Secondary battery and battery pack
By optimizing the distance and angle design between the adapter plate and the housing flange, the balance between the welding position and the housing wall distance was solved, enabling rapid pressure relief and improved safety of the battery under thermal runaway conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2026-03-13
Smart Images
Figure CN223993379U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery cell structure technology, and in particular to a secondary battery and battery pack. Background Technology
[0002] The negative electrode adapter is welded to the steel casing, making the steel casing the current conduction path for the battery's negative electrode. This directly affects the stability and safety of the battery's internal circuitry. When there are significant fluctuations in the welding position, the distance between the welding point and the casing wall directly impacts the cell's nail penetration test pass rate and pressure relief performance. According to experimental results, the closer the welding point is to the casing wall, the higher the nail penetration pass rate. To increase the pass rate from approximately 40% to approximately 100%, the distance between the welding point and the casing wall needs to be reduced from approximately 2.0 mm to approximately 0.5 mm. Simultaneously, when the welding point is closer to the casing wall, the adapter opens under less pressure, which facilitates rapid pressure relief during thermal runaway, thereby reducing the internal temperature and pressure of the cell, delaying the chain reaction of thermal runaway in adjacent cells, and ultimately improving the nail penetration test pass rate.
[0003] However, during cell assembly, the pin structure of the adapter piece near the shell wall has a rolled edge. To avoid interference, a gap needs to be left between it and the shell wall. Furthermore, the shell wall and adapter piece are encapsulated through a roller grooving process. When excessively pursuing a close proximity between the welding position and the shell wall, the rolled edge of the adapter piece's pin structure can increase the gap between them. An excessively large gap hinders the stable connection between the adapter piece and the shell wall during welding, weakening the bonding strength of the weld interface and potentially leading to desoldering. Therefore, the distance between the welding position and the shell wall needs to be balanced between mechanical performance and thermal safety performance.
[0004] Increasing the spacing reduces the contact constraint between the adapter plate and the shell wall, allowing the pressure relief valve to open faster under thermal runaway conditions, but the strength of the weld interface decreases simultaneously. Conversely, welding at locations with smaller spacing can improve the connection stability of the weld, but the excessive distance between the weld position and the shell wall weakens the pressure relief efficiency and reduces the pass rate of the needle penetration test.
[0005] It should be noted that the information disclosed in the above background section is only used to enhance the understanding of the background of this utility model and does not constitute any limitation on this utility model. Utility Model Content
[0006] In view of the shortcomings of the prior art described above, this utility model provides a secondary battery and battery pack. By reducing the distance between the welding area between the adapter plate and the housing flange in the battery and the side wall of the housing, the adapter plate can be opened quickly under thermal runaway conditions to achieve efficient pressure relief and air venting, while meeting the connection strength requirements of the welding area. This solves the problem of balancing mechanical performance and thermal safety performance between the welding position between the adapter plate and the housing and the distance between the housing wall and the mechanical performance.
[0007] This utility model provides a secondary battery, including a casing, a bare cell, an adapter plate, and a cover plate. The first end of the casing has an opening, and the inner side wall of the first end has a flange. The bare cell is housed in the casing. The adapter plate is located between the bare cell and the flange. The adapter plate includes a body and a rolled edge provided on the edge of the body. The body is electrically connected to the tab of the bare cell. The rolled edge is bent toward the side where the opening is located. The rolled edge is welded to the flange. The distance between the welding area between the rolled edge and the flange and the side wall of the casing is 0mm-2mm. The cover plate is connected to the first end of the casing and closes the opening.
[0008] In one embodiment of the present invention, the flange is an integral structure formed by rolling the side wall of the housing.
[0009] In one embodiment of this utility model, the distance between the welding area on the flange and the side wall of the housing is 1mm-1.5mm.
[0010] In one embodiment of the present invention, the rolled edge includes a first section and a second section, the first section is connected to the body, the second section is connected to the first section, and the welding area between the rolled edge and the flange is located in the second section.
[0011] In one embodiment of the present invention, the first section and the second section are bent toward the side of the body facing the cover plate so that the rolled edge has a triangular structure.
[0012] In one embodiment of the present invention, the end of the first section connecting to the second section is close to the flange, and the first section is inclined toward the side wall of the housing.
[0013] In one embodiment of the present invention, the angle between the end faces of the first section and the second section facing the body is not greater than 150°, the angle between the end faces of the first section and the body facing the second section is not greater than 90°, and the angle between the end face of the flange facing the bare cell and the side wall of the casing is not greater than 90°.
[0014] In one embodiment of this utility model, the second section is parallel to the body.
[0015] In one embodiment of this utility model, the height of the first section is 0mm-5mm.
[0016] In one embodiment of the present invention, a battery pack is also provided, including the aforementioned secondary battery.
[0017] The beneficial effects of this utility model are as follows: By reducing the distance between the welding area between the adapter piece and the housing flange in the battery and the side wall of the housing, and by limiting the included angle in the adapter piece structure and the included angle between the flange end face and the side wall of the housing, the adapter piece structure tends to be in a taut state in the battery. This allows it to open quickly under thermal runaway conditions to achieve efficient pressure relief and gas exhaust, avoiding further thermal runaway reactions, thereby improving the pass rate of the battery in the nail penetration test.
[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the present invention. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments conforming to the present invention and, together with the description, serve to explain the principles of the present invention. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:
[0020] Figure 1 This is a schematic diagram of the adapter plate structure in the first embodiment of the present invention;
[0021] Figure 2 This is a schematic diagram of the adapter plate structure in the second embodiment of the present invention;
[0022] Figure 3 This is a schematic diagram of the adapter plate structure in the third embodiment of the present invention;
[0023] Figure 4 This is a schematic diagram of the adapter plate structure in the fourth embodiment of the present invention.
[0024] In the diagram: 10, housing; 11, flange; 20, bare cell; 30, adapter piece; 31, body; 32, rolled edge; 321, first section; 322, second section; 323, first included angle; 324, second included angle; 325, third included angle; 40, welding area; 50, cover plate. Detailed Implementation
[0025] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. It should also be understood that the terminology used in the embodiments of this utility model is for describing specific implementation schemes and not for limiting the scope of protection of this utility model.
[0026] Please see Figures 1 to 4 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms used in this specification regarding position, quantity, etc., are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to these relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention's implementation.
[0027] Please see Figures 1 to 4 This utility model provides a secondary battery, including a housing 10, a bare cell 20, an adapter piece 30, and a cover plate 50. The first end of the housing 10 has an opening, and the inner side wall of the first end has a flange 11. The bare cell 20 is housed in the housing 10. The adapter piece 30 is located between the bare cell 20 and the flange 11. The adapter piece 30 includes a body 31 and a rolled edge 32 provided on the edge of the body 31. The body 31 is electrically connected to the tab of the bare cell 20. The rolled edge 32 is bent toward the side where the opening is located. The rolled edge 32 is welded to the flange 11. The distance between the welding area 40 between the rolled edge 32 and the flange 11 and the side wall of the housing 10 is 0mm-2mm. The cover plate 50 is connected to the first end of the housing 10 and closes the opening.
[0028] Specifically, in this embodiment of the invention, the distance between the welding area 40 and the side wall of the housing 10 is limited to 0mm-2mm to achieve a balance between the battery pressure relief and the connection strength between the adapter piece 30 and the housing 10. (See attached...) Figure 1As shown, before the flange 11 structure is formed, the assembly relationship between the housing 10 and the adapter piece 30 is as shown in the figure. The opening at the first end of the housing 10 can be processed to form an annular flange 11 structure. Its size design ensures the overall strength of the housing 10 and forms a conformal welding platform to connect the adapter piece 30. The body 31 of the adapter piece 30 can be stamped from a thin conductive material. The rolled edge 32 of the adapter piece 30 can be continuously bent with a specific arc to form an inclined bending feature that keeps it in a non-contact state with the inner wall of the housing 10, which avoids assembly interference and reserves space for thermal expansion.
[0029] It should be noted that the adapter plate 30 generally has corresponding hollowed-out portions for the flow of high-pressure gas during the decompression process of thermal runaway. However, the space of the hollowed-out portions cannot fully meet the high-speed decompression of the airflow during thermal runaway, which leads to the corresponding impact-bearing parts of the adapter plate 30 being broken and deflected. At this time, the distance between the welding area 40 of the adapter plate 30 and the flange 11 and the side wall of the housing 10 affects the breaking and deformation process of the adapter plate 30. Therefore, by controlling this distance, the opening efficiency of the adapter plate 30 during thermal runaway decompression can be optimized to meet the decompression requirements of the battery during thermal runaway. For the adapter plate 30 without hollowed-out portions, this setting of the distance between its welding area 40 and the side wall of the housing 10 is more crucial to the decompression effect, which will not be elaborated here.
[0030] Furthermore, in the welding area 40 between the adapter piece 30 and the flange 11, the welding connection can be achieved using a high-energy beam process to form a continuous and uniform weld bead within a specific range at the end of the rolled edge 32, ensuring the stability of the welding interface. The flange 11 is used to establish an axial positioning reference for the adapter piece 30, and the bending angle of the rolled edge 32 is used to control the radial contact pressure. Combined with the guidance of the inner wall of the housing 10, the circumferential alignment of the adapter piece 30 is achieved. In this way, the heat-affected zone of the weld is kept within a controllable range, forming a connection that meets mechanical strength requirements while avoiding thermal damage to the base material, and simultaneously satisfying the distance requirement for the welding area 40 to tend towards the side wall of the housing 10.
[0031] Furthermore, the rolled edge 32 of the adapter piece 30 connects to the flange 11, forming a cantilever structure of the body 31 of the adapter piece 30 relative to the rolled edge 32. Using the welding area 40 as a fulcrum, the structure of the adapter piece 30 creates a lever effect. When the internal pressure exceeds a threshold during battery thermal runaway, the force on the body 31 of the adapter piece 30 can cause it to deflect directionally and open, forming a pressure relief channel. A pressure buffer zone is formed between the rolled edge 32 and the side wall of the casing 10, affecting the speed at which the body 31 of the adapter piece 30 opens under pressure. Under the premise of satisfying the connection strength of the welding area 40, the smaller the distance, i.e., the shorter the stress arm length, the faster the body 31 of the adapter piece 30 opens. For example, in extreme conditions, to guide the orderly diffusion of heat flow and effectively reduce the local temperature rise rate, a structural weakening zone can be preset at the end of the rolled edge 32 to precisely control the opening and closing pressure threshold for pressure relief, thereby improving the pressure response performance of the adapter piece 30 structure.
[0032] In one embodiment, by reducing the distance between the welding area 40 of the negative electrode adapter 30 and the flange 11 in the cylindrical cell and the side wall of the housing 10 from 1.5 mm to 0.5 mm, the pass rate of the cell in the needle penetration test is increased from about 60% to 100%.
[0033] Thus, by optimizing the position of the welded area 40 between the rolled edge 32 of the adapter piece 30 and the side wall of the housing 10, a performance leap is achieved at the critical distance: Mechanically, the deformation strengthening mechanism of the bending structure multiplies the shear strength of the weld; thermally, the critical layout causes an order-of-magnitude acceleration in the pressure relief response, resulting in a qualitative leap in needle penetration protection performance. Adaptive compensation technology is employed during assembly to effectively absorb component forming tolerances, ensuring high repeatability of the welding area and providing a reliable guarantee for mass production.
[0034] Please see Figures 1 to 4 In one embodiment, the flange 11 is an integral structure with the housing 10 formed by rolling the sidewall of the housing 10.
[0035] Specifically, in this embodiment of the invention, an integral construction process is adopted to form a plastic annular flange 11 on the sidewall of the shell 10 through a roll forming process, thereby achieving a seamless transition between the flange 11 and the shell 10 substrate. While maintaining the continuity of the shell 10, a gradually changing edge protrusion structure is formed through material flow control. This eliminates the assembly interface of traditional split structures and constructs a continuous force transmission path through the self-supporting properties of the material. Furthermore, a gradually changing curvature transition design can be adopted at the root of the roll-formed flange 11, so that the stress field achieves a gentle gradient distribution along the generatrix of the shell 10, avoiding stress concentration caused by abrupt cross-section changes. At the same time, the mating plane at the top of the flange 11 forms a full circumferential surface contact with the rolled edge 32 of the transition piece 30, and the contact pressure distribution is uniform. This seamless transition method enables the shell 10 and the transition piece 30 structure to exhibit vibration damping characteristics like an integral component under dynamic loads, further ensuring its structural stability.
[0036] Please see Figures 2 to 4 In one embodiment, the distance between the welding area 40 on the flange 11 and the sidewall of the housing 10 is 1mm-1.5mm.
[0037] Specifically, in this embodiment of the invention, the distance between the welding area 40 of the adapter piece 30 and the flange 11 and the sidewall of the housing 10 is further limited to 1mm-1.5mm, and the spacing is controlled within the micrometer-level fluctuation range using corresponding precision forming technology. The gap distance is optimized through size matching, with 1mm set as the lower limit to meet the stress release requirements of the welding heat-affected zone, providing deformation compensation space for the heterogeneous expansion of the base material and the solder under thermal cycling conditions. The upper limit of 1.5mm is determined based on the penetration threshold of the plasma arc during welding, ensuring stability during welding. This set gap distance range reduces the peak value of welding residual stress, improves the opening response speed of the pressure relief channel, and allows for real-time compensation of forming errors through distance measurement feedback during manufacturing, relying on linkage positioning, ensuring the process stability of the spacing parameters.
[0038] Please see Figures 2 to 4 In one embodiment, the rolled edge 32 includes a first section 321 and a second section 322. The first section 321 is connected to the body 31, and the second section 322 is connected to the first section 321. The welding area 40 between the rolled edge 32 and the flange 11 is located in the second section 322.
[0039] Specifically, in this embodiment of the invention, the rolled edge 32 structure of the adapter piece 30 adopts a partitioned design, achieving different functions through the morphological differentiation of the first section 321 and the second section 322. The first section 321 serves as a deformation buffer, utilizing a set bending angle and the elasticity of the rolled edge 32 itself to form a spring-like structure with strain energy storage characteristics. On one hand, it can absorb the vibration energy between the bare cell 20 and the casing 10 during battery use; on the other hand, it can act as a buffer for the structural deformation of the adapter piece 30, preventing it from opening due to pressure changes that do not reach a threshold. The second section 322 serves as the interface of the welding area 40, used to match the contour of the flange 11 portion, ensuring the connection strength of the weld. Simultaneously, the end of the second section 322, i.e., the end of the rolled edge 32, can extend away from the surface of the flange 11 and towards the body 31 portion of the adapter piece 30. In this way, when the adapter plate 30 is depressurized and opened, it can provide a new fulcrum for deflection deformation, preventing the adapter plate 30 from being in the same position in the bending area of deflection deformation, which would lead to excessive bending and breakage. On the other hand, it can prevent the deflection deformation of the adapter plate 30 from accumulating in the local space formed by the flange 11, and keep the adapter plate 30 from generating deflection deformation smoothly.
[0040] Thus, by adopting a partitioned structure, under normal operating conditions, the elastic properties of the first section 321 can absorb the main mechanical vibration energy, reducing the alternating stress transmitted to the welding area 40 to below the material fatigue threshold, ensuring the stability of the welded connection for long-term use. Under extreme operating conditions, i.e., thermal runaway conditions, the structure of the second section 322 can guide the deflection deformation tendency of the adapter plate 30 body 31, keeping the adapter plate 30 in a controllable state during the pressure relief and opening process.
[0041] Please see Figure 2 and Figure 3 In one embodiment, the first segment 321 and the second segment 322 are bent toward the side of the body 31 toward the cover plate 50 so that the rolled edge 32 has a triangular structure.
[0042] Specifically, in this embodiment of the invention, the triangular structure formed by the first segment 321 and the second segment 322, under normal conditions, constitutes a stress arch shell with the arched segment of the body 31 of the adapter plate 30 and the triangular segment of the rolled edge 32 of the adapter plate 30. This uniformly transforms the pressure on the body 31 of the adapter plate 30 from the bare battery cell 20 side into circumferential tensile stress on the rolled edge 32 of the adapter plate 30, ensuring the geometric stability of the triangular structure. Under the critical pressure of thermal runaway depressurization, during the initial crack propagation stage, the additional bending moment generated at the two waists, namely the first segment 321 and the edge of the body 31, causes the crack propagation rate to decrease, ensuring the gradual expansion of the opening area of the pressure relief port. When the opening reaches the critical value, i.e., when the adapter plate 30 breaks, the arch of the first segment 321 undergoes elastic deformation, releasing stored energy and changing the depressurization speed of the adapter plate 30. This optimizes the emission of high-temperature gas during the depressurization process and simultaneously controls the amplitude of pressure oscillation within the material's tolerance threshold.
[0043] Please see Figure 2 and Figure 3 In one embodiment, the end of the first segment 321 that connects to the second segment 322 is close to the flange 11, and the first segment 321 is inclined toward the side wall of the housing 10.
[0044] Specifically, in this embodiment of the invention, the first section 321 extends towards the side wall of the housing 10 with a specific inclined posture, that is, the two ends of the first section 321 are close to the flange 11 and the side wall of the housing 10 respectively, forming an inclined structure. This causes the stress flow lines to be deflected: part of the axial load of the body 31 is converted into circumferential compressive stress of the housing 10 on the first section 321 through the inclined surface, thereby reducing the stress value directly received by the welding interface. The inclination angle of the first section 321 forms a dynamic interference relationship with the wall surface of the housing 10, maintaining a non-contact state under normal conditions, thereby forming a pressure buffer zone. When the interior is in a thermal runaway overpressure state, the inclined section generates a lever effect under the force of the body 31, causing the fracture of the adapter piece 30 to occur in the compressive stress concentration area in the middle of the body 31 or in a pre-set structural weakening area. Such directional fracture can accelerate the opening speed of the pressure relief channel.
[0045] Please see Figure 2 and Figure 3 In one embodiment, the angle of the first included angle 323 formed between the end faces of the first section 321 and the second section 322 facing the body 31 is not greater than 150°, the angle of the second included angle 324 formed between the end faces of the first section 321 and the body 31 facing the second section 322 is not greater than 90°, and the angle of the third included angle 325 formed between the end face of the flange 11 facing the bare cell 20 and the side wall of the housing 10 is not greater than 90°.
[0046] Specifically, in this embodiment of the invention, the first included angle 323 forms an open obtuse or acute angle configuration on the side of the rolled edge 32 facing the body 31 between the first segment 321 and the second segment 322. This allows the connection point corresponding to the first included angle 323 to be subjected to bidirectional tensile stress, converting the expansion energy of the bare cell 20 into elastic deformation energy during charge-discharge cycles. Simultaneously, under normal conditions, the first segment 321 and the second segment 322 form a truss-like support structure with the body 31, thereby improving the axial stiffness of the rolled edge 32 in the housing 10. During thermal runaway and pressure relief, the obtuse or acute angle apex at the connection point of the first segment 321 and the second segment 322 preferentially undergoes plastic hinge deformation, guiding the deflection deformation path in the adapter piece 30 to occur along a preset direction. The second included angle 324 between the first section 321 and the body 31 is defined as an acute angle, and the first included angle 323 between the first section 321 and the second section 322 is defined as an obtuse or acute angle configuration, so that the first section 321, the second section 322 and the body 31 of the rolled edge 32 are conducive to forming a triangular structure. This makes the bent part of the rolled edge 32 taut, and the pressure relief pressure borne by the adapter piece 30 is fully applied to itself and causes it to break open, thereby allowing the adapter piece 30 to open quickly under thermal runaway pressure relief.
[0047] Furthermore, the third included angle 325 is between the end faces of the flange 11 and the side wall of the housing 10. As the angle approaches 0°, the welding area 40 also approaches the side wall of the housing 10 along with the surface of the flange 11. Thus, without changing the position of the welding area 40 before the grooving process, the distance between the welding area 40 and the side wall of the housing 10 is reduced, thereby improving the opening efficiency of the adapter piece 30 under thermal runaway.
[0048] Thus, by limiting the angle range of the included angle between the rolled edge 32 and the flange 11 of the adapter piece 30, the opening speed of the adapter piece 30 under depressurization state is increased, thereby improving the pass rate of the battery in the nail penetration test.
[0049] Please see Figure 4 In one embodiment, the second segment 322 is parallel to the body 31.
[0050] Specifically, in this embodiment of the invention, a flat adapter plate 30 with soldered pins is also present. The second section 322 of the adapter plate 30 is approximately parallel to the body 31. In this structural configuration, the first angle 323 and the second angle 324 between the body 31 of the adapter plate 30, the first section 321 of the rolled edge 32, and the second section 322 are approximately 90°. At the same time, the third angle 325 between the end face of the flange 11 and the side wall of the housing 10 is also approximately 90°. Thus, in the thermal runaway pressure relief state, the deformation process of the adapter plate 30 is as follows: the body 31 first undergoes deflection deformation, which then drives the first section 321 of the rolled edge 32 to deflect relative to the second section 322. After the first section 321 is deflected by the body 31 to abut against the second section 322, the deformation margin of the rolled edge 32 is exhausted, and the pressure relief pressure borne by the adapter plate 30 is completely applied to itself, causing it to break open and opening the pressure relief channel of the adapter plate 30.
[0051] Please see Figure 4 In one embodiment, the height of the first segment 321 is 0mm-5mm.
[0052] Furthermore, in this embodiment of the present invention, by limiting the length of the first section 321, i.e. the height in the flat welding pin, when the size of the first section 321 is closer to 0mm, the deformation of the first section 321 relative to the second section 322 caused by the body 31 in the thermal runaway pressure relief state is smaller, thereby making the deformation allowance of the rolled edge 32 part exhausted more quickly, so that the adapter piece 30 is in a taut state, so that the pressure relief pressure borne by the adapter piece 30 is fully applied to itself and breaks, thereby opening the pressure relief channel of the adapter piece 30.
[0053] In other words, in the flat solder pin structure, the body 31, the first section 321 and the second section 322 of the adapter 30 form an approximately rectangular structure. When the size of the first section 321 is closer to 0, that is, the height of the rectangular structure is closer to 0, the second section 322 in the rolled edge 32 of the adapter 30 approaches the body 31 of the adapter 30, thereby putting the adapter 30 in a taut state. Oil inlet is beneficial for the battery to open quickly under the nail penetration test conditions to release pressure and vent air, avoiding the aggravation of thermal runaway.
[0054] This utility model also provides a battery pack, including the aforementioned secondary battery.
[0055] Specifically, in this embodiment of the present invention, by integrating the above-mentioned secondary battery structure, the size of the welding area 40 between the flange 11 in the battery housing 10 and the negative electrode adapter 30 and the side wall of the housing 10 is controlled within a certain range, and the distance is reduced. As a result, under the thermal runaway condition corresponding to the nail penetration test of the battery, the opening speed of the adapter 30 structure under the impact of hot air pressure is improved, thereby quickly releasing pressure and venting gas to avoid the aggravation of battery thermal runaway, controlling the internal temperature and pressure of the battery, delaying the thermal runaway chain reaction of adjacent batteries, thereby improving the pass rate of the nail penetration test and the safety during thermal runaway.
[0056] In summary, the secondary battery and battery pack provided by this utility model reduce the distance between the welding area between the adapter piece and the flange of the casing and the side wall of the casing. This is achieved by limiting the included angle between the body of the adapter piece and the rolled edge of the adapter piece, as well as the included angle between the flange end face and the side wall of the casing. While meeting the connection strength requirements of the welding area between the adapter piece and the flange, the adapter piece structure tends to be in a taut state within the battery. This reduces the deformation allowance of the adapter piece structure during pressure relief, preventing it from breaking apart. Consequently, under thermal runaway conditions, the adapter piece can quickly open to achieve efficient pressure relief and venting, avoiding further thermal runaway reactions and thus improving the battery's pass rate in nail penetration tests.
[0057] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.
Claims
1. A secondary battery characterized by comprising: The application relates to a secondary battery, which comprises the following parts: a shell (10), the first end of the shell (10) being provided with an opening, the inner side of the side wall of the first end of the shell (10) being provided with a flange (11); a bare electric core (20) accommodated in the shell (10); an adapter sheet (30) located between the bare electric core (20) and the flange (11), the adapter sheet (30) comprising a body (31) and a curled edge (32) arranged at the edge of the body (31), the body (31) being electrically connected with the tab of the bare electric core (20), the curled edge (32) being bent towards the side where the opening is located, the curled edge (32) being welded with the flange (11), and the distance between the welding area (40) between the curled edge (32) and the flange (11) and the side wall of the shell (10) being 0mm-2mm; and a cover plate (50) connected with the first end of the shell (10) and closing the opening.
2. The secondary battery according to claim 1, characterized by The flange (11) is an integral structure of the shell (10) formed by rolling the side wall of the shell (10).
3. The secondary battery according to claim 1, characterized by The distance between the welding area (40) on the flange (11) and the side wall of the shell (10) is 1mm-1.5mm.
4. The secondary battery according to claim 1, characterized by The curled edge (32) comprises a first section (321) and a second section (322), the first section (321) being connected with the body (31), the second section (322) being connected with the first section (321), and the welding area (40) between the curled edge (32) and the flange (11) being located at the second section (322).
5. The secondary battery according to claim 4, characterized by The first section (321) and the second section (322) are bent towards the side of the body (31) facing the cover plate (50), so that the curled edge (32) is in a triangular structure.
6. The secondary battery according to claim 5, characterized by The end of the first section (321) connecting the second section (322) is close to the flange (11), and the first section (321) is inclined towards the side wall of the shell (10).
7. The secondary battery according to claim 4, characterized by The angle of the first included angle (323) between the end faces of the first section (321) and the second section (322) towards the side of the body (31) is not greater than 150 degrees, the angle of the second included angle (324) between the end face of the first section (321) and the body (31) towards the side of the second section (322) is not greater than 90 degrees, and the angle of the third included angle (325) between the end face of the flange (11) towards the side of the bare electric core (20) and the side wall of the shell (10) is not greater than 90 degrees.
8. The secondary battery according to claim 4, characterized by The second section (322) is parallel to the body (31).
9. The secondary battery according to claim 8, characterized by The height of the first section (321) is 0mm-5mm.
10. A battery pack, characterized by, The application further relates to a secondary battery comprising any one of the secondary batteries according to claims 1-9.