Battery monomer, battery, energy storage device and power utilization device

Abstract

The invention provides a battery monomer, a battery, an energy storage device and a power utilization device, and belongs to the technical field of batteries. Wherein the battery monomer comprises a shell and a pressure relief part; the housing has a first wall having a first side facing the interior of the battery cell. The pressure relief part is arranged on the first wall, the pressure relief part is provided with a weak structure, the pressure relief part is configured to release the internal pressure of the battery monomer, and the weak structure does not exceed the first side face in the direction facing the interior of the battery monomer in the thickness direction of the first wall. According to the structure, the weak structure of the pressure relief piece can be well protected, so that the phenomenon of abrasion or damage caused by the fact that the weak structure of the pressure relief piece protrudes out of the first side surface can be relieved in the assembling process or the stacking storage process of the single batteries, and the service life of the pressure relief piece is prolonged; and in addition, the use reliability of the pressure relief piece is improved, normal use of the pressure relief piece is guaranteed, and then the risk that the valve is opened in advance of the pressure relief piece can be reduced.

Description

Battery cells, batteries, energy storage devices and power-consuming devices Technical Field

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

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing. Among them, batteries, as core components of new energy vehicles, have high requirements in terms of safety in use and service life. The battery cell of the battery is assembled into an electrode assembly (bare cell) by winding or laminating the positive electrode sheet, the negative electrode sheet and the diaphragm, which is then put into the outer shell and finally injected with electrolyte. A pressure relief part is usually provided on the outer shell of the battery cell to discharge the internal pressure of the battery cell when the battery cell has thermal runaway. However, the battery cells in the prior art have the problem of poor stability in use during use, which leads to low safety of the battery cell and a short service life.

[0003] Summary of the Invention

[0004] The embodiments of the present application provide a battery cell, a battery, an energy storage device, and an electrical device, which can effectively improve the service life and safety of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and a pressure relief member; the shell has a first wall, the first wall has a first side facing the interior of the battery cell, and the shell is used to accommodate an electrode assembly; the pressure relief member is arranged on the first wall; wherein, the pressure relief member has a weak structure, and along the thickness direction of the first wall, the weak structure does not exceed the first side in the direction facing the interior of the battery cell.

[0006] In the above technical solution, a pressure relief member is provided on the first wall of the housing, and the pressure relief member is provided with a weakened structure, so that the pressure relief member can release the internal pressure of the battery cell when an abnormal condition occurs in the battery cell, thereby reducing the risk of battery cell explosion. By setting the weakened structure of the pressure relief member so as not to extend beyond the first side surface of the first wall in the thickness direction, the weakened structure of the pressure relief member does not extend beyond the first side surface in the thickness direction of the first wall, thereby effectively protecting the location of the pressure relief member with the weakened structure. This can reduce the wear or damage caused by the weakened structure of the pressure relief member protruding from the first side surface during the production and assembly process of the battery cell or during the storage and transportation of multiple first walls stacked on each other. On the one hand, this can effectively extend the service life of the pressure relief member, which is beneficial to improving the service life of the battery cell equipped with such a pressure relief member. On the other hand, this can reduce the structural strength weakening of the weakened structure of the pressure relief member due to wear, which is beneficial to improving the reliability of the pressure relief member, ensuring the normal use of the pressure relief member, and further effectively reducing the risk of premature valve opening of the pressure relief member, thereby improving the safety of the battery cell equipped with such a pressure relief member.

[0007] In some embodiments, the weak structure is an area where the pressure relief member is provided with a notched groove; the notched groove is provided on the side of the pressure relief member facing away from the interior of the battery cell, and the pressure relief member is formed with a protrusion on the side facing the interior of the battery cell at a position corresponding to the notched groove, and the protrusion does not extend beyond the first side surface along the direction facing the interior of the battery cell.

[0008] In the above technical solution, a notched groove is provided on the side of the pressure relief member facing away from the interior of the battery cell, and a protrusion is formed on the other side of the pressure relief member corresponding to the notched groove, so that the area of ​​the pressure relief member where the notched groove is provided becomes a weak structure for relieving the internal pressure of the battery cell. This structure is simple and facilitates stable valve opening of the pressure relief member when an abnormality occurs in the battery cell. In addition, by configuring the protrusion on the side of the pressure relief member facing away from the notched groove so as not to extend beyond the first side surface of the first wall along the thickness direction of the first wall, the protrusion of the pressure relief member does not extend beyond the first side surface in the thickness direction of the first wall, thereby effectively protecting the area where the notched groove is provided on the pressure relief member, thereby alleviating the risk of wear or damage to the protrusion of the pressure relief member during the production and assembly of the battery cell.

[0009] In some embodiments, along the thickness direction of the first wall, the distance between the protrusion and the first side surface is H, satisfying H>0 mm.

[0010] In the above technical solution, by setting the distance between the protrusion in the thickness direction of the first wall and the first side surface to be greater than 0, that is, there is a gap between the protrusion in the thickness direction of the first wall and the first side surface, the battery cell adopting this structure can further alleviate the phenomenon of wear or damage of the protrusion during the production and assembly process of the battery cell, which is conducive to ensuring the reliability and stability of the pressure relief piece.

[0011] In some embodiments, the pressure relief member has a first surface facing the interior of the battery cell, a groove is provided on the first surface, and at least a portion of the protrusion is accommodated in the groove.

[0012] In the above technical solution, a groove is provided on the first surface of the pressure relief member facing the interior of the battery cell, so that at least a portion of the protrusion can be accommodated in the groove, thereby further providing better protection for the protrusion, thereby alleviating the wear or damage of the protrusion of the pressure relief member during manufacturing or assembly of the pressure relief member and the first wall, thereby helping to improve the service life and stability of the pressure relief member.

[0013] In some embodiments, along the thickness direction of the first wall, the protrusion does not extend beyond the first surface.

[0014] In the above technical solution, by ensuring that the protrusion does not extend beyond the first surface in the thickness direction of the first wall, that is, the protrusion is entirely accommodated in the groove provided on the first surface, the pressure relief piece with such a structure is beneficial to further enhance the protection effect of the protrusion so as to reduce the risk of the protrusion being worn or damaged. On the other hand, it can reduce the interference between the pressure relief pieces during the storage or transportation of multiple pressure relief pieces stacked on each other, thereby facilitating the stacking of the pressure relief pieces and saving floor space.

[0015] In some embodiments, the first surface is coplanar with the first side surface; or, along the thickness direction of the first wall, the first surface is farther away from the interior of the battery cell than the first side surface.

[0016] In the above technical solution, by setting the first surface of the pressure relief member to be coplanar with the first side surface or farther away from the interior of the battery cell than the first side surface, it is possible to ensure that the protrusion accommodated in the groove of the pressure relief member does not exceed the first side surface in the thickness direction of the first wall. The structure is simple and easy to manufacture and assemble.

[0017] In some embodiments, the pressure relief member includes a pressure relief portion and a mounting portion; the pressure relief portion is provided with the notch groove, and the pressure relief portion is formed with the protrusion at a position corresponding to the notch groove on the side facing the interior of the battery cell; the mounting portion is connected to the first wall, and the mounting portion is arranged around the pressure relief portion; wherein the thickness of the mounting portion is greater than the thickness of the pressure relief portion, and the mounting portion and the pressure relief portion enclose to form the groove.

[0018] In the above technical solution, the pressure relief member is composed of a pressure relief portion and a mounting portion surrounding the outside of the pressure relief portion, and the thickness of the mounting portion is set to be greater than the thickness of the pressure relief portion. This structure facilitates the connection of the pressure relief member to the first wall through the mounting portion to enhance the connection strength between the pressure relief member and the first wall. On the other hand, the mounting portion and the pressure relief portion enclose a groove to accommodate the protrusion. This structure is simple and facilitates the protection of the protrusion.

[0019] In some embodiments, the thickness of the mounting portion is L1, satisfying 0.1 mm ≤ L1 ≤ 0.4 mm.

[0020] In the above technical solution, by setting the thickness of the mounting portion of the pressure relief component to 0.1 mm to 0.4 mm, on the one hand, the phenomenon of insufficient connection strength between the mounting portion and the first wall due to the mounting portion being too thin can be alleviated, and on the other hand, the phenomenon of the mounting portion occupying too much space due to the mounting portion being too thick can be alleviated.

[0021] In some embodiments, the minimum thickness of the pressure relief portion where the notch groove is provided is L2, satisfying 0.03 mm ≤ L2 ≤ 0.15 mm.

[0022] In the above technical solution, by setting the minimum thickness of the position where the pressure relief part is provided with the notched groove to 0.03mm to 0.15mm, that is, the residual thickness of the position where the pressure relief part is provided with the notched groove is 0.03mm to 0.15mm, the pressure relief part with such a structure can, on the one hand, alleviate the phenomenon that the pressure relief part is easily damaged due to the minimum thickness of the position where the pressure relief part is provided with the notched groove being too small, and on the other hand, alleviate the phenomenon that the valve opening pressure required for the pressure relief part is too large due to the minimum thickness of the position where the pressure relief part is provided with the notched groove being too large, thereby helping to reduce the risk of using battery cells.

[0023] In some embodiments, the scored groove is an annular groove, and along the thickness direction of the first wall, the area of ​​the pressure relief portion located inside the scored groove is arched away from the interior of the battery cell.

[0024] In the above technical solution, by setting the notched groove as an annular structure and setting the area of ​​the pressure relief part located inside the notched groove as an arched shape, the pressure relief part with this structure facilitates setting the notched groove on the pressure relief part, thereby reducing the difficulty of processing the notched groove.

[0025] In some embodiments, the pressure relief member is a circular structure.

[0026] In the above technical solution, the pressure relief component is provided as a circular structure to facilitate assembly of the pressure relief component to the first wall, thereby reducing the difficulty of assembly and processing.

[0027] In some embodiments, the pressure relief member and the first wall are separate structures, a pressure relief hole is provided on the first wall, and the pressure relief member covers the pressure relief hole.

[0028] In the above technical solution, by providing the pressure relief member and the first wall as a separate structure and providing a pressure relief hole on the first wall, the pressure relief member can relieve the internal pressure of the battery cell by covering the pressure relief hole with the pressure relief member. This structure facilitates the installation and installation of the pressure relief member on the first wall, helps reduce assembly difficulty, and facilitates the subsequent maintenance and replacement of the pressure relief member. In some embodiments, the first side surface is provided with a receiving groove, the pressure relief hole extends through the bottom surface of the receiving groove, and the receiving groove is used to accommodate at least a portion of the pressure relief member.

[0029] In the above technical solution, a receiving groove is provided on the first side surface of the first wall so that the pressure relief member can be accommodated in the receiving groove. Thus, this structure is used to ensure that the protrusion of the pressure relief member does not exceed the first side surface of the first wall in the thickness direction of the first wall. The structure is simple and easy to implement.

[0030] In some embodiments, the accommodating groove includes a first groove and a second groove, the second groove is arranged on the bottom surface of the first groove, and the pressure relief hole passes through the bottom surface of the second groove; wherein, the pressure relief member is installed in the second groove and abuts against the bottom surface of the second groove, and the protrusion is accommodated in the first groove.

[0031] In the above technical solution, the accommodating groove includes a first groove and a second groove arranged in sequence along the thickness direction of the first wall, the second groove is arranged on the groove bottom surface of the first groove, and the pressure relief hole passes through the groove bottom surface of the second groove, that is, in the thickness direction of the first wall, the second groove is arranged between the first groove and the pressure relief hole, so that the pressure relief part is installed in the second groove and the protrusion of the pressure relief part is accommodated in the first groove, so that the protrusion does not exceed the first side surface of the first wall in the thickness direction of the first wall. This structure is simple and easy to assemble.

[0032] In some embodiments, along the thickness direction of the first wall, the first wall has a second side surface arranged opposite to the first side surface, and the second side surface is provided with a accommodating groove, the pressure relief hole passes through the bottom surface of the accommodating groove, and the accommodating groove is used to accommodate at least part of the pressure relief component.

[0033] In the above technical solution, an accommodating groove is provided on the second side surface of the first wall away from the first side surface, so that the pressure relief member can be accommodated in the accommodating groove, so that the pressure relief member is installed on the side of the first wall away from the interior of the battery cell. This structure ensures that the protrusion of the pressure relief member does not exceed the first side surface of the first wall in the thickness direction of the first wall. The structure is simple and easy to implement.

[0034] In some embodiments, the accommodating groove includes a third groove and a fourth groove, the fourth groove is arranged on the bottom surface of the third groove, and the pressure relief hole passes through the bottom surface of the fourth groove; wherein, the pressure relief part is installed in the fourth groove and abuts against the bottom surface of the fourth groove, and the protrusion is accommodated in the pressure relief hole.

[0035] In the above technical solution, the accommodating groove includes a third groove and a fourth groove sequentially arranged along the thickness direction of the first wall, the fourth groove is arranged on the groove bottom surface of the third groove, and the pressure relief hole passes through the groove bottom surface of the fourth groove, that is, in the thickness direction of the first wall, the fourth groove is arranged between the third groove and the pressure relief hole, so that the pressure relief component is installed in the fourth groove and the protrusion of the pressure relief component is accommodated in the pressure relief hole, so that the protrusion does not exceed the first side surface of the first wall in the thickness direction of the first wall. This structure is simple and easy to assemble.

[0036] In some embodiments, the weak structure is an area where the thickness of the pressure relief member is reduced; in the thickness direction of the first wall, the area where the thickness of the pressure relief member is reduced is close to the surface inside the battery cell and does not exceed the first side surface along the direction facing the inside of the battery cell.

[0037] In the above technical solution, by reducing the thickness of a portion of the pressure relief member, the reduced thickness region of the pressure relief member serves as a weak structure for relieving the internal pressure of the battery cell. This results in a simple structure and low processing difficulty. Furthermore, by positioning the reduced thickness region of the pressure relief member near the surface of the interior of the battery cell so that it does not extend beyond the first side surface of the first wall in the thickness direction of the first wall, the reduced thickness region of the pressure relief member does not extend beyond the first side surface in the thickness direction of the first wall. This effectively protects the reduced thickness region of the pressure relief member, thereby alleviating wear or damage to the reduced thickness region of the pressure relief member during the production and assembly of the battery cell.

[0038] In some embodiments, the battery cell further includes a protective member; the protective member is disposed on a side of the first wall facing away from the interior of the battery cell, and the protective member covers the pressure relief hole, and is used to protect the pressure relief member.

[0039] In the above technical solution, the battery cell is also provided with a protective part for protecting the pressure relief part. The protective part is arranged on the side of the first wall away from the interior of the battery cell, so as to provide better protection for the pressure relief part, thereby alleviating the risk of the pressure relief part being worn or damaged by other components during later use, thereby ensuring the stability and reliability of the use of the pressure relief part.

[0040] In some embodiments, along the thickness direction of the first wall, the first wall has a second side surface arranged opposite to the first side surface, and a mounting groove is provided on the second side surface, and at least a portion of the protective member is accommodated in the mounting groove.

[0041] In the above technical solution, an installation groove for accommodating the protective part is provided on the second side surface of the first wall so that the protective part can be accommodated in the installation groove, thereby providing better protection for the protective part, thereby alleviating the phenomenon of damage to the protective part caused by the influence of the external environment during later use, and thus helping to extend the service life of the protective part.

[0042] In some embodiments, along the thickness direction of the first wall, the protection member does not extend beyond the second side surface.

[0043] In the above technical solution, by setting the protective member in the thickness direction of the first wall so as not to exceed the second side surface of the first wall, that is, the protective member is entirely accommodated in the installation groove, the battery cell adopting this structure can enhance the protection effect of the protective member, thereby reducing the risk of damage to the protective member during use.

[0044] In some embodiments, the housing includes a shell and an end cover assembly; the shell has an opening; the end cover assembly has an end cover, and the end cover covers the opening; wherein the first wall is the end cover.

[0045] In the above technical solution, the first wall is the end cover, that is, the pressure relief member is arranged on the end cover of the end cover assembly. The battery cell adopting this structure facilitates the pressure relief member to be arranged on the shell, which is conducive to reducing the difficulty of setting the pressure relief member on the shell.

[0046] In some embodiments, the end cap assembly further includes an electrode terminal, a connector and a first insulating member; the electrode terminal is insulated and mounted on the end cap; the connector is disposed on a side of the end cap facing away from the interior of the battery cell, and the connector is connected to the electrode terminal; the first insulating member is disposed between the connector and the end cap to insulate and isolate the connector and the end cap.

[0047] In the above technical solution, the end cap is insulated with an electrode terminal, which is connected to a connector provided on the side of the end cap facing away from the interior of the battery cell. This secures the electrode terminal to the end cap and facilitates assembly, thereby enabling the input or output of electrical energy to the battery cell via the electrode terminal provided on the end cap. Furthermore, a first insulating member is provided between the connector and the end cap, providing insulation and isolation between the connector and the end cap, thereby reducing the risk of short circuits in the battery cell.

[0048] In some embodiments, the end cap assembly further includes a current collecting member and a second insulating member; the current collecting member is arranged on the side of the end cap facing the interior of the battery cell, and the current collecting member connects the electrode terminal and the electrode assembly; the second insulating member is arranged between the current collecting member and the end cap to insulate and isolate the current collecting member and the end cap.

[0049] In this technical solution, a current collecting member is provided on the side of the end cap facing away from the connector. This current collecting member connects the electrode terminal to the electrode assembly, thereby achieving electrical connection between the electrode assembly and the electrode terminal. This structure is simple and easy to assemble. Furthermore, a second insulating member is provided between the current collecting member and the end cap, providing insulation and isolation between the two, thereby reducing the risk of short circuits in the battery cells.

[0050] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0051] In a third aspect, an embodiment of the present application further provides an energy storage device comprising the above-mentioned battery.

[0052] In a fourth aspect, an embodiment of the present application further provides an electrical device comprising the above-mentioned battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0055] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0056] FIG3 is an exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0057] FIG4 is a schematic structural diagram of an end cap assembly provided in some embodiments of the present application;

[0058] FIG5 is an exploded view of the structure of an end cap assembly provided in some embodiments of the present application;

[0059] FIG6 is a cross-sectional view of a pressure relief member connected to a first wall according to some embodiments of the present application;

[0060] FIG7 is a partial enlarged view of the pressure relief member shown in FIG6 connected to the first wall at A;

[0061] FIG8 is a partial cross-sectional view of a pressure relief member connected to a first wall according to some other embodiments of the present application;

[0062] FIG9 is a schematic structural diagram of a plurality of first walls stacked on each other after a pressure relief member is connected to the first wall according to some embodiments of the present application;

[0063] FIG10 is a schematic structural diagram of a pressure relief member provided in some embodiments of the present application;

[0064] FIG11 is a cross-sectional view of a pressure relief member provided in some embodiments of the present application;

[0065] FIG12 is a cross-sectional view of a pressure relief member connected to a first wall according to some other embodiments of the present application;

[0066] FIG13 is a partial enlarged view of the pressure relief member shown in FIG12 connected to the first wall at B;

[0067] FIG14 is a cross-sectional view of a pressure relief member connected to a first wall according to yet other embodiments of the present application;

[0068] FIG15 is a partial enlarged view of the pressure relief member shown in FIG14 connected to the first wall at C;

[0069] FIG16 is a cross-sectional view of a pressure relief member connected to a first wall according to other embodiments of the present application;

[0070] FIG17 is a partial enlarged view of the pressure relief member shown in FIG16 connected to the first wall at D. FIG.

[0071] Icon: 1000-vehicle; 100-battery; 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-opening; 22-electrode assembly; 221-ear; 23-end cap assembly; 231-end cap; 231a-first wall; 2311-first side; 2312-pressure relief hole; 2313-accommodation groove; 2313a-first groove; 2313b-second groove; 2313c-third groove; 2313d-fourth groove; 2314-second side; 2 315-mounting groove; 2316-lead-out hole; 232-pressure relief member; 2321-notched groove; 2322-protrusion; 2323-first surface; 2324-groove; 2325-mounting portion; 2326-pressure relief portion; 233-mounting member; 234-protective member; 235-electrode terminal; 236-connecting member; 237-first insulating member; 238-sealing member; 239-current collecting member; 240-second insulating member; 200-controller; 300-motor; X-thickness direction of the first wall; Y-first direction. DETAILED DESCRIPTION

[0072] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0073] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0074] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0075] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0076] 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.

[0077] 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.

[0078] The term "plurality" used in this application refers to two or more (including two).

[0079] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0080] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a housing that encloses one or more battery cells or multiple battery modules. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0081] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The portion of the positive electrode collector not coated with the positive active material layer serves as the positive tab, allowing power to be input or output from the positive electrode sheet. For lithium-ion batteries, for example, the positive electrode current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The portion of the negative electrode collector not coated with the negative active material layer serves as the negative tab, allowing power to be input or output from the negative electrode sheet. The negative electrode current collector can be made of copper, and the negative active material can be carbon or silicon, among others. In order to ensure that large currents can pass without melting, there are multiple positive electrode tabs and they are stacked together, and there are multiple negative electrode tabs and they are stacked together.

[0082] The material of the isolation film may be polypropylene (PP) or polyethylene (PE), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the present invention is not limited thereto.

[0083] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, and are an important component of today's new energy development. A battery cell is an electrode assembly (bare cell) composed of a positive electrode sheet, a negative electrode sheet, and a separator film, which are assembled through winding or lamination, then enclosed in a casing and finally injected with electrolyte. However, with the continuous development of battery technology, higher requirements have been placed on battery safety performance and service life. Among them, the safety and service life of the battery cell directly determine the safety performance and service life of the battery.

[0084] For general battery cells, when a short circuit or overcharge occurs in a battery cell, the battery cell is very likely to cause a sudden increase in internal air pressure due to internal thermal runaway, thereby leading to safety hazards such as battery fire and explosion. Therefore, an explosion-proof valve is usually provided on the outer shell of the battery cell so that the internal air pressure of the battery cell can break through the explosion-proof valve when thermal runaway occurs in the battery cell, so that the internal air pressure of the battery cell can be released, thereby reducing the risk of fire and explosion of the battery cell.

[0085] The inventors discovered that existing explosion-proof valves are typically provided with notched grooves to weaken the valve structure, allowing the notched groove area to rupture under the impact of internal air pressure generated by thermal runaway of the battery cell, thereby better ensuring the release of internal air pressure in the battery cell and improving the safety of the battery cell. However, the notched grooves on the explosion-proof valve are typically formed using a stamping process, resulting in a raised structure on the other side of the explosion-proof valve corresponding to the notched groove. This type of explosion-proof valve often suffers from wear or damage to the raised structure during the production and assembly of the battery cell. This significantly reduces the service life of the explosion-proof valve, hindering the service life of the battery cell. Furthermore, it weakens the structural strength of the explosion-proof valve at the location where the notched groove is provided, which can easily reduce the stability and reliability of the explosion-proof valve. This makes it impossible to ensure the normal operation of the explosion-proof valve and increases the risk of premature valve opening, which is detrimental to the safety of the battery cell.

[0086] Based on the above considerations, in order to solve the problems of short service life and poor safety of battery cells, the inventors, after in-depth research, designed a battery cell, which includes a housing and a pressure relief member. The housing has a first wall, the first wall having a first side facing the interior of the battery cell, and the housing is used to accommodate the electrode assembly. The pressure relief member is provided on the first wall and is configured to release the internal pressure of the battery cell. The pressure relief member has a weak structure, and along the thickness direction of the first wall, the weak structure does not extend beyond the first side in the direction facing the interior of the battery cell.

[0087] In a battery cell of this structure, a pressure relief member is provided on the first wall of the housing, and the pressure relief member is provided with a weakened structure, so that the pressure relief member can release internal pressure in the battery cell when an abnormal condition occurs in the battery cell, thereby reducing the risk of battery cell explosion. By disposing the weakened structure of the pressure relief member so as not to extend beyond the first side surface of the first wall in the thickness direction of the first wall, the weakened structure of the pressure relief member does not extend beyond the first side surface in the thickness direction of the first wall, thereby effectively protecting the location of the pressure relief member where the weakened structure is located. This reduces the risk of wear or damage to the pressure relief member caused by the weakened structure protruding from the first side surface during the production and assembly of the battery cell or during storage and transportation of multiple first walls stacked on each other. This effectively extends the service life of the pressure relief member, thereby improving the service life of the battery cell having such a pressure relief member. It also reduces the risk of weakening of the structural strength of the weakened structure of the pressure relief member due to wear, thereby improving the reliability of the pressure relief member, ensuring normal operation of the pressure relief member, and effectively reducing the risk of premature valve opening of the pressure relief member, thereby improving the safety of the battery cell having such a pressure relief member.

[0088] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices 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 devices. This helps improve the operational stability and reliability of the pressure relief member, ensuring its proper operation and effectively extending the service life and safety of the battery cells.

[0089] The present invention provides 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.

[0090] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0091] Please refer to Figure 1, which is a schematic structural 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, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating 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.

[0092] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0093] Please refer to Figure 2, which is an exploded view of the structure of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, which is used to be accommodated in the housing 10. The housing 10 is used to provide an assembly space for the battery cell 20, and the housing 10 can adopt various structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12, which cover each other and together define an assembly space for accommodating the battery cell 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, with the first housing body 11 covering the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define an assembly space; the first housing body 11 and the second housing body 12 can also be hollow structures with one end open, with the open side of the first housing body 11 covering the open side of the second housing body 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0094] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0095] 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 cylindrical, flat, rectangular, or in other shapes. For example, in FIG2 , the battery cell 20 is cylindrical.

[0096] Please refer to Figures 3 and 4. Figure 3 is an exploded view of the structure of a battery cell 20 provided in some embodiments of the present application, and Figure 4 is a schematic diagram of the structure of an end cap assembly 23 provided in some embodiments of the present application. The battery cell 20 includes a housing 21, an electrode assembly 22, and an end cap assembly 23. The housing 21 has an opening 211, and the electrode assembly 22 is accommodated within the housing 21. The end cap assembly 23 covers the opening 211 and is electrically connected to the electrode assembly 22 to enable the input or output of electrical energy from the battery cell 20.

[0097] The housing 21 and the end cap assembly 23 together form a shell for accommodating the electrode assembly 22. That is, the shell of the battery cell 20 is composed of the housing 21 and the end cap assembly 23. The end cap assembly 23 includes an end cap 231, which covers the opening 211 of the housing 21.

[0098] The housing 21 can also be used to contain electrolytes, such as electrolytes. The housing 21 can have various structural forms. The housing 21 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloys, etc.

[0099] For example, in FIG3 , the housing 21 is a hollow structure with two opposing openings 211. The battery cell 20 includes two end cap assemblies 23. One end cap assembly 23 is fitted over one opening 211 of the housing 21 and forms a sealed connection, thereby creating a sealed space for accommodating the electrode assembly 22 and the electrolyte. When assembling the battery cell 20, the electrode assembly 22 can be placed into the housing 21 first. Then, one end cap assembly 23 is fitted over one opening 211 of the housing 21, and the housing 21 is filled with electrolyte. Finally, the other end cap assembly 23 is fitted over the other opening 211 of the housing 21 to complete the assembly of the battery cell 20.

[0100] It is understandable that the battery cell 20 is not limited to the above structure. The battery cell 20 can also have other structures. For example, the shell 21 is a hollow structure with an opening 211 on one side, and the end cover assembly 23 covers the opening 211 of the shell 21 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

[0101] The shell 21 can also be in various shapes, such as a cylinder, a cuboid, etc. The shape of the shell 21 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a shell 21 with a cylindrical structure can be selected; if the electrode assembly 22 is a cuboid structure, a shell 21 with a cuboid structure can be selected. Of course, the end cap assembly 23 can also be in various structures. The shape of the end cap assembly 23 can be adapted to the shape of the shell 21, for example, the end cap assembly 23 is a plate-like structure, a hollow structure with an opening 211 at one end, etc. For example, in Figure 3, the electrode assembly 22 is a cylindrical structure, and the shell 21 is a cylindrical structure, and the end cap assembly 23 covers the opening 211 of the shell 21.

[0102] The end cap assembly 23 is a component that covers the opening 211 of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment.

[0103] It should be noted that the electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction occurs. The electrode assembly 22 may include a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly 22 may be a wound structure formed by winding the positive electrode sheet, the separator, and the negative electrode sheet, or a stacked structure formed by stacking the positive electrode sheet, the separator, and the negative electrode sheet. For example, in Figure 3, the electrode assembly 22 is a wound structure formed by winding the positive electrode sheet, the separator, and the negative electrode sheet.

[0104] As shown in FIG3 , electrode assembly 22 is formed with tabs 221 at both ends, i.e., tabs 221 are formed at both ends of electrode assembly 22 facing end cap assembly 23. Tabs 221 are used to electrically connect to end cap assembly 23, thereby achieving electrical connection between electrode assembly 22 and end cap assembly 23, thereby enabling the input or output of electrical energy from battery cell 20. The two tabs 221 are used to output the positive and negative electrodes of electrode assembly 22, respectively. Correspondingly, the two end cap assemblies 23 also serve as the positive and negative output electrodes of battery cell 20, respectively. It should be noted that the tabs 221 of electrode assembly 22 can be directly connected to end cap assembly 23, for example, by welding or abutting the tabs 221. Alternatively, the tabs 221 of electrode assembly 22 can be indirectly connected to end cap assembly 23, for example, by welding or abutting the tabs 221 to other components before being connected to end cap assembly 23.

[0105] Optionally, there may be one or more electrode assemblies 22 housed in the housing 21. For example, in FIG3 , there is only one electrode assembly 22.

[0106] According to some embodiments of the present application, referring to Figures 3 and 4, and further referring to Figures 5, 6, and 7, Figure 5 is an exploded view of the structure of the end cap assembly 23 provided in some embodiments of the present application, Figure 6 is a cross-sectional view of a pressure relief member 232 connected to a first wall 231a provided in some embodiments of the present application, and Figure 7 is a partial enlarged view of the pressure relief member 232 connected to the first wall 231a shown in Figure 6 at point A. The present application provides a battery cell 20, comprising a housing and a pressure relief member 232. The housing has a first wall 231a, the first wall 231a having a first side surface 2311 facing the interior of the battery cell 20, and the housing is used to accommodate the electrode assembly 22. The pressure relief member 232 is disposed on the first wall 231a. The pressure relief member 232 has a weak structure, and along the thickness direction X of the first wall, the weak structure does not extend beyond the first side surface 2311 in the direction facing the interior of the battery cell 20.

[0107] In the thickness direction X of the first wall, the direction of the weak structure facing the interior of the battery cell 20 is the first direction Y shown in Figures 6 and 7. The first direction Y is parallel to the thickness direction X of the first wall and is unidirectional.

[0108] In Figure 3, the housing is composed of a shell 21 and an end cap assembly 23. The end cap 231 of the end cap assembly 23 covers the opening 211 of the shell 21, thereby forming a sealed space between the end cap 231 and the shell 21 for accommodating the electrode assembly 22 and the electrolyte. The end cap 231 can be made of a variety of materials, such as copper, iron, aluminum, steel, and aluminum alloys.

[0109] For example, in FIG. 6 and FIG. 7 , the first wall 231 a is the end cover 231 . Of course, in other embodiments, the first wall 231 a may also be the housing 21 .

[0110] Optionally, the pressure relief member 232 can be an integrally formed structure with the first wall 231a, or the pressure relief member 232 and the first wall 231a can be a split structure, with the pressure relief member 232 connected to the first wall 231a. For example, in Figures 6 and 7, the pressure relief member 232 and the first wall 231a are split structures, and the first wall 231a is provided with a pressure relief hole 2312, and the pressure relief member 232 covers the pressure relief hole 2312. The pressure relief member 232 and the first wall 231a can be connected in various ways, such as bonding, welding, or clamping. In some embodiments, referring to Figure 8, Figure 8 is a partial cross-sectional view of the pressure relief member 232 connected to the first wall 231a provided in some other embodiments of the present application. The pressure relief member 232 and the first wall 231a are an integral structure, that is, the first wall 231a is formed with a region having a weak structure by a process such as stamping or casting, and this region is the pressure relief member 232.

[0111] The pressure relief member 232 serves to release the internal pressure of the battery cell 20 in the event of thermal runaway. Specifically, the pressure relief member 232 can rupture along a weak structure in the event of thermal runaway, thereby releasing the internal pressure of the battery cell 20. The pressure relief member 232 can have various structures. For example, if the pressure relief member 232 and the first wall 231a are integrally formed, the pressure relief member 232 is a weak area formed on the first wall 231a. If the pressure relief member 232 and the first wall 231a are separate structures, the pressure relief member 232 can be a component such as an explosion-proof valve, explosion-proof disk, air valve, pressure relief valve, or safety valve.

[0112] The weakened structure on the pressure relief member 232 is configured to rupture when the battery cell 20 experiences thermal runaway, thereby releasing the internal pressure of the battery cell 20. The weakened structure of the pressure relief member 232 can be of various types, such as a notched area on the pressure relief member 232 or a thinned area on the pressure relief member 232.

[0113] For example, in FIG7 , a region with reduced thickness is formed on the pressure relief member 232, and a notch 2321 is provided in the region with reduced thickness, so that the pressure relief member 232 forms a relatively weak region at the location where the notch 2321 is provided. That is, the region where the notch 2321 is provided on the pressure relief member 232 constitutes a weak structure of the pressure relief member 232, so that the pressure relief member 232 is configured to rupture along the notch 2321 when the internal pressure or temperature of the battery cell 20 reaches a threshold value, thereby being able to release the internal pressure of the battery cell 20. Of course, in other embodiments, it is also possible to suffice to provide only the region with reduced thickness or only the notch 2321 on the pressure relief member 232.

[0114] The pressure relief hole 2312 on the first wall 231a is a channel for discharging emissions generated inside the battery cell 20 when thermal runaway occurs in the battery cell 20. When the pressure relief member 232 releases the internal pressure of the battery cell 20, the pressure relief hole 2312 can be connected to both the interior and external environment of the battery cell 20, so that the emissions generated inside the battery cell 20 can be discharged through the pressure relief hole 2312.

[0115] The first side surface 2311 of the first wall 231a is the surface of the first wall 231a facing the interior of the battery cell 20. For example, in Figures 5 and 6, the first wall 231a is the end cover 231, that is, the first side surface 2311 is the lower surface of the end cover 231 facing the electrode assembly 22 in the first direction Y.

[0116] Along the thickness direction X of the first wall, the weak structure does not extend beyond the first side surface 2311 in the direction facing the interior of the battery cell 20. That is, the pressure relief member 232 is mounted on the first wall 231a. In the thickness direction X of the first wall and in the direction from the first side surface 2311 toward the interior of the battery cell 20, that is, in the first direction Y, the region of the pressure relief member 232 having the weak structure does not extend beyond the first side surface 2311. For example, in FIG. 7 , the weak structure is the region of the pressure relief member 232 where the notched groove 2321 is provided. That is, the region of the pressure relief member 232 where the notched groove 2321 is provided does not extend beyond the first side surface 2311 in the first direction Y.

[0117] It should be noted that the pressure relief member 232 can be installed on the first wall 231a in various structures. For example, in Figure 7, a receiving groove 2313 is provided on the first side surface 2311 of the first wall 231a, and the pressure relief hole 2312 is connected to the interior of the battery cell 20 through the receiving groove 2313. The pressure relief member 232 is accommodated in the receiving groove 2313 and covers the pressure relief hole 2312, so that the weak structure of the pressure relief member 232 does not exceed the first side surface 2311 in the first direction Y. Of course, in other embodiments, the first wall 231a can also be other structures. For example, it can be a recessed area formed in the edge area of ​​the first side surface 2311 of the first wall 231a, the pressure relief hole 2312 passes through the surface of the recessed area, and the pressure relief member 232 is installed in the recessed area of ​​the first side surface 2311 so that the weak structure of the pressure relief member 232 does not exceed the first side surface 2311 in the first direction Y; it can also be that the pressure relief member 232 is assembled in the pressure relief hole 2312 and the pressure relief hole 2312 is blocked, and the pressure relief hole 2312 passes through the first side surface 2311 of the first wall 231a so that the weak structure of the pressure relief member 232 does not exceed the first side surface 2311 in the first direction Y.

[0118] A pressure relief member 232 is provided on the first wall 231a, and the pressure relief member 232 is provided with a weak structure, so that the pressure relief member 232 can release the internal pressure of the battery cell 20 when an abnormal situation occurs in the battery cell 20, thereby reducing the risk of explosion of the battery cell 20. By setting the weak structure of the pressure relief member 232 so as not to exceed the first side surface 2311 of the first wall 231a in the thickness direction X of the first wall, the weak structure of the pressure relief member 232 does not extend beyond the first side surface 2311 in the thickness direction X of the first wall, thereby providing better protection for the position where the pressure relief member 232 has the weak structure, so that during the production and assembly process of the battery cell 20 or when multiple first walls 231a are stacked on each other for storage and transportation (refer to Figure 9, Figure 9 shows the structure of multiple first walls 231a stacked on each other after the pressure relief member 232 is connected to the first wall 231a according to some embodiments of the present application). Schematic diagram of the structure. ) It can alleviate the phenomenon of wear or damage caused by the weak structure of the pressure relief member 232 protruding from the first side surface 2311. On the one hand, it can effectively extend the service life of the pressure relief member 232, which is beneficial to improving the service life of the battery cell 20 with such a pressure relief member 232. On the other hand, it can alleviate the phenomenon of structural strength weakening due to wear of the weak structure of the pressure relief member 232, which is beneficial to improving the reliability of the pressure relief member 232, so as to ensure the normal use of the pressure relief member 232, and further effectively reduce the risk of premature valve opening of the pressure relief member 232, so as to improve the safety of the battery cell 20 with such a pressure relief member 232.

[0119] In some embodiments, as shown in Figures 6 and 7 , the weak structure is an area of ​​the pressure relief member 232 provided with a notched groove 2321. The notched groove 2321 is provided on the side of the pressure relief member 232 facing away from the interior of the battery cell 20, and a protrusion 2322 is formed on the side of the pressure relief member 232 facing the interior of the battery cell 20 at a position corresponding to the notched groove 2321. The protrusion 2322 does not extend beyond the first side surface 2311 along the direction facing the interior of the battery cell 20 (i.e., the first direction Y).

[0120] In which, the protrusion 2322 does not exceed the first side surface 2311 along the direction facing the interior of the battery cell 20, that is, the protrusion 2322 does not exceed the first side surface 2311 in the direction from the first side surface 2311 to the interior of the battery cell 20 along the thickness direction X of the first wall. In other words, the protrusion 2322 does not exceed the first side surface 2311 in the first direction Y, so that the protrusion 2322 is located as a whole in the accommodating groove 2313 set on the first wall 231a.

[0121] By providing a notched groove 2321 on the side of the pressure relief member 232 facing away from the interior of the battery cell 20 and forming a protrusion 2322 on the other side of the pressure relief member 232 corresponding to the notched groove 2321, the area of ​​the pressure relief member 232 where the notched groove 2321 is provided becomes a weak structure for relieving the internal pressure of the battery cell 20. This simple structure facilitates stable opening of the pressure relief member 232 in the event of an abnormality in the battery cell 20. Furthermore, by configuring the protrusion 2322 on the side of the pressure relief member 232 facing away from the notched groove 2321 so as not to extend beyond the first side surface 2311 of the end cap 231 in the first direction Y, the protrusion 2322 of the pressure relief member 232 does not extend beyond the first side surface 2311 in the thickness direction X of the first wall. This effectively protects the area of ​​the pressure relief member 232 where the notched groove 2321 is provided, thereby mitigating wear or damage to the protrusion 2322 of the pressure relief member 232 during the production and assembly of the battery cell 20.

[0122] According to some embodiments of the present application, as shown in FIG. 7 , along the thickness direction X of the first wall, the distance between the protrusion 2322 and the first side surface 2311 is H, satisfying H>0 mm.

[0123] Wherein, H>0mm, that is, there is a gap between the protrusion 2322 and the first side surface 2311 in the thickness direction X of the first wall. For example, the distance between the protrusion 2322 and the first side surface 2311 in the thickness direction X of the first wall can be 0.01mm, 0.02mm, 0.05mm, 0.08mm, 0.1mm, 0.11mm, or 0.12mm.

[0124] By setting the distance between the protrusion 2322 and the first side surface 2311 in the thickness direction X of the first wall to be greater than 0, the battery cell 20 adopting this structure can further alleviate the phenomenon of wear or damage of the protrusion 2322 during the production and assembly process of the battery cell 20, which is conducive to ensuring the reliability and stability of the pressure relief member 232.

[0125] According to some embodiments of the present application, referring to Figures 6 and 7, and further referring to Figures 10 and 11, Figure 10 is a schematic structural diagram of a pressure relief member 232 provided in some embodiments of the present application, and Figure 11 is a cross-sectional view of a pressure relief member 232 provided in some embodiments of the present application. The pressure relief member 232 has a first surface 2323 facing the interior of the battery cell 20, and a groove 2324 is provided on the first surface 2323. At least a portion of the protrusion 2322 is accommodated in the groove 2324.

[0126] Among them, the pressure relief member 232 has a first surface 2323 facing the interior of the battery cell 20. The first surface 2323 is the surface closest to the interior of the battery cell 20 among the multiple surfaces of the pressure relief member 232 facing the interior of the battery cell 20 in the thickness direction X of the first wall. That is, the first surface 2323 is the surface of the pressure relief member 232 closest to the electrode assembly 22 in the first direction Y.

[0127] At least a portion of the protrusion 2322 is accommodated in the groove 2324. That is, the protrusion 2322 may be entirely located in the groove 2324 provided on the first surface 2323, or may be partially located in the groove 2324 provided on the first surface 2323. In other words, the protrusion 2322 may extend out of the groove 2324 in the thickness direction X of the first wall. For example, in FIG11 , the protrusion 2322 is entirely located in the groove 2324 provided on the first surface 2323.

[0128] By providing a groove 2324 on the first surface 2323 of the pressure relief member 232 facing the interior of the battery cell 20, at least a portion of the protrusion 2322 can be accommodated in the groove 2324, thereby further providing better protection for the protrusion 2322, thereby alleviating the wear or damage of the protrusion 2322 of the pressure relief member 232 during manufacturing or when the pressure relief member 232 and the first wall 231a are assembled with each other, thereby helping to improve the service life and stability of the pressure relief member 232.

[0129] According to some embodiments of the present application, as shown in FIG. 7 and FIG. 11 , along the thickness direction X of the first wall, the protrusion 2322 does not extend beyond the first surface 2323 .

[0130] The protrusion 2322 does not extend beyond the first surface 2323 , that is, the protrusion 2322 is entirely accommodated in the groove 2324 provided on the first surface 2323 . In other words, in the first direction Y, the protrusion 2322 does not extend beyond the first surface 2323 .

[0131] By ensuring that the protrusion 2322 does not extend beyond the first surface 2323 in the thickness direction X of the first wall, the pressure relief piece 232 with such a structure is beneficial for, on the one hand, further enhancing the protection effect of the protrusion 2322 to reduce the risk of the protrusion 2322 being worn or damaged; on the other hand, it is beneficial for reducing the interference between the pressure relief pieces 232 during the storage or transportation of multiple pressure relief pieces 232 stacked on each other, thereby facilitating the stacking of the pressure relief pieces 232 and saving floor space.

[0132] In some embodiments, the first surface 2323 is coplanar with the first side surface 2311 . Alternatively, along the thickness direction X of the first wall, the first surface 2323 is farther away from the interior of the battery cell 20 than the first side surface 2311 .

[0133] 7 , the first surface 2323 and the first side surface 2311 are coplanar, i.e., the first surface 2323 and the first side surface 2311 are flush with each other. Of course, in other embodiments, the first surface 2323 may also be arranged farther from the interior of the battery cell 20 than the first side surface 2311 in the thickness direction X of the first wall, i.e., the first surface 2323 is retracted into the receiving groove 2313 of the first wall 231a.

[0134] By setting the first surface 2323 of the pressure relief member 232 to be coplanar with the first side surface 2311 or further away from the interior of the battery cell 20 than the first side surface 2311, it is possible to ensure that the protrusion 2322 accommodated in the groove 2324 of the pressure relief member 232 does not exceed the first side surface 2311 in the thickness direction X of the first wall. The structure is simple and easy to manufacture and assemble.

[0135] According to some embodiments of the present application, as shown in Figures 10 and 11, the pressure relief member 232 includes a mounting portion 2325 and a pressure relief portion 2326. The pressure relief portion 2326 is provided with a notch 2321, and the pressure relief portion 2326 has a protrusion 2322 formed on the side facing the interior of the battery cell 20 at a position corresponding to the notch 2321. The mounting portion 2325 is connected to the first wall 231a and is arranged around the pressure relief portion 2326. The thickness of the mounting portion 2325 is greater than the thickness of the pressure relief portion 2326, and the mounting portion 2325 and the pressure relief portion 2326 enclose a groove 2324.

[0136] The mounting portion 2325 is disposed around the pressure relief portion 2326 , that is, the mounting portion 2325 is an annular structure and surrounds the outer side of the pressure relief portion 2326 .

[0137] The thickness of the mounting portion 2325 is greater than the thickness of the pressure relief portion 2326. The mounting portion 2325 and the pressure relief portion 2326 enclose a groove 2324, that is, the mounting portion 2325 and the pressure relief portion 2326 jointly define the groove 2324, and the mounting portion 2325 has a first surface 2323, that is, the surface of the mounting portion 2325 facing the interior of the battery cell 20 in the first direction Y is the first surface 2323.

[0138] The pressure relief member 232 is composed of a pressure relief portion 2326 and a mounting portion 2325 surrounding the outside of the pressure relief portion 2326, and the thickness of the mounting portion 2325 is set to be greater than the thickness of the pressure relief portion 2326. This structure facilitates the pressure relief member 232 to be connected to the first wall 231a through the mounting portion 2325 to enhance the connection strength between the pressure relief member 232 and the first wall 231a. On the other hand, the mounting portion 2325 and the pressure relief portion 2326 enclose a groove 2324 for accommodating the protrusion 2322. This structure is simple and facilitates protecting the protrusion 2322.

[0139] In some embodiments, as shown in FIG. 11 , the thickness of the mounting portion 2325 is L1 , satisfying 0.1 mm ≤ L1 ≤ 0.4 mm.

[0140] The mounting portion 2325 is a flat plate-shaped structure, and its thickness is L1, i.e., the maximum dimension of the mounting portion 2325 in the thickness direction X of the first wall is L1. If the mounting portion 2325 is an arc-shaped structure, the thickness of the mounting portion 2325 is the maximum dimension of the mounting portion 2325 in the direction of its curvature radius.

[0141] Optionally, the thickness L1 of the mounting portion 2325 may be 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, or 0.4 mm, etc.

[0142] By setting the thickness of the mounting portion 2325 of the pressure relief member 232 to 0.1 mm to 0.4 mm, on the one hand, the phenomenon of insufficient connection strength between the mounting portion 2325 and the first wall 231a due to the mounting portion 2325 being too thin can be alleviated; on the other hand, the phenomenon of the mounting portion 2325 occupying too much space due to the mounting portion 2325 being too thick can be alleviated.

[0143] In some embodiments, please continue to refer to FIG. 11 , the minimum thickness of the pressure relief portion 2326 at the location where the notch groove 2321 is provided is L2, satisfying 0.03 mm ≤ L2 ≤ 0.15 mm.

[0144] The minimum thickness of the pressure relief portion 2326 at the location where the notched groove 2321 is provided is L2, i.e., the dimension of the remaining portion of the pressure relief portion 2326 at the location where the notched groove 2321 is formed is L2. In FIG11 , since the pressure relief portion 2326 is an arc-shaped structure, the minimum thickness of the pressure relief portion 2326 at the location where the notched groove 2321 is provided is the minimum dimension of the pressure relief portion 2326 at the location where the notched groove 2321 is provided in the direction of the curvature radius of the pressure relief portion 2326.

[0145] Furthermore, 0.04mm≤L2≤0.1mm, that is, the minimum thickness L2 of the position where the pressure relief portion 2326 is provided with the notched groove 2321 is 0.04mm to 0.1mm. Exemplarily, the minimum thickness L2 of the position where the pressure relief portion 2326 is provided with the notched groove 2321 can be 0.04mm, 0.05mm, 0.06mm, 0.08mm or 0.1mm, etc.

[0146] By setting the minimum thickness of the position where the pressure relief part 2326 is provided with the notched groove 2321 to 0.03mm to 0.15mm, the pressure relief part 232 with such a structure can, on the one hand, alleviate the phenomenon that the pressure relief part 232 is easily damaged due to the minimum thickness of the position where the pressure relief part 2326 is provided with the notched groove 2321 being too small; on the other hand, it can alleviate the phenomenon that the valve opening pressure required for the pressure relief part 2326 is too large due to the minimum thickness of the position where the pressure relief part 2326 is provided with the notched groove 2321 being too large, thereby helping to reduce the use risk of the battery cell 20.

[0147] According to some embodiments of the present application, as shown in Figures 10 and 11, the notched groove 2321 is an annular groove. Along the thickness direction X of the first wall, the area inside the pressure relief portion 2326 located on the inside of the notched groove 2321 is arched away from the interior of the battery cell 20.

[0148] The notched groove 2321 may be an annular groove, that is, the notched groove 2321 is a structure connected end to end in its extending direction; of course, the notched groove 2321 may also be an open annular groove.

[0149] The area of ​​the pressure relief portion 2326 located inside the notched groove 2321 is arched in a direction away from the interior of the battery cell 20, that is, the area of ​​the pressure relief portion 2326 located inside the notched groove 2321 is arched toward the outside of the battery cell 20 in the thickness direction X of the first wall, that is, the area of ​​the pressure relief portion 2326 located inside the notched groove 2321 is arched in a direction away from the first direction Y.

[0150] By setting the notched groove 2321 as an annular structure and setting the area of ​​the pressure relief part 2326 located inside the notched groove 2321 as an arched shape, the pressure relief part 232 with this structure facilitates setting the notched groove 2321 on the pressure relief part 2326, thereby reducing the processing difficulty of the notched groove 2321.

[0151] In some embodiments, as shown in FIG10 , the pressure relief member 232 is a circular structure. Of course, in other embodiments, the pressure relief member 232 may also be a rectangular structure, an elliptical structure, or a triangular structure.

[0152] By providing the pressure relief member 232 with a circular structure, it is convenient to assemble the pressure relief member 232 onto the first wall 231 a , which helps to reduce the difficulty of assembly and processing.

[0153] According to some embodiments of the present application, as shown in FIG. 5 , the pressure relief member 232 and the first wall 231 a are split structures. A pressure relief hole 2312 is provided on the first wall 231 a , and the pressure relief member 232 covers the pressure relief hole 2312 .

[0154] The pressure relief member 232 and the first wall 231a are split structures, that is, the pressure relief member 232 and the first wall 231a are independent components, and the pressure relief member 232 is connected to the first wall 231a by welding, bonding or clamping.

[0155] By setting the pressure relief member 232 and the first wall 231a as a split structure, and setting a pressure relief hole 2312 on the first wall 231a, the pressure relief member 232 can cover the pressure relief hole 2312 to achieve the function of releasing the internal pressure of the battery cell 20. This structure facilitates the setting and installation of the pressure relief member 232 on the first wall 231a, helps reduce the difficulty of assembly, and facilitates the later maintenance and replacement of the pressure relief member 232.

[0156] According to some embodiments of the present application, referring to Figures 12 and 13, Figure 12 is a cross-sectional view of a pressure relief member 232 connected to a first wall 231a according to further embodiments of the present application, and Figure 13 is a partially enlarged view of the pressure relief member 232 connected to the first wall 231a at point B shown in Figure 12. The first side surface 2311 is provided with a receiving groove 2313, and a pressure relief hole 2312 extends through the bottom surface of the receiving groove 2313. The receiving groove 2313 is used to accommodate at least a portion of the pressure relief member 232.

[0157] The first side surface 2311 is provided with an accommodating groove 2313 , that is, the accommodating groove 2313 is provided on the first side surface 2311 of the first wall 231a facing the interior of the battery cell 20 , and the pressure relief hole 2312 can be connected to the interior of the battery cell 20 through the accommodating groove 2313 .

[0158] The accommodating groove 2313 is used to accommodate at least part of the pressure relief member 232, that is, the pressure relief member 232 can be entirely accommodated in the accommodating groove 2313, or it can be partially accommodated in the accommodating groove 2313. For example, in Figure 13, part of the pressure relief member 232 extends into the pressure relief hole 2312, and the other parts of the pressure relief member 232 are all accommodated in the accommodating groove 2313, so as to achieve that the protrusion 2322 of the pressure relief member 232 does not exceed the first side surface 2311 in the thickness direction X of the first wall, that is, the protrusion 2322 of the pressure relief member 232 does not exceed the first side surface 2311 in the first direction Y.

[0159] By providing an accommodating groove 2313 on the first side surface 2311 of the first wall 231a, the pressure relief member 232 can be accommodated in the accommodating groove 2313. Thus, this structure ensures that the protrusion 2322 of the pressure relief member 232 does not exceed the first side surface 2311 of the first wall 231a in the thickness direction X of the first wall. The structure is simple and easy to implement.

[0160] In some embodiments, referring to Figures 12 and 13 , the receiving groove 2313 includes a first groove 2313a and a second groove 2313b. The second groove 2313b is disposed on the bottom surface of the first groove 2313a. The pressure relief hole 2312 extends through the bottom surface of the second groove 2313b. The pressure relief member 232 is mounted in the second groove 2313b and abuts against the bottom surface of the second groove 2313b. The protrusion 2322 is accommodated in the first groove 2313a.

[0161] Among them, the second groove 2313b is arranged on the bottom surface of the first groove 2313a, and the pressure relief hole 2312 passes through the bottom surface of the second groove 2313b, that is, the pressure relief hole 2312 is connected to the first groove 2313a through the second groove 2313b, that is, the accommodating groove 2313 is a stepped groove structure arranged on the first side surface 2311, and in the thickness direction X of the first wall, the first groove 2313a is closer to the interior of the battery cell 20 than the second groove 2313b, so that the second groove 2313b is arranged on the bottom surface of the first groove 2313a, and the pressure relief hole 2312 passes through the bottom surface of the second groove 2313b, that is, the second groove 2313b and the first groove 2313a are arranged along the first direction Y.

[0162] The pressure relief member 232 is installed in the second groove 2313b and abuts against the bottom surface of the second groove 2313b, that is, the pressure relief member 232 is connected to the bottom surface or the side surface of the second groove 2313b, so that the pressure relief member 232 is installed in the second groove 2313b, and the pressure relief member 232 and the bottom surface of the second groove 2313b abut against each other.

[0163] The protrusion 2322 is accommodated in the first groove 2313a, that is, the protrusion 2322 extends out of the second groove 2313b in the thickness direction X of the first wall and is accommodated in the first groove 2313a, so that the protrusion 2322 does not exceed the first side surface 2311 in the thickness direction X of the first wall.

[0164] It should be noted that in the embodiment where the accommodating groove 2313 is provided on the first side surface 2311 and the accommodating groove 2313 is provided with a stepped groove structure formed by a first groove 2313a and a second groove 2313b, the first surface 2323 of the pressure relief member 232 facing the interior of the battery cell 20 may be provided with a groove 2324, or the first surface 2323 of the pressure relief member 232 facing the interior of the battery cell 20 may not be provided with a groove 2324, that is, the protrusion 2322 protrudes from the surface of the pressure relief member 232 facing the interior of the battery cell 20. For example, in FIG13 , the pressure relief member 232 has a structure where the first surface 2323 does not have a groove 2324.

[0165] The accommodating groove 2313 includes a first groove 2313a and a second groove 2313b arranged in sequence along the thickness direction X of the first wall. The second groove 2313b is arranged on the groove bottom surface of the first groove 2313a, and the pressure relief hole 2312 passes through the groove bottom surface of the second groove 2313b. That is, in the thickness direction X of the first wall, the second groove 2313b is arranged between the first groove 2313a and the pressure relief hole 2312, so that by installing the pressure relief member 232 in the second groove 2313b and accommodating the protrusion 2322 of the pressure relief member 232 in the first groove 2313a, it is achieved that the protrusion 2322 does not exceed the first side surface 2311 of the first wall 231a in the thickness direction X of the first wall. This structure is simple and easy to assemble.

[0166] According to some embodiments of the present application, referring to Figures 14 and 15 , Figure 14 is a cross-sectional view of a pressure relief member 232 connected to a first wall 231a according to yet other embodiments of the present application, and Figure 15 is a partially enlarged view of the pressure relief member 232 connected to the first wall 231a at point C shown in Figure 14 . Along the thickness direction X of the first wall, the first wall 231a has a second side surface 2314 disposed opposite the first side surface 2311. The second side surface 2314 is provided with a receiving groove 2313. A pressure relief hole 2312 extends through the bottom surface of the receiving groove 2313. The receiving groove 2313 is used to accommodate at least a portion of the pressure relief member 232.

[0167] The second side surface 2314 is provided with a receiving groove 2313 , that is, the receiving groove 2313 is provided on the second side surface 2314 of the first wall 231a away from the interior of the battery cell 20 , and the pressure relief hole 2312 is connected with the external environment through the receiving groove 2313 , and the pressure relief hole 2312 passes through the first side surface 2311 .

[0168] The accommodating groove 2313 is used to accommodate at least part of the pressure relief member 232, that is, the pressure relief member 232 can be entirely accommodated in the accommodating groove 2313, or it can be partially accommodated in the accommodating groove 2313. For example, in Figure 15, part of the pressure relief member 232 extends into the pressure relief hole 2312, and the other parts of the pressure relief member 232 are all accommodated in the accommodating groove 2313, so as to achieve that the protrusion 2322 of the pressure relief member 232 does not exceed the first side surface 2311 in the thickness direction X of the first wall, that is, the protrusion 2322 of the pressure relief member 232 does not exceed the first side surface 2311 in the first direction Y.

[0169] By providing an accommodating groove 2313 on the second side surface 2314 of the first wall 231a away from the first side surface 2311, the pressure relief member 232 can be accommodated in the accommodating groove 2313, so that the pressure relief member 232 is installed on the side of the first wall 231a away from the interior of the battery cell 20. In this way, this structure is adopted to ensure that the protrusion 2322 of the pressure relief member 232 does not exceed the first side surface 2311 of the end cover 231 in the thickness direction X of the first wall. The structure is simple and easy to implement.

[0170] In some embodiments, as shown in Figures 14 and 15 , the receiving groove 2313 includes a third groove 2313c and a fourth groove 2313d. The fourth groove 2313d is disposed on the bottom surface of the third groove 2313c. The pressure relief hole 2312 extends through the bottom surface of the fourth groove 2313d. The pressure relief member 232 is mounted in the fourth groove 2313d and abuts against the bottom surface of the fourth groove 2313d. The protrusion 2322 is accommodated in the pressure relief hole 2312.

[0171] Among them, the fourth groove 2313d is arranged on the bottom surface of the third groove 2313c, and the pressure relief hole 2312 passes through the bottom surface of the fourth groove 2313d, that is, the pressure relief hole 2312 is connected with the third groove 2313c through the fourth groove 2313d, that is, the accommodating groove 2313 is a stepped groove structure arranged on the second side surface 2314, and in the thickness direction X of the first wall, the third groove 2313c is farther away from the interior of the battery cell 20 than the fourth groove 2313d, so that the fourth groove 2313d is arranged on the bottom surface of the third groove 2313c, and the pressure relief hole 2312 passes through the bottom surface of the fourth groove 2313d, that is, the third groove 2313c and the fourth groove 2313d are arranged along the first direction Y.

[0172] The pressure relief member 232 is installed in the fourth groove 2313d and abuts against the bottom surface of the fourth groove 2313d, that is, the pressure relief member 232 is connected to the bottom surface or the side surface of the fourth groove 2313d, so that the pressure relief member 232 is installed in the fourth groove 2313d, and the pressure relief member 232 and the bottom surface of the fourth groove 2313d abut against each other.

[0173] The protrusion 2322 is accommodated in the pressure relief hole 2312, that is, the protrusion 2322 extends out of the bottom surface of the fourth groove 2313d in the thickness direction X of the first wall, and is accommodated in the pressure relief hole 2312, so as to ensure that the protrusion 2322 does not exceed the first side surface 2311 in the thickness direction X of the first wall, that is, the protrusion 2322 does not exceed the first side surface 2311 in the first direction Y.

[0174] It should be noted that in the embodiment where the accommodating groove 2313 is provided on the second side surface 2314 and the accommodating groove 2313 is provided with a stepped groove structure formed by a third groove 2313c and a fourth groove 2313d, the first surface 2323 of the pressure relief member 232 facing the interior of the battery cell 20 may be provided with a groove 2324, or the first surface 2323 of the pressure relief member 232 facing the interior of the battery cell 20 may not be provided with a groove 2324, that is, the protrusion 2322 protrudes from the surface of the pressure relief member 232 facing the interior of the battery cell 20. For example, in FIG. 15 , the pressure relief member 232 has a structure where the first surface 2323 does not have a groove 2324.

[0175] The accommodating groove 2313 includes a third groove 2313c and a fourth groove 2313d which are arranged in sequence along the thickness direction X of the first wall. The fourth groove 2313d is arranged on the bottom surface of the third groove 2313c, and the pressure relief hole 2312 passes through the bottom surface of the fourth groove 2313d. That is, in the thickness direction X of the first wall, the fourth groove 2313d is arranged between the third groove 2313c and the pressure relief hole 2312, so that by installing the pressure relief member 232 in the fourth groove 2313d and accommodating the protrusion 2322 of the pressure relief member 232 in the pressure relief hole 2312, it is achieved that the protrusion 2322 does not exceed the first side surface 2311 of the first wall 231a in the thickness direction X of the first wall. This structure is simple and easy to assemble.

[0176] It should be noted that in the above-described structures, the protrusion 2322 of the pressure relief member 232 is configured to not extend beyond the first side surface 2311 in the thickness direction X of the first wall, thereby effectively protecting the weak structure of the pressure relief member 232. In other embodiments, for example, referring to Figures 16 and 17, Figure 16 is a cross-sectional view of the pressure relief member 232 connected to the first wall 231a according to other embodiments of the present application, and Figure 17 is a partial enlarged view of the pressure relief member 232 connected to the first wall 231a shown in Figure 16. The protrusion 2322 of the pressure relief member 232 protrudes from the surface of the pressure relief member 232 facing the interior of the battery cell 20 in the thickness direction X of the first wall, that is, the protrusion 2322 of the pressure relief member 232 protrudes from the pressure relief member 232 in the first direction Y. The end cover assembly 23 may also include a mounting member 233, which is arranged on the side of the pressure relief member 232 facing the interior of the battery cell 20. The protrusion 2322 does not exceed the mounting member 233 in the first direction Y, so as to better protect the protrusion 2322, thereby reducing the wear or damage of the protrusion 2322 during the production and assembly process of the battery cell 20.

[0177] The mounting member 233 can be connected to the first wall 231a or to the surface of the pressure relief member 232 facing the interior of the battery cell 20. For example, in FIG17 , the mounting member 233 is connected to the surface of the pressure relief member 232 facing the interior of the battery cell 20. The mounting member 233 can be assembled in various ways, such as by bonding, clamping, welding, etc.

[0178] The mounting member 233 is made of insulating material. For example, the mounting member 233 may be made of polyethylene, polypropylene, plastic, rubber, etc.

[0179] In some embodiments, there is one mounting member 233, and the mounting member 233 surrounds the outer side of the protrusion 2322. The mounting member 233 can be a closed surround or a non-closed surround, such as a half-circle or 2 / 3 circle.

[0180] In some embodiments, a plurality of mounting members 233 may be provided, and the plurality of mounting members 233 may be arranged at intervals around the protrusion 2322 , that is, the plurality of mounting members 233 may be arranged around the protrusion 2322 .

[0181] In the embodiment where the pressure relief member 232 is provided with the mounting member 233 , along the first direction Y, the protrusion 2322 may extend beyond the first side surface 2311 of the first wall 231 a or may not extend beyond the first side surface 2311 of the first wall 231 a .

[0182] Similarly, the surface of the mounting member 233 facing the pressure relief member 232 and the first side surface 2311 of the first wall 231a can be coplanar or staggered. When the surface of the mounting member 233 facing the pressure relief member 232 and the first side surface 2311 of the first wall 231a are staggered, the surface of the mounting member 233 facing the pressure relief member 232 can be closer to the interior of the battery cell 20 in the thickness direction X of the first wall than the first side surface 2311 of the first wall 231a, or the surface of the mounting member 233 facing the pressure relief member 232 can be farther away from the interior of the battery cell 20 in the thickness direction X of the first wall than the first side surface 2311 of the first wall 231a.

[0183] According to some embodiments of the present application, the battery cell 20 may also have other structures, for example, the weak structure is a thinned region of the pressure relief member 232. In the thickness direction X of the first wall, the surface of the thinned region of the pressure relief member 232 near the interior of the battery cell 20 does not extend beyond the first side surface 2311 in the direction facing the interior of the battery cell 20.

[0184] Among them, the surface of the thinned area of ​​the pressure relief member 232 close to the interior of the battery cell 20 does not exceed the first side surface 2311 along the direction facing the interior of the battery cell 20, that is, the thinned area of ​​the pressure relief member 232 does not exceed the first side surface 2311 as a whole in the thickness direction X of the first wall toward the interior of the battery cell 20, that is, in the first direction Y, the surface of the thinned area of ​​the pressure relief member 232 facing the interior of the battery cell 20 does not exceed the first side surface 2311 of the first wall 231a.

[0185] By thinning the thickness of a portion of the pressure relief member 232, the thinned region of the pressure relief member 232 becomes a weak structure for relieving the internal pressure of the battery cell 20, resulting in a simple structure and low processing difficulty. Furthermore, by setting the surface of the thinned region of the pressure relief member 232 near the interior of the battery cell 20 so as not to extend beyond the first side surface 2311 in the first direction Y, the thinned region of the pressure relief member 232 does not extend beyond the first side surface 2311 in the thickness direction X of the first wall. This effectively protects the thinned region of the pressure relief member 232 and mitigates wear or damage to the thinned region of the pressure relief member 232 during the production and assembly of the battery cell 20.

[0186] According to some embodiments of the present application, as shown in Figures 6 and 7 , the battery cell 20 may further include a protective member 234. The protective member 234 is disposed on a side of the first wall 231a facing away from the interior of the battery cell 20 and covers the pressure relief hole 2312. The protective member 234 is used to protect the pressure relief member 232.

[0187] The protective member 234 protects the pressure relief member 232 by covering the pressure relief hole 2312. The protective member 234 can reduce damage to the pressure relief member 232 caused by the external environment of the battery cell 20. The protective member 234 can be made of a variety of materials, such as polypropylene, rubber, plastic, or silicone.

[0188] The battery cell 20 is also provided with a protective member 234 for protecting the pressure relief member 232. The protective member 234 is arranged on the side of the first wall 231a away from the interior of the battery cell 20, so as to better protect the pressure relief member 232, thereby alleviating the risk of the pressure relief member 232 being worn or damaged by other components during later use, so as to ensure the stability and reliability of the use of the pressure relief member 232.

[0189] According to some embodiments of the present application, please continue to refer to Figures 6 and 7. Along the thickness direction X of the first wall, the first wall 231a has a second side surface 2314 arranged opposite to the first side surface 2311, and a mounting groove 2315 is provided on the second side surface 2314. At least a portion of the protective member 234 is accommodated in the mounting groove 2315.

[0190] The mounting groove 2315 is arranged on the second side 2314 of the end cover 231 away from the first side 2311, and the pressure relief hole 2312 passes through the bottom surface of the mounting groove 2315, so that the protective member 234 can cover the pressure relief hole 2312 when accommodated in the mounting groove 2315.

[0191] At least a portion of the protection member 234 is accommodated in the installation slot 2315 , that is, the protection member 234 may be entirely located in the installation slot 2315 , or may partially extend out of the installation slot 2315 .

[0192] It should be noted that, in the embodiment where the accommodating groove 2313 on the first wall 231a is arranged on the second side surface 2314 of the first wall 231a, the protective member 234 can be directly arranged on the second side surface 2314, and the protective member 234 covers the accommodating groove 2313, so as to protect the pressure relief member 232. Alternatively, a mounting groove 2315 can be provided on the second side surface 2314, and the accommodating groove 2313 is provided on the bottom surface of the mounting groove 2315, that is, the pressure relief hole 2312 is connected to the mounting groove 2315 through the accommodating groove 2313, so that the protective member 234 can be accommodated in the mounting groove 2315 to protect the pressure relief member 232.

[0193] By providing an installation groove 2315 for accommodating the protective member 234 on the second side 2314, the protective member 234 can be accommodated in the installation groove 2315, thereby providing better protection for the protective member 234, thereby alleviating the phenomenon of the protective member 234 being damaged by the external environment during later use, thereby helping to extend the service life of the protective member 234.

[0194] In some embodiments, as shown in FIG. 7 , along the thickness direction X of the first wall, the protection member 234 does not extend beyond the second side surface 2314 .

[0195] The protective member 234 does not extend beyond the second side surface 2314 , that is, in a direction away from the first direction Y, the protective member 234 does not extend beyond the second side surface 2314 , that is, the protective member 234 is entirely accommodated in the installation groove 2315 .

[0196] By setting the protective member 234 as the second side surface 2314 that does not extend beyond the first wall 231a in the thickness direction X of the first wall, that is, the protective member 234 is entirely accommodated in the installation groove 2315, the battery cell 20 adopting this structure can enhance the protection effect of the protective member 234 to reduce the risk of damage to the protective member 234 during use.

[0197] According to some embodiments of the present application, referring to Figures 3, 4, and 5, the housing includes a shell 21 and an end cap assembly 23. The shell 21 has an opening 211, and the end cap assembly 23 has an end cap 231, which covers the opening 211. The first wall 231a is the end cap 231.

[0198] The first wall 231 a is the end cover 231 , that is, the pressure relief member 232 is disposed on the end cover 231 of the end cover assembly 23 .

[0199] In some embodiments, the first wall 231 a may also be the shell 21 , that is, the pressure relief member 232 may also be disposed on the shell 21 .

[0200] The battery cell 20 with this structure facilitates the disposition of the pressure relief member 232 on the housing, which helps to reduce the difficulty of disposing the pressure relief member 232 on the housing.

[0201] According to some embodiments of the present application, referring to Figures 3 and 4, the end cap assembly 23 may further include an electrode terminal 235, a connector 236, and a first insulating member 237. The electrode terminal 235 is insulated and mounted on the end cap 231. The connector 236 is disposed on a side of the end cap 231 facing away from the interior of the battery cell 20 and is connected to the electrode terminal 235. The first insulating member 237 is disposed between the connector 236 and the end cap 231 to insulate and isolate the connector 236 from the end cap 231.

[0202] Among them, the electrode terminal 235 plays the role of outputting or inputting electrical energy of the battery cell 20. The end cover 231 is provided with a lead-out hole 2316 for installing the electrode terminal 235. Along the thickness direction X of the first wall, the electrode terminal 235 is inserted into the lead-out hole 2316, and the lead-out holes 2316 are extended from both ends of the electrode terminal 235 respectively. The end of the electrode terminal 235 facing the interior of the battery cell 20 is used to be connected to the pole ear 221 of the electrode assembly 22 to realize the electrical connection between the electrode terminal 235 and the electrode assembly 22. The end of the electrode terminal 235 facing away from the interior of the battery cell 20 serves as the output pole of the battery cell 20.

[0203] The electrode terminal 235 is insulated and mounted on the end cover 231 , that is, no electrical connection is formed between the electrode terminal 235 and the end cover 231 .

[0204] For example, in Figures 4 and 5 , there are two electrode terminals 235, and correspondingly, there are two lead-out holes 2316 on the end cap 231. Each electrode terminal 235 is disposed within one lead-out hole 2316. Both electrode terminals 235 are used to electrically connect to the tabs 221 of the electrode assembly 22 to serve as the positive output electrode or the negative output electrode of the battery cell 20. Of course, in other embodiments, the number of electrode terminals 235 may be one, three, or four, etc., and correspondingly, the lead-out holes 2316 are provided in a one-to-one correspondence with the electrode terminals 235.

[0205] The connector 236 is used to connect the electrode terminal 235 to secure the electrode terminal 235 and other components to the end cap 231. Exemplarily, the connector 236 is a rivet block. In FIG4 , the connector 236 and both electrode terminals 235 are riveted to each other, thereby fastening the electrode terminal 235 and the first insulating member 237 to the end cap 231.

[0206] The first insulating member 237 is disposed between the end cap 231 and the connector 236 in the thickness direction X of the first wall to separate the end cap 231 and the connector 236, thereby achieving insulation isolation between the end cap 231 and the connector 236. The first insulating member 237 can be made of various materials, such as plastic, rubber, or silicone.

[0207] In some embodiments, as shown in Figure 5, the end cap assembly 23 may further include a seal 238, which is sleeved on the outside of the electrode terminal 235, and at least a portion of the seal 238 is located in the lead-out hole 2316 to seal the gap between the electrode terminal 235 and the hole wall of the lead-out hole 2316.

[0208] Among them, at least part of the seal 238 is located in the lead-out hole 2316, that is, the seal 238 surrounds the outside of the electrode terminal 235, and the seal 238 can be located entirely in the lead-out hole 2316, or partially in the lead-out hole 2316, so as to seal the gap between the electrode terminal 235 and the wall of the lead-out hole 2316, thereby reducing the risk of electrolyte leakage in the battery cell 20.

[0209] For example, in FIG5 , the sealing member 238 is a sealing ring, and the material of the sealing member 238 may be rubber, silicone, plastic, or the like.

[0210] An electrode terminal 235 is insulated and mounted on the end cap 231. The electrode terminal 235 is connected to a connector 236 disposed on the side of the end cap 231 facing away from the interior of the battery cell 20. This secures the electrode terminal 235 to the end cap 231 and facilitates assembly. Thus, electrical energy can be input or output from the battery cell 20 via the electrode terminal 235 disposed on the end cap 231. Furthermore, a first insulating member 237 is disposed between the connector 236 and the end cap 231. This first insulating member 237 provides insulation between the connector 236 and the end cap 231, thereby reducing the risk of short circuits in the battery cell 20.

[0211] According to some embodiments of the present application, as shown in Figures 4 and 5, the end cap assembly 23 may further include a current collecting member 239 and a second insulating member 240. The current collecting member 239 is disposed on a side of the end cap 231 facing the interior of the battery cell 20, and the current collecting member 239 connects the electrode terminal 235 and the electrode assembly 22. The second insulating member 240 is disposed between the current collecting member 239 and the end cap 231 to insulate and isolate the current collecting member 239 from the end cap 231.

[0212] The current collecting member 239 connects the electrode terminal 235 and the tab 221 of the electrode assembly 22 to achieve electrical connection between the electrode terminal 235 and the electrode assembly 22. The current collecting member 239 can be made of various materials, such as copper, iron, aluminum, or steel.

[0213] The second insulating member 240 is disposed between the current collecting member 239 and the end cap 231 along the thickness direction X of the first wall to insulate and isolate the current collecting member 239 from the end cap 231. The second insulating member 240 can also be made of various materials, such as rubber, plastic or the like.

[0214] A current collecting member 239 is provided on the side of the end cap 231 facing away from the connector 236. This current collecting member 239 connects the electrode terminal 235 to the electrode assembly 22, thereby achieving electrical connection between the electrode assembly 22 and the electrode terminal 235. This simple structure facilitates assembly. Furthermore, a second insulating member 240 is provided between the current collecting member 239 and the end cap 231. This second insulating member 240 provides insulation between the current collecting member 239 and the end cap 231, thereby reducing the risk of short circuits in the battery cells 20.

[0215] According to some embodiments of the present application, a battery 100 is further provided. The battery 100 includes a battery cell 20 according to any of the above solutions.

[0216] According to some embodiments of the present application, an energy storage device is further provided, and the energy storage device includes the battery 100 of any of the above solutions.

[0217] Exemplarily, the energy storage device may be an energy storage cabinet or an energy storage container, etc.

[0218] According to some embodiments of the present application, an electrical device is further provided, comprising the battery cell 20 of any of the above solutions, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0219] The power-consuming device may be any of the aforementioned devices or systems using the battery cell 20 .

[0220] According to some embodiments of the present application, as shown in Figures 4 to 10, the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and an end cap assembly 23. The housing 21 has an opening 211, and the electrode assembly 22 is accommodated in the housing 21. The end cap assembly 23 includes an end cap 231, a pressure relief member 232, a protective member 234, an electrode terminal 235, a connector 236, a first insulating member 237, a current collecting member 239, and a second insulating member 240. The end cover 231 covers the opening 211. The end cover 231 is a first wall 231a. Along the thickness direction X of the first wall, the end cover 231 has a first side surface 2311 and a second side surface 2314 that are oppositely arranged. The first side surface 2311 is arranged facing the interior of the battery cell 20. A receiving groove 2313 is provided on the first side surface 2311, and a mounting groove 2315 is provided on the second side surface 2314. A pressure relief hole 2312 is provided on the end cover 231. The pressure relief hole 2312 passes through the bottom surface of the receiving groove 2313 and the bottom surface of the mounting groove 2315 at both ends in the thickness direction X of the first wall respectively. The pressure relief member 232 is disposed within the receiving groove 2313 and covers the pressure relief hole 2312. A notched groove 2321 is provided on the side of the pressure relief member 232 facing away from the interior of the battery cell 20, along the thickness direction X of the first wall. A protrusion 2322 is formed on the pressure relief member 232 facing the interior of the battery cell 20, corresponding to the notched groove 2321. The pressure relief member 232 has a first surface 2323 facing the interior of the battery cell 20. The first surface 2323 is coplanar with the first side surface 2311. A groove 2324 is provided on the first surface 2323. The protrusion 2322 is received within the groove 2324 and does not extend beyond the first surface 2323 in the thickness direction X of the first wall. A protective member 234 is disposed within the mounting groove 2315 and covers the pressure relief hole 2312. The protective member 234 does not extend beyond the second side surface 2314 in the thickness direction X of the first wall. The electrode terminal 235 is insulated and mounted to the end cap 231. Along the thickness direction X of the first wall, a connector 236 is disposed on a side of the end cap 231 facing away from the interior of the battery cell 20, and the connector 236 is connected to the electrode terminal 235. A first insulating member 237 is disposed between the connector 236 and the end cap 231 to insulate and isolate the connector 236 from the end cap 231. Along the thickness direction X of the first wall, a current collecting member 239 is disposed on a side of the end cap 231 facing the interior of the battery cell 20, and the current collecting member 239 is connected to the electrode terminal 235. The current collecting member 239 is used to electrically connect to the electrode assembly 22. A second insulating member 240 is disposed between the current collecting member 239 and the end cap 231 to insulate and isolate the current collecting member 239 from the end cap 231.

[0221] 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.

[0222] 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 having a first wall, the first wall having a first side facing the interior of the battery cell, the housing being configured to accommodate an electrode assembly; as well as a pressure relief member, disposed on the first wall; The pressure relief member has a weak structure, and along the thickness direction of the first wall, the weak structure does not extend beyond the first side surface in a direction facing the interior of the battery cell.

2. The battery cell according to claim 1, wherein: The weak structure is the area where the pressure relief member is provided with the notched groove; The notched groove is arranged on the side of the pressure relief member facing away from the interior of the battery cell, and the pressure relief member is formed with a protrusion at a position corresponding to the notched groove on the side facing the interior of the battery cell, and the protrusion does not exceed the first side surface along the direction facing the interior of the battery cell.

3. The battery cell according to claim 2, wherein: Along the thickness direction of the first wall, a distance between the protrusion and the first side surface is H, satisfying H>0 mm.

4. The battery cell according to claim 2 or 3, wherein: The pressure relief member has a first surface facing the interior of the battery cell. A groove is provided on the first surface. At least a portion of the protrusion is accommodated in the groove.

5. The battery cell according to claim 4, wherein: Along the thickness direction of the first wall, the protrusion does not exceed the first surface. The battery cell according to claim 5 , wherein: The first surface is coplanar with the first side surface; or Along a thickness direction of the first wall, the first surface is farther away from the interior of the battery cell than the first side surface.

7. The battery cell according to any one of claims 4 to 6, wherein: The pressure relief member comprises: A pressure relief portion is provided with the notched groove, and the protrusion is formed on a side of the pressure relief portion facing the interior of the battery cell at a position corresponding to the notched groove; A mounting portion connected to the first wall, the mounting portion being arranged around the pressure relief portion; Wherein, the thickness of the mounting portion is greater than the thickness of the pressure relief portion, and the mounting portion and the pressure relief portion are enclosed to form the groove.

8. The battery cell according to claim 7, wherein: The thickness of the mounting portion is L1, which satisfies 0.1 mm ≤ L1 ≤ 0.4 mm.

9. The battery cell according to claim 7 or 8, wherein: The minimum thickness of the pressure relief portion where the notch groove is provided is L2, satisfying 0.03 mm ≤ L2 ≤ 0.15 mm.

10. The battery cell according to any one of claims 7 to 9, wherein: The scored groove is an annular groove, and along the thickness direction of the first wall, the area of ​​the pressure relief portion located inside the scored groove is arched in a direction away from the interior of the battery cell.

11. The battery cell according to any one of claims 7 to 10, wherein: The pressure relief member is a circular structure.

12. The battery cell according to any one of claims 2 to 11, wherein: The pressure relief member and the first wall are separate structures. A pressure relief hole is provided on the first wall, and the pressure relief member covers the pressure relief hole.

13. The battery cell according to claim 12, wherein: The first side surface is provided with an accommodating groove, the pressure relief hole runs through the bottom surface of the accommodating groove, and the accommodating groove is used to accommodate at least a portion of the pressure relief component.

14. The battery cell according to claim 13, wherein: The accommodating groove includes a first groove and a second groove, the second groove is arranged on the groove bottom surface of the first groove, and the pressure relief hole passes through the groove bottom surface of the second groove; The pressure relief member is installed in the second groove and abuts against the bottom surface of the second groove, and the protrusion is accommodated in the first groove.

15. The battery cell according to claim 12, wherein: Along the thickness direction of the first wall, the first wall has a second side surface arranged opposite to the first side surface, and the second side surface is provided with a receiving groove. The pressure relief hole passes through the bottom surface of the receiving groove, and the receiving groove is used to accommodate at least part of the pressure relief component.

16. The battery cell according to claim 15, wherein: The accommodating groove includes a third groove and a fourth groove, the fourth groove is arranged on the groove bottom surface of the third groove, and the pressure relief hole passes through the groove bottom surface of the fourth groove; The pressure relief member is installed in the fourth groove and abuts against the bottom surface of the fourth groove, and the protrusion is accommodated in the pressure relief hole.

17. The battery cell according to claim 1, wherein The weak structure is a region where the thickness of the pressure relief component is reduced; In the thickness direction of the first wall, a surface of the pressure relief member in a region where the thickness is reduced and close to the interior of the battery cell does not extend beyond the first side surface in a direction facing the interior of the battery cell.

18. The battery cell according to any one of claims 12 to 16, wherein: The battery cell further comprises: A protective member is provided on a side of the first wall facing away from the interior of the battery cell, and the protective member covers the pressure relief hole, and is used to protect the pressure relief member.

19. The battery cell according to claim 18, wherein: Along the thickness direction of the first wall, the first wall has a second side surface arranged opposite to the first side surface, and a mounting groove is provided on the second side surface. At least a portion of the protective member is accommodated in the mounting groove.

20. The battery cell according to claim 19, wherein Along the thickness direction of the first wall, the protection member does not exceed the second side surface.

21. The battery cell according to any one of claims 1 to 20, wherein: The housing comprises: a housing having an opening; An end cap assembly comprises an end cap, wherein the end cap covers the opening; Wherein, the first wall is the end cover.

22. The battery cell according to claim 21, wherein The end cap assembly further comprises: an electrode terminal, insulated and mounted on the end cap; a connector, disposed on a side of the end cover facing away from the interior of the battery cell, and connected to the electrode terminal; The first insulating member is disposed between the connecting member and the end cover to insulate and isolate the connecting member and the end cover.

23. The battery cell according to claim 22, wherein: The end cap assembly further comprises: a current collecting member disposed on a side of the end cover facing the interior of the battery cell, and the current collecting member connecting the electrode terminal and the electrode assembly; The second insulating member is disposed between the current collecting member and the end cover to insulate and isolate the current collecting member from the end cover.

24. A battery comprising the battery cell according to any one of claims 1 to 23.

25. An energy storage device comprising the battery according to claim 24.

26. An electrical device comprising the battery cell according to any one of claims 1 to 23.

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