Battery monomer, pressure relief mechanism, battery device and power utilization device

Abstract

The utility model provides a battery monomer, a pressure relief mechanism, a battery device and a power utilization device. The battery monomer comprises a shell, the shell is provided with a wall part, and the base material of the wall part is iron. The electrode assembly is housed within the housing. The base material of the pressure relief mechanism is iron, the pressure relief mechanism comprises a weak part, a body part and a connecting part, the weak part is configured to be damaged when the internal pressure of the shell reaches a threshold value, the body part is located in an area defined by the weak part, and the connecting part is located on the outer side of the weak part and connected to the wall part. The part, close to the weak part, in the body part is a first part, the part, close to the weak part, in the connecting part is a second part, and at least one of the first part and the second part extends relative to the weak part in the direction close to or away from the electrode assembly. At least one of the first part and the second part extends relative to the weak part, so that material flowing is facilitated when the weak part is punched and formed, the bursting pressure of a plurality of manufactured battery monomers is kept consistent, and the reliability of the battery monomers is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and more specifically, to a battery cell, a pressure relief mechanism, a battery device, and an electrical device. Background Art

[0002] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered. However, current battery reliability is relatively poor. Utility Model Content

[0003] The purpose of the embodiments of the present application is to provide a battery cell, a pressure relief mechanism, a battery device and an electrical device, which are intended to improve the problem of poor reliability of batteries in related technologies.

[0004] In the first aspect, an embodiment of the present application provides a battery cell, which includes a shell, an electrode assembly and a pressure relief mechanism, the shell having a wall portion, the base material of the wall portion being iron; the electrode assembly being accommodated in the shell; the base material of the pressure relief mechanism being iron, the pressure relief mechanism including a weak portion, a main body portion and a connecting portion, the weak portion being configured to be at least partially destroyed to release the pressure when the pressure inside the shell reaches a threshold value, the main body portion being located in an area surrounded by the weak portion, the connecting portion being located on the outside of the weak portion and connected to the wall portion, the portion of the main body portion close to the weak portion being a first portion, the portion of the connecting portion close to the weak portion being a second portion, and at least one of the first portion and the second portion extending relative to the weak portion in a direction approaching or away from the electrode assembly.

[0005] In the above technical solution, by extending at least one of the first and second portions relative to the weak portion in a direction toward or away from the electrode assembly, material flow is facilitated during stamping and forming of the weak portion, which helps improve stress in the weak portion. This results in a more stable structure in the formed weak portion, making it less likely to develop a concave or convex, wavy structure. This helps maintain consistent burst pressures across multiple battery cells during manufacture, thereby improving battery cell reliability. Furthermore, when a battery cell expands, the wall deforms under force, and at least one of the first and second portions extending relative to the weak portion can be stretched by external force. This reduces the pull of external forces on the weak portion, lowering the risk of premature damage to the weak portion and improving the lifespan and reliability of the battery cell.

[0006] As an optional technical solution of an embodiment of the present application, the difference between the surface roughness of the first part and the surface roughness of the weak part is less than or equal to Ra0.3, and / or the difference between the surface roughness of the second part and the surface roughness of the weak part is less than or equal to Ra0.3.

[0007] In the above technical solution, the surface roughness of the first part is basically consistent with the surface roughness of the weak part, and the surface roughness of the second part is basically consistent with the surface roughness of the weak part. In this way, the weak part can be stamped, and the roughness of the weak part is lower, so that the thickness consistency of different positions of the weak part is higher, which is more conducive to improving the consistency of the bursting pressure.

[0008] As an optional technical solution of an embodiment of the present application, the surface roughness of the weak portion, the surface roughness of the first portion, and the surface roughness of the second portion are the same.

[0009] In the above technical solution, the surface roughness of the first part is consistent with the surface roughness of the weak part, and the surface roughness of the second part is consistent with the surface roughness of the weak part. In this way, the weak part can be stamped, and the roughness of the weak part is lower, so that the thickness consistency of different positions of the weak part is higher, which is more conducive to improving the consistency of the bursting pressure.

[0010] As an optional technical solution of an embodiment of the present application, the pressure relief mechanism is provided with a pressure relief groove, the bottom wall of the pressure relief groove forms the weak portion; the groove side surface of the pressure relief groove and the groove bottom surface of the pressure relief groove are transitioned through rounded corners; and / or the pressure relief mechanism includes a first surface, the pressure relief groove is provided on the first surface, and the groove side surface of the pressure relief groove and the first surface are transitioned through rounded corners.

[0011] In the above technical solution, a weakened portion is formed on the pressure relief mechanism by providing a pressure relief groove. When the battery cell releases pressure, the pressure relief mechanism ruptures along at least a portion of the weakened portion. This is simple, convenient, and low-cost. The rounded transition between the side surfaces and bottom of the pressure relief groove helps reduce stress concentration and improves the consistency of the burst pressure. The rounded transition between the side surfaces and the first surface of the pressure relief groove helps reduce stress concentration and improves the consistency of the burst pressure.

[0012] As an optional technical solution of an embodiment of the present application, the material of the wall portion includes at least one of stainless steel and carbon steel; the material of the pressure relief mechanism includes at least one of stainless steel and carbon steel.

[0013] In the above technical solution, stainless steel and carbon steel have high strength, effectively improving the structural strength of the wall and pressure relief mechanism, reducing the risk of deformation due to stress, and thus reducing the risk of premature valve opening and pressure relief, thereby improving the service life and reliability of the battery cells. Furthermore, using at least one of stainless steel and carbon steel to manufacture the wall can appropriately reduce the wall thickness, which, while maintaining the same volume, helps increase the internal space of the housing, thereby increasing energy density.

[0014] As an optional technical solution of an embodiment of the present application, the material of the wall includes at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel; the material of the pressure relief mechanism includes at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel.

[0015] In the above technical solution, 304 stainless steel, 305 stainless steel and 316L stainless steel have the advantages of corrosion resistance, high temperature resistance and good processing performance. The wall and pressure relief mechanism made of 304 stainless steel, 305 stainless steel or 316L stainless steel have high strength, which can reduce the risk of deformation of the wall and the pressure relief mechanism due to force, which is beneficial to reducing the risk of the pressure relief mechanism opening the valve to relieve pressure prematurely, which is beneficial to improving the service life and reliability of the battery cell, and is beneficial to improving the consistency of the detonation pressure of multiple battery cells.

[0016] As an optional technical solution of an embodiment of the present application, the thickness of the main body is H1, satisfying: 0.05mm≤H1≤0.5mm; and / or the thickness of the connecting portion is H2, satisfying: 0.05mm≤H2≤0.5mm.

[0017] In the above technical solution, when H1 ≥ 0.05mm, the main body is thicker, providing greater structural strength, reducing the risk of deformation due to stress, and thus improving the battery cell's service life and reliability. When H1 ≤ 0.5mm, the main body is not excessively thick, helping to control the manufacturing cost of the battery cell. Therefore, when 0.05mm ≤ H1 ≤ 0.5mm, a balance between battery cell service life, reliability, and manufacturing cost is achieved.

[0018] When H2 ≥ 0.05mm, the thickness of the connection is greater, providing greater structural strength. This reduces the risk of deformation due to stress, thereby improving the battery cell's service life and reliability. When H2 ≤ 0.5mm, the thickness of the connection is not excessive, helping to control the manufacturing cost of the battery cell. Therefore, when 0.05mm ≤ H2 ≤ 0.5mm, the battery cell's service life, reliability, and manufacturing cost are balanced.

[0019] As an optional technical solution of an embodiment of the present application, the extension height of at least one of the first part and the second part relative to the weak portion is in the range of [0.2 mm, 7 mm].

[0020] In the above technical solution, when the extension height of at least one of the first part and the second part relative to the weak part is greater than or equal to 0.2mm, the extension height of at least one of the first part and the second part relative to the weak part is larger, which is convenient for material flow when the weak part is stamped and formed, and is beneficial to improving the stress of the weak part, so that the structural stability of the formed weak part is better. When the extension height of at least one of the first part and the second part relative to the weak part is less than or equal to 7mm, the extension height of at least one of the first part and the second part relative to the weak part is not too large. On the one hand, it is beneficial to reduce the occupation of the internal space of the battery device or battery cell and improve the energy density of the battery device or battery cell. On the other hand, it is beneficial to reduce the risk of interference with other components. Therefore, when the value range of the extension height of at least one of the first part and the second part relative to the weak part is [0.2mm, 7mm], it can take into account both the life and energy density of the battery cell and reduce the risk of interference with other components.

[0021] As an optional technical solution of an embodiment of the present application, the extension height of at least one of the first part and the second part relative to the weak portion is in the range of [0.3 mm, 5 mm].

[0022] In the above technical solution, when the extension height of at least one of the first part and the second part relative to the weak part is greater than or equal to 0.3mm, the extension height of at least one of the first part and the second part relative to the weak part is greater, which is convenient for material flow when stamping the weak part, and is beneficial to improving the stress of the weak part, so that the structural stability of the formed weak part is better. When the extension height of at least one of the first part and the second part relative to the weak part is less than or equal to 5mm, the extension height of at least one of the first part and the second part relative to the weak part is not too large. On the one hand, it is beneficial to reduce the occupation of the internal space of the battery device or battery cell and improve the energy density of the battery device or battery cell. On the other hand, it is beneficial to reduce the risk of interference with other components. Therefore, when the value range of the extension height of at least one of the first part and the second part relative to the weak part is [0.3mm, 5mm], it is better able to take into account the life and energy density of the battery cell and reduce the risk of interference with other components.

[0023] As an optional technical solution of an embodiment of the present application, the first portion at least partially extends relative to the weak portion in a direction approaching or away from the electrode assembly.

[0024] In the above technical solution, by extending the first portion at least partially in a direction toward or away from the electrode assembly relative to the weak portion, not only does this facilitate material flow during stamping and forming the weak portion, improving stress in the weak portion, but it also increases the contact area with internal gas, thereby facilitating pressure release through the weak portion. Thus, under the same burst pressure, the thickness of the weak portion can be increased. During normal use of the battery cell, the weak portion is less likely to prematurely rupture due to pressure changes within the battery cell or external impacts, thereby reducing the risk of premature damage to the weak portion and improving the lifespan of the battery cell. Compared to conventional aluminum explosion-proof valves, the pressure relief mechanism provided in the present embodiment has a smaller thickness of the weak portion. During manufacturing, even a slight change in the thickness of the weak portion can significantly change the burst pressure of the battery cell. By extending the first portion at least partially in a direction toward or away from the electrode assembly relative to the weak portion, the thickness of the weak portion can be increased under the same burst pressure. A thicker weak portion is easier to manufacture, thereby facilitating uniformity in the detonation pressure of multiple battery cells.

[0025] As an optional technical solution of an embodiment of the present application, the first portion entirely extends relative to the weak portion in a direction away from the electrode assembly.

[0026] In the above-mentioned technical solution, the existing pressure relief mechanism gradually arches from a flat plate structure away from the electrode assembly under the action of the internal pressure of the battery cell during pressure relief. After arching, it then opens to relieve pressure under the action of the internal pressure of the battery cell. In the embodiment of the present application, however, the first portion extends entirely in a direction away from the electrode assembly relative to the weak portion, forming a pre-deformation, thereby facilitating the rupture of the weak portion to release pressure. In this way, under the same burst pressure, the thickness of the weak portion can be greater. During normal use of the battery cell, the weak portion is less likely to rupture prematurely due to pressure changes within the battery cell or external impact, which helps reduce the risk of premature damage to the weak portion and improves the life of the battery cell. By having the first portion extend entirely in a direction away from the electrode assembly relative to the weak portion, when the battery cell releases pressure, the contact area between the main body and the internal gas is larger, and the external force applied to the first portion is greater. The first portion can directly pull on the weak portion, causing the weak portion to be subjected to greater shear force, thereby facilitating the opening of the weak portion to release pressure. Under the same burst pressure, the thickness of the weak portion can be greater. During normal use of the battery cell, the weak portion is less likely to crack prematurely due to pressure changes within the battery cell or external impact, which helps reduce the risk of premature damage to the weak portion and improve the life of the battery cell. In addition, a thicker weak portion is easier to manufacture, which helps to improve the consistency of the detonation pressure of multiple battery cells.

[0027] As an optional technical solution of an embodiment of the present application, a portion of the first portion extends relative to the weak portion in a direction away from the electrode assembly.

[0028] In the above-mentioned technical solution, the existing pressure relief mechanism gradually arches from a flat plate structure away from the electrode assembly during pressure relief under the action of the internal pressure of the battery cell. After arching, it then opens to release pressure under the action of the internal pressure of the battery cell. In the embodiment of the present application, a portion of the first portion extends relative to the weak portion in a direction away from the electrode assembly, forming a pre-deformation, thereby facilitating the rupture of the weak portion to release pressure. This allows for a greater thickness of the weak portion under the same burst pressure. During normal use of the battery cell, the weak portion is less likely to rupture prematurely due to pressure changes within the battery cell or external impacts, thereby reducing the risk of premature damage to the weak portion and improving the life of the battery cell. By extending a portion of the first portion relative to the weak portion in a direction away from the electrode assembly, the main body has a larger contact area with the internal gas during pressure relief, and the external force applied to the first portion is greater. The first portion can directly pull on the weak portion, causing the weak portion to be subjected to greater shear force, thereby facilitating the opening of the weak portion to release pressure. Under the same burst pressure, the thickness of the weak portion can be greater. During normal battery cell use, the weak portion is less likely to prematurely rupture due to pressure changes within the battery cell or external impact, thereby reducing the risk of premature damage to the weak portion and improving the lifespan of the battery cell. Furthermore, a thicker weak portion is easier to manufacture, thereby improving the consistency of the burst pressure across multiple battery cells. Furthermore, a portion of the first portion extending relative to the weak portion in a direction away from the electrode assembly facilitates controlling the extended height of the main portion.

[0029] As an optional technical solution of an embodiment of the present application, the electrode assembly includes at least two layers of electrode sheets; the at least two layers of electrode sheets are stacked, and the stacking direction of the at least two layers of electrode sheets is a first direction; or, the at least two layers of electrode sheets are wound, and the at least two layers of electrode sheets each include a planar segment located in the middle of the electrode assembly and a curved segment located at both ends of the electrode assembly, and the stacking direction of the at least two layers of electrode sheets in the planar segment is the first direction; the cross-section of the main body portion in at least one plane perpendicular to the first direction is arched.

[0030] In the above technical solution, by providing the main body with an arched cross-section in at least one plane perpendicular to the first direction, this, on the one hand, facilitates material flow during stamping and forming the weak portion, thereby improving stress in the weak portion and improving the structural stability of the formed weak portion. On the other hand, when the battery cell is depressurized, the main body has a larger contact area with the internal gas, and the external force applied to the main body is greater. The main body can better transmit the force to the weak portion, thereby pulling the weak portion, resulting in a greater shear force on the weak portion, and thus facilitating the opening and pressure relief of the weak portion. Under the same burst pressure, the thickness of the weak portion can be increased. During normal use of the battery cell, the weak portion is less likely to prematurely rupture due to pressure changes within the battery cell or external impact, thereby reducing the risk of premature damage to the weak portion and improving the life of the battery cell. Furthermore, when the battery cell expands, the arched shape is more easily stretched by external forces, thereby reducing the risk of external force being transmitted to the weak portion, further reducing the external force pulling on the weak portion and reducing the risk of premature damage to the weak portion, thereby improving the life of the battery cell.

[0031] As an optional technical solution of the embodiment of the present application, the extension height of the first part relative to the weak part is H3, which satisfies: 0.5mm≤H3≤5mm.

[0032] In the above technical solution, when H3 ≥ 0.5mm, the height of the first portion extending relative to the weak portion is higher. This results in more pronounced deformation of the main body. Under the same blasting pressure, the thickness of the weak portion is greater, which helps reduce the risk of premature damage to the weak portion and improves the life of the battery cell. When H3 ≤ 5mm, the height of the first portion extending relative to the weak portion is not too large. On the one hand, this helps reduce the internal space occupied by the battery device or battery cell and improves the energy density of the battery device or battery cell. On the other hand, it helps reduce the risk of interference between the main body and other components. Therefore, when 0.5mm ≤ H3 ≤ 5mm, it is possible to balance the life and energy density of the battery cell and reduce the risk of interference between the main body and other components.

[0033] As an optional technical solution of the embodiment of the present application, 0.8mm≤H3≤3mm.

[0034] In the above technical solution, when H3 ≥ 0.8mm, the height of the first portion extending relative to the weak portion is greater. This allows for more pronounced deformation of the main body. Under the same blasting pressure, the thickness of the weak portion is greater, which helps reduce the risk of premature damage to the weak portion and improves the lifespan of the battery cell. When H3 ≤ 3mm, the height of the first portion extending relative to the weak portion is not excessive. This, on the one hand, helps reduce the internal space occupied by the battery device or battery cell, thereby improving the energy density of the battery device or battery cell. On the other hand, it helps reduce the risk of interference between the main body and other components. Therefore, when 0.8mm ≤ H3 ≤ 3mm, it is possible to better balance the lifespan and energy density of the battery cell while reducing the risk of interference between the main body and other components.

[0035] As an optional technical solution of an embodiment of the present application, the second portion extends relative to the weak portion in a direction approaching or away from the electrode assembly.

[0036] In the above technical solution, by extending the second portion relative to the weak portion in a direction toward or away from the electrode assembly, on the one hand, it facilitates material flow during stamping and forming of the weak portion, which helps to improve the stress in the weak portion and improve the structural stability of the formed weak portion. On the other hand, when the battery cell expands, the second portion can be stretched by external force, thereby reducing the risk of external force being transmitted to the weak portion. This can further reduce the pulling of external forces on the weak portion, reduce the risk of premature damage to the weak portion, and help to extend the life of the battery cell.

[0037] As an optional technical solution of an embodiment of the present application, the connecting portion includes a third part, the third part is used to be connected to the wall portion, and the second part connects the weak portion and the third part.

[0038] In the above technical solution, the third part is used to connect with the wall portion, and the second wall portion connects the weak portion and the third part. During manufacturing, since the third part is farther away from the weak portion than the second part, the third part is not easily affected when processing the weak portion, so that the third part can maintain its original shape, thereby facilitating the connection of the third part with the wall portion.

[0039] As an optional technical solution of the embodiment of the present application, the third part is parallel to the wall portion.

[0040] In the above technical solution, by making the third part parallel to the wall, it is more convenient to connect the third part to the wall, which is beneficial to increase the stability of the connection between the third part and the wall.

[0041] As an optional technical solution of an embodiment of the present application, the second part is tilted relative to the third part, and the inclination angle of the second part relative to the third part is a, satisfying: 40°≤a≤75°.

[0042] In the above technical solution, when a ≥ 40°, the inclination of the connection is large, which effectively constrains the weak part and helps reduce the risk of creep failure of the weak part. When a ≤ 75°, the inclination of the connection is not too large, which helps reduce stress concentration and the risk of brittle fracture.

[0043] As an optional technical solution of an embodiment of the present application, both the first part and the second part extend relative to the weak portion, and the direction in which the first part extends relative to the weak portion is the same as the direction in which the second part extends relative to the weak portion.

[0044] In the above technical solution, when the first portion and the second portion extend in the same direction relative to the weak portion, the first portion can extend using the extended height of the second portion. This effectively reduces the height of the main portion above the surface of the connecting portion furthest from the electrode assembly, or reduces the height of the main portion above the surface of the connecting portion closest to the electrode assembly. This reduces the internal space occupied by the battery device or battery cell, thereby improving the energy density of the battery device or battery cell. Furthermore, when the battery cell is depressurized, the first and second portions exert opposite forces on the weak portion, subjecting the weak portion to shear forces and facilitating its opening and pressure relief. Under the same burst pressure, the thickness of the weak portion can be increased. During normal use of the battery cell, the weak portion is less likely to prematurely rupture due to internal pressure fluctuations or external impacts, thereby reducing the risk of premature damage to the weak portion and improving the life of the battery cell. Furthermore, when the battery cell expands, the first and second portions are more easily stretched by external forces, thereby reducing the risk of external forces being transmitted to the weak portion. This further reduces the pull of external forces on the weak portion, reducing the risk of premature damage to the weak portion and improving the life of the battery cell.

[0045] As an optional technical solution of an embodiment of the present application, both the first portion and the second portion extend relative to the weak portion in a direction close to the electrode assembly.

[0046] In the above technical solution, when both the first part and the second part extend relative to the weak part in a direction close to the electrode assembly, the first part can extend using the extended height of the second part, which is beneficial to reducing the height of the main body beyond the surface of the connecting part closest to the electrode assembly, reducing the occupation of the internal space of the battery cell, and beneficial to improving the energy density of the battery cell. In addition, when the battery cell is depressurized, the first part and the second part respectively apply forces in opposite directions to the weak part, so that the weak part is subjected to shear force, which facilitates the opening of the weak part to release pressure. Under the same blasting pressure, the thickness of the weak part can be larger. When the battery cell is in normal use, the weak part is not likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reducing the risk of premature damage to the weak part and improving the life of the battery cell.

[0047] As an optional technical solution of an embodiment of the present application, both the first portion and the second portion extend relative to the weak portion in a direction away from the electrode assembly.

[0048] In the above technical solution, when both the first part and the second part extend relative to the weak part in a direction away from the electrode assembly, the first part can extend using the extended height of the second part, which is beneficial to reducing the height of the main body beyond the surface of the connecting part farthest from the electrode assembly, reducing the space occupied by the internal battery, and improving the energy density of the battery device. In addition, when the battery cell is depressurized, the first part and the second part respectively apply forces in opposite directions to the weak part, so that the weak part is subjected to shear force, which facilitates the opening of the weak part to release pressure. Under the same blasting pressure, the thickness of the weak part can be larger. When the battery cell is in normal use, the weak part is not likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reducing the risk of premature damage to the weak part and improving the life of the battery cell.

[0049] As an optional technical solution of an embodiment of the present application, both the first part and the second part extend relative to the weak portion, and the direction in which the first part extends relative to the weak portion is opposite to the direction in which the second part extends relative to the weak portion.

[0050] In the above technical solution, by making the direction in which the first part extends relative to the weak portion opposite to the direction in which the second part extends relative to the weak portion, when the connecting portion is connected to the wall portion, it is not easy to affect the weak portion, which is beneficial to maintaining the performance of the weak portion and improving the life of the battery cell.

[0051] As an optional technical solution of an embodiment of the present application, the first portion extends relative to the weak portion in a direction close to the electrode assembly, and the second portion extends relative to the weak portion in a direction away from the electrode assembly.

[0052] In the above technical solution, by extending the first part relative to the weak part in the direction close to the electrode assembly and the second part relative to the weak part in the direction away from the electrode assembly, it is beneficial to reduce the occupation of the internal space of the battery, improve the energy density of the battery device, and reduce the risk of interference between the main body and other components in the battery.

[0053] As an optional technical solution of an embodiment of the present application, the first portion extends relative to the weak portion in a direction away from the electrode assembly, and the second portion extends relative to the weak portion in a direction close to the electrode assembly.

[0054] In the above technical solution, by extending the first part relative to the weak part in a direction away from the electrode assembly and the second part relative to the weak part in a direction close to the electrode assembly, it is beneficial to reduce the occupation of the internal space of the battery cell, improve the energy density of the battery cell, and reduce the risk of interference between the main body and other components in the battery cell.

[0055] As an optional technical solution of the embodiment of the present application, the minimum thickness of the weak portion is H4, satisfying 0.01mm≤H4≤0.2mm.

[0056] In the above technical solution, when H4 ≥ 0.01mm, the thickness of the weak portion is relatively large, making it less likely to crack prematurely due to pressure changes within the battery cell or external impacts. This helps reduce the risk of premature damage to the weak portion and improves the life of the battery cell. When H4 ≤ 0.2mm, the thickness of the weak portion is not too large, allowing the pressure relief mechanism to open and release pressure in a timely manner when the battery cell experiences thermal runaway, which helps improve the timeliness of the pressure relief mechanism's pressure relief. Therefore, when 0.01mm ≤ H4 ≤ 0.2mm, both the battery cell's lifespan and the timeliness of pressure relief can be taken into account.

[0057] As an optional technical solution of the embodiment of the present application, the projected area of ​​the main body along the thickness direction of the wall is S; wherein, 100mm 2 ≤450mm 2 , and 0.010mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H4≤0.190mm; or, 1550mm2 ≤S≤2100mm 2 , and 0.030mm≤H4≤0.200mm.

[0058] In the above technical solution, when the projected area of ​​the main body is larger, the main body is more susceptible to the internal pressure and the weak part is cracked. Therefore, when the projected area of ​​the main body is increased, in order to ensure the same bursting pressure, the thickness of the weak part can be increased. 2 ≤S≤450mm 2 , and when H4≥0.010mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤450mm 2 , and when H4≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤450mm 2 , and when 0.010mm≤H4≤0.160mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0059] When 350mm 2 ≤S≤850mm 2 When H4 is greater than or equal to 0.015mm, the thickness of the weak part is relatively large, and the weak part is not likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤850mm 2 , and when H4≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤850mm 2 , and when 0.015mm≤H4≤0.170mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0060] When 750mm 2 ≤S≤1250mm 2 When H4≥0.020mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤1250mm 2, and when H4≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤1250mm 2 , and when 0.020mm≤H4≤0.180mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0061] When 1150mm 2 ≤S≤1650mm 2 , and when H4≥0.025mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤1650mm 2 , and when H4≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.025mm≤H4≤0.190mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0062] When 1550mm 2 ≤S≤2100mm 2 When H4≥0.030mm, the thickness of the weak part is larger, and the weak part is not easy to crack prematurely due to pressure changes inside the battery cell or external impact, which is beneficial to reduce the risk of premature damage to the weak part and improve the life of the battery cell. 2 ≤S≤2100mm 2 , and when H4≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure in time when the battery cell is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.030mm≤H4≤0.200mm, both the service life of the battery cell and the timeliness of pressure relief can be taken into account.

[0063] As an optional technical solution of the embodiment of this application, 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2, and 0.025mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H4≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H4≤0.200mm.

[0064] In the above technical solution, when 100mm 2 ≤S≤450mm 2 , and when H4≥0.020mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤450mm 2 , and when H4≤0.160mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤450mm 2 , and when 0.020mm≤H4≤0.160mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0065] When 350mm 2 ≤S≤850mm 2 , and when H4≥0.025mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤850mm 2 , and when H4≤0.170mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤850mm 2 , and when 0.025mm≤H4≤0.170mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0066] When 750mm 2 ≤S≤1250mm 2, and when H4≥0.030mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤1250mm 2 , and when H4≤0.180mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤1250mm 2 , and when 0.030mm≤H4≤0.180mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0067] When 1150mm 2 ≤S≤1650mm 2 , and when H4≥0.035mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤1650mm 2 , and when H4≤0.190mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.035mm≤H4≤0.190mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0068] When 1550mm 2 ≤S≤2100mm 2 , and when H4≥0.040mm, the thickness of the weak part is greater, and the weak part is less likely to crack prematurely due to pressure changes inside the battery cell or external impact, which is more conducive to reducing the risk of premature damage to the weak part and improving the life of the battery cell. 2 ≤S≤2100mm 2 , and when H4≤0.200mm, the thickness of the weak part is not too large, so that the pressure relief mechanism can open and release pressure more promptly when the battery cell is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism. 2 ≤S≤2100mm 2 , and when 0.040mm≤H4≤0.200mm, it can better take into account the service life of the battery cell and the timeliness of pressure release.

[0069] As an optional technical solution of the embodiment of the present application, the connecting portion is welded to the wall portion.

[0070] In the above technical solution, the base materials of the pressure relief mechanism and the wall are both iron, and the connection part and the wall are easier to weld, which is beneficial to reduce the phenomenon of welding cracks between the pressure relief mechanism and the wall, thereby reducing the risk of leakage of the battery cell and improving the reliability of the battery cell.

[0071] As an optional technical solution of an embodiment of the present application, the battery cell also includes a support structure, which is fixed to the side of the wall facing the electrode assembly, the pressure relief mechanism is located on the side of the support structure away from the electrode assembly, the connecting portion is welded to the support structure, and the base material of the support structure is iron.

[0072] In the above technical solution, by providing a support structure, when welding the connection portion and the wall portion, the support structure can reduce the risk of the laser passing through the gap between the connection portion and the wall portion and acting on the electrode assembly, which is beneficial to improving the reliability of the battery cell. In addition, the support structure can play a positioning role in the process of fixed connection between the pressure relief mechanism and the wall portion. The support structure can also be used to achieve the connection and fixation between the pressure relief mechanism and the wall portion, both of which can effectively improve the processing efficiency of the battery cell. The support structure can also be used to support the pressure relief mechanism and the wall portion, increasing the structural strength and stability between the wall portion and the pressure relief mechanism. In particular, during the use of the battery cell, the battery cell will expand. The support structure can also be used to resist deformation, reduce cracking between the pressure relief mechanism and the wall portion caused by the expansion of the battery cell, and improve the stability of the battery cell.

[0073] As an optional technical solution of an embodiment of the present application, the support structure and the wall portion are fixed by welding or bonding.

[0074] In the above technical solution, when the support structure and the wall are fixed by welding, the connection strength between the support structure and the wall is relatively high. When the support structure and the wall are fixed by bonding, the connection between the support structure and the wall is relatively convenient, which is conducive to reducing production costs.

[0075] As an optional technical solution of an embodiment of the present application, along the direction approaching the electrode assembly, the pressure relief mechanism does not exceed the surface of the support structure facing the electrode assembly.

[0076] In the above technical solution, by ensuring that the pressure relief mechanism does not exceed the surface of the support structure facing the electrode assembly in the direction approaching the electrode assembly, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism and other components in the battery cell. On the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism being subjected to external forces exerted on the pressure relief mechanism by other components of the battery cell, making it less likely for the weak portion to crack prematurely, which is beneficial to reducing the risk of the weak portion being damaged prematurely and improving the life of the battery cell.

[0077] As an optional technical solution of the embodiment of the present application, the thickness of the support structure is H5, which satisfies: 0.4mm≤H5≤1.5mm.

[0078] In the above technical solution, when H5 ≥ 0.4mm, the thickness of the support structure is relatively large, and the laser during welding is not easy to penetrate the support structure, which can effectively reduce the risk of the laser passing through the gap between the connection part and the wall component and acting on the electrode assembly, which is beneficial to improving the reliability of the battery cell. When H5 ≤ 1.5mm, the thickness of the support structure is not too large. On the one hand, it can reduce the support structure's occupation of the internal space of the battery cell and improve the energy density of the battery cell. On the other hand, it can reduce the material consumption of the support structure and reduce the manufacturing cost of the battery cell. Therefore, when 0.4mm ≤ H5 ≤ 1.5mm, it can take into account the reliability, energy density and manufacturing cost of the battery cell.

[0079] As an optional technical solution of the embodiment of the present application, 0.4mm≤H5≤0.8mm.

[0080] In the above technical solution, when H5 ≥ 0.4mm, the thickness of the support structure is relatively large, and the laser during welding is not easy to penetrate the support structure, which can effectively reduce the risk of the laser passing through the gap between the connection part and the wall component and acting on the electrode assembly, which is beneficial to improving the reliability of the battery cell. When H5 ≤ 0.8mm, the thickness of the support structure is not too large. On the one hand, it can further reduce the support structure's occupation of the internal space of the battery cell and improve the energy density of the battery cell. On the other hand, it can further reduce the material consumption of the support structure and reduce the manufacturing cost of the battery cell. Therefore, when 0.4mm ≤ H5 ≤ 0.8mm, it can better take into account the reliability, energy density and manufacturing cost of the battery cell.

[0081] As an optional technical solution of an embodiment of the present application, the pressure relief mechanism, the wall portion and the support structure are connected by a same weld.

[0082] In the above technical solution, during welding, the pressure relief mechanism, the wall portion and the supporting structure can be welded together at one time, which makes the manufacturing simple and convenient.

[0083] As an optional technical solution of an embodiment of the present application, the battery cell also includes a separator, which is arranged on the side of the wall portion facing the electrode assembly. Along the direction approaching the electrode assembly, the pressure relief mechanism at least partially protrudes from the surface of the wall portion facing the electrode assembly, and the separator protrudes from the surface of the pressure relief mechanism facing the electrode assembly.

[0084] In the above technical solution, the pressure relief mechanism at least partially protrudes from the surface of the wall portion facing the electrode assembly in the direction close to the electrode assembly. By making the separator protrude from the surface of the pressure relief mechanism facing the electrode assembly in the direction close to the electrode assembly, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism and other components in the battery cell. On the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism being subjected to external force exerted on the pressure relief mechanism by other components of the battery cell, making it difficult for the weak portion to crack prematurely, which is beneficial to reducing the risk of the weak portion being damaged prematurely and improving the life of the battery cell.

[0085] As an optional technical solution of the embodiment of the present application, the partition includes a fourth part and a fifth part that are spaced apart, and the pressure relief mechanism is located between the fourth part and the fifth part.

[0086] In the above technical solution, the separator includes a fourth portion and a fifth portion spaced apart from each other. By positioning the pressure relief mechanism between the fourth and fifth portions, the fourth and fifth portions are less likely to interfere with the pressure relief mechanism's opening, allowing for timely pressure relief from the battery cells. Furthermore, during manufacturing, the fourth and fifth portions can be manufactured separately and then positioned on either side of the pressure relief mechanism, simplifying manufacturing and reducing assembly complexity.

[0087] As an optional technical solution of an embodiment of the present application, the partition is provided with an avoidance opening, and the avoidance opening is used to avoid the pressure relief mechanism.

[0088] In the above technical solution, the pressure relief mechanism is avoided by providing an avoidance opening, which is conducive to allowing the pressure relief mechanism to open and relieve pressure when the pressure inside the shell reaches a threshold.

[0089] As an optional technical solution of an embodiment of the present application, the partition is provided with a receiving groove opening toward the pressure relief mechanism, the receiving groove is used to accommodate the pressure relief mechanism, and the bottom of the receiving groove is provided with a thinning area corresponding to the pressure relief mechanism, and the thickness of the thinning area is less than the thickness of other areas of the bottom of the receiving groove.

[0090] In the above technical solution, the provision of a receiving groove to accommodate the pressure relief mechanism helps reduce the risk of interference between the pressure relief mechanism and other components within the battery cell. Furthermore, it helps reduce the risk of external forces exerted on the pressure relief mechanism by other components within the battery cell, making it less likely that the weak portion will crack prematurely, thereby reducing the risk of premature damage to the weak portion and improving the lifespan of the battery cell. By forming a thinned area at the bottom of the receiving groove, when the pressure within the housing reaches a threshold, the thinned area can open, allowing gas within the housing to flow to the pressure relief mechanism, thereby facilitating the opening of the pressure relief mechanism to release pressure.

[0091] As an optional technical solution of an embodiment of the present application, along the thickness direction of the wall portion, the pressure relief mechanism does not exceed the surface of the wall portion farthest from the electrode assembly in a direction away from the electrode assembly.

[0092] In the above technical solution, by ensuring that the pressure relief mechanism does not extend beyond the surface of the wall farthest from the electrode assembly along the thickness direction of the wall, this, on the one hand, reduces the space occupied by the battery interior, thereby improving the energy density of the battery device. On the other hand, the pressure relief mechanism is less likely to interfere with other components and be susceptible to external forces, thereby reducing the risk of premature damage to weak parts and improving the life of the battery cells.

[0093] As an optional technical solution of an embodiment of the present application, the battery cell also includes an electrode terminal, which is arranged on the wall portion, and the electrode terminal at least partially protrudes from the wall portion in a direction away from the electrode assembly; along the thickness direction of the wall portion, the pressure relief mechanism does not exceed the surface of the electrode terminal farthest from the electrode assembly in a direction away from the electrode assembly.

[0094] In the above technical solution, by ensuring that the pressure relief mechanism does not extend beyond the surface of the electrode terminal farthest from the electrode assembly along the thickness direction of the wall, this, on the one hand, reduces the space occupied by the battery interior, thereby improving the energy density of the battery device. On the other hand, the pressure relief mechanism is less likely to interfere with other components and be susceptible to external forces, thereby reducing the risk of premature damage to weak parts and improving the life of the battery cells.

[0095] As an optional technical solution of the embodiment of the present application, the weak portion is in the form of a closed ring, and the thickness of each portion of the weak portion is the same.

[0096] In the above technical solution, by making the weak portion into a closed ring shape and having equal thickness at all locations, when the pressure inside the shell reaches a threshold value, the pressure relief mechanism can split along the entire circumference of the weak portion, so that the main body can be separated from the pressure relief mechanism. The main body is not easy to hang on the second part and is not easy to block the gas eruption, which reduces the risk of spraying high-temperature gas to adjacent battery cells and is beneficial to improving the reliability of the battery cells.

[0097] As an optional technical solution of an embodiment of the present application, the weak portion is in a closed ring shape, and the weak portion includes a first weak section and a second weak section connected end to end, the thickness of the second weak section is greater than the thickness of the first weak section, and the second weak section is located on one side of the weak portion in the length direction of the wall portion.

[0098] In the above technical solution, by providing a second weak section, the strength of the pressure relief mechanism at the second weak section is weakened, making it easier for the main body to flip open under the influence of the internal gas pressure of the battery cell. This not only increases the probability of the main body opening, but also increases the speed of the main body opening, achieving rapid pressure relief, reducing the risk of battery cell explosion and fire, and thus improving the reliability of the battery cell. By locating the second weak section to one side of the weak portion along the length of the wall, when the battery cell pressure is released, even if the main body is not fully opened, the ejected high-temperature gas will diffuse along the length of the wall under the influence of the main body. In other words, the ejected high-temperature gas is less likely to be directed toward another adjacent battery cell, thereby less likely to cause thermal runaway in the other battery cell, thus improving the reliability of the battery device.

[0099] As an optional technical solution of the embodiment of the present application, the weak portion is open-shaped, and the open end of the weak portion is located on one side of the weak portion in the length direction of the wall portion.

[0100] In the above technical solution, by locating the open end of the weak portion on one side of the weak portion in the longitudinal direction of the wall portion, when the battery cell is depressurized, even if the main body portion is not fully opened, the ejected high-temperature gas will diffuse toward the longitudinal direction of the wall portion under the action of the main body portion. That is, the ejected high-temperature gas is not likely to be directed toward another adjacent battery cell, and is not likely to cause thermal runaway of another battery cell, which is beneficial to improving the reliability of the battery device.

[0101] As an optional technical solution of the embodiment of the present application, the pressure relief mechanism is provided with a pressure relief groove, and the bottom wall of the pressure relief groove forms the weak portion.

[0102] In the above technical solution, a weak portion is formed on the pressure relief mechanism by providing a pressure relief groove on the pressure relief mechanism. When the battery cell releases pressure, the pressure relief mechanism is cracked along at least a portion of the weak portion, which is simple, convenient and low-cost.

[0103] As an optional technical solution of an embodiment of the present application, the pressure relief groove is formed by stamping.

[0104] In the above technical solution, the pressure relief groove is formed by stamping, which makes it easier to control the thickness of the weak part and has higher processing accuracy, which is beneficial to keep the bursting pressure of multiple battery cells consistent when manufacturing multiple battery cells, and is beneficial to improving the reliability of the battery cells.

[0105] As an optional technical solution of the embodiment of the present application, the cross-section of the pressure relief groove is trapezoidal or conical.

[0106] In the above technical solution, when the cross-section of the pressure relief groove is trapezoidal or conical, it is beneficial for the main body to quickly open and release pressure when the battery cell experiences thermal runaway.

[0107] As an optional technical solution of an embodiment of the present application, along the width direction of the pressure relief groove, the pressure relief groove includes two groove side surfaces arranged opposite to each other, and the angle between the two groove side surfaces is b, satisfying: 30°≤b≤90°, optionally, 40°≤b≤80°.

[0108] In the above technical solution, when b ≥ 30°, the pressure relief groove can be easily punched out, reducing the processing difficulty of the pressure relief groove and thus reducing the manufacturing cost of the battery cell. When b ≤ 90°, it can reduce material extrusion. Therefore, when 30° ≤ b ≤ 90°, it can reduce both the manufacturing cost of the battery cell and the extrusion of material.

[0109] When b ≥ 40°, the pressure relief groove can be punched out more easily, reducing the difficulty of processing the pressure relief groove, thereby further reducing the manufacturing cost of the battery cell. When b ≤ 80°, it can further reduce material extrusion. Therefore, when 40° ≤ b ≤ 80°, it can reduce both the manufacturing cost of the battery cell and the extrusion of material.

[0110] In the second aspect, an embodiment of the present application further provides a pressure relief mechanism, which is used for a battery cell. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion, a main body portion and a connecting portion. The weak portion is configured to be at least partially destroyed to release the pressure when the pressure inside the battery cell reaches a threshold value. The main body portion is located in the area surrounded by the weak portion, and the connecting portion is located on the outside of the weak portion. The portion of the main body portion close to the weak portion is the first portion, and the portion of the connecting portion close to the weak portion is the second portion. At least one of the first portion and the second portion extends relative to the weak portion along the thickness direction of the pressure relief mechanism.

[0111] In a third aspect, an embodiment of the present application further provides a method for manufacturing a pressure relief mechanism, which is used for a battery cell, and the method for manufacturing the pressure relief mechanism includes: step S100: providing a sheet, the base material of which is iron; step S200: processing a weak portion on the sheet, the weak portion being used to be at least partially destroyed to release the pressure when the pressure inside the battery cell reaches a threshold value, the portion of the sheet located within the area surrounded by the weak portion is the main body, and the portion of the sheet located outside the area surrounded by the weak portion is the connecting portion; wherein, the portion of the main body close to the weak portion is the first portion, and the portion of the connecting portion close to the weak portion is the second portion, and at least one of the first portion and the second portion extends relative to the weak portion along the thickness direction of the sheet.

[0112] As an optional technical solution of an embodiment of the present application, before step S200, the pressure relief mechanism manufacturing method also includes: step S150: punching the sheet to form a groove on the sheet; step S200 includes: step S210: processing the weak portion on the bottom wall of the groove so that the second portion extends relative to the weak portion along the thickness direction of the sheet.

[0113] In the above technical solution, by first machining a groove on the sheet and then machining a weak portion on the bottom surface of the groove, the second portion can be extended relative to the weak portion along the thickness direction of the sheet, which is simple and convenient.

[0114] As an optional technical solution of the embodiment of the present application, the step S200 includes: step S220: punching the sheet to form the weak portion on the sheet.

[0115] In the above technical solution, the weak part is processed by stamping, which makes it easier to control the thickness of the weak part and has higher processing accuracy, which is beneficial to keep the bursting pressure of multiple battery cells consistent when manufacturing multiple battery cells, and is beneficial to improving the reliability of the battery cells.

[0116] As an optional technical solution of an embodiment of the present application, in step S220, the flow direction of the sheet is controlled so that the first portion extends relative to the weak portion along the thickness direction of the sheet.

[0117] In the above technical solution, by controlling the flow direction of the sheet when stamping the weak portion, the first portion can be extended relative to the weak portion along the thickness direction of the sheet, which is simple and convenient.

[0118] In a fourth aspect, an embodiment of the present application further provides a battery device, which includes the above-mentioned battery cell.

[0119] In a fifth aspect, an embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell, and the battery cell is used to provide electrical energy to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0121] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0122] Figure 2 An exploded view of a battery device provided in some embodiments of the present application;

[0123] Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0124] Figure 4 An exploded view of a battery cell provided in some embodiments of the present application;

[0125] Figure 5 A schematic structural diagram of a pressure relief mechanism provided in some embodiments of the present application;

[0126] Figure 6 A schematic top view of a pressure relief mechanism provided in some embodiments of the present application;

[0127] Figure 7 for Figure 6 Cross-sectional view at the AA position;

[0128] Figure 8 for Figure 7 A magnified view of position B in the middle;

[0129] Figure 9 Cross-sectional views of pressure relief mechanisms provided in other embodiments of the present application;

[0130] Figure 10 A schematic top view of a pressure relief mechanism provided in some other embodiments of the present application;

[0131] Figure 11 for Figure 10 Cross-sectional view at the mid-CC position;

[0132] Figure 12 A schematic top view of a pressure relief mechanism provided in some further embodiments of the present application;

[0133] Figure 13 for Figure 12 Cross-sectional view at the middle DD position;

[0134] Figure 14 A cross-sectional view of a pressure relief mechanism provided in some embodiments of the present application;

[0135] Figure 15 A cross-sectional view of a pressure relief mechanism provided in some other embodiments of the present application;

[0136] Figure 16 A cross-sectional view of a pressure relief mechanism provided in some other embodiments of the present application;

[0137] Figure 17 A schematic diagram of the connection between the pressure relief mechanism, the wall portion, and the support structure provided in some embodiments of the present application;

[0138] Figure 18 A schematic diagram of the connection between the pressure relief mechanism, the wall portion, the support structure, and the partition provided in some embodiments of the present application;

[0139] Figure 19 A schematic structural diagram of a separator provided in some embodiments of the present application;

[0140] Figure 20 A schematic structural diagram of a separator provided in some other embodiments of the present application;

[0141] Figure 21 Cross-sectional views of separators provided in some other embodiments of the present application;

[0142] Figure 22 A cross-sectional view of a separator provided in some further embodiments of the present application;

[0143] Figure 23 A schematic diagram of a structure in which electrode terminals are provided on a wall portion provided in some embodiments of the present application;

[0144] Figure 24 A schematic top view of a pressure relief mechanism provided in yet other embodiments of the present application;

[0145] Figure 25 for Figure 24 Cross-sectional view at the EE position;

[0146] Figure 26 A schematic top view of a pressure relief mechanism provided in some other embodiments of the present application;

[0147] Figure 27 A schematic block diagram of a method for manufacturing a pressure relief mechanism provided in some embodiments of the present application;

[0148] Figure 28 A schematic block diagram of a method for manufacturing a pressure relief mechanism provided in some other embodiments of the present application;

[0149] Figure 29 A schematic block diagram of a method for manufacturing a pressure relief mechanism provided in some further embodiments of the present application.

[0150] Icons: 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-shell; 212-end cover; 213-wall; 2131-pressure relief hole; 23-electrode assembly; 231-main body; 232-ear; 24-pressure relief mechanism; 241-connecting part; 2411-second part; 2412-third part; 2421-weak part; 24212-first weak section; 24213-second weak section; 24212a-first section; 24212b-second section; 24212c-third section; 2422-main body; 24221-first part; 245-pressure relief groove; 2451-bottom surface of the groove; 2452-side surface of the groove; 2453-rounded corner; 246-first surface; 25-electrode terminal; 26-protective member; 27-insulating member; 28-support structure; 281-weld; 29-partition; 291-fourth part; 292-fifth part; 293-avoidance opening; 294-accommodating groove; 2941-thinning area; 30-pressure relief mechanism manufacturing method; 100-battery device; 200-controller; 300-motor; 1000-vehicle. DETAILED DESCRIPTION

[0151] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0152] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0153] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0154] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0155] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0156] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0157] The term "plurality" used in this application refers to two or more (including two).

[0158] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0159] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0160] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits to a certain extent while allowing the active ions to pass through.

[0161] 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.

[0162] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0163] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, 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. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may 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.).

[0164] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides 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, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0165] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0166] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0167] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may 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.).

[0168] 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.

[0169] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0170] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. 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, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0171] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0172] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0173] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0174] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0175] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0176] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0177] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0178] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0179] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0180] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0181] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0182] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0183] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0184] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0185] In some embodiments, the electrode assembly is a laminate structure.

[0186] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0187] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0188] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0189] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0190] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0191] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0192] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0193] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0194] In some embodiments, the housing can be a sealed structure or a non-sealed structure. For example, when the housing is a sealed structure, the housing can protect the electrode assembly and, to a certain extent, prevent leakage of the electrolyte. When the housing is a non-sealed structure, the housing can also protect the electrode assembly. A sealing bag can be included between the housing and the electrode assembly to encapsulate the electrode assembly and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film.

[0195] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include but are not limited to square-shell, blade-shaped, and polygonal batteries, such as hexagonal batteries.

[0196] The battery device mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0197] In some embodiments, the battery device may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0198] In some embodiments, the battery device may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0199] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0200] In some embodiments, the battery device may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0201] Currently, market developments indicate that batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0202] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as energy density, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered. However, current battery reliability is relatively poor.

[0203] For battery cells, in order to improve the reliability of battery cells, the existing technology is to set a pressure relief mechanism on the battery cells. A weak part is set on the pressure relief mechanism. When the internal pressure of the battery cell reaches the bursting pressure, the weak part cracks to release the pressure inside the battery cell, thereby reducing the risk of battery cell explosion and fire.

[0204] However, at present, when manufacturing multiple battery cells, the bursting pressures of multiple battery cells vary greatly. The weak parts of some battery cells have already cracked before the internal pressure reaches the bursting pressure, and the weak parts of some battery cells have not cracked after the internal pressure exceeds the bursting pressure, which increases the risk of battery cell explosion and fire, resulting in poor reliability of the battery cells.

[0205] In view of this, an embodiment of the present application provides a battery cell, which includes a shell, an electrode assembly and a pressure relief mechanism. The shell has a wall portion, the base material of the wall portion is iron, and the electrode assembly is accommodated in the shell. The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion, a main body portion and a connecting portion. The weak portion is configured to be at least partially destroyed to release pressure when the pressure inside the shell reaches a threshold value. The main body portion is located in the area surrounded by the weak portion, and the connecting portion is located on the outside of the weak portion and is connected to the wall portion. The portion of the main body portion close to the weak portion is the first portion, and the portion of the connecting portion close to the weak portion is the second portion. At least one of the first portion and the second portion extends relative to the weak portion in a direction close to or away from the electrode assembly.

[0206] By extending at least one of the first and second portions relative to the weak portion in a direction toward or away from the electrode assembly, material flow is facilitated during stamping and forming of the weak portion, which helps improve stress in the weak portion. This results in a more stable structure in the formed weak portion, making it less likely to develop a concave or convex, wavy structure. This helps maintain consistent burst pressures across multiple battery cells during manufacture, thereby improving battery cell reliability. Furthermore, when a battery cell expands, the wall deforms under force, and at least one of the first and second portions extending relative to the weak portion can be stretched by external forces. This reduces the pull of external forces on the weak portion, lowering the risk of premature damage to the weak portion and improving the lifespan and reliability of the battery cell.

[0207] The technical solutions described in the embodiments of the present application are applicable to battery devices and electrical devices using battery devices.

[0208] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and power tools. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, and may include but are not limited to electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0209] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0210] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000. The battery device 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000. For example, the battery device 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0211] In some embodiments of the present application, the battery device 100 can serve not only as an operating power source for the vehicle 1000 , but also as a driving power source for the vehicle 1000 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000 .

[0212] Please refer to Figure 2 , Figure 2 The exploded view of the battery device 100 provided in some embodiments of the present application. The battery device 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide a storage space for the battery cell 20, and the case 10 can adopt a variety of structures. In some embodiments, the case 10 may include a first box body 11 and a second box body 12, and the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define a storage space for accommodating the battery cell 20. The second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-shaped structure. The first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define a storage space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0213] In the battery device 100, there may be multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery unit 20 may be housed within the housing 10. Alternatively, the battery device 100 may comprise multiple battery cells 20 connected in series, in parallel, or in a hybrid connection to form a battery module, which is then further connected in series, in parallel, or in a hybrid connection to form a single unit and housed within the housing 10. The battery device 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0214] Each battery cell 20 may be a secondary battery cell or a primary battery cell; it may also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0215] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 , Figure 3 This is a schematic structural diagram of a battery cell 20 provided in some embodiments of the present application. Figure 4 An exploded view of a battery cell 20 provided in some embodiments of the present application. Figure 5 This is a schematic structural diagram of the pressure relief mechanism 24 provided in some embodiments of the present application. Figure 6 Schematic top view of the pressure relief mechanism 24 provided in some embodiments of the present application. Figure 7 for Figure 6 Cross-sectional view at position AA. Figure 8 for Figure 7 An enlarged view of position B in the middle. An embodiment of the present application provides a battery cell 20, which includes a shell 21, an electrode assembly 23 and a pressure relief mechanism 24. The shell 21 has a wall portion 213, the base material of the wall portion 213 is iron, and the electrode assembly 23 is accommodated in the shell 21. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak portion 2421, a main body portion 2422 and a connecting portion 241. The weak portion 2421 is configured to be at least partially destroyed to release pressure when the pressure inside the shell 21 reaches a threshold value. The main body portion 2422 is located in the area enclosed by the weak portion 2421, and the connecting portion 241 is located on the outside of the weak portion 2421 and is connected to the wall portion 213. The portion of the main body 2422 close to the weak portion 2421 is the first portion 24221, and the portion of the connecting portion 241 close to the weak portion 2421 is the second portion 2411. At least one of the first portion 24221 and the second portion 2411 extends relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23.

[0216] The battery cell 20 refers to the smallest unit constituting the battery device 100 .

[0217] The housing 21 includes a shell 211 and an end cap 212. The shell 211 has an accommodation space with one end open, and the accommodation space is used to accommodate the electrode assembly 23. The end cap 212 is connected to the shell 211 and closes the opening.

[0218] The end cap 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the shell 211 to match the shell 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as an aluminum alloy). In this way, the end cap 212 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and improved reliability. The material of the end cap 212 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The end cap 212 is also provided with an electrode terminal 25, which is used to electrically connect to the tab 232 of the electrode assembly 23 to input or output electrical energy of the battery cell 20. The electrode terminal 25 and the tab 232 can be directly connected, for example, the electrode terminal 25 and the tab 232 are directly welded. The electrode terminal 25 and the tab 232 can also be indirectly connected, for example, through a current collecting member. The battery cell 20 also includes an insulator 27, which is disposed inside the end cap 212. The insulator 27 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. Exemplary materials include plastic, rubber, and the like.

[0219] The housing 211 is a component that cooperates with the end cap 212 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 211 and end cap 212 can be separate components. An opening can be provided in the housing 211, and the end cap 212 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 212 and housing 211 can be integrated. Specifically, the end cap 212 and housing 211 can form a common joint surface before other components are inserted into the housing. When the interior of the housing 211 needs to be enclosed, the end cap 212 is placed over the housing 211. The housing 211 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 211 can be determined based on 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.

[0220] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be contained in the housing 211. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets with active materials constitute the main body 231 of the electrode assembly 23, and the portions of the positive and negative electrode sheets without active materials each constitute a tab 232. The positive tab and the negative tab may be located together at one end of the main body 231 or respectively at both ends of the main body 231. During the charge and discharge process of the battery cell 20, the positive active material and the negative active material react with the electrolyte.

[0221] The wall portion 213 may be the end cover 212 of the housing 21 or a wall of the shell 211 of the housing 21. Figure 3 and Figure 4 In the embodiment, the wall portion 213 is the end cap 212. In other embodiments, the wall portion 213 is the bottom wall of the housing 211 opposite to the end cap 212. In still other embodiments, the wall portion 213 may also be a side wall of the housing 211 adjacent to and connected to the end cap 212.

[0222] “The base material of the wall portion 213 is iron” means that iron is the largest material by mass in the material of the wall portion 213. For example, the material of the wall portion 213 can be carbon steel or stainless steel.

[0223] The pressure relief mechanism 24 is a component designed to release the internal pressure of the battery cell 20 when the internal pressure or temperature reaches the burst pressure. The pressure relief mechanism 24 is mounted on the wall portion 213. The pressure relief mechanism 24 is separate from and connected to the wall portion 213. During manufacturing, a pressure relief hole 2131 is formed in the wall portion 213. The pressure relief mechanism 24 and the wall portion 213 are provided separately and then connected together so that the pressure relief mechanism 24 covers the pressure relief hole 2131. For example, the pressure relief mechanism 24 can be welded to the wall portion 213. The pressure relief mechanism 24 can be a burst disk mounted on the wall portion 213. The location of the pressure relief mechanism 24 can be used to identify which wall of the housing 21 is the wall portion 213. For example, if the pressure relief mechanism 24 is mounted on the end cap 212, the end cap 212 is the wall portion 213. If the pressure relief mechanism 24 is mounted on the bottom wall of the housing 211, the bottom wall is the wall portion 213. When the pressure relief mechanism 24 is disposed on a side wall of the housing 211 , the side wall serves as the wall portion 213 .

[0224] "The base material of the pressure relief mechanism 24 is iron" means that the material with the largest mass percentage in the material of the pressure relief mechanism 24 is iron. For example, the material of the pressure relief mechanism 24 can be carbon steel or stainless steel.

[0225] The weak portion 2421 serves as a pressure relief mechanism, allowing the pressure relief mechanism 24 to rupture along at least a portion of the weak portion 2421 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, thereby releasing the pressure within the battery cell 20. In some embodiments, the strength of the pressure relief mechanism 24 at the weak portion 2421 can be lower than the strength of the pressure relief mechanism 24 at other locations. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the weak portion 2421 can rupture under the action of the internal pressure, thereby releasing the pressure within the battery cell 20. In other embodiments, the melting point of the pressure relief mechanism 24 at the weak portion 2421 can be lower than the melting point of the pressure relief mechanism 24 at other locations. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the weak portion 2421 can rupture under the action of high temperature, thereby releasing the pressure within the battery cell 20.

[0226] The weak portion 2421 may be an annular structure, for example, a circular ring or an elliptical ring. The weak portion 2421 may also be a non-annular structure, for example, a C-shape or a U-shape.

[0227] The main body 2422 is the portion of the pressure relief mechanism 24 located within the area enclosed by the weak portion 2421. The connecting portion 241 is the portion of the pressure relief mechanism 24 located outside the area enclosed by the weak portion 2421, and the connecting portion 241 is used to connect to the wall portion 213. The area enclosed by the weak portion 2421 is the area where the pressure relief mechanism 24 forms an opening after the weak portion 2421 is destroyed by the gas inside the housing 21. If the weak portion 2421 has an annular structure, the area enclosed by the weak portion 2421 is the area within the annular structure. If the weak portion 2421 has a non-annular structure, the area enclosed by the weak portion 2421 is the area inside the annular structure formed by the weak portion 2421 itself and the line connecting the two ends of the weak portion 2421.

[0228] The first portion 24221 is a portion of the main body 2422 close to the weak portion 2421 . In other words, a boundary of the first portion 24221 overlaps with an inner boundary of the weak portion 2421 .

[0229] The second portion 2411 is a portion of the connecting portion 241 close to the weak portion 2421 . In other words, a boundary of the second portion 2411 overlaps with an outer boundary of the weak portion 2421 .

[0230] Please refer to Figure 4 and Figure 7 The thickness direction of the wall portion 213 is the X direction shown in the figure. In the figure, the downward direction along the thickness direction of the wall portion 213 is the direction close to the electrode assembly 23, and the upward direction along the thickness direction of the wall portion 213 is the direction away from the electrode assembly 23.

[0231] “At least one of the first portion 24221 and the second portion 2411 extends relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23” includes: only the first portion 24221 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23, only the first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23, only the second portion 2411 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23, only the second portion 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 and the second portion 2421 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 and the second portion 2421 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23. 11 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23, the first portion 24221 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 and the second portion 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 and the second portion 2411 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23, and the first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 and the second portion 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23.

[0232] By extending at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 in a direction toward or away from the electrode assembly 23, material flow is facilitated during stamping and forming of the weak portion 2421, which helps improve the stress in the weak portion 2421. This ensures that the formed weak portion 2421 has greater structural stability and is less likely to develop a concave and convex wavy structure. This helps maintain consistent burst pressures across multiple battery cells 20 during manufacture, thereby improving the reliability of the battery cells 20. Furthermore, when the battery cell 20 expands, the wall portion 213 deforms under force, and at least one of the first portion 24221 and the second portion 2411 extending relative to the weak portion 2421 can be stretched by external force. This reduces the pulling of the weak portion 2421 by external forces, lowering the risk of premature damage to the weak portion 2421 and improving the lifespan and reliability of the battery cell 20.

[0233] In some embodiments, the difference between the surface roughness of the first portion 24221 and the surface roughness of the weak portion 2421 is less than or equal to Ra0.3, and / or the difference between the surface roughness of the second portion 2411 and the surface roughness of the weak portion 2421 is less than or equal to Ra0.3.

[0234] Surface roughness refers to the unevenness of a machined surface, characterized by small peaks and valleys. The distance between two peaks or valleys (wave pitch) is very small (less than 1 mm), and it is considered a microscopic geometric error. The smaller the surface roughness, the smoother the surface.

[0235] The difference between the surface roughness of the first portion 24221 and the surface roughness of the weak portion 2421 is less than or equal to Ra0.3, that is, the surface roughness of the first portion 24221 and the surface roughness of the weak portion 2421 are substantially the same.

[0236] The difference between the surface roughness of the second portion 2411 and the surface roughness of the weak portion 2421 is less than or equal to Ra0.3, that is, the surface roughness of the second portion 2411 and the surface roughness of the weak portion 2421 are substantially the same.

[0237] The surface roughness of the first part 24221 is basically consistent with the surface roughness of the weak part 2421, and the surface roughness of the second part 2411 is basically consistent with the surface roughness of the weak part 2421. In this way, the weak part 2421 can be stamped, and the roughness of the weak part 2421 is lower, so that the thickness consistency of different positions of the weak part 2421 is higher, which is more conducive to improving the consistency of the bursting pressure.

[0238] Optionally, the surface roughness of the weak portion 2421 , the surface roughness of the first portion 24221 , and the surface roughness of the second portion 2411 are the same.

[0239] The surface roughness of the first part 24221 is consistent with the surface roughness of the weak part 2421, and the surface roughness of the second part 2411 is consistent with the surface roughness of the weak part 2421. In this way, the weak part 2421 can be stamped, and the roughness of the weak part 2421 is lower, so that the thickness consistency of different positions of the weak part 2421 is higher, which is more conducive to improving the consistency of the bursting pressure.

[0240] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245, the bottom wall of which forms a weak portion 2421. A groove side surface 2452 of the pressure relief groove 245 transitions to a groove bottom surface 2451 of the pressure relief groove 245 via a rounded corner 2453. Alternatively, the pressure relief mechanism 24 includes a first surface 246, the pressure relief groove 245 is provided on the first surface 246, and a groove side surface 2452 of the pressure relief groove 245 transitions to the first surface 246 via a rounded corner 2453.

[0241] The pressure relief mechanism 24 has a first surface 246 and a second surface disposed opposite each other in the thickness direction of the wall portion 213. One of the first surface 246 and the second surface faces the electrode assembly 23, while the other faces away from the electrode assembly 23. A pressure relief groove 245 is disposed on the first surface 246, i.e., the pressure relief groove 245 is recessed from the first surface 246 toward the second surface. The weak portion 2421 is the portion between the bottom surface 2451 of the pressure relief groove 245 and the second surface.

[0242] The pressure relief groove 245 can be formed by various methods, such as stamping, cold heading, etc. Taking stamping as an example, the pressure relief groove 245 can be stamped on the pressure relief mechanism 24 along the thickness direction of the wall portion 213 to form the pressure relief groove 245 .

[0243] Stamping or cold-forging the pressure relief groove 245 causes the groove wall of the pressure relief groove 245 to undergo cold work hardening (changing the grain arrangement, causing lattice distortion, reducing the metal's plasticity, and increasing the material's hardness). This enhances its ability to resist external impact and makes it less susceptible to damage from external impact. This helps reduce the risk of leakage from the pressure relief mechanism 24.

[0244] The groove side surface 2452 of the pressure relief groove 245 and the groove bottom surface 2451 of the pressure relief groove 245 are transitioned with rounded corners, so that the groove side surface 2452 of the pressure relief groove 245 and the groove bottom surface 2451 of the pressure relief groove 245 have a smooth transition.

[0245] The groove side surface 2452 of the pressure relief groove 245 and the first surface 246 have rounded corners for transition, so that the groove side surface 2452 and the first surface 246 of the pressure relief groove 245 have a smooth transition.

[0246] By providing a pressure relief groove 245 on the pressure relief mechanism 24 to form a weak portion 2421, the pressure relief mechanism 24 ruptures along at least a portion of the weak portion 2421 when the battery cell 20 releases pressure. This is simple, convenient, and low-cost. By transitioning between the side surface 2452 of the pressure relief groove 245 and the bottom surface 2451 of the pressure relief groove 245 via a rounded corner 2453, stress concentration is reduced and the consistency of the burst pressure is improved. By transitioning between the side surface 2452 of the pressure relief groove 245 and the first surface 246 via a rounded corner 2453, stress concentration is reduced and the consistency of the burst pressure is improved.

[0247] In some embodiments, the material of the wall portion 213 includes at least one of stainless steel and carbon steel. The material of the pressure relief mechanism 24 includes at least one of stainless steel and carbon steel.

[0248] The material of the wall portion 213 may be carbon steel or stainless steel, etc. The carbon steel may be low carbon steel, medium carbon steel or high carbon steel.

[0249] It should be noted that the material of the wall portion 213 includes at least one of stainless steel and carbon steel. If the wall portion 213 is the end cover 212 of the outer shell 21, the material of the end cover 212 includes at least one of stainless steel and carbon steel; if the wall portion 213 is a wall in the shell 211, the material of the shell 211 includes at least one of stainless steel and carbon steel.

[0250] In this embodiment, the material of the wall portion 213 is set to include at least one of stainless steel and carbon steel. Since steel has the characteristic of high strength, the wall portion 213 made of steel has better strength. When the bursting pressure of the battery cell 20 is constant, the wall portion 213 can be made thinner, which is beneficial to saving the space occupied by the wall portion 213.

[0251] The material of the pressure relief mechanism 24 can be carbon steel or stainless steel, and the carbon steel can be low carbon steel, medium carbon steel or high carbon steel. For example, the material of the pressure relief mechanism 24 can be: 304 stainless steel, 305 stainless steel, 316 stainless steel, etc.

[0252] Stainless steel and carbon steel have high strength, effectively enhancing the structural strength of the wall portion 213 and the pressure relief mechanism 24. This reduces the risk of deformation of the wall portion 213 and the pressure relief mechanism 24 due to stress, thus reducing the risk of premature valve opening of the pressure relief mechanism 24 and improving the service life and reliability of the battery cell 20. Furthermore, using at least one of stainless steel and carbon steel to manufacture the wall portion 213 can appropriately reduce its thickness. This, while maintaining the same volume, increases the internal space of the housing 21, thereby increasing energy density.

[0253] Optionally, the material of the wall portion 213 includes at least one of SU304 stainless steel, SU305 stainless steel, or SU316L stainless steel. The material of the pressure relief mechanism 24 includes at least one of SU304 stainless steel, SU305 stainless steel, or SU316L stainless steel.

[0254] 304 stainless steel, 305 stainless steel and 316L stainless steel have the advantages of corrosion resistance, high temperature resistance and good processing performance. The wall 213 and the pressure relief mechanism 24 made of 304 stainless steel, 305 stainless steel or 316L stainless steel have high strength, which can reduce the risk of deformation of the wall 213 and the pressure relief mechanism 24 due to force, which is beneficial to reducing the risk of the pressure relief mechanism 24 opening the valve to relieve pressure prematurely, which is beneficial to improving the service life and reliability of the battery cell 20, and is beneficial to improving the consistency of the detonation pressure of multiple battery cells 20.

[0255] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 In some embodiments, the thickness of the main body 2422 is H1, which satisfies: 0.05 mm ≤ H1 ≤ 0.5 mm. And / or the thickness of the connecting portion 241 is H2, which satisfies: 0.05 mm ≤ H2 ≤ 0.5 mm.

[0256] H1 represents the thickness of the main body 2422. When measuring, the thickness of the main body 2422 can be obtained by measuring in a direction perpendicular to the surface of the main body 2422. In addition, multiple measurements can be made and the average value can be taken as H1.

[0257] The thickness of the main body 2422 can be: H1 = 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0258] When H1 ≥ 0.05 mm, the thickness of the main body 2422 is greater, providing greater structural strength. This reduces the risk of deformation of the main body 2422 due to stress, thereby improving the service life and reliability of the battery cell 20. When H1 ≤ 0.5 mm, the thickness of the main body 2422 is not excessive, which helps control the manufacturing cost of the battery cell 20. Therefore, when 0.05 mm ≤ H1 ≤ 0.5 mm, the service life, reliability, and manufacturing cost of the battery cell 20 are balanced.

[0259] H2 represents the thickness of the connection portion 241. When measuring, the thickness of the connection portion 241 can be measured in a direction perpendicular to the surface of the connection portion 241 to obtain the thickness of the connection portion 241. In addition, multiple measurements can be made and the average value can be taken as H2.

[0260] The thickness of the connecting portion 241 may be: H2 = 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0261] When H2 ≥ 0.05 mm, the thickness of the connecting portion 241 is greater, providing greater structural strength. This reduces the risk of deformation of the connecting portion 241 due to stress, thereby improving the service life and reliability of the battery cell 20. When H2 ≤ 0.5 mm, the thickness of the connecting portion 241 is not excessively large, which helps control the manufacturing cost of the battery cell 20. Therefore, when 0.05 mm ≤ H2 ≤ 0.5 mm, the service life, reliability, and manufacturing cost of the battery cell 20 are balanced.

[0262] In some embodiments, the extension height of at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 is in the range of [0.2 mm, 7 mm].

[0263] An extension height of the first portion 24221 relative to the weak portion 2421 is a distance from an end of the first portion 24221 farthest from the weak portion 2421 to the weak portion 2421 along the thickness direction of the wall portion 213 .

[0264] The extension height of the second portion 2411 relative to the weak portion 2421 is: the distance from the end of the second portion 2411 farthest from the weak portion 2421 to the weak portion 2421 along the thickness direction of the wall portion 213 .

[0265] "The extended height of at least one of the first part 24221 and the second part 2411 relative to the weak part 2421 is in the range of [0.2 mm, 7 mm]" That is, the extended height of at least one of the first part 24221 and the second part 2411 relative to the weak part 2421 is greater than or equal to 0.2 mm and less than or equal to 7 mm.

[0266] An extension height of at least one of the first part 24221 and the second part 2411 relative to the weak portion 2421 may be: 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, etc.

[0267] When the height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weak portion 2421 is greater than or equal to 0.2 mm, the greater height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weak portion 2421 facilitates material flow during stamping and forming the weak portion 2421, improves stress in the weak portion 2421, and improves the structural stability of the formed weak portion 2421. When the height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weak portion 2421 is less than or equal to 7 mm, the height of at least one of the first portion 24221 and the second portion 2411 extending relative to the weak portion 2421 is not excessive. This, on the one hand, helps reduce the internal space occupied by the battery device 100 or the battery cell 20, thereby improving the energy density of the battery device 100 or the battery cell 20, and on the other hand, helps reduce the risk of interference with other components. Therefore, when the extension height of at least one of the first part 24221 and the second part 2411 relative to the weak portion 2421 is in the range of [0.2mm, 7mm], the life and energy density of the battery cell 20 can be taken into account while reducing the risk of interference with other components.

[0268] Optionally, the extension height of at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 is in the range of [0.3 mm, 5 mm].

[0269] The extension height of at least one of the first part 24221 and the second part 2411 relative to the weak part 2421 can be: 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, etc.

[0270] When the height of at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 is greater than or equal to 0.3 mm, the height of at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 is greater, facilitating material flow during stamping of the weak portion 2421, improving stress in the weak portion 2421, and ensuring greater structural stability of the formed weak portion 2421. When the height of at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 is less than or equal to 5 mm, the height of at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 is not excessively large. This, on the one hand, helps reduce the internal space occupied by the battery device 100 or the battery cell 20, thereby increasing the energy density of the battery device 100 or the battery cell 20, and on the other hand, helps reduce the risk of interference with other components. Therefore, when the extension height of at least one of the first part 24221 and the second part 2411 relative to the weak part 2421 is in the range of [0.3mm, 5mm], it is possible to better take into account the life and energy density of the battery cell 20 and reduce the risk of interference with other components.

[0271] Please refer to 6. Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 and Figure 11 , Figure 9 Cross-sectional views of the pressure relief mechanism 24 provided in some other embodiments of the present application. Figure 10 Schematic top view of the pressure relief mechanism 24 provided in some other embodiments of the present application. Figure 11 for Figure 10 In some embodiments, the first portion 24221 at least partially extends relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23 .

[0272] The first portion 24221 may extend relative to the weak portion 2421 at least partially in a direction close to the electrode assembly 23 . The first portion 24221 may also extend relative to the weak portion 2421 at least partially in a direction away from the electrode assembly 23 .

[0273] Please refer to Figure 6 and Figure 7 ,exist Figure 6 and Figure 7 In the illustrated embodiment, the first portion 24221 at least partially extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 , and the second portion 2411 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 .

[0274] Please refer to Figure 10 and Figure 11 ,exist Figure 10 and Figure 11 In the illustrated embodiment, the first portion 24221 at least partially extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 , and the second portion 2411 is a straight portion.

[0275] In addition, the first portion 24221 may extend entirely relative to the weak portion 2421 in a direction approaching or away from the electrode assembly 23 , or only a portion of the first portion 24221 may extend relative to the weak portion 2421 in a direction approaching or away from the electrode assembly 23 .

[0276] By extending the first portion 24221 at least partially relative to the weak portion 2421 in a direction toward or away from the electrode assembly 23, not only does this facilitate material flow during stamping and forming the weak portion 2421, thereby improving stress in the weak portion 2421, but it also increases the contact area with internal gas, thereby facilitating pressure release from the weak portion 2421. Thus, under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely rupture due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. Compared with the aluminum explosion-proof valve in the prior art, the thickness of the weak portion 2421 of the pressure relief mechanism 24 provided in the embodiment of the present application is smaller. During manufacturing, a slight change in the thickness of the weak portion 2421 will cause a large change in the bursting pressure of the battery cell 20. By making the first part 24221 at least partially extend relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23, the thickness of the weak portion 2421 can be increased under the same bursting pressure. The larger the thickness of the weak portion 2421, the easier it will be to manufacture, which is beneficial to improving the consistency of the detonation pressure of multiple battery cells 20.

[0277] Please refer to 6. Figure 7 and Figure 8 In some embodiments, the entire first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 .

[0278] Please refer to 6. Figure 7 and Figure 8 In the embodiment shown in the figure, the first portion 24221 extends as a whole relative to the weak portion 2421 in a direction away from the electrode assembly 23.

[0279] The existing pressure relief mechanism 24 will gradually arch from a flat plate structure in a direction away from the electrode assembly 23 under the action of the internal pressure of the battery cell 20 during pressure relief. After arching, it will open and release pressure under the action of the internal pressure of the battery cell 20. In the embodiment of the present application, the first portion 24221 extends entirely in a direction away from the electrode assembly 23 relative to the weak portion 2421, forming a pre-deformation, thereby facilitating the rupture of the weak portion 2421 to release pressure. In this way, under the same blasting pressure, the thickness of the weak portion 2421 can be greater. When the battery cell 20 is in normal use, the weak portion 2421 is not likely to rupture prematurely due to pressure changes inside the battery cell 20 or external impacts, which helps to reduce the risk of premature damage to the weak portion 2421 and helps to increase the life of the battery cell 20. By extending the entire first portion 24221 relative to the weak portion 2421 in a direction away from the electrode assembly 23, the main body 2422 has a larger contact area with the internal gas during pressure relief in the battery cell 20. This increases the external force applied to the first portion 24221, allowing the first portion 24221 to directly pull on the weak portion 2421, subjecting it to a greater shear force, thereby facilitating the opening of the weak portion 2421 and releasing pressure. Under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely crack due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. Furthermore, a thicker weak portion 2421 is easier to manufacture, thereby facilitating uniformity in the detonation pressure across multiple battery cells 20.

[0280] Please refer to Figure 9 In other embodiments, a portion of the first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 .

[0281] Please refer to Figure 9 ,exist Figure 9In the embodiment shown, the first portion 24221 at the left end of the main body 2422 is a straight portion, that is, the first portion 24221 at the left end of the main body 2422 does not extend relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23. The first portion 24221 at the right end of the main body 2422 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23. Therefore, in Figure 9 In the illustrated embodiment, a portion of the first portion 24221 extends relative to the weakened portion 2421 in a direction away from the electrode assembly 23 .

[0282] The existing pressure relief mechanism 24 will gradually arch from a flat plate structure in a direction away from the electrode assembly 23 under the action of the internal pressure of the battery cell 20 during pressure relief. After arching, it will open and release pressure under the action of the internal pressure of the battery cell 20. In the embodiment of the present application, a portion of the first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23, forming a pre-deformation, thereby facilitating the rupture of the weak portion 2421 to release pressure. In this way, under the same blasting pressure, the thickness of the weak portion 2421 can be greater. When the battery cell 20 is in normal use, the weak portion 2421 is not likely to rupture prematurely due to pressure changes inside the battery cell 20 or external impacts, which helps to reduce the risk of premature damage to the weak portion 2421 and helps to increase the life of the battery cell 20. By extending a portion of the first portion 24221 relative to the weak portion 2421 in a direction away from the electrode assembly 23, the main body 2422 has a larger contact area with the internal gas during pressure relief in the battery cell 20. This increases the external force exerted on the first portion 24221, allowing the first portion 24221 to directly pull on the weak portion 2421, subjecting it to greater shear force, thereby facilitating the opening of the weak portion 2421 and releasing pressure. Under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely rupture due to pressure fluctuations within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. Furthermore, a thicker weak portion 2421 facilitates manufacturing, thereby facilitating consistent detonation pressure across multiple battery cells 20. Furthermore, extending a portion of the first portion 24221 relative to the weak portion 2421 in a direction away from the electrode assembly 23 facilitates controlling the extended height of the main body 2422.

[0283] Please refer to Figures 3 to 11In some embodiments, the electrode assembly 23 includes at least two layers of electrode sheets, which are stacked in a first direction. Alternatively, the at least two layers of electrode sheets are wound, each including a planar section in the middle of the electrode assembly 23 and curved sections at both ends of the electrode assembly 23, with the planar sections of the at least two layers of electrode sheets stacked in the first direction. The main body 2422 has an arched cross-section along at least one plane perpendicular to the first direction.

[0284] When the electrode assembly 23 is a laminated electrode assembly, the first direction is the stacking direction of the multi-layer electrode sheets. When the electrode assembly 23 is a wound electrode assembly, the first direction is the stacking direction of the multi-layer electrode sheets in the plane section. Figure 4 , the first direction is the Z direction shown in the figure. Figure 7 、 Figure 9 and Figure 11 They are all cross-sections of the main body 2422 along a plane perpendicular to the first direction.

[0285] The arch shape may be an arch structure, or an arch-like structure, for example, a wave-shaped structure.

[0286] By making the main body 2422 have an arched cross-section in at least one plane perpendicular to the first direction, on the one hand, it facilitates material flow during the stamping and forming of the weak portion 2421, which helps improve the stress in the weak portion 2421 and improves the structural stability of the formed weak portion 2421. On the other hand, when the battery cell 20 is depressurized, the main body 2422 has a larger contact area with the internal gas, and the external force applied to the main body 2422 is greater. The main body 2422 can better transmit the force to the weak portion 2421, thereby pulling the weak portion 2421, resulting in a greater shear force on the weak portion 2421, which facilitates the opening and depressurization of the weak portion 2421. Under the same burst pressure, the thickness of the weak portion 2421 can be greater. During normal use of the battery cell 20, the weak portion 2421 is less likely to crack prematurely due to pressure changes within the battery cell 20 or external impact. This helps reduce the risk of premature damage to the weak portion 2421 and improves the life of the battery cell 20. On the other hand, when the battery cell 20 expands, the arch shape is more easily stretched under the action of external force, thereby reducing the risk of external force being transmitted to the weak portion 2421, further reducing the pulling of the weak portion 2421 by external force, and reducing the risk of the weak portion 2421 being damaged prematurely, which is beneficial to improving the life of the battery cell 20.

[0287] Please refer to Figures 3 to 11 In some embodiments, the extension height of the first portion 24221 relative to the weak portion 2421 is H3, satisfying: 0.5 mm ≤ H3 ≤ 5 mm.

[0288] H3 represents the extension height of the first portion 24221 relative to the weak portion 2421. In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245, and the position of the pressure relief mechanism 24 corresponding to the pressure relief groove 245 forms the weak portion 2421. Figure 6 and Figure 7 The pressure relief mechanism 24 has a first surface 246 and a second surface that are arranged opposite to each other in the thickness direction of the wall portion 213. One of the first surface 246 and the second surface faces the electrode assembly 23, and the other of the first surface 246 and the second surface is away from the electrode assembly 23. The pressure relief groove 245 is provided on the first surface 246. When the first surface 246 faces away from the electrode assembly 23, the maximum distance from the second surface to the inner surface of the first part 24221 can be measured as H3. When the first surface 246 faces the electrode assembly 23, the maximum distance from the second surface to the outer surface of the first part 24221 can be measured as H3. When the pressure relief grooves 245 are provided on both sides of the pressure relief mechanism 24 in the thickness direction of the wall portion 213, the maximum distance from the notch of the pressure relief groove 245 provided on the side of the pressure relief mechanism 24 facing away from the electrode assembly 23 to the outer surface of the first part 24221 can be measured as H3.

[0289] The extension height of the first portion 24221 relative to the weak portion 2421 can be: H3 = 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc.

[0290] When H3 ≥ 0.5 mm, the first portion 24221 extends a greater distance relative to the weak portion 2421. This results in more pronounced deformation of the main body 2422. Under the same burst pressure, the thickness of the weak portion 2421 is greater, which helps reduce the risk of premature failure of the weak portion 2421 and improves the lifespan of the battery cell 20. When H3 ≤ 5 mm, the first portion 24221 extends a lesser distance relative to the weak portion 2421. This not only reduces the internal space occupied by the battery device 100 or battery cell 20, improving the energy density of the battery device 100 or battery cell 20, but also reduces the risk of interference between the main body 2422 and other components. Therefore, when 0.5 mm ≤ H3 ≤ 5 mm, both the lifespan and energy density of the battery cell 20 are maintained while minimizing the risk of interference between the main body 2422 and other components.

[0291] Optionally, 0.8mm≤H3≤3mm.

[0292] The extension height of the first portion 24221 relative to the weak portion 2421 can be: 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, etc.

[0293] When H3 ≥ 0.8 mm, the first portion 24221 extends a greater distance relative to the weak portion 2421. This results in more pronounced deformation of the main body 2422. Under the same burst pressure, the thickness of the weak portion 2421 is greater, further reducing the risk of premature failure of the weak portion 2421 and improving the lifespan of the battery cell 20. When H3 ≤ 3 mm, the first portion 24221 extends a lesser distance relative to the weak portion 2421. This not only reduces the internal space occupied by the battery device 100 or battery cell 20, improving the energy density of the battery device 100 or battery cell 20, but also reduces the risk of interference between the main body 2422 and other components. Therefore, when 0.8 mm ≤ H3 ≤ 3 mm, a better balance is achieved between the lifespan and energy density of the battery cell 20, while also reducing the risk of interference between the main body 2422 and other components.

[0294] Please refer to Figure 12 、 Figure 13 and Figure 14 , Figure 12 Schematic top view of the pressure relief mechanism 24 provided in some further embodiments of the present application. Figure 13 for Figure 12 Cross-sectional view at the middle DD position. Figure 14 This is a cross-sectional view of the pressure relief mechanism 24 provided in some embodiments of the present application. In some embodiments, the second portion 2411 extends relative to the weak portion 2421 in a direction close to or away from the electrode assembly 23 .

[0295] The second portion 2411 may extend relative to the weak portion 2421 in a direction close to the electrode assembly 23 . The second portion 2411 may also extend relative to the weak portion 2421 in a direction away from the electrode assembly 23 .

[0296] Please refer to Figure 12 and Figure 13 ,exist Figure 12 and Figure 13 In the illustrated embodiment, the second portion 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 , and the first portion 24221 is a straight portion that does not extend relative to the weak portion 2421 in a direction toward or away from the electrode assembly 23 .

[0297] Please refer to Figure 14 ,exist Figure 14In the illustrated embodiment, the second portion 2411 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 , and the first portion 24221 also extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 .

[0298] By extending the second portion 2411 relative to the weak portion 2421 in a direction toward or away from the electrode assembly 23, on the one hand, it facilitates material flow during stamping and forming of the weak portion 2421, which helps to improve the stress of the weak portion 2421 and improve the structural stability of the formed weak portion 2421. On the other hand, when the battery cell 20 expands, the second portion 2411 can be stretched by external forces, thereby reducing the risk of external forces being transmitted to the weak portion 2421. This can further reduce the pulling of external forces on the weak portion 2421, reduce the risk of premature damage to the weak portion 2421, and help to improve the lifespan of the battery cell 20.

[0299] Please refer to Figure 12 、 Figure 13 and Figure 14 In some embodiments, the connecting portion 241 includes a third portion 2412 , the third portion 2412 is used to connect with the wall portion 213 , and the second portion 2411 connects the weak portion 2421 and the third portion 2412 .

[0300] The third portion 2412 is a portion of the connecting portion 241 used for connecting to the wall portion 213 . The third portion 2412 and the weak portion 2421 are respectively connected to two ends of the second portion 2411 .

[0301] Optionally, the third portion 2412 is a flat plate structure.

[0302] The third part 2412 is used to connect with the wall part 213, and the second wall part 213 connects the weak part 2421 and the third part 2412. During manufacturing, since the third part 2412 is farther away from the weak part 2421 than the second part 2411, it is not easy to affect the third part 2412 when processing the weak part 2421, so that the third part 2412 can maintain its original shape, thereby facilitating the connection between the third part 2412 and the wall part 213.

[0303] Please refer to Figure 12 、 Figure 13 and Figure 14 In some embodiments, the third portion 2412 is parallel to the wall portion 213 .

[0304] The third portion 2412 has a third surface facing the wall portion 213, and the wall portion 213 has a fourth surface facing the third portion 2412. The third surface and the fourth surface are parallel. It should be noted that the third surface and the fourth surface are substantially parallel, and the angle between the third surface and the fourth surface is less than 5 degrees.

[0305] By making the third portion 2412 parallel to the wall portion 213 , it is easier to connect the third portion 2412 to the wall portion 213 , which helps to increase the stability of the connection between the third portion 2412 and the wall portion 213 .

[0306] Please refer to Figure 12 、 Figure 13 and Figure 14 In some embodiments, the second portion 2411 is tilted relative to the third portion 2412, and the tilt angle of the second portion 2411 relative to the third portion 2412 is a, satisfying: 40°≤a≤75°.

[0307] a represents the inclination angle of the second portion 2411 relative to the third portion 2412. In this embodiment, the third portion 2412 is horizontal, and the inclination angle of the second portion 2411 relative to the third portion 2412 is the angle between the second portion 2411 and the horizontal direction. During measurement, the angle between a surface of the second portion 2411 and the horizontal plane can be measured.

[0308] The inclination angle of the second portion 2411 relative to the third portion 2412 can be: a=40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, etc.

[0309] When a ≥ 40°, the inclination of the connection portion 241 is greater, which better constrains the weak portion 2421 and helps reduce the risk of creep failure of the weak portion 2421. When a ≤ 75°, the inclination of the connection portion 241 is not too great, which helps reduce stress concentration and the risk of brittle fracture.

[0310] Please refer to Figure 6 、 Figure 7 and Figure 14 In some embodiments, both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 , and the direction in which the first portion 24221 extends relative to the weak portion 2421 is the same as the direction in which the second portion 2411 extends relative to the weak portion 2421 .

[0311] The first portion 24221 and the second portion 2411 may both extend relative to the weak portion 2421 in a direction away from the electrode assembly 23 , or the first portion 24221 and the second portion 2411 may both extend relative to the weak portion 2421 in a direction close to the electrode assembly 23 .

[0312] When the first portion 24221 extends in the same direction relative to the weak portion 2421 as the second portion 2411, the first portion 24221 can extend using the extended height of the second portion 2411. This helps reduce the height of the main portion 2422 above the surface of the connecting portion 241 farthest from the electrode assembly 23, or reduces the height of the main portion 2422 above the surface of the connecting portion 241 closest to the electrode assembly 23. This reduces the internal space occupied by the battery device 100 or battery cell 20, and helps improve the energy density of the battery device 100 or battery cell 20. Furthermore, when the battery cell 20 releases pressure, the first portion 24221 and the second portion 2411 exert opposite forces on the weak portion 2421, subjecting the weak portion 2421 to shear force and facilitating the opening of the weak portion 2421 to pressure relief. Under the same burst pressure, the thickness of the weak portion 2421 can be greater. During normal use of the battery cell 20, the weak portion 2421 is less likely to crack prematurely due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20. Furthermore, when the battery cell 20 expands, the first portion 24221 and the second portion 2411 are more easily stretched by external forces, thereby reducing the risk of external forces being transmitted to the weak portion 2421. This can further reduce the pulling of external forces on the weak portion 2421, reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20.

[0313] Please refer to Figure 14 In some embodiments, both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 in a direction close to the electrode assembly 23 .

[0314] When both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 in a direction approaching the electrode assembly 23, the first portion 24221 can utilize the extended height of the second portion 2411 to extend. This effectively reduces the height of the main portion 2422 above the surface of the connecting portion 241 closest to the electrode assembly 23, reduces the space occupied within the battery cell 20, and improves the energy density of the battery cell 20. Furthermore, when the battery cell 20 is depressurized, the first portion 24221 and the second portion 2411 exert opposite forces on the weak portion 2421, subjecting it to shear forces and facilitating its opening to release pressure. Under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely rupture due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20.

[0315] Please refer to Figure 6 and Figure 7 In other embodiments, both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 in a direction away from the electrode assembly 23 .

[0316] When both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 can utilize the extended height of the second portion 2411 to extend. This helps reduce the height of the main portion 2422 beyond the surface of the connecting portion 241 farthest from the electrode assembly 23, reduces the space occupied within the battery device 100, and improves the energy density of the battery device 100. Furthermore, when the battery cell 20 is depressurized, the first portion 24221 and the second portion 2411 exert opposite forces on the weak portion 2421, subjecting it to shear forces and facilitating its opening and pressure relief. Under the same burst pressure, the thickness of the weak portion 2421 can be increased. During normal use of the battery cell 20, the weak portion 2421 is less likely to prematurely rupture due to pressure changes within the battery cell 20 or external impacts, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20.

[0317] Please refer to Figure 15 and Figure 16 , Figure 15 Cross-sectional views of the pressure relief mechanism 24 provided in some other embodiments of the present application. Figure 16The present invention provides a cross-sectional view of a pressure relief mechanism 24 in some other embodiments. In some embodiments, the first portion 24221 and the second portion 2411 both extend relative to the weak portion 2421, and the direction in which the first portion 24221 extends relative to the weak portion 2421 is opposite to the direction in which the second portion 2411 extends relative to the weak portion 2421.

[0318] The direction in which the first part 24221 extends relative to the weak portion 2421 and the direction in which the second part 2411 extends relative to the weak portion 2421 are opposite: the first part 24221 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 and the second part 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23; or the first part 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 and the second part 2411 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23.

[0319] By making the direction in which the first portion 24221 extends relative to the weak portion 2421 opposite to the direction in which the second portion 2411 extends relative to the weak portion 2421, when the connecting portion 241 is connected to the wall portion 213, it is not easy to affect the weak portion 2421, which is beneficial to maintaining the performance of the weak portion 2421 and improving the life of the battery cell 20.

[0320] Please refer to Figure 15 In some embodiments, the first portion 24221 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 , and the second portion 2411 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 .

[0321] By extending the first portion 24221 relative to the weak portion 2421 in a direction close to the electrode assembly 23 and the second portion 2411 relative to the weak portion 2421 in a direction away from the electrode assembly 23, it is beneficial to reduce the occupation of the internal space of the battery device 100, improve the energy density of the battery device 100, and help reduce the risk of interference between the main body 2422 and other components in the battery device 100.

[0322] Please refer to Figure 16 In other embodiments, the first portion 24221 extends relative to the weak portion 2421 in a direction away from the electrode assembly 23 , and the second portion 2411 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 .

[0323] By extending the first part 24221 relative to the weak portion 2421 in a direction away from the electrode assembly 23 and the second part 2411 relative to the weak portion 2421 in a direction close to the electrode assembly 23, it is beneficial to reduce the occupation of the internal space of the battery cell 20, improve the energy density of the battery cell 20, and help reduce the risk of interference between the main body 2422 and other components in the battery cell 20.

[0324] Please refer again Figure 6 、 Figure 7 and Figure 8 In some embodiments, the minimum thickness of the weak portion 2421 is H4, satisfying 0.01 mm ≤ H4 ≤ 0.2 mm.

[0325] H4 represents the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 . During measurement, the thickness of the weak portion 2421 at different positions may be measured multiple times and the average value may be taken as H4 .

[0326] The minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.01 mm, 0.02 mm, 0.05 mm, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, etc.

[0327] When H4 ≥ 0.01 mm, the thickness of the weak portion 2421 is greater, making it less likely to prematurely crack due to pressure changes within the battery cell 20 or external impacts. This helps reduce the risk of premature damage to the weak portion 2421 and improves the lifespan of the battery cell 20. When H4 ≤ 0.2 mm, the thickness of the weak portion 2421 is not excessively large, allowing the pressure relief mechanism 24 to promptly open and release pressure in the event of thermal runaway of the battery cell 20, thereby improving the timeliness of the pressure relief mechanism 24's pressure relief. Therefore, when 0.01 mm ≤ H4 ≤ 0.2 mm, both the lifespan of the battery cell 20 and the timeliness of pressure relief are achieved.

[0328] In some embodiments, the projection area of ​​the main body 2422 along the thickness direction of the wall 213 is S; wherein 100mm 2 ≤450mm 2 , and 0.010mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2, and 0.025mm≤H4≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H4≤0.200mm.

[0329] S represents the projected area of ​​the main body 2422 along the thickness direction of the wall 213. Figure 6 , Figure 6 The S is marked with a mesh line. It should be noted that the mesh line here is only for the convenience of displaying S and does not represent any entity meaning.

[0330] The projected area of ​​the main body 2422 along the thickness direction of the wall 213 can be: S = 100 mm 2 , 150mm 2 , 200mm 2 , 250mm 2 , 300mm 2 , 350mm 2 , 400mm 2 , 450mm 2 , 500mm 2 , 550mm 2 , 600mm 2 、650mm 2 , 700mm 2 , 750mm 2 , 800mm 2 , 850mm 2 , 900mm 2 , 950mm 2 , 1000mm 2 , 1050mm 2 , 1100mm 2 , 1150mm 2 , 1200mm 2 , 1250mm 2 , 1300mm 2 , 1350mm 2 , 1400mm 2 , 1450mm 2 , 1500mm 2 , 1550mm 2 , 1600mm 2 , 1650mm 2 , 1700mm 2 , 1750mm 2 、1800mm 2 , 1850mm 2 , 1900mm 2 , 1950mm2 , 2000mm 2 、2050mm 2 , 2100mm 2 wait.

[0331] When 100mm 2 ≤S≤450mm 2 When 0.010mm≤H4≤0.160mm. When 100mm 2 ≤S≤450mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.010mm, 0.020mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, etc.

[0332] When the projected area of ​​the main body 2422 is larger, the main body 2422 is more susceptible to the internal pressure and the weak portion 2421 is cracked. Therefore, when the projected area of ​​the main body 2422 is increased, in order to ensure the same bursting pressure, the thickness of the weak portion 2421 can be increased. 2 <S≤450mm 2 , and H4 ≥ 0.010mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 100mm 2 <S≤450mm 2 , and when H4≤0.160mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 <S≤450mm 2 , and when 0.010mm≤H4≤0.160mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0333] When 350mm 2 ≤S≤850mm 2 When 0.015mm≤H4≤0.170mm. When 350mm 2 ≤S≤850mm 2, the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.015mm, 0.020mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, etc.

[0334] When 350mm 2 ≤S≤850mm 2 , and H4 ≥ 0.015mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 350mm 2 ≤S≤850mm 2 , and when H4≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤850mm 2 , and when 0.015mm≤H4≤0.170mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0335] When 750mm 2 ≤S≤1250mm 2 When 0.020mm≤H4≤0.180mm. When 750mm 2 ≤S≤1250mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.020mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, 0.180mm, etc.

[0336] When 750mm 2 ≤S≤1250mm 2, and H4 ≥ 0.020mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 750mm 2 ≤S≤1250mm 2 , and when H4≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤1250mm 2 , and when 0.020mm≤H4≤0.180mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0337] When 1150mm 2 ≤S≤1650mm 2 When 0.025mm≤H4≤0.190mm. When 1150mm 2 ≤S≤1650mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.025mm, 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, 0.180mm, 0.190mm, etc.

[0338] When 1150mm 2 ≤S≤1650mm 2 , and H4 ≥ 0.025mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not easily cracked prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1150mm 2 ≤S≤1650mm 2 , and when H4≤0.190mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.025mm≤H4≤0.190mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0339] When 1550mm 2 ≤S≤2100mm 2 When 0.030mm≤H4≤0.200mm. When 1550mm 2 ≤S≤2100mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.030mm, 0.040mm, 0.050mm, 0.060mm, 0.070mm, 0.080mm, 0.090mm, 0.100mm, 0.110mm, 0.120mm, 0.130mm, 0.140mm, 0.150mm, 0.160mm, 0.170mm, 0.180mm, 0.190mm, 0.200mm, etc.

[0340] When 1550mm 2 ≤S≤2100mm 2 , and H4 ≥ 0.030mm, the thickness of the weak portion 2421 is relatively large, and the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1550mm 2 ≤S≤2100mm 2 , and when H4≤0.200mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure in time when the battery cell 20 is in thermal runaway, which is conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.030mm≤H4≤0.200mm, both the service life of the battery cell 20 and the timeliness of pressure release can be taken into consideration.

[0341] In some embodiments, 100 mm 2 ≤S≤450mm 2 , and 0.020mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.025mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H4≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2, and 0.040mm≤H4≤0.200mm.

[0342] When 100mm 2 ≤S≤450mm 2 When 0.020mm≤H4≤0.160mm. When 100mm 2 ≤S≤450mm 2 , the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.020mm, 0.025mm, 0.030mm, 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, etc.

[0343] When 100mm 2 <S≤450mm 2 , and H4 ≥ 0.020mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 100mm 2 <S≤450mm 2 , and when H4≤0.160mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 <S≤450mm 2 , and when 0.020mm≤H4≤0.160mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0344] When 350mm 2 ≤S≤850mm 2 When 0.025mm≤H4≤0.170mm. When 350mm 2 ≤S≤850mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4=0.025mm, 0.030mm, 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, etc.

[0345] When 350mm 2 ≤S≤850mm 2 , and H4 ≥ 0.025mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 350mm 2 ≤S≤850mm 2 , and when H4≤0.170mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤850mm 2 , and when 0.025mm≤H4≤0.170mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0346] When 750mm 2 ≤S≤1250mm 2 When 0.030mm≤H4≤0.180mm. When 750mm 2 ≤S≤1250mm 2, the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.030mm, 0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, 0.175mm, 0.180mm, etc.

[0347] When 750mm 2 ≤S≤1250mm 2 , and when H4≥0.030mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 750mm 2 ≤S≤1250mm 2 , and when H4≤0.180mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤1250mm 2 , and when 0.030mm≤H4≤0.180mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0348] When 1150mm 2 ≤S≤1650mm 2 When 0.035mm≤H4≤0.190mm. When 1150mm 2 ≤S≤1650mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4=0.035mm, 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.125mm, 0.130mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, 0.175mm, 0.180mm, 0.185mm, 0.190mm, etc.

[0349] When 1150mm 2 ≤S≤1650mm 2 , and when H4≥0.035mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1150mm 2 ≤S≤1650mm 2 , and when H4≤0.190mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.035mm≤H4≤0.190mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0350] When 1550mm 2 ≤S≤2100mm 2 When 0.040mm≤H4≤0.200mm. When 1550mm 2 ≤S≤2100mm 2When the minimum thickness of the weak portion 2421 along the thickness direction of the wall portion 213 can be: H4 = 0.040mm, 0.045mm, 0.050mm, 0.055mm, 0.060mm, 0.065mm, 0.070mm, 0.075mm, 0.080mm, 0.085mm, 0.090mm, 0.095mm, 0.100mm, 0.105mm, 0.110mm, 0.115mm, 0.120mm, 0.12 5mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.125mm, 0.130mm, 0.135mm, 0.140mm, 0.145mm, 0.150mm, 0.155mm, 0.160mm, 0.165mm, 0.170mm, 0.175mm, 0.180mm, 0.185mm, 0.190mm, 0.195mm, 0.200mm, etc.

[0351] When 1550mm 2 ≤S≤2100mm 2 , and H4 ≥ 0.040mm, the thickness of the weak portion 2421 is greater, and the weak portion 2421 is less likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is more conducive to reducing the risk of premature damage to the weak portion 2421 and improving the life of the battery cell 20. When 1550mm 2 ≤S≤2100mm 2 , and when H4≤0.200mm, the thickness of the weak portion 2421 is not too large, so that the pressure relief mechanism 24 can open and release pressure more promptly when the battery cell 20 is in thermal runaway, which is more conducive to improving the timeliness of the pressure relief mechanism 24. 2 ≤S≤2100mm 2 , and when 0.040mm≤H4≤0.200mm, both the service life of the battery cell 20 and the timeliness of pressure release can be better taken into account.

[0352] Please refer to Figure 17 , Figure 17 Schematic diagram of the connection between the pressure relief mechanism 24, the wall portion 213 and the support structure 28 provided in some embodiments of the present application. In some embodiments, the connection portion 241 is welded to the wall portion 213.

[0353] The connecting portion 241 may be butt-welded to the wall portion 213 , or may be penetration-welded to the wall portion 213 .

[0354] The base materials of the pressure relief mechanism 24 and the wall portion 213 are both iron, and the connection portion 241 and the wall portion 213 are easier to weld, which helps to reduce the phenomenon of welding cracks between the pressure relief mechanism 24 and the wall portion 213, thereby reducing the risk of leakage of the battery cell 20 and improving the reliability of the battery cell 20.

[0355] Please refer to Figure 17 In some embodiments, the battery cell 20 further includes a support structure 28, which is fixed to the side of the wall portion 213 facing the electrode assembly 23. The pressure relief mechanism 24 is located on the side of the support structure 28 away from the electrode assembly 23. The connection portion 241 is welded to the support structure 28, and the base material of the support structure 28 is iron.

[0356] The support structure 28 is located on the side of the wall portion 213 facing the electrode assembly 23, and on the side of the pressure relief mechanism 24 facing the electrode assembly 23. Along the thickness of the wall portion 213, a portion of the support structure 28 is stacked with the wall portion 213, while another portion of the support structure 28 is stacked with the pressure relief mechanism 24. This reduces the space occupied by the support structure 28 outside the battery cell 20 and facilitates the secure connection between the pressure relief mechanism 24 and the wall portion 213.

[0357] Optionally, the supporting mechanism is annular.

[0358] “The base material of the support structure 28 is iron” means that iron is the largest material by mass in the materials of the support structure 28. For example, the material of the support structure 28 can be carbon steel or stainless steel.

[0359] The connection portion 241 is welded to the wall portion 213 and the support structure 28 to provide a higher connection strength.

[0360] By providing the support structure 28, when welding the connection portion 241 and the wall portion 213, the support structure 28 can reduce the risk of the laser penetrating the gap between the connection portion 241 and the wall portion 213 and affecting the electrode assembly 23, thereby improving the reliability of the battery cell 20. Furthermore, the support structure 28 can serve as a positioning mechanism during the fixed connection between the pressure relief mechanism 24 and the wall portion 213. The support structure 28 can also be used to secure the connection between the pressure relief mechanism 24 and the wall portion 213, effectively improving the processing efficiency of the battery cell 20. The support structure 28 can also support the pressure relief mechanism 24 and the wall portion 213, increasing the structural strength and stability between the wall portion 213 and the pressure relief mechanism 24. In particular, during use, when the battery cell 20 expands, the support structure 28 can resist deformation, reduce cracking between the pressure relief mechanism 24 and the wall portion 213 caused by the expansion of the battery cell 20, and improve the stability of the battery cell 20.

[0361] In some embodiments, the support structure 28 and the wall portion 213 are fixed by welding or bonding.

[0362] When the support structure 28 is welded to the wall 213, there is a high connection strength between the support structure 28 and the wall 213. When the support structure 28 is adhesively bonded to the wall 213, the connection between the support structure 28 and the wall 213 is more convenient, which is conducive to reducing production costs.

[0363] Please refer to Figure 17 In some embodiments, along the direction approaching the electrode assembly 23 , the pressure relief mechanism 24 does not exceed the surface of the support structure 28 facing the electrode assembly 23 .

[0364] Regardless of whether at least one of the first part 24221 and the second part 2411 of the pressure relief mechanism 24 extends relative to the weak portion 2421 in a direction close to the electrode assembly 23 or extends relative to the weak portion 2421 in a direction away from the electrode assembly 23, the surface of the pressure relief mechanism 24 facing the electrode assembly 23 does not exceed the surface of the support structure 28 facing the electrode assembly 23 to protect the pressure relief mechanism 24.

[0365] By ensuring that the pressure relief mechanism 24 does not exceed the surface of the support structure 28 facing the electrode assembly 23 in the direction approaching the electrode assembly 23, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism 24 and other components in the battery cell 20. On the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism 24 being subjected to external forces exerted on the pressure relief mechanism 24 by other components of the battery cell 20, so that the weak portion 2421 is not easily cracked prematurely, which is beneficial to reduce the risk of the weak portion 2421 being damaged prematurely and to improve the life of the battery cell 20.

[0366] Please refer to Figure 17 In some embodiments, the thickness of the support structure 28 is H5, which satisfies: 0.4 mm ≤ H5 ≤ 1.5 mm.

[0367] H5 represents the thickness of the support structure 28. During measurement, multiple measurements may be performed and the average value may be taken as H5.

[0368] The thickness of the support structure 28 can be: H5 = 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, 1.5 mm, etc.

[0369] When H5 ≥ 0.4 mm, the thickness of the support structure 28 is relatively large, and the laser during welding is not easy to penetrate the support structure 28. This can effectively reduce the risk of the laser passing through the gap between the connecting portion 241 and the wall portion 213 and acting on the electrode assembly 23, which is beneficial to improving the reliability of the battery cell 20. When H5 ≤ 1.5 mm, the thickness of the support structure 28 is not too large. On the one hand, it can reduce the occupation of the internal space of the battery cell 20 by the support structure 28 and improve the energy density of the battery cell 20. On the other hand, it can reduce the material consumption of the support structure 28 and reduce the manufacturing cost of the battery cell 20. Therefore, when 0.4 mm ≤ H5 ≤ 1.5 mm, the reliability, energy density and manufacturing cost of the battery cell 20 can be taken into account.

[0370] Optionally, 0.4mm≤H5≤0.8mm.

[0371] The thickness of the support structure 28 can be: H5 = 0.4mm, 0.42mm, 0.45mm, 0.48mm, 0.5mm, 0.52mm, 0.55mm, 0.58mm, 0.6mm, 0.62mm, 0.65mm, 0.68mm, 0.7mm, 0.72mm, 0.75mm, 0.78mm, 0.8mm, etc.

[0372] When H5 ≥ 0.4 mm, the thickness of the support structure 28 is relatively large, and the laser during welding is not easy to penetrate the support structure 28. This can effectively reduce the risk of the laser passing through the gap between the connecting portion 241 and the wall portion 213 and acting on the electrode assembly 23, which is beneficial to improving the reliability of the battery cell 20. When H5 ≤ 0.8 mm, the thickness of the support structure 28 is not too large. On the one hand, it can further reduce the occupation of the internal space of the battery cell 20 by the support structure 28, thereby improving the energy density of the battery cell 20. On the other hand, it can further reduce the material consumption of the support structure 28 and reduce the manufacturing cost of the battery cell 20. Therefore, when 0.4 mm ≤ H5 ≤ 0.8 mm, it can better take into account the reliability, energy density and manufacturing cost of the battery cell 20.

[0373] Please refer to Figure 17 In some embodiments, the pressure relief mechanism 24 , the wall portion 213 , and the support structure 28 are connected via a common weld 281 .

[0374] The wall portion 213 is provided with a pressure relief hole 2131, and the pressure relief mechanism 24 is accommodated in the pressure relief hole 2131. The outer peripheral surface of the pressure relief mechanism 24, the hole wall surface of the pressure relief hole 2131 and the support structure 28 are connected by the same weld 281. Figure 17The connection portion 241 and the wall of the pressure relief hole 2131 can be fixed by butt welding to form a weld 281 . At the same time, the support structure 28 is also welded to the side of the weld 281 facing the interior of the battery cell 20 .

[0375] During welding, the pressure relief mechanism 24, the wall portion 213 and the support structure 28 can be welded together at one time, which makes the manufacturing simple and convenient.

[0376] Please refer to Figure 18 , Figure 18 Schematic diagram of the connection between the pressure relief mechanism 24, wall portion 213, support structure 28, and separator 29 provided in some embodiments of the present application. In some embodiments, the battery cell 20 further includes a separator 29, which is disposed on the side of the wall portion 213 facing the electrode assembly 23. As it approaches the electrode assembly 23, the pressure relief mechanism 24 at least partially protrudes from the surface of the wall portion 213 facing the electrode assembly 23, and the separator 29 protrudes from the surface of the pressure relief mechanism 24 facing the electrode assembly 23.

[0377] The separator 29 is disposed on a side of the wall portion 213 facing the electrode assembly 23 . The separator 29 protrudes from a surface of the pressure relief mechanism 24 facing the electrode assembly 23 to protect the pressure relief mechanism 24 .

[0378] In some embodiments, separator 29 protrudes from the surface of support structure 28 facing electrode assembly 23. In other embodiments, the surface of separator 29 facing electrode assembly 23 is flush with the surface of support structure 28 facing electrode assembly 23.

[0379] When the wall portion 213 is the end cap 212, the separator 29 can be a lower plastic. When the wall portion 213 is the side wall of the housing 211, the separator 29 can be a side support plate. When the wall portion 213 is the bottom wall of the housing 211, the separator 29 can be a bottom support plate. Of course, the separator 29 can also be an additional backing plate.

[0380] The pressure relief mechanism 24 at least partially protrudes from the surface of the wall portion 213 facing the electrode assembly 23 in the direction close to the electrode assembly 23. By making the separator 29 protrude from the surface of the pressure relief mechanism 24 facing the electrode assembly 23 in the direction close to the electrode assembly 23, on the one hand, it is beneficial to reduce the risk of interference between the pressure relief mechanism 24 and other components in the battery cell 20. On the other hand, it is also beneficial to reduce the risk of the pressure relief mechanism 24 being subjected to external force exerted on the pressure relief mechanism 24 by other components of the battery cell 20, so that the weak portion 2421 is not easy to crack prematurely, which is beneficial to reduce the risk of the weak portion 2421 being damaged prematurely and is beneficial to improving the life of the battery cell 20.

[0381] Please refer to Figure 18 and Figure 19 , Figure 19Schematic diagram of the structure of the separator 29 provided in some embodiments of the present application. In some embodiments, the separator 29 includes a fourth portion 291 and a fifth portion 292 spaced apart from each other, and the pressure relief mechanism 24 is located between the fourth portion 291 and the fifth portion 292.

[0382] The fourth portion 291 and the fifth portion 292 are independent of each other and are not connected to each other. During manufacture, the fourth portion 291 and the fifth portion 292 can be manufactured separately and assembled at both ends of the pressure relief mechanism 24.

[0383] The separator 29 includes a fourth portion 291 and a fifth portion 292 spaced apart from each other. Positioning the pressure relief mechanism 24 between the fourth and fifth portions 291, 292 prevents the pressure relief mechanism 24 from opening and releasing pressure, allowing the battery cells 20 to release pressure in a timely manner. Furthermore, during manufacturing, the fourth and fifth portions 291, 292 can be manufactured separately and then positioned on either side of the pressure relief mechanism 24, simplifying manufacturing and reducing assembly complexity.

[0384] Optionally, the partition 29 may also include more than two split structures, which are spaced around the pressure relief mechanism 24 to protect the pressure relief mechanism 24. This arrangement makes the partition 29 more flexible.

[0385] Please refer to Figure 20 , Figure 20 Schematic diagram of the structure of the separator 29 provided in some other embodiments of the present application. In some other embodiments, the separator 29 is provided with an escape opening 293 , and the escape opening 293 is used to escape the pressure relief mechanism 24 .

[0386] The avoidance opening 293 is a through hole provided in the partition 29. Optionally, the shape of the avoidance opening 293 matches the outer contour of the pressure relief mechanism 24. For example, when the outer contour of the pressure relief mechanism 24 is in a runway shape, the avoidance opening 293 may also be in a runway shape.

[0387] By providing the avoidance opening 293 to avoid the pressure relief mechanism 24 , it is beneficial for the pressure relief mechanism 24 to open and relieve pressure when the pressure inside the housing 21 reaches a threshold.

[0388] Please refer to Figure 21 and Figure 22 , Figure 21 The following are cross-sectional views of the separator 29 provided in some other embodiments of the present application. Figure 22This is a cross-sectional view of a separator 29 provided in some further embodiments of the present application. In yet other embodiments, the separator 29 is provided with a receiving groove 294 that opens toward the pressure relief mechanism 24. The receiving groove 294 is configured to receive the pressure relief mechanism 24. The bottom of the receiving groove 294 is provided with a thinned region 2941 corresponding to the pressure relief mechanism 24. The thickness of the thinned region 2941 is less than the thickness of other areas at the bottom of the receiving groove 294.

[0389] On the one hand, the internal space of the accommodating groove 294 can be used to avoid the pressure relief mechanism 24 and the support structure 28. The thinning area 2941 set on the bottom wall of the accommodating groove 294 can be used to be destroyed in time when the battery cell 20 has thermal runaway, so as to reduce the impact of the bottom wall of the accommodating groove 294 on the pressure relief mechanism 24, so that the pressure relief mechanism 24 can be destroyed in time and the pressure inside the battery cell 20 can be released in time.

[0390] Please refer to Figure 21 ,exist Figure 21 In the illustrated embodiment, the thinned area 2941 of the bottom wall of the accommodating groove 294 may be a groove structure, and the area of ​​the thinned area 2941 at least covers the weak portion 2421 of the pressure relief mechanism 24 to reduce the impact on the actuation of the pressure relief mechanism 24.

[0391] Please refer to Figure 22 ,exist Figure 22 In the illustrated embodiment, the thinned area 2941 of the bottom wall of the accommodating groove 294 may also be an annular structure, so that the thinned area 2941 corresponds to the annular weak portion 2421 of the pressure relief mechanism 24 to reduce the impact on the actuation of the pressure relief mechanism 24.

[0392] Providing a receiving groove 294 to accommodate the pressure relief mechanism 24 not only helps reduce the risk of interference between the pressure relief mechanism 24 and other components within the battery cell 20, but also helps reduce the risk of external forces exerted on the pressure relief mechanism 24 by other components of the battery cell 20. This prevents the weak portion 2421 from prematurely cracking, helps reduce the risk of premature damage to the weak portion 2421, and helps improve the lifespan of the battery cell 20. By forming a thinned area 2941 at the bottom of the receiving groove 294, the thinned area 2941 can open when the pressure inside the housing 21 reaches a threshold, allowing gas within the housing 21 to flow toward the pressure relief mechanism 24, thereby facilitating the opening and pressure relief of the pressure relief mechanism 24.

[0393] It should be understood that the dimensions of the separator 29 in the embodiment of the present application can be adjusted based on actual application. For example, if the separator 29 is provided with an escape opening 293 or a receiving groove 294, the dimensions of the escape opening 293 or the receiving groove 294 in all directions are generally greater than or equal to the dimensions of the pressure relief mechanism 24 to reduce obstruction of the escape opening 293 or the receiving groove 294 on the pressure relief mechanism 24, thereby enabling the pressure relief mechanism 24 to be activated promptly when thermal runaway of the battery cell 20 occurs.

[0394] It should be understood that the material of the separator 29 of the embodiment of the present application can be set according to the actual application. For example, the separator 29 is generally made of an insulating material. For another example, the material of the separator 29 includes plastic to reduce costs and facilitate processing.

[0395] It should be understood that the method for securing the separator 29 in the embodiment of the present application can be configured according to actual application. For example, the separator 29 can be secured to the wall portion 213 using an adhesive, which is simple and easy to implement, and has a stable structure, reducing the risk of misalignment between the separator 29 and the wall portion 213, or even the risk of the separator 29 falling.

[0396] Please refer again Figure 18 In some embodiments, along the thickness direction of the wall portion 213 , the pressure relief mechanism 24 does not extend beyond the surface of the wall portion 213 farthest from the electrode assembly 23 in a direction away from the electrode assembly 23 .

[0397] Along the thickness direction of the wall portion 213 , the wall portion 213 has an inner surface and an outer surface that are relatively arranged, wherein the inner surface faces the electrode assembly 23 and the outer surface faces away from the electrode assembly 23 . The outer surface can be the surface of the wall portion 213 farthest from the electrode assembly 23 .

[0398] When the pressure relief mechanism 24 does not exceed the surface of the wall 213 farthest from the electrode assembly 23 in the direction away from the electrode assembly 23, the surface of the pressure relief mechanism 24 farthest from the electrode assembly 23 can be flush with the surface of the wall 213 farthest from the electrode assembly 23, and the surface of the pressure relief mechanism 24 farthest from the electrode assembly 23 can also be closer to the electrode assembly 23 than the surface of the wall 213 farthest from the electrode assembly 23.

[0399] By ensuring that the pressure relief mechanism 24 does not extend beyond the surface of the wall 213 farthest from the electrode assembly 23 along the thickness direction of the wall 213, the internal space occupied by the battery device 100 can be reduced, thereby improving the energy density of the battery device 100. Furthermore, the pressure relief mechanism 24 is less likely to interfere with other components and be susceptible to external forces, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20.

[0400] Please refer to Figure 23 , Figure 23Schematic diagrams showing the wall portion 213 provided with an electrode terminal 25 in some embodiments of the present application. In other embodiments, the battery cell 20 further includes an electrode terminal 25 disposed on the wall portion 213, with at least a portion of the electrode terminal 25 protruding from the wall portion 213 in a direction away from the electrode assembly 23. Along the thickness of the wall portion 213, the pressure relief mechanism 24 does not extend beyond the surface of the electrode terminal 25 furthest from the electrode assembly 23.

[0401] The electrode terminal 25 is used to electrically connect to the tab 232 of the electrode assembly 23 to input or output electrical energy from the battery cell 20. The electrode terminal 25 and the tab 232 can be directly connected, for example, by direct welding. The electrode terminal 25 and the tab 232 can also be indirectly connected, for example, by indirectly connecting the electrode terminal 25 and the tab 232 through a current collecting member. The electrode terminal 25 can be insulated and disposed on the wall portion 213, and at least partially protrude from the outer surface of the wall portion 213.

[0402] When the pressure relief mechanism 24 does not exceed the surface of the electrode terminal 25 farthest from the electrode assembly 23 in the direction away from the electrode assembly 23, the surface of the pressure relief mechanism 24 farthest from the electrode assembly 23 can be flush with the surface of the electrode terminal 25 farthest from the electrode assembly 23, and the surface of the pressure relief mechanism 24 farthest from the electrode assembly 23 can also be closer to the electrode assembly 23 than the surface of the electrode terminal 25 farthest from the electrode assembly 23.

[0403] By ensuring that the pressure relief mechanism 24 does not extend beyond the surface of the electrode terminal 25 farthest from the electrode assembly 23 along the thickness direction of the wall portion 213, the internal space occupied by the battery device 100 can be reduced, thereby improving the energy density of the battery device 100. Furthermore, the pressure relief mechanism 24 is less likely to interfere with other components and be susceptible to external forces, thereby reducing the risk of premature damage to the weak portion 2421 and improving the lifespan of the battery cell 20.

[0404] Please refer again Figure 5 、 Figure 6 and Figure 7 In some embodiments, the weak portion 2421 is in the shape of a closed ring, and the thickness of the weak portion 2421 is the same at all locations.

[0405] The weak portion 2421 is an annular structure, and the weak portion 2421 can be in the shape of a circular ring or an elliptical ring.

[0406] “The thickness of the weak portion 2421 is the same at all locations” means that the thickness of the cross sections of the weak portion 2421 at any two locations along the extending direction thereof are equal.

[0407] By making the weak portion 2421 a closed ring with equal thickness at all locations, when the pressure inside the shell 21 reaches a threshold value, the pressure relief mechanism 24 can split along the entire circumference of the weak portion 2421, so that the main body 2422 can be separated from the pressure relief mechanism 24. The main body 2422 is not easy to hang on the second part 2411, and is not easy to block the gas eruption, thereby reducing the risk of spraying high-temperature gas to adjacent battery cells 20, which is beneficial to improving the reliability of the battery cells 20.

[0408] Please refer to Figure 24 and Figure 25 , Figure 24 Schematic top view of the pressure relief mechanism 24 provided in some further embodiments of the present application. Figure 25 for Figure 24 A cross-sectional view taken at the center EE position. In other embodiments, the weak portion 2421 is in a closed ring shape. The weak portion 2421 includes a first weak section 24212 and a second weak section 24213 connected end to end. The second weak section 24213 is thicker than the first weak section 24212. The second weak section 24213 is located on one side of the weak portion 2421 along the length of the wall portion 213.

[0409] The first weak section 24212 serves as a pressure relief mechanism, and is used to enable the pressure relief mechanism 24 to rupture along at least a portion of the first weak section 24212 to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0410] The second weak section 24213 guides at least a portion of the main body 2422 to flip open. The second weak section 24213 is stronger than the first weak section 24212. When the battery cell 20 releases pressure, the first weak section 24212 first ruptures, allowing the fluid inside the battery cell 20 to escape and release pressure. Subsequently, under the influence of the fluid, the main body 2422 can flip outward, pivoting around the second weak section 24213, to create a larger opening and achieve rapid pressure relief.

[0411] Please refer to Figure 24 The first weak section 24212 includes a first section 24212a, a second section 24212b, and a third section 24212c. The first section 24212a and the third section 24212c are arranged opposite each other. One end of the second section 24212b is connected to one end of the first section 24212a, and the other end of the second section 24212b is connected to one end of the third section 24212c. The second weak section 24213 connects the other end of the first section 24212a and the other end of the third section 24212c. The first section 24212a, the second section 24212b, the third section 24212c, and the second weak section 24213 collectively define the main body 2422.

[0412] Please refer to Figure 24 , the length direction of the wall portion 213 is the Y direction shown in the figure.

[0413] The second weak section 24213 is located on one side of the weak portion 2421 in the length direction of the wall portion 213. Figure 24 The left-right direction is the length direction of the wall portion 213. In this case, the second weak section 24213 is located to the left of the weak portion 2421. Thus, when the battery cell 20 is depressurized, even if the main body 2422 is not fully opened, the ejected high-temperature gas will diffuse along the length direction of the wall portion 213 under the action of the main body 2422. In other words, the ejected high-temperature gas is unlikely to be directed toward another adjacent battery cell 20.

[0414] The provision of the second weak section 24213 weakens the strength of the pressure relief mechanism 24 at the location of the second weak section 24213, making it easier for the main body 2422 to flip open under the influence of the internal gas pressure of the battery cell 20. This not only increases the probability of the main body 2422 opening, but also increases the speed of the main body 2422 opening, achieving rapid pressure relief, reducing the risk of explosion or fire in the battery cell 20, and thus improving the reliability of the battery cell 20. By locating the second weak section 24213 on the side of the weak section 2421 in the longitudinal direction of the wall 213, when the battery cell 20 releases pressure, even if the main body 2422 is not fully opened, the ejected high-temperature gas will diffuse along the longitudinal direction of the wall 213 under the influence of the main body 2422. In other words, the ejected high-temperature gas is less likely to be directed toward another adjacent battery cell 20, thereby less likely to cause thermal runaway in the other battery cell 20, thereby improving the reliability of the battery device 100.

[0415] Please refer to Figure 26 , Figure 26 Schematic top view of the pressure relief mechanism 24 provided in some other embodiments of the present application. In some other embodiments, the weak portion 2421 is open-shaped, and the open end of the weak portion 2421 is located on one side of the weak portion 2421 in the length direction of the wall portion 213.

[0416] The weak portion 2421 may be in a C-shaped, U-shaped or other shape with an opening at one end. The opening end of the weak portion 2421 is located on one side of the weak portion 2421 in the length direction of the wall portion 213. Figure 26 The left-right direction is the length direction of the wall portion 213. In this case, the open end of the weak portion 2421 is located on the left side of the weak portion 2421. In this way, when the battery cell 20 is depressurized, even if the main body 2422 is not fully opened, the ejected high-temperature gas will diffuse along the length direction of the wall portion 213 under the action of the main body 2422. In other words, the ejected high-temperature gas is unlikely to be directed toward another adjacent battery cell 20.

[0417] By positioning the open end of the weak portion 2421 on one side of the weak portion 2421 in the longitudinal direction of the wall portion 213, when the battery cell 20 is depressurized, even if the main body portion 2422 is not fully opened, the ejected high-temperature gas will diffuse toward the longitudinal direction of the wall portion 213 under the action of the main body portion 2422. This means that the ejected high-temperature gas is less likely to be directed toward another adjacent battery cell 20, and is less likely to cause thermal runaway of another battery cell 20, thereby improving the reliability of the battery device 100.

[0418] Please refer again Figure 6 、 Figure 7 and Figure 8 In some embodiments, the pressure relief mechanism 24 is provided with a pressure relief groove 245 , and a bottom wall of the pressure relief groove 245 forms a weak portion 2421 .

[0419] By providing a pressure relief groove 245 on the pressure relief mechanism 24 , a weak portion 2421 is formed on the pressure relief mechanism 24 . When the battery cell 20 releases pressure, the pressure relief mechanism 24 is split along at least a portion of the weak portion 2421 . This is simple, convenient, and low-cost.

[0420] Optionally, the pressure relief groove 245 is formed by stamping.

[0421] Forming the pressure relief groove 245 by stamping makes it easier to control the thickness of the weak portion 2421 and has higher processing accuracy, which is beneficial for ensuring that the bursting pressure of multiple battery cells 20 remains consistent when manufacturing multiple battery cells 20, and is beneficial for improving the reliability of the battery cells 20.

[0422] Please refer to Figure 6 、 Figure 7 and Figure 8 In some embodiments, the cross section of the pressure relief groove 245 is trapezoidal or conical.

[0423] When the cross section of the pressure relief groove 245 is trapezoidal or conical, it is beneficial for the main body 2422 to quickly open and release pressure when the battery cell 20 experiences thermal runaway.

[0424] Please refer to Figure 6 、 Figure 7 and Figure 8 In some embodiments, along the width direction of the pressure relief groove 245 , the pressure relief groove 245 includes two groove side surfaces 2452 arranged opposite to each other, and the angle between the two groove side surfaces 2452 is b, satisfying: 30°≤b≤90°.

[0425] Please refer to Figure 8 The width direction of the pressure relief groove 245 is the N direction shown in the figure.

[0426] b represents the angle between the two groove side surfaces 2452. The angle between the two groove side surfaces 2452 can be: b = 30°, 35°, 40°, 45°, b = 50°, 55°, 60°, 65°, b = 70°, 75°, 80°, 85°, 90°, etc.

[0427] When b ≥ 30°, the pressure relief groove 245 can be easily punched out, reducing the difficulty of processing the pressure relief groove 245, thereby reducing the manufacturing cost of the battery cell 20. When b ≤ 90°, it can reduce material extrusion. Therefore, when 30° ≤ b ≤ 90°, it can reduce both the manufacturing cost of the battery cell 20 and the extrusion of material.

[0428] Optionally, 40°≤b≤80°.

[0429] The included angle between the two groove side surfaces 2452 can be: b=40°42°, 45°, 48°, b=50°, 52°, 55°, 58°, 60°, 62°, 65°, 68°, b=70°, 72°, 75°, 78°, 80°, etc.

[0430] When b ≥ 40°, the pressure relief groove 245 can be punched out more easily, reducing the difficulty of processing the pressure relief groove 245, thereby further reducing the manufacturing cost of the battery cell 20. When b ≤ 80°, it can further reduce material extrusion. Therefore, when 40° ≤ b ≤ 80°, it can reduce both the manufacturing cost of the battery cell 20 and the extrusion of material.

[0431] In some embodiments, the pressure relief mechanism 24 is provided separately from the wall portion 213 . The wall portion 213 is provided with a pressure relief hole 2131 . The pressure relief mechanism 24 is installed on the wall portion 213 and covers the pressure relief hole 2131 .

[0432] The phrase "pressure relief mechanism 24 is provided separately from wall portion 213, wall portion 213 is provided with a pressure relief hole 2131, and pressure relief mechanism 24 is mounted on wall portion 213 and covers pressure relief hole 2131" means that during manufacturing, pressure relief hole 2131 is provided on wall portion 213, and the pressure relief mechanism 24 and wall portion 213 are provided separately and ultimately connected together. For example, the pressure relief mechanism 24 can be welded to wall portion 213. The pressure relief mechanism 24 can be a bursting disk mounted on wall portion 213.

[0433] In some embodiments, the pressure relief mechanism 24 is disposed at the end of the pressure relief hole 2131 facing the electrode assembly 23 . The battery cell 20 includes a protective member 26 disposed at the end of the pressure relief hole 2131 facing away from the electrode assembly 23 and covering the pressure relief hole 2131 .

[0434] The pressure relief mechanism 24 is provided separately from the wall portion 213 and is installed on the wall portion 213 , thereby facilitating processing and manufacturing.

[0435] In other embodiments, the pressure relief mechanism 24 and the wall portion 213 are integrally formed.

[0436] Integrally formed means that the wall portion 213 and the pressure relief mechanism 24 are an integral structure when provided. For example, the pressure relief mechanism 24 can be formed on the wall portion 213 by stamping or cold heading.

[0437] Integrating the pressure relief mechanism 24 with the wall portion 213 eliminates the need for additional welding or bonding processes, which helps reduce the risk of leakage from the pressure relief mechanism 24. Furthermore, during production, it is easier to ensure that the detonation pressures of multiple battery cells 20 produced are more consistent.

[0438] Please refer to Figure 5 、 Figure 6 and Figure 7 The embodiment of the present application further provides a pressure relief mechanism 24, which is used for the battery cell 20. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak portion 2421, a main body 2422 and a connecting portion 241. The weak portion 2421 is configured to be at least partially destroyed to release the pressure when the pressure inside the battery cell 20 reaches a threshold value. The main body 2422 is located in the area surrounded by the weak portion 2421, and the connecting portion 241 is located on the outside of the weak portion 2421. The portion of the main body 2422 close to the weak portion 2421 is the first portion 24221, and the portion of the connecting portion 241 close to the weak portion 2421 is the second portion 2411. At least one of the first portion 24221 and the second portion 2411 extends relative to the weak portion 2421 along the thickness direction of the pressure relief mechanism 24.

[0439] Please refer to Figure 27 , Figure 27 This is a schematic block diagram of a pressure relief mechanism manufacturing method 30 provided in some embodiments of the present application. The present application also provides a pressure relief mechanism manufacturing method 30, wherein the pressure relief mechanism 24 is used for a battery cell 20, and the pressure relief mechanism manufacturing method 30 includes:

[0440] Step S100: providing a sheet, wherein the substrate of the sheet is iron;

[0441] Step S200: Processing a weak portion 2421 on the material sheet. The weak portion 2421 is configured to be at least partially destroyed to release the pressure when the pressure inside the battery cell 20 reaches a threshold. The portion of the material sheet within the area enclosed by the weak portion 2421 is the main body 2422, and the portion of the material sheet outside the area enclosed by the weak portion 2421 is the connecting portion 241.

[0442] Among them, the part of the main body 2422 close to the weak part 2421 is the first part 24221, and the part of the connecting part 241 close to the weak part 2421 is the second part 2411. At least one of the first part 24221 and the second part 2411 extends relative to the weak part 2421 along the thickness direction of the sheet.

[0443] Please refer to Figure 28 , Figure 28 This is a schematic block diagram of a pressure relief mechanism manufacturing method 30 provided in some other embodiments of the present application. In some other embodiments, before step S200, the pressure relief mechanism manufacturing method 30 further includes:

[0444] Step S150: punching the sheet to form a groove on the sheet;

[0445] Step S200 includes:

[0446] Step S210 : machining a weak portion 2421 on the bottom wall of the groove so that the second portion 2411 extends relative to the weak portion 2421 along the thickness direction of the sheet.

[0447] After step S210 , the sidewall of the groove becomes the second portion 2411 of the pressure relief mechanism 24 .

[0448] By first machining a groove on the sheet and then machining a weak portion 2421 on the bottom wall of the groove, the second portion 2411 can be extended relative to the weak portion 2421 along the thickness direction of the sheet, which is simple and convenient.

[0449] Please refer to Figure 29 , Figure 29 This is a schematic block diagram of a pressure relief mechanism manufacturing method 30 provided in some further embodiments of the present application. In some further embodiments, step S200 includes:

[0450] Step S220: Punching the sheet to form a weak portion 2421 on the sheet.

[0451] By stamping the weak portion 2421 , it is easier to control the thickness of the weak portion 2421 , and the processing accuracy is higher, which is beneficial for ensuring that the bursting pressure of multiple battery cells 20 remains consistent when manufacturing multiple battery cells 20 , and is beneficial for improving the reliability of the battery cells 20 .

[0452] Optionally, in step S220 , the flow direction of the material sheet is controlled so that the first portion 24221 extends relative to the weak portion 2421 along the thickness direction of the material sheet.

[0453] In step S220 , the flow direction of the sheet can be assisted by a support member so that the first portion 24221 extends relative to the weak portion 2421 along the thickness direction of the sheet.

[0454] By controlling the flow direction of the sheet when stamping the weak portion 2421 , the first portion 24221 can be extended relative to the weak portion 2421 along the thickness direction of the sheet, which is simple and convenient.

[0455] The embodiment of the present application further provides a battery device 100 , which includes the above-mentioned battery cell 20 .

[0456] An embodiment of the present application further provides an electrical device, which includes the above-mentioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0457] According to some embodiments of this application, please refer to Figures 3 to 26 .

[0458] An embodiment of the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 23, and a pressure relief mechanism 24. The housing 21 has a wall portion 213, the base material of the wall portion 213 is iron, and the electrode assembly 23 is accommodated in the housing 21. The base material of the pressure relief mechanism 24 is iron. The pressure relief mechanism 24 includes a weak portion 2421, a main body portion 2422, and a connecting portion 241. The weak portion 2421 is configured to be at least partially destroyed to release pressure when the pressure inside the housing 21 reaches a threshold. The main body portion 2422 is located in the area enclosed by the weak portion 2421, and the connecting portion 241 is located outside the weak portion 2421 and connected to the wall portion 213. The portion of the main body 2422 proximate to the weak portion 2421 is the first portion 24221, and the portion of the connecting portion 241 proximate to the weak portion 2421 is the second portion 2411. At least one of the first portion 24221 and the second portion 2411 extends relative to the weak portion 2421 in a direction approaching or away from the electrode assembly 23. By extending at least one of the first portion 24221 and the second portion 2411 relative to the weak portion 2421 in a direction approaching or away from the electrode assembly 23, material flow is facilitated during stamping and forming of the weak portion 2421, which helps to reduce stress in the weak portion 2421. This ensures that the formed weak portion 2421 has greater structural stability and is less likely to develop a concave and convex wavy structure. This helps maintain consistent burst pressure across multiple battery cells 20 during manufacture, thereby improving the reliability of the battery cells 20. Furthermore, when the battery cell 20 expands, the wall portion 213 is deformed under force, and at least one of the first portion 24221 and the second portion 2411 that extends relative to the weak portion 2421 can be stretched under the action of external force, thereby reducing the pulling of the weak portion 2421 by the external force and reducing the risk of the weak portion 2421 being damaged prematurely, which is beneficial to improving the life and reliability of the battery cell 20.

[0459] Both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 in a direction away from the electrode assembly 23. When both the first portion 24221 and the second portion 2411 extend relative to the weak portion 2421 in a direction away from the electrode assembly 23, the first portion 24221 can utilize the extended height of the second portion 2411 to extend. This helps reduce the height of the main body 2422 beyond the surface of the connecting portion 241 farthest from the electrode assembly 23, reduces the space occupied by the battery device 100, and helps improve the energy density of the battery device 100. Furthermore, when the battery cell 20 releases pressure, the first portion 24221 and the second portion 2411 respectively apply opposite forces to the weak portion 2421, subjecting the weak portion 2421 to shear force, facilitating the opening of the weak portion 2421 to release pressure. Under the same blasting pressure, the thickness of the weak portion 2421 can be larger. When the battery cell 20 is in normal use, the weak portion 2421 is not likely to crack prematurely due to pressure changes inside the battery cell 20 or external impact, which is beneficial to reducing the risk of the weak portion 2421 being damaged prematurely and improving the life of the battery cell 20.

[0460] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: The housing has a wall portion, wherein the base material of the wall portion is iron; an electrode assembly housed in the housing; A pressure relief mechanism, the base material is iron, the pressure relief mechanism includes a weak portion, a main body and a connecting portion, the weak portion is configured to be at least partially destroyed to release the pressure when the pressure inside the shell reaches a threshold value, the main body is located in the area surrounded by the weak portion, the connecting portion is located outside the weak portion and is connected to the wall portion, the portion of the main body close to the weak portion is the first portion, and the portion of the connecting portion close to the weak portion is the second portion, and at least one of the first portion and the second portion extends relative to the weak portion in a direction close to or away from the electrode assembly.

2. The battery cell according to claim 1, wherein The difference between the surface roughness of the first portion and the surface roughness of the weak portion is less than or equal to Ra0.3, and / or A difference between the surface roughness of the second portion and the surface roughness of the weak portion is less than or equal to Ra0.

3.

3. The battery cell according to claim 2, wherein: The surface roughness of the weak portion, the surface roughness of the first portion, and the surface roughness of the second portion are the same.

4. The battery cell according to claim 1, wherein: The pressure relief mechanism is provided with a pressure relief groove, and the bottom wall of the pressure relief groove forms the weak portion; The groove side surface of the pressure relief groove and the groove bottom surface of the pressure relief groove are transitioned through rounded corners; and / or The pressure relief mechanism includes a first surface, the pressure relief groove is provided on the first surface, and the groove side surface of the pressure relief groove transitions to the first surface through a rounded corner.

5. The battery cell according to claim 1, wherein: The material of the wall portion includes at least one of stainless steel and carbon steel; the material of the pressure relief mechanism includes at least one of stainless steel and carbon steel.

6. The battery cell according to claim 5, wherein: The material of the wall portion includes at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel; the material of the pressure relief mechanism includes at least one of SU304 stainless steel, SU305 stainless steel or SU316L stainless steel.

7. The battery cell according to claim 1, wherein: The thickness of the main body is H1, which satisfies: 0.05mm≤H1≤0.5mm; and / or The thickness of the connecting portion is H2, which satisfies: 0.05mm≤H2≤0.5mm.

8. The battery cell according to claim 1, wherein: An extension height of at least one of the first portion and the second portion relative to the weak portion ranges from [0.2 mm to 7 mm].

9. The battery cell according to claim 8, wherein: An extension height of at least one of the first portion and the second portion relative to the weak portion ranges from [0.3 mm to 5 mm].

10. The battery cell according to claim 1, wherein The first portion at least partially extends relative to the weakened portion in a direction approaching or away from the electrode assembly.

11. The battery cell according to claim 10, wherein: The entire first portion extends relative to the weakened portion in a direction away from the electrode assembly.

12. The battery cell according to claim 10, wherein: A portion of the first portion extends relative to the weakened portion in a direction away from the electrode assembly.

13. The battery cell according to claim 10, wherein: The electrode assembly includes at least two layers of electrode sheets; The at least two layers of electrode sheets are stacked in a first direction; or the at least two layers of electrode sheets are wound, each of the at least two layers of electrode sheets includes a planar section located in the middle of the electrode assembly and curved sections located at both ends of the electrode assembly, and the at least two layers of electrode sheets are stacked in the first direction in the planar sections; The cross section of the main body portion in at least one plane perpendicular to the first direction is arched.

14. The battery cell according to claim 10, wherein: An extension height of the first portion relative to the weak portion is H3, which satisfies the following conditions: 0.5 mm ≤ H3 ≤ 5 mm.

15. The battery cell according to claim 14, wherein: 0.8mm≤H3≤3mm.

16. The battery cell according to claim 1, wherein The second portion extends relative to the weak portion in a direction approaching or away from the electrode assembly.

17. The battery cell according to claim 16, wherein: The connecting portion includes a third portion, the third portion is used to be connected to the wall portion, and the second portion connects the weak portion and the third portion.

18. The battery cell according to claim 17, wherein: The third portion is parallel to the wall portion.

19. The battery cell according to claim 17, wherein: The second portion is tilted relative to the third portion, and an inclination angle a of the second portion relative to the third portion satisfies the following: 40°≤a≤75°.

20. The battery cell according to claim 1, wherein The first portion and the second portion both extend relative to the weak portion, and a direction in which the first portion extends relative to the weak portion is the same as a direction in which the second portion extends relative to the weak portion.

21. The battery cell according to claim 20, wherein: The first portion and the second portion both extend relative to the weak portion in a direction approaching the electrode assembly.

22. The battery cell according to claim 20, wherein: The first portion and the second portion both extend relative to the weakened portion in a direction away from the electrode assembly.

23. The battery cell according to claim 1, wherein The first portion and the second portion both extend relative to the weak portion, and a direction in which the first portion extends relative to the weak portion is opposite to a direction in which the second portion extends relative to the weak portion.

24. The battery cell according to claim 23, wherein: The first portion extends relative to the weak portion in a direction approaching the electrode assembly, and the second portion extends relative to the weak portion in a direction away from the electrode assembly.

25. The battery cell according to claim 23, wherein The first portion extends relative to the weak portion in a direction away from the electrode assembly, and the second portion extends relative to the weak portion in a direction approaching the electrode assembly.

26. The battery cell according to any one of claims 1 to 25, characterized in that: The minimum thickness of the weak portion is H4, satisfying 0.01mm≤H4≤0.2mm.

27. The battery cell according to claim 26, wherein: The projected area of ​​the main body along the thickness direction of the wall is S; Among them, 100mm 2 ≤450mm 2 , and 0.010mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.015mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.020mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.025mm≤H4≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.030mm≤H4≤0.200mm.

28. The battery cell according to claim 27, wherein: 100mm 2 ≤S≤450mm 2 , and 0.020mm≤H4≤0.160mm; or, 350mm 2 ≤S≤850mm 2 , and 0.025mm≤H4≤0.170mm; or, 750mm 2 ≤S≤1250mm 2 , and 0.030mm≤H4≤0.180mm; or, 1150mm 2 ≤S≤1650mm 2 , and 0.035mm≤H4≤0.190mm; or, 1550mm 2 ≤S≤2100mm 2 , and 0.040mm≤H4≤0.200mm.

29. The battery cell according to any one of claims 1 to 25, characterized in that: The connecting portion is welded to the wall portion.

30. The battery cell according to claim 29, wherein The battery cell further comprises: The support structure is fixed to the side of the wall facing the electrode assembly. The pressure relief mechanism is located on the side of the support structure away from the electrode assembly. The connecting portion is welded to the support structure. The base material of the support structure is iron.

31. The battery cell according to claim 30, wherein The support structure and the wall portion are fixed by welding or bonding.

32. The battery cell according to claim 30, wherein: Along a direction approaching the electrode assembly, the pressure relief mechanism does not extend beyond a surface of the support structure facing the electrode assembly.

33. The battery cell according to claim 30, wherein: The thickness of the support structure is H5, which satisfies: 0.4 mm ≤ H5 ≤ 1.5 mm.

34. The battery cell according to claim 33, wherein: 0.4mm≤H5≤0.8mm.

35. The battery cell according to claim 30, wherein: The pressure relief mechanism, the wall portion and the support structure are connected through a common weld.

36. The battery cell according to any one of claims 1 to 25, characterized in that: The battery cell further comprises: A separator is arranged on the side of the wall portion facing the electrode assembly. Along the direction close to the electrode assembly, the pressure relief mechanism at least partially protrudes from the surface of the wall portion facing the electrode assembly, and the separator protrudes from the surface of the pressure relief mechanism facing the electrode assembly.

37. The battery cell according to claim 36, wherein: The partition comprises a fourth portion and a fifth portion which are spaced apart from each other, and the pressure relief mechanism is located between the fourth portion and the fifth portion.

38. The battery cell according to claim 36, wherein: The partition is provided with an escape opening, and the escape opening is used to escape the pressure relief mechanism.

39. The battery cell according to claim 36, wherein: The separator is provided with a receiving groove opening toward the pressure relief mechanism, the receiving groove is used to receive the pressure relief mechanism, the bottom of the receiving groove is provided with a thinning area corresponding to the pressure relief mechanism, and the thickness of the thinning area is smaller than the thickness of other areas at the bottom of the receiving groove.

40. The battery cell according to any one of claims 1 to 25, characterized in that Along the thickness direction of the wall portion, the pressure relief mechanism does not extend beyond the surface of the wall portion farthest from the electrode assembly in a direction away from the electrode assembly.

41. The battery cell according to any one of claims 1 to 25, characterized in that: The battery cell further includes an electrode terminal, the electrode terminal being disposed on the wall portion, and at least a portion of the electrode terminal protruding from the wall portion in a direction away from the electrode assembly; Along the thickness direction of the wall portion, the pressure relief mechanism does not extend beyond the surface of the electrode terminal farthest from the electrode assembly in a direction away from the electrode assembly.

42. The battery cell according to any one of claims 1 to 25, wherein: The weak portion is in the shape of a closed ring, and the thickness of each portion of the weak portion is the same.

43. The battery cell according to any one of claims 1 to 25, characterized in that: The weak portion is in a closed ring shape and includes a first weak section and a second weak section connected end to end. The thickness of the second weak section is greater than that of the first weak section. The second weak section is located on one side of the weak portion in the length direction of the wall portion.

44. The battery cell according to any one of claims 1 to 25, wherein: The weak portion is open-shaped, and the open end of the weak portion is located on one side of the weak portion in the length direction of the wall portion.

45. The battery cell according to any one of claims 1 to 25, characterized in that: The pressure relief mechanism is provided with a pressure relief groove, and the bottom wall of the pressure relief groove forms the weak portion.

46. ​​The battery cell according to claim 45, wherein The pressure relief groove is formed by stamping.

47. The battery cell according to claim 45, wherein: The cross section of the pressure relief groove is trapezoidal or conical.

48. The battery cell according to claim 45, wherein: Along the width direction of the pressure relief groove, the pressure relief groove includes two groove side surfaces arranged opposite to each other, and the angle between the two groove side surfaces is b, which satisfies: 30°≤b≤90°, optionally, 40°≤b≤80°.

49. A pressure relief mechanism for a battery cell, characterized in that: The base material of the pressure relief mechanism is iron. The pressure relief mechanism includes a weak portion, a main body and a connecting portion. The weak portion is configured to be at least partially destroyed to release the pressure when the pressure inside the battery cell reaches a threshold value. The main body is located in the area surrounded by the weak portion, and the connecting portion is located outside the weak portion. The portion of the main body close to the weak portion is the first portion, and the portion of the connecting portion close to the weak portion is the second portion. At least one of the first portion and the second portion extends relative to the weak portion along the thickness direction of the pressure relief mechanism.

50. A battery device, characterized in that: Comprising a battery cell according to any one of claims 1-48.

51. An electrical device, characterized in that: The battery cell comprises a battery cell according to any one of claims 1 to 48, wherein the battery cell is used to provide electrical energy to the electrical device.

Images