Battery cells, battery packs and electrical devices

Abstract

A battery cell, a battery assembly, and an electrical device are provided. The battery cell includes a housing, an electrode assembly, and a pressure relief mechanism. The housing has a wall, the electrode assembly is housed within the housing, and the pressure relief mechanism is disposed in the wall. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion and a raised portion. The weak portion is configured to at least partially break down to release pressure when the pressure inside the housing reaches a threshold. The raised portion is located within the area enclosed by the weak portion and is a raised structure that bulges outward from the electrode assembly. The raised portion is provided with a reinforcing portion. By providing a reinforcing portion on the raised portion, the raised portion is strengthened, thus preventing collapse. This allows for timely pressure relief when the pressure inside the battery cell reaches the threshold, improving the reliability of the battery cell. Furthermore, it improves the structural consistency of the raised portions of multiple battery cells, thereby enhancing the consistency of the detonation pressure of multiple battery cells.

Description

Technical Field

[0001] This application relates to the field of batteries, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must also be considered. However, the reliability of current batteries is relatively poor. Utility Model Content

[0003] The purpose of this application is to provide a battery cell, a battery device, and an electrical device, which aims to improve the problem of poor battery reliability in related technologies.

[0004] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a housing, an electrode assembly, and a pressure relief mechanism. The housing has a wall portion, the electrode assembly is housed within the housing, the pressure relief mechanism is disposed on the wall portion, the base material of the pressure relief mechanism is iron, the pressure relief mechanism includes a weak portion and a raised portion, the weak portion is configured to be at least partially destroyed to release the pressure when the pressure inside the housing reaches a threshold, the raised portion is located in the area enclosed by the weak portion, the raised portion is a raised structure that bulges along a direction close to or away from the electrode assembly, and the raised portion is provided with a reinforcing portion.

[0005] In the aforementioned technical solutions, existing pressure relief mechanisms, during pressure relief, gradually bulge from a flat structure away from the electrode assembly under the internal pressure of the battery cell. After bulging, they open to release pressure under the internal pressure of the battery cell. In this embodiment, however, the bulge of the pressure relief mechanism bulges away from the electrode assembly, and the bulge forms a pre-deformation on the inner side of the weak part, facilitating pressure relief by cracking the weak part. Thus, under the same burst pressure, the thickness of the weak part can be greater. During normal use of the battery cell, the weak part is less likely to crack prematurely due to internal pressure changes or external impacts, reducing the risk of premature damage and improving the battery cell's lifespan. The pressure relief mechanism's base material is iron, which effectively improves the structural strength of the weak part, reduces the risk of cracking under external forces, and further improves the battery cell's lifespan and reliability. By providing reinforcing portions on the raised portions, the raised portions are strengthened, making them less prone to collapse. This allows the weak points to crack and release pressure promptly when the internal pressure of the battery cell reaches a threshold, improving the reliability of the battery cell. Furthermore, it improves the structural consistency of the raised portions across multiple battery cells, thus enhancing the consistency of their burst pressure. Compared to existing aluminum explosion-proof valves, the weak point thickness of the pressure relief mechanism provided in this embodiment is smaller. During manufacturing, even a slight change in the thickness of the weak point can significantly alter the burst pressure of the battery cell. By making the raised portions bulge away from the electrode assembly, the thickness of the weak point can be increased under the same burst pressure. A thicker weak point is easier to manufacture, thus improving the consistency of burst pressure across multiple battery cells. Additionally, when the weak point thickness is small, the pressure relief mechanism is also thinner to facilitate processing and reduce material costs. This increases the risk of the raised portions collapsing, thus necessitating the addition of reinforcing portions to strengthen the raised portions and reduce the risk of collapse.

[0006] As an optional technical solution in this application embodiment, the hardness of the reinforcing part is greater than the hardness of the area of ​​the raised part where the reinforcing part is not provided.

[0007] In the above technical solution, by making the hardness of the reinforcing part greater than the hardness of the area of ​​the raised part where no reinforcing part is provided, the strength of the reinforcing part can be improved accordingly, thereby enhancing the reinforcing effect of the reinforcing part on the raised part and making the raised part less prone to collapse.

[0008] As an optional technical solution in this application embodiment, the raised portion includes an arc-shaped area, the length direction of the arc-shaped area is a first direction, any two cross sections of the arc-shaped area perpendicular to the first direction are the same first arc shape, and the first direction is perpendicular to the thickness direction of the wall portion; the reinforcing portion is at least partially disposed in the arc-shaped area.

[0009] In the above technical solution, the arc-shaped area of ​​the raised portion is more prone to collapse. By placing the reinforcing portion at least partially in the arc-shaped area, the risk of collapse is reduced, making the arc-shaped area less prone to abnormal deformation. On the one hand, this allows the weak part to crack and release pressure in time when the internal pressure of the battery cell reaches the threshold, which is beneficial to improving the reliability of the battery cell. On the other hand, it makes the structure of the raised portions of multiple battery cells more consistent, thereby improving the consistency of the explosion pressure of multiple battery cells.

[0010] As an optional technical solution in this application embodiment, the raised portion further includes a transition zone, the transition zone connecting the arc-shaped region and the weak portion, the cross section of the transition zone parallel to the first direction is a second arc shape, along the thickness direction of the wall portion, there is a height difference between the end of the second arc shape near the weak portion and the end of the second arc shape near the arc-shaped region, and the transition zone is provided at both ends of the arc-shaped region along the first direction.

[0011] In the above technical solution, the transition zone can connect the arc-shaped area and the weak part, so that the arc-shaped area can naturally transition to the weak part, which helps to reduce the risk of stress concentration in the pressure relief mechanism.

[0012] As an optional technical solution in this application embodiment, the weak portion includes a first weak segment, a second weak segment, and a third weak segment. The first weak segment and the third weak segment are arranged opposite to each other along the first direction. The second weak segment connects the first weak segment and the third weak segment. The first weak segment and the third weak segment are arc-shaped, and the second weak segment is straight. One end of the arc-shaped area along the second direction is connected to the second weak segment. One transition area is connected to the first weak segment, and the other transition area is connected to the third weak segment. The first direction, the second direction, and the thickness direction of the wall are perpendicular to each other.

[0013] In the above technical solution, one transition zone connects the first weak segment and one end of the arc-shaped zone to achieve a transition from one end of the arc-shaped zone to the first weak segment, and another transition zone connects the third weak segment and the other end of the arc-shaped zone to achieve a transition from the other end of the arc-shaped zone to the third weak segment. This helps to reduce the risk of stress concentration in the pressure relief mechanism. One end of the arc-shaped zone along the second direction is connected to the second weak segment, which facilitates the bulge pulling on the weak segment when the battery cell is depressurized, thus facilitating the opening of the weak segment for pressure relief.

[0014] As an optional technical solution in this application embodiment, the weak part includes a fourth weak segment, the fourth weak segment is straight, and the first weak segment, the second weak segment, the third weak segment and the fourth weak segment are connected end to end; along the second direction, the end of the arc-shaped area away from the second weak segment is connected to the fourth weak segment.

[0015] In the above technical solution, the first, second, third, and fourth weak segments are connected end-to-end. When a battery cell is depressurized, it can crack along at least one of the first, second, third, and fourth weak segments, thereby opening a larger opening and achieving rapid depressurization. Along the second direction, an arc-shaped region connects the second and fourth weak segments, facilitating the arc-shaped region to pull on the second and fourth weak segments, thus facilitating the opening of the second and fourth weak segments for depressurization.

[0016] As an optional technical solution in this application embodiment, the orthographic projection of the reinforcing part is arc-shaped in the projection plane perpendicular to the thickness direction of the wall.

[0017] In the above technical solution, by making the orthographic projection of the reinforcing part in the projection plane perpendicular to the thickness direction of the wall part into an arc shape, the reinforcing part has a better strengthening effect, good structural stability, and is conducive to reducing stress concentration.

[0018] As an optional technical solution in this application embodiment, the raised portion is provided with a plurality of the reinforcing portions, the plurality of reinforcing portions including a first reinforcing portion and a second reinforcing portion, and in a projection plane perpendicular to the thickness direction of the wall portion, the openings of the orthogonal projections of the first reinforcing portion and the openings of the orthogonal projections of the second reinforcing portion are arranged back to back.

[0019] In the above technical solution, multiple reinforcing parts are provided on the raised portion to enhance the reinforcement effect. The orthographic projections of both the first and second reinforcing parts in a plane perpendicular to the thickness direction of the wall are arc-shaped. Furthermore, the openings of the orthographic projections of the first and second reinforcing parts in the same plane are arranged back-to-back. This increases the radiation range of the first and second reinforcing parts, expanding the reinforcement range of the raised portion and making it less prone to collapse. On one hand, this allows the weak points to crack and release pressure promptly when the internal pressure of the battery cell reaches a threshold, improving the reliability of the battery cell. On the other hand, it improves the structural consistency of the raised portions of multiple manufactured battery cells, thereby enhancing the consistency of the detonation pressure of the multiple battery cells.

[0020] As an optional technical solution in this application embodiment, the raised portion includes an arc-shaped area, the arc-shaped area extends along a first direction, the arc-shaped area is arc-shaped along a cross section perpendicular to the first direction, and the reinforcing portion is disposed in the arc-shaped area; in the projection plane perpendicular to the thickness direction of the wall portion, the opening of the orthographic projection of the first reinforcing portion and the opening of the orthographic projection of the second reinforcing portion are disposed opposite to each other along a second direction, and the first direction, the second direction and the thickness direction of the wall portion are perpendicular to each other.

[0021] In the above technical solution, the arc-shaped area of ​​the raised portion is more prone to collapse. By having the reinforcing portion at least partially disposed in the arc-shaped area, the risk of collapse in the arc-shaped area is reduced, making the arc-shaped area less prone to abnormal deformation. In the projection plane perpendicular to the thickness direction of the wall portion, the openings of the orthographic projections of the first reinforcing portion and the second reinforcing portion are arranged opposite to each other along the second direction to further enhance the radiation range of the first and second reinforcing portions, increase the reinforcement range of the arc-shaped area, make the arc-shaped area less prone to collapse, and improve the structural consistency of the raised portions of the manufactured multiple battery cells, thereby helping to improve the consistency of the detonation pressure of the multiple battery cells.

[0022] As an optional technical solution in this application embodiment, the first reinforcing part is connected to the second reinforcing part.

[0023] In the above technical solution, by connecting the first reinforcing part to the second reinforcing part, the reinforcing effect on the arc-shaped area is further improved.

[0024] As an optional technical solution in this application embodiment, the first reinforcing part and the second reinforcing part are connected to form a converging area, the converging area passes through the mid-section of the arc-shaped area, and the mid-section is perpendicular to the second direction.

[0025] In the above technical solution, the collection area passes through the mid-section of the arc-shaped area. A part of the first reinforcing part is located on one side of the mid-section, and a part of the second reinforcing part is located on the other side of the mid-section. This can effectively strengthen the parts of the arc-shaped area located on both sides of the mid-section, resulting in better structural stability of the pressure relief mechanism.

[0026] As an optional technical solution in this application embodiment, the orthographic projections of the first reinforcing part and the second reinforcing part are spaced apart in a projection plane perpendicular to the thickness direction of the wall.

[0027] In the above technical solution, the orthographic projection of the first reinforcing part in the projection plane perpendicular to the thickness direction of the wall and the orthographic projection of the second reinforcing part in the projection plane perpendicular to the thickness direction of the wall are set alternately to increase the radiation range of the first and second reinforcing parts, increase the reinforcement range of the arc-shaped area, make the arc-shaped area less prone to collapse, and make the structural consistency of the raised parts of the manufactured multiple battery cells better, thereby helping to improve the consistency of the detonation pressure of the multiple battery cells.

[0028] As an optional technical solution in this application embodiment, in a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the first reinforcing portion and the orthographic projection of the second reinforcing portion are respectively located on both sides of the mid-section of the arc-shaped region, and the mid-section is perpendicular to the second direction.

[0029] In the above technical solution, the first reinforcing part and the second reinforcing part are located on both sides of the middle section, so that the arc-shaped area located on both sides of the middle section can play a good reinforcing effect, which makes the pressure relief mechanism have better structural stability.

[0030] As an optional technical solution in this application embodiment, along the first direction, the length of the arc-shaped area is L1, the length of the reinforcing part is L2, L2 / L1≥0.6, and the first direction is perpendicular to the thickness direction of the wall part.

[0031] In the above technical solution, when L2 / L1≥0.6, the length of the reinforcing part along the first direction is larger and the radiation range of the reinforcing part is larger, which is conducive to increasing the reinforcement range of the arc-shaped area, making the arc-shaped area less prone to collapse, and making the structural consistency of the raised parts of the multiple battery cells better, thereby helping to improve the consistency of the explosion pressure of the multiple battery cells.

[0032] As an optional technical solution in this application embodiment, along the first direction, the arc-shaped region is provided with a plurality of reinforcing parts arranged at intervals, the length of the arc-shaped region is L1, the sum of the lengths of the plurality of reinforcing parts is L3, L3 / L1≥0.6, and the first direction is perpendicular to the thickness direction of the wall portion.

[0033] In the above technical solution, when L3 / L1≥0.6, the total length of the multiple reinforcing parts along the first direction is large, and the multiple reinforcing parts work together to strengthen the arc-shaped area, and the strengthening range of the arc-shaped area is large, making the arc-shaped area less prone to collapse, and making the structure of the raised parts of the multiple battery cells more consistent, which is conducive to improving the consistency of the explosion pressure of the multiple battery cells.

[0034] As an optional technical solution in this application embodiment, along the first direction, the arc-shaped area is provided with a plurality of first reinforcing parts arranged at intervals, and the second reinforcing parts are provided in a one-to-one correspondence with the first reinforcing parts.

[0035] In the above technical solution, by setting multiple first reinforcing parts and multiple second reinforcing parts, with the first reinforcing parts and the second reinforcing parts being set in a one-to-one correspondence, the reinforcement effect on the arc-shaped area is further improved, and the risk of the arc-shaped area collapsing is reduced.

[0036] As an optional technical solution in this application embodiment, the raised portion has a first surface facing or away from the electrode assembly, and the reinforcing portion protrudes from the first surface.

[0037] In the above technical solution, the reinforcing part can be a protrusion extending from the first surface. The reinforcing part strengthens the raised part, improving its resistance to deformation and making it less prone to collapse. On the one hand, this allows the weak part to crack and release pressure in time when the internal pressure of the battery cell reaches the threshold, which is beneficial to improving the reliability of the battery cell. On the other hand, it makes the structure of the raised parts of multiple battery cells more consistent, thereby improving the consistency of the explosion pressure of multiple battery cells.

[0038] As an optional technical solution in this application embodiment, the raised portion has a second surface opposite to the first surface, the raised portion is provided with a first groove, the first groove is recessed from the second surface in a direction close to the first surface, and the reinforcing portion protruding from the first surface is formed at the position of the raised portion corresponding to the first groove.

[0039] In the above technical solution, during molding, a first groove can be formed on the second surface by stamping, thereby forming a reinforcing part protruding from the first surface. The molding method of the reinforcing part is simple. The setting of the first groove makes the raised part form a recessed structure at the location where the reinforcing part is set, so that the reinforcing part has better resistance to deformation and improves the reinforcing effect of the reinforcing part on the raised part.

[0040] As an optional technical solution in this application embodiment, the first surface is the surface of the raised portion facing the electrode assembly, and the second surface is the surface of the raised portion away from the electrode assembly.

[0041] In the above technical solution, when the first surface is the surface where the raised portion faces the electrode assembly and the second surface is the surface where the raised portion faces away from the electrode assembly, the first groove is recessed in the direction facing the electrode assembly, and the raised portion is raised in the direction away from the electrode assembly. The recessed direction of the first groove is opposite to the raised direction of the raised portion, which is beneficial to optimize the force distribution.

[0042] As an optional technical solution in this application embodiment, the raised portion has a second surface facing or away from the electrode assembly, the second surface is formed with a first groove, the raised portion includes a body portion and a thinning portion located at the bottom of the first groove, the thinning portion is connected to the body portion, the thickness of the thinning portion is less than the thickness of the body portion, the hardness of the thinning portion is greater than the hardness of the body portion, and the thinning portion forms the reinforcing portion.

[0043] In the above technical solution, the first groove can be formed by stamping, so that the bottom wall of the first groove forms the aforementioned thinned part. In this way, the bottom wall of the first groove will undergo cold work hardening (the grain arrangement changes, resulting in lattice distortion, which reduces the plasticity of the metal and increases the hardness of the material), thereby increasing the hardness of the thinned part and correspondingly increasing the strength of the thinned part, thus achieving the reinforcement of the raised part.

[0044] As an optional technical solution in this application embodiment, the pressure relief mechanism is provided with a second groove, the bottom wall of the second groove includes the weak part, and the first groove and the second groove are provided on the same side of the pressure relief mechanism.

[0045] In the above technical solution, a weak part is formed on the pressure relief mechanism by creating a pressure relief groove. When the battery cell is depressurized, the pressure relief mechanism splits along at least a portion of the weak part. This method is simple, convenient, and low-cost. By setting the first groove and the second groove on the same side of the pressure relief mechanism, it is convenient to process the first groove and the second groove simultaneously, which helps to improve production efficiency and optimize the stress on the pressure relief mechanism.

[0046] As an optional technical solution in this application embodiment, the pressure relief mechanism further includes a connecting portion, which surrounds the outside of the weak portion. The connecting portion is integrally formed with the wall portion or is separately provided and connected. The connecting portion at least partially protrudes in the direction close to the electrode assembly, and the weak portion is connected to the part of the connecting portion closest to the electrode assembly.

[0047] In the above technical solution, the connecting portion at least partially protrudes along the direction close to the electrode assembly, while the raised portion protrudes along the direction away from the electrode assembly. The protrusion direction of the connecting portion is opposite to that of the raised portion, allowing the raised portion to utilize the height of the connecting portion for its own protrusion. This helps to reduce the height of the raised portion beyond the surface of the connecting portion furthest from the electrode assembly, reducing the space occupied by the battery cell or battery device and improving the energy density of the battery cell or battery device. Furthermore, since the weak portion is connected to the part of the connecting portion closest to the electrode assembly—that is, the weak portion is closer to the electrode assembly than the connection point between the connecting portion and the wall—one end of the connecting portion is constrained by the wall. Under air pressure, the raised portion of the connecting portion along the direction close to the electrode assembly compresses the weak portion, thereby suppressing cracking of the weak portion and preventing creep failure of the weak portion during normal operation of the battery cell, effectively extending the life of the battery cell.

[0048] As an optional technical solution in this application embodiment, the thickness of the raised portion is H, which satisfies: 0.05mm≤H≤0.3mm.

[0049] In the above technical solutions, when H ≤ 0.3 mm, the thickness of the raised portion is relatively thin, which helps to reduce the space occupied by the raised portion on the internal space of the battery cell or battery device, thereby improving the energy density of the battery cell. Additionally, when the thickness of the raised portion is thin, it is relatively more prone to collapse, thus requiring reinforcement to strengthen it and reduce the risk of collapse. When H ≥ 0.05 mm, the thickness of the raised portion is not too small, and its strength is not too low, making it less susceptible to damage under external forces, which helps to improve the lifespan and reliability of the battery cell. Therefore, when 0.05 mm ≤ H ≤ 0.3 mm, it is beneficial to improve the energy density, lifespan, and reliability of the battery cell.

[0050] As an optional technical solution in this application embodiment, 0.075mm≤H≤0.25mm.

[0051] In the above technical solutions, when H ≤ 0.25 mm, the thickness of the raised portion is thinner, which is more conducive to reducing the space occupied by the raised portion in the internal space of the battery cell or battery device, thereby improving the energy density of the battery cell. However, when the raised portion is thinner, it is more prone to collapse, thus requiring reinforcement to strengthen it and reduce the risk of collapse. When H ≥ 0.075 mm, the thickness of the raised portion is not too small, and its strength is not too low, making it less susceptible to damage under external forces, which is beneficial to improving the lifespan and reliability of the battery cell. Therefore, when 0.075 mm ≤ H ≤ 0.25 mm, it is beneficial to improve the energy density, lifespan, and reliability of the battery cell.

[0052] As an optional technical solution in this application embodiment, the material of the pressure relief mechanism includes at least one of stainless steel and carbon steel.

[0053] In the above technical solutions, stainless steel and carbon steel have high strength, which can effectively improve the structural strength of weak parts, reduce the risk of cracking of weak parts under external force, reduce the risk of premature damage to weak parts, and improve the service life and reliability of battery cells.

[0054] As an optional technical solution in this application embodiment, the material of the pressure relief mechanism includes at least one of SUS304 stainless steel, SUS305 stainless steel or SUS316L stainless steel.

[0055] In the above technical solutions, 304 stainless steel, 305 stainless steel and 316 stainless steel have advantages such as corrosion resistance, high temperature resistance and good processing performance. The pressure relief mechanism made of 304 stainless steel, 305 stainless steel or 316 stainless steel has high strength, which can effectively improve the structural strength of weak parts, reduce the risk of cracking of weak parts under external force, reduce the risk of premature damage to weak parts, improve the service life and reliability of battery cells, and improve the consistency of burst pressure of multiple battery cells.

[0056] As an optional technical solution in this application embodiment, the pressure relief mechanism is separately disposed from the wall portion, the wall portion is provided with a pressure relief hole, and the pressure relief mechanism is installed on the wall portion and covers the pressure relief hole.

[0057] In the above technical solution, the pressure relief mechanism and the wall part are separately set and installed on the wall part to facilitate processing and manufacturing.

[0058] As an optional technical solution in this application embodiment, both the pressure relief mechanism and the base material of the wall are iron, and the pressure relief mechanism is welded to the wall.

[0059] In the above technical solution, the base material of both the pressure relief mechanism and the wall is iron, which makes it easier to weld the pressure relief mechanism and the wall. This helps to reduce the phenomenon of welding cracks between the pressure relief mechanism and the wall, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0060] As an optional technical solution in this application embodiment, the pressure relief mechanism is integrally formed with the wall portion.

[0061] In the above technical solution, the pressure relief mechanism is integrally formed with the wall, eliminating the need for additional welding or bonding processes, which helps reduce the risk of leakage from the pressure relief mechanism. Furthermore, during production, it is easier to ensure that the burst pressure of multiple battery cells produced is more consistent.

[0062] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned battery cell.

[0063] Thirdly, embodiments of this application also provide an electrical device, which includes the aforementioned battery cell, and the battery cell is used to provide electrical energy to the electrical device. Attached Figure Description

[0064] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0066] Figure 2 Exploded views of battery devices provided in some embodiments of this application;

[0067] Figure 3 A schematic diagram of the top structure of a battery cell provided in some embodiments of this application;

[0068] Figure 4 Exploded views of a single battery cell provided in some embodiments of this application;

[0069] Figure 5 A schematic diagram of the bottom structure of a battery cell provided in some embodiments of this application;

[0070] Figure 6 This is a schematic diagram of the structure of a pressure relief mechanism provided in some embodiments of this application;

[0071] Figure 7 A top view schematic diagram of a pressure relief mechanism provided in some embodiments of this application;

[0072] Figure 8 for Figure 7 A cross-sectional view at position AA in the middle;

[0073] Figure 9 Schematic diagrams of the pressure relief mechanism provided in other embodiments of this application;

[0074] Figure 10 A top view schematic diagram of a pressure relief mechanism provided in some other embodiments of this application;

[0075] Figure 11 for Figure 10 A cross-sectional view at position BB in the middle;

[0076] Figure 12 A top view schematic diagram of a pressure relief mechanism provided in some embodiments of this application;

[0077] Figure 13 for Figure 12 A cross-sectional view at position CC;

[0078] Figure 14 This application also provides structural schematic diagrams of pressure relief mechanisms in some embodiments;

[0079] Figure 15 This application also provides a top view schematic diagram of a pressure relief mechanism in some embodiments;

[0080] Figure 16 A cross-sectional view of a pressure relief mechanism provided in some embodiments of this application.

[0081] Icons: 1000 - Vehicle; 100 - Battery Unit; 10 - Housing; 11 - First Housing Body; 12 - Second Housing Body; 20 - Battery Cell; 21 - Housing; 211 - Wall; 212 - Bottom Wall; 213 - Side Wall; 215 - Housing; 2151 - Opening; 216 - End Cap; 22 - Electrode Assembly; 221 - Tab; 23 - Electrode Terminal; 24 - Current Collector; 25 - Pressure Relief Mechanism; 251 - Raised Section; 2511 - Arc-shaped Area; 25111 - First surface; 25112 - Second surface; 2512 - Transition zone; 252 - Weak section; 2521 - First weak segment; 2522 - Second weak segment; 2523 - Third weak segment; 2524 - Fourth weak segment; 253 - Connecting part; 254 - Second groove; 26 - Reinforcing part; 261 - First reinforcing part; 262 - Second reinforcing part; 263 - Converging area; 264 - First groove; 265 - Mid-section; 200 - Controller; 300 - Motor. Detailed Implementation

[0082] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0083] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0084] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0085] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0086] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0087] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0088] In this application, "multiple" means two or more (including two).

[0089] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0090] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0091] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0092] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0093] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0094] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0095] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in battery cells may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0096] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0097] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0098] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0099] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0100] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0101] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0102] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0103] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0104] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0105] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0106] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0107] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0108] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0109] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0110] In some implementations, the electrode assembly is a stacked structure.

[0111] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0112] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0113] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0114] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0115] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0116] In some implementations, the electrode assembly may be flat or polygonal in shape.

[0117] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0118] In some implementations, a battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes.

[0119] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, it can protect the electrode assembly and prevent, to some extent, electrolyte leakage. When the housing is a non-sealed structure, it can still protect the electrode assembly, and a sealing bag may be included between the housing and the electrode assembly to encapsulate the electrode assembly and electrolyte. Specifically, the sealing bag can be a bag-shaped insulating component or an aluminum-plastic film.

[0120] As an example, a battery cell can be a prismatic battery cell or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0121] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0122] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging multiple battery cells and fixing them together to form an independent module.

[0123] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0124] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cell assemblies housed within the housing.

[0125] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0126] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0127] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0128] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0129] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0130] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0131] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0132] The development of battery technology must consider multiple design factors simultaneously, such as energy density, discharge capacity, and charge / discharge rate. Additionally, cycle life must be considered. However, current battery cycle life is relatively short.

[0133] To improve the reliability of individual battery cells, existing technologies include setting up a pressure relief mechanism on the cell. This mechanism has a weak point that breaks when the internal pressure of the cell reaches the burst pressure, thereby releasing the internal pressure and reducing the risk of explosion or fire.

[0134] In related technologies, during the manufacturing of pressure relief mechanisms, a portion within the area enclosed by the weak point is raised in a direction away from the electrode assembly to form a raised structure. This creates pre-deformation on the inner side of the weak point, facilitating its cracking and pressure relief. Thus, under the same burst pressure, the thickness of the weak point can be greater. During normal use of the battery cell, the weak point is less likely to crack prematurely due to internal pressure changes or external impacts, reducing the risk of premature damage. However, during battery cell manufacturing or use, the raised structure is prone to collapse, causing changes in the battery cell's burst pressure and preventing proper pressure relief, resulting in poor battery cell reliability.

[0135] In view of this, this application provides a battery cell, which includes a casing, an electrode assembly, and a pressure relief mechanism. The casing has a wall, the electrode assembly is housed within the casing, and the pressure relief mechanism is disposed in the wall. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion and a raised portion. The weak portion is configured to be at least partially destroyed to release pressure when the pressure inside the casing reaches a threshold. The raised portion is located within the area enclosed by the weak portion and is a raised structure that bulges along a direction close to or away from the electrode assembly. The raised portion is provided with a reinforcing portion.

[0136] Existing pressure relief mechanisms, during pressure relief, gradually bulge from a flat structure away from the electrode assembly under the internal pressure of the battery cell. After bulging, they open to release pressure under the internal pressure of the battery cell. In the embodiment of this application, the bulge of the pressure relief mechanism bulges away from the electrode assembly, and the bulge forms a pre-deformation on the inner side of the weak part, thereby facilitating the cracking and pressure release of the weak part. In this way, under the same burst pressure, the thickness of the weak part can be greater. During normal use of the battery cell, the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impacts, which helps reduce the risk of premature damage to the weak part and improves the lifespan of the battery cell. The base material of the pressure relief mechanism is iron, which can effectively improve the structural strength of the weak part and reduce the risk of cracking under external forces, which helps reduce the risk of premature damage to the weak part and improves the lifespan and reliability of the battery cell. By setting a reinforcing part on the bulge, the bulge is strengthened, making it less prone to collapse. On the one hand, this allows the weak part to crack and release pressure in time when the internal pressure of the battery cell reaches the threshold, which helps improve the reliability of the battery cell. On the other hand, this design improves the structural consistency of the raised portions of multiple battery cells, thereby enhancing the consistency of their burst pressure. Compared to existing aluminum explosion-proof valves, the pressure relief mechanism provided in this embodiment has a smaller thickness in its weak point. During manufacturing, even a slight change in the thickness of this weak point can cause a significant change in the burst pressure of the battery cell. By making the raised portion bulge away from the electrode assembly, the thickness of the weak point can be increased under the same burst pressure. A thicker weak point is easier to manufacture, thus improving the consistency of the burst pressure of multiple battery cells. Furthermore, when the thickness of the weak point is small, the pressure relief mechanism can also be thinner to facilitate processing and reduce material costs. This increases the risk of the raised portion collapsing, thus requiring reinforcement to strengthen it and reduce the risk of collapse.

[0137] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells and battery devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0138] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0139] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery device 100 is disposed inside the vehicle 1000, and the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000.

[0140] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0141] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0142] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 may include a housing 10 and battery cells 20, the housing 10 being used to house the battery cells 20.

[0143] The housing 10 has an enclosed space inside for accommodating the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which are interlocked. The first housing body 11 and the second housing body 12 can have various shapes, such as cuboids or cylinders. The first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can also be a hollow structure open on one side. The open side of the second housing body 12 interlocks with the open side of the first housing body 11, thus forming a housing 10 with an enclosed space. Alternatively, the first housing body 11 can be a hollow structure open on one side, and the second housing body 12 can be a plate-like structure, with the second housing body 12 interlocked with the open side of the first housing body 11, thus forming a housing 10 with an accommodating chamber.

[0144] In the battery device 100, there can be one or more battery cells 20. If there are multiple battery cells 20, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Alternatively, multiple battery cells 20 can be first connected in series, parallel, or in a mixed configuration to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10. Another option is that all battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the whole consisting of all battery cells 20 is housed within the housing 10.

[0145] In some embodiments, the battery device 100 may further include a busbar component, through which multiple battery cells 20 can be electrically connected to each other to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0146] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 3 This is a schematic diagram of the top structure of a battery cell 20 provided in some embodiments of this application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a schematic diagram of the bottom structure of a battery cell 20 provided in some embodiments of this application. Figure 6 This is a schematic diagram of the structure of the pressure relief mechanism 25 provided in some embodiments of this application. Figure 7 This is a top view schematic diagram of the pressure relief mechanism 25 provided in some embodiments of this application. Figure 8 for Figure 7 A cross-sectional view at position AA. This application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a pressure relief mechanism 25. The housing 21 has a wall 211, the electrode assembly 22 is housed within the housing 21, and the pressure relief mechanism 25 is disposed on the wall 211. The base material of the pressure relief mechanism 25 is iron. The pressure relief mechanism 25 includes a weak portion 252 and a raised portion 251. The weak portion 252 is configured to be at least partially destroyed to release pressure when the pressure inside the housing 21 reaches a threshold. The raised portion 251 is located within the area enclosed by the weak portion 252 and is a raised structure that bulges along a direction close to or away from the electrode assembly 22. The raised portion 251 is provided with a reinforcing portion 26.

[0147] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0148] The housing 21 includes a housing 215 and an end cap 216. The housing 215 has a receiving space with an opening 2151 at one end for accommodating the electrode assembly 22. The end cap 216 is connected to the housing 215 and closes the opening 2151.

[0149] End cap 216 refers to a component that covers the opening 2151 of housing 215 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 216 can be adapted to the shape of housing 215 to fit it. Optionally, end cap 216 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that end cap 216 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved reliability. The material of end cap 216 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. Battery cell 20 also includes an insulating component disposed inside end cap 216. The insulating component can be used to isolate the electrical connection components inside housing 215 from end cap 216 to reduce the risk of short circuit. For example, the insulating component can be plastic, rubber, etc.

[0150] The housing 215 is a component used to cooperate with the end cap 216 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 215 and the end cap 216 can be independent components. An opening 2151 can be provided on the housing 215, and the end cap 216 can close the opening 2151 to form the internal environment of the battery cell 20. Alternatively, the end cap 216 and the housing 215 can be integrated. Specifically, the end cap 216 and the housing 215 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 215, the end cap 216 closes the housing 215. The housing 215 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the housing 215 can be determined according to the specific shape and size of the electrode assembly 22. The shell 215 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0151] Electrode assembly 22 is the component in the battery cell 20 where electrochemical reactions occur. The housing 215 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 22, while the portions of the positive and negative electrode sheets without active material each constitute tabs 221. The positive and negative tabs may be located together at one end of the main body or separately at both ends. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte.

[0152] In some embodiments, see Figure 4 As shown, the battery cell 20 may also include an electrode terminal 23, which is insulated and mounted on the housing 21 and electrically connected to the electrode assembly 22 to output or input electrical energy of the battery cell 20.

[0153] It should be noted that the electrode terminal 23 is insulated and mounted on the housing 21, meaning that there is no electrical connection between the electrode terminal 23 and the housing 21.

[0154] Among them, Figure 3 and Figure 4 In the battery cell 20, there are two electrode terminals 23, which are spaced apart on the end cap 216. Correspondingly, each electrode assembly 22 has two tabs 221, and the polarities of the two tabs 221 are opposite. The two electrode terminals 23 are electrically connected to the two tabs 221 of the electrode assembly 22 respectively, so as to realize the input or output of the positive and negative electrodes of the battery cell 20.

[0155] For example, the electrode terminal 23 can be made of various materials, such as copper, iron, aluminum, steel or aluminum alloy.

[0156] Optionally, the structure in which the electrode terminal 23 is mounted on the housing 21 can be varied; for example, in Figure 3 and Figure 4 In this embodiment, both electrode terminals 23 are mounted on the end cap 216 of the housing 21. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, both electrode terminals 23 may be mounted on the housing 215 of the housing 21. Similarly, one electrode terminal 23 may be mounted on the housing 215 of the housing 21, and the other electrode terminal 23 may be mounted on the end cap 216 of the housing 21.

[0157] In some embodiments, see Figure 4As shown, the battery cell 20 may also include two current collectors 24, both of which are disposed inside the housing 21. Each current collector 24 is used to connect an electrode terminal 23 and a tab 221 of the same polarity in multiple electrode assemblies 22, so as to realize the electrical connection between the electrode terminal 23 and the electrode assembly 22, which helps to reduce the assembly difficulty between the tab 221 and the electrode terminal 23.

[0158] For example, the material of the current collector 24 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0159] The wall portion 211 can be an end cap 216 of the outer casing 21, or it can be a wall of the housing 215 of the outer casing 21. For example, in... Figure 3 and Figure 4 In some embodiments, the wall portion 211 is the bottom wall 212 of the housing 215, which is disposed opposite to the end cap 216. In other embodiments, the wall portion 211 is the end cap 216. In still other embodiments, the wall portion 211 may also be a side wall 213 of the housing 215 that is adjacent to and connected to the end cap 216.

[0160] The pressure relief mechanism 25 is a component used to open when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, thereby releasing the internal pressure of the battery cell 20. The pressure relief mechanism 25 can be a component mounted on the wall portion 211, in which case the pressure relief mechanism 25 and the wall portion 211 are separately configured and connected. For example, the pressure relief mechanism 25 can be an explosion-proof plate mounted on the wall portion 211. The pressure relief mechanism 25 can also be part of the wall portion 211, in which case the pressure relief mechanism 25 and the wall portion 211 are integrally formed. The location of the pressure relief mechanism 25 can be used to determine which wall of the housing 21 is the wall portion 211. For example, when the pressure relief mechanism 25 is located on the end cap 216, then the end cap 216 is the wall portion 211. When the pressure relief mechanism 25 is located on the bottom wall 212 of the housing 215, then the bottom wall 212 is the wall portion 211. When the pressure relief mechanism 25 is located on the side wall 213 of the housing 215, then the side wall 213 is the wall portion 211.

[0161] "The base material of the pressure relief mechanism 25 is iron" means that iron is the material with the highest mass percentage in the pressure relief mechanism 25. For example, the material of the pressure relief mechanism 25 can be carbon steel or stainless steel.

[0162] The pressure relief mechanism 25 includes a weak portion 252, which serves to relieve pressure. When the internal pressure or temperature of the battery cell 20 reaches a threshold, the pressure relief mechanism 25 can rupture along the weak portion 252 to release the internal pressure of the battery cell 20. For example, when the internal pressure of the battery cell 20 reaches the explosion pressure, the weak portion 252 ruptures under the action of the discharge materials (gas, electrolyte, etc.) inside the battery cell 20, allowing the discharge materials inside the battery cell 20 to be discharged smoothly.

[0163] The weak part 252 can be a ring structure, for example, the weak part 252 can be in the shape of a circular ring or an elliptical ring. The weak part 252 can also be a non-ring structure, for example, the weak part 252 can be C-shaped, U-shaped, etc.

[0164] The raised portion 251 is located inside the weak portion 252. The area enclosed by the weak portion 252 is the area where the pressure relief mechanism 25 forms an opening after the weak portion 252 is damaged by the gas inside the outer casing 21. When the weak portion 252 has a ring-shaped structure, the area enclosed by the weak portion 252 is the area within the ring-shaped structure. When the weak portion 252 has a non-ring-shaped structure, the area enclosed by the weak portion 252 is the area inside the ring formed by the weak portion 252 itself and the lines connecting its two ends. The area enclosed by the weak portion 252 includes the raised portion 251. In other words, the area enclosed by the weak portion 252 can be a partial raised portion 251 formed by bulging away from the electrode assembly 22, or the entire area enclosed by the weak portion 252 can be a raised portion 251 formed by bulging away from the electrode assembly 22.

[0165] The raised portion 251 is a raised structure that rises in a direction away from the electrode assembly 22. The raised structure is a structure in which both the inner and outer surfaces are arched in a direction away from the electrode assembly 22.

[0166] A reinforcing portion 26 is disposed on the raised portion 251 to strengthen it. The reinforcing portion 26 increases the rigidity of the raised portion 251 and enhances its resistance to deformation, thereby improving the overall resistance to deformation of the raised portion 251. The reinforcing portion 26 can be a closed structure extending along a closed trajectory; for example, it can be annular, elliptical, or racetrack-shaped. Alternatively, it can be a non-closed structure with gaps at both ends; for example, it can be an arc-shaped structure. The reinforcing portion 26 and the raised portion 251 can be integrally formed, for example, by stamping to create the reinforcing portion 26 on the raised portion 251, making them integrally formed. Alternatively, the reinforcing portion 26 and the raised portion 251 can be separately disposed and connected, for example, by welding.

[0167] In existing pressure relief mechanisms, the pressure relief mechanism 25 gradually bulges from a flat structure away from the electrode assembly 22 under the internal pressure of the battery cell 20 during pressure relief. After bulging, it opens to release pressure under the internal pressure of the battery cell 20. In this embodiment, the bulge 251 of the pressure relief mechanism 25 bulges away from the electrode assembly 22, and the bulge 251 forms a pre-deformation on the inner side of the weak portion 252, thereby facilitating the cracking and pressure relief of the weak portion 252. In this way, under the same burst pressure, the thickness of the weak portion 252 can be greater. During normal use of the battery cell 20, the weak portion 252 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impacts, which helps reduce the risk of premature damage to the weak portion 252 and improves the lifespan of the battery cell 20. The base material of the pressure relief mechanism 25 is iron, which can effectively improve the structural strength of the weak portion 252, reduce the risk of cracking of the weak portion 252 under external forces, and improve the service life and reliability of the battery cell 20. By providing a reinforcing portion 26 on the raised portion 251, the raised portion 251 is strengthened, making it less prone to collapse. On the one hand, this allows the weak portion 252 to crack and release pressure in time when the internal pressure of the battery cell 20 reaches the threshold, thus improving the reliability of the battery cell 20. On the other hand, it improves the structural consistency of the raised portions 251 of multiple manufactured battery cells 20, thereby improving the consistency of the explosion pressure of multiple battery cells 20. Compared with the aluminum explosion-proof valve in the prior art, the thickness of the weak portion 252 of the pressure relief mechanism 25 provided in this application embodiment is smaller. During manufacturing, even a slight change in the thickness of the weak portion 252 will result in a large change in the explosion pressure of the battery cell 20. By making the raised portion 251 bulge in a direction away from the electrode assembly 22, the thickness of the weak portion 252 can be increased under the same explosion pressure. The larger the thickness of the weak portion 252, the easier it is to manufacture, thus improving the consistency of the explosion pressure of multiple battery cells 20. In addition, when the thickness of the weak part 252 is small, the thickness of the pressure relief mechanism 25 will also be thinner in order to facilitate processing and reduce material costs. As a result, the risk of the raised part 251 collapsing is greater. Therefore, it is more necessary to set up the reinforcing part 26 to strengthen the raised part 251, thereby reducing the risk of the raised part 251 collapsing.

[0168] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 In some embodiments, the hardness of the reinforcing portion 26 is greater than the hardness of the area of ​​the raised portion 251 where the reinforcing portion 26 is not provided.

[0169] The hardness of the reinforcing part 26 is greater than the hardness of the area of ​​the raised part 251 without the reinforcing part 26. Both the hardness of the reinforcing part 26 and the hardness of the area of ​​the raised part 251 without the reinforcing part 26 can be considered Vickers hardness. Vickers hardness is determined by pressing a diamond pyramid indenter with a 136-degree angle between its opposite faces into the surface of the test sample under a specified load. After holding the indenter for a certain period and then removing the load, the diagonal length of the indentation is measured, the surface area of ​​the indentation is calculated, and finally, the average pressure on the indentation surface area is determined. This is the Vickers hardness value of the metal, denoted by the symbol HV. In actual measurements, calculation is not required; instead, the hardness value is directly obtained from a table based on the measured diagonal length of the indentation.

[0170] By making the hardness of the reinforcing part 26 greater than the hardness of the area of ​​the raised part 251 where the reinforcing part 26 is not provided, the strength of the reinforcing part 26 can be increased accordingly, thereby improving the reinforcing effect of the reinforcing part 26 on the raised part 251 and making the raised part 251 less prone to collapse.

[0171] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 In some embodiments, the raised portion 251 includes an arcuate region 2511, the length direction of which is a first direction, and any two cross sections of the arcuate region 2511 perpendicular to the first direction are identical first arcuate shapes, the first direction being perpendicular to the thickness direction of the wall portion 211. The reinforcing portion 26 is at least partially disposed in the arcuate region 2511.

[0172] Please refer to Figure 6 , Figure 7 and Figure 8 The first direction is the X direction shown in the figure, and the thickness direction of the wall 211 is the Z direction shown in the figure.

[0173] The arc-shaped region 2511 is the arc-shaped portion of the raised portion 251. The arc-shaped region 2511 extends along a first direction, that is, the length direction of the arc-shaped region 2511 is the first direction.

[0174] Please refer to Figure 8 Any two cross sections of the arc-shaped region 2511 perpendicular to the first direction are identical first arc shapes. The first arc shape can be either circular or parabolic. In other words, the arc-shaped region 2511 has the same first arc shape along multiple different cross sections perpendicular to the first direction. The arc-shaped region 2511 can be considered as being formed by extending a first arc shape along the first direction.

[0175] In some embodiments, a portion of the reinforcing portion 26 is located within the arcuate region 2511, while another portion of the reinforcing portion 26 is located outside the arcuate region 2511. In other embodiments, the reinforcing portion 26 is entirely located within the arcuate region 2511.

[0176] The arc-shaped region 2511 of the raised portion 251 is more prone to collapse. By providing at least a portion of the reinforcing portion 26 in the arc-shaped region 2511, the risk of collapse of the arc-shaped region 2511 is reduced, making the arc-shaped region 2511 less prone to abnormal deformation. On the one hand, this allows the weak portion 252 to crack and release pressure in time when the internal pressure of the battery cell 20 reaches the threshold, which is beneficial to improving the reliability of the battery cell 20. On the other hand, it makes the structure of the raised portion 251 of multiple battery cells 20 more consistent, thereby improving the consistency of the explosion pressure of multiple battery cells 20.

[0177] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 In some embodiments, the raised portion 251 further includes a transition region 2512, which connects the arcuate portion 2511 and the weak portion 252. The cross-section of the transition region 2512 parallel to the first direction is a second arcuate shape. Along the thickness direction of the wall portion 211, there is a height difference between the end of the second arcuate shape near the weak portion 252 and the end of the second arcuate shape near the arcuate portion 2511. Along the first direction, transition regions 2512 are provided at both ends of the arcuate portion 2511.

[0178] The transition region 2512 is the portion of the raised portion 251 that connects the arcuate region 2511 and the weak portion 252. The transition region 2512 can be directly connected to the weak portion 252, or it can be indirectly connected to the weak portion 252. For example, there is also a straight region between the weak portion 252 and the raised portion 251, through which the transition region 2512 is indirectly connected to the weak portion 252.

[0179] The cross-section of the transition region 2512 parallel to the first direction is a second arc shape, which can be either a circular arc or an elliptical arc. The second arc shape has a first end near the weak portion 252 and a second end near the arc-shaped region 2511, with a height difference between the first and second ends along the thickness direction of the wall portion 211. Optionally, along the thickness direction of the wall portion 211, the second end is further away from the electrode assembly 22 than the first end. Along the direction from the second end to the first end, the second arc shape gradually approaches the electrode assembly 22.

[0180] It should be noted that the second arc of any two cross sections parallel to the first direction in the transition zone 2512 can be different.

[0181] The raised portion 251 includes two transition regions 2512, which are connected to the two ends of the arcuate portion 2511 along the first direction.

[0182] The transition zone 2512 can connect the arc-shaped zone 2511 and the weak part 252, so that the arc-shaped zone 2511 can naturally transition to the weak part 252, which helps to reduce the risk of stress concentration in the pressure relief mechanism 25.

[0183] Please refer to Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 In some embodiments, the weak portion 252 includes a first weak segment 2521, a second weak segment 2522, and a third weak segment 2523. The first weak segment 2521 and the third weak segment 2523 are disposed opposite each other along a first direction. The second weak segment 2522 connects the first weak segment 2521 and the third weak segment 2523. The first weak segment 2521 and the third weak segment 2523 are arc-shaped, while the second weak segment 2522 is straight. One end of the arc-shaped region 2511 along a second direction is connected to the second weak segment 2522. One transition region 2512 is connected to the first weak segment 2521, and the other transition region 2512 is connected to the third weak segment 2523. The first direction, the second direction, and the thickness direction of the wall portion 211 are perpendicular to each other.

[0184] Please refer to Figure 6 , Figure 7 and Figure 8 The second direction is the Y direction shown in the figure.

[0185] The first weak segment 2521 and the third weak segment 2523 are arc segments, and the second weak segment 2522 is a straight segment. The first weak segment 2521 and the third weak segment 2523 are arranged opposite each other along a first direction, and the second weak segment 2522 extends along the first direction, connecting one end of the first weak segment 2521 and one end of the third weak segment 2523. Along a second direction, the first weak segment 2521 and the third weak segment 2523 are located on the same side of the second weak segment 2522.

[0186] One end of the arc-shaped region 2511 along the second direction can be directly connected to the second weak segment 2522, or the other end of the arc-shaped region 2511 along the second direction can be indirectly connected to the second weak segment 2522. For example, there is also a straight region between the arc-shaped region 2511 and the second weak segment 2522, and one end of the arc-shaped region 2511 along the second direction is indirectly connected to the second weak segment 2522 through this straight region.

[0187] The transition region 2512 near the first weak segment 2521 can be directly connected to the first weak segment 2521, or it can be indirectly connected to the first weak segment 2521. For example, there is also a straight region between the transition region 2512 near the first weak segment 2521 and the first weak segment 2521, and the transition region 2512 near the first weak segment 2521 is indirectly connected to the first weak segment 2521 through this straight region.

[0188] The transition region 2512 near the second weak segment 2522 can be directly connected to the third weak segment 2523, and the transition region 2512 near the first weak segment 2521 can also be indirectly connected to the third weak segment 2523. For example, there is also a straight region between the transition region 2512 near the first weak segment 2521 and the third weak segment 2523, and the transition region 2512 near the first weak segment 2521 is indirectly connected to the third weak segment 2523 through this straight region.

[0189] Please refer to Figure 6 , Figure 7 and Figure 8 In the embodiment shown in the figure, the pressure relief mechanism 25 further includes a connecting portion 253, which surrounds the outer side of the weak portion 252. The connecting portion 253 is integrally formed with the wall portion 211 or is separately provided and connected. Along the second direction, one end of the arc-shaped region 2511 away from the second weak segment 2522 is connected to the connecting portion 253.

[0190] One transition zone 2512 connects one end of the first weak section 2521 and the arc-shaped zone 2511 to facilitate the transition from one end of the arc-shaped zone 2511 to the first weak section 2521. Another transition zone 2512 connects the third weak section 2523 and the other end of the arc-shaped zone 2511 to facilitate the transition from the other end of the arc-shaped zone 2511 to the third weak section 2523, which helps reduce the risk of stress concentration in the pressure relief mechanism 25. One end of the arc-shaped zone 2511 along the second direction is connected to the second weak section 2522, thereby facilitating the opening of the weak section 252 to release pressure when the battery cell 20 is depressurized, as the raised portion 251 pulls on the weak portion 252.

[0191] Please refer to Figure 9 , Figure 10 and Figure 11 , Figure 9 This is a structural schematic diagram of the pressure relief mechanism 25 provided in some other embodiments of this application. Figure 10 This is a top view of a pressure relief mechanism 25 provided in some other embodiments of this application. Figure 11 for Figure 10A cross-sectional view at position BB. In some embodiments, the weak portion 252 includes a fourth weak segment 2524, which is straight, and the first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524 are connected end-to-end. Along the second direction, the end of the arcuate region 2511 away from the second weak segment 2522 is connected to the fourth weak segment 2524.

[0192] Both the fourth weak segment 2524 and the second weak segment 2522 are straight segments, extending along the first direction. Along the second direction, the fourth weak segment 2524 and the second weak segment 2522 are positioned opposite each other. The first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524 are sequentially connected end-to-end to form a ring structure. Please refer to... Figure 7 The weakest part, 252, is a runway-shaped structure.

[0193] Along the second direction, the arc-shaped region 2511 is located between the second weak segment 2522 and the fourth weak segment 2524. One end of the arc-shaped region 2511 along the second direction is directly or indirectly connected to the second weak segment 2522, and the other end of the arc-shaped region 2511 along the second direction is directly or indirectly connected to the fourth weak segment 2524.

[0194] The first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524 are connected end to end. When the battery cell 20 is depressurized, it can crack along at least one of the first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524, thereby opening a larger opening and achieving rapid depressurization. Along the second direction, the arc-shaped region 2511 connects the second weak segment 2522 and the fourth weak segment 2524, thereby facilitating the arc-shaped region 2511 to pull the second weak segment 2522 and the fourth weak segment 2524, thus facilitating the opening of the second weak segment 2522 and the fourth weak segment 2524 to depressurize.

[0195] Please refer to Figure 9 , Figure 10 and Figure 11 In some embodiments, the orthographic projection of the reinforcement 26 is arc-shaped in a projection plane perpendicular to the thickness direction of the wall portion 211.

[0196] "In the projection plane perpendicular to the thickness direction of the wall portion 211, the orthographic projection of the reinforcing portion 26 is arc-shaped." That is, the orthographic projection of the reinforcing portion 26 in the projection plane perpendicular to the thickness direction of the wall portion 211 is arc-shaped. It can be understood that the reinforcing portion 26 has an arc-shaped structure.

[0197] By making the orthographic projection of the reinforcing part 26 in the projection plane perpendicular to the thickness direction of the wall part 211 into an arc shape, the reinforcing part 26 has a better reinforcing effect, good structural stability, and is conducive to reducing stress concentration.

[0198] Please refer to Figure 9 , Figure 10 and Figure 11 In some embodiments, the raised portion 251 is provided with a plurality of reinforcing portions 26, including a first reinforcing portion 261 and a second reinforcing portion 262. In a projection plane perpendicular to the thickness direction of the wall portion 211, the openings of the orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 are arranged opposite to each other.

[0199] The raised portion 251 may be provided with two reinforcing portions 26, three reinforcing portions 26, four reinforcing portions 26 or more reinforcing portions 26.

[0200] Both the first reinforcing part 261 and the second reinforcing part 262 are arc-shaped structures. The central angle of the first reinforcing part 261 can be any angle less than 360°, such as an acute angle, a right angle, or an obtuse angle. The central angle of the second reinforcing part 262 can also be any angle less than 360°, such as an acute angle, a right angle, or an obtuse angle. The first reinforcing part 261 has two ends in the extending direction, and the line connecting the two ends of the first reinforcing part 261 forms an opening in the first reinforcing part 261. The second reinforcing part 262 has two ends in the extending direction, and the line connecting the two ends of the second reinforcing part 262 forms an opening in the second reinforcing part 262.

[0201] In the projection plane perpendicular to the thickness direction of the wall portion 211, the opening of the orthographic projection of the first reinforcing portion 261 is arranged opposite to the opening of the orthographic projection of the second reinforcing portion 262; that is, the orientation of the opening of the orthographic projection of the first reinforcing portion 261 is opposite to the orientation of the opening of the orthographic projection of the second reinforcing portion 262. Please refer to... Figure 7 In the projection plane perpendicular to the thickness direction of the wall portion 211, the orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 are arranged along the second direction, with the opening of the orthographic projection of the first reinforcing portion 261 facing to the left and the opening of the orthographic projection of the second reinforcing portion 262 facing to the right.

[0202] By providing multiple reinforcing portions 26 on the raised portion 251, the reinforcement effect of the raised portion 251 is improved. The orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 in a projection plane perpendicular to the thickness direction of the wall portion 211 are both arc-shaped. Furthermore, the openings of the orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 are arranged back-to-back in this manner. This increases the radiation range of the first and second reinforcing portions 261, expanding the reinforcement range of the raised portion 251 and making the raised portion 251 less prone to collapse. On one hand, this allows the weak portion 252 to crack and release pressure promptly when the internal pressure of the battery cell 20 reaches a threshold, thus improving the reliability of the battery cell 20. On the other hand, it improves the structural consistency of the raised portions 251 of the manufactured multiple battery cells 20, thereby improving the consistency of the detonation pressure of the multiple battery cells 20.

[0203] Please refer to Figure 9 , Figure 10 and Figure 11 In some embodiments, the raised portion 251 includes an arcuate region 2511 extending along a first direction. The arcuate region 2511 has an arcuate cross-section perpendicular to the first direction, and a reinforcing portion 26 is disposed in the arcuate region 2511. In a projection plane perpendicular to the thickness direction of the wall portion 211, the openings of the orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 are arranged opposite to each other along a second direction, and the first direction, the second direction, and the thickness direction of the wall portion 211 are perpendicular to each other.

[0204] In the projection plane perpendicular to the thickness direction of the wall portion 211, the orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 are arranged along the second direction. The first reinforcing portion 261 and the second reinforcing portion 262 can be directly connected, or the first reinforcing portion 261 and the second reinforcing portion 262 can be arranged at intervals.

[0205] In a projection plane perpendicular to the thickness direction of the wall portion 211, the orientation of the opening in the orthographic projection of the first reinforcing portion 261 is opposite to the orientation of the opening in the orthographic projection of the second reinforcing portion 262. Specifically, in a projection plane perpendicular to the thickness direction of the wall portion 211, the orientation of the opening in the orthographic projection of the first reinforcing portion 261 is the direction in which the second reinforcing portion 262 points to the first reinforcing portion 261, and the orientation of the opening in the orthographic projection of the second reinforcing portion 262 is the direction in which the first reinforcing portion 261 points to the second reinforcing portion 262. Please refer to... Figure 7 In the projection plane perpendicular to the thickness direction of the wall portion 211, the opening of the orthographic projection of the first reinforcing portion 261 faces to the left, and the opening of the orthographic projection of the second reinforcing portion 262 faces to the right.

[0206] The arc-shaped region 2511 of the raised portion 251 is more prone to collapse. By providing at least a portion of the reinforcing portion 26 in the arc-shaped region 2511, the risk of collapse is reduced, making the arc-shaped region 2511 less prone to abnormal deformation. In the projection plane perpendicular to the thickness direction of the wall portion 211, the openings of the orthographic projections of the first reinforcing portion 261 and the second reinforcing portion 262 are arranged opposite to each other along the second direction to further increase the radiation range of the first reinforcing portion 261 and the second reinforcing portion 262, increase the reinforcement range of the arc-shaped region 2511, make the arc-shaped region 2511 less prone to collapse, and improve the structural consistency of the raised portions 251 of the manufactured multiple battery cells 20, thereby helping to improve the consistency of the detonation pressure of the multiple battery cells 20.

[0207] In other embodiments, in a projection plane perpendicular to the thickness direction of the wall portion 211, the openings of the orthographic projection of the first reinforcing portion 261 and the openings of the orthographic projection of the second reinforcing portion 262 are arranged opposite to each other along a first direction.

[0208] Please refer to Figure 9 , Figure 10 and Figure 11 In some embodiments, the first reinforcing part 261 is connected to the second reinforcing part 262.

[0209] "The first reinforcing part 261 is connected to the second reinforcing part 262", meaning that the first reinforcing part 261 and the second reinforcing part 262 are directly connected.

[0210] By connecting the first reinforcing part 261 to the second reinforcing part 262, the reinforcing effect on the arc-shaped area 2511 is further enhanced.

[0211] Please refer to Figure 9 , Figure 10 and Figure 11 In some embodiments, the first reinforcing portion 261 and the second reinforcing portion 262 are connected to form a converging region 263, which passes through the mid-section 265 of the arc-shaped region 2511. The mid-section 265 is perpendicular to the second direction.

[0212] The convergence area 263 is a shared part of the first reinforcing section 261 and the second reinforcing section 262.

[0213] Mid-section 265 is a section passing through the centerline of the arc-shaped region 2511 and perpendicular to the second direction. Please refer to... Figure 11 , Figure 11 The midsection 265 is shown in dashed lines.

[0214] "The confluence region 263 passes through the mid-section 265 of the arc region 2511" means that the confluence region 263 intersects with the mid-section 265 of the arc region 2511.

[0215] The collection area 263 passes through the mid-section 265 of the arc-shaped area 2511. A portion of the first reinforcing part 261 is located on one side of the mid-section 265, and a portion of the second reinforcing part 262 is located on the other side of the mid-section 265. This provides a good reinforcing effect on both sides of the arc-shaped area 2511 located on the mid-section 265, resulting in better structural stability of the pressure relief mechanism 25.

[0216] Please refer to Figure 12 and Figure 13 , Figure 12 This is a top view of a pressure relief mechanism 25 provided in some embodiments of this application. Figure 13 for Figure 12 A cross-sectional view at position CC. In some other embodiments, the orthographic projections of the first reinforcing part 261 and the second reinforcing part 262 are spaced apart in a projection plane perpendicular to the thickness direction of the wall part 211.

[0217] When the orthographic projection of the first reinforcing part 261 and the orthographic projection of the second reinforcing part 262 are spaced apart in the projection plane perpendicular to the thickness direction of the wall part 211, the first reinforcing part 261 and the second reinforcing part 262 are spaced apart, that is, there is a gap between the first reinforcing part 261 and the second reinforcing part 262, and the first reinforcing part 261 and the second reinforcing part 262 are not directly connected.

[0218] Please refer to Figure 12 In the embodiment shown in the figure, the first reinforcing part 261 and the second reinforcing part 262 are spaced apart along the second direction.

[0219] The orthographic projections of the first reinforcing part 261 and the second reinforcing part 262 in the same plane perpendicular to the thickness direction of the wall part 211 are spaced apart to increase the radiation range of the first reinforcing part 261 and the second reinforcing part 262, thereby increasing the reinforcement range of the arc-shaped area 2511. This makes the arc-shaped area 2511 less prone to collapse and improves the structural consistency of the raised parts 251 of the multiple battery cells 20, which in turn helps to improve the consistency of the detonation pressure of the multiple battery cells 20.

[0220] Please refer to Figure 12 and Figure 13 In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion 211, the orthographic projection of the first reinforcing portion 261 and the orthographic projection of the second reinforcing portion 262 are located on both sides of the mid-section 265 of the arc-shaped region 2511, respectively, and the mid-section 265 is perpendicular to the second direction.

[0221] In the projection plane perpendicular to the thickness direction of the wall portion 211, the orthographic projection of the first reinforcing portion 261 is located on one side of the mid-section 265 of the arc-shaped region 2511, and the orthographic projection of the second reinforcing portion 262 is located on the other side of the mid-section 265 of the arc-shaped region 2511. Please refer to... Figure 13 In the projection plane perpendicular to the thickness direction of the wall portion 211, the orthographic projection of the first reinforcing portion 261 is located on the left side of the mid-section 265 of the arc-shaped region 2511 along the second direction, and the orthographic projection of the second reinforcing portion 262 is located on the right side of the mid-section 265 of the arc-shaped region 2511 along the second direction.

[0222] The first reinforcing part 261 and the second reinforcing part 262 are located on both sides of the middle section 265, respectively, so that the arc-shaped area 2511 located on both sides of the middle section 265 can play a good reinforcing effect, and thus the pressure relief mechanism 25 has better structural stability.

[0223] Please refer to Figure 12 and Figure 13 In some embodiments, along the first direction, the length of the arcuate region 2511 is L1, the length of the reinforcing portion 26 is L2, and L2 / L1 ≥ 0.6. The first direction is perpendicular to the thickness direction of the wall portion 211.

[0224] L1 represents the length of the arc-shaped region 2511 along the first direction, which is the distance between the two ends of the arc-shaped region 2511 along the first direction.

[0225] L2 represents the length of the reinforcing part 26 along the first direction. During measurement, the distance between the two ends of the reinforcing part 26 that are furthest apart along the first direction can be measured.

[0226] L2 / L1≥0.6 means that the ratio of the length of the reinforcing part 26 along the first direction to the length of the arc-shaped region 2511 along the first direction is greater than or equal to 0.6.

[0227] The ratio of the length of the reinforcing part 26 along the first direction to the length of the arc-shaped region 2511 along the first direction can be: L2 / L1 = 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0228] When L2 / L1≥0.6, the length of the reinforcing part 26 along the first direction is larger, and the radiation range of the reinforcing part 26 is larger, which is beneficial to increase the reinforcement range of the arc-shaped region 2511, making the arc-shaped region 2511 less prone to collapse, and making the structure of the raised part 251 of the multiple battery cells 20 more consistent, thereby helping to improve the consistency of the explosion pressure of the multiple battery cells 20.

[0229] Please refer to Figure 14 and Figure 15 , Figure 14The present application also provides a structural schematic diagram of the pressure relief mechanism 25 provided in some embodiments. Figure 15 This is a top view of a pressure relief mechanism 25 provided in some embodiments of this application. In some embodiments, along a first direction, a plurality of reinforcing portions 26 are provided in the arc-shaped region 2511 at intervals. The length of the arc-shaped region 2511 is L1, the sum of the lengths of the plurality of reinforcing portions 26 is L3, L3 / L1≥0.6, and the first direction is perpendicular to the thickness direction of the wall portion 211.

[0230] The arc-shaped area 2511 may be provided with two, three, four or more reinforcing parts 26, and the multiple reinforcing parts 26 are spaced apart along the first direction.

[0231] L3 represents the sum of the lengths of the plurality of reinforcing portions 26 spaced apart along the first direction along the first direction. Please refer to... Figure 15 The arc-shaped region 2511 is provided with three reinforcing portions 26 arranged at intervals along the first direction. The lengths of the three reinforcing portions 26 along the first direction are: L 31 L 32 and L 33 Then L3 = L 31 +L 32 +L 33 .

[0232] L3 / L1≥0.6 indicates that the ratio of the sum of the lengths of the multiple reinforcing parts 26 spaced apart along the first direction to the length of the arc-shaped region 2511 along the first direction is greater than or equal to 0.6.

[0233] The ratio of the sum of the lengths of the multiple reinforcing portions 26 spaced apart along the first direction to the length of the arc-shaped region 2511 along the first direction can be: L3 / L1 = 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, etc.

[0234] When L3 / L1≥0.6, the total length of the multiple reinforcing parts 26 along the first direction is large. The multiple reinforcing parts 26 work together to strengthen the arc-shaped region 2511, and the strengthening range of the arc-shaped region 2511 is large, making the arc-shaped region 2511 less prone to collapse. This results in better structural consistency of the raised parts 251 of the multiple battery cells 20, which is beneficial to improving the consistency of the explosion pressure of the multiple battery cells 20.

[0235] Please refer to Figure 14 and Figure 15 In some other embodiments, along the first direction, the arc-shaped region 2511 is provided with a plurality of first reinforcing parts 261 arranged at intervals, and the second reinforcing parts 262 are provided in a one-to-one correspondence with the first reinforcing parts 261.

[0236] The arc-shaped region 2511 may be provided with two, three, four, or more first reinforcing parts 261, with the multiple first reinforcing parts 261 spaced apart along a first direction. Correspondingly, the arc-shaped region 2511 is also provided with multiple second reinforcing parts 262, the number of which is the same as the number of first reinforcing parts 261, and each second reinforcing part 262 corresponds to one first reinforcing part 261.

[0237] By setting multiple first reinforcing parts 261 and multiple second reinforcing parts 262, with each first reinforcing part 261 and the second reinforcing part 262 corresponding to one another, the reinforcing effect on the arc-shaped area 2511 is further improved, and the risk of the arc-shaped area 2511 collapsing is reduced.

[0238] Please refer to this again. Figure 12 and Figure 13 In some embodiments, the protrusion 251 has a first surface 25111 facing or away from the electrode assembly 22, and the reinforcement 26 protrudes from the first surface 25111.

[0239] The first surface 25111 can be the surface of the raised portion 251 facing the electrode assembly 22, that is, the inner surface of the raised portion 251. The first surface 25111 can also be the surface of the raised portion 251 away from the electrode assembly 22, that is, the outer surface of the raised portion 251. Along the thickness direction of the wall portion 211, the reinforcing portion 26 protrudes from the first surface 25111.

[0240] The reinforcing portion 26 can be a protrusion extending from the first surface 25111. The reinforcing portion 26 strengthens the raised portion 251, improving its resistance to deformation and making it less prone to collapse. On the one hand, this allows the weak portion 252 to crack and release pressure in time when the internal pressure of the battery cell 20 reaches the threshold, which is beneficial to improving the reliability of the battery cell 20. On the other hand, it makes the structure of the raised portions 251 of multiple battery cells 20 more consistent, thereby improving the consistency of the explosion pressure of multiple battery cells 20.

[0241] Please refer to this again. Figure 12 and Figure 13 In some embodiments, the raised portion 251 has a second surface 25112 opposite to the first surface 25111. The raised portion 251 is provided with a first groove 264, which is recessed from the second surface 25112 in a direction close to the first surface 25111, and a reinforcing portion 26 protruding from the first surface 25111 is formed at a position corresponding to the first groove 264 on the raised portion 251.

[0242] The second surface 25112 is the surface of the raised portion 251 opposite to the first surface 25111. When the first surface 25111 is the surface of the raised portion 251 facing the electrode assembly 22, the second surface 25112 is the surface of the raised portion 251 facing away from the electrode assembly 22. When the first surface 25111 is the surface of the raised portion 251 facing away from the electrode assembly 22, the second surface 25112 is the surface of the raised portion 251 facing the electrode assembly 22.

[0243] The first groove 264 is a groove provided on the second surface 25112, and the shape of the first groove 264 is the same as the shape of the reinforcing part 26.

[0244] During molding, a first groove 264 can be formed on the second surface 25112 by stamping, thereby forming a reinforcing part 26 protruding from the first surface 25111. The molding method of the reinforcing part 26 is simple. The setting of the first groove 264 makes the raised part 251 form a recessed structure at the position where the reinforcing part 26 is set, so that the reinforcing part 26 has better resistance to deformation and improves the reinforcing effect of the reinforcing part 26 on the raised part 251.

[0245] Please refer to this again. Figure 12 and Figure 13 In some embodiments, the first surface 25111 is the surface of the raised portion 251 facing the electrode assembly 22, and the second surface 25112 is the surface of the raised portion 251 facing away from the electrode assembly 22.

[0246] When the first surface 25111 is the surface of the raised portion 251 facing the electrode assembly 22, and the second surface 25112 is the surface of the raised portion 251 facing away from the electrode assembly 22, the first groove 264 is recessed in the direction facing the electrode assembly 22, and the raised portion 251 is raised in the direction away from the electrode assembly 22. The recessed direction of the first groove 264 and the raised direction of the raised portion 251 are opposite, which is beneficial to optimize the force distribution.

[0247] Please refer to Figure 16 , Figure 16 This is a cross-sectional view of a pressure relief mechanism 25 provided in some embodiments of this application. In some embodiments, the protrusion 251 has a first surface 25111 facing or away from the electrode assembly 22, and a first groove 264 is formed on the first surface 25111. The protrusion 251 includes a body portion and a thinned portion located at the bottom of the first groove 264. The thinned portion is connected to the body portion, and the thickness of the thinned portion is less than the thickness of the body portion, while the hardness of the thinned portion is greater than the hardness of the body portion. The thinned portion forms a reinforcing portion 26.

[0248] The second surface 25112 can be the surface of the raised portion 251 facing the electrode assembly 22, that is, the inner surface of the raised portion 251. The second surface 25112 can also be the surface of the raised portion 251 away from the electrode assembly 22, that is, the outer surface of the raised portion 251.

[0249] The first groove 264 is a groove provided on the second surface 25112. The bottom wall of the first groove 264 is formed into a thinned part. The part of the raised part 251 that is not thinned by the first groove 264 is the main body. The thinned part and the main body can be directly connected or indirectly connected.

[0250] The maximum thickness of the thinned portion is less than the minimum thickness of the body portion, and the hardness of the thinned portion is greater than the hardness of the body portion.

[0251] The first groove 264 can be formed by stamping, so that the bottom wall of the first groove 264 forms the aforementioned thinned portion. In this way, the bottom wall of the first groove 264 will undergo cold work hardening (the grain arrangement changes, resulting in lattice distortion, which reduces the plasticity of the metal and increases the hardness of the material), thereby increasing the hardness of the thinned portion and correspondingly increasing the strength of the thinned portion, so that the thinned portion can serve as a reinforcing portion 26 to strengthen the raised portion 251.

[0252] Please refer to Figure 16 In some embodiments, the pressure relief mechanism 25 is provided with a second groove 254, the bottom wall of the second groove 254 includes a weak portion 252, and the first groove 264 and the second groove 254 are provided on the same side of the pressure relief mechanism 25.

[0253] The second groove 254 is a groove structure disposed on the pressure relief mechanism 25. In some embodiments, a portion of the bottom wall of the second groove 254 is a weak portion 252. In other embodiments, the entire bottom wall of the second groove 254 is a weak portion 252.

[0254] The second groove 254 can be formed in various ways, such as stamping or cold heading. Taking the stamping method as an example, the second groove 254 can be stamped on the pressure relief mechanism 25 along the thickness direction of the wall 211.

[0255] The first groove 264 and the second groove 254 are disposed on the same side of the pressure relief mechanism 25. For example, the first groove 264 and the second groove 254 may both be disposed on the side of the pressure relief mechanism 25 facing the electrode assembly 22. Alternatively, the first groove 264 and the second groove 254 may both be disposed on the side of the pressure relief mechanism 25 away from the electrode assembly 22.

[0256] By creating a pressure relief groove in the pressure relief mechanism 25, a weak portion 252 is formed on the pressure relief mechanism 25. When the battery cell 20 is depressurized, the pressure relief mechanism 25 splits along at least a portion of the weak portion 252. This method is simple, convenient, and low-cost. By placing the first groove 264 and the second groove 254 on the same side of the pressure relief mechanism 25, it is convenient to process the first groove 264 and the second groove 254 simultaneously, which helps to improve production efficiency and optimize the stress on the pressure relief mechanism 25.

[0257] Please refer to Figure 16 In some embodiments, the pressure relief mechanism 25 further includes a connecting portion 253, which surrounds the outer side of the weak portion 252. The connecting portion 253 is integrally formed with the wall portion 211 or is separately provided and connected. The connecting portion 253 at least partially protrudes in the direction close to the electrode assembly 22, and the weak portion 252 is connected to the portion of the connecting portion 253 closest to the electrode assembly 22.

[0258] The connecting portion 253 is located outside the weak portion 252. When the pressure relief mechanism 25 and the wall portion 211 are separately provided and connected, the connecting portion 253 is the part of the pressure relief mechanism 25 used to connect to the wall portion 211. When the pressure relief mechanism 25 and the wall portion 211 are integrally formed, the connecting portion 253 is integrally formed with the wall portion 211. When the weak portion 252 has a ring structure, the connecting portion 253 is the part of the pressure relief mechanism 25 located outside the ring structure. When the weak portion 252 has a non-ring structure, the connecting portion 253 is the part of the pressure relief mechanism 25 located outside the ring formed by the weak portion 252 itself and the lines connecting the two ends of the weak portion 252.

[0259] The connecting portion 253 protrudes at least partially in the direction close to the electrode assembly 22, and the raised portion 251 protrudes in the direction away from the electrode assembly 22. The protrusion direction of the connecting portion 253 is opposite to that of the raised portion 251, so that the raised portion 251 can be raised by utilizing the protrusion height of the connecting portion 253. This helps to reduce the height of the raised portion 251 beyond the surface of the connecting portion 253 furthest from the electrode assembly 22, reduce the occupation of the internal space of the battery cell 20 or the battery device 100, and help to improve the energy density of the battery cell 20 or the battery device 100. In addition, since the weak part 252 is connected to the part of the connecting part 253 closest to the electrode assembly 22, that is, the position of the weak part 252 is closer to the electrode assembly 22 than the connection position of the connecting part 253 and the wall part 211. Since one end of the connecting part 253 is constrained by the wall part 211, under the action of air pressure, the part of the connecting part 253 that bulges in the direction close to the electrode assembly 22 squeezes the weak part 252, thereby suppressing the cracking of the weak part 252, preventing the weak part 252 from creeping failure when the battery cell 20 is working normally, and effectively extending the life of the battery cell 20.

[0260] Please refer to Figure 16In some embodiments, the thickness of the raised portion 251 is H, which satisfies: 0.05mm≤H≤0.3mm.

[0261] H represents the thickness of the raised portion 251. During measurement, the thickness of the raised portion 251 can be obtained by measuring along a direction perpendicular to the surface of the raised portion 251. Alternatively, multiple measurements can be taken and the average value can be used as H.

[0262] The thickness of the raised portion 251 can be: H = 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, etc.

[0263] When H ≤ 0.3 mm, the thickness of the raised portion 251 is relatively thin, which helps to reduce the space occupied by the raised portion 251 on the internal space of the battery cell 20 or battery device 100, thereby improving the energy density of the battery cell 20. In addition, when the thickness of the raised portion 251 is relatively thin, the raised portion 251 is more prone to collapse, therefore, it is more necessary to provide a reinforcing portion 26 to strengthen the raised portion 251, thereby reducing the risk of collapse. When H ≥ 0.05 mm, the thickness of the raised portion 251 is not too small, and the strength of the raised portion 251 is not too low, making the raised portion 251 less susceptible to damage under external forces, which helps to improve the lifespan and reliability of the battery cell 20. Therefore, when 0.05 mm ≤ H ≤ 0.3 mm, it is beneficial to improve the energy density, lifespan, and reliability of the battery cell 20.

[0264] Optionally, 0.075mm ≤ H ≤ 0.25mm.

[0265] The thickness of the raised portion 251 can be: H = 0.075mm, 0.1mm, 0.125mm, 0.15mm, 0.175mm, 0.2mm, 0.225mm, 0.25mm, etc.

[0266] When H ≤ 0.25 mm, the thickness of the raised portion 251 is thinner, which is more conducive to reducing the space occupied by the raised portion 251 on the internal space of the battery cell 20 or battery device 100, thereby improving the energy density of the battery cell 20. In addition, when the thickness of the raised portion 251 is thinner, the raised portion 251 is more prone to collapse, therefore, it is more necessary to provide a reinforcing portion 26 to strengthen the raised portion 251, thereby reducing the risk of collapse. When H ≥ 0.075 mm, the thickness of the raised portion 251 is not too small, and the strength of the raised portion 251 is not too low, making the raised portion 251 less susceptible to damage under external forces, which is beneficial to improving the lifespan and reliability of the battery cell 20. Therefore, when 0.075 mm ≤ H ≤ 0.25 mm, it is beneficial to improve the energy density, lifespan, and reliability of the battery cell 20.

[0267] In some embodiments, the material of the pressure relief mechanism 25 includes at least one of stainless steel and carbon steel.

[0268] The pressure relief mechanism 25 can be made of carbon steel or stainless steel, and the carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel. For example, the material of the pressure relief mechanism 25 can be 304 stainless steel, 305 stainless steel, 316 stainless steel, etc.

[0269] Stainless steel and carbon steel have high strength, which can effectively improve the structural strength of the weak part 252, reduce the risk of the weak part 252 cracking under external force, reduce the risk of the weak part 252 being damaged prematurely, and improve the service life and reliability of the battery cell 20.

[0270] Optionally, the material of the pressure relief mechanism 25 includes at least one of SUS304 stainless steel, SUS305 stainless steel or SUS316L stainless steel.

[0271] 304 stainless steel, 305 stainless steel and 316 stainless steel have advantages such as corrosion resistance, high temperature resistance and good processing performance. The pressure relief mechanism 25 made of 304 stainless steel, 305 stainless steel or 316 stainless steel has high strength, which can effectively improve the structural strength of the weak part 252, reduce the risk of the weak part 252 cracking under external force, reduce the risk of the weak part 252 being damaged prematurely, improve the service life and reliability of the battery cell 20, and improve the consistency of the burst pressure of multiple battery cells 20.

[0272] In some embodiments, the pressure relief mechanism 25 is separately disposed from the wall portion 211, the wall portion 211 is provided with a pressure relief hole, and the pressure relief mechanism 25 is installed on the wall portion 211 and covers the pressure relief hole.

[0273] The phrase "pressure relief mechanism 25 and wall portion 211 are separately provided, wall portion 211 is provided with a pressure relief hole, and pressure relief mechanism 25 is installed on wall portion 211 and covers the pressure relief hole" means that during manufacturing, a pressure relief hole is provided on wall portion 211, and pressure relief mechanism 25 and wall portion 211 are provided separately and ultimately connected together. For example, pressure relief mechanism 25 can be welded to wall portion 211. Pressure relief mechanism 25 can be an explosion-proof plate installed on wall portion 211.

[0274] The pressure relief mechanism 25 is separately set and installed on the wall portion 211 to facilitate manufacturing.

[0275] In some embodiments, the base materials of the pressure relief mechanism 25 and the wall portion 211 are both iron, and the pressure relief mechanism 25 is welded to the wall portion 211.

[0276] "The base material of the wall portion 211 is iron" means that the material with the highest mass percentage in the wall portion 211 is iron. For example, the material of the wall portion 211 can be carbon steel or stainless steel, and the carbon steel can be low carbon steel, medium carbon steel or high carbon steel.

[0277] It should be noted that the material of the wall portion 211 includes at least one of stainless steel and carbon steel. If the wall portion 211 is the end cap 216 of the outer shell 21, the material of the end cap 216 includes at least one of stainless steel and carbon steel. If the wall portion 211 is a wall in the shell 215, the material of the shell 215 includes at least one of stainless steel and carbon steel.

[0278] In this embodiment, by setting the material of the wall portion 211 to at least one of stainless steel and carbon steel, since steel has the characteristic of high strength, the wall portion 211 made of steel has better strength, so that under the condition of a certain burst pressure of the battery cell 20, the wall portion 211 can be made thinner, which is beneficial to saving the space occupied by the wall portion 211.

[0279] Optionally, the material of the wall portion 211 includes at least one of SUS304 stainless steel, SUS305 stainless steel, or SUS316L stainless steel.

[0280] The base materials of the pressure relief mechanism 25 and the wall portion 211 are both iron, which makes it easier to weld the pressure relief mechanism 25 and the wall portion 211. This helps to reduce the phenomenon of welding cracks between the pressure relief mechanism 25 and the wall portion 211, thereby reducing the risk of leakage of the battery cell 20 and improving the reliability of the battery cell 20.

[0281] In other embodiments, the pressure relief mechanism 25 is integrally formed with the wall portion 211.

[0282] One-piece molding means that the wall portion 211 and the pressure relief mechanism 25 are provided as a single structure. For example, the pressure relief mechanism 25 can be formed on the wall portion 211 by means of stamping or cold forging.

[0283] The pressure relief mechanism 25 is integrally formed with the wall 211, eliminating the need for additional welding or bonding processes, which helps reduce the risk of leakage from the pressure relief mechanism 25. Furthermore, during production, it is easier to ensure that the burst pressure of multiple battery cells 20 produced is more consistent.

[0284] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0285] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0286] According to some embodiments of this application, please refer to Figures 3 to 16。

[0287] This application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and a pressure relief mechanism 25. The housing 21 has a wall 211, the electrode assembly 22 is housed within the housing 21, and the pressure relief mechanism 25 is disposed on the wall 211. The base material of the pressure relief mechanism 25 is iron. The pressure relief mechanism 25 includes a weak portion 252 and a raised portion 251. The weak portion 252 is configured to be at least partially destroyed to release pressure when the pressure inside the housing 21 reaches a threshold. The raised portion 251 is located within the area enclosed by the weak portion 252 and is a raised structure that bulges along a direction close to or away from the electrode assembly 22. The raised portion 251 is provided with a reinforcing portion 26. In conventional pressure relief mechanisms 25, during pressure relief, the flat structure gradually bulges away from the electrode assembly 22 under the action of internal pressure within the battery cell 20. After bulging, the pressure relief mechanism opens under the action of internal pressure within the battery cell 20. In this embodiment, the raised portion 251 of the pressure relief mechanism 25 protrudes in the direction away from the electrode assembly 22. The raised portion 251 forms a pre-deformation on the inner side of the weak portion 252, thereby facilitating the cracking and pressure relief of the weak portion 252. Thus, under the same burst pressure, the thickness of the weak portion 252 can be greater. During normal use of the battery cell 20, the weak portion 252 is less likely to crack prematurely due to internal pressure changes or external impacts, which helps reduce the risk of premature damage to the weak portion 252 and improves the lifespan of the battery cell 20. The base material of the pressure relief mechanism 25 is iron, which effectively improves the structural strength of the weak portion 252, reduces the risk of cracking under external force, and further improves the lifespan and reliability of the battery cell 20. By providing a reinforcing portion 26 on the raised portion 251, the raised portion 251 is strengthened, making it less prone to collapse. On the one hand, this allows the weak portion 252 to crack and release pressure in time when the internal pressure of the battery cell 20 reaches the threshold, thus improving the reliability of the battery cell 20. On the other hand, it improves the structural consistency of the raised portions 251 of multiple manufactured battery cells 20, thereby improving the consistency of the explosion pressure of multiple battery cells 20. Compared with the aluminum explosion-proof valve in the prior art, the thickness of the weak portion 252 of the pressure relief mechanism 25 provided in this application embodiment is smaller. During manufacturing, even a slight change in the thickness of the weak portion 252 will result in a large change in the explosion pressure of the battery cell 20. By making the raised portion 251 bulge in a direction away from the electrode assembly 22, the thickness of the weak portion 252 can be increased under the same explosion pressure. The larger the thickness of the weak portion 252, the easier it is to manufacture, thus improving the consistency of the explosion pressure of multiple battery cells 20.In addition, when the thickness of the weak part 252 is small, the thickness of the pressure relief mechanism 25 will also be thinner in order to facilitate processing and reduce material costs. As a result, the risk of the raised part 251 collapsing is greater. Therefore, it is more necessary to set up the reinforcing part 26 to strengthen the raised part 251, thereby reducing the risk of the raised part 251 collapsing.

[0288] The raised portion 251 includes an arc-shaped region 2511, the length direction of which is a first direction. Any two cross-sections of the arc-shaped region 2511 perpendicular to the first direction are identical arc shapes. The first direction is perpendicular to the thickness direction of the wall portion 211. A reinforcing portion 26 is at least partially disposed in the arc-shaped region 2511. The arc-shaped region 2511 of the raised portion 251 is more prone to collapse. By at least partially disposing the reinforcing portion 26 in the arc-shaped region 2511, the risk of collapse is reduced, making the arc-shaped region 2511 less prone to abnormal deformation. On one hand, this allows the weak portion 252 to crack and release pressure promptly when the internal pressure of the battery cell 20 reaches a threshold, thus improving the reliability of the battery cell 20. On the other hand, it improves the structural consistency of the raised portions 251 of multiple manufactured battery cells 20, thereby improving the consistency of the explosion pressure of the multiple battery cells 20.

[0289] The raised portion 251 also includes a transition region 2512, which connects the arc-shaped region 2511 and the weak portion 252. The cross-section of the transition region 2512 parallel to the first direction is a second arc shape. Along the thickness direction of the wall portion 211, there is a height difference between the end of the second arc shape near the weak portion 252 and the end of the second arc shape near the arc-shaped region 2511. Transition regions 2512 are provided at both ends of the arc-shaped region 2511 along the first direction. The transition region 2512 connects the arc-shaped region 2511 and the weak portion 252, allowing the arc-shaped region 2511 to transition naturally to the weak portion 252, which helps reduce the risk of stress concentration in the pressure relief mechanism 25.

[0290] The weak portion 252 includes a first weak segment 2521, a second weak segment 2522, and a third weak segment 2523. The first weak segment 2521 and the third weak segment 2523 are arranged opposite each other along a first direction. The second weak segment 2522 connects the first weak segment 2521 and the third weak segment 2523. The first weak segment 2521 and the third weak segment 2523 are arc-shaped, while the second weak segment 2522 is straight. One end of the arc-shaped region 2511 along a second direction is connected to the second weak segment 2522. One transition region 2512 is connected to the first weak segment 2521, and the other transition region 2512 is connected to the third weak segment 2523. The first direction, the second direction, and the thickness direction of the wall portion 211 are perpendicular to each other. One transition zone 2512 connects one end of the first weak section 2521 and the arc-shaped zone 2511 to facilitate the transition from one end of the arc-shaped zone 2511 to the first weak section 2521. Another transition zone 2512 connects the third weak section 2523 and the other end of the arc-shaped zone 2511 to facilitate the transition from the other end of the arc-shaped zone 2511 to the third weak section 2523, which helps reduce the risk of stress concentration in the pressure relief mechanism 25. One end of the arc-shaped zone 2511 along the second direction is connected to the second weak section 2522, thereby facilitating the opening of the weak section 252 to release pressure when the battery cell 20 is depressurized, as the raised portion 251 pulls on the weak portion 252.

[0291] The weak section 252 includes a fourth weak segment 2524, which is straight and connected end-to-end with the first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524. Along the second direction, the end of the arc-shaped region 2511 furthest from the second weak segment 2522 is connected to the fourth weak segment 2524. Since the first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524 are connected end-to-end, when the battery cell 20 is depressurized, it can crack along at least one of the first weak segment 2521, the second weak segment 2522, the third weak segment 2523, and the fourth weak segment 2524, thereby opening a larger opening and achieving rapid depressurization. Along the second direction, the arc-shaped area 2511 connects the second weak section 2522 and the fourth weak section 2524, thereby facilitating the arc-shaped area 2511 to pull the second weak section 2522 and the fourth weak section 2524, thus facilitating the opening and pressure relief of the second weak section 2522 and the fourth weak section 2524.

[0292] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, include: The outer shell has walls; Electrode assembly, housed within the housing; A pressure relief mechanism is disposed on the wall portion. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion and a raised portion. The weak portion is configured to be at least partially destroyed to release the pressure when the pressure inside the housing reaches a threshold. The raised portion is located in the area enclosed by the weak portion. The raised portion is a raised structure that rises in a direction away from the electrode assembly. The raised portion is provided with a reinforcing portion.

2. The battery cell of claim 1, wherein, The hardness of the reinforcing part is greater than the hardness of the area of ​​the raised part where the reinforcing part is not provided.

3. The battery cell according to claim 1, characterized in that, The raised portion includes an arc-shaped area, the length direction of the arc-shaped area is a first direction, and any two cross sections of the arc-shaped area perpendicular to the first direction are the same first arc shape, and the first direction is perpendicular to the thickness direction of the wall portion; The reinforcing part is at least partially disposed in the arc-shaped area.

4. The battery cell according to claim 3, characterized in that, The raised portion further includes a transition zone, which connects the arc-shaped region and the weak portion. The cross-section of the transition zone parallel to the first direction is a second arc shape. Along the thickness direction of the wall portion, there is a height difference between the end of the second arc shape near the weak portion and the end of the second arc shape near the arc-shaped region. The transition zone is provided at both ends of the arc-shaped region along the first direction.

5. The battery cell according to claim 4, characterized in that, The weak portion includes a first weak segment, a second weak segment, and a third weak segment. The first weak segment and the third weak segment are arranged opposite to each other along the first direction. The second weak segment connects the first weak segment and the third weak segment. The first weak segment and the third weak segment are arc-shaped, and the second weak segment is straight. One end of the arc-shaped region along the second direction is connected to the second weak segment, one transition region is connected to the first weak segment, and the other transition region is connected to the third weak segment. The first direction, the second direction, and the thickness direction of the wall are perpendicular to each other.

6. The battery cell according to claim 5, characterized in that, The weak part includes a fourth weak segment, which is straight, and the first weak segment, the second weak segment, the third weak segment and the fourth weak segment are connected end to end; Along the second direction, the end of the arc-shaped region away from the second weak segment is connected to the fourth weak segment.

7. The battery cell according to claim 1, characterized in that, In a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the reinforcing portion is an arc shape.

8. The battery cell according to claim 7, characterized in that, The raised portion is provided with a plurality of reinforcing portions, including a first reinforcing portion and a second reinforcing portion. In a projection plane perpendicular to the thickness direction of the wall portion, the openings of the orthographic projections of the first reinforcing portion and the openings of the orthographic projections of the second reinforcing portion are arranged back to back.

9. The battery cell according to claim 8, characterized in that, The raised portion includes an arc-shaped area, which extends along a first direction and has an arc-shaped cross-section perpendicular to the first direction. The reinforcing portion is disposed in the arc-shaped area. In a projection plane perpendicular to the thickness direction of the wall portion, the openings of the orthographic projections of the first reinforcement portion and the second reinforcement portion are arranged opposite to each other along the second direction, and the first direction, the second direction, and the thickness direction of the wall portion are perpendicular to each other.

10. The battery cell according to claim 9, characterized in that, The first reinforcing part is connected to the second reinforcing part.

11. The battery cell according to claim 10, characterized in that, The first reinforcing part and the second reinforcing part are connected to form a converging area, which passes through the mid-section of the arc-shaped area and the mid-section is perpendicular to the second direction.

12. The battery cell according to claim 9, characterized in that, In a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projections of the first reinforcing portion and the second reinforcing portion are spaced apart.

13. The battery cell according to claim 12, characterized in that, In a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projections of the first reinforcing portion and the second reinforcing portion are located on both sides of the mid-section of the arc-shaped region, and the mid-section is perpendicular to the second direction.

14. The battery cell according to claim 9, characterized in that, Along the first direction, the length of the arc-shaped region is L1, the length of the reinforcing part is L2, L2 / L1≥0.6, and the first direction is perpendicular to the thickness direction of the wall part.

15. The battery cell according to claim 9, characterized in that, Along the first direction, the arc-shaped region is provided with a plurality of reinforcing parts arranged at intervals. The length of the arc-shaped region is L1, the sum of the lengths of the plurality of reinforcing parts is L3, L3 / L1≥0.6, and the first direction is perpendicular to the thickness direction of the wall.

16. The battery cell according to claim 9, characterized in that, Along the first direction, the arc-shaped area is provided with a plurality of first reinforcing parts arranged at intervals, and the second reinforcing parts are provided in a one-to-one correspondence with the first reinforcing parts.

17. The battery cell according to claim 1, characterized in that, The raised portion has a first surface facing or away from the electrode assembly, and the reinforcing portion protrudes from the first surface.

18. The battery cell according to claim 17, characterized in that, The raised portion has a second surface opposite to the first surface, and the raised portion is provided with a first groove. The first groove is recessed from the second surface in a direction close to the first surface, and a reinforcing portion protruding from the first surface is formed at a position on the raised portion corresponding to the first groove.

19. The battery cell according to claim 18, characterized in that, The first surface is the surface of the raised portion facing the electrode assembly, and the second surface is the surface of the raised portion away from the electrode assembly.

20. The battery cell according to claim 1, characterized in that, The raised portion has a second surface facing or away from the electrode assembly, the second surface having a first groove, the raised portion including a body portion and a thinned portion located at the bottom of the first groove, the thinned portion being connected to the body portion, the thickness of the thinned portion being less than the thickness of the body portion, the hardness of the thinned portion being greater than the hardness of the body portion, and the thinned portion forming the reinforcing portion.

21. The battery cell according to any one of claims 18-20, characterized in that, The pressure relief mechanism is provided with a second groove, the bottom wall of which includes the weak part, and the first groove and the second groove are located on the same side of the pressure relief mechanism.

22. The battery cell according to any one of claims 1-20, characterized in that, The pressure relief mechanism further includes a connecting portion, which surrounds the outside of the weak portion. The connecting portion is integrally formed with the wall portion or is separately provided and connected. The connecting portion at least partially protrudes in the direction close to the electrode assembly, and the weak portion is connected to the part of the connecting portion closest to the electrode assembly.

23. The battery cell according to any one of claims 1-20, characterized in that, The thickness of the raised portion is H, which satisfies the condition: 0.05mm≤H≤0.3mm.

24. The battery cell according to claim 23, characterized in that, 0.075mm≤H≤0.25mm.

25. The battery cell according to any one of claims 1-20, characterized in that, The pressure relief mechanism is made of either stainless steel or carbon steel.

26. The battery cell according to any one of claims 1-20, characterized in that, The pressure relief mechanism is made of one of the following materials: 304 stainless steel, 305 stainless steel, and 316 stainless steel.

27. The battery cell according to any one of claims 1-20, characterized in that, The pressure relief mechanism is separately disposed from the wall portion, the wall portion is provided with a pressure relief hole, and the pressure relief mechanism is installed on the wall portion and covers the pressure relief hole.

28. The battery cell according to claim 27, characterized in that, Both the pressure relief mechanism and the base material of the wall are made of iron, and the pressure relief mechanism is welded to the wall.

29. The battery cell according to any one of claims 1-20, characterized in that, The pressure relief mechanism is integrally formed with the wall portion.

30. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-29.

31. An electrical device, characterized in that, Includes a battery cell according to any one of claims 1-29, the battery cell being used to provide electrical energy to the electrical device.

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