Battery cell, battery, and electrical device

Abstract

The present application provides a battery cell, a battery, and an electrical device. The battery cell comprises a casing and a pressure relief component. The casing comprises a first wall part. The pressure relief component is disposed on the first wall part, and the pressure relief component is provided with a first surface and a second surface which are oppositely arranged in the thickness direction of the first wall part. The pressure relief component is provided with a first groove, the first groove is recessed in a direction from the first surface approaching the second surface, and at least one predetermined pressure relief region is defined by the first groove. The pressure relief component is configured to be capable of cracking along at least part of the first groove when pressure is relieved from the battery cell. The width of the first wall part is W, and the sum of the areas of all of the predetermined pressure relief regions is S, where 10 mm≤W≤100 mm, and 300 mm2≤S≤1500 mm2. The present invention is beneficial for improving the service life and use reliability of a battery cell.

Description

Battery cells, batteries and electrical equipment Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] Batteries are widely used in new energy vehicles, electronic equipment and other fields. As the demand for batteries increases, higher requirements are placed on battery reliability.

[0003] In battery technology, the pressure relief components of battery cells are a key factor affecting their reliability. These components are used to release pressure within the battery cells when the pressure or temperature inside the cells reaches a threshold. However, after repeated cycles and long-term use, these components are prone to premature activation or fatigue cracking, reducing the reliability of the battery cells.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a battery cell, a battery, and an electrical device to improve the reliability of the battery cell.

[0006] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and a pressure relief component; the shell comprises a first wall portion; the pressure relief component is arranged on the first wall portion, and the pressure relief component has a first surface and a second surface arranged opposite to each other in the thickness direction of the first wall portion, and the pressure relief component is provided with a first groove, the first groove is recessed from the first surface toward the direction close to the second surface, and the first groove defines at least one predetermined pressure relief area, and the pressure relief component is configured to be able to split along at least part of the first groove when the battery cell is depressurized; wherein the width of the first wall portion is W, and the sum of the areas of all the predetermined pressure relief areas is S, satisfying: 10mm≤W≤100mm, 300mm2≤S≤1500mm2.

[0007] In the above technical solution, by limiting the width of the first wall to 10 mm to 100 mm and the sum of the areas of all predetermined pressure relief zones to 300 mm² to 1500 mm², the width of the first wall being greater than or equal to 10 mm can reduce the stiffness of the first wall and increase its deformation. This can alleviate the problem of excessive pressure bearing capacity of the bottom wall of the first groove, which results in the pressure relief component requiring an excessively high burst pressure when releasing pressure from the battery cell. This can reduce the risk of battery cell casing rupture, explosion, or fire caused by untimely pressure relief from the pressure relief component, thereby effectively improving the reliability of the battery cell. The width of the first wall being less than or equal to 100 mm can increase the stiffness of the first wall and reduce its deformation. This can alleviate the problem of reduced structural strength of the bottom wall of the first groove of the pressure relief component due to excessive strain and strain amplitude, thereby reducing the risk of leakage caused by premature activation or fatigue cracking of the pressure relief component in the first groove after long-term use of the battery cell. This improves the operational stability of the pressure relief component and facilitates the service life and reliability of the battery cell. And the sum of the areas of all the predetermined pressure relief zones is greater than or equal to 300mm2, which can increase the stress on the predetermined pressure relief zones, and can alleviate the phenomenon that the pressure bearing capacity of the bottom wall of the first groove is too large, resulting in the pressure relief component requiring too large an explosion pressure when the battery cell is relieved, thereby reducing the risk of bursting, explosion, fire, etc. of the battery cell shell due to untimely pressure relief of the pressure relief component, and thus can effectively improve the reliability of the battery cell. The sum of the areas of all the predetermined pressure relief zones is less than or equal to 1500mm2, which can reduce the stress on the predetermined pressure relief zones, thereby reducing the deformation of the first wall, and can alleviate the phenomenon that the structural strength of the bottom wall of the first groove of the pressure relief component is reduced due to excessive strain and strain amplitude, thereby reducing the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component in the first groove after long-term use of the battery cell, so as to further improve the stability of the use of the pressure relief component, which is beneficial to improving the service life and reliability of the battery cell.

[0008] In some embodiments of the first aspect of the present application, 20 mm ≤ W ≤ 80 mm, 400 mm 2 ≤ S ≤ 1200 mm 2 .

[0009] In the above technical solution, by further limiting the width of the first wall portion to 20 mm to 80 mm, wherein the width of the first wall portion is greater than or equal to 20 mm, the stiffness of the first wall portion is further reduced, the deformation of the first wall portion is increased, and the phenomenon of excessive pressure bearing capacity of the bottom wall of the first groove causing the pressure relief component to require an excessively high burst pressure when releasing pressure from the battery cell is further alleviated. This further reduces the risk of bursting, explosion, or fire in the battery cell casing due to untimely pressure relief from the pressure relief component, thereby further effectively improving the reliability of the battery cell. The width of the first wall portion is less than or equal to 80 mm, which further increases the stiffness of the first wall portion and reduces the deformation of the first wall portion. This further alleviates the phenomenon of reduced structural strength of the bottom wall of the first groove of the pressure relief component due to excessive strain and strain amplitude. This further reduces the risk of leakage caused by premature activation or fatigue cracking of the pressure relief component in the first groove after long-term use of the battery cell, thereby further improving the operational stability of the pressure relief component and further improving the service life and reliability of the battery cell. Further limiting the sum of the areas of all predetermined pressure relief zones to between 400 mm² and 1200 mm², with the sum of the areas of all predetermined pressure relief zones being greater than or equal to 400 mm², can further increase the stress on the predetermined pressure relief zones and mitigate the problem of excessive pressure bearing capacity of the bottom wall of the first groove, which results in the pressure relief component requiring an excessively high burst pressure when releasing pressure from the battery cell. This can further reduce the risk of battery cell casing rupture, explosion, or fire caused by untimely pressure relief from the pressure relief component, thereby effectively improving the reliability of the battery cell. The sum of the areas of all predetermined pressure relief zones being less than or equal to 1200 mm² can further reduce the stress on the predetermined pressure relief zones, thereby further reducing deformation of the first wall portion and mitigating the structural strength reduction of the bottom wall of the first groove of the pressure relief component due to excessive strain and strain amplitude. This can further reduce the risk of leakage caused by premature activation or fatigue cracking of the pressure relief component in the first groove after long-term use of the battery cell, thereby further improving the operational stability of the pressure relief component and further improving the service life and reliability of the battery cell.

[0010] In some embodiments of the first aspect of the present application, the pressure relief component further includes a second groove configured to guide the predetermined pressure relief area to open.

[0011] In the above technical solution, the pressure relief component is provided with a second groove, and the pressure relief component forms a weak portion in the area corresponding to the second groove. The weak portion corresponding to the second groove can guide the predetermined pressure relief area to open, thereby improving the opening effect of the predetermined pressure relief area of ​​the pressure relief component, which is beneficial to increasing the pressure relief area of ​​the battery cell after the predetermined pressure relief area is opened. In turn, it can increase the pressure relief rate of the battery cell when thermal runaway occurs, thereby reducing the risk of fire, explosion, connection failure, etc. caused by untimely pressure relief of the battery cell, and is beneficial to improving the reliability of the battery cell. The second groove is provided on the pressure relief component, so that the pressure relief component forms a weak portion in the area corresponding to the second groove and the groove bottom surface of the second groove. Battery cells using this structure facilitate the formation of a weak portion on the pressure relief component, which is beneficial to reducing the difficulty of forming a weak portion on the pressure relief component to guide the predetermined pressure relief area to open, thereby improving the production efficiency of the battery cell 20.

[0012] In some embodiments of the first aspect of the present application, the second groove is recessed from the second surface toward the first surface.

[0013] In the above technical solution, the second groove is recessed from the second surface toward the first surface, and the first groove and the second groove are arranged on opposite sides of the pressure relief component along the thickness direction of the first wall portion, so as to facilitate the processing of the first groove and the second groove on both sides of the pressure relief component along the thickness direction of the first wall portion, respectively, which is beneficial to reduce the mutual influence of the first groove and the second groove during the processing process.

[0014] In some embodiments of the first aspect of the present application, the first surface is a surface of the pressure relief component facing away from the interior of the housing, and the second surface is a surface of the pressure relief component facing the interior of the housing.

[0015] In the above technical solution, by arranging the first and second grooves on the first and second surfaces of the pressure relief component, which are opposite to each other along the thickness direction of the first wall portion, respectively, it is convenient to process the first and second grooves on both sides of the pressure relief component along the thickness direction of the first wall portion, thereby reducing the mutual influence between the first and second grooves during the processing. In addition, the second groove is arranged on the second surface of the pressure relief component facing the interior of the housing, so that the predetermined pressure relief area can be flipped toward the outside of the housing around the bottom wall of the second groove after being opened. This can reduce the interference caused by the groove side of the second groove on the predetermined pressure relief area during the flipping process, thereby improving the flipping effect of the predetermined pressure relief area.

[0016] In some embodiments of the first aspect of the present application, along the thickness direction of the first wall portion, the projection of the first groove and the projection of the second groove do not contact each other.

[0017] In the above technical solution, by setting the projection of the first groove along the thickness direction of the first wall portion and the projection of the second groove along the thickness direction of the first wall portion to a structure that does not contact each other, on the one hand, the mutual influence between the first groove and the second groove during the processing process can be reduced; on the other hand, the phenomenon of the corresponding area of ​​the second groove cracking when the first groove cracks and releases pressure can be reduced, and the stress influence between the first groove and the second groove can be reduced.

[0018] In some embodiments of the first aspect of the present application, the first groove includes a first groove segment and a second groove segment, the first groove segment and the second groove segment are connected, and the first groove segment and the second groove segment jointly define at least one predetermined pressure relief area.

[0019] In the above technical solution, the first groove includes a first groove section and a second groove section, and the first groove section and the second groove section are interconnected structures. On the one hand, it can increase the pressure relief area of ​​the battery cell to increase the pressure relief rate of the battery cell. On the other hand, it makes the position where the first groove section and the second groove section are interconnected weaker, which is easier to crack and open the predetermined pressure relief area to release the internal pressure of the battery cell.

[0020] In some embodiments of the first aspect of the present application, the first groove further includes a third groove segment, the first groove segment and the third groove segment are arranged opposite to each other, the second groove segment connects the first groove segment and the third groove segment, and the first groove segment, the second groove segment and the third groove segment jointly define at least one predetermined pressure relief area.

[0021] In the above technical solution, the first groove is provided with a first groove section and a third groove section arranged opposite to each other, and a second groove section connecting the first groove section and the third groove section, so that the pressure relief component can split along the first groove section, the second groove section and the third groove section when the battery cell is pressure-relieved, so as to open the predetermined pressure relief area to release the internal pressure of the battery cell. The first groove with such a structure makes the intersection position of the first groove section and the second groove section and the intersection position of the second groove section and the third groove section weaker, easier to split and open the predetermined pressure relief area for pressure relief, and can further improve the pressure relief area and pressure relief rate of the battery cell.

[0022] In some embodiments of the first aspect of the present application, the position where the second slot segment is connected to the first slot segment deviates from the two ends of the first slot segment, and the position where the second slot segment is connected to the third slot segment deviates from the two ends of the third slot segment.

[0023] In the above technical solution, the position where the second groove segment is connected to the first groove segment deviates from the two ends of the first groove segment, and the connection position between the first groove segment and the second groove segment is set to be located between the two ends of the first groove segment. The position where the second groove segment is connected to the third groove segment deviates from the two ends of the third groove segment, and the connection position between the third groove segment and the second groove segment is set to be located between the two ends of the third groove segment. The first groove segment, the second groove segment and the third groove segment form an "H"-shaped structure, so that predetermined pressure relief areas can be formed on both sides of the second groove segment of the first groove, and the two predetermined pressure relief areas can be opened in a split manner for pressure relief when the battery cell is depressurized, which is beneficial to further increase the pressure relief effect of the battery cell and can effectively improve the pressure relief rate of the battery cell.

[0024] In some embodiments of the first aspect of the present application, the first groove defines two predetermined pressure relief areas, and the two predetermined pressure relief areas are respectively located on both sides of the second groove section; the pressure relief component also includes a second groove, and the second groove is configured to guide the predetermined pressure relief area to open, and each predetermined pressure relief area corresponds to at least one second groove, and the first groove is located between the two second grooves.

[0025] In the above technical solution, the second groove can guide the corresponding predetermined pressure relief area to open, and at least one second groove is provided corresponding to each predetermined pressure relief area, thereby improving the opening effect of each predetermined pressure relief area of ​​the pressure relief component, which is beneficial to increasing the pressure relief area of ​​the battery cell after the predetermined pressure relief area is opened, and further improving the pressure relief rate of the battery cell when thermal runaway occurs, so as to reduce the risk of fire, explosion, connection failure, etc. caused by untimely pressure relief of the battery cell, and is beneficial to improving the reliability of the battery cell.

[0026] In some embodiments of the first aspect of the present application, the second slot segment and the second groove are arranged opposite to each other along a first direction, and along the first direction, the first slot segment and the third slot segment are both arranged spaced apart from the second groove.

[0027] In the above technical solution, the second groove section and the second groove are arranged opposite each other along the first direction, and the first groove section and the third groove section are spaced apart from the second groove along the first direction. Therefore, the first groove section, the second groove section, and the third groove section do not contact the second groove, which can reduce the mutual influence between the first groove and the second groove during processing, and reduce the phenomenon of cracking in the area corresponding to the second groove when the first groove cracks and releases pressure, and can also reduce the stress effect between the first groove and the second groove. The second groove section and the second groove are arranged opposite each other along the first direction, and the first groove section and the third groove section are spaced apart from the second groove along the first direction. Therefore, the second groove is located between the edge of the first wall portion along the first direction and the first notch. The second groove can act as a buffer between the first groove and the edge of the first wall portion along the first direction, reducing the risk of the first groove cracking due to external force, and improving the reliability of the battery cell.

[0028] In some embodiments of the first aspect of the present application, the first wall portion is a rectangular structure, and the first direction is parallel to the width direction of the first wall portion.

[0029] In the above technical solution, the first direction is parallel to the width direction of the first wall portion, and the second groove section is arranged opposite the second groove along the width direction of the first wall portion. The first groove section and the third groove section are both spaced apart from the second groove along the width direction of the first wall portion, and the first, second, and third groove sections do not contact the second groove along the width direction of the first wall portion. This can reduce the mutual influence between the first and second grooves during processing, reduce the phenomenon that the area corresponding to the first groove causes the area corresponding to the second groove to crack during pressure relief, and reduce the stress effect between the first and second grooves. The second groove section and the second groove are arranged opposite each other along the width direction of the first wall portion, and the first and third groove sections are both spaced apart from the second groove along the width direction of the first wall portion. The second groove is located between the edge of the first wall portion along the width direction of the first wall portion and the first notch. The second groove can act as a buffer between the first groove and the edge of the first wall portion in the first direction, reducing the risk of the first groove cracking due to external forces, and improving the reliability of the battery cell.

[0030] In some embodiments of the first aspect of the present application, the first groove is a multi-level notch groove, and the multi-level notch grooves are arranged sequentially along the direction from the first surface to the second surface. In two adjacent levels of the notch grooves, the first-level notch groove away from the first surface is arranged on the bottom surface of the first-level notch groove close to the first surface.

[0031] In the above technical solution, the first groove is set as a stepped groove structure set along the thickness direction of the wall portion, so that the first groove is a groove formed by multiple processing. When this structure is used to form grooves of the same depth in the pressure relief component, on the one hand, the depth of the single processing of the notched groove can be reduced, which is beneficial to reducing the manufacturing difficulty and demand for manufacturing equipment for forming grooves of the same depth, so as to reduce manufacturing costs, and can reduce the forming force that the pressure relief component is subjected to in a single processing during the formation of the first groove, which is beneficial to reducing the risk of cracks in the pressure relief component, so as to improve the production quality of the battery cell, and on the other hand, it can improve the flow shape of the bottom wall of the first groove during the formation process, which is beneficial to the flow of materials generated when forming the bottom wall of the first groove, so as to improve the structural consistency of the multi-stage notched groove.

[0032] In some embodiments of the first aspect of the present application, the first groove is a three-level scoring groove, and the three-level scoring grooves are arranged in sequence from the first surface to the second surface.

[0033] In the above technical solution, the first groove is a three-level scoring groove. When forming grooves of the same depth, it can reduce the depth of the scoring groove in a single processing, which is beneficial to reducing the manufacturing difficulty and demand for manufacturing equipment for forming grooves of the same thickness, so as to reduce manufacturing costs. It can also reduce the forming force that the pressure relief component is subjected to in a single processing during the formation of the bottom wall of the first groove, which is beneficial to reducing the risk of cracks in the pressure relief component, so as to improve the production quality of the battery cell. On the other hand, it can improve the flow morphology of the bottom wall of the first groove during the formation process, which is beneficial to the flow of materials generated when forming the first groove, so as to improve the structural consistency of the multi-level scoring grooves; it also alleviates the problem of increased processing time due to multiple processing required for the formation of the first groove.

[0034] In some embodiments of the first aspect of the present application, the pressure relief component is integrally formed with the first wall portion.

[0035] In the above technical solution, the pressure relief component and the first wall portion are arranged as an integrally formed structure, so that the pressure relief component is a structure integrated on the first wall portion, that is, the pressure relief component is a wall of the shell, and correspondingly, the pressure relief component is arranged on the first wall portion. The battery cell adopting this structure can improve the structural strength of the pressure relief component arranged on the first wall portion, and can reduce the risk of leakage between the pressure relief component and the first wall portion due to improper assembly.

[0036] In some embodiments of the first aspect of the present application, the pressure relief component is separately provided from the first wall portion, the first wall portion is provided with a pressure relief hole, and the pressure relief component is installed on the first wall portion and covers the pressure relief hole.

[0037] In the above technical solution, by arranging the pressure relief component and the first wall portion as a separate structure, the pressure relief component is a structure installed on the first wall portion. The battery cell adopting this structure can reduce the difficulty of setting the pressure relief component on the first wall portion, and the processing steps of the shell and the pressure relief component can be carried out simultaneously, which is conducive to optimizing the production rhythm of the battery cell.

[0038] In some embodiments of the first aspect of the present application, the battery cell includes an electrode assembly, the electrode assembly is accommodated in the housing, and the first wall portion supports the electrode assembly.

[0039] In the above technical solution, the first wall supports the electrode assembly, and the pressure relief component is arranged on the first wall, which can reduce the risk of the released substance acting on other electrical connection structures when the battery cell is depressurized, thereby reducing the risk of causing other reliability problems.

[0040] In some embodiments of the first aspect of the present application, the battery cell includes an electrode terminal, and the electrode terminal is provided on a wall portion of the housing other than the first wall portion.

[0041] In the above technical solution, the electrode terminals are arranged on other walls of the shell except the first wall, so the risk of the substances discharged from the battery cell when the pressure is released acts on the electrode terminals is low, which can reduce the risk of the battery cell short circuiting and causing thermal runaway of the battery cell again due to the electrical connection formed by the substances discharged from the battery cell when the pressure is released and the electrode terminals.

[0042] In some embodiments of the first aspect of the present application, the electrode terminal is disposed on a wall portion of the housing opposite to the first wall portion.

[0043] In the above technical solution, the electrode terminal is arranged on the wall portion of the shell opposite to the first wall portion, so that the distance between the electrode terminal and the pressure relief component is farther, which can further reduce the risk of the discharged substance of the battery cell acting on the electrode terminal when the battery cell is depressurized, and further reduce the risk of the battery cell short circuit caused by the formation of electrical connection between the discharged substance and the electrode terminal when the battery cell is depressurized, causing the battery cell to short-circuit again and cause thermal runaway of the battery cell.

[0044] In some embodiments of the first aspect of the present application, the housing includes a shell and an end cover; the shell has at least one opening; the end cover corresponds to the opening one by one, the end cover is connected to the shell and closes the opening; wherein the end cover is the first wall portion, or the shell includes the first wall portion.

[0045] In the above technical solution, by configuring the first wall portion of the housing as an end cap for closing the opening of the housing, a battery cell employing this structure facilitates the provision of a pressure relief component on the end cap, thereby reducing the manufacturing difficulty of the battery cell and improving the production efficiency of the battery cell. By configuring the first wall portion of the housing as a wall portion of the shell, a battery cell employing this structure can position the area of ​​the housing where the pressure relief component is provided away from the end cap, thereby effectively alleviating the stress generated by the connection between the end cap and the shell acting on the pressure relief component, thereby reducing the impact on the predetermined pressure relief area of ​​the pressure relief component and the area corresponding to the first groove, thereby facilitating the reduction of the risk of cracking or a decrease in structural strength of the pressure relief component under the pulling effect of stress, thereby improving the service life and reliability of the battery cell.

[0046] In some embodiments of the first aspect of the present application, the shell has two openings arranged opposite to each other; the outer shell includes two end covers, each end cover is connected to the shell and closes one opening, and the shell includes the first wall portion.

[0047] In the above technical solution, the housing has two openings arranged opposite each other, and the two end caps respectively seal the two openings. This structure facilitates assembly of the battery cells from both ends of the housing, which helps reduce the difficulty of manufacturing and assembling the battery cells. The housing includes a first wall portion, and the pressure relief components are not provided on the end caps. This can reduce the risk of substances released from the battery cells during pressure relief from interacting with other battery structures, further reducing the risk of thermal runaway of the battery cells due to the formation of electrical connection between the substances released from the battery cells during pressure relief and the electrode terminals, causing a short circuit in the battery cells.

[0048] In some embodiments of the first aspect of the present application, the shell has an opening, and a wall portion of the shell arranged opposite to the opening is the first wall portion.

[0049] In the above technical solution, the wall portion of the shell that is arranged opposite to the opening is the first wall portion, which can reduce the risk of the substance released when the battery cell is depressurized acting on other structures of the battery, thereby further reducing the risk of the battery cell short circuiting due to the electrical connection formed by the substance released when the battery cell is depressurized and the electrode terminals causing thermal runaway of the battery cell again.

[0050] In some embodiments of the first aspect of the present application, the material of the pressure relief component includes steel.

[0051] In the above technical solution, the pressure relief component is made of steel. Steel has high strength, and the pressure relief component made of steel has better strength. Under the condition of a certain burst pressure of the battery cell, the pressure relief component can be made thinner, reducing the volume of the pressure relief component.

[0052] In some embodiments of the first aspect of the present application, the steel material is carbon steel or stainless steel.

[0053] In the above technical solution, the pressure relief component is made of aluminum alloy. Aluminum alloy has the characteristics of light weight and good ductility, which makes it easier to machine the first groove on the pressure relief component.

[0054] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0055] In a third aspect, an embodiment of the present application further provides an electrical device comprising the above-mentioned battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] 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.

[0057] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0058] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0059] FIG3 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0060] FIG4 is an exploded view of a battery cell provided in some embodiments of the present application;

[0061] FIG5 is a schematic structural diagram of a pressure relief component provided in some embodiments of the present application;

[0062] FIG6 is a cross-sectional view of a pressure relief component provided in some embodiments of the present application;

[0063] FIG7 is an enlarged view of point B1 in FIG6 ;

[0064] FIG8 is a bottom view of a battery cell housing provided in some other embodiments of the present application;

[0065] FIG9 is a bottom view of a battery cell housing provided in some further embodiments of the present application;

[0066] FIG10 is a schematic structural diagram of a battery cell housing provided in yet other embodiments of the present application;

[0067] FIG11 is a bottom view of a battery cell housing provided in some other embodiments of the present application;

[0068] FIG12 is a cross-sectional view taken along the Q1-Q1 direction in FIG11 ;

[0069] FIG13 is an enlarged view of point B2 in FIG12 ;

[0070] FIG14 is an enlarged view of point B3 in FIG12 ;

[0071] FIG15 is a bottom view of a battery cell housing provided in yet other embodiments of the present application;

[0072] FIG16 is a cross-sectional view taken along the line Q2-Q2 in FIG15 ;

[0073] FIG17 is an enlarged view of point B4 in FIG16 ;

[0074] FIG18 is a cross-sectional view taken along the line Q2-Q2 in FIG16 ;

[0075] FIG19 is an enlarged view of point B5 in FIG18 ;

[0076] FIG20 is an enlarged view of point B6 in FIG18 .

[0077] Icon: 1000-vehicle; 100-battery; 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-first wall; 212-housing; 212a-first side wall; 212b-second side wall; 2121-opening; 213-end cover; 22-pressure relief component; 221-first surface; 222-second surface; 223-first groove; 2231-first weak part; 2231a-first weak section; 2232-first groove section; 2233-second groove section; 2234-third groove section; 2235-fourth groove section; 223a-first sub-groove; 22 3a1-first section; 223a2-second section; 223a3-third section; 223b-second sub-groove; 223b1-fourth section; 223b2-fifth section; 223b3-sixth section; 223c-third sub-groove; 223c1-seventh section; 223c2-eighth section; 223c3-ninth section; 224-second groove; 2241-second weak portion; 23-electrode assembly; 231-ear; 24-electrode terminal; 25-current collecting member; 200-controller; 300-motor; P-predetermined pressure relief area; X-thickness direction of the first wall; Y-width direction of the first wall; Z-length direction of the first wall. DETAILED DESCRIPTION

[0078] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0079] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0080] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0081] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0082] In the description of the embodiments of the present application, it should be noted that the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present application. In addition, the terms "first," "second," "third," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0083] 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.

[0084] 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.

[0085] The term "plurality" used in this application refers to two or more (including two).

[0086] 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.

[0087] 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.

[0088] 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 between the positive and negative electrodes while allowing the active ions to pass through.

[0089] 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.

[0090] 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.

[0091] 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.).

[0092] 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 / 3O2 (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 NCM 622 ), 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.

[0093] 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.

[0094] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0095] 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.).

[0096] 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.

[0097] 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.

[0098] As an example, the negative electrode active material may adopt the negative electrode active material for the battery cell 20 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.

[0099] 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.

[0100] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0108] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0109] 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.

[0110] 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.

[0111] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0112] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0113] In some embodiments, the electrode assembly is a laminate structure.

[0114] 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.

[0115] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0116] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded segments that are stacked.

[0117] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0118] 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.

[0119] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] The battery 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.

[0124] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0125] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0126] 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.

[0127] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0128] Batteries, with their outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, are a vital component of today's new energy development. The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered.

[0129] In battery technology, for typical battery cells, to reduce the risk of explosion, fire, and other issues, a pressure relief component can be installed on the battery cell to release the internal pressure of the battery cell through the pressure relief component, thereby reducing the risk of explosion, fire, and other issues in the battery cell and improving the reliability of the battery cell. In related art, the pressure relief component is typically formed on the housing using an integral molding process, that is, integrated into the battery cell housing, or connected to the wall of the housing through welding, clamping, etc., so that when the internal pressure or temperature of the battery cell reaches a threshold, the pressure relief component can be activated and opened to release the internal pressure of the battery cell. However, battery cells are prone to expansion during use or charging and discharging. The expansion force generated by the battery cell acts on the pressure relief component, causing the pressure relief component to be extremely prone to stretching and deformation, resulting in strain and large strain amplitude in the pressure relief component. This reduces the structural strength of the pressure relief component of the battery cell, resulting in poor operational stability of the pressure relief component, and is prone to premature activation or fatigue cracking during use, which is not conducive to improving the service life and reliability of the battery cell.

[0130] Based on the above considerations, in order to alleviate the problem of premature actuation of pressure relief or fatigue cracking of the pressure relief component of the battery cell during use, an embodiment of the present application provides a battery cell, the battery cell including a shell and a pressure relief component; the shell includes a first wall portion; the pressure relief component is arranged on the first wall portion, and the pressure relief component has a first surface and a second surface relatively arranged in the thickness direction of the first wall portion, and the pressure relief component is provided with a first groove, which is recessed from the first surface toward the direction close to the second surface, and the first groove defines at least one predetermined pressure relief area, and the pressure relief component is configured to be able to crack along at least part of the first groove when the battery cell is depressurized; wherein the width of the first wall portion is W, and the sum of the areas of all predetermined pressure relief areas is S, satisfying: 10mm≤W≤100mm, 300mm2≤S≤1500mm2.

[0131] By limiting the width of the first wall portion to 10 mm to 100 mm, wherein the width of the first wall portion is greater than or equal to 10 mm, the rigidity of the first wall portion can be reduced, the deformation of the first wall portion can be increased, and the phenomenon of excessive pressure bearing capacity of the bottom wall of the first groove, which causes the pressure relief component to require an excessively high burst pressure when releasing pressure from the battery cell, can be alleviated. This can reduce the risk of bursting, explosion, or fire in the battery cell casing due to untimely pressure relief from the pressure relief component, thereby effectively improving the reliability of the battery cell. The width of the first wall portion is less than or equal to 100 mm, which can increase the rigidity of the first wall portion, reduce the deformation of the first wall portion, and alleviate the phenomenon of reduced structural strength of the bottom wall of the first groove of the pressure relief component due to excessive strain and strain amplitude. This can also reduce the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component in the first groove after long-term use of the battery cell. This improves the operational stability of the pressure relief component and is conducive to improving the service life and reliability of the battery cell. By limiting the sum of the areas of all predetermined pressure relief zones to between 300 mm² and 1500 mm², where the sum of the areas of all predetermined pressure relief zones is greater than or equal to 300 mm², the stress on the predetermined pressure relief zones can be increased, alleviating the problem of excessive pressure bearing capacity of the bottom wall of the first groove, which results in the pressure relief component requiring an excessively high burst pressure when releasing pressure from the battery cell. This can reduce the risk of battery cell casing rupture, explosion, or fire caused by untimely pressure relief from the pressure relief component, thereby effectively improving the reliability of the battery cell. By limiting the sum of the areas of all predetermined pressure relief zones to less than or equal to 1500 mm², the stress on the predetermined pressure relief zones can be reduced, thereby reducing deformation of the first wall portion and alleviating the problem of reduced structural strength of the bottom wall of the first groove of the pressure relief component due to excessive strain and strain amplitude. This can further reduce the risk of leakage caused by premature activation or fatigue cracking of the pressure relief component in the first groove after long-term use of the battery cell. This further improves the operational stability of the pressure relief component, thereby facilitating the improvement of the service life and reliability of the battery cell.

[0132] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical equipment such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to construct such electrical equipment. This can help alleviate issues such as premature activation of pressure relief components of the battery cells or fatigue cracking during use, thereby improving the reliability and service life of the battery cells.

[0133] The embodiments of the present application provide an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0134] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0135] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 can be arranged at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source or a power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0136] In some embodiments of the present application, the battery 100 can not only serve as the operating power source or usage power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0137] 2 and 3 , FIG2 is an exploded view of a battery 100 according to some embodiments of the present invention, and FIG3 is a schematic structural diagram of a battery cell 20 according to some embodiments of the present invention. The battery 100 includes a housing 10 and a battery cell 20 , wherein the battery cell 20 is accommodated in the housing 10 .

[0138] The housing 10 is used to provide assembly space for the battery cells 20 and can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12. The first housing body 11 and the second housing body 12 cover each other, and the first housing body 11 and the second housing body 12 jointly define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure. The first housing body 11 covers the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define the assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, and the open side of the first housing body 11 covers the open side of the second housing body 12.

[0139] 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 or a cube, etc. For example, in FIG2 , the box body 10 is in the shape of a cuboid.

[0140] In the battery 100, there can be one or more battery cells 20 disposed within the housing 10. When there are multiple battery cells 20 disposed within the housing 10, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel configurations within the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 can be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0141] In some embodiments, the battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which is used to connect the multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20 .

[0142] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be a rectangular parallelepiped, a cylinder, a prism, or other shapes. For example, in FIG3 , the battery cell 20 is a rectangular parallelepiped.

[0143] In some embodiments, as shown in Figures 3 to 7, an embodiment of the present application provides a battery cell 20, which includes a shell 21 and a pressure relief component 22; the shell 21 includes a first wall portion 211; the pressure relief component 22 is arranged on the first wall portion 211, and the pressure relief component 22 has a first surface 221 and a second surface 222 that are relatively arranged in the thickness direction X of the first wall portion, and the pressure relief component 22 is provided with a first groove 223, which is recessed from the first surface 221 toward the direction close to the second surface 222, and the first groove 223 defines at least one predetermined pressure relief area P, and the pressure relief component 22 is configured to be able to split along at least part of the first groove 223 when the battery cell 20 is depressurized; wherein, the width of the first wall portion 211 is W, and the sum of the areas of all predetermined pressure relief areas P is S, satisfying: 10mm≤W≤100mm, 300mm2≤S≤1500mm2.

[0144] 4 , the battery cell 20 may further include an electrode assembly 23, which is housed in the outer shell 21. The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. The structure of the electrode assembly 23 may be various. For example, the electrode assembly 23 may be a wound structure formed by winding a positive electrode sheet, an isolating member, and a negative electrode sheet, or a stacked structure formed by stacking a positive electrode sheet, an isolating member, and a negative electrode sheet.

[0145] Illustratively, the separator is an isolation membrane, and a main material of the isolation membrane may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride.

[0146] The battery cell 20 may include one electrode assembly 23 or multiple electrode assemblies 23. In Figure 4, the battery cell 20 includes two electrode assemblies 23, which are stacked along the thickness of the electrode assemblies 23. The stacking direction of the two electrode assemblies 23 may be the thickness direction of the battery cell 20. Of course, in other embodiments, the number of electrode assemblies 23 included in the battery cell 20 may also be three, four, five, etc.

[0147] In some embodiments, the battery cell 20 further includes an electrolyte contained in the housing 21. The electrolyte may be an electrolytic solution.

[0148] In some embodiments, the housing 21 may include a shell 212 and an end cover 213, and a accommodating cavity is formed inside the shell 212, which is used to accommodate the electrode assembly 23, and the accommodating cavity has at least one opening 2121. That is, the shell 212 is a hollow structure with at least one end opening 2121, and the end cover 213 covers the opening 2121 of the shell 212 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 23 and the electrolyte.

[0149] The first wall portion 211 provided with the pressure relief component 22 may be the end cover 213 of the outer shell 21, or may be a wall portion of the shell 212 of the outer shell 21. For example, in Figures 3 and 4, the first wall portion 211 is the end cover 213. Of course, the structure of the battery cell 20 is not limited thereto. In other embodiments, the first wall portion 211 may also be a wall portion of the shell 212 and the end cover 213 arranged opposite each other, that is, the bottom wall of the shell 212. The first wall portion 211 may also be a side wall of the shell 212 and the end cover 213 that are adjacent to and connected to each other. The side wall may be a wall arranged around the end cover 213 and forming the opening 2121.

[0150] When assembling the battery cell 20 , the electrode assembly 23 may be placed in the housing 212 first, and the housing 212 may be filled with electrolyte. The end cap 213 may then be placed on the opening 2121 of the housing 212 to complete the assembly of the battery cell 20 .

[0151] The shell 212 can be in various shapes, such as a cylinder, a cuboid or a prismatic structure. The shape of the shell 212 can be determined according to the specific shape of the electrode assembly 23. For example, if the electrode assembly 23 is a cylindrical structure, a shell 212 with a cylindrical structure can be selected; if the electrode assembly 23 is a cuboid structure, a shell 212 with a cuboid structure can be selected. Of course, the structure of the end cover 213 can also be various, for example, the end cover 213 is a plate-like structure or a hollow structure with one end open. For example, in Figures 3 and 4, the shell 212 is a cuboid structure, the length direction Z of the first wall portion is the length direction of the battery cell 20, the width direction Y of the first wall portion is the thickness direction of the battery cell 20, and the thickness direction X of the first wall portion is the height direction of the battery cell 20.

[0152] Of course, it is understandable that the shell 21 is not limited to the above structure. The shell 21 may also be other structures. For example, the shell 21 may include a shell body 212 and two end covers 213. The shell body 212 is a hollow structure with openings 2121 formed at both opposite ends. One end cover 213 corresponds to an opening 2121 of the shell body 212 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 23 and the electrolyte. That is, the shell body 212 has openings 2121 on both opposite sides, and the two end covers 213 are respectively covered on both sides of the shell body 212 to close the corresponding openings 2121.

[0153] The housing 21 may be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0154] In some embodiments, the battery cell 20 further includes an electrode terminal 24 . The electrode terminal 24 may be insulated and mounted on the housing 21 , and the electrode terminal 24 is electrically connected to the electrode assembly 23 to output or input electrical energy to the battery cell 20 .

[0155] It should be noted that the electrode terminal 24 is insulated and mounted on the housing 21 , that is, no electrical connection is formed between the electrode terminal 24 and the housing 21 .

[0156] The battery cell 20 may include one or two electrode terminals 24. For example, as shown in FIG4 , the battery cell 20 includes two electrode terminals 24, which are spaced apart along the lengthwise direction Z of the first wall portion. Each electrode assembly 23 has two tabs 231, which are spaced apart along the lengthwise direction Y of the wall portion. The two tabs 231 have opposite polarities, and the two electrode terminals 24 are electrically connected to the two tabs 231 of the electrode assembly 23, respectively, with opposite polarities, to enable input or output of the positive and negative electrodes of the battery cell 20.

[0157] It should be noted that one tab 231 of the electrode assembly 23 can be a component formed by stacking and connecting areas on the positive electrode sheet that are not coated with the positive electrode active material layer, forming a positive tab 231, and the other tab 231 can be a component formed by stacking and connecting areas on the negative electrode sheet that are not coated with the negative electrode active material layer, forming a negative tab 231.

[0158] Exemplarily, the electrode terminal 24 may be made of a variety of materials. For example, the electrode terminal 24 may be made of copper, iron, aluminum, steel, or aluminum alloy.

[0159] There are various locations where the electrode terminals 24 can be mounted on the outer shell 21. For example, in Figures 3 and 4, both electrode terminals 24 are mounted on the end cap 213 of the outer shell 21. Of course, the structure of the battery cell 20 is not limited to this. In the embodiment where the battery cell 20 includes two electrode terminals 24, both electrode terminals 24 can also be mounted on the shell 212 of the outer shell 21. Similarly, one electrode terminal 24 can be mounted on the shell 212 of the outer shell 21, and the other electrode terminal 24 can be mounted on the end cap 213 of the outer shell 21.

[0160] In some embodiments, as shown in Figure 4, the battery cell 20 may also include two current collecting components 25, both of which are arranged in the outer shell 21 and are spaced apart along the length direction Z of the first wall portion. Each current collecting component 25 is used to connect an electrode terminal 24 and a plurality of electrode assemblies 23 with the same polarity in the electrode lugs 231 to achieve electrical connection between the electrode terminal 24 and the electrode assembly 23, which is beneficial to reduce the difficulty of assembly between the electrode lug 231 and the electrode terminal 24.

[0161] Exemplarily, the material of the current collecting member 25 may be various, for example, the material of the current collecting member 25 may be copper, iron, aluminum, steel or aluminum alloy.

[0162] In the embodiment of the present application, the pressure relief component 22 serves to relieve pressure in the battery cell 20 , and is used to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0163] The pressure relief component 22 may have various structures. For example, the pressure relief component 22 may be a separate structure from the first wall portion 211 of the housing 21, or the pressure relief component 22 may be an integral structure with the first wall portion 211 of the housing 21. When the pressure relief component 22 and the first wall portion 211 of the housing 21 are separate structures, that is, the first wall portion 211 of the housing 21 is provided with a pressure relief hole (not shown in the figure) for mounting the pressure relief component 22. The pressure relief component 22 is connected to the first wall portion 211 and covers the pressure relief hole. The pressure relief component 22 and the first wall portion 211 may be connected in various ways, such as welding or clamping. When the pressure relief component 22 and the first wall portion 211 of the outer shell 21 are an integrally formed structure, the pressure relief component 22 is a wall portion of the outer shell 21, that is, the pressure relief component 22 is integrated on the first wall portion 211 and forms a wall of the outer shell 21. Correspondingly, the pressure relief component 22 is a weak structure formed on the first wall portion 211 for cracking when the battery cell 20 releases pressure.

[0164] Exemplarily, the pressure relief component 22 and the first wall portion 211 are an integrally formed structure, that is, the pressure relief component 22 is the first wall portion 211 , and the first weak portion 2231 and the predetermined pressure relief area P are both formed on the first wall portion 211 .

[0165] The first surface 221 and the second surface 222 are two opposing surfaces of the pressure relief component 22 along the thickness direction X of the first wall portion. A first groove 223 is provided on the first surface 221. The pressure relief component 22 forms a first weakened portion 2231 at a location corresponding to the first groove 223. Specifically, the bottom wall of the first groove 223 constitutes the first weakened portion 2231. The bottom wall of the first groove 223 is a portion of the pressure relief component 22. The bottom wall of the first groove 223 is the area of ​​the pressure relief component 22 with the smallest thickness along the thickness direction X of the first wall portion. Therefore, the bottom wall of the first groove 223 is more susceptible to rupture due to increased pressure inside the battery cell 20 than other areas of the pressure relief component 22. The extension path of the first groove 223 represents the rupture path of the pressure relief component 22. After at least a portion of the bottom wall of the first groove 223 ruptures, the pressure relief component 22 can open a predetermined pressure relief area P, allowing the battery cell 20 to release internal pressure from the predetermined pressure relief area P.

[0166] The first groove 223 defines at least one predetermined pressure relief area P, that is, the predetermined pressure relief area P is a portion of the pressure relief component 22. The first groove 223 can define one predetermined pressure relief area P. The first groove 223 can also define multiple predetermined pressure relief areas P, such as two predetermined pressure relief areas P, three predetermined pressure relief areas P, four predetermined pressure relief areas P, etc.

[0167] Depending on the structural shape of the first groove 223, the predetermined pressure relief zone P is formed in different ways. For example, in some embodiments, the first groove 223 forms a closed structure along the extension direction of the first groove 223, and the space enclosed by the first groove 223 is the predetermined pressure relief zone P. For example, as shown in Figures 3-5, the extension trajectory of the first groove 223 is an ellipse, and the first groove 223 defines an elliptical predetermined pressure relief zone P. In this embodiment, the area S of all predetermined pressure relief zones P is the area of ​​the region enclosed by the outer contour of the first groove 223. The outer contour of the first groove 223 is the contour of the edge of the first groove 223 in the width direction closest to the first wall portion 211.

[0168] In other embodiments, the first groove 223 is a non-enclosed structure along its extension direction, and the predetermined pressure relief area P is defined by the first groove 223 and the line connecting the ends of the first groove 223. It should be noted that the line connecting the ends of the first groove 223 is a virtual line. For example, as shown in Figure 8, the first groove 223 is V-shaped along its extension direction. The predetermined pressure relief area P is defined by the V-shaped first groove 223 and the line connecting the two ends of the V-shaped first groove 223. For example, as shown in Figure 9, the first groove 223 is U-shaped along its extension direction. The predetermined pressure relief area P is defined by the U-shaped first groove 223 and the line connecting the two ends of the U-shaped first groove 223. In this case, the sum S of the areas of all predetermined pressure relief areas P is the area enclosed by the outer contour of the first groove 223 and the line connecting the ends of the first groove 223. The dashed lines shown in Figures 8 and 9 are lines connecting the ends of the first groove 223. The dashed line parallel to the second groove 224 in FIG11 is a line connecting the ends of the first groove section 2232 and the third groove section 2234 of the first groove 223 in the direction of their extension. The two dashed lines and the first groove 223 together form two predetermined pressure relief areas P. The dashed line in FIG15 is a line connecting the ends of the first groove section 2232 and the third groove section 2234 of the first groove 223 in the direction of their extension. The two dashed lines and the first groove 223 together form two predetermined pressure relief areas P.

[0169] The first groove 223 includes at least one groove segment. The bottom wall of each groove segment of the first groove 223 forms a corresponding first weak section 2231a. The first weak sections 2231a formed by each groove segment collectively form a first weak portion 2231. It should be noted that each groove segment of the first groove 223 extends along a smooth trajectory, such as a straight line or an arc. The first groove 223 may have one or more groove segments. If the first groove 223 has a straight line, an arc, or an annular structure, the first groove 223 includes only one groove segment, and the first weak portion 2231 formed by the bottom wall of the first groove 223 includes one first weak section 2231a. If the first groove 223 has a "V"-shaped structure, a "U"-shaped structure, or an "H"-shaped structure, the first groove 223 includes multiple groove segments, and the first weak portion 2231 formed by the bottom wall of the first groove 223 includes multiple first weak sections 2231a. For example, in Figures 3-5 , the pressure relief component 22 is provided with a first groove 223, which is an annular groove. The first groove 223 includes a groove segment, and the bottom wall of the first groove 223 forms a first weak portion 2231 including a first weak section 2231a. For another example, as shown in Figure 8 , the pressure relief component 22 is provided with a first groove 223, which includes a first groove segment 2232 and a second groove segment 2233 connected to form a V-shaped first groove 223. The bottom walls of the first groove segment 2232 and the second groove segment 2233 each form a first weak section 2231a. The first weak portion 2231 formed by the bottom wall of the first groove 223 includes two first weak sections 2231a.

[0170] As shown in FIG9 , the pressure relief component 22 is provided with a first groove 223. The bottom wall of the first groove 223 forms a first weak portion 2231. The first groove 223 includes a first groove section 2232, a second groove section 2233, and a third groove section 2234 connected to each other, forming a U-shaped first groove 223. The first groove section 2232 and the third groove section 2234 are arranged opposite each other, and the second groove section 2233 connects to the first groove section 2232. The bottom walls of the first groove section 2232, the second groove section 2233, and the third groove section 2234 each form a first weak portion 2231a. The first groove 223 includes three groove sections, and the first weak portion 2231 formed by the bottom wall of the first groove 223 includes three first weak portions 2231a.

[0171] For another example, in FIG10 , the pressure relief component 22 is provided with a first groove 223, the bottom wall of the first groove 223 forms a first weak portion 2231, the first groove 223 includes a first groove section 2232, a second groove section 2233, a third groove section 2234 and a fourth groove section 2235, the first groove section 2232 and the third groove section 2234 are arranged opposite to each other, the second groove section 2233 connects the first groove section 2232 and the third groove section 2234, the fourth groove section 2235 is located at the first groove section 2232 and the third groove section 2234, and the fourth groove section 2235 is located at the first groove section 2232. Between the first groove section 2232 and the third groove section 2234, and the fourth groove section 2235 is connected to the second groove section 2233, the groove bottom wall of the first groove section 2232, the groove bottom wall of the second groove section 2233, the groove bottom wall of the third groove section 2234 and the groove bottom wall of the fourth groove section 2235 all form a first weak section 2231a, the first groove 223 includes four groove sections, and the first weak portion 2231 formed by the groove bottom wall of the first groove 223 includes four first weak sections 2231a.

[0172] The width W of the first wall portion 211 is the dimension of the first wall portion 211 along the width direction Y of the first wall portion. The dimension W of the first wall portion 211 along the width direction Y of the first wall portion may be the maximum dimension of the first wall portion 211 in the width direction. As shown in FIG10 , in some embodiments, along the width direction Y of the first wall portion, the housing 21 includes a first side wall 212a and a second side wall 212b that are oppositely disposed. The first side wall 212a and the second side wall 212b are respectively connected to both sides of the first wall portion 211 along the width direction. The dimension W of the first wall portion 211 along the width direction may be the distance between the outer surface of the first side wall 212a and the outer surface of the second side wall 212b along the width direction Y of the first wall portion.

[0173] Illustratively, W may be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc.

[0174] Illustratively, S may be 300 mm2, 400 mm2, 500 mm2, 600 mm2, 700 mm2, 800 mm2, 900 mm2, 1000 mm2, 1100 mm2, 1200 mm2, 1300 mm2, 1400 mm2, 1450 mm2, 1500 mm2, etc.

[0175] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to Examples 1-15 and Comparative Examples 1-4. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0176] Example 1

[0177] 1. Preparation of Battery Cell 20

[0178] 1) Preparation of positive electrode

[0179] The positive electrode active material LiNi0.7Co0.1Mn0.1O2, the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) are prepared into a positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the mass ratio of LiNi0.7Co0.1Mn0.1O2, Super P, and PVDF in the solid components is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, it is trimmed, cut into pieces, and divided into strips, and then dried under vacuum conditions at 85°C for 4 hours to make a positive electrode sheet.

[0180] 2) Preparation of negative electrode sheet

[0181] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene-butadiene rubber (SBR) were mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry was 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC, and adhesive styrene-butadiene rubber (SBR) in the solid components was 88:7:3:2. The negative electrode slurry was coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C. Then, it was cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to prepare a negative electrode sheet.

[0182] 3) Preparation of electrolyte

[0183] In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after mixing evenly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0184] 4) Isolation parts

[0185] A 16 μm polyethylene film was used as a separator.

[0186] 5) Preparation of battery cell 20

[0187] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator positioned between the positive and negative electrode sheets to separate them. The electrode assembly 23 is then wound and placed within an aluminum housing 21. The prepared electrolyte is injected into the dried housing 21. The battery cell 20 is then packaged, left to rest, formed, shaped, and subjected to capacity testing, completing the preparation of the battery cell 20. The housing 21 of the battery cell 20 is a rectangular parallelepiped structure. The shell 212 of the housing 21 is open at one end. The wall of the housing 212 opposite the end cap 213 is a first wall 211, which is a rectangular wall. A pressure relief component 22 is provided on the first wall 211 of the housing 21. The first wall 211 and the pressure relief component 22 are integrally formed. The pressure relief component 22 is provided with a first groove 223, with a first weakened portion 2231 formed on the bottom wall of the first groove 223. The first groove 223 has an H-shaped structure and is a three-level notch. The first groove 223 is provided on the outer surface of the first wall portion 211. The sum of the areas S of all predetermined pressure relief areas P of the pressure relief component 22 of the battery cell 20 of Example 1 is 0.0026 mm², and the width dimension W of the first wall portion 211 is 130 mm.

[0188] The preparation methods of the battery cells 20 of Examples 2-7 and Comparative Examples 1-4 are the same as that of Example 1, except that the sum S of the areas of all the predetermined pressure relief areas P and the dimension W of the first wall portion 211 along its width direction are different.

[0189] By performing fatigue tests on the battery cells 20 in Examples 1-7 and Comparative Examples 1-4, the number of fatigue cycles of the battery cells 20 during long-term use is obtained, and by performing thermal runaway tests on the battery cells 20, the breath holding time of the battery cells 20 during thermal runaway is obtained, so as to evaluate the reliability of the battery cells 20, as shown in Table 1.

[0190] The fatigue times of the battery cell 20 are measured as follows:

[0191] 1) Prepare a special test fixture. Specifically, the fixture consists of three 10mm steel plates (first steel plate, second steel plate, and third steel plate). Each steel plate can completely cover the large surface of the battery cell 20 (the large surface of the battery cell 20 refers to the outer surface of the shell 212 perpendicular to the width direction Y along the first wall). The first steel plate and the third steel plate are located at both ends of the fixture and are fixed by bolts. The second steel plate is located between the first steel plate and the third steel plate, and the second steel plate is constrained by a guide rail. The second steel plate can only move horizontally in a direction perpendicular to the plane of the steel plate.

[0192] 2) The battery cell 20 is installed between the first steel plate and the second steel plate, and a support structure is placed between the large surface of one side of the battery cell 20 and the first steel plate, and the large surface of the other side and the second steel plate. The support structure can be an insulation pad or a water-cooling plate (consistent with the material / structure between two adjacent battery cells 20 in the actual battery 100). The support structure can be compressed to provide expansion space for the battery cell 20 during the charge and discharge cycle aging process; the large surface of the battery cell 20 is in contact with the support structure, the first steel plate is in contact with the corresponding support structure, the second steel plate is in contact with the corresponding support structure, and a pressure sensor is provided between the second steel plate and the third steel plate.

[0193] 3) Adjust the position of the second steel plate by adjusting the bolt preload to adjust the initial compressive force on the battery cell 20. Secure a battery cell 20 in a dedicated test fixture, adjust the bolt preload, and observe the pressure sensor until the initial compressive force on the battery cell 20 is 2000N. Then, connect the two electrical connections (positive and negative electrode terminals) of the battery cell 20 to the charging and discharging equipment.

[0194] 4) Place the battery cell 20 and the fixture in a constant temperature environment of 25±2°C, and start the test after the battery cell 20 reaches temperature equilibrium.

[0195] 5) The test steps are carried out in accordance with Section 6.4 "Standard Cycle Life" of "GBT31484-2015 Requirements and Test Methods for 100 Cycle Life of Power Batteries for Electric Vehicles", and the test cycle end condition is changed to "stop testing until the first groove 223 of the pressure relief component 22 is damaged."

[0196] Specifically, test according to the following steps:

[0197] a) Discharge to 2.8V with a current of 1I1(A);

[0198] b) Leave it for no less than 30 minutes;

[0199] c) Charge in accordance with the method 6.1.1.3 of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles;

[0200] d) Leave it for no less than 30 minutes;

[0201] e) Discharge at a current of 1I1(A) until the battery reaches 2.8V;

[0202] f) Repeat steps b) to e) until the first groove 223 of the pressure relief component 22 is damaged and the test is stopped.

[0203] That is, during the test, the area where the first groove 223 of the pressure relief component 22 of the battery cell 20 is located is continuously observed until the area breaks and leaks. The number of cycles is recorded as the cycle fatigue number of the battery cell 20. The greater the number of cycle fatigue numbers of the battery cell 20, the lower the probability of the battery cell 20 opening the valve and leaking liquid due to gas production during long-term use, and the longer the service life.

[0204] The thermal runaway test method for battery cell 20 is as follows:

[0205] 1. Select the heating plate according to the size of the battery cell 20. The size of the heating plate should cover as much of the battery cell 20 as possible (coverage area ≥ 60%);

[0206] 2. Charge the battery cell 20 to 100% SOC before testing and ensure that the temperature of the battery cell 20 is 25±5℃;

[0207] 3. Sensor layout:

[0208] 1) Arrangement of temperature-sensing wires: A layer of Teflon is applied to the center areas of the two large surfaces of the battery cell 20, and a temperature-sensing wire is arranged above the Teflon, followed by another layer of Teflon.

[0209] 2) Layout of voltage sampling line: A layer of Teflon is applied to the positive electrode terminal 24, the negative electrode terminal 24 and the housing 21 of the battery cell 20, a voltage sampling line is arranged above the Teflon, and another layer of Teflon is applied;

[0210] 3) Air pipe arrangement: Drill a hole in the first wall 211 of the housing 21 of the battery cell 20. The hole is located at the center between the edge of the first groove 223 and the side surface of the housing 212 (the outer surface of the wall of the housing 212 adjacent to the first wall 211 along the length direction Z of the first wall) along the length direction Z of the first wall. Insert the air pipe into the hole and seal it. Connect the air pipe to the air pressure sensor.

[0211] 4) Connect the temperature sensing wire, voltage sampling wire and air pressure sensor to the data acquisition instrument to collect and analyze data in real time. The acquisition frequency of the data acquisition instrument is ≤0.1S;

[0212] 4. Assemble the fixture so that it completely covers the large surface of the battery cell 20 (the outer surface of the housing 212 perpendicular to the width direction Y of the first wall), with a clamping force of 3000N. Note: The arrangement order of the fixture, heating plate and battery cell is: fixture + heating plate + battery cell 20 + fixture;

[0213] 5. Testing: Turn on the data acquisition instrument to collect temperature, voltage, and air pressure data, then turn on the heating plate at a power of 500W to heat the battery cell 20 until the battery cell 20 thermally runs away.

[0214] 6. Obtain the pressure holding time of the battery cell 20, determine the thermal runaway moment and valve opening moment based on the temperature, voltage, and air pressure data collected by the data acquisition instrument, and calculate the pressure holding time of the battery cell 20 based on the formula: pressure holding time = valve opening moment - thermal runaway moment.

[0215] Thermal runaway criteria: a) The triggering object generates a voltage drop exceeding 25% of the initial voltage; b) The temperature at the detection point reaches the manufacturer's maximum operating temperature; c) The temperature rise rate dT / dt at the detection point is ≥ 1°C / s and persists for more than 3 seconds. Thermal runaway is determined to have occurred when a) and c) or b) and c) occur, and the moment of thermal runaway is determined.

[0216] Valve opening timing determination: When the air pressure drops by more than 25%, it can be determined that the valve is open (at least partially cracked along the first groove 223). The moment when the air pressure begins to drop is the valve opening time. The valve opening time and thermal runaway time can both be obtained from the data logger.

[0217] Table 1:

[0218] As shown in Table 1, as S gradually increases, the duration of the battery cell 20's holding pressure gradually decreases. Specifically, as S gradually increases, the battery cell 20's timely pressure relief improves, and the risk of explosion during thermal runaway gradually decreases. As S gradually increases, the number of fatigue tests of the battery cell 20 gradually decreases. Specifically, as S gradually increases, the likelihood of the battery cell 20 opening its valve and leaking fluid due to fatigue during long-term use gradually increases.

[0219] As W gradually increases, the duration of the battery cell 20's holding pressure gradually decreases. Specifically, as W gradually increases, the battery cell 20's timely pressure relief improves, and the risk of explosion during thermal runaway gradually decreases. As W gradually increases, the fatigue life of the battery cell 20 gradually decreases. Specifically, as S gradually increases, the likelihood of the battery cell 20 opening its valve and leaking fluid during long-term use gradually increases.

[0220] In Table 1, when W is 3 mm, 5 mm and when S is 100 mm 2 , 200mm 2When W is 10mm, 20mm, 40mm, 60mm, 80mm, 90mm, 100mm, 150mm, 200mm and S is 300mm, the holding time of battery cell 20 is 5.6s and 5.3s respectively, which is much longer than when W is 10mm, 20mm, 40mm, 60mm, 80mm, 90mm, 100mm, 150mm, 200mm and S is 300mm. 2 , 400mm 2 , 500mm 2 , 1000mm 2 , 1200mm 2 , 1400mm 2 , 1500mm 2 , 2000mm 2 , 3000mm 2 The holding time of the battery cell 20 in Comparative Example 1 and Comparative Example 2 when thermal runaway is much longer than the holding time of the battery cell 20 in Examples 1 to 7, Comparative Example 3 and Comparative Example 4 when thermal runaway is greater. Therefore, when W ≥ 10 mm and S ≥ 300 mm 2 When the battery cell 20 is in thermal runaway, the holding time is shorter, which can increase the possibility of timely pressure relief of the pressure relief component 22 of the battery cell 20 and reduce the risk of bursting, explosion, fire, etc. of the outer shell 21 of the battery cell 20 due to untimely pressure relief of the pressure relief component 22.

[0221] When W is 150mm, 200mm and S is 2000mm 2 , 3000mm 2 When W is 100mm, 90mm, 80mm, 60mm, 40mm, 20mm, 10mm, 5mm, 3mm and S is 1500mm, the fatigue times of the battery cell 20 are 904 and 862 respectively, which are much smaller than those when W is 100mm, 90mm, 80mm, 60mm, 40mm, 20mm, 10mm, 5mm, 3mm and S is 1500mm. 2 , 1400mm 2 , 1200mm 2 , 1000mm 2 , 500mm 2 , 400mm 2 , 300mm 2 , 200mm 2 , 100mm 2 The fatigue times of the battery cells in Comparative Examples 3 and 4 are much smaller than those in Examples 1 to 7, Comparative Examples 3 and 4. Therefore, when W≤100mm and when S≤1500mm 2 When the battery cell 20 has a longer fatigue life, the risk of leakage caused by premature activation or fatigue cracking of the pressure relief component 22 in the area corresponding to the first groove 223 after long-term use of the battery cell 20 is reduced.2 ≤S≤1500mm 2 , which can take into account the reduction of risks such as bursting, explosion, and fire of the outer shell 21 of the battery cell 20 due to the untimely pressure relief of the pressure relief component 22, and the reduction of risks of leakage caused by premature activation or fatigue cracking of the pressure relief component 22 at the corresponding position of the first groove 223 of the battery cell 20 after long-term use, thereby improving the use stability of the pressure relief component 22 and improving the service life and reliability of the battery cell 20.

[0222] Therefore, by limiting the width of the first wall portion 211 to 10 mm to 100 mm, wherein the width of the first wall portion 211 is greater than or equal to 10 mm, the stiffness of the first wall portion 211 can be reduced, the deformation of the first wall portion 211 can be increased, and the phenomenon that the pressure-bearing capacity of the bottom wall of the first groove 223 is too large, resulting in excessive bursting pressure required by the pressure relief component 22 when the battery cell 20 is depressurized, can be alleviated, thereby reducing the risk of bursting, explosion, fire, etc. of the outer shell 21 of the battery cell 20 due to untimely pressure relief of the pressure relief component 22, and thus effectively improving the reliability of the battery cell 20. The width of the first wall portion 211 is less than or equal to 100mm, which can increase the rigidity of the first wall portion 211 and reduce the deformation of the first wall portion 211. It can alleviate the phenomenon of reduced structural strength of the bottom wall of the first groove 223 of the pressure relief component 22 due to excessive strain and strain amplitude, thereby reducing the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component 22 in the first groove 223 after long-term use of the battery cell 20, thereby improving the stability of the pressure relief component 22 and helping to improve the service life and reliability of the battery cell 20. And the sum of the areas of all predetermined pressure relief zones P is greater than or equal to 300mm 2 , which can increase the force on the predetermined pressure relief area P, and can alleviate the phenomenon that the pressure-bearing capacity of the bottom wall of the first groove 223 is too large, resulting in the pressure relief component 22 requiring too large a bursting pressure when the battery cell 20 is relieved of pressure, thereby reducing the risk of bursting, explosion, fire, etc. of the battery cell 20 shell 21 due to untimely pressure relief of the pressure relief component 22, thereby effectively improving the reliability of the battery cell 20. The sum of the areas of all predetermined pressure relief areas P is less than or equal to 1500mm 2 , which can reduce the force on the predetermined pressure relief area P, thereby reducing the deformation of the first wall portion 211, and can alleviate the phenomenon that the structural strength of the bottom wall of the first groove 223 of the pressure relief component 22 is reduced due to excessive strain and strain amplitude, thereby reducing the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component in the first groove 223 after long-term use of the battery cell 20, thereby further improving the use stability of the pressure relief component 22, which is beneficial to improving the service life and reliability of the battery cell 20.

[0223] In some embodiments, 20 mm ≤ W ≤ 80 mm, 400 mm 2 ≤S≤1200mm 2 .

[0224] Illustratively, W can be 20 mm, 25 mm, 35 mm, 45 mm, 65 mm, 75 mm, 80 mm, etc.

[0225] For example, S can be 400 mm 2 , 450mm 2 , 550mm 2 、650mm 2 , 750mm 2 , 850mm 2 , 950mm 2 , 1050mm 2 , 1150mm 2 , 1200mm 2 wait.

[0226] Please continue to refer to Table 1. When W is 20mm, 40mm, 60mm, 80mm, 90mm, 100mm, relative to W is 10mm, and when S is 400mm 2 , 500mm 2 , 1000mm 2 , 1200mm 2 , 1400mm 2 , 1500mm 2 When S is 300mm2, the holding time of the battery cell 20 is shorter, that is, the probability of explosion of the battery cell 20 during thermal runaway is lower. Therefore, W≥20mm, S≥400mm 2 When the battery cell 20 is thermally runaway and exploded, the risk can be reduced.

[0227] When W is 10mm, 15mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, relative to W is 90mm, 100mm, and when S is 300mm 2 , 400mm 2 , 450mm 2 , 500mm 2 , 700mm 2 , 1000mm 2 , 1100mm 2 , 1200mm 2 When the relative S is 1400mm 2 , 1500mm 2When the battery cell 20 is used for a long time, the fatigue times of the battery cell 20 are greater, and the probability of the battery cell 20 opening the valve and leaking due to gas production is lower during long-term use, that is, W≤80mm, S≤1200mm 2 When the battery cell 20 is used for a long time, the probability of valve opening and leakage due to gas generation can be reduced.

[0228] In summary, by further limiting the width of the first wall portion 211 to 20 mm to 80 mm, wherein the width of the first wall portion 211 is greater than or equal to 20 mm, the stiffness of the first wall portion 211 can be further reduced, the deformation of the first wall portion 211 can be increased, and the phenomenon that the pressure-bearing capacity of the bottom wall of the first groove 223 is too large, resulting in the pressure relief component 22 requiring too large a bursting pressure when the battery cell 20 is relieved, can be further alleviated, thereby further reducing the risk of bursting, explosion, fire, etc. of the outer shell 21 of the battery cell 20 due to untimely pressure relief of the pressure relief component 22, and further effectively improving the reliability of the battery cell 20. The width of the first wall portion 211 is less than or equal to 80 mm, which can further increase the rigidity of the first wall portion 211 and reduce the deformation of the first wall portion 211. It can further alleviate the phenomenon that the bottom wall of the first groove 223 of the pressure relief component 22 is reduced due to excessive strain and strain amplitude, thereby further reducing the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component 22 in the first groove 223 after long-term use of the battery cell 20, thereby further improving the stability of the pressure relief component 22 and further improving the service life and reliability of the battery cell 20. The sum of the areas of all predetermined pressure relief zones P is further limited to 400 mm. 2 Up to 120mm 2 The sum of the areas of all predetermined pressure relief zones P is greater than or equal to 400mm 2 , which can further increase the force on the predetermined pressure relief area P, and can further alleviate the phenomenon that the pressure-bearing capacity of the bottom wall of the first groove 223 is too large, resulting in the pressure relief component 22 requiring too large a bursting pressure when the battery cell 20 is relieved, thereby further reducing the risk of bursting, explosion, fire, etc. of the battery cell 20 shell 21 due to untimely pressure relief of the pressure relief component 22, thereby further effectively improving the reliability of the battery cell 20. The sum of the areas of all predetermined pressure relief areas P is less than or equal to 1200mm 2, which can further reduce the force on the predetermined pressure relief area P, thereby further reducing the deformation of the first wall portion 211, and can further alleviate the phenomenon of reduced structural strength of the bottom wall of the first groove 223 of the pressure relief component 22 due to excessive strain and strain amplitude, thereby further reducing the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component 22 in the first groove 223 after long-term use of the battery cell 20, thereby further improving the use stability of the pressure relief component 22, which is conducive to further improving the service life and reliability of the battery cell 20.

[0229] In some embodiments, 2000≤S*W≤210000.

[0230] Illustratively, the product of the sum of the areas of all predetermined pressure relief zones P and the width of the first wall portion 211, that is, S*W, can be 2000, 3000, 5250, 8000, 10000, 13500, 20000, 30000, 35000, 40000, 50000, 60000, 70000, 77000, 80000, 90000, 96000, 110500, 100000, 126000, 150000, 200000, 210000, etc.

[0231] The product of the sum of the areas of all predetermined pressure relief areas P and the width of the first wall portion 211 is limited to 2000 to 210000, wherein the product of the sum of the areas of all predetermined pressure relief areas P and the width of the first wall portion 211 is greater than or equal to 2000, so as to alleviate the phenomenon that the pressure bearing capacity of the bottom wall of the first groove 223 is too large, resulting in the pressure relief component 22 requiring too large a bursting pressure when the battery cell 20 is depressurized, thereby reducing the risk of bursting, explosion, fire, etc. of the outer shell 21 of the battery cell 20 due to untimely pressure relief of the pressure relief component 22, thereby effectively improving the reliability of the battery cell 20. The product of the sum of the areas of all the predetermined pressure relief areas P and the width of the first wall portion 211 is less than or equal to 210,000. When the expansion force generated by the expansion of the battery cell 20 during use acts on the pressure relief component 22, the concentration of stress in the first groove 223 can be reduced, and the predetermined pressure relief area P can absorb a portion of the expansion force, thereby effectively alleviating the occurrence of tensile deformation and the like on the bottom wall of the first groove 223 of the pressure relief component 22, thereby reducing the strain and strain amplitude of the bottom wall of the first groove 223 of the pressure relief component 22, that is, reducing the deformation of the bottom wall of the first groove 223, thereby alleviating the phenomenon of reduced structural strength of the bottom wall of the first groove 223 of the pressure relief component 22 due to excessive strain and strain amplitude, thereby reducing the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component 22 in the first groove 223 after long-term use of the battery cell 20, thereby improving the stability of the pressure relief component 22 and facilitating the service life and reliability of the battery cell 20.

[0232] In some embodiments, 3000≤S*W≤150000.

[0233] For example, S*W can be 3000, 15000, 25000, 35000, 45000, 55000, 65000, 75000, 85000, 95000, 115000, 125000, 135000, 145000, 150000, etc.

[0234] The product of the sum of the areas of all the predetermined pressure relief areas P and the width of the first wall portion 211 is further limited to 3000 to 150000, and the product of the sum of the areas of all the predetermined pressure relief areas P and the width of the first wall portion 211 is greater than or equal to 3000. This can further alleviate the phenomenon that the pressure bearing capacity of the bottom wall of the first groove 223 is too large, resulting in excessive bursting pressure required by the pressure relief component 22 when the battery cell 20 is depressurized. This can further reduce the risk of bursting, explosion, fire, etc. of the outer shell 21 of the battery cell 20 due to untimely pressure relief of the pressure relief component 22, and can further effectively improve the reliability of the battery cell 20. The product of the sum of the areas of all the predetermined pressure relief areas P and the width of the first wall portion 211 is less than or equal to 150,000. When the expansion force generated by the expansion of the battery cell 20 during use acts on the pressure relief component 22, the concentration of stress in the first groove 223 can be further reduced, and the predetermined pressure relief area P can absorb a portion of the expansion force, thereby further effectively alleviating tensile deformation and other phenomena of the bottom wall of the first groove 223 of the pressure relief component 22, further reducing the strain and strain amplitude of the bottom wall of the first groove 223 of the pressure relief component 22, that is, reducing the deformation of the bottom wall of the first groove 223, and further alleviating the phenomenon of reduced structural strength of the bottom wall of the first groove 223 of the pressure relief component 22 due to excessive strain and strain amplitude. This further reduces the risk of leakage caused by premature actuation or fatigue cracking of the pressure relief component 22 in the first groove 223 after long-term use of the battery cell 20, thereby improving the operational stability of the pressure relief component 22 and further improving the service life and reliability of the battery cell 20.

[0235] As shown in FIG. 11 , in some embodiments, the pressure relief component 22 further includes a second groove 224 . The second groove 224 is configured to guide the predetermined pressure relief area P to open.

[0236] The bottom wall of the second groove 224 forms a second weak portion 2241 , that is, the pressure relief component 22 is provided with the position of the second groove 224 and the portion of the bottom wall of the second groove 224 corresponding to the second weak portion 2241 .

[0237] Along the thickness direction X of the first wall portion, the thickness of the second weak portion 2241 is greater than the thickness of the first weak portion 2231 formed by the bottom wall of the first groove 223. The second weak portion 2241 is configured to guide the predetermined pressure relief area P to flip when the first weak portion 2231 is cracked to release the internal pressure of the battery cell 20, thereby enabling the second groove 224 to guide the predetermined pressure relief area P to open.

[0238] Among them, the second weak portion 2241 is configured to guide the predetermined pressure relief area P to flip when the bottom wall of the first groove 223 is cracked, that is, the predetermined pressure relief area P can flip with the second weak portion 2241 as the axis after the bottom wall of the first groove 223 of the pressure relief component 22 is cracked, so that after the predetermined pressure relief area P is flipped, the inside of the shell 21 and the outside of the shell 21 are connected to each other and pressure relief is performed.

[0239] Of course, in other embodiments, the second weak portion 2241 may also be other structures. For example, the second weak portion 2241 may be formed by heat treating a part of the pressure relief component 22 to weaken the strength of the area.

[0240] The pressure relief component 22 is provided with a second groove 224. A weakened portion is formed in the area corresponding to the second groove 224. The weakened portion corresponding to the second groove 224 can guide the opening of the predetermined pressure relief area P, thereby improving the opening efficiency of the predetermined pressure relief area P of the pressure relief component 22. This increases the pressure relief area of ​​the battery cell 20 after the predetermined pressure relief area P is opened. This, in turn, increases the pressure relief rate of the battery cell 20 in the event of thermal runaway, thereby reducing the risk of fire, explosion, connection failure, and other issues caused by untimely pressure relief in the battery cell 20, and thus improving the reliability of the battery cell 20. The second groove 224 is provided on the pressure relief component 22, forming a weakened portion in the area corresponding to the bottom surface of the second groove 224. Battery cells 20 employing this structure facilitate the formation of a weakened portion on the pressure relief component 22, thereby reducing the difficulty of forming a weakened portion on the pressure relief component 22 to guide the opening of the predetermined pressure relief area P, thereby improving the production efficiency of the battery cell 20.

[0241] As shown in FIG. 11 to FIG. 14 , in some embodiments, the second groove 224 is recessed from the second surface 222 toward the first surface 221 .

[0242] The first groove 223 is provided on the first surface 221, and the second groove 224 is provided on the second surface 222. The first surface 221 and the second surface 222 are surfaces on opposite sides of the pressure relief component 22 in the thickness direction X of the first wall. The first groove 223 and the second groove 224 are provided on both sides of the pressure relief component 22 along the thickness direction X of the first wall.

[0243] Exemplarily, the first groove 223 is arranged on the surface of the pressure relief component 22 facing away from the interior of the housing 21, and the second groove 224 is arranged on the surface of the pressure relief component 22 facing the interior of the housing 21, so that the first groove 223 and the second groove 224 are respectively arranged on both sides of the pressure relief component 22.

[0244] The second groove 224 is recessed from the second surface 222 toward the first surface 221, and the first groove 223 and the second groove 224 are arranged on opposite sides of the pressure relief component 22 along the thickness direction X of the first wall portion, so as to facilitate the processing of the first groove 223 and the second groove 224 on both sides of the pressure relief component 22 along the thickness direction X of the first wall portion, which is beneficial to reduce the mutual influence of the first groove 223 and the second groove 224 during the processing.

[0245] In some embodiments, the first surface 221 is the surface of the pressure relief component 22 facing away from the interior of the housing 21 , and the second surface 222 is the surface of the pressure relief component 22 facing the interior of the housing 21 .

[0246] That is, the first groove 223 is provided on the surface of the pressure relief component 22 facing away from the interior of the housing 21, and the first groove 223 is recessed from the first surface 221 toward the second surface 222. The second groove 224 is provided on the surface of the pressure relief component 22 facing the interior of the housing 21, and the second groove 224 is recessed from the second surface 222 toward the first surface 221.

[0247] By disposing the first groove 223 and the second groove 224, respectively, on the first surface 221 and the second surface 222 of the pressure relief component 22, which are opposite to each other along the thickness direction X of the first wall, it is convenient to process the first groove 223 and the second groove 224 on both sides of the pressure relief component 22 along the thickness direction X of the first wall, thereby facilitating the reduction of mutual interference between the first groove 223 and the second groove 224 during the processing. Furthermore, by disposing the second groove 224 on the second surface 222 of the pressure relief component 22 facing the interior of the housing 21, the predetermined pressure relief area P, after being opened, can be flipped around the bottom wall of the second groove 224 toward the outside of the housing 21. This can reduce the interference caused by the side surface of the second groove 224 on the predetermined pressure relief area P during the flipping process, thereby improving the flipping effect of the predetermined pressure relief area P.

[0248] In some embodiments, along the thickness direction X of the first wall portion, the projection of the first groove 223 and the projection of the second groove 224 do not contact each other.

[0249] It can be understood that the first groove 223 and the second groove 224 do not intersect.

[0250] By setting the projection of the first groove 223 in the thickness direction X of the first wall portion and the projection of the second groove 224 in the thickness direction X of the first wall portion to a structure that does not contact each other, on the one hand, the mutual influence of the first groove 223 and the second groove 224 during the processing process can be reduced; on the other hand, the phenomenon of the corresponding area of ​​the second groove 224 cracking when the first groove 223 cracks to release pressure can be reduced, and the stress influence between the first groove 223 and the second groove 224 can be reduced.

[0251] Of course, in other embodiments, as shown in FIG. 15 , the pressure relief component 22 may not be provided with the second groove 224 .

[0252] In an embodiment where the first groove 223 includes multiple groove segments, exemplarily, as shown in FIG15 , the first groove 223 includes a first groove segment 2232 and a second groove segment 2233 , the first groove segment 2232 and the second groove segment 2233 are connected, and the first groove segment 2232 and the second groove segment 2233 jointly define at least one predetermined pressure relief area P.

[0253] The first groove section 2232 can extend in a straight line. The second groove section 2233 can extend in a straight line. The first groove section 2232 and the second groove section 2233 together define at least one predetermined pressure relief area P. The predetermined pressure relief area P is configured to be opened when the pressure relief component 22 is ruptured along at least a portion of the bottom wall of the first groove 223 to release pressure within the battery cell 20.

[0254] The first slot section 2232 may also extend along a curve, for example, the first slot section 2232 is an arc section. The second slot section 2233 may also extend along a curve, for example, the second slot section 2233 is an arc section.

[0255] The first slot section 2232 and the second slot section 2233 each form a first weak section 2231a, and the first weak portion 2231 can include two first weak sections 2231a. Because the first slot section 2232 and the second slot section 2233 are connected, the first weak section 2231a formed in the first slot section 2232 and the first weak section 2231a formed in the second slot section 2233 are connected, forming a first weak portion 2231 including the two connected first weak sections 2231a. When one first weak section 2231a begins to crack, it can drive the other first weak section 2231a to crack as well.

[0256] The first groove section 2232 and the second groove section 2233 jointly define a predetermined pressure relief area P, that is, the first groove section 2232 and the second groove section 2233 are structures arranged along the edge of the predetermined pressure relief area P, so that the setting trajectory of the first groove 223 is set along the edge of the predetermined pressure relief area P.

[0257] The predetermined pressure relief area P is configured to be able to be opened when the first weak portion 2231 formed along the bottom wall of at least part of the first groove 223 of the pressure relief component 22 is cracked, that is, when the battery cell 20 undergoes thermal runaway and releases internal pressure, the area of ​​the first groove section 2232 and the second groove section 2233 of the pressure relief component 22 can be cracked, so that the predetermined pressure relief area P can be opened and the internal pressure of the battery cell 20 can be released.

[0258] The first slot segment 2232 and the second slot segment 2233 can be connected in various forms, for example, the first slot segment 2232 and the second slot segment 2233 are connected to form a "T" shape, the first slot segment 2232 and the second slot segment 2233 are connected to form a "V" shape, the first slot segment 2232 and the second slot segment 2233 are connected to form an "L" shape, the first slot segment 2232 and the second slot segment 2233 are connected to form an "X" shape, etc.

[0259] The first groove 223 includes a first groove section 2232 and a second groove section 2233, and the first groove section 2232 and the second groove section 2233 are interconnected structures. On the one hand, they can increase the pressure relief area of ​​the battery cell 20 to increase the pressure relief rate of the battery cell 20. On the other hand, the position where the first groove section 2232 and the second groove section 2233 are interconnected is weaker, which is easier to crack and open the predetermined pressure relief area P to release the internal pressure of the battery cell 20.

[0260] Please continue to refer to Figure 15. In some embodiments, the first groove 223 also includes a third groove section 2234. The first groove section 2232 and the third groove section 2234 are arranged opposite to each other. The second groove section 2233 connects the first groove section 2232 and the third groove section 2234. The first groove section 2232, the second groove section 2233 and the third groove section 2234 jointly define at least one predetermined pressure relief area P.

[0261] The third groove section 2234 can extend in a straight line. The first groove section 2232, the second groove section 2233, and the third groove section 2234 collectively define a predetermined pressure relief area P. The predetermined pressure relief area P is configured to be opened when the first weakened portion formed by the pressure relief component 22 along at least a portion of the bottom wall of the first groove 223 is not broken, thereby releasing the internal pressure of the battery cell 20.

[0262] The extending direction of the first slot segment 2232 is parallel to the extending direction of the third slot segment 2234. The extending direction of the first slot segment 2232 is perpendicular to the extending direction of the second slot segment 2233. The extending direction of the third slot segment 2234 is perpendicular to the extending direction of the second slot segment 2233. In other words, the first slot segment 2232 and the third slot segment 2234 are respectively perpendicular to the second slot segment 2233.

[0263] The first slot segment 2232, the second slot segment 2233 and the third slot segment 2234 can be connected in various forms, for example, the first slot segment 2232, the second slot segment 2233 and the third slot segment 2234 are connected to form an "H" shape, or the first slot segment 2232, the second slot segment 2233 and the third slot segment 2234 are connected to form a "U" shape.

[0264] In other embodiments, the third slot segment 2234 may also extend along a curve, for example, the third slot segment 2234 is an arc segment.

[0265] Among them, the bottom wall of the first groove section 2232, the bottom wall of the second groove section 2233 and the bottom wall of the third groove section 2234 all form a first weak section 2231a, that is, the first weak portion 2231 includes three first weak sections 2231a, and the three first weak sections 2231a are respectively the bottom wall of the first groove section 2232, the bottom wall of the second groove section 2233 and the bottom wall of the third groove section 2234, and the three first weak sections 2231a constitute the first weak portion 2231.

[0266] A first weak section 2231a is formed in the area corresponding to the third slot section 2234, and the first weak portion 2231 includes three first weak sections 2231a. The second slot section 2233 connects the first slot section 2232 and the third slot section 2234. The first weak section 2231a formed in the area corresponding to the second slot section 2233 connects the first weak section 2231a formed in the area corresponding to the first slot section 2232 and the first weak section 2231a formed in the area corresponding to the third slot section 2234. When one of the first weak sections 2231a begins to rupture, it can drive the rupture of another first weak section 2231a, which is conducive to the rapid rupture of the first weak portion 2231 to open the predetermined pressure relief area P and achieve rapid pressure relief.

[0267] The first slot section 2232 and the third slot section 2234 are arranged opposite to each other, that is, the first slot section 2232 and the third slot section 2234 are spaced apart. For example, in FIG15 , the first slot section 2232 and the third slot section 2234 are spaced apart along the length direction Z of the first wall portion, and both the first slot section 2232 and the third slot section 2234 extend along the width direction Y of the first wall portion.

[0268] The second slot section 2233 connects the first slot section 2232 and the third slot section 2234. That is, the second slot section 2233 is located between the first slot section 2232 and the third slot section 2234, and the two ends of the second slot section 2233 are respectively connected to the first slot section 2232 and the third slot section 2234. For example, in FIG15 , the second slot section 2233 extends along the longitudinal direction Y of the wall portion. Of course, in other embodiments, the second slot section 2233 may also extend from the first slot section 2232 and the third slot section 2234 at its two ends in the longitudinal direction Y of the wall portion.

[0269] The first groove 223 is provided with a first groove section 2232 and a third groove section 2234 which are arranged opposite to each other, and a second groove section 2233 connecting the first groove section 2232 and the third groove section 2234, so that the pressure relief component 22 can split along the first groove section 2232, the second groove section 2233 and the third groove section 2234 when the battery cell 20 releases pressure, so as to open the predetermined pressure relief area P to release the internal pressure of the battery cell 20. The first groove 223 with such a structure makes the intersection position of the first groove section 2232 and the second groove section 2233 and the intersection position of the second groove section 2233 and the third groove section 2234 weaker, making it easier to split and open the predetermined pressure relief area P for pressure relief, and can further improve the pressure relief area and pressure relief rate of the battery cell 20.

[0270] As shown in Figure 15, in some embodiments, the position where the second slot segment 2233 is connected to the first slot segment 2232 deviates from the two ends of the first slot segment 2232, and the position where the second slot segment 2233 is connected to the third slot segment 2234 deviates from the two ends of the third slot segment 2234.

[0271] The position where the second slot segment 2233 connects to the first slot segment 2232 deviates from the two ends of the extending direction of the first slot segment 2232. The position where the second slot segment 2233 connects to the third slot segment 2234 deviates from the two ends of the extending direction of the third slot segment 2234.

[0272] Among them, the connection position of the first slot segment 2232 and the second slot segment 2233 deviates from the two ends of the first slot segment 2232, that is, the second slot segment 2233 is connected between the two ends of the first slot segment 2232. Similarly, the connection position of the third slot segment 2234 and the second slot segment 2233 deviates from the two ends of the third slot segment 2234, that is, the second slot segment 2233 is connected between the two ends of the third slot segment 2234, so that the shape of the first groove 223 formed by the first slot segment 2232, the second slot segment 2233 and the third slot segment 2234 is an approximately "H"-shaped structure, and predetermined pressure relief areas P are formed on both sides of the second slot segment 2233. Of course, the areas of the two predetermined pressure relief areas P may be the same or different.

[0273] Exemplarily, the second slot section 2233 is a straight structure extending along the length direction Z of the first wall portion, the first slot section 2232 and the third slot section 2234 are both straight structures extending along the width direction Y of the first wall portion, and the second slot section 2233 is located between the first slot section 2232 and the third slot section 2234 along the length direction Z of the first wall portion.

[0274] By setting the first groove section 2232, the second groove section 2233 and the third groove section 2234 to extend along a straight line, and setting the first groove section 2232 and the third groove section 2234 to be perpendicular to the second groove section 2233, so that the extension direction of the second groove section 2233 is the arrangement direction of the first groove section 2232 and the third groove section 2234, on the one hand, the regularity of the shape of the first groove 223 can be improved, which is conducive to reducing the processing difficulty of the first groove 223, thereby reducing the manufacturing cost of the battery cell 20. On the other hand, the two predetermined pressure relief areas P located on both sides of the second groove section 2233 relieve pressure in opposite directions when the battery cell 20 is relieved.

[0275] The position where the second groove section 2233 is connected to the first groove section 2232 deviates from the two ends of the first groove section 2232, so the connection position of the first groove section 2232 and the second groove section 2233 is set to be located between the two ends of the first groove section 2232, and the position where the second groove section 2233 is connected to the third groove section 2234 deviates from the two ends of the third groove section 2234, so the connection position of the third groove section 2234 and the second groove section 2233 is set to be located between the two ends of the third groove section 2234. The first groove section 2232, the second groove section 2233 and the third groove section 2234 form an "H"-shaped structure, so that both sides of the second groove section 2233 of the first groove 223 can form a predetermined pressure relief area P, and the two predetermined pressure relief areas P can be opened in a split manner for pressure relief when the battery cell 20 is pressure-relieved, which is beneficial to further increase the pressure relief effect of the battery cell 20 and can effectively improve the pressure relief rate of the battery cell 20.

[0276] The first groove 223 can also be other structures. Referring to Figure 9, the shape of the first groove 223 formed by the first groove section 2232, the second groove section 2233 and the third groove section 2234 can be a "U"-shaped structure, that is, one end of the second groove section 2233 is connected to one end of the first groove section 2232, and the other end is connected to one end of the third groove section 2234, so as to form a predetermined pressure relief area P on the pressure relief component 22.

[0277] In some embodiments, the first groove 223 further includes a fourth groove section 2235, which is arranged between the first groove section 2232 and the third groove section 2234. The first four groove sections are connected to the third groove section 2234, and the corresponding areas of the first four groove sections form a first weak section 2231a.

[0278] 15 , the fourth slot segment 2235 intersects the second slot segment 2233 at right angles. The fourth slot segment 2235 extends along the width direction Y of the first wall portion. Along the width direction Y of the first wall portion, the length of the fourth slot segment 2235 is less than the length of the first slot segment 2232, and the length of the fourth slot segment 2235 is less than the length of the third slot segment 2234.

[0279] The bottom wall of the first four trough sections forms a first weak section 2231a. The bottom wall of the first trough section 2232, the bottom wall of the second trough section 2233, the bottom wall of the third trough section 2234 and the bottom wall of the first four trough sections together form a first weak portion 2231 including four first weak sections 2231a.

[0280] The arrangement of the fourth slot section 2235 facilitates the pressure relief component 22 to split from the intersection of the second slot section 2233 and the fourth slot section 2235, thereby enabling the two predetermined pressure relief areas P on both sides of the second slot section 2233 to open synchronously, thereby increasing the pressure relief rate.

[0281] As shown in Figure 15, in some embodiments, the first groove 223 defines two predetermined pressure relief areas P, and the two predetermined pressure relief areas P are respectively located on both sides of the second groove section 2233; the pressure relief component 22 also includes a second groove 224, and the second groove 224 is configured to guide the predetermined pressure relief area P to open. At least one second groove 224 is correspondingly provided for each predetermined pressure relief area P, and the first groove 223 is located between the two second grooves 224.

[0282] Each predetermined pressure relief area P may be provided with one second groove 224 or a plurality of second grooves 224 .

[0283] Each second groove 224 is configured to guide the corresponding predetermined pressure relief area P to flip when the groove bottom wall of the first groove 223 is broken, thereby guiding the predetermined pressure relief area P to open.

[0284] The second groove 224 extends in a direction parallel to the direction of extension of the second groove section 2233 of the first groove 223. The two second grooves 224 are spaced apart along the extending direction of the first groove section 2232 of the first groove 223. The first groove section 2232 and the third groove section 2234 of the first groove 223 are located between the two second grooves 224, and the second groove section 2233 is located between the two second grooves 224, so that the first groove 223 is located between the two second grooves 224.

[0285] Each first groove 223 is located between the edge of the first wall 211 and the first groove 223 along the width direction Y of the first wall. The two first grooves 223 separate the edge of the first wall 211 from the first groove 223 on both sides of the first groove 223 along the width direction Y of the first wall.

[0286] The second groove 224 can guide the corresponding predetermined pressure relief area P to open. At least one second groove 224 is provided corresponding to each predetermined pressure relief area P, thereby improving the opening effect of each predetermined pressure relief area P of the pressure relief component 22, which is beneficial to increasing the pressure relief area of ​​the battery cell 20 after the predetermined pressure relief area P is opened, and further improving the pressure relief rate of the battery cell 20 when thermal runaway occurs, so as to reduce the risk of fire, explosion, connection failure, etc. caused by untimely pressure relief of the battery cell 20, which is beneficial to improving the reliability of the battery cell 20.

[0287] As shown in FIG. 15 , in some embodiments, the second slot segment 2233 and the second groove 224 are disposed opposite to each other along the first direction. Along the first direction, the first slot segment 2232 and the third slot segment 2234 are both spaced apart from the second groove 224 .

[0288] The second groove section 2233 and the second groove 224 are arranged opposite to each other along the first direction, and along the first direction, the first groove section 2232 and the third groove section 2234 are spaced apart from the second groove 224, so the first groove section 2232, the second groove section 2233 and the third groove section 2234 are not in contact with the second groove 224, which can reduce the mutual influence between the first groove 223 and the second groove 224 during the processing, and reduce the phenomenon that the bottom wall of the first groove 223 causes the bottom wall of the second groove 224 to crack when it cracks to release pressure, and can reduce the stress influence between the first groove 223 and the second groove 224. The second groove section 2233 and the second groove 224 are arranged opposite to each other along the first direction, and along the first direction, the first groove section 2232 and the third groove section 2234 are both spaced apart from the second groove 224, so that the second groove 224 is located between the edge of the first wall portion 211 along the first direction and the first notch. The second groove 224 can act as a buffer between the first groove 223 and the edge of the first wall portion 211 in the first direction, thereby reducing the risk of the first groove 223 cracking due to external force and improving the reliability of the battery cell 20.

[0289] Continuing with FIG. 15 , in some embodiments, the first wall portion 211 is a rectangular structure, and the first direction is parallel to the width direction Y of the first wall portion.

[0290] That is, the first groove section 2232 and the third groove section 2234 extend along the width direction Y of the first wall, and the second groove 224 and the second groove section 2233 extend along the length direction Z of the first wall. The second groove 224 and the second groove section 2233 are arranged opposite to each other along the width direction Y of the first wall.

[0291] The first direction is parallel to the width direction Y of the first wall portion, and the second groove section 2233 and the second groove 224 are arranged opposite to each other along the width direction Y of the first wall portion. Along the width direction Y of the first wall portion, the first groove section 2232 and the third groove section 2234 are spaced apart from the second groove 224. The first groove section 2232, the second groove section 2233 and the third groove section 2234 are not in contact with the second groove 224 in the width direction Y of the first wall portion. This can reduce the mutual influence between the first groove 223 and the second groove 224 during the processing, and can reduce the phenomenon that the corresponding area of ​​the first groove 223 causes the corresponding area of ​​the second groove 224 to crack when the pressure is released, and can reduce the stress influence between the first groove 223 and the second groove 224. The second groove section 2233 and the second groove 224 are arranged opposite to each other along the width direction Y of the first wall portion, and along the width direction Y of the first wall portion, the first groove section 2232 and the third groove section 2234 are both spaced apart from the second groove 224, so that the second groove 224 is located between the edge of the first wall portion 211 along the width direction Y of the first wall portion and the first notch. The second groove 224 can act as a buffer between the first groove 223 and the edge of the first wall portion 211 in the first direction, thereby reducing the risk of the first groove 223 cracking due to external force and improving the reliability of the battery cell 20.

[0292] As shown in FIG. 16 and FIG. 17 , along the thickness direction X of the first wall portion, the maximum groove depth of the first groove 223 is H1 , the thickness of the pressure relief component 22 is D, and 0.16≤H1 / D<1.

[0293] H1 / D can take any point value among 0.16, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 0.99, etc., or a range of values ​​between any two of them.

[0294] It is understandable that if the pressure relief component 22 and the first wall portion 211 are integrally formed, the first wall portion 211 can serve as the pressure relief component 22 , and the thickness of the pressure relief component 22 is the same as the thickness of the first wall portion 211 .

[0295] In this embodiment, 0.16≤H1 / D<1, so that the maximum depth of the first groove 223 accounts for a small proportion of the thickness of the pressure relief component 22, and the bursting pressure of the battery cell 20 is not too high, which is conducive to improving the timeliness of the pressure relief of the battery cell 20.

[0296] In some embodiments, 0.4 mm ≤ H1 ≤ 2 mm, and 0.8 mm ≤ D ≤ 2.5 mm.

[0297] H1 can take any point value among 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, etc., or any range value between any two of them.

[0298] D can be any point value among 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, 2.05mm, 2.1mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, 2.35mm, 2.4mm, 2.45mm, 2.5mm, etc., or a range value between any two of them.

[0299] In this embodiment, 0.4 mm ≤ H1 ≤ 2 mm, and 0.8 mm ≤ D ≤ 2.5 mm, keeping the maximum depth of the first groove 223 and the thickness of the pressure relief component 22 within a reasonable range, resulting in better economic efficiency. In an embodiment where the first wall 211 serves as the pressure relief component 22, the thickness of the first wall 211 is 0.8 mm to 2.5 mm. A thickness of 0.8 mm or greater ensures sufficient strength for the first wall 211. A thickness of 2 mm or less ensures that the first wall 211 is not excessively thick. Given a given volume of the housing 21, the internal space of the housing 21 can be increased to create more space for the electrode assembly 23. While maintaining the thickness of the first wall 211 within the range of 0.8 mm to 2.5 mm, the maximum depth of the first groove 223 is controlled within the range of 0.4 mm to 2 mm, ensuring a better match between the maximum depth of the first groove 223 and the thickness of the pressure relief component 22, thereby ensuring that the pressure relief component 22 has good pressure relief capabilities.

[0300] The first groove 223 may be a primary scoring groove.

[0301] As shown in Figures 15-20, in some embodiments, the first groove 223 is a multi-level notch groove. The multi-level notch grooves are arranged sequentially along the direction from the first surface 221 to the second surface 222. In two adjacent notch grooves, the first-level notch groove away from the first surface 221 is arranged at the bottom surface of the first-level notch groove close to the first surface 221.

[0302] That is, the first groove 223 is a multi-step groove structure arranged along the thickness direction X of the first wall portion, that is, the first groove 223 is a step groove structure formed by multiple stamping operations.

[0303] For example, in Figures 15 to 20, the first groove 223 is a three-step groove structure. Of course, in other embodiments, the first groove 223 can also be a two-step groove, a four-step groove, a five-step groove or a six-step groove, etc.

[0304] It should be noted that, in embodiments where the first groove 223 includes multiple groove segments, each groove segment is a multi-step groove structure. For example, in Figures 15-20, the first groove 223 includes a first groove segment 2232, a second groove segment 2233, and a third groove segment 2234. Accordingly, the first groove segment 2232, the second groove segment 2233, and the third groove segment 2234 are all multi-step groove structures. Of course, in the case where the first groove 223 as a whole is a structure such as a curve, a loop, or a straight line extending along a smooth trajectory, the first groove 223 as a whole is a multi-step groove structure. For example, referring to Figures 3 and 4, the first groove 223 is an annular structure. Accordingly, the first groove 223 as a whole is a multi-step groove structure.

[0305] By setting the first groove 223 as a stepped groove structure arranged along the thickness direction of the wall, so that the first groove 223 is a groove formed by multiple processing, when this structure is used to form grooves of the same depth in the pressure relief component 22, on the one hand, the depth of the single processing of the notched groove can be reduced, which is beneficial to reducing the manufacturing difficulty and demand for manufacturing equipment for forming grooves of the same depth, so as to reduce manufacturing costs, and can reduce the forming force that the pressure relief component 22 is subjected to during a single processing during the formation of the first groove 223, which is beneficial to reducing the risk of cracks in the pressure relief component 22, so as to improve the production quality of the battery cell 20, and on the other hand, it can improve the flow shape of the bottom wall of the first groove 223 during the formation process, which is beneficial to the flow of materials generated when forming the bottom wall of the first groove 223, so as to improve the consistency of the structure of the multi-stage notched groove.

[0306] As shown in FIG. 17 , FIG. 19 , and FIG. 10 , in some embodiments, the first groove 223 is a three-level notch groove, and the three-level notch groove is sequentially arranged from the first surface 221 to the second surface 222 .

[0307] The three-level scoring grooves defining the first groove 223 are the first sub-groove 223a, the second sub-groove 223b and the third sub-groove 223c, respectively. The first sub-groove 223a, the second sub-groove 223b and the third sub-groove 223c are arranged in sequence from the first surface 221 to the second surface 222. The second sub-groove 223b is arranged at the bottom surface of the first sub-groove 223a, and the third sub-groove 223c is arranged at the bottom surface of the second sub-groove 223b.

[0308] Exemplarily, as shown in Figures 15 to 20, in an embodiment where the first groove 223 includes a first groove segment 2232, a second groove segment 2233 and a third groove segment 2234, the first sub-groove 223a includes a first segment 223a1, a second segment 223a2 and a third segment 223a3, the second sub-groove 223b includes a fourth segment 223b1, a fifth segment 223b2 and a sixth segment 223b3, and the third sub-groove 223c includes a seventh segment 223c1, an eighth segment 223c2 and a ninth segment 223c3. The fourth section 223b1 is arranged on the bottom surface of the groove of the first section 223a1, the seventh section 223c1 is arranged on the bottom surface of the groove of the fourth section 223b1, and the first section 223a1, the fourth section 223b1 and the seventh section 223c1 together form the first groove section 2232; the fifth section 223b2 is arranged on the bottom surface of the groove of the second section 223a2, the eighth section 223c2 is arranged on the bottom surface of the groove of the fifth section 223b2, the second section 223a2, the fifth section 223b2 and the eighth section 223c2 together form the second groove section 2233; the sixth section 223b3 is arranged on the bottom surface of the groove of the third section 223a3, the ninth section 223c3 is arranged on the bottom surface of the groove of the sixth section 223b3, and the third section 223a3, the sixth section 223b3 and the ninth section 223c3 together form the third groove section 2234.

[0309] The first groove 223 is a three-level scoring groove. When forming grooves of the same depth, it can reduce the depth of the scoring groove in a single processing, which is beneficial to reducing the manufacturing difficulty and demand for manufacturing equipment for forming grooves of the same thickness, thereby reducing manufacturing costs. It can also reduce the forming force that the pressure relief component 22 is subjected to during a single processing during the formation of the bottom wall of the first groove 223, which is beneficial to reducing the risk of cracks in the pressure relief component 22, thereby improving the production quality of the battery cell 20. On the other hand, it can improve the flow shape of the bottom wall of the first groove 223 during the formation process, which is beneficial to the flow of materials generated when forming the first groove 223, thereby improving the structural consistency of the multi-level scoring grooves; it also alleviates the problem of increased processing time due to multiple processing required for the formation of the first groove 223.

[0310] In some embodiments, the pressure relief component 22 is integrally formed with the first wall portion 211 .

[0311] That is to say, the pressure relief component 22 and the first wall portion 211 are an integral structure, and the pressure relief component 22 and the first weak portion 2231 are arranged on the first wall portion 211 using an integral molding process, that is, the pressure relief component 22 is the first wall portion 211, so that the pressure relief component 22 is a part of the outer shell 21.

[0312] For example, in Figure 10 , the first wall portion 211 is the bottom wall of the housing 212, disposed opposite the end cap 213 in the thickness direction X of the first wall portion. The pressure relief component 22 is then the bottom wall, and the first groove 223 is disposed on the bottom wall. If the first wall portion 211 is the end cap 213, the pressure relief component 22 is also the end cap 213, enabling the pressure relief component 22 to seal the opening 2121 of the housing 212, and both electrode terminals 24 are mounted on the pressure relief component 22.

[0313] By setting the pressure relief component 22 and the first wall portion 211 as an integrally formed structure, the pressure relief component 22 is a structure integrated on the first wall portion 211, that is, the pressure relief component 22 is a wall of the outer shell 21, and correspondingly, the pressure relief component 22 is provided on the first wall portion 211. The battery cell 20 adopting this structure can improve the structural strength of the pressure relief component 22 provided on the first wall portion 211, and can reduce the risk of leakage between the pressure relief component 22 and the first wall portion 211 due to improper assembly.

[0314] In some embodiments, the pressure relief component 22 is made of aluminum alloy.

[0315] It is understood that in embodiments where the pressure relief component 22 and the first wall portion 211 are integrally formed, the material of the first wall portion 211 includes an aluminum alloy. If the first wall portion 211 is an end cap 213, the end cap 213 may be made of an aluminum alloy; if the first wall portion 211 is a wall portion within the housing 212, the housing 212 may also be made of an aluminum alloy.

[0316] Aluminum alloy is lightweight and ductile, making it easier to form the first groove 223 on the pressure relief component 22. In the embodiment where the pressure relief component 22 and the first wall portion 211 are integrally formed, the first wall portion 211 is made of aluminum alloy, which can effectively reduce the difficulty of forming the first wall portion 211.

[0317] In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other individual elements ≤ 0.03%.

[0318] This aluminum alloy belongs to the third series aluminum, has lower hardness and better forming ability, reduces the difficulty of processing the first groove 223, is conducive to improving the processing accuracy of the first groove 223, and improves the pressure relief consistency of the pressure relief component 22.

[0319] In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0320] This aluminum alloy belongs to the fifth series aluminum. The pressure relief component 22 made of this aluminum alloy has higher hardness, greater strength and good anti-destruction ability.

[0321] In some embodiments, the pressure relief component 22 is separately provided from the first wall portion 211 . The first wall portion 211 is provided with a pressure relief hole (not shown in the figure). The pressure relief component 22 is installed on the first wall portion 211 and covers the pressure relief hole.

[0322] The pressure relief hole passes through both sides of the first wall portion in the thickness direction X, and the pressure relief hole is communicated with the interior of the housing 21 .

[0323] The pressure relief component 22 and the first wall portion 211 are provided separately. This means that before the pressure relief component 22 and the first wall portion 211 are assembled, the pressure relief component 22 and the first wall portion 211 are two separate components. To complete the assembly of the pressure relief component 22 and the first wall portion 211, the pressure relief component 22 and the first wall portion 211 need to be connected to form a whole. The pressure relief component 22 can be connected to the hole wall of the pressure relief hole and cover the pressure relief hole. For example, the pressure relief component 22 is welded to the first wall portion 211.

[0324] By arranging the pressure relief component 22 and the first wall portion 211 as a separate structure, the pressure relief component 22 is a structure installed on the first wall portion 211. The battery cell 20 adopting this structure can reduce the difficulty of setting the pressure relief component 22 on the first wall portion 211, and the processing steps of the outer shell 21 and the processing steps of the pressure relief component 22 can be carried out simultaneously, which is conducive to optimizing the production rhythm of the battery cell 20.

[0325] In some embodiments, the battery cell 20 includes an electrode assembly 23 . The electrode assembly 23 is accommodated in the housing 21 , and the first wall portion 211 supports the electrode assembly 23 .

[0326] The battery cell 20 may include one or more electrode assemblies 23. In an embodiment where the battery cell 20 includes a plurality of electrode assemblies 23, the plurality of electrode assemblies 23 are stacked along a thickness direction thereof.

[0327] The first wall portion 211 supports the electrode assembly 23 . It can be understood that the first wall portion 211 bears the weight of the electrode assembly 23 .

[0328] The first wall portion 211 supports the electrode assembly 23 , and the pressure relief component 22 is disposed on the first wall portion 211 , which can reduce the risk of substances released when the battery cell 20 releases pressure acting on other electrical connection structures, thereby reducing the risk of causing other reliability issues.

[0329] In some embodiments, the battery cell 20 includes an electrode terminal 24 , which is disposed on other walls of the housing 21 except the first wall 211 .

[0330] The electrode terminal 24 is provided on other walls of the housing 21 except the first wall portion 211 . That is, the electrode terminal 24 and the pressure relief member 22 are provided on different walls of the housing 21 .

[0331] The electrode terminal 24 is arranged on other walls of the shell 21 except the first wall portion 211, so the risk of the substance discharged from the battery cell 20 when the pressure is released acts on the electrode terminal 24 is low, which can reduce the risk of the battery cell 20 short-circuiting due to the substance discharged from the battery cell 20 when the pressure is released and the electrode terminal 24 forming an electrical connection, causing the battery cell 20 to short-circuit and cause thermal runaway of the battery cell 20 again.

[0332] In some embodiments, the electrode terminal 24 is disposed on a wall portion of the housing 21 opposite to the first wall portion 211 .

[0333] Exemplarily, the housing 212 of the outer shell 21 has a bottom wall opposite to the opening 2121. The end cap 213 covers the opening 2121 and is disposed opposite the bottom wall. The bottom wall is the first wall portion 211, and the electrode terminal 24 is disposed on the end cap 213 covering the opening 2121.

[0334] The electrode terminal 24 is arranged on the wall of the shell 21 opposite to the first wall 211, so that the distance between the electrode terminal 24 and the pressure relief component 22 is farther, which can further reduce the risk of the discharged substance of the battery cell 20 acting on the electrode terminal 24 when the pressure is released, and further reduce the risk of the battery cell 20 short-circuiting due to the formation of electrical connection between the discharged substance and the electrode terminal 24 when the pressure is released, causing the battery cell 20 to short-circuit again and cause thermal runaway of the battery cell 20.

[0335] In some embodiments, the housing 21 includes a shell 212 and an end cover 213 ; the shell 212 has at least one opening 2121 ; the end cover 213 corresponds to the opening 2121 one by one, the end cover 213 is connected to the shell 212 and closes the opening 2121 ; wherein the end cover 213 is the first wall portion 211 .

[0336] The end cap 213 is the first wall portion 211, that is, the pressure relief component 22 is disposed on the end cap 213. In an embodiment where the housing 212 has two opposing openings 2121, the housing 21 includes two end caps 213. One of the two end caps 213 can be the first wall, that is, one end cap 213 is provided with the pressure relief component 22, or both end caps 213 can be the first wall, that is, both end caps 213 are provided with the pressure relief component 22.

[0337] By setting the first wall portion 211 of the shell 21 as the end cover 213 of the shell 21 for closing the opening 2121, the battery cell 20 with this structure is convenient for setting the pressure relief component 22 on the end cover 213, which is beneficial to reducing the manufacturing difficulty of the battery cell 20 and improving the production efficiency of the battery cell 20.

[0338] It should be noted that the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 can also have other structures. For example, as shown in Figures 3 and 4, the outer shell 21 may include a shell 212 and an end cover 213. The interior of the shell 212 forms a accommodating cavity with an opening 2121, which is used to accommodate the electrode assembly 23. The end cover 213 closes the opening 2121, and the shell 212 includes a first wall portion 211.

[0339] The shell 212 may include an integrally formed side wall and bottom wall, that is, the shell 212 is manufactured using an integral molding process, such as an integral molding process such as stamping, casting or extrusion molding. In other words, the side wall and bottom wall of the shell 212 are an integral structure.

[0340] The housing 212 includes a first wall portion 211. That is, the first wall portion 211 is a wall of the housing 212. For example, in FIG10 , the first wall portion 211 is a bottom wall of the housing 212 disposed opposite the end cap 213 in the thickness direction X of the first wall portion. Of course, in other embodiments, the first wall portion 211 may also be a side wall of the housing 212.

[0341] By setting the first wall portion 211 of the outer shell 21 as a wall portion of the shell 212, the battery cell 20 adopting this structure can make the area of ​​the outer shell 21 where the pressure relief component 22 is provided away from the end cover 213, thereby effectively alleviating the stress generated by the connection between the end cover 213 and the shell 212 acting on the pressure relief component 22, thereby reducing the impact on the predetermined pressure relief area P of the pressure relief component 22 and the corresponding area of ​​the first groove 223, and thus helping to reduce the risk of cracking or structural strength reduction of the pressure relief component 22 under the pulling action of stress, thereby improving the service life and reliability of the battery cell 20.

[0342] It should be noted that the structure of the battery cell 20 can be various. In some embodiments, the shell 212 has two openings 2121 arranged opposite to each other; the outer shell 21 includes two end covers 213, each end cover 213 is connected to the shell 212 and closes an opening 2121, and the shell 212 includes a first wall portion 211.

[0343] The housing 212 defines an interior housing cavity, and both openings 2121 communicate with the housing cavity. The two openings 2121 may be arranged relative to each other along the thickness direction X of the first wall portion. In an embodiment where the housing 21 includes two openings 2121 and two end caps 213 , the first wall portion 211 may also be a wall of the housing 212 .

[0344] The shell 212 of the outer casing 21 has two openings 2121 arranged opposite each other, and the two end caps 213 respectively seal the two openings 2121. This structure of the battery cell 20 facilitates assembly of the battery cell 20 from both ends of the shell 212, thereby reducing the difficulty in manufacturing and assembling the battery cell 20. The shell 212 includes a first wall portion 211, and the pressure relief component 22 is not provided on the end cap 213. This can reduce the risk of substances released from the battery cell 20 during pressure relief from the battery cell 20 interacting with other structures of the battery 100. This further reduces the risk of substances released from the battery cell 20 during pressure relief from the battery cell 20 interacting with the electrode terminals 24 to form an electrical connection, thereby causing a short circuit in the battery cell 20 and further leading to thermal runaway of the battery cell 20.

[0345] In the embodiment where the housing 21 includes two openings 2121 and two end covers 213, the two end covers 213 respectively close the two openings 2121, and one of the two end covers 213 is a first wall portion 211. Of course, both end covers 213 may be first wall portions 211, and each first wall portion 211 may be provided with a pressure relief component 22.

[0346] In some embodiments, the housing 212 has an opening 2121 , and a wall portion of the housing 212 opposite to the opening 2121 is the first wall portion 211 .

[0347] Illustratively, the wall of the housing 212 opposite to the opening 2121 is the bottom wall of the housing 212 , the bottom wall is the first wall 211 , the end cover 213 is disposed opposite to the first wall 211 , and the electrode terminal 24 is disposed on the end cover 213 .

[0348] The wall portion of the shell 212 that is arranged opposite to the opening 2121 is the first wall portion 211, which can reduce the risk of the substance discharged from the battery cell 20 when the pressure is released to act on other structures of the battery 100, thereby further reducing the risk of the battery cell 20 short-circuiting due to the substance discharged from the battery cell 20 when the pressure is released to form an electrical connection with the electrode terminal 24, causing the battery cell 20 to short-circuit and cause thermal runaway of the battery cell 20 again.

[0349] In some embodiments, the pressure relief component 22 is made of steel.

[0350] The steel material can be carbon steel, alloy steel, stainless steel, etc.

[0351] It is understood that in the embodiment where the pressure relief component 22 and the first wall portion 211 are integrally formed, the material of the first wall portion 211 includes steel. If the first wall portion 211 is an end cap 213, the end cap 213 can be made of steel; if the first wall portion 211 is a wall portion in the housing 212, the housing 212 can be made of steel.

[0352] In this embodiment, steel has the characteristic of high strength, and the pressure relief component 22 made of steel has greater strength. Under the condition of a constant burst pressure of the battery cell 20, the pressure relief component 22 can be made thinner, thereby reducing the volume of the pressure relief component 22. In the embodiment where the pressure relief component 22 is integrally formed with the first wall portion 211, the first wall portion 211 is made of steel and can be made thinner. Under the condition of a constant volume of the outer shell 21, the volume of the outer shell 21 can be increased to provide more space for the electrode assembly 23, which is conducive to improving the volumetric energy density of the battery cell 20.

[0353] In some embodiments, the steel material is carbon steel or stainless steel.

[0354] Carbon steel can be low carbon steel, medium carbon steel or high carbon steel.

[0355] In some embodiments, the pressure relief component 22 is made of aluminum alloy.

[0356] It is understood that in embodiments where the pressure relief component 22 and the first wall portion 211 are integrally formed, the material of the first wall portion 211 includes an aluminum alloy. If the first wall portion 211 is an end cap 213, the end cap 213 may be made of an aluminum alloy; if the first wall portion 211 is a wall portion within the housing 212, the housing 212 may also be made of an aluminum alloy.

[0357] Aluminum alloy is lightweight and ductile, making it easier to machine the first groove 223 and the second groove 224 in the pressure relief component 22. In embodiments where the pressure relief component 22 and the first wall portion 211 are integrally formed, the first wall portion 211 is made of aluminum alloy, effectively reducing the difficulty of forming the first wall portion 211. Due to the excellent ductility of aluminum alloy, it is easier to deposit material in the predetermined pressure relief area P when forming the first groove 223.

[0358] In some embodiments, the present application further provides a battery 100 , which includes the battery cell 20 provided in any of the above embodiments.

[0359] As shown in FIG. 2 , the battery 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0360] In some embodiments, the box body 10 may include a first box body 11 and a second box body 12 . 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 an assembly space for accommodating the battery cells 20 .

[0361] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure, and 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 an assembly 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.

[0362] 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 or a rectangular parallelepiped, etc. For example, in FIG2 , the box body 10 is a rectangular parallelepiped structure.

[0363] Optionally, the number of battery cells 20 disposed in the housing 10 may be one or more. For example, in FIG2 , the housing 10 of the battery 100 includes multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a configuration in which multiple battery cells 20 are connected in both series and parallel. Multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed in the housing 10. Alternatively, the battery 100 may be a module formed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid configuration, and then the multiple battery modules 100 are then connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed in the housing 10.

[0364] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component that connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0365] It should be noted that in some embodiments, the battery 100 may not be provided with a housing 10. The battery 100 includes multiple battery cells 20, and the battery 100 composed of multiple battery cells 20 can be directly assembled on an electrical device to provide electrical energy to the electrical device through the multiple battery cells 20. In other words, the housing 10 can serve as part of the electrical device. Taking the vehicle 1000 as an example of an electrical device, the housing 10 can serve as part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can form at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 can form at least a portion of the crossbeam or longitudinal beam of the vehicle 1000.

[0366] In some embodiments, the present application further provides an electrical device, which includes the battery cell 20 provided in any of the above embodiments.

[0367] The battery cell 20 is used to provide power to an electrical device, wherein the electrical device can be any of the aforementioned devices or systems using the battery cell 20 .

[0368] The present application provides a battery cell 20, which includes a housing 21, an electrode assembly 23, and a pressure relief component 22. The housing 21 has a first wall portion 211, and includes a shell 212 and an end cap 213. The interior of the shell 212 forms a receiving cavity with an opening 2121, and the electrode assembly 23 is received in the receiving cavity. The end cap 213 closes the opening 2121, and the end cap 213 serves as the first wall portion 211. The pressure relief component 22 is a separate structure from the first wall portion 211, and the pressure relief component 22 is disposed on the first wall portion 211.

[0369] Along the thickness direction X of the first wall portion, the pressure relief component 22 has a first surface 221 and a second surface 222 that are oppositely disposed. The first surface 221 is located on the side of the pressure relief component 22 facing away from the interior of the housing 21, while the second surface 222 is located on the side of the pressure relief component 22 facing the interior of the housing 21. The first surface 221 of the pressure relief component 22 is provided with a first groove 223. The first groove 223 comprises a three-level scoring groove, arranged sequentially from the first surface 221 to the second surface 222. The first groove 223 defines two predetermined pressure relief areas P. The pressure relief component 22 is configured to rupture along at least a portion of the first groove 223 when pressure is released from the battery cell 20. The second surface 222 is provided with a second groove 224. Along the thickness direction X of the first wall portion, the bottom wall of the second groove 224 is thicker than the bottom wall of the first groove 223. The second groove 224 is configured to guide the predetermined pressure relief areas P to flip when the first groove 223 ruptures, thereby releasing internal pressure from the battery cell 20.

[0370] The first groove 223 includes a first groove section 2232, a second groove section 2233, a third groove section 2234, and a fourth groove section 2235. The first groove section 2232, the second groove section 2233, the third groove section 2234, and the fourth groove section 2235 each form a first weak section 2231a. The first groove section 2232 and the third groove section 2234 are spaced apart from each other along the length direction Z of the first wall portion. Both the first groove section 2232 and the third groove section 2234 extend in a straight line along the width direction Y of the first wall portion. The third groove section 2234 extends in a straight line along the length direction Z of the first wall portion. The second groove section 2233 connects the first groove section 2232 and the third groove section 2234. The connection between the second groove section 2233 and the first groove section 2232 is located between the two ends of the first groove section 2232, and the connection between the second groove section 2233 and the third groove section 2234 is located between the two ends of the third groove section 2234. The first, second, and third groove sections 2232, 2233, and 2234 form an H-shaped first groove 223. Along the width direction Y of the first wall portion, a predetermined pressure relief area P is formed on either side of the second groove section 2233. The first groove 223 defines two predetermined pressure relief areas P. The fourth groove section 2235 is located between the first and third groove sections 2232, 2234, and intersects with the second groove section 2233.

[0371] The width of the first wall portion 211 is W, and the sum of the areas of all predetermined pressure relief zones P is S, which satisfies the following conditions: 10 mm ≤ W ≤ 100 mm, 300 mm 2 ≤S≤1500mm 2 , preferably, 20mm≤W≤80mm, 400mm 2 ≤S≤1200mm 2 .

[0372] The present application provides a battery cell 20, which includes a housing 21, an electrode assembly 23, and a pressure relief component 22. The housing 21 has a first wall portion 211, and includes a shell 212 and an end cap 213. The interior of the shell 212 forms a receiving cavity with an opening 2121, and the electrode assembly 23 is received in the receiving cavity. The end cap 213 closes the opening 2121, and the end cap 213 forms the first wall portion 211. The pressure relief component 22 is integrally formed with the first wall portion 211 and is disposed on the first wall portion 211.

[0373] Along the thickness direction X of the first wall portion, the pressure relief component 22 has a first surface 221 and a second surface 222 that are oppositely disposed. The first surface 221 is located on the side of the pressure relief component 22 facing away from the interior of the housing 21, while the second surface 222 is located on the side of the pressure relief component 22 facing the interior of the housing 21. The first surface 221 of the pressure relief component 22 is provided with a first groove 223. The first groove 223 comprises a three-level scoring groove, arranged sequentially from the first surface 221 to the second surface 222. The first groove 223 defines two predetermined pressure relief areas P. The pressure relief component 22 is configured to rupture along at least a portion of the first groove 223 when pressure is released from the battery cell 20. The second surface 222 is provided with a second groove 224. Along the thickness direction X of the first wall portion, the bottom wall of the second groove 224 is thicker than the bottom wall of the first groove 223. The second groove 224 is configured to guide the predetermined pressure relief areas P to flip when the first groove 223 ruptures, thereby releasing internal pressure from the battery cell 20.

[0374] The first groove 223 includes a first groove section 2232, a second groove section 2233, a third groove section 2234, and a fourth groove section 2235. The first groove section 2232, the second groove section 2233, the third groove section 2234, and the fourth groove section 2235 each form a first weak section 2231a. The first groove section 2232 and the third groove section 2234 are spaced apart from each other along the length direction Z of the first wall portion. Both the first groove section 2232 and the third groove section 2234 extend in a straight line along the width direction Y of the first wall portion. The third groove section 2234 extends in a straight line along the length direction Z of the first wall portion. The second groove section 2233 connects the first groove section 2232 and the third groove section 2234. The connection between the second groove section 2233 and the first groove section 2232 is located between the two ends of the first groove section 2232, and the connection between the second groove section 2233 and the third groove section 2234 is located between the two ends of the third groove section 2234. The first, second, and third groove sections 2232, 2233, and 2234 form an H-shaped first groove 223. Along the width direction Y of the first wall portion, a predetermined pressure relief area P is formed on either side of the second groove section 2233. The first groove 223 defines two predetermined pressure relief areas P. The fourth groove section 2235 is located between the first and third groove sections 2232, 2234, and intersects with the second groove section 2233.

[0375] The width of the first wall portion 211 is W, and the sum of the areas of all predetermined pressure relief zones P is S, which satisfies the following conditions: 10 mm ≤ W ≤ 100 mm, 300 mm 2 ≤S≤1500mm 2 , preferably, 20mm≤W≤80mm, 400mm 2 ≤S≤120mm 2 .

[0376] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. 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, comprising: A housing including a first wall portion; A pressure relief component disposed on the first wall portion, the pressure relief component having a first surface and a second surface oppositely disposed in the thickness direction of the first wall portion, the pressure relief component being provided with a first groove that recesses from the first surface toward the direction close to the second surface, the first groove defining at least one predetermined pressure relief area, and the pressure relief component being configured to be able to crack along at least part of the first groove when the battery cell relieves pressure; Wherein, the width of the first wall portion is W, and the sum of the areas of all the predetermined pressure relief areas is S, satisfying: 10 mm ≤ W ≤ 100 mm, 300 mm 2 ≤ S ≤ 1500 mm 2 .

2. The battery cell according to claim 1, wherein, 20mm ≤ W ≤ 80mm, 400mm 2 ≤ S ≤ 1200mm 2 。 3. The battery cell according to claim 1 or 2, wherein, The pressure relief component further includes a second groove configured to guide the opening of the predetermined pressure relief area.

4. The battery cell according to claim 3, wherein, The second groove recesses from the second surface toward the direction close to the first surface.

5. The battery cell according to claim 3 or 4, wherein, The first surface is the surface of the pressure relief component facing away from the interior of the housing, and the second surface is the surface of the pressure relief component facing the interior of the housing.

6. The battery cell according to any one of claims 3-5, wherein, In the thickness direction of the first wall portion, the projections of the first groove and the second groove do not contact each other.

7. The battery cell according to any one of claims 1-6, wherein, The first groove includes a first groove section and a second groove section, the first groove section and the second groove section are connected, and the first groove section and the second groove section jointly define at least one of the predetermined pressure relief areas.

8. The battery cell according to claim 7, wherein, The first groove further includes a third groove section, the first groove section and the third groove section are oppositely disposed, the second groove section connects the first groove section and the third groove section, and the first groove section, the second groove section, and the third groove section jointly define at least one of the predetermined pressure relief areas.

9. The battery cell according to claim 8, wherein, The position where the second groove section is connected to the first groove section deviates from both ends of the first groove section, and the position where the second groove section is connected to the third groove section deviates from both ends of the third groove section.

10. The battery cell according to claim 8 or 9, wherein, The first groove defines two of the predetermined pressure relief areas, and the two predetermined pressure relief areas are respectively located on both sides of the second groove section; The pressure relief component further includes a second groove configured to guide the opening of the predetermined pressure relief area, at least one of the second grooves is correspondingly provided for each of the predetermined pressure relief areas, and the first groove is located between the two second grooves.

11. The battery cell according to claim 10, wherein, The second groove section is oppositely disposed to the second groove in a first direction, and in the first direction, both the first groove section and the third groove section are spaced apart from the second groove.

12. The battery cell according to claim 11, wherein, The first wall portion is a rectangular structure, and the first direction is parallel to the width direction of the first wall portion.

13. The battery cell according to any one of claims 1-12, wherein, The first groove is a multi-stage scoring groove, and the multi-stage scoring grooves are sequentially arranged in the direction from the first surface to the second surface. In two adjacent stages of the scoring grooves, the scoring groove of the stage farther from the first surface is disposed on the groove bottom surface of the scoring groove of the stage closer to the first surface.

14. The battery cell according to claim 13, wherein, The first groove is a three-stage scoring groove, and the three-stage scoring grooves are sequentially arranged in the direction from the first surface to the second surface.

15. The battery cell according to any one of claims 1-14, wherein, The pressure relief component is integrally formed with the first wall portion.

16. The battery cell according to any one of claims 1-15, wherein, The pressure relief component is separately disposed from the first wall portion, the first wall portion is provided with a pressure relief hole, and the pressure relief component is installed on the first wall portion and covers the pressure relief hole.

17. The battery cell according to any one of claims 1-16, wherein, The battery cell includes an electrode assembly, the electrode assembly is accommodated in the housing, and the first wall portion supports the electrode assembly.

18. The battery cell according to any one of claims 1-17, wherein, The battery cell includes electrode terminals, and the electrode terminals are disposed on walls of the housing other than the first wall portion.

19. The battery cell according to claim 18, wherein, The electrode terminals are disposed on the wall of the housing opposite to the first wall portion.

20. The battery cell according to any one of claims 1-19, wherein, The housing includes: a housing body having at least one opening; end caps corresponding to the openings one by one, the end caps being connected to the housing body and closing the openings; wherein, the end cap is the first wall portion, or the housing body includes the first wall portion.

21. The battery cell according to claim 20, wherein, The housing body has two openings disposed opposite to each other; the housing includes two end caps, each end cap being connected to the housing body and closing one of the openings, and the housing body includes the first wall portion.

22. The battery cell according to claim 20, wherein, The housing body has one opening, and the wall of the housing body opposite to the opening is the first wall portion.

23. The battery cell according to any one of claims 1-22, wherein, The pressure relief component is made of steel.

24. The battery cell according to claim 23, wherein, The steel is carbon steel or stainless steel.

25. A battery, comprising the battery cell according to any one of claims 1-24.

26. An electrical device, comprising the battery cell according to any one of claims 1-24.

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