which helps to reduce the risk of blockage in the exhaust channel 600 and ensures that the high-temperature gas can flow smoothly through the exhaust channel 600 to the pressure relief mechanism 102 and be discharged in a timely manner.

[0103] Figure 4a for Figure 4 An enlarged schematic diagram of section E in the middle.

[0104] like Figure 4 , Figure 4a , Figure 8 and Figure 9In some embodiments, the support member 500 includes a base 503, on the surface of the base 503 facing the electrode assembly 400, at least a portion of which forms a first surface 501; the end of the base 503 along a third direction is welded to a first wall 103 via a foot 505, forming a solder mark 506; the solder mark 506 has a dimension of L2mm along the first direction, and L2 / W1 > 0.3.

[0105] For example, the base 503 and the support 505 can be connected by welding, snap-fitting, bonding or integral molding.

[0106] It should be noted that, for Figure 9 The structure shown has a curved serpentine structure between the two legs 505, wherein a flat plate-like structure near the electrode assembly 400 forms a base 503, and a portion protruding toward the first wall 103 divides the base 503 into multiple regions.

[0107] When a single battery cell experiences thermal runaway, the substrate 503 comes into direct contact with the electrode assembly 400. To achieve the function of limiting the electrode assembly 400, it is necessary to prevent the substrate 503 from moving significantly towards the first wall 103. Therefore, for the strip-shaped substrate 503 extending along a third direction, support legs 505 are provided at both ends of the substrate 503 to limit and support the ends of the substrate 503, helping to keep the substrate 503 in its original position and thus achieving the function of limiting the electrode assembly 400.

[0108] For example, L2 / W1 can be 0.31, 0.32, 0.33, 0.34 or 0.35.

[0109] If L2 / W1 is too small, the length of the solder mark 506 will be too small, resulting in low structural strength. In conjunction with the above, when the first wall 103 bends, the solder mark 506 may crack under stress, causing the welding between the support leg 505 and the first wall 103 to fail. The support member 500 is prone to movement or flipping, making it difficult to achieve a stable and reliable limiting effect on the electrode assembly 400.

[0110] To avoid the aforementioned problems, this embodiment designs L2 and W1 as L2 / W1 > 0.3. This allows for a larger solder joint 506 length and higher structural strength, which helps improve the connection reliability between the support leg 505 and the first wall 103, preventing the support member 500 from moving or flipping, and ensuring a stable and reliable limiting effect on the electrode assembly 400. The larger the value of L2 / W1, the more obvious the above effect. Even if L2 / W1 equals 1, it will not adversely affect the connection reliability between the support member 500 and the first wall 103.

[0111] Figure 11 The fifth type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional diagram of the CC section. Figure 12 The sixth type of battery cell structure was demonstrated. Figure 2 A partial cross-sectional diagram of the CC section.

[0112] like Figure 11 and Figure 12 In some embodiments, the dimension of the substrate 503 along the first direction is the width of the substrate 503; along the third direction, the width of at least a portion of the substrate 503 from the center to a position near the end is smaller than the width of the end of the substrate 503.

[0113] It should be noted that, with Figure 12 Taking the structure shown as an example, the horizontal dotted line in the figure is the center line of the end cap assembly 100 extending along the first direction, which passes through the center of the base 503 along the third direction.

[0114] For example, in the base 503, the portion smaller than the end width can be of equal width or have a gradually changing width (e.g., Figure 11 ), or the width varies in a stepped manner (such as Figure 12 ).

[0115] like Figure 3 and Figure 4 When a single battery cell experiences thermal runaway, the first surface 501 of the substrate 503 comes into contact with the top of the main body 401 of the electrode assembly 400. Since the top of the main body 401 includes gaps between the positive and negative electrode plates, high-temperature gas can flow along these gaps to the exhaust channel 600. If the area of ​​the first surface 501 of the substrate 503 is too large, it will block too many of these gaps, hindering the flow of gas. However, as can be seen from the foregoing, if the overall width of the first surface 501 is too small, it will lead to excessive pressure on the supporting member 500.

[0116] To avoid the aforementioned problems, this embodiment only reduces the width of a portion of the substrate 503. For example... Figure 11 The portion of the substrate 503 located near the center along a third direction can be designed as a region with a smaller width; or, as... Figure 12 The portion of the substrate 503 near the end along a third direction can be designed as a region with a smaller width.

[0117] It should also be noted that, taking the wound body as an example, in the event of thermal runaway, the total amount of high-temperature gas generated in the inner ring will be greater than the total amount of high-temperature gas generated in the outer ring. Therefore, in this embodiment, the area near the center of the substrate 503 is designed to be a narrower area, which ensures that the inner ring of the body 401 corresponds to the narrower area of ​​the substrate 503, providing more space for gas flow.

[0118] like Figure 8 and Figure 9 In some embodiments, the support member 500 includes a base 503 and a reinforcing member 504. Along the second direction, the base 503 is spaced apart from the first wall 103, and the reinforcing member 504 is disposed between the base 503 and the first wall 103.

[0119] For example, the reinforcement 504 can be connected to the base 503 or to the first wall 103.

[0120] For example, when the reinforcing member 504 is connected to the base 503, the connection can be achieved by welding, snap-fitting, bonding or integral molding; similarly, when the reinforcing member 504 is connected to the first wall 103, the connection can also be achieved by at least one of the above methods.

[0121] For example, for Figure 8 In the structure shown, the reinforcing member 504 and the base 503 can be independent of each other and connected, or they can be integrally formed and connected.

[0122] It should be noted that, for Figure 9 The structure shown has a curved, serpentine shape between the two legs 505, with the portion protruding towards the first wall 103 forming a reinforcing member 504. Simultaneously, a recess is formed on the side of the protrusion away from the first wall 103, which can form a first groove 502.

[0123] When a single battery cell experiences thermal runaway, the substrate 503 comes into direct contact with the electrode assembly 400. To achieve the function of limiting the electrode assembly 400, it is necessary to prevent the substrate 503 from deforming significantly towards the first wall 103. Therefore, for the strip-shaped substrate 503 extending along a third direction, supports 505 are provided at both ends of the substrate 503 to support and fix the ends of the substrate 503. For the middle part of the substrate 503, a reinforcing member 504 can be provided. When the middle part of the substrate 503 tends to move or deform towards the first wall 103, the reinforcing member 504 can reliably support the substrate 503, helping to keep the substrate 503 in its original position and thus achieving the function of limiting the electrode assembly 400.

[0124] like Figure 8 and Figure 9 In some embodiments, the reinforcing member 504 is connected to the base 503, and a gap 507 is formed between the reinforcing member 504 and the first wall 103 along the second direction.

[0125] In this embodiment, when the support leg 505 is welded to the first wall 103, a gap 507 is formed between the reinforcing member 504 and the first wall 103 (i.e., they do not contact each other). This ensures that the support leg 505 and the first wall 103 are in close contact, preventing defects such as incomplete welds or weld spatters. This helps improve the welding quality between the support leg 505 and the first wall 103, ensuring a stable and reliable connection between the support member 500 and the first wall 103. Simultaneously, high-temperature gas can also pass through the support member 500 via the gap 507, ensuring that the high-temperature gas flows smoothly through the exhaust channel 600 to the pressure relief mechanism 102 and is discharged, effectively improving the safety performance of the battery cell.

[0126] like Figure 4 and Figure 10 In some embodiments, the area of ​​the orthographic projection of the substrate 503 and the reinforcing member 504 along the second direction is S3mm. 2 The area of ​​the reinforcing member 504 projected along the second direction is S4mm. 2 S4 / S3 > 0.3.

[0127] It should be noted that, as Figure 4 When the support member 500 is provided with a reinforcing member 504, S4 can be Figure 4 The area within the dashed box. For example... Figure 10 When the support member 500 is provided with two reinforcing members 504, S4 is the sum of the orthographic projection areas of the two reinforcing members 504, that is, S4 can be... Figure 10 The sum of the area between the two upper dashed lines and the area between the two lower dashed lines.

[0128] like Figure 4 When the orthographic projection of the reinforcing member 504 is located inside the orthographic projection of the base 503, S3 is the area of ​​the orthographic projection of the base 503. For example... Figure 10 When the orthographic projection of the reinforcing member 504 and the orthographic projection of the base 503 partially coincide (the part between the dashed line and the adjacent solid line is the overlapping part), S3 is the sum of the area of ​​the orthographic projection of the base 503 and the area of ​​the non-overlapping part (i.e. the part between the two solid lines) in the orthographic projection of the reinforcing member 504.

[0129] For example, S4 / S3 can be 0.31, 0.32, 0.33, 0.34 or 0.35.

[0130] If S4 / S3 is too small, the contact area between the support member 500 and the first wall 103 will be small, and the reinforcing member 504 will easily flip or deform under pressure, making it difficult to provide stable and reliable support for the base 503.

[0131] To avoid the above problems, in this embodiment, S4 and S3 are designed such that S4 / S3 > 0.3, which can make the contact area between the support member 500 and the first wall 103 larger. The reinforcing member 504 can provide stable and reliable support for the electrode assembly 400 through the base 503, and ensure that the exhaust channel 600 between the electrode assembly 400 and the first wall 103 remains unobstructed.

[0132] like Figure 10 In some embodiments, the area of ​​the orthographic projection of the first groove 502 along the second direction is S5mm. 2 S5 / S3 > 0.2.

[0133] It should be noted that, Figure 10 In the structure shown, there are two first grooves 502. The area of ​​the orthographic projection of each first groove 502 is the area of ​​the part between two adjacent grooves. S5 is the sum of the areas of the orthographic projections of the two first grooves 502.

[0134] For example, S5 / S3 can be 0.21, 0.22, 0.23, 0.24 or 0.25.

[0135] When the support member 500 is provided with the first groove 502, if S5 / S3 is too small, only a small amount of gas can pass through the first groove 502, which is not conducive to the smooth flow of gas in the exhaust channel 600.

[0136] To avoid the above problems, in this embodiment, S5 and S3 are designed such that S5 / S3 > 0.2, which can effectively increase the gas flow rate through the first groove 502 and facilitate the smooth flow of gas in the exhaust channel 600.

[0137] like Figure 1 and Figure 11 In some embodiments, the housing 200 includes two first side plates 2021 spaced apart along a first direction; the end cap assembly 100 includes two pole posts 104 insulated from the first wall 103 and spaced apart along the first direction, and a support member 500 is disposed between adjacent first side plates 2021 and pole posts 104.

[0138] For example, the electrode assembly 400 has a tab 402 including a positive tab and a negative tab, one of the two posts 104 is connected to the positive tab as the positive electrode of the battery cell, and the other is connected to the negative tab as the negative electrode of the battery cell.

[0139] by Figure 11 Taking the structure and orientation shown as an example, the support member 500 on the left is located between the first side plate 2021 on the left and the pole post 104 on the left, and the support member 500 on the right is located between the first side plate 2021 on the right and the pole post 104 on the right.

[0140] For example, the pressure relief mechanism 102 is disposed between the two poles 104.

[0141] Based on the foregoing, compared to the pressure relief mechanism 102, the support member 500 needs to be positioned closer to the housing 200. If the support member 500 is positioned along the first direction on the side of the pole post 104 away from the first side plate 2021, then on the one hand, the position of the support member 500 will not meet the condition D1 / D2≤0.125 or D1 / D2≥0.20. On the other hand, the space between the support member 500 and the first side plate 2021 will be insufficient to accommodate the pole post 104, or there is a risk that the support member 500 will interfere with the tab 402 connected to the pole post 104.

[0142] To avoid the aforementioned problems, in this embodiment, the support member 500 is positioned between the adjacent first side plate 2021 and the pole post 104. This allows for a smaller spacing between the support member 500 and the first side plate 2021, satisfying D1 / D2≤0.125 or D1 / D2≥0.20. Simultaneously, when the support member 500 is close to the first side plate 2021, there is sufficient space on the side of the support member 500 away from the first side plate 2021 for mounting the pole post 104, effectively reducing the risk of interference between the support member 500 and the tab 402 connected to the pole post 104.

[0143] like Figure 1 and Figure 11 In some embodiments, the housing 200 further includes two second side plates 2022 spaced apart along a third direction, the third direction being perpendicular to the first direction, and the outer surface area of ​​the first side plate 2021 being smaller than the outer surface area of ​​the second side plate 2022.

[0144] For example, two first side plates 2021 and two second side plates 2022 together form an opening 201.

[0145] In this embodiment, the orthographic projection of the end cap assembly 100 along the second direction is a rectangle, where the first direction is the length direction of the rectangle and the third direction is the width direction of the rectangle. Since the gap between the electrode post 104 and the corresponding connection structure 300 of the first side plate 2021 is relatively large along the first direction, placing the support member 500 between the adjacent first side plate 2021 and electrode post 104 along the first direction can further prevent the support member 500 from causing interference or other adverse effects on the connection structure 300, electrode tab 402, or electrode post 104, thus helping to improve the electrical performance of the battery cell.

[0146] like Figure 1 and Figure 11In some embodiments, the connection structure 300 is disposed between the first side plate 2021 and the end cap assembly 100, and the electrode assembly 400 includes at least two bodies 401 stacked along a third direction. The bodies 401 are wound structures, and the surfaces of the bodies 401 facing the first side plate 2021 are curved.

[0147] like Figure 11 and Figure 3 For the main body 401 of the winding structure, its end along the first direction is arc-shaped, which allows a fan-shaped channel 700 to be formed between the ends of two adjacent main bodies 401 and the first side plate 2021.

[0148] Figure 13 A schematic diagram showing the flow of high-temperature gas inside a battery cell is presented.

[0149] like Figure 11 and Figure 13 Because of the large cross-sectional area of ​​the fan-shaped channel 700, most of the high-temperature gas accumulated at the bottom of the electrode assembly 400 can flow quickly to the exhaust channel 600 through the fan-shaped channel 700, and then flow to the pressure relief mechanism 102 after passing through the support member 500; a small part of the high-temperature gas flows to the exhaust channel 600 through the gap between the second side plate 2022 and the electrode assembly 400.

[0150] The applicant's research found that although the fan-shaped channel 700 can increase the gas flow velocity from the bottom to the top of the electrode assembly 400, thereby quickly reducing the pressure difference between the top and bottom of the electrode assembly 400 and helping to reduce the risk to the support member 500 from the electrode assembly 400, the connection point between the first side plate 2021 and the end cap assembly 100 is subjected to greater gas impact, and there is also a risk of cracking under the impact of gas.

[0151] To address the aforementioned issues, this embodiment designs the relative positions of the connecting structure 300, the supporting member 500, and the pressure relief mechanism 102 corresponding to the first side plate 2021. Specifically, D1 and D2 are designed such that D1 / D2≤0.125 or D1 / D2≥0.20, effectively reducing the stress transmitted by the supporting member 500 to the connecting structure 300 corresponding to the first side plate 2021. Thus, even if the connecting structure 300 corresponding to the first side plate 2021 is subjected to significant gas impact, it is less prone to cracking, effectively improving the safety performance of the battery cell.

[0152] like Figure 3 and Figure 8In some embodiments, the end cap assembly 100 includes an insulating member 105 connected to the first wall 103. The surface of the insulating member 105 facing the first wall 103 is provided with a second groove 1051 for receiving at least a portion of the support member 500 so that the support member 500 is disposed between the insulating member 105 and the first wall 103. The contact area between the insulating member 105 and the first wall 103 is greater than the contact area between the support member 500 and the first wall 103.

[0153] For example, the insulating element 105 can be connected to the first wall 103 by means of bonding, heat fusion or snap-fit.

[0154] For example, the material of the support member 500 has a higher melting point than the material of the insulating member 105.

[0155] For example, no other structural components may be provided between the support member 500 and the insulating member 105; or, the aforementioned heat-resistant insulating member may be provided between the support member 500 and the insulating member 105.

[0156] It should be noted that the insulating member 105 is disposed between the supporting member 500 and the electrode assembly 400, and between the first wall 103 and the electrode assembly 400, and can be used to insulate the electrode assembly 400 from the cover plate 101. Figure 3 The two side walls of the second groove 1051, which are spaced apart along the first direction, can be provided with through holes 1052 so that gas can enter and exit the second groove 1051 through the through holes 1052.

[0157] In the initial stage of thermal runaway in a single battery cell, before the insulating component 105 melts due to the high temperature inside the casing 200, the insulating component 105 can limit the electrode assembly 400 before the supporting component 500. Combined with... Figure 3 It can be understood that the contact area between the insulating member 105 and the first wall 103 is larger than that between the supporting member 500 and the first wall 103. Therefore, when the electrode assembly 400 presses the first wall 103 through the insulating member 105, the first wall 103 is subjected to more uniform force, and the initial stress on the first wall 103 can be balanced by the insulating member 105.

[0158] Based on the same inventive concept and in conjunction with the description of the battery cells in the above embodiments, this embodiment provides a battery pack that has the corresponding technical effects of the battery cells in the above embodiments, which will not be repeated here.

[0159] This embodiment provides a battery pack, including battery cells as described in the above embodiments.

[0160] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0161] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0162] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0163] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0164] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0165] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: An end cap assembly includes a first wall, the first wall being provided with a pressure relief mechanism; A housing includes an opening, and an end cap assembly covers the opening and forms a connection structure with the housing; an electrode assembly is disposed within the space enclosed by the housing and the end cap assembly, and the first wall faces the electrode assembly; A support member protrudes toward the electrode assembly from the first wall, the support member being used to form an exhaust channel communicating with the pressure relief mechanism between the electrode assembly and the first wall; Wherein, along the first direction, the minimum straight-line distance between the center of the support member and the adjacent connecting structure is D1mm, and the straight-line distance between the center of the support member and the center of the pressure relief mechanism is D2mm, satisfying: D1 / D2≤0.125, or D1 / D2≥0.20; the first direction is the direction from the connecting structure through the support member to the pressure relief mechanism.

2. The battery cell according to claim 1, characterized in that, The value range of D1 / D2 is 0.01 to 0.125; or, the value range of D1 / D2 is 0.20 to 0.

90.

3. The battery cell according to claim 1, characterized in that, At least a portion of the support member has a melting point greater than 200 degrees Celsius.

4. The battery cell according to claim 1, characterized in that, The maximum dimension of the support member along the first direction is W1mm, and the value range of W1 / (D1+D2) is less than 0.

2.

5. The battery cell according to claim 1, characterized in that, The support member includes a first surface adjacent to the electrode assembly along a second direction, the area of ​​the first surface being S1mm. 2 The second direction is perpendicular to the first wall; the first wall is divided into two parts arranged along the first direction by the center line of the end cap assembly, wherein the area of ​​the smaller part and the part provided with the support member is S2mm. 2 S1 / S2 > 0.

05.

6. The battery cell according to claim 5, characterized in that, Along the second direction, a first groove is formed on the surface of the support member facing the electrode assembly. The first groove extends through the support member along the first direction. The dimension of the first groove along the third direction is L1 mm, and the value of L1 ranges from 0.5 mm to 10 mm. The second direction is perpendicular to the first wall, and the third direction, the second direction, and the first direction are perpendicular to each other.

7. The battery cell according to claim 5, characterized in that, The support member includes a base, and at least a portion of the surface of the base facing the electrode assembly forms the first surface; the support member satisfies at least one of the following conditions: The dimension of the substrate along the first direction is the width of the substrate. Along the third direction, the width of at least a portion of the substrate from its center to a position near its end is smaller than the width of the end of the substrate. The third direction, the second direction, and the first direction are perpendicular to each other. The end of the substrate along the third direction is welded to the first wall via a support leg, forming a weld mark; the weld mark has a dimension of L2mm along the first direction, and the maximum dimension of the support member along the first direction is W1mm, L2 / W1>0.3; the third direction, the second direction, and the first direction are perpendicular to each other.

8. The battery cell according to claim 1, characterized in that, The supporting member includes a base and a reinforcing member. Along the second direction, the base is spaced apart from the first wall, and the reinforcing member is disposed between the base and the first wall.

9. The battery cell according to claim 8, characterized in that, The reinforcing member is connected to the base; a gap is formed between the reinforcing member and the first wall along the second direction.

10. The battery cell according to claim 8, characterized in that, The area of ​​the orthographic projection of the substrate and the reinforcing member along the second direction is S3mm. 2 The supporting member satisfies at least one of the following conditions: The area of ​​the reinforcing member's orthographic projection along the second direction is S4mm. 2 S4 / S3 > 0.3; The support member has a first groove formed on its surface facing the electrode assembly. The first groove extends through the support member along the first direction, and the area of ​​the orthographic projection of the first groove along the second direction is 5 mm. 2 S5 / S3 > 0.

2.

11. The battery cell according to claim 1, characterized in that, The housing includes two first side plates spaced apart along the first direction; The end cap assembly includes two pole posts insulated from the first wall and spaced apart along the first direction; the support member is disposed between adjacent first side plates and the pole posts; and / or, The housing also includes two second side plates spaced apart along a third direction, the third direction being perpendicular to the first direction, and the outer surface area of ​​the first side plate being smaller than the outer surface area of ​​the second side plate.

12. The battery cell according to claim 11, characterized in that, The connection structure is disposed between the first side plate and the end cap assembly; the electrode assembly includes at least two main bodies stacked along the third direction, the main body is a wound structure, and the surface of the main body facing the first side plate is curved.

13. The battery cell according to claim 1, characterized in that, The end cap assembly includes an insulating member connected to the first wall. A second groove is provided on the surface of the insulating member facing the first wall. The second groove is used to receive at least a portion of the support member so that the support member is disposed between the insulating member and the first wall. The contact area between the insulating member and the first wall is greater than the contact area between the support member and the first wall.

14. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1 to 13.

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