Battery cell, battery device, and electric device

Abstract

The present application provides a battery cell, a battery device, and an electric device. The battery cell comprises a casing and a pressure relief mechanism. The casing is provided with a wall portion, the wall portion is provided with a pressure relief hole, and the pressure relief hole passes through the wall portion in the thickness direction of the wall portion. The pressure relief hole comprises a plurality of hole sections arranged in the thickness direction of the wall portion, the plurality of hole sections including a first hole section and a second hole section adjacent to each other, and a hole wall surface of the first hole section and a hole wall surface of the second hole section being connected by means of a first stepped surface. The area of the cross section of the second hole section is greater than the area of the cross section of the first hole section, and the cross sections are perpendicular to the thickness direction of the wall portion. The pressure relief mechanism is at least partially located in the second hole section and is arranged facing the first stepped surface, and the projection of the pressure relief mechanism in the thickness direction of the wall portion covers the first hole section. In the thickness direction of the wall portion, there is a first gap between the pressure relief mechanism and the first stepped surface. When the pressure relief mechanism deforms, the connecting position between the hole wall surface of the first hole section and the first stepped surface is not easily collided, and the pressure relief mechanism is not easily opened in advance.

Description

Battery cells, battery packs and electrical devices 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, current battery reliability is relatively poor.

[0003] Summary of the Invention

[0004] 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.

[0005] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a housing and a pressure relief mechanism. The housing has a wall portion, and the wall portion is provided with a pressure relief hole. The pressure relief hole penetrates the wall portion along its thickness direction. The pressure relief hole includes a plurality of hole segments arranged along the thickness direction of the wall portion. The plurality of hole segments include adjacent first hole segments and second hole segments. The hole wall surfaces of the first hole segment and the hole wall surfaces of the second hole segment are connected by a first step surface. The cross-sectional area of ​​the second hole segment is larger than the cross-sectional area of ​​the first hole segment, and the cross-section is perpendicular to the thickness direction of the wall portion. The pressure relief mechanism is at least partially located within the second hole segment and is disposed facing the first step surface. The projection of the pressure relief mechanism along the thickness direction of the wall portion covers the first hole segment. Wherein, along the thickness direction of the wall portion, there is a first gap between the pressure relief mechanism and the first step surface.

[0006] In the above technical solution, by accommodating the pressure relief mechanism within the second bore section, on the one hand, the height of the pressure relief mechanism protruding from the wall can be reduced, lowering the risk of interference between the pressure relief mechanism and other components, and reducing the space occupied by the pressure relief mechanism, which is beneficial to improving the energy density of the battery cell. On the other hand, the second bore section can position the pressure relief mechanism, simplifying assembly. Furthermore, when the pressure relief mechanism is connected to the wall by welding, the first step surface can block the laser, thereby reducing the risk of laser damage to other components. Moreover, by creating a first gap between the pressure relief mechanism and the first step surface, when the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to collide with the connection point between the bore wall of the first bore section and the first step surface, reducing the likelihood of premature valve opening and improving the reliability of the battery cell.

[0007] As an optional technical solution in this application embodiment, the size of the first gap along the thickness direction of the wall is H1, which satisfies: 0.05mm≤H1≤1mm, and optionally, 0.1mm≤H1≤0.5mm.

[0008] In the above technical solution, when H1 ≥ 0.05 mm, the dimension of the first gap along the thickness direction of the wall is relatively large, and the pressure relief mechanism is far from the first step surface. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to collide with the connection position between the hole wall surface of the first hole section and the first step surface, thus preventing premature valve opening and improving the reliability of the battery cell. When H1 ≤ 1 mm, the dimension of the first gap along the thickness direction of the wall is not too large, which helps to reduce space occupation and increase the energy density of the battery cell. Therefore, when 0.05 mm ≤ H1 ≤ 1 mm, both the reliability and energy density of the battery cell can be balanced.

[0009] When H1 ≥ 0.1 mm, the first gap has a larger dimension along the thickness direction of the wall, and the pressure relief mechanism is farther from the first step surface. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to collide with the connection between the hole wall and the first step surface of the first hole section, and less likely to cause premature valve opening, which is more conducive to improving the reliability of the battery cell. When H1 ≤ 0.5 mm, the first gap is not too large along the thickness direction of the wall, which helps to reduce space occupation and improve the energy density of the battery cell. Therefore, when 0.1 mm ≤ H1 ≤ 0.5 mm, it is better to balance the reliability and energy density of the battery cell.

[0010] As an optional technical solution in this application embodiment, the battery cell includes a protective member, which is disposed on the wall portion and located on the side of the pressure relief mechanism away from the first hole segment; along the thickness direction of the wall portion, the projection of the protective member covers the pressure relief mechanism, and there is a second gap between the pressure relief mechanism and the protective member.

[0011] In the above technical solution, by setting up a protective component, on the one hand, the risk of the pressure relief mechanism being subjected to external forces on the side away from the first orifice section can be reduced, making it less likely for the pressure relief mechanism to open the valve prematurely, which is beneficial to improving the reliability of the battery cell. On the other hand, the protective component can block impurities, making it less likely for impurities to fall onto the pressure relief mechanism and affect its normal valve opening, which is beneficial to improving the reliability of the battery cell. In addition, by setting a second gap between the pressure relief mechanism and the protective component, when the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely for the pressure relief mechanism to interfere with the protective component. When the battery cell is depressurized, it is also beneficial to allow the pressure relief mechanism to open a larger opening, thereby allowing the battery cell to depressurize quickly, which is beneficial to improving the reliability of the battery cell.

[0012] As an optional technical solution in this application embodiment, the size of the second gap along the thickness direction of the wall is H2, which satisfies: 0.05mm≤H2≤0.3mm, and optionally, 0.1mm≤H2≤0.25mm.

[0013] In the above technical solution, when H2 ≥ 0.05 mm, the second gap has a larger dimension along the thickness direction of the wall, and the pressure relief mechanism is farther from the protective component. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to interfere with the protective component. During battery cell pressure relief, it also allows the pressure relief mechanism to open a larger opening, enabling rapid pressure relief and improving the reliability of the battery cell. When H2 ≤ 0.3 mm, the second gap is not too large along the thickness direction of the wall, which helps reduce space occupation and increase the energy density of the battery cell. Therefore, when 0.05 mm ≤ H2 ≤ 0.3 mm, both the reliability and energy density of the battery cell can be balanced.

[0014] When H2 ≥ 0.1 mm, the second gap is larger along the thickness direction of the wall, and the pressure relief mechanism is farther from the protective component. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to interfere with the protective component. During battery cell pressure relief, it also allows the pressure relief mechanism to open a larger opening, enabling rapid pressure relief and improving battery cell reliability. When H2 ≤ 0.25 mm, the second gap is not too large along the thickness direction of the wall, which helps reduce space occupation and increase the energy density of the battery cell. Therefore, when 0.1 mm ≤ H2 ≤ 0.25 mm, both battery cell reliability and energy density can be balanced.

[0015] As an optional technical solution in this application embodiment, the plurality of hole segments include a third hole segment adjacent to the second hole segment, the second hole segment connects the first hole segment and the third hole segment, and the cross-sectional area of ​​the third hole segment is larger than the cross-sectional area of ​​the second hole segment; the protective member is disposed on the side of the third hole segment away from the second hole segment and covers the third hole segment.

[0016] In the above technical solution, by setting a third hole section, on the one hand, the third hole section can keep the protective component away from the pressure relief mechanism, that is, at least part of the third hole section can serve as a second gap. On the other hand, a part of the pressure relief mechanism can be accommodated in the third hole section, which helps to reduce the depth requirement of the second hole section, thereby facilitating processing and manufacturing.

[0017] As an optional technical solution in this application embodiment, a portion of the pressure relief mechanism is accommodated in the second hole section, and another portion of the pressure relief mechanism is accommodated in the third hole section.

[0018] In the above technical solution, by accommodating a part of the pressure relief mechanism in the second hole section and another part of the pressure relief mechanism in the third hole section, it is beneficial to reduce the depth requirement of the second hole section, thereby facilitating processing and manufacturing.

[0019] As an optional technical solution in this application embodiment, the wall is provided with a flow guiding channel, which connects the third hole section and the outside of the outer shell.

[0020] In the above technical solution, by setting a flow channel, when the battery cell is depressurized, the depressurization mechanism opens, and the fluid medium inside the battery cell can be released to the outside of the casing through the first orifice, the depressurization mechanism, the third orifice, and the flow channel, thereby achieving depressurization.

[0021] As an optional technical solution in this application embodiment, the plurality of hole segments include a fourth hole segment adjacent to the third hole segment, the third hole segment connects the second hole segment and the fourth hole segment, and the cross-sectional area of ​​the fourth hole segment is larger than the cross-sectional area of ​​the third hole segment; the protective member is at least partially accommodated in the fourth hole segment.

[0022] In the above technical solution, by having the protective component at least partially accommodated within the fourth hole segment, it is beneficial to reduce the height of the protective component protruding from the surface of the wall away from the interior of the outer casing. On the one hand, this helps to reduce the volume occupied by the protective component in the battery device, which is beneficial to improving the energy density of the battery device. On the other hand, it helps to reduce the risk of interference between the protective component and other components. In addition, the fourth hole segment can, to a certain extent, position the protective component, thereby facilitating its rapid installation.

[0023] As an optional technical solution in this application embodiment, the protective member is completely accommodated within the fourth hole segment.

[0024] In the above technical solution, by completely housing the protective component within the fourth hole section, it is beneficial to reduce the volume occupied by the protective component on the battery device and improve the energy density of the battery device. On the other hand, it is beneficial to reduce the risk of interference between the protective component and other components.

[0025] As an optional technical solution in this application embodiment, the hole wall surface of the third hole segment and the hole wall surface of the fourth hole segment are connected by a second step surface, and the protective member abuts against the second step surface.

[0026] In the above technical solution, by having the protective component abut against the second step surface, on the one hand, the installation of the protective component is simpler, and the relative position of the protective component and the pressure relief mechanism is better fixed. On the other hand, it is more difficult for external impurities to enter the third hole section, making it less likely for impurities to fall onto the pressure relief mechanism and less likely to affect the normal opening of the valve of the pressure relief mechanism, which is conducive to improving the reliability of the battery cell.

[0027] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the wall portion has a first surface and a second surface opposite to each other, the pressure relief hole penetrates through the first surface and the second surface, and the first hole segment is the hole segment closest to the first surface among the plurality of hole segments.

[0028] In the above technical solution, the first hole segment is the hole segment closest to the first surface among multiple hole segments. That is, the first hole segment is the hole segment closest to or furthest from the inside of the outer shell among multiple hole segments. During processing and manufacturing, the hole segments with larger cross-sectional areas can be processed first, and the first hole segment can be processed last. In this way, the first hole segment has higher precision, which is conducive to accurately controlling the burst pressure.

[0029] As an optional technical solution in this application embodiment, the first surface faces the interior of the outer shell.

[0030] In the above technical solution, when the first surface faces the inside of the outer casing, the first hole segment is the hole segment closest to the inside of the outer casing among multiple hole segments. At this time, the pressure relief mechanism is more likely to deform due to the change in air pressure inside the battery cell. Therefore, setting a first gap between the pressure relief mechanism and the first step surface has a better effect and is more conducive to improving the reliability of the battery cell.

[0031] As an optional technical solution in this application embodiment, the hole wall surface of the first hole segment is connected to the first step surface through a chamfered surface.

[0032] In the above technical solution, the hole wall surface and the first step surface of the first hole section are transitioned by a chamfer, making the transition between the hole wall surface and the first step surface of the first hole section smooth. When the pressure relief mechanism deforms due to the change in gas pressure inside the battery cell, even if the pressure relief mechanism collides with the chamfered surface, the stress on the pressure relief mechanism is smaller because the chamfered surface is not as sharp, which makes it less likely for the pressure relief mechanism to open the valve prematurely, thus improving the reliability of the battery cell.

[0033] As an optional technical solution in this application embodiment, the chamfered surface extends circumferentially along the first hole segment, the cross-section of the chamfered surface is arc-shaped, and the cross-section is perpendicular to the extension direction of the chamfered surface.

[0034] In the above technical solution, the hole wall surface and the first step surface of the first hole section are transitioned by rounded corners, making the transition between the hole wall surface and the first step surface of the first hole section smoother. When the pressure relief mechanism deforms due to the change in air pressure inside the battery cell, even if the pressure relief mechanism collides with the chamfered surface, the stress on the pressure relief mechanism is smaller because the chamfered surface is not as sharp, which makes it less likely for the pressure relief mechanism to open the valve prematurely, thus improving the reliability of the battery cell.

[0035] As an optional technical solution in this application embodiment, the radius of the arc is R, which satisfies: 0.2mm≤R≤1mm.

[0036] In the above technical solutions, when R ≥ 0.2 mm, the radius of the arc is relatively large. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is more likely to collide with the chamfered surface rather than with other parts, making it less likely for the pressure relief mechanism to open the valve prematurely, which helps improve the reliability of the battery cell. When R ≤ 1 mm, the radius of the arc is not too large. On the one hand, this prevents the depth of the first hole section from being too large, which helps reduce space occupation and allows the battery cell to have a higher energy density. On the other hand, it facilitates manufacturing. When 0.2 mm ≤ R ≤ 1 mm, both the reliability and energy density of the battery cell can be balanced, and manufacturing is also convenient.

[0037] As an optional technical solution in this application embodiment, the chamfered surface extends circumferentially along the first hole segment, the cross-section of the chamfered surface is linear, and the cross-section is perpendicular to the extension direction of the chamfered surface.

[0038] In the above technical solution, the hole wall surface and the first step surface of the first hole section are transitioned by an oblique angle, making the transition between the hole wall surface and the first step surface of the first hole section smoother. When the pressure relief mechanism deforms due to the change in gas pressure inside the battery cell, even if the pressure relief mechanism collides with the chamfered surface, the stress on the pressure relief mechanism is smaller because the chamfered surface is not as sharp, which makes it less likely for the pressure relief mechanism to open the valve prematurely, thus improving the reliability of the battery cell.

[0039] As an optional technical solution in this application embodiment, along the first direction, the minimum distance from the connection position of the chamfered surface and the first step surface to the hole wall of the pressure relief hole is L1, satisfying: 0.2mm≤L1≤1mm, and the first direction is perpendicular to the thickness direction of the wall portion; along the thickness direction of the wall portion, the minimum distance from the connection position of the chamfered surface and the hole wall of the first hole segment to the first step surface is L2, 0.2mm≤L2≤1mm.

[0040] In the above technical solutions, when L1≥0.2mm and L2≥0.2mm, the chamfered surface area is relatively large. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is more likely to collide with the chamfered surface than with other parts, making it less likely for the pressure relief mechanism to open the valve prematurely, which helps improve the reliability of the battery cell. When L1≤1mm and L2≤1mm, the chamfered surface area is not too large. On the one hand, this prevents the depth of the first hole section from being too large, which helps reduce space occupation and allows the battery cell to have a higher energy density. On the other hand, it facilitates manufacturing. When 0.2mm≤L1≤1mm and 0.2mm≤L2≤1mm, both the reliability and energy density of the battery cell can be balanced, and manufacturing is also convenient.

[0041] As an optional technical solution in this application embodiment, the outer peripheral surface of the pressure relief mechanism is welded to the hole wall surface of the second hole section.

[0042] In the above technical solution, by welding the outer peripheral surface of the pressure relief mechanism to the hole wall of the second hole section, the pressure relief mechanism and the wall are connected by a butt weld. Butt welds require less heat, making the pressure relief mechanism and the wall less prone to deformation during welding, thus improving weld quality. Furthermore, when welding the outer peripheral surface of the pressure relief mechanism to the hole wall of the second hole section, matching the shape and size of the outer peripheral surface of the pressure relief mechanism with the shape and size of the second hole section is sufficient to achieve high weld quality. Matching the shape and size of the outer peripheral surface of the pressure relief mechanism with the shape and size of the second hole section is relatively simple; therefore, welding the outer peripheral surface of the pressure relief mechanism to the hole wall of the second hole section is beneficial for improving weld quality.

[0043] As an optional technical solution in this application embodiment, the wall portion has a third surface, and the end of the second hole segment away from the first hole segment extends to the third surface, and the hole wall surface of the second hole segment is connected to the third surface; along the thickness direction of the wall portion, the pressure relief mechanism has a fourth surface away from the first hole segment, and the distance between the third surface and the fourth surface is H3, satisfying: 0≤H3≤0.3mm.

[0044] In the above technical solution, when 0≤H3≤0.3mm, the distance between the third surface and the fourth surface along the thickness direction of the wall is small, which is beneficial to improving the quality of the butt weld.

[0045] As an optional technical solution in this application embodiment, the wall portion has a third surface, one end of the second hole segment away from the first hole segment extends to the third surface, and the hole wall surface of the second hole segment is connected to the third surface; the pressure relief mechanism extends beyond the third surface in the direction from the first hole segment to the second hole segment, and the outer peripheral surface of the pressure relief mechanism is welded to the third surface.

[0046] In the above technical solution, by welding the outer peripheral surface of the pressure relief mechanism to the third surface, the pressure relief mechanism and the wall are connected by fillet weld, thereby achieving the welded connection between the pressure relief mechanism and the wall. This structure can achieve a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the pressure relief mechanism and the wall, thus effectively improving the connection stability between the pressure relief mechanism and the wall.

[0047] As an optional technical solution in this application embodiment, along the thickness direction of the wall portion, the pressure relief mechanism has a fourth surface facing away from the first hole segment, and the distance between the third surface and the fourth surface is H3, satisfying: H3 > 0.3 mm.

[0048] In the above technical solution, when H3 > 0.3mm, the distance between the third surface and the fourth surface along the thickness direction of the wall is relatively large, which is beneficial to improving the quality of the fillet weld.

[0049] As an optional technical solution in this application embodiment, the wall portion has a third surface, one end of the second hole segment away from the first hole segment extends to the third surface, and the hole wall surface of the second hole segment is connected to the third surface; along the thickness direction of the wall portion, the pressure relief mechanism includes a connecting portion disposed opposite to the third surface, and the connecting portion is welded to the third surface.

[0050] In the above technical solution, the pressure relief mechanism includes a connecting part disposed opposite to the third surface, and the connecting part is welded to the third surface. When welding the connecting part to the third surface, penetration welding can be used. The wall thickness in the area where the third surface is located is relatively large, so it is not easy to weld through the wall during welding. The welding effect between the connecting part and the wall is better, which is conducive to improving the connection stability between the pressure relief mechanism and the wall.

[0051] As an optional technical solution in this application embodiment, the base material of the pressure relief mechanism is aluminum, and the thickness of the pressure relief mechanism along the thickness direction of the wall is H4, satisfying: 0.2mm≤H4≤0.8mm, optionally, 0.3mm≤H4≤0.6mm.

[0052] In the above technical solution, since aluminum has low strength, when the base material of the pressure relief mechanism is aluminum, the thickness of the pressure relief mechanism can be increased to obtain higher strength. When the base material of the pressure relief mechanism is aluminum and H4 ≥ 0.2 mm, the pressure relief mechanism has a larger thickness and higher strength. The deformation of the pressure relief mechanism due to changes in gas pressure inside the battery cell is smaller, making it less likely for the pressure relief mechanism to collide with the connection position between the hole wall and the first step surface of the first hole section, and less likely to cause premature valve opening, which is beneficial to improving the reliability of the battery cell. When the base material of the pressure relief mechanism is aluminum and H4 ≤ 0.8 mm, the thickness of the pressure relief mechanism is not too large, which helps to reduce the space occupied and improve the energy density of the battery cell. Therefore, when the base material of the pressure relief mechanism is aluminum and 0.2 mm ≤ H4 ≤ 0.8 mm, both the reliability and energy density of the battery cell can be balanced.

[0053] When the base material of the pressure relief mechanism is aluminum, and H4 ≥ 0.3 mm, the mechanism has a greater thickness, resulting in higher strength. The deformation caused by pressure changes within the battery cell is also smaller, making it less prone to colliding with the connection between the hole wall and the first step surface of the first hole section. This reduces the likelihood of premature valve opening and improves the reliability of the battery cell. When the base material is aluminum, and H4 ≤ 0.6 mm, the thickness is not excessive, reducing space requirements and improving the energy density of the battery cell. Therefore, when the base material of the pressure relief mechanism is aluminum, and 0.3 mm ≤ H4 ≤ 0.6 mm, both battery cell reliability and energy density can be balanced.

[0054] As an optional technical solution in this application embodiment, the base material of the pressure relief mechanism is iron, and the thickness of the pressure relief mechanism along the thickness direction of the wall is H4, satisfying: 0.1mm≤H4≤0.4mm, optionally, 0.15mm≤H4≤0.3mm.

[0055] In the above technical solutions, due to the high strength of iron, using iron as the base material for the pressure relief mechanism results in higher strength, allowing for a reduction in the mechanism's thickness. When the base material is iron and H4 ≥ 0.1 mm, the pressure relief mechanism has a larger thickness and higher strength. This results in less deformation due to pressure changes within the battery cell, making it less likely to collide with the connection between the hole wall and the first step surface of the first hole section, thus reducing the risk of premature valve opening and improving battery cell reliability. When the base material is iron and H4 ≤ 0.4 mm, the thickness is not excessive, reducing space requirements and improving battery cell energy density. Therefore, using iron as the base material and having 0.1 mm ≤ H4 ≤ 0.4 mm balances battery cell reliability and energy density.

[0056] When the base material of the pressure relief mechanism is iron, and H4 ≥ 0.15mm, the mechanism has a greater thickness, resulting in higher strength. The deformation caused by pressure changes within the battery cell is also smaller, making it less prone to colliding with the connection between the hole wall and the first step surface of the first hole section, and less likely to cause premature valve opening, thus improving the reliability of the battery cell. When the base material is iron, and H4 ≤ 0.3mm, the thickness of the mechanism is not excessive, reducing space occupation and improving the energy density of the battery cell. Therefore, when the base material of the pressure relief mechanism is iron, and 0.15mm ≤ H4 ≤ 0.3mm, both battery cell reliability and energy density can be balanced.

[0057] As an optional technical solution in this application embodiment, the size of the second hole segment along the thickness direction of the wall is H5, satisfying: 0.25mm≤H5≤1.5mm, and optionally, 0.3mm≤H5≤1mm.

[0058] In the above technical solution, when H5 ≥ 0.25 mm, the second hole segment has a larger dimension along the thickness direction of the wall. On the one hand, this allows for a larger capacity to accommodate the pressure relief mechanism, reducing the length of the pressure relief mechanism extending out of the second hole segment in the direction away from the first hole segment. This helps reduce the risk of interference between other components and the pressure relief mechanism, thus improving the reliability of the battery cell. Furthermore, it allows for a larger dimension of the first gap along the thickness direction of the wall, and a greater distance between the pressure relief mechanism and the first step surface. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to collide with the connection point between the hole wall of the first hole segment and the first step surface, reducing the likelihood of premature valve opening and improving the reliability of the battery cell. On the other hand, when welding the pressure relief mechanism to the hole wall of the second hole segment, the larger dimension of the hole wall along the thickness direction of the wall makes welding easier and improves welding quality. When H5 ≤ 1.5 mm, the dimension of the second hole segment along the thickness direction of the wall is not excessive, which helps reduce space occupation and increase the energy density of the battery cell. Therefore, when 0.25mm≤H5≤1.5mm, both the reliability and energy density of the battery cell can be balanced.

[0059] When H5 ≥ 0.3 mm, the second hole segment has a larger dimension along the thickness direction of the wall. On the one hand, this allows for a larger capacity to accommodate the pressure relief mechanism, reducing the length of the pressure relief mechanism extending out of the second hole segment away from the first hole segment. This helps reduce the risk of interference between other components and the pressure relief mechanism, thus improving the reliability of the battery cell. Furthermore, it allows for a larger dimension of the first gap along the thickness direction of the wall, further distancing the pressure relief mechanism from the first step surface. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, it is less likely to collide with the connection point between the hole wall and the first step surface of the first hole segment, reducing the likelihood of premature valve opening and further improving the reliability of the battery cell. On the other hand, when welding the pressure relief mechanism to the hole wall of the second hole segment, the larger dimension of the hole wall along the thickness direction of the wall makes welding easier and improves welding quality. When H5 ≤ 1 mm, the dimension of the second hole segment along the thickness direction of the wall is not excessive, which helps reduce space occupation and increase the energy density of the battery cell. Therefore, when 0.3mm≤H5≤1mm, both the reliability and energy density of the battery cell can be balanced.

[0060] As an optional technical solution in this application embodiment, the size of the first hole segment along the thickness direction of the wall is H6, satisfying: 0.2mm≤H6≤2mm, and optionally, 0.3mm≤H6≤1.5mm.

[0061] In the above technical solution, when H6 ≥ 0.2 mm, the dimension of the first hole segment along the thickness direction of the wall is relatively large, and the thickness of the wall in the area where the first step surface is located is also relatively large. This allows the first step surface to better support the pressure relief mechanism. When laser welding is used to weld the pressure relief mechanism and the wall, the first step surface can effectively block the laser, making it less likely for the laser to penetrate the wall, which is beneficial to improving the reliability of the battery cell. When H6 ≤ 2 mm, the dimension of the first hole segment along the thickness direction of the wall is not too large, which helps to reduce space occupation and improve the energy density of the battery cell. Therefore, when 0.2 mm ≤ H6 ≤ 2 mm, both the reliability and energy density of the battery cell can be balanced.

[0062] When H6 ≥ 0.3 mm, the dimension of the first hole segment along the thickness direction of the wall is larger, and the wall thickness in the region where the first step surface is located is also larger. This allows the first step surface to better support the pressure relief mechanism. When laser welding the pressure relief mechanism and the wall, the first step surface can better shield the laser, making it less likely for the laser to penetrate the wall, which is beneficial to improving the reliability of the battery cell. When H6 ≤ 1.5 mm, the dimension of the first hole segment along the thickness direction of the wall is not too large, which helps to reduce space occupation and improve the energy density of the battery cell. Therefore, when 0.3 mm ≤ H6 ≤ 1.5 mm, it is possible to better balance the reliability and energy density of the battery cell.

[0063] As an optional technical solution in this application embodiment, the pressure relief mechanism is provided with a first groove, and the pressure relief mechanism is configured to crack along at least a portion of the first groove when the pressure inside the housing reaches a threshold, so as to release the pressure, wherein the first groove is projected into the first hole segment along the thickness direction of the wall portion.

[0064] In the above technical solution, the pressure relief mechanism is relatively weak at the location of the first groove. When the battery cell depressurizes, the pressure relief mechanism can split at least part of the first groove, allowing it to open and release pressure. By positioning the projection of the first groove along the thickness direction of the wall within the first hole segment, i.e., the cross-sectional area of ​​the first hole segment is larger than the area of ​​the pressure relief zone defined by the first groove (the pressure relief zone opens when the battery cell depressurizes, forming an opening for the fluid medium to pass through), the fluid medium inside the casing can quickly pass through the first hole segment and act on the pressure relief mechanism when the battery cell depressurizes, causing the pressure relief mechanism to open and release pressure quickly, which helps improve the timeliness of pressure relief for the battery cell. In addition, when the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, the pressure relief zone is less likely to collide with the connection between the hole wall surface and the first step surface of the first hole segment, making it less likely for the pressure relief mechanism to open prematurely, which helps improve the reliability of the battery cell.

[0065] As an optional technical solution in this application embodiment, along the first direction, the minimum distance between the hole wall surface of the first hole segment and the first groove is L3, which satisfies: 1mm≤L3≤3mm, and the first direction is perpendicular to the thickness direction of the wall portion.

[0066] In the above technical solution, when L3 ≥ 1mm, the minimum distance between the hole wall of the first hole segment and the first groove along the first direction is relatively large. When the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, the pressure relief area is less likely to collide with the connection position between the hole wall of the first hole segment and the first step surface, thus preventing premature valve opening by the pressure relief mechanism and improving the reliability of the battery cell. When L3 ≤ 3mm, the minimum distance between the hole wall of the first hole segment and the first groove along the first direction is not too large, resulting in a larger area of ​​the pressure relief area, which is beneficial for rapid pressure relief of the battery cell and improves its reliability. Therefore, when 1mm ≤ L3 ≤ 3mm, it is beneficial to improve the reliability of the battery cell.

[0067] As an optional technical solution in this application embodiment, the pressure relief mechanism is provided with a second groove, and the first groove is provided on the bottom surface of the second groove.

[0068] In the above technical solution, the opening of the first groove is formed on the bottom surface of the second groove. During manufacturing, the second groove can be formed first, and then the first groove can be formed, thereby reducing the forming force on the pressure relief mechanism, reducing the risk of cracks in the pressure relief mechanism, and improving the reliability of the battery cell.

[0069] As an optional technical solution in this application embodiment, the second groove is projected along the thickness direction of the wall portion and located within the first hole segment.

[0070] In the above technical solution, the projection of the second groove along the thickness direction of the wall is located within the first hole section. When the pressure relief mechanism deforms due to the change in air pressure inside the battery cell, the bottom wall of the second groove is less likely to collide with the connection position of the hole wall surface and the first step surface of the first hole section. The area outside the second groove where the pressure relief mechanism is located has a larger thickness. Even if the area outside the second groove where the pressure relief mechanism is located collides with the connection position of the hole wall surface and the first step surface of the first hole section, it is less likely to cause the pressure relief mechanism to open the valve prematurely, which is beneficial to improving the reliability of the battery cell.

[0071] As an optional technical solution in this application embodiment, along the first direction, the minimum distance between the hole wall surface of the first hole segment and the groove side surface of the second groove is L4, satisfying: 0≤L4≤2mm, and optionally, 0.3mm≤L4≤1mm.

[0072] In the above technical solution, when L4≥0, when the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, the bottom wall of the second groove is less likely to collide with the connection position between the hole wall and the first step surface of the first hole section. The area outside the second groove of the pressure relief mechanism has a greater thickness. Even if the area outside the second groove of the pressure relief mechanism collides with the connection position between the hole wall and the first step surface of the first hole section, it is less likely to cause premature valve opening, which is beneficial to improving the reliability of the battery cell. When L4≤2mm, the minimum distance between the hole wall of the first hole section along the first direction and the side surface of the second groove is not too large, which is beneficial to having a larger pressure relief area, facilitating rapid pressure relief of the battery cell and improving its reliability.

[0073] When L4 ≥ 0.3 mm, when the pressure relief mechanism deforms due to changes in the internal air pressure of the battery cell, the bottom wall of the second groove is less likely to collide with the connection point between the hole wall and the first step surface of the first hole section. The area outside the second groove of the pressure relief mechanism has a greater thickness. Even if the area outside the second groove of the pressure relief mechanism collides with the connection point between the hole wall and the first step surface of the first hole section, it is less likely to cause premature valve opening, which is beneficial to improving the reliability of the battery cell. When L4 ≤ 1 mm, the minimum distance between the hole wall of the first hole section along the first direction and the side of the second groove is not too large, which is beneficial to having a larger pressure relief area, facilitating rapid pressure relief of the battery cell and improving its reliability.

[0074] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned battery cell.

[0075] 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

[0076] 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.

[0077] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0078] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0079] Figure 3 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0080] Figure 4 is an exploded view of a battery cell provided in some embodiments of this application;

[0081] Figure 5 is a bottom view of the casing of a battery cell provided in some embodiments of this application;

[0082] Figure 6 is a cross-sectional view of position AA in Figure 5;

[0083] Figure 7 is a cross-sectional view of a battery cell provided in some other embodiments of this application;

[0084] Figure 8 is a cross-sectional view of a battery cell provided in some embodiments of this application;

[0085] Figure 9 is a cross-sectional view of a battery cell provided in some embodiments of this application;

[0086] Figure 10 is a cross-sectional view of a battery cell provided in some embodiments of this application;

[0087] Figure 11 is a cross-sectional view of a battery cell provided in some other embodiments of this application;

[0088] Figure 12 is a cross-sectional view of a battery cell provided in some other embodiments of this application;

[0089] Figure 13 is a cross-sectional view of a battery cell provided in some other embodiments of this application.

[0090] Icons: 10-Box body; 11-First box body; 12-Second box body; 20-Battery cell; 21-Outer shell; 211-Shell; 2111-Side wall; 212-End cap; 2112-Bottom wall; 213-Wall section; 2131-Pressure relief hole; 21311-First hole section; 21312-Second hole section; 21313-Third hole section; 21314-Fourth hole section; 2132-First stepped surface; 2133-First gap; 2134-Second gap; 2135-Flow channel; 213 6-Second step surface; 2137-First surface; 2138-Second surface; 2139-Chamfered surface; 214-Third surface; 22-Pressure relief mechanism; 221-First groove; 222-Second groove; 223-Connecting part; 224-Fourth surface; 225-Fifth surface; 23-Electrode assembly; 231-Main body; 232-Electrode tab; 24-Electrode terminal; 25-Insulator; 26-Protective part; 100-Battery device; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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 three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0096] 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.

[0097] In this application, "multiple" means two or more (including two).

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.).

[0104] 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 / 3 Mn 1 / 3 O2 (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 0.05At least one of O2 and its modified compounds.

[0105] 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.

[0106] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0107] 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.).

[0108] 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.

[0109] 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.

[0110] 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.

[0111] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0112] 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.

[0113] 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.

[0114] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0119] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0120] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0121] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0122] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0123] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0124] In some implementations, the electrode assembly is a stacked structure.

[0125] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0126] 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.

[0127] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0128] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0129] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0130] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0131] 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.

[0132] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0133] 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.

[0134] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch 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.

[0135] The battery apparatus 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.

[0136] 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.

[0137] As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0138] In some embodiments, the battery device may be a battery pack, which may include a housing and one or more individual battery cells housed within the housing.

[0139] 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.

[0140] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] The development of battery technology must consider multiple design factors simultaneously, such as performance parameters like energy density, cycle life, discharge capacity, and charge / discharge rate. Additionally, battery reliability must also be considered. However, current battery reliability is relatively poor.

[0147] To improve the reliability of individual battery cells, existing technologies include setting a pressure relief mechanism on the end cap of the battery cell. This mechanism has grooves that allow the pressure relief mechanism to crack along the grooves when the internal pressure of the battery cell reaches the burst pressure, thereby releasing the internal pressure of the battery cell and reducing the risk of explosion and fire.

[0148] In existing technology, to facilitate welding the pressure relief mechanism to the end cap, a pressure relief hole and a mounting groove are provided on the end cap. The pressure relief hole and the mounting groove are connected, and the wall surface of the pressure relief hole and the side surface of the mounting groove are connected by a stepped surface. In other words, the pressure relief hole and the mounting groove together form a stepped hole. The pressure relief mechanism is housed in the mounting groove and abuts against the stepped surface. However, during the use of the battery cell, the pressure relief mechanism will deform under the action of the gas inside the battery cell, constantly colliding with the connection point between the wall surface of the pressure relief hole and the stepped surface. This causes the pressure relief mechanism to open prematurely, resulting in poor reliability of the battery cell.

[0149] In view of this, this application provides a battery cell, which includes a casing and a pressure relief mechanism. The casing has a wall portion, and the wall portion is provided with a pressure relief hole, which penetrates the wall portion along its thickness direction. The pressure relief hole includes a plurality of hole segments arranged along the thickness direction of the wall portion, including adjacent first hole segments and second hole segments. The hole wall surfaces of the first hole segments and the second hole segments are connected by a first stepped surface. The cross-sectional area of ​​the second hole segment is larger than the cross-sectional area of ​​the first hole segment, and the cross-section is perpendicular to the thickness direction of the wall portion. The pressure relief mechanism is at least partially located within the second hole segment and is disposed facing the first stepped surface. The projection of the pressure relief mechanism along the thickness direction of the wall portion covers the first hole segment. A first gap exists between the pressure relief mechanism and the first stepped surface along the thickness direction of the wall portion.

[0150] By housing the pressure relief mechanism within the second bore section, the height of the mechanism protruding from the wall is reduced, lowering the risk of interference with other components and minimizing its space occupation, thus improving the energy density of the battery cell. Furthermore, the second bore section provides positioning for the pressure relief mechanism, simplifying assembly. Additionally, when the pressure relief mechanism is welded to the wall, the first step surface acts as a laser barrier, reducing the risk of laser damage to other components. Moreover, by creating a first gap between the pressure relief mechanism and the first step surface, when the mechanism deforms due to pressure changes within the battery cell, it is less likely to collide with the connection point between the bore wall and the first step surface, preventing premature valve opening and improving the reliability of the battery cell.

[0151] 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.

[0152] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0153] Please refer to Figure 1, which is a structural schematic diagram 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.

[0154] 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.

[0155] 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.

[0156] Please refer to Figure 2, which 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, with the housing 10 used to house the battery cells 20.

[0157] 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 space.

[0158] 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.

[0159] 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.

[0160] Please refer to Figures 3, 4, 5, and 6. Figure 3 is a structural schematic diagram of a battery cell 20 provided in some embodiments of this application. Figure 4 is an exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 is a bottom view of the outer casing 21 of the battery cell 20 provided in some embodiments of this application. Figure 6 is a cross-sectional view at position AA in Figure 5. This application provides a battery cell 20, which includes an outer casing 21 and a pressure relief mechanism 22. The outer casing 21 has a wall portion 213, and the wall portion 213 is provided with a pressure relief hole 2131, which penetrates the wall portion 213 along its thickness direction. The pressure relief hole 2131 includes multiple hole segments arranged along the thickness direction of the wall portion 213. These segments include adjacent first hole segments 21311 and second hole segments 21312. The hole wall surfaces of the first hole segment 21311 and the second hole segment 21312 are connected by a first stepped surface 2132. The cross-sectional area of ​​the second hole segment 21312 is larger than that of the first hole segment 21311, and the cross-section is perpendicular to the thickness direction of the wall portion 213. The pressure relief mechanism 22 is at least partially located within the second hole segment 21312 and faces the first stepped surface 2132. The projection of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 covers the first hole segment 21311. A first gap 2133 exists between the pressure relief mechanism 22 and the first stepped surface 2132 along the thickness direction of the wall portion 213.

[0161] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0162] The housing 21 may include a housing 211 and an end cap 212. The housing 211 has a receiving space with an opening at least at one end for accommodating the electrode assembly 23. The end cap 212 is connected to the housing 211 and closes the opening. Here, "closed" means covered or closed, and can be either sealed or unsealed.

[0163] End cap 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 212 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved reliability. The material of end cap 212 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic. End cap 212 is also provided with electrode terminals 24, which are used for electrical connection with the tabs 232 of electrode assembly 23 to input or output electrical energy of battery cell 20. Electrode terminals 24 and tabs 232 can be directly connected, for example, by direct welding of electrode terminals 24 to tabs 232. The electrode terminal 24 and the tab 232 can also be indirectly connected, for example, through a current collector. The battery cell 20 also includes an insulator 25 disposed inside the end cap 212. The insulator 25 can be used to isolate the electrical connection components within the housing 211 from the end cap 212 to reduce the risk of short circuits. For example, the insulator 25 can be made of plastic, rubber, etc.

[0164] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. An opening can be provided on the housing 211, and the end cap 212 can be used to close the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and the housing 211 can be integrated. Specifically, the end cap 212 and the housing 211 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 211, the end cap 212 closes the housing 211. The housing 211 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 211 can include, but is not limited to, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0165] In an embodiment where the housing 211 has an opening at one end, one end cap 212 may be provided. In an embodiment where the housing 211 has openings at both opposite ends, two end caps 212 may be provided. The two end caps 212 respectively close the two openings of the housing 211, and the two end caps 212 and the housing 211 together define the receiving space for accommodating the electrode assembly 23.

[0166] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The housing 211 may contain one or more electrode assemblies 23. The electrode assembly 23 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 231 of the electrode assembly 23, while the portions of the positive and negative electrode sheets without active material each constitute a tab 232. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body 231. During the charging and discharging process of the battery cell 20, the positive and negative active materials react with the electrolyte.

[0167] The wall portion 213 can be an end cap 212 of the outer casing 21, or it can be a wall of the housing 211 of the outer casing 21. Exemplarily, in Figures 3, 4, and 5, the wall portion 213 is the bottom wall 2112 of the housing 211, which is disposed opposite to the end cap 212. In other embodiments, the wall portion 213 is the end cap 212. In still other embodiments, the wall portion 213 can also be a side wall 2111 of the housing 211 that is adjacent to and connected to the end cap 212.

[0168] The pressure relief mechanism 22 is a component used to open when the internal pressure or temperature of the battery cell 20 reaches the burst pressure, thereby releasing the internal pressure of the battery cell 20. The pressure relief mechanism 22 is a component mounted on the wall portion 213, and is separately provided and connected to the wall portion 213. During manufacturing, the pressure relief mechanism 22 and the wall portion 213 are provided separately and ultimately connected together; for example, the pressure relief mechanism 22 can be welded to the wall portion 213. The pressure relief mechanism 22 can be a burst-proof plate mounted on the wall portion 213. The location of the pressure relief mechanism 22 can be used to determine which wall of the housing 21 is the wall portion 213. For example, when the pressure relief mechanism 22 is located on the end cap 212, then the end cap 212 is the wall portion 213. When the pressure relief mechanism 22 is located on the bottom wall 2112 of the housing 211, then the bottom wall 2112 is the wall portion 213. When the pressure relief mechanism 22 is provided on one side wall 2111 of the housing 211, the side wall 2111 is the wall portion 213.

[0169] Please refer to Figures 3, 4, 5 and 6. The thickness direction of the wall portion 213 is the X direction shown in the figures.

[0170] A pressure relief hole 2131 is provided on the wall portion 213. The pressure relief hole 2131 is a through hole that penetrates two opposing surfaces of the wall portion 213 along the thickness direction of the wall portion 213. The pressure relief hole 2131 may include two, three, four, or more hole segments. The multiple hole segments are arranged along the thickness direction of the wall portion 213, and the cross-sectional areas of two adjacent hole segments perpendicular to the thickness direction of the wall portion 213 are different.

[0171] The first hole segment 21311 and the second hole segment 21312 are two adjacent hole segments among a plurality of hole segments. The cross-sectional area of ​​the first hole segment 21311 perpendicular to the thickness direction of the wall portion 213 is smaller than the cross-sectional area of ​​the second hole segment 21312 perpendicular to the thickness direction of the wall portion 213. When both the first hole segment 21311 and the second hole segment 21312 are circular holes, the diameter of the first hole segment 21311 is smaller than the diameter of the second hole segment 21312.

[0172] Referring to Figure 6, in some embodiments, a portion of the pressure relief mechanism 22 is housed within the second hole segment 21312, while another portion is located outside the second hole segment 21312. Referring to Figure 7, which is a cross-sectional view of the battery cell 20 provided in other embodiments of this application, in other embodiments, the pressure relief mechanism 22 is completely housed within the second hole segment 21312. Along the thickness direction of the wall portion 213, a portion of the pressure relief mechanism 22 is disposed opposite to the first step surface 2132. The projection of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 covers the first hole segment 21311; in other words, the projection of the hole wall surface of the first hole segment 21311 along the thickness direction of the wall portion 213 is completely located within the pressure relief mechanism 22, and the pressure relief mechanism 22 obstructs the first hole segment 21311.

[0173] The first stepped surface 2132 connects the hole wall of the first hole segment 21311 and the hole wall of the second hole segment 21312. Along the thickness direction of the wall portion 213, there is a first gap 2133 between the pressure relief mechanism 22 and the first stepped surface 2132. In other words, the pressure relief mechanism 22 is spaced apart from the first stepped surface 2132 along the thickness direction of the wall portion 213.

[0174] By accommodating the pressure relief mechanism 22 within the second bore section 21312, on the one hand, the height of the pressure relief mechanism 22 protruding from the wall portion 213 can be reduced, lowering the risk of interference between the pressure relief mechanism 22 and other components, and reducing the space occupied by the pressure relief mechanism 22, which is beneficial to improving the energy density of the battery cell 20. On the other hand, the second bore section 21312 can position the pressure relief mechanism 22, which is beneficial to simplifying assembly. In addition, when the pressure relief mechanism 22 is connected to the wall portion 213 by welding, the first step surface 2132 can block the laser, thereby reducing the risk of laser damage to other components. Furthermore, by creating a first gap 2133 between the pressure relief mechanism 22 and the first step surface 2132, when the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, the pressure relief mechanism 22 is less likely to collide with the connection position of the bore wall of the first bore section 21311 and the first step surface 2132, which is less likely to cause the pressure relief mechanism 22 to open prematurely, thus improving the reliability of the battery cell 20.

[0175] Please refer to Figures 3, 4, 5, 6 and 7. In some embodiments, the size of the first gap 2133 along the thickness direction of the wall 213 is H1, which satisfies: 0.05mm≤H1≤1mm.

[0176] H1 represents the dimension of the first gap 2133 along the thickness direction of the wall portion 213. The dimension of the first gap 2133 along the thickness direction of the wall portion 213 can be uniform or variable. In this case, the minimum dimension of the first gap 2133 along the thickness direction of the wall portion 213 is greater than or equal to 0.05 mm, and the maximum dimension of the first gap 2133 along the thickness direction of the wall portion 213 is less than or equal to 1 mm. During measurement, multiple measurements can be taken, and the average value can be used as H1.

[0177] The dimensions of the first gap 2133 along the thickness direction of the wall portion 213 can be: H1 = 0.05mm, 0.08mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0178] When H1 ≥ 0.05 mm, the dimension of the first gap 2133 along the thickness direction of the wall 213 is relatively large, and the pressure relief mechanism 22 is far from the first step surface 2132. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely to collide with the connection position between the hole wall of the first hole section 21311 and the first step surface 2132, thus preventing premature opening of the valve and improving the reliability of the battery cell 20. When H1 ≤ 1 mm, the dimension of the first gap 2133 along the thickness direction of the wall 213 is not too large, which helps to reduce space occupation and improve the energy density of the battery cell 20. Therefore, when 0.05 mm ≤ H1 ≤ 1 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0179] Optionally, 0.1mm ≤ H1 ≤ 0.5mm.

[0180] The dimensions of the first gap 2133 along the thickness direction of the wall portion 213 can be: H1 = 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc.

[0181] When H1 ≥ 0.1 mm, the dimension of the first gap 2133 along the thickness direction of the wall 213 is larger, and the pressure relief mechanism 22 is farther away from the first step surface 2132. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely to collide with the connection position between the hole wall of the first hole section 21311 and the first step surface 2132, and it is less likely to cause the pressure relief mechanism 22 to open prematurely, which is more conducive to improving the reliability of the battery cell 20. When H1 ≤ 0.5 mm, the dimension of the first gap 2133 along the thickness direction of the wall 213 is not too large, which helps to reduce space occupation and improve the energy density of the battery cell 20. Therefore, when 0.1 mm ≤ H1 ≤ 0.5 mm, it is better to balance the reliability and energy density of the battery cell 20.

[0182] Please refer to Figure 8, which is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. In some embodiments, the battery cell 20 includes a protective member 26, which is disposed on the wall portion 213 and located on the side of the pressure relief mechanism 22 opposite to the first hole segment 21311. Along the thickness direction of the wall portion 213, the projection of the protective member 26 covers the pressure relief mechanism 22, and a second gap 2134 exists between the pressure relief mechanism 22 and the protective member 26.

[0183] The protective component 26 is used to shield the pressure relief mechanism 22. The protective component 26 reduces the risk of external forces acting on the side of the pressure relief mechanism 22 away from the first orifice section 21311, making it less likely for the pressure relief mechanism 22 to open prematurely. The protective component 26 also blocks impurities, preventing them from falling onto the pressure relief mechanism 22 and affecting its normal valve opening. The protective component 26 is located on the side of the pressure relief mechanism 22 away from the first orifice section 21311 and is connected to the wall portion 213. In other words, along the thickness direction of the wall portion 213, the protective component 26 and the first orifice section 21311 are located on opposite sides of the pressure relief mechanism 22. The projection of the protective component 26 along the thickness direction of the wall portion 213 covers the pressure relief mechanism 22; in other words, the projection of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 falls entirely within the protective component 26.

[0184] The protective element 26 may be made of an insulating material, such as plastic, rubber, etc. In some embodiments, the protective element 26 may be adhered to the wall portion 213.

[0185] The pressure relief mechanism 22 has a second gap 2134 between it and the protective member 26 along the thickness direction of the wall portion 213, that is, the pressure relief mechanism 22 is provided with a gap between it and the protective member 26 along the thickness direction of the wall portion 213.

[0186] By incorporating the protective element 26, on the one hand, the risk of external forces acting on the side of the pressure relief mechanism 22 away from the first hole section 21311 can be reduced, making it less likely for the pressure relief mechanism 22 to open prematurely, which is beneficial to improving the reliability of the battery cell 20. On the other hand, the protective element 26 can shield impurities, preventing them from falling onto the pressure relief mechanism 22 and affecting its normal valve opening, which is beneficial to improving the reliability of the battery cell 20. In addition, by setting a second gap 2134 between the pressure relief mechanism 22 and the protective element 26, when the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely for the pressure relief mechanism 22 to interfere with the protective element 26. When the battery cell 20 is depressurized, it also helps the pressure relief mechanism 22 to open a larger opening, thereby allowing the battery cell 20 to depressurize quickly, which is beneficial to improving the reliability of the battery cell 20.

[0187] Referring to Figure 8, in some embodiments, the size of the second gap 2134 along the thickness direction of the wall portion 213 is H2, satisfying: 0.05mm≤H2≤0.3mm.

[0188] H2 represents the dimension of the second gap 2134 along the thickness direction of the wall portion 213. The dimension of the second gap 2134 along the thickness direction of the wall portion 213 can be uniform or variable. In this case, the minimum dimension of the second gap 2134 along the thickness direction of the wall portion 213 is greater than or equal to 0.05 mm, and the maximum dimension of the second gap 2134 along the thickness direction of the wall portion 213 is less than or equal to 0.3 mm. During measurement, multiple measurements can be taken, and the average value can be used as H2.

[0189] The dimensions of the second gap 2134 along the thickness direction of the wall portion 213 can be: H2 = 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, etc.

[0190] When H2 ≥ 0.05 mm, the second gap 2134 has a larger dimension along the thickness direction of the wall 213, and the pressure relief mechanism 22 is farther from the protective component 26. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely to interfere with the protective component 26. During pressure relief of the battery cell 20, it also facilitates the opening of the pressure relief mechanism 22, allowing for rapid pressure relief and improving the reliability of the battery cell 20. When H2 ≤ 0.3 mm, the second gap 2134 is not too large along the thickness direction of the wall 213, which helps reduce space occupation and increase the energy density of the battery cell 20. Therefore, when 0.05 mm ≤ H2 ≤ 0.3 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0191] Optionally, 0.1mm ≤ H2 ≤ 0.25mm.

[0192] The dimension of the second gap 2134 along the thickness direction of the wall portion 213 can be: H2 = 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, etc.

[0193] When H2 ≥ 0.1 mm, the second gap 2134 has a larger dimension along the thickness direction of the wall 213, and the pressure relief mechanism 22 is farther away from the protective component 26. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely to interfere with the protective component 26. During pressure relief of the battery cell 20, it also allows the pressure relief mechanism 22 to open a larger opening, enabling rapid pressure relief of the battery cell 20 and improving its reliability. When H2 ≤ 0.25 mm, the second gap 2134 is not too large along the thickness direction of the wall 213, which helps reduce space occupation and increase the energy density of the battery cell 20. Therefore, when 0.1 mm ≤ H2 ≤ 0.25 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0194] Referring to Figure 8, in some embodiments, the plurality of hole segments include a third hole segment 21313 adjacent to the second hole segment 21312, the second hole segment 21312 connecting the first hole segment 21311 and the third hole segment 21313. The cross-sectional area of ​​the third hole segment 21313 is larger than the cross-sectional area of ​​the second hole segment 21312. A protective member 26 is disposed on the side of the third hole segment 21313 opposite to the second hole segment 21312 and covers the third hole segment 21313.

[0195] The third hole segment 21313 is the hole segment adjacent to the second hole segment 21312 among multiple hole segments. Along the thickness direction of the wall portion 213, the first hole segment 21311 and the third hole segment 21313 are located at the two ends of the second hole segment 21312, respectively. The second hole segment 21312 connects the first hole segment 21311 and the third hole segment 21313.

[0196] The cross-sectional area of ​​the third hole segment 21313 perpendicular to the thickness direction of the wall portion 213 is greater than the cross-sectional area of ​​the second hole segment 21312 perpendicular to the thickness direction of the wall portion 213. When both the third hole segment 21313 and the second hole segment 21312 are circular holes, the diameter of the third hole segment 21313 is greater than the diameter of the second hole segment 21312. The cross-sectional areas of the first hole segment 21311, the second hole segment 21312, and the third hole segment 21313 perpendicular to the thickness direction of the wall portion 213 gradually increase.

[0197] The protective member 26 is disposed at the end of the third hole segment 21313 away from the second hole segment 21312, and the projection of the protective member 26 along the thickness direction of the wall portion 213 covers the third hole segment 21313.

[0198] By providing the third hole section 21313, on the one hand, the third hole section 21313 allows the protective member 26 to be moved away from the pressure relief mechanism 22, that is, at least a portion of the third hole section 21313 can serve as the second gap 2134. On the other hand, a portion of the pressure relief mechanism 22 can be accommodated in the third hole section 21313, which helps to reduce the depth requirement of the second hole section 21312, thereby facilitating processing and manufacturing.

[0199] Referring to Figure 8, in some embodiments, a portion of the pressure relief mechanism 22 is accommodated in the second orifice 21312, and another portion of the pressure relief mechanism 22 is accommodated in the third orifice 21313.

[0200] By accommodating a portion of the pressure relief mechanism 22 in the second hole section 21312 and another portion of the pressure relief mechanism 22 in the third hole section 21313, it is beneficial to reduce the depth requirement of the second hole section 21312, thereby facilitating processing and manufacturing.

[0201] Referring to Figure 8, in some embodiments, the wall portion 213 is provided with a flow channel 2135, which connects the third hole section 21313 and the outside of the outer casing 21.

[0202] The flow channel 2135 is a fluid channel connecting the third hole section 21313 and the outside of the outer casing 21. When the battery cell 20 is depressurized, the depressurization mechanism 22 is opened, and the fluid medium flows from the third hole section 21313 through the flow channel 2135 to the outside of the outer casing 21 after passing through the depressurization mechanism 22, so as to achieve depressurization.

[0203] In some embodiments, the flow channel 2135 is a hole or groove provided in the wall portion 213, one end of the flow channel 2135 extends to the hole wall surface of the third hole segment 21313, and the other end of the flow channel 2135 extends to the outside of the wall portion 213.

[0204] By setting the flow channel 2135, when the battery cell 20 is depressurized, the pressure relief mechanism 22 opens, and the fluid medium inside the battery cell 20 can be discharged to the outside of the outer casing 21 through the first orifice 21311, the pressure relief mechanism 22, the third orifice 21313 and the flow channel 2135, thereby achieving pressure relief.

[0205] Please refer to Figure 9, which is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. In some embodiments, the plurality of aperture segments include a fourth aperture segment 21314 adjacent to the third aperture segment 21313. The third aperture segment 21313 connects the second aperture segment 21312 and the fourth aperture segment 21314. The cross-sectional area of ​​the fourth aperture segment 21314 is larger than the cross-sectional area of ​​the third aperture segment 21313. The protective member 26 is at least partially accommodated in the fourth aperture segment 21314.

[0206] The fourth hole segment 21314 is the hole segment adjacent to the third hole segment 21313 among multiple hole segments. Along the thickness direction of the wall portion 213, the second hole segment 21312 and the fourth hole segment 21314 are located at both ends of the third hole segment 21313, and the third hole segment 21313 connects the second hole segment 21312 and the fourth hole segment 21314.

[0207] The cross-sectional area of ​​the fourth hole segment 21314 perpendicular to the thickness direction of the wall portion 213 is greater than the cross-sectional area of ​​the third hole segment 21313 perpendicular to the thickness direction of the wall portion 213. When both the third hole segment 21313 and the fourth hole segment 21314 are circular holes, the diameter of the fourth hole segment 21314 is greater than the diameter of the third hole segment 21313. The cross-sectional areas of the first hole segment 21311, the second hole segment 21312, the third hole segment 21313, and the fourth hole segment 21314 perpendicular to the thickness direction of the wall portion 213 gradually increase.

[0208] The protective element 26 can be partially housed within the fourth hole section 21314, with the other part located outside the fourth hole section 21314. Alternatively, the protective element 26 can be completely housed within the fourth hole section 21314.

[0209] By having the protective member 26 at least partially accommodated within the fourth hole segment 21314, it is beneficial to reduce the height of the protective member 26 protruding from the surface of the wall portion 213 away from the interior of the outer casing 21. On the one hand, this helps to reduce the volume occupied by the protective member 26 in the battery device 100, which is beneficial to improving the energy density of the battery device 100. On the other hand, it helps to reduce the risk of interference between the protective member 26 and other components. In addition, the fourth hole segment 21314 can, to a certain extent, position the protective member 26, thereby facilitating quick installation of the protective member 26.

[0210] Referring to Figure 9, in some embodiments, the protective member 26 is completely accommodated within the fourth hole segment 21314.

[0211] When the protective member 26 is fully contained within the fourth hole segment 21314, the surface of the protective member 26 facing away from the third hole segment 21313 can be flush with the end of the fourth hole segment 21314 facing away from the third hole segment 21313, and the surface of the protective member 26 facing away from the third hole segment 21313 can also be closer to the third hole segment 21313 than the end of the fourth hole segment 21314 facing away from the third hole segment 21313.

[0212] In some embodiments, the wall portion 213 includes a second surface 2138, which is the surface of the wall portion 213 furthest from the interior of the housing 21. A fourth hole segment 21314 is disposed on the second surface 2138. In this case, the surface of the protective member 26 facing away from the third hole segment 21313 can be flush with the second surface 2138, and the surface of the protective member 26 facing away from the third hole segment 21313 can also be closer to the third hole segment 21313 than the second surface 2138.

[0213] By completely housing the protective element 26 within the fourth hole segment 21314, it is beneficial to reduce the volume occupied by the protective element 26 on the battery device 100, thereby improving the energy density of the battery device 100. On the other hand, it is beneficial to reduce the risk of interference between the protective element 26 and other components.

[0214] Referring to Figure 9, in some embodiments, the hole wall surface of the third hole segment 21313 and the hole wall surface of the fourth hole segment 21314 are connected by the second step surface 2136, and the protective member 26 abuts against the second step surface 2136.

[0215] The second step surface 2136 connects the hole wall surface of the third hole segment 21313 and the hole wall surface of the fourth hole segment 21314. The protective member 26 can directly abut against the second step surface 2136, or it can indirectly abut against the second step surface 2136. For example, the protective member 26 can be bonded to the second step surface 2136.

[0216] The flow channel 2135 can be a groove provided on the second step surface 2136. One end of the flow channel 2135 extends to the hole wall of the third hole section 21313. The protective member 26 covers a part of the flow channel 2135, and the other part of the flow channel 2135 is exposed.

[0217] By placing the protective element 26 against the second step surface 2136, on the one hand, it simplifies the installation of the protective element 26 and better fixes the relative position of the protective element 26 and the pressure relief mechanism 22. On the other hand, it makes it more difficult for external impurities to enter the third hole section 21313, making it less likely for impurities to fall onto the pressure relief mechanism 22 and less likely to affect the normal opening of the pressure relief mechanism 22, which is beneficial to improving the reliability of the battery cell 20.

[0218] Referring to Figure 9, in some embodiments, along the thickness direction of the wall portion 213, the wall portion 213 has opposing first surfaces 2137 and second surfaces 2138, and the pressure relief hole 2131 penetrates through the first surface 2137 and the second surface 2138. The first hole segment 21311 is the hole segment closest to the first surface 2137 among a plurality of hole segments.

[0219] Along the thickness direction of the wall portion 213, one of the first surface 2137 and the second surface 2138 is the surface of the wall portion 213 closest to the interior of the outer casing 21, and the other of the first surface 2137 and the second surface 2138 is the surface of the wall portion 213 furthest from the interior of the outer casing 21. The first surface 2137 is disposed opposite to the second surface 2138 along the thickness direction of the wall portion 213. One end of the pressure relief hole 2131 extends to the first surface 2137, and the other end of the pressure relief hole 2131 extends to the second surface 2138.

[0220] The first hole segment 21311 extends to the first surface 2137, that is, the first hole segment 21311 is the hole segment that is closest to or furthest from the interior of the outer casing 21 among the multiple hole segments.

[0221] The first hole segment 21311 is the hole segment closest to the first surface 2137 among multiple hole segments. That is, the first hole segment 21311 is the hole segment closest to or furthest from the interior of the outer shell 21 among multiple hole segments. During processing and manufacturing, the hole segments with larger cross-sectional areas can be processed first, and the first hole segment 21311 can be processed last. In this way, the first hole segment 21311 has higher precision, which is conducive to accurately controlling the burst pressure.

[0222] Referring to Figure 9, in some embodiments, the first surface 2137 faces the interior of the housing 21.

[0223] The first surface 2137 is the surface of the wall portion 213 closest to the interior of the outer casing 21, and the second surface 2138 is the surface of the wall portion 213 furthest from the interior of the outer casing 21. The first hole segment 21311 extends to the first surface 2137, that is, the first hole segment 21311 is the hole segment closest to the interior of the outer casing 21 among the multiple hole segments.

[0224] When the first surface 2137 faces the inside of the outer casing 21, the first hole segment 21311 is the hole segment closest to the inside of the outer casing 21 among the multiple hole segments. At this time, the pressure relief mechanism 22 is more likely to deform due to the change in air pressure inside the battery cell 20. Therefore, setting a first gap 2133 between the pressure relief mechanism 22 and the first step surface 2132 has a better effect and is more conducive to improving the reliability of the battery cell 20.

[0225] Please refer to Figure 10, which is a cross-sectional view of a battery cell 20 provided in some embodiments of this application. In some embodiments, the hole wall surface of the first hole segment 21311 and the first step surface 2132 are connected by a chamfered surface 2139.

[0226] "The hole wall of the first hole segment 21311 and the first step surface 2132 are connected by the chamfered surface 2139" can also be understood as the hole wall of the first hole segment 21311 and the first step surface 2132 are chamfered and transitioned.

[0227] The hole wall surface of the first hole section 21311 and the first step surface 2132 are transitioned by a chamfer, making the transition smooth. When the pressure relief mechanism 22 deforms due to the change in air pressure inside the battery cell 20, even if the pressure relief mechanism 22 collides with the chamfered surface 2139, the chamfered surface 2139 is not as sharp and the stress on the pressure relief mechanism 22 is also smaller, which is less likely to cause the pressure relief mechanism 22 to open the valve prematurely, thus improving the reliability of the battery cell 20.

[0228] Referring to Figure 10, in some embodiments, the chamfered surface 2139 extends circumferentially along the first hole segment 21311, and the cross-section of the chamfered surface 2139 is arc-shaped, with the cross-section perpendicular to the extending direction of the chamfered surface 2139.

[0229] "The chamfered surface 2139 extends circumferentially along the first hole segment 21311, and the cross-section of the chamfered surface 2139 is arc-shaped, with the cross-section perpendicular to the extension direction of the chamfered surface 2139" can also be understood as the hole wall surface of the first hole segment 21311 and the first step surface 2132 transitioning through a rounded corner.

[0230] The hole wall surface of the first hole section 21311 and the first step surface 2132 are transitioned by rounded corners, making the transition between the hole wall surface of the first hole section 21311 and the first step surface 2132 smoother. When the pressure relief mechanism 22 deforms due to the change in air pressure inside the battery cell 20, even if the pressure relief mechanism 22 collides with the chamfered surface 2139, since the chamfered surface 2139 is not as sharp, the stress of the chamfered surface 2139 on the pressure relief mechanism 22 is also smaller, which is less likely to cause the pressure relief mechanism 22 to open the valve prematurely, which is beneficial to improving the reliability of the battery cell 20.

[0231] Please refer to Figure 10. In some embodiments, the radius of the arc is R, which satisfies: 0.2mm≤R≤1mm.

[0232] R represents the radius of the arc, which is the radius of the fillet when rounding the corner.

[0233] The radius of the arc can be: R = 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0234] When R ≥ 0.2 mm, the radius of the arc is relatively large. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is more likely to collide with the chamfered surface 2139, rather than with other locations. This makes it less likely for the pressure relief mechanism 22 to open prematurely, which helps improve the reliability of the battery cell 20. When R ≤ 1 mm, the radius of the arc is not too large. On the one hand, this prevents the depth of the first hole segment 21311 from being too large, which helps reduce space occupation and allows the battery cell 20 to have a higher energy density. On the other hand, it facilitates manufacturing. When 0.2 mm ≤ R ≤ 1 mm, both the reliability and energy density of the battery cell 20 can be balanced, and manufacturing is also convenient.

[0235] Please refer to Figure 11, which is a cross-sectional view of a battery cell 20 provided in some other embodiments of this application. In some other embodiments, the chamfered surface 2139 extends circumferentially along the first hole segment 21311, and the cross-section of the chamfered surface 2139 is straight, with the cross-section perpendicular to the extending direction of the chamfered surface 2139.

[0236] "The chamfered surface 2139 extends circumferentially along the first hole segment 21311, and the cross-section of the chamfered surface 2139 is straight, with the cross-section perpendicular to the extension direction of the chamfered surface 2139" can also be understood as the hole wall surface of the first hole segment 21311 and the first step surface 2132 transitioning at an oblique angle.

[0237] The hole wall surface of the first hole section 21311 and the first step surface 2132 are transitioned by an oblique angle, making the transition between the hole wall surface of the first hole section 21311 and the first step surface 2132 smoother. When the pressure relief mechanism 22 deforms due to the change in air pressure inside the battery cell 20, even if the pressure relief mechanism 22 collides with the chamfered surface 2139, since the chamfered surface 2139 is not as sharp, the stress of the chamfered surface 2139 on the pressure relief mechanism 22 is also smaller, which is less likely to cause the pressure relief mechanism 22 to open the valve prematurely, which is beneficial to improving the reliability of the battery cell 20.

[0238] Referring to Figure 11, in some embodiments, along the first direction, the minimum distance from the connection point of the chamfered surface 2139 and the first stepped surface 2132 to the wall surface of the pressure relief hole 2131 is L1, satisfying: 0.2mm ≤ L1 ≤ 1mm. The first direction is perpendicular to the thickness direction of the wall portion 213. Along the thickness direction of the wall portion 213, the minimum distance from the connection point of the chamfered surface 2139 and the wall surface of the first hole segment 21311 to the first stepped surface 2132 is L2, 0.2mm ≤ L2 ≤ 1mm.

[0239] Please refer to Figure 11. The first direction can be the Y direction shown in the figure.

[0240] L1 represents the minimum distance along the first direction from the connection point between the chamfered surface 2139 and the first stepped surface 2132 to the wall surface of the pressure relief hole 2131. During measurement, multiple measurements can be taken and the average value can be used as L1.

[0241] The minimum distance from the connection position of the chamfered surface 2139 and the first step surface 2132 to the wall of the pressure relief hole 2131 along the first direction can be: L1 = 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0242] L2 represents the minimum distance from the connection point between the chamfered surface 2139 and the hole wall of the first hole segment 21311 along the thickness direction of the wall 213 to the first step surface 2132. During measurement, multiple measurements can be taken and the average value can be used as L2.

[0243] The minimum distance from the connection position between the chamfered surface 2139 and the hole wall of the first hole segment 21311 along the thickness direction of the wall 213 to the first step surface 2132 can be: L1 = 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0244] When L1 ≥ 0.2 mm and L2 ≥ 0.2 mm, the area of ​​the chamfered surface 2139 is relatively large. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is more likely to collide with the chamfered surface 2139, rather than with other locations. This makes it less likely for the pressure relief mechanism 22 to open prematurely, which helps improve the reliability of the battery cell 20. When L1 ≤ 1 mm and L2 ≤ 1 mm, the area of ​​the chamfered surface 2139 is not too large. On the one hand, this prevents the depth of the first hole segment 21311 from being too large, which helps reduce space occupation and allows the battery cell 20 to have a higher energy density. On the other hand, it facilitates manufacturing. When 0.2 mm ≤ L1 ≤ 1 mm and 0.2 mm ≤ L2 ≤ 1 mm, both the reliability and energy density of the battery cell 20 can be balanced, and manufacturing is also convenient.

[0245] Referring to Figure 11, in some embodiments, the outer peripheral surface of the pressure relief mechanism 22 is welded to the hole wall surface of the second hole section 21312.

[0246] The pressure relief mechanism 22 and the wall portion 213 can be welded together to achieve a welded connection between the outer peripheral surface of the pressure relief mechanism 22 and the wall surface of the second hole section 21312.

[0247] By welding the outer peripheral surface of the pressure relief mechanism 22 to the hole wall of the second hole section 21312, a butt weld relationship is formed between the pressure relief mechanism 22 and the wall 213. Butt welds require less heat, making the pressure relief mechanism 22 and the wall 213 less prone to deformation during welding, thus improving weld quality. Furthermore, when welding the outer peripheral surface of the pressure relief mechanism 22 to the hole wall of the second hole section 21312, matching the shape and size of the outer peripheral surface of the pressure relief mechanism 22 with the shape and size of the second hole section 21312 is sufficient to achieve high weld quality. Matching the shape and size of the outer peripheral surface of the pressure relief mechanism 22 with the shape and size of the second hole section 21312 is relatively simple; therefore, welding the outer peripheral surface of the pressure relief mechanism 22 to the hole wall of the second hole section 21312 is beneficial for improving weld quality.

[0248] Referring to Figure 11, in some embodiments, the wall portion 213 has a third surface 214, and one end of the second hole segment 21312 away from the first hole segment 21311 extends to the third surface 214, with the hole wall surface of the second hole segment 21312 connected to the third surface 214. Along the thickness direction of the wall portion 213, the pressure relief mechanism 22 has a fourth surface 224 facing away from the first hole segment 21311, and the distance between the third surface 214 and the fourth surface 224 is H3, satisfying: 0 ≤ H3 ≤ 0.3 mm.

[0249] "The end of the second hole segment 21312 away from the first hole segment 21311 extends to the third surface 214, and the hole wall of the second hole segment 21312 is connected to the third surface 214" can also be understood as the second hole segment 21312 being disposed on the third surface 214.

[0250] The fourth surface 224 is the surface of the pressure relief mechanism 22 that is away from the first hole section 21311 along the thickness direction of the wall portion 213. Along the direction from the wall portion 213 toward the inside of the outer casing 21, the third surface 214 may be closer to the inside of the outer casing 21 than the fourth surface 224, or the third surface 214 may be farther away from the inside of the outer casing 21 than the fourth surface 224, and the third surface 214 may also be flush with the fourth surface 224.

[0251] H3 represents the maximum distance between the third surface 214 and the fourth surface 224 along the thickness direction of the wall 213. During measurement, multiple measurements can be taken and the average value can be used as H3.

[0252] When the outer peripheral surface of the pressure relief mechanism 22 is welded to the hole wall of the second hole section 21312, the distance between the third surface 214 and the fourth surface 224 along the thickness direction of the wall 213 can be: H3 = 0, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, etc.

[0253] When 0≤H3≤0.3mm, the distance between the third surface 214 and the fourth surface 224 along the thickness direction of the wall 213 is small, which is beneficial to improving the quality of the butt weld.

[0254] Please refer to Figure 12, which is a cross-sectional view of a battery cell 20 provided in some other embodiments of this application. In some other embodiments, the wall portion 213 has a third surface 214, and one end of the second hole segment 21312 away from the first hole segment 21311 extends to the third surface 214, with the hole wall surface of the second hole segment 21312 connected to the third surface 214. The pressure relief mechanism 22 extends beyond the third surface 214 in the direction from the first hole segment 21311 to the second hole segment 21312, and the outer peripheral surface of the pressure relief mechanism 22 is welded to the third surface 214.

[0255] "The end of the second hole segment 21312 away from the first hole segment 21311 extends to the third surface 214, and the hole wall of the second hole segment 21312 is connected to the third surface 214" can also be understood as the second hole segment 21312 being disposed on the third surface 214. "The pressure relief mechanism 22 extends beyond the third surface 214 in the direction from the first hole segment 21311 to the second hole segment 21312" means that a part of the pressure relief mechanism 22 is accommodated in the second hole segment 21312, and the other part of the pressure relief mechanism 22 extends out of the second hole segment 21312 in the direction from the first hole segment 21311 to the second hole segment 21312.

[0256] The pressure relief mechanism 22 and the wall portion 213 can be connected by fillet weld to achieve the welding connection between the outer peripheral surface of the pressure relief mechanism 22 and the third surface 214.

[0257] By welding the outer peripheral surface of the pressure relief mechanism 22 to the third surface 214, the pressure relief mechanism 22 and the wall portion 213 are connected by fillet weld, thereby achieving a welded connection between the pressure relief mechanism 22 and the wall portion 213. This structure enables a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the pressure relief mechanism 22 and the wall portion 213, thereby effectively improving the connection stability between the pressure relief mechanism 22 and the wall portion 213.

[0258] Referring to Figure 12, in some embodiments, along the thickness direction of the wall portion 213, the pressure relief mechanism 22 has a fourth surface 224 that is opposite to the first hole segment 21311, and the distance between the third surface 214 and the fourth surface 224 is H3, which satisfies: H3 > 0.3 mm.

[0259] When the outer peripheral surface of the pressure relief mechanism 22 is welded to the third surface 214, the distance between the third surface 214 and the fourth surface 224 along the thickness direction of the wall 213 can be: H3 = 0.32mm, 0.35mm, 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.5mm, etc.

[0260] When H3 > 0.3 mm, the distance between the third surface 214 and the fourth surface 224 along the thickness direction of the wall 213 is relatively large, which is beneficial to improving the quality of the fillet weld.

[0261] Please refer to Figure 13, which is a cross-sectional view of the battery cell 20 provided in some other embodiments of this application. In some other embodiments, the wall portion 213 has a third surface 214, and one end of the second hole segment 21312 away from the first hole segment 21311 extends to the third surface 214, with the hole wall surface of the second hole segment 21312 connected to the third surface 214. Along the thickness direction of the wall portion 213, the pressure relief mechanism 22 includes a connecting portion 223 disposed opposite to the third surface 214, and the connecting portion 223 is welded to the third surface 214.

[0262] The connecting portion 223 is the part of the pressure relief mechanism 22 used for welding to the wall portion 213, and the connecting portion 223 is disposed opposite to the third surface 214 along the thickness direction of the wall portion 213. In some embodiments, the connecting portion 223 may be a flange disposed on the pressure relief mechanism 22.

[0263] The connecting part 223 can be welded through the wall part 213 to achieve the welding of the connecting part 223 to the third surface 214.

[0264] The pressure relief mechanism 22 includes a connecting portion 223 disposed opposite to the third surface 214, and the connecting portion 223 is welded to the third surface 214. When welding the connecting portion 223 to the third surface 214, penetration welding can be used. The wall portion 213 has a large thickness in the area where the third surface 214 is located, so it is not easy to weld through the wall portion 213 during welding. The welding effect between the connecting portion 223 and the wall portion 213 is better, which is beneficial to improving the connection stability between the pressure relief mechanism 22 and the wall portion 213.

[0265] Referring to Figure 13, in some embodiments, the base material of the pressure relief mechanism 22 is aluminum. Along the thickness direction of the wall portion 213, the thickness of the pressure relief mechanism 22 is H4, satisfying: 0.2mm ≤ H4 ≤ 0.8mm.

[0266] "The base material of the pressure relief mechanism 22 is aluminum" means that aluminum is the material with the highest mass percentage in the pressure relief mechanism 22. The material of the pressure relief mechanism 22 can be pure aluminum or aluminum alloy.

[0267] H4 represents the thickness of the pressure relief mechanism 22 along the thickness direction of the wall portion 213. It should be noted that the thickness of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 refers to the thickness of the pressure relief mechanism 22 at a non-weak location. For example, in an embodiment where the pressure relief mechanism 22 has a first groove 221 and a second groove 222, with the first groove 221 located at the bottom surface of the second groove 222, and the pressure relief mechanism 22 is configured to crack along at least a portion of the first groove 221 to release pressure when the pressure inside the housing 21 reaches a threshold, the thickness of the wall portion 213 of the pressure relief mechanism 22 in the thickness direction is the thickness of the area of ​​the pressure relief mechanism 22 excluding the first groove 221 and the second groove 222. Furthermore, in an embodiment where the pressure relief mechanism 22 includes a connecting portion 223 disposed opposite to the third surface 214, and the connecting portion 223 is welded to the third surface 214, the thickness of the wall portion 213 of the pressure relief mechanism 22 in the thickness direction is the thickness of the area of ​​the pressure relief mechanism 22 excluding the first groove 221, the second groove 222, and the connecting portion 223. In other words, when measuring the thickness of the pressure relief mechanism 22, the thickness of the main body area of ​​the pressure relief mechanism 22 should be measured. Multiple measurements can be taken, and the average value can be used as H4.

[0268] When the base material of the pressure relief mechanism 22 is aluminum, the thickness of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 can be: H4 = 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, etc.

[0269] Because aluminum has low strength, when the base material of the pressure relief mechanism 22 is aluminum, the thickness of the pressure relief mechanism 22 can be increased to obtain higher strength. When the base material of the pressure relief mechanism 22 is aluminum and H4 ≥ 0.2 mm, the pressure relief mechanism 22 has a larger thickness and higher strength. The deformation of the pressure relief mechanism 22 due to changes in air pressure inside the battery cell 20 is smaller, making it less likely for the pressure relief mechanism 22 to collide with the connection position between the hole wall of the first hole section 21311 and the first step surface 2132, and less likely to cause premature valve opening, which is beneficial to improving the reliability of the battery cell 20. When the base material of the pressure relief mechanism 22 is aluminum and H4 ≤ 0.8 mm, the thickness of the pressure relief mechanism 22 is not too large, which helps to reduce the space occupied and improve the energy density of the battery cell 20. Therefore, when the base material of the pressure relief mechanism 22 is aluminum and 0.2 mm ≤ H4 ≤ 0.8 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0270] Optionally, 0.3mm ≤ H4 ≤ 0.6mm.

[0271] When the base material of the pressure relief mechanism 22 is aluminum, the thickness of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 can be: H4 = 0.3mm, 0.32mm, 0.35mm, 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.48mm, 0.5mm, 0.52mm, 0.55mm, 0.58mm, 0.6mm, etc.

[0272] When the base material of the pressure relief mechanism 22 is aluminum and H4 ≥ 0.3 mm, the pressure relief mechanism 22 has a larger thickness and higher strength. The deformation of the pressure relief mechanism 22 due to changes in internal air pressure of the battery cell 20 is smaller, making it less likely to collide with the connection between the hole wall of the first hole segment 21311 and the first step surface 2132, and less likely to cause premature valve opening, thus improving the reliability of the battery cell 20. When the base material of the pressure relief mechanism 22 is aluminum and H4 ≤ 0.6 mm, the thickness of the pressure relief mechanism 22 is not excessive, which helps reduce space occupation and improves the energy density of the battery cell 20. Therefore, when the base material of the pressure relief mechanism 22 is aluminum and 0.3 mm ≤ H4 ≤ 0.6 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0273] In other embodiments, the base material of the pressure relief mechanism 22 is iron. Along the thickness direction of the wall portion 213, the thickness of the pressure relief mechanism 22 is H4, satisfying: 0.1mm ≤ H4 ≤ 0.4mm.

[0274] "The base material of the pressure relief mechanism 22 is iron" means that iron is the material with the highest mass percentage in the pressure relief mechanism 22. For example, the material of the pressure relief mechanism 22 can be carbon steel or stainless steel. Carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel.

[0275] When the base material of the pressure relief mechanism 22 is iron, the thickness of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 can be: H4 = 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.35mm, 0.38mm, 0.4mm, etc.

[0276] Because iron has high strength, using iron as the base material for the pressure relief mechanism 22 results in higher strength, allowing for a reduction in its thickness. When the base material of the pressure relief mechanism 22 is iron, and H4 ≥ 0.1 mm, the larger thickness results in higher strength. This reduces the deformation caused by pressure changes within the battery cell 20, making it less likely to collide with the connection between the hole wall of the first hole segment 21311 and the first step surface 2132, thus preventing premature valve opening and improving the reliability of the battery cell 20. When the base material of the pressure relief mechanism 22 is iron, and H4 ≤ 0.4 mm, the thickness is not excessive, reducing space requirements and improving the energy density of the battery cell 20. Therefore, using iron as the base material for the pressure relief mechanism 22, with 0.1 mm ≤ H4 ≤ 0.4 mm, balances the reliability and energy density of the battery cell 20.

[0277] Optionally, 0.15mm ≤ H4 ≤ 0.3mm.

[0278] When the base material of the pressure relief mechanism 22 is iron, the thickness of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 can be: H4 = 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, etc.

[0279] When the base material of the pressure relief mechanism 22 is iron, and H4 ≥ 0.15 mm, the pressure relief mechanism 22 has a larger thickness and higher strength. The deformation of the pressure relief mechanism 22 due to changes in internal air pressure of the battery cell 20 is smaller, making it less likely to collide with the connection between the hole wall of the first hole segment 21311 and the first step surface 2132, and less likely to cause premature valve opening, thus improving the reliability of the battery cell 20. When the base material of the pressure relief mechanism 22 is iron, and H4 ≤ 0.3 mm, the thickness of the pressure relief mechanism 22 is not excessive, which helps reduce space occupation and improves the energy density of the battery cell 20. Therefore, when the base material of the pressure relief mechanism 22 is iron, and 0.15 mm ≤ H4 ≤ 0.3 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0280] Referring to Figure 13, in some embodiments, the size of the second hole segment 21312 along the thickness direction of the wall portion 213 is H5, satisfying: 0.25mm≤H5≤1.5mm.

[0281] H5 represents the dimension of the second hole segment 21312 along the thickness direction of the wall portion 213. During measurement, multiple measurements can be taken and the average value can be used as H5.

[0282] The dimensions of the second hole section 21312 along the thickness direction of the wall portion 213 can be: H5 = 0.25mm, 0.28mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0283] When H5 ≥ 0.25 mm, the second hole segment 21312 has a larger dimension along the thickness direction of the wall portion 213. On the one hand, this allows for a larger capacity to accommodate the pressure relief mechanism 22, reducing the length of the pressure relief mechanism 22 extending out of the second hole segment 21312 in the direction away from the first hole segment 21311. This helps reduce the risk of interference between other components and the pressure relief mechanism 22, thus improving the reliability of the battery cell 20. Furthermore, it allows for a larger dimension of the first gap 2133 along the thickness direction of the wall portion 213, and a greater distance between the pressure relief mechanism 22 and the first step surface 2132. When the pressure relief mechanism 22 deforms due to changes in internal air pressure within the battery cell 20, it is less likely to collide with the connection point between the hole wall of the first hole segment 21311 and the first step surface 2132, reducing the likelihood of premature valve opening and further improving the reliability of the battery cell 20. On the other hand, when welding the pressure relief mechanism 22 to the wall of the second hole section 21312, the larger dimension of the hole wall along the thickness direction of the wall portion 213 makes welding easier and improves welding quality. When H5 ≤ 1.5mm, the dimension of the second hole section 21312 along the thickness direction of the wall portion 213 is not too large, which helps to reduce space occupation and increase the energy density of the battery cell 20. Therefore, when 0.25mm ≤ H5 ≤ 1.5mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0284] Optionally, 0.3mm ≤ H5 ≤ 1mm.

[0285] The dimensions of the second hole section 21312 along the thickness direction of the wall portion 213 can be: H5 = 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, etc.

[0286] When H5 ≥ 0.3 mm, the second hole segment 21312 has a larger dimension along the thickness direction of the wall 213. On the one hand, it can accommodate the pressure relief mechanism 22 to a greater extent, reducing the length of the pressure relief mechanism 22 extending out of the second hole segment 21312 in the direction away from the first hole segment 21311. This helps reduce the risk of interference between other components and the pressure relief mechanism 22, and improves the reliability of the battery cell 20. Furthermore, it also allows the first gap 2133 to have a larger dimension along the thickness direction of the wall 213, and the pressure relief mechanism 22 to be farther away from the first step surface 2132. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely to collide with the connection position between the hole wall surface of the first hole segment 21311 and the first step surface 2132, and it is less likely to cause the pressure relief mechanism 22 to open prematurely, which helps improve the reliability of the battery cell 20. On the other hand, when welding the pressure relief mechanism 22 to the wall of the second hole section 21312, the dimension of the hole wall of the second hole section 21312 along the thickness direction of the wall portion 213 is larger, making welding easier and improving welding quality. When H5 ≤ 1mm, the dimension of the second hole section 21312 along the thickness direction of the wall portion 213 is not too large, which helps to reduce space occupation and increase the energy density of the battery cell 20. Therefore, when 0.3mm ≤ H5 ≤ 1mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0287] Referring to Figure 13, in some embodiments, the size of the first hole segment 21311 along the thickness direction of the wall portion 213 is H6, satisfying: 0.2mm≤H6≤2mm.

[0288] H6 represents the dimension of the first hole segment 21311 along the thickness direction of the wall portion 213. During measurement, multiple measurements can be taken and the average value can be used as H6.

[0289] The dimensions of the first hole segment 21311 along the thickness direction of the wall portion 213 can be: H6 = 0.2mm, 0.25mm, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, etc.

[0290] When H6 ≥ 0.2 mm, the dimension of the first hole segment 21311 along the thickness direction of the wall portion 213 is relatively large, and the thickness of the wall portion 213 in the region where the first step surface 2132 is located is also relatively large. This allows the first step surface 2132 to better support the pressure relief mechanism 22. When laser welding is used to weld the pressure relief mechanism 22 and the wall portion 213, the first step surface 2132 can effectively block the laser, making it less likely for the laser to penetrate the wall portion 213, which is beneficial to improving the reliability of the battery cell 20. When H6 ≤ 2 mm, the dimension of the first hole segment 21311 along the thickness direction of the wall portion 213 is not too large, which is beneficial to reducing space occupation and improving the energy density of the battery cell 20. Therefore, when 0.2 mm ≤ H6 ≤ 2 mm, both the reliability and energy density of the battery cell 20 can be balanced.

[0291] Optionally, 0.3mm ≤ H6 ≤ 1.5mm.

[0292] The dimensions of the first hole segment 21311 along the thickness direction of the wall portion 213 can be: H6 = 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0293] When H6 ≥ 0.3 mm, the dimension of the first hole segment 21311 along the thickness direction of the wall portion 213 is larger, and the thickness of the wall portion 213 in the region where the first step surface 2132 is located is also larger. This allows the first step surface 2132 to better support the pressure relief mechanism 22. When laser welding is used to weld the pressure relief mechanism 22 and the wall portion 213, the first step surface 2132 can better block the laser, making it less likely for the laser to penetrate the wall portion 213, which is beneficial to improving the reliability of the battery cell 20. When H6 ≤ 1.5 mm, the dimension of the first hole segment 21311 along the thickness direction of the wall portion 213 is not too large, which is beneficial to reducing space occupation and improving the energy density of the battery cell 20. Therefore, when 0.3 mm ≤ H6 ≤ 1.5 mm, it is possible to better balance the reliability and energy density of the battery cell 20.

[0294] Referring to Figure 13, in some embodiments, the pressure relief mechanism 22 is provided with a first groove 221. The pressure relief mechanism 22 is configured to split at least a portion along the first groove 221 when the pressure inside the housing 21 reaches a threshold, thereby releasing the pressure. The first groove 221 is projected along the thickness direction of the wall portion 213 within the first hole segment 21311.

[0295] The pressure relief mechanism 22 is provided with a first groove 221. The pressure relief mechanism 22 is relatively weak at the location where the first groove 221 is provided. When the internal pressure of the battery cell 20 reaches the threshold, the pressure relief mechanism 22 can crack along at least part of the first groove 221 under the action of internal pressure to release the internal pressure of the battery cell 20.

[0296] The first groove 221 can be formed by various methods, such as stamping or cold heading. Taking the stamping method for forming the first groove 221 as an example, the first groove 221 can be stamped on the pressure relief mechanism 22 along the thickness direction of the wall 213.

[0297] By using stamping or cold forging to form the first groove 221, the groove wall of the first groove 221 undergoes work hardening (the grain arrangement changes, leading to lattice distortion, reducing the metal's plasticity, and increasing the material's hardness), thus enhancing its resistance to external impacts and making it less susceptible to damage from external impacts. This helps reduce the risk of leakage from the pressure relief mechanism 22.

[0298] The first groove 221 defines a pressure relief area. When the first groove 221 is an annular groove, the pressure relief area is a portion of the area enclosed by the first groove 221 in the pressure relief mechanism 22. When the first groove 221 is a non-annular structure, the pressure relief area is a portion of the area enclosed by the first groove 221 itself and the line connecting its two ends. The pressure relief area is used to open when the battery cell 20 is depressurized, forming an opening for the fluid medium to pass through.

[0299] The projection of the first groove 221 along the thickness direction of the wall portion 213 is located within the first hole segment 21311. In other words, the projection of the hole wall surface of the first hole segment 21311 along the thickness direction of the wall portion 213 surrounds the outside of the first groove 221.

[0300] The pressure relief mechanism 22 is relatively weak at the location where the first groove 221 is set. When the battery cell 20 is depressurized, the pressure relief mechanism 22 can split at least part of the first groove 221 to open and release pressure. By making the projection of the first groove 221 along the thickness direction of the wall 213 located within the first hole segment 21311, that is, the cross-sectional area of ​​the first hole segment 21311 is larger than the area of ​​the pressure relief area defined by the first groove 221 (the pressure relief area opens when the battery cell 20 is depressurized, forming an opening for the fluid medium to pass through), when the battery cell 20 is depressurized, the fluid medium inside the outer casing 21 can quickly pass through the first hole segment 21311 and act on the pressure relief mechanism 22, so that the pressure relief mechanism 22 can open and release pressure quickly, which helps to improve the timeliness of pressure relief of the battery cell 20. In addition, when the pressure relief mechanism 22 deforms due to the change in air pressure inside the battery cell 20, the pressure relief area is less likely to collide with the connection position of the hole wall surface of the first hole section 21311 and the first step surface 2132, which is less likely to cause the pressure relief mechanism 22 to open the valve prematurely, which is beneficial to improving the reliability of the battery cell 20.

[0301] Referring to Figure 13, in some embodiments, along the first direction, the minimum distance between the hole wall of the first hole segment 21311 and the first groove 221 is L3, satisfying: 1mm≤L3≤3mm. The first direction is perpendicular to the thickness direction of the wall portion 213.

[0302] L3 represents the minimum distance between the hole wall of the first hole segment 21311 and the first groove 221 along the first direction. During measurement, the distance from the position of the hole wall of the first hole segment 21311 closest to the first groove 221 to the first groove 221 is measured. Multiple measurements can be taken and the average value is taken as L3.

[0303] The minimum distance between the hole wall of the first hole segment 21311 and the first groove 221 along the first direction can be: L3 = 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, etc.

[0304] When L3 ≥ 1 mm, the minimum distance between the hole wall of the first hole segment 21311 and the first groove 221 along the first direction is relatively large. When the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, the pressure relief area is less likely to collide with the connection position between the hole wall of the first hole segment 21311 and the first step surface 2132, thus preventing the pressure relief mechanism 22 from opening prematurely and improving the reliability of the battery cell 20. When L3 ≤ 3 mm, the minimum distance between the hole wall of the first hole segment 21311 and the first groove 221 along the first direction is not too large, resulting in a larger area of ​​the pressure relief area, which is beneficial for the rapid pressure relief of the battery cell 20 and improves its reliability. Therefore, when 1 mm ≤ L3 ≤ 3 mm, it is beneficial to improve the reliability of the battery cell 20.

[0305] Referring to Figure 13, in some embodiments, the pressure relief mechanism 22 is provided with a second groove 222, and the first groove 221 is provided on the bottom surface of the second groove 222.

[0306] The pressure relief mechanism 22 is provided with a second groove 222, and the first groove 221 and the second groove 222 are arranged along the thickness direction of the wall portion 213. The opening of the first groove 221 is formed on the bottom surface of the second groove 222.

[0307] The second groove 222 can be a single-level groove or a multi-level groove. When the second groove 222 is a multi-level groove, the pressure relief mechanism 22 has a fourth surface 224 and a fifth surface 225 disposed opposite to each other in the thickness direction of the wall portion 213, and the second groove 222 includes multi-level grooves arranged sequentially along the direction from the fourth surface 224 to the fifth surface 225. In two adjacent levels of grooves, the first-level groove furthest from the fourth surface 224 is disposed on the bottom surface of the first-level groove closest to the fourth surface 224. The first groove 221 is disposed on the bottom surface of the first-level groove furthest from the fourth surface 224 among the multi-level grooves.

[0308] The opening of the first groove 221 is formed on the bottom surface of the second groove 222. During manufacturing, the second groove 222 can be formed first, and then the first groove 221 can be formed, thereby reducing the forming force on the pressure relief mechanism 22, reducing the risk of cracks in the pressure relief mechanism 22, and improving the reliability of the battery cell 20.

[0309] Referring to Figure 13, in some embodiments, the second groove 222 is projected along the thickness direction of the wall 213 into the first hole segment 21311.

[0310] It should be noted that when the projection of the second groove 222 along the thickness direction of the wall portion 213 overlaps with the boundary of the hole wall surface of the first hole segment 21311, it is also considered that the projection of the second groove 222 along the thickness direction of the wall portion 213 is located within the first hole segment 21311.

[0311] The projection of the second groove 222 along the thickness direction of the wall 213 is located within the first hole section 21311. When the pressure relief mechanism 22 deforms due to the change in air pressure inside the battery cell 20, the bottom wall 2112 of the second groove 222 is less likely to collide with the connection position of the hole wall surface of the first hole section 21311 and the first step surface 2132. The area outside the second groove 222 of the pressure relief mechanism 22 is thicker. Even if the area outside the second groove 222 of the pressure relief mechanism 22 collides with the connection position of the hole wall surface of the first hole section 21311 and the first step surface 2132, it is less likely to cause the pressure relief mechanism 22 to open the valve prematurely, which is beneficial to improving the reliability of the battery cell 20.

[0312] Referring to Figure 13, in some embodiments, the minimum distance between the hole wall of the first hole segment 21311 and the groove side of the second groove 222 along the first direction is L4, which satisfies: 0≤L4≤2mm.

[0313] L4 represents the minimum distance between the hole wall of the first hole segment 21311 along the first direction and the groove side of the second groove 222. During measurement, the distance from the position of the hole wall of the first hole segment 21311 closest to the groove side of the second groove 222 to the groove side of the second groove 222 is measured. Multiple measurements can be taken and the average value is taken as L4.

[0314] It should be noted that in the embodiment where the second groove 222 is a multi-level groove, L4 represents the minimum distance between the hole wall surface of the first hole segment 21311 and the groove side surface of the groove furthest from the first groove 221 in the multi-level groove along the first direction.

[0315] The minimum distance between the hole wall of the first hole segment 21311 and the groove side of the second groove 222 along the first direction can be: L4 = 0, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, etc.

[0316] When L4≥0, when the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, the bottom wall 2112 of the second groove 222 is less likely to collide with the connection position between the hole wall surface of the first hole section 21311 and the first step surface 2132. The area outside the second groove 222 of the pressure relief mechanism 22 has a larger thickness. Even if the area outside the second groove 222 of the pressure relief mechanism 22 collides with the connection position between the hole wall surface of the first hole section 21311 and the first step surface 2132, it is less likely to cause the pressure relief mechanism 22 to open prematurely, which is beneficial to improving the reliability of the battery cell 20. When L4≤2mm, the minimum distance between the hole wall surface of the first hole section 21311 along the first direction and the side surface of the second groove 222 is not too large, which is beneficial to making the area of ​​the pressure relief zone larger, which is beneficial to the rapid pressure relief of the battery cell 20 and improves the reliability of the battery cell 20.

[0317] Optionally, 0.3mm≤L4≤1mm.

[0318] The minimum distance between the hole wall of the first hole segment 21311 and the groove side of the second groove 222 along the first direction can be: L4 = 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0319] When L4 ≥ 0.3 mm, when the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, the bottom wall 2112 of the second groove 222 is less likely to collide with the connection position between the hole wall of the first hole segment 21311 and the first step surface 2132. The area outside the second groove 222 of the pressure relief mechanism 22 is thicker. Even if the area outside the second groove 222 of the pressure relief mechanism 22 collides with the connection position between the hole wall of the first hole segment 21311 and the first step surface 2132, it is less likely to cause the pressure relief mechanism 22 to open prematurely, which is beneficial to improving the reliability of the battery cell 20. When L4 ≤ 1 mm, the minimum distance between the hole wall of the first hole segment 21311 along the first direction and the side of the groove 222 is not too large, which is beneficial to making the area of ​​the pressure relief zone larger, which is more conducive to the rapid pressure relief of the battery cell 20 and improves the reliability of the battery cell 20.

[0320] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0321] 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.

[0322] Please refer to Figures 3 to 13 for some embodiments of this application.

[0323] This application provides a battery cell 20, which includes a housing 21 and a pressure relief mechanism 22. The housing 21 has a wall portion 213, and the wall portion 213 is provided with a pressure relief hole 2131, which penetrates the wall portion 213 along its thickness direction. The pressure relief hole 2131 includes a plurality of hole segments arranged along the thickness direction of the wall portion 213. The plurality of hole segments include adjacent first hole segments 21311 and second hole segments 21312. The hole wall surfaces of the first hole segment 21311 and the second hole segment 21312 are connected by a first step surface 2132. The cross-sectional area of ​​the second hole segment 21312 is larger than the cross-sectional area of ​​the first hole segment 21311, and the cross-section is perpendicular to the thickness direction of the wall portion 213. The pressure relief mechanism 22 is at least partially located within the second hole segment 21312 and faces the first step surface 2132. The projection of the pressure relief mechanism 22 along the thickness direction of the wall portion 213 covers the first hole segment 21311. A first gap 2133 exists between the pressure relief mechanism 22 and the first step surface 2132 along the thickness direction of the wall portion 213. By accommodating the pressure relief mechanism 22 within the second hole segment 21312, on the one hand, the height of the pressure relief mechanism 22 protruding from the wall portion 213 can be reduced, lowering the risk of interference between the pressure relief mechanism 22 and other components, and reducing the space occupied by the pressure relief mechanism 22, which is beneficial for improving the energy density of the battery cell 20. On the other hand, the second hole segment 21312 can position the pressure relief mechanism 22, simplifying assembly. Furthermore, when the pressure relief mechanism 22 is connected to the wall portion 213 by welding, the first step surface 2132 can block laser light, thereby reducing the risk of laser damage to other components. Furthermore, by creating a first gap 2133 between the pressure relief mechanism 22 and the first step surface 2132, when the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, it is less likely to collide with the connection between the hole wall of the first hole section 21311 and the first step surface 2132, thus preventing the pressure relief mechanism 22 from opening prematurely and improving the reliability of the battery cell 20.

[0324] The multiple segments include a third segment 21313 adjacent to the second segment 21312. The second segment 21312 connects the first segment 21311 and the third segment 21313. The cross-sectional area of ​​the third segment 21313 is larger than that of the second segment 21312. The battery cell 20 includes a protective element 26, which is disposed on the side of the third segment 21313 opposite to the second segment 21312 and covers the third segment 21313. By providing the protective element 26, on the one hand, the risk of the pressure relief mechanism 22 being subjected to external forces on the side opposite to the first segment 21311 can be reduced, making it less likely for the pressure relief mechanism 22 to open prematurely, thus improving the reliability of the battery cell 20. On the other hand, the protective element 26 can shield impurities, making it less likely for impurities to fall onto the pressure relief mechanism 22 and less likely to affect the normal opening of the pressure relief mechanism 22, thus improving the reliability of the battery cell 20. Furthermore, by providing a second gap 2134 between the pressure relief mechanism 22 and the protective member 26, the pressure relief mechanism 22 is less likely to interfere with the protective member 26 when it deforms due to changes in the internal air pressure of the battery cell 20. This also allows the pressure relief mechanism 22 to open a larger opening during pressure relief of the battery cell 20, enabling rapid pressure relief and improving the reliability of the battery cell 20. By providing a third hole segment 21313, on the one hand, the third hole segment 21313 allows the protective member 26 to be moved away from the pressure relief mechanism 22, meaning at least a portion of the third hole segment 21313 can serve as the second gap 2134. On the other hand, a portion of the pressure relief mechanism 22 can be accommodated within the third hole segment 21313, which helps reduce the depth requirement of the second hole segment 21312, thus facilitating manufacturing.

[0325] The plurality of holes include a fourth hole segment 21314 adjacent to the third hole segment 21313. The third hole segment 21313 connects the second hole segment 21312 and the fourth hole segment 21314. The cross-sectional area of ​​the fourth hole segment 21314 is larger than that of the third hole segment 21313. The protective member 26 is at least partially accommodated in the fourth hole segment 21314. By accommodating the protective member 26 at least partially in the fourth hole segment 21314, it is beneficial to reduce the height of the protective member 26 protruding from the surface of the wall portion 213 away from the interior of the outer casing 21. On the one hand, this helps to reduce the volume occupied by the protective member 26 in the battery device 100, which helps to improve the energy density of the battery device 100. On the other hand, it helps to reduce the risk of interference between the protective member 26 and other components. In addition, the fourth hole segment 21314 can, to a certain extent, position the protective member 26, thereby facilitating the quick installation of the protective member 26.

[0326] The hole wall of the first hole segment 21311 and the first step surface 2132 are connected by a chamfered surface 2139. The chamfered transition between the hole wall of the first hole segment 21311 and the first step surface 2132 makes the transition smooth. When the pressure relief mechanism 22 deforms due to the change in air pressure inside the battery cell 20, even if the pressure relief mechanism 22 collides with the chamfered surface 2139, the chamfered surface 2139 is not as sharp and the stress on the pressure relief mechanism 22 is also smaller, which is less likely to cause the pressure relief mechanism 22 to open the valve prematurely, thus improving the reliability of the battery cell 20.

[0327] The pressure relief mechanism 22 is provided with a first groove 221. The pressure relief mechanism 22 is configured to split at least a portion of the first groove 221 when the pressure inside the housing 21 reaches a threshold, thereby releasing the pressure. The first groove 221 is projected along the thickness direction of the wall portion 213 within the first hole segment 21311. The pressure relief mechanism 22 is relatively weak at the location where the first groove 221 is provided. When the battery cell 20 is depressurized, the pressure relief mechanism 22 can split at least a portion of the first groove 221, thereby opening the pressure relief mechanism 22 to release pressure. By positioning the projection of the first groove 221 along the thickness direction of the wall 213 within the first hole segment 21311—that is, by making the cross-sectional area of ​​the first hole segment 21311 larger than the area of ​​the pressure relief zone defined by the first groove 221 (the pressure relief zone opens when the battery cell 20 is depressurized, forming an opening for the fluid medium to pass through)—the fluid medium inside the outer casing 21 can quickly pass through the first hole segment 21311 and act on the pressure relief mechanism 22 when the battery cell 20 is depressurized. This allows the pressure relief mechanism 22 to open quickly and relieve pressure, improving the timeliness of pressure relief for the battery cell 20. Furthermore, when the pressure relief mechanism 22 deforms due to changes in the internal air pressure of the battery cell 20, the pressure relief zone is less likely to collide with the connection between the hole wall of the first hole segment 21311 and the first step surface 2132, preventing premature opening of the pressure relief mechanism 22 and improving the reliability of the battery cell 20.

[0328] 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, wherein, include: The outer casing has a wall portion, the wall portion being provided with a pressure relief hole, the pressure relief hole penetrating the wall portion along its thickness direction, the pressure relief hole comprising a plurality of hole segments arranged along the thickness direction of the wall portion, the plurality of hole segments including adjacent first hole segments and second hole segments, the hole wall surfaces of the first hole segment and the hole wall surfaces of the second hole segment being connected by a first stepped surface, the cross-sectional area of ​​the second hole segment being larger than the cross-sectional area of ​​the first hole segment, the cross-section being perpendicular to the thickness direction of the wall portion; A pressure relief mechanism is located at least partially within the second hole section and is disposed facing the first step surface. The projection of the pressure relief mechanism along the thickness direction of the wall covers the first hole section. Along the thickness direction of the wall portion, there is a first gap between the pressure relief mechanism and the first stepped surface.

2. The battery cell of claim 1, wherein, Along the thickness direction of the wall portion, the size of the first gap is H1, which satisfies: 0.05mm≤H1≤1mm, and optionally, 0.1mm≤H1≤0.5mm.

3. The battery cell of claim 1 or 2, wherein, The battery cell includes a protective component, which is disposed on the wall portion and located on the side of the pressure relief mechanism away from the first hole section; Along the thickness direction of the wall portion, the projection of the protective member covers the pressure relief mechanism, and there is a second gap between the pressure relief mechanism and the protective member.

4. The battery cell of claim 3, wherein, Along the thickness direction of the wall portion, the size of the second gap is H2, which satisfies: 0.05mm≤H2≤0.3mm, and optionally, 0.1mm≤H2≤0.25mm.

5. The battery cell of claim 3 or 4, wherein, The plurality of hole segments include a third hole segment adjacent to the second hole segment, the second hole segment connecting the first hole segment and the third hole segment, and the cross-sectional area of ​​the third hole segment being greater than the cross-sectional area of ​​the second hole segment; The protective element is disposed on the side of the third hole segment opposite to the second hole segment and covers the third hole segment.

6. The battery cell of claim 5, wherein, A portion of the pressure relief mechanism is housed in the second orifice, and another portion of the pressure relief mechanism is housed in the third orifice.

7. The battery cell of claim 5 or 6, wherein, The wall is provided with a flow channel, which connects the third hole section and the outside of the outer shell.

8. The battery cell of any one of claims 5-7, wherein, The plurality of hole segments include a fourth hole segment adjacent to the third hole segment, the third hole segment connecting the second hole segment and the fourth hole segment, and the cross-sectional area of ​​the fourth hole segment being larger than the cross-sectional area of ​​the third hole segment; The protective element is at least partially accommodated in the fourth hole segment.

9. The battery cell of claim 8, wherein, The protective element is completely contained within the fourth hole section.

10. The battery cell of claim 8 or 9, wherein, The wall surface of the third hole section and the wall surface of the fourth hole section are connected by a second stepped surface, and the protective member abuts against the second stepped surface.

11. The battery cell of any one of claims 1-10, wherein, Along the thickness direction of the wall portion, the wall portion has opposing first and second surfaces, the pressure relief hole penetrates the first surface and the second surface, and the first hole segment is the hole segment closest to the first surface among the plurality of hole segments.

12. The battery cell of claim 11, wherein, The first surface faces the interior of the housing.

13. The battery cell of any one of claims 1-12, wherein, The wall surface of the first hole segment is connected to the first step surface through a chamfered surface.

14. The battery cell of claim 13, wherein, The chamfered surface extends circumferentially along the first hole segment, and the cross-section of the chamfered surface is arc-shaped, with the cross-section perpendicular to the extension direction of the chamfered surface.

15. The battery cell of claim 14, wherein, The radius of the arc is R, which satisfies: 0.2mm≤R≤1mm.

16. The battery cell of claim 13, wherein, The chamfered surface extends circumferentially along the first hole segment, and the cross-section of the chamfered surface is linear, with the cross-section perpendicular to the extension direction of the chamfered surface.

17. The battery cell of claim 16, wherein, Along the first direction, the minimum distance from the connection position of the chamfered surface and the first step surface to the wall surface of the pressure relief hole is L1, which satisfies: 0.2mm≤L1≤1mm, and the first direction is perpendicular to the thickness direction of the wall. Along the thickness direction of the wall portion, the minimum distance from the connection position of the chamfered surface and the hole wall of the first hole segment to the first step surface is L2, 0.2mm≤L2≤1mm.

18. The battery cell of any one of claims 1-17, wherein, The outer peripheral surface of the pressure relief mechanism is welded to the hole wall surface of the second hole section.

19. The battery cell of claim 18, wherein, The wall portion has a third surface, and one end of the second hole segment away from the first hole segment extends to the third surface, with the hole wall surface of the second hole segment connected to the third surface; Along the thickness direction of the wall portion, the pressure relief mechanism has a fourth surface facing away from the first hole segment, and the distance between the third surface and the fourth surface is H3, satisfying: 0≤H3≤0.3mm.

20. The battery cell of any one of claims 1-17, wherein, The wall portion has a third surface, and one end of the second hole segment away from the first hole segment extends to the third surface, with the hole wall surface of the second hole segment connected to the third surface; The pressure relief mechanism extends beyond the third surface in the direction from the first hole segment to the second hole segment, and the outer peripheral surface of the pressure relief mechanism is welded to the third surface.

21. The battery cell of claim 20, wherein, Along the thickness direction of the wall portion, the pressure relief mechanism has a fourth surface facing away from the first hole segment, and the distance between the third surface and the fourth surface is H3, satisfying: H3 > 0.3 mm.

22. The battery cell of any one of claims 1-17, wherein, The wall portion has a third surface, and one end of the second hole segment away from the first hole segment extends to the third surface, with the hole wall surface of the second hole segment connected to the third surface; Along the thickness direction of the wall portion, the pressure relief mechanism includes a connecting portion disposed opposite to the third surface, the connecting portion being welded to the third surface.

23. The battery cell of any one of claims 1-22, wherein, The base material of the pressure relief mechanism is aluminum, and the thickness of the pressure relief mechanism along the thickness direction of the wall is H4, satisfying: 0.2mm≤H4≤0.8mm, optionally, 0.3mm≤H4≤0.6mm.

24. The battery cell of any one of claims 1-22, wherein, The base material of the pressure relief mechanism is iron, and the thickness of the pressure relief mechanism along the thickness direction of the wall is H4, satisfying: 0.1mm≤H4≤0.4mm, optionally, 0.15mm≤H4≤0.3mm.

25. The battery cell of any one of claims 1-24, wherein, Along the thickness direction of the wall portion, the size of the second hole segment is H5, satisfying: 0.25mm≤H5≤1.5mm, optionally, 0.3mm≤H5≤1mm.

26. The battery cell of any one of claims 1-25, wherein, Along the thickness direction of the wall portion, the size of the first hole segment is H6, satisfying: 0.2mm≤H6≤2mm, optionally, 0.3mm≤H6≤1.5mm.

27. The battery cell of any one of claims 1-26, wherein, The pressure relief mechanism is provided with a first groove, and the pressure relief mechanism is configured to split along at least a portion of the first groove when the pressure inside the housing reaches a threshold, so as to release the pressure, wherein the first groove is projected into the first hole segment along the thickness direction of the wall portion.

28. The battery cell of claim 27, wherein, Along the first direction, the minimum distance between the hole wall of the first hole segment and the first groove is L3, which satisfies: 1mm≤L3≤3mm, and the first direction is perpendicular to the thickness direction of the wall.

29. The battery cell of claim 28, wherein, The pressure relief mechanism is provided with a second groove, and the first groove is provided on the bottom surface of the second groove.

30. The battery cell of claim 29, wherein, The second groove is projected along the thickness direction of the wall portion and lies within the first hole segment.

31. The battery cell of claim 30, wherein, Along the first direction, the minimum distance between the hole wall of the first hole segment and the groove side of the second groove is L4, which satisfies: 0≤L4≤2mm, and optionally, 0.3mm≤L4≤1mm.

32. A battery device, wherein, Includes the battery cell according to any one of claims 1-31.

33. An electrical device, comprising: Includes a battery cell according to any one of claims 1-31, the battery cell being used to provide electrical energy to the electrical device.

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