Battery cell, manufacturing method and system thereof, battery and electric device

Abstract

The embodiments of the present application provide a battery cell and its manufacturing method and manufacturing system, a battery, and an electrical device. The battery cell includes: a shell having an opening; an electrode assembly housed in the shell, the electrode assembly being provided with a first pole ear at the end facing the opening; and an end cover for covering the opening, the end cover including a cover body and a first protrusion connected to the cover body, the cover body being provided with a weak portion, and the end cover being configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure. The first protrusion protrudes from the cover body in a direction facing the electrode assembly and is used to support the first pole ear so that a clearance gap for avoiding the weak portion is formed between the first pole ear and the cover body. The present application can reduce the risk of the first pole ear squeezing the weak portion and improve the battery cell and safety performance.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and more particularly, to a battery cell and a manufacturing method and system thereof, a battery, and an electrical device. Background Art

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric bicycles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, and secondary alkaline zinc-manganese battery cells.

[0003] In the development of battery technology, in addition to improving the performance of battery cells, safety is also an issue that cannot be ignored. If the safety of a battery cell cannot be guaranteed, the battery cell will be unusable. Therefore, how to enhance the safety of battery cells is a technical issue that needs to be addressed urgently in battery technology. Summary of the Invention

[0004] The present application provides a battery cell, a manufacturing method and a manufacturing system thereof, a battery, and an electrical device, which can improve the safety of the battery cell.

[0005] In a first aspect, embodiments of the present application provide a battery cell, comprising: a housing having an opening; an electrode assembly housed within the housing, the electrode assembly having a first tab disposed at one end facing the opening; and an end cap for covering the opening, the end cap comprising a cap body and a first protrusion connected to the cap body, the cap body being provided with a weakened portion, the end cap being configured to rupture along the weakened portion to release the internal pressure of the battery cell when the internal pressure of the battery cell reaches a threshold. The first protrusion protrudes from the cap body in a direction facing the electrode assembly and supports the first tab, thereby forming a clearance gap between the first tab and the cap body to avoid the weakened portion.

[0006] In the above solution, the first protrusion protruding from the cover body can support the first tab, thereby reducing the amplitude of the electrode assembly's shaking when the battery cell vibrates and improving the stability of the electrode assembly. The first protrusion supports the first tab, forming a clearance between the first tab and the cover body to avoid the weak part. This reduces the risk of the electrode assembly squeezing the weak part, reduces the possibility of failure of the weak part, and improves the safety of the battery cell.

[0007] In some embodiments, a first recessed portion is formed on the end cover at a position corresponding to the first protrusion, which is recessed from the outer surface of the cover body in a direction facing the electrode assembly, and the bottom surface of the first recessed portion is closer to the first electrode tab than the inner surface of the cover body.

[0008] The above solution ensures that the first protrusion protrudes beyond the cover body to more effectively support the first tab, increase the size of the clearance along the thickness direction, and further reduce the risk of the electrode assembly squeezing the weak part. At the same time, while ensuring the protrusion of the first protrusion, the embodiment of the present application further ensures the degree of concavity of the first concave portion, thereby increasing the elasticity of the first protrusion and reducing the risk of the first protrusion crushing the first tab during assembly.

[0009] In some embodiments, the first protrusion is used to abut against and weld the first electrode tab to achieve electrical connection between the end cap and the first electrode tab.

[0010] In the above solution, the end cover can be directly electrically connected to the first tab via the first protrusion, thereby simplifying the structure of the battery cell.

[0011] In some embodiments, the battery cell further includes a current collecting member disposed between the end cap and the first electrode tab. The current collecting member is configured to connect the end cap and the first electrode tab to achieve electrical connection between the end cap and the first electrode tab. A clearance gap is located between the current collecting member and the cover body in the thickness direction of the end cap.

[0012] The first protrusion protrudes from the cover body, separating the cover body from the first tab in the thickness direction. If the end cap and the first tab were directly connected, the first tab would only be connected to the first protrusion of the end cap, which would restrict the area of ​​the first tab capable of directly transmitting current to the first protrusion. In the above solution, by providing a current collecting member to connect the first tab and the end cap, the area of ​​the first tab capable of directly transmitting current is no longer restricted by the first protrusion. The current from the first tab can be funneled into the end cap through the current collecting member. This reduces the difference in the conductive path between different areas of the first tab and the end cap, improving the uniformity of the current density of the first pole sheet, reducing internal resistance, and enhancing the current handling capacity and charging efficiency of the battery cell. The clearance gap between the current collecting member and the cover body reduces the risk of the current collecting member squeezing the weak portion and the possibility of the current collecting member blocking the exhaust channel if the weak portion ruptures, ensuring smooth exhaust and improving safety.

[0013] In some embodiments, the current collecting member covers the weak portion along a thickness direction of the end cap to separate the weak portion from the first electrode tab.

[0014] In the above solution, the current collecting member can separate the weak portion from the first electrode tab to reduce the number of active particles in the electrode assembly falling onto the weak portion, thereby reducing the risk of corrosion of the weak portion.

[0015] In some embodiments, the first protrusion surrounds the outer side of the cover body, and the current collecting member is used to connect the cover body and the first electrode tab to achieve electrical connection between the end cap and the first electrode tab.

[0016] In some embodiments, the current collecting member includes a first current collecting portion and a second current collecting portion connected to the first current collecting portion. The first current collecting portion is used to connect to the first electrode tab to electrically connect the current collecting member and the first electrode tab, and the second current collecting portion is used to connect to the cover body to electrically connect the current collecting member and the end cap. The first current collecting portion is provided protruding from the surface of the second current collecting portion facing the electrode assembly. A relief recess is formed at a position of the current collecting member corresponding to the first current collecting portion. The recess is recessed from the surface of the second current collecting portion facing away from the electrode assembly in a direction facing the electrode assembly, thereby forming a relief gap between the current collecting member and the cover body.

[0017] In the above solution, the provision of the relief recess creates a relief gap and prevents the first current collecting portion from abutting the cover body, thereby reducing the risk of the first current collecting portion squeezing the weak portion and improving safety. The first current collecting portion supports the central area of ​​the first tab, while the first protrusion supports the edge area of ​​the first tab. This improves the uniformity of the force applied to the first tab and reduces the risk of offset or misalignment of the electrode assembly's pole pieces in the thickness direction.

[0018] In some embodiments, the first current collecting portion is used to abut against and be welded to the first electrode tab, and the second current collecting portion is used to abut against and be welded to the cover body.

[0019] In the above solution, the avoidance recess can reduce the thickness of the first current collecting part, thereby reducing the welding power required for welding the first current collecting part and the first electrode tab, reducing heat generation, and lowering the risk of burning other components.

[0020] In some embodiments, at least a portion of the current collecting member is located between the first protrusion and the first electrode tab. The first protrusion supports the first electrode tab through the current collecting member.

[0021] In the above solution, the first protrusion supports the first tab via the current collecting member, thereby reducing the shaking amplitude of the electrode assembly when the battery cell vibrates and improving the stability of the electrode assembly. At the same time, the first protrusion supports the current collecting member to form an escape gap between the current collecting member and the cover body.

[0022] In some embodiments, a portion of the current collecting member is used to abut against and be welded to the first electrode tab, and another portion of the current collecting member is used to abut against and be welded to the first protrusion.

[0023] In the above solution, welding can reduce the contact resistance between the current collecting member and the end cover and the contact resistance between the current collecting member and the first electrode tab, thereby improving the current carrying capacity.

[0024] In some embodiments, the current collecting member is a flat plate structure.

[0025] In the above solution, the flat-plate current collecting member is easier to form. It can be in full contact with the first electrode tab, thereby increasing the flow area and providing more uniform support for the first electrode tab, reducing the risk of thickness-direction displacement and misalignment of the electrode assembly's pole pieces. The flat-plate current collecting member can also be completely separated from the cover body, ensuring a clearance between the two, reducing the risk of contact between the current collecting member and weak points.

[0026] In some embodiments, the first protrusion surrounds the outer side of the cover body.

[0027] In some embodiments, the cover body surrounds the outer side of the first protrusion.

[0028] In some embodiments, the end cap further includes a second protrusion that surrounds the outer side of the cap body. The second protrusion protrudes from the inner surface of the cap body in a direction facing the electrode assembly, and the top surface of the second protrusion is closer to the first electrode tab than the top surface of the first protrusion, so that the second protrusion abuts the first electrode tab and is used to support the first electrode tab.

[0029] In the above solution, the first protrusion supports the middle area of ​​the first pole ear through the current collecting component, and the second protrusion supports the edge area of ​​the first pole ear. This can improve the uniformity of the force on the first pole ear and reduce the risk of displacement and dislocation of the pole piece of the electrode assembly in the thickness direction.

[0030] In some embodiments, a second recess is formed on the end cover at a position corresponding to the second protrusion, which is recessed from the outer surface of the cover body in a direction facing the electrode assembly, and the bottom surface of the second recess is closer to the first electrode tab than the inner surface of the cover body.

[0031] In the above solution, under the premise of ensuring the protrusion of the second convex portion, the concavity of the second concave portion is further ensured to improve the elasticity of the second convex portion and reduce the risk of the second convex portion crushing the first tab during assembly.

[0032] In some embodiments, the outer side surface of the second protrusion abuts against the inner surface of the shell and is used to be welded to the shell to close the opening.

[0033] In the above solution, welding can achieve sealing, reduce the risk of electrolyte leakage, and improve the connection strength and current carrying capacity between the second protrusion and the housing. The second recess can reduce the strength of the second protrusion and increase its elasticity. In this way, during the welding process of the second protrusion and the housing, the second protrusion can release welding stress through deformation, thereby reducing the risk of deformation and cracking in the weld area and improving sealing performance.

[0034] In some embodiments, the cover body is a flat plate structure.

[0035] In some embodiments, the cover body includes a main plate body and a third protrusion, the main plate body surrounding the outside of the third protrusion, the first protrusion surrounding the outside of the main plate body, and the weak portion formed in the third protrusion. The main plate body includes a first inner surface and a first outer surface disposed opposite each other, the first inner surface facing the electrode assembly, the first protrusion and the third protrusion both protruding from the first inner surface in a direction facing the electrode assembly, and the top surface of the first protrusion is closer to the first electrode tab than the top surface of the third protrusion, thereby forming a clearance gap between the current collecting member and the third protrusion to avoid the weak portion.

[0036] In this solution, the third protrusion provided in the middle of the end cap increases its strength and reduces deformation. The third protrusion is convex and less susceptible to deformation. Therefore, placing the weak point on the third protrusion reduces creep in the weak point, thereby lowering the risk of failure. This solution creates a clearance between the third protrusion and the current collecting member to reduce the risk of the current collecting member blocking the exhaust passage in the event of a rupture of the weak point, thereby ensuring smooth exhaust and minimizing safety risks.

[0037] In some embodiments, a third recessed portion is formed on the cover body at a position corresponding to the third protrusion, which is recessed from the first outer surface in a direction facing the electrode assembly, and the third protrusion forms a weak portion in an area opposite to the bottom surface of the third recessed portion.

[0038] In the above solution, the weak portion is formed in the area of ​​the third convex portion opposite to the bottom surface of the third concave portion, which can increase the distance between the weak portion and other external components and reduce the risk of the weak portion being crushed by external components.

[0039] In some embodiments, the cover body is provided with a groove, and a region of the cover body opposite to the groove forms a weak portion.

[0040] In the above solution, the thickness and strength of the weak portion are reduced by providing the groove, so that the end cover can be broken along the weak portion when the internal pressure of the battery cell reaches a threshold.

[0041] In some embodiments, the end cap electrically connects the first tab and the housing.

[0042] In the above solution, the housing itself can serve as the output terminal of the battery cell. When multiple battery cells are assembled into a group, the housing can be electrically connected to the confluence component, which can not only increase the flow area but also make the structural design of the confluence component more flexible.

[0043] In some embodiments, the housing includes sidewalls and a bottom wall connected to the sidewalls. The sidewalls extend along the thickness of the end cap and surround the periphery of the electrode assembly. The bottom wall is provided with an electrode lead-out hole. The electrode assembly also includes a second tab. The first and second tabs have opposite polarities and are located at opposite ends of the electrode assembly. The battery cell also includes an electrode terminal mounted in the electrode lead-out hole, the electrode terminal being electrically connected to the second tab.

[0044] In the above solution, the bottom wall and electrode terminals can serve as the two output poles of the battery cell, which can simplify the battery cell structure and ensure the battery cell's current carrying capacity. The bottom wall and electrode terminals are located at the same end of the battery cell. Therefore, when multiple battery cells are assembled into a group, the current collecting component can be assembled on the same side of the battery cells, which can simplify the assembly process and improve assembly efficiency.

[0045] In some embodiments, the bottom wall and the side walls are integrally provided. This solution can omit the process of connecting the bottom wall and the side walls.

[0046] In some embodiments, the first electrode tab is a negative electrode tab, and the base material of the shell is steel.

[0047] In the above solution, the housing is electrically connected to the negative electrode tab, meaning the housing is in a low-potential state. The steel housing is less susceptible to corrosion by the electrolyte in this low-potential state, thus reducing safety risks.

[0048] In some embodiments, the base material of the housing and the base material of the end cap are the same. This solution can ensure the welding strength between the housing and the end cap and ensure the sealing of the battery cell.

[0049] In some embodiments, the battery cells are cylindrical battery cells.

[0050] In a second aspect, an embodiment of the present application provides a battery comprising a plurality of battery cells according to any one of the embodiments of the first aspect.

[0051] In a third aspect, an embodiment of the present application provides an electrical device comprising the battery of the second aspect, the battery being used to provide electrical energy.

[0052] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a battery cell, comprising:

[0053] providing a housing having an opening;

[0054] Providing an electrode assembly and installing the electrode assembly into the housing, wherein the electrode assembly is provided with a first electrode tab at one end facing the opening;

[0055] Providing an end cover, the end cover includes a cover body and a first protrusion connected to the cover body, and the cover body is provided with a weak portion;

[0056] Connecting the end cap to the housing so that the end cap covers the opening;

[0057] In which, the end cover is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; the first protrusion protrudes from the cover body in the direction facing the electrode assembly and is used to support the first electrode tab so that an avoidance gap is formed between the first electrode tab and the cover body to avoid the weak portion.

[0058] In a fifth aspect, an embodiment of the present application provides a battery cell manufacturing system, comprising:

[0059] A first providing device is used to provide a housing having an opening;

[0060] A second providing device is used to provide an electrode assembly and install the electrode assembly into the housing, wherein the electrode assembly is provided with a first electrode tab at one end facing the opening;

[0061] A third providing device is used to provide an end cover, the end cover comprising a cover body and a first protrusion connected to the cover body, the cover body being provided with a weak portion;

[0062] An assembly device for connecting the end cover to the housing so that the end cover covers the opening;

[0063] In which, the end cover is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; the first protrusion protrudes from the cover body in the direction facing the electrode assembly and is used to support the first electrode tab so that an avoidance gap is formed between the first electrode tab and the cover body to avoid the weak portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] 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 of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0065] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0066] Figure 2 An exploded schematic diagram of a battery provided in some embodiments of the present application;

[0067] Figure 3 for Figure 2 An exploded schematic diagram of the battery module shown;

[0068] Figure 4 Schematic diagram of an explosion of a battery cell provided in some embodiments of the present application;

[0069] Figure 5 A schematic cross-sectional view of a battery cell provided in some embodiments of the present application;

[0070] Figure 6 for Figure 5 An enlarged schematic diagram of a battery cell at circle A is shown;

[0071] Figure 7 Schematic cross-sectional views of battery cells provided in other embodiments of the present application;

[0072] Figure 8 for Figure 7 An enlarged schematic diagram of a battery cell shown at circle B;

[0073] Figure 9 Schematic cross-sectional views of battery cells provided in some other embodiments of the present application;

[0074] Figure 10 for Figure 9 An enlarged schematic diagram of a battery cell shown at box C;

[0075] Figure 11 A schematic flow chart of a method for manufacturing a battery cell according to some embodiments of the present application;

[0076] Figure 12 A schematic block diagram of a battery cell manufacturing system provided in some embodiments of the present application.

[0077] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] The term "plurality" used in this application refers to two or more (including two).

[0085] In this application, battery cells may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, and the embodiments of this application are not limited thereto. Battery cells may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of this application are not limited thereto.

[0086] 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 casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0087] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell primarily relies on the movement of metal ions between the positive and negative electrode sheets to operate. 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 current collector. The positive current collector includes a positive coating area and a positive electrode tab connected to the positive coating area. The positive coating area is coated with the positive active material layer, while the positive electrode tab is not coated with the positive active material layer. Taking lithium-ion batteries as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes a positive active material. The positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, which is coated on the surface of the current collector. The negative electrode current collector includes a negative electrode coating region and a negative electrode tab connected to the negative electrode coating region. The negative electrode coating region is coated with the negative electrode active material layer, while the negative electrode tab is not coated with the negative electrode active material layer. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes a negative electrode active material, which can be carbon or silicon. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene).

[0088] The battery cell further includes a housing and an end cap. The housing has an opening and is used to accommodate the electrode assembly. The electrode assembly can be assembled into the housing through the opening of the housing. The end cap is used to cover the opening of the housing to achieve sealing.

[0089] For battery cells, the main safety hazards come from the charging and discharging process, as well as the appropriate ambient temperature design. In order to effectively avoid unnecessary losses, there are generally at least three protection measures for battery cells. Specifically, the protection measures include at least switching elements, selection of appropriate separator materials and pressure relief mechanisms. The switching element refers to an element that can stop the battery from charging or discharging when the temperature or resistance inside the battery cell reaches a certain threshold. The separator is used to isolate the positive and negative pole pieces. When the temperature rises to a certain value, it can automatically dissolve the micron-level (or even nano-level) micropores attached to it, so that metal ions cannot pass through the separator, terminating the internal reaction of the battery cell.

[0090] A pressure relief mechanism is a component or part that activates to release internal pressure when the internal pressure of a battery cell reaches a predetermined threshold. This threshold varies depending on the design requirements. It may be determined by the materials of one or more of the positive and negative electrode plates, electrolyte, and separator in the battery cell.

[0091] The "activation" mentioned in this application refers to the action of the pressure relief mechanism or its activation to a certain state, so that the internal pressure of the battery cell can be released. The action produced by the pressure relief mechanism may include but is not limited to: at least a part of the pressure relief mechanism is broken, shattered, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances inside the battery cell will be discharged outward from the actuated part as emissions. In this way, the battery cell can be depressurized under controllable pressure, thereby avoiding potential more serious accidents. The emissions from the battery cell mentioned in this application include but are not limited to: electrolyte, dissolved or split positive and negative pole pieces, fragments of separators, high-temperature and high-pressure gases produced by the reaction, flames, etc.

[0092] The pressure relief mechanism on a battery cell has a significant impact on its safety. For example, short circuits, overcharging, and other events can cause thermal runaway within the cell, leading to a sudden increase in pressure. In these situations, the pressure relief mechanism activates to release the internal pressure, preventing explosion or fire.

[0093] The pressure relief mechanism may be in the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, and may specifically be a pressure-sensitive element or structure, that is, when the internal pressure of the battery cell reaches a predetermined threshold, the pressure relief mechanism executes an action or a weak structure provided in the pressure relief mechanism ruptures, thereby forming an opening or channel for the internal pressure to be released.

[0094] To simplify the battery cell structure, the inventors attempted to integrate a pressure relief mechanism into the end cap. For example, the inventors designed a weak portion in the end cap, which is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold, releasing the internal pressure. When a short circuit or overcharge occurs, thermal runaway can occur within the battery cell, causing a sudden pressure increase. In this case, the rupture of the weak portion releases the internal pressure outward, preventing the battery cell from exploding or catching fire, thereby improving safety.

[0095] However, after research, the inventors found that when the battery cell vibrates, the tabs of the electrode assembly are easily squeezed and impacted by the weak parts. Since the weak parts have low strength, when squeezed and impacted by the tabs, the weak parts may rupture before the internal pressure of the battery cell reaches the threshold, causing the battery cell to fail and triggering safety problems.

[0096] In view of this, an embodiment of the present application provides a technical solution in which an end cap includes a cap body and a first protrusion connected to the cap body. The cap body is provided with a weakened portion. The first protrusion protrudes from the cap body in a direction facing the electrode assembly and is used to support the electrode assembly's tab, thereby forming a clearance between the tab and the cap body to avoid the weakened portion. Battery cells with this structure can reduce the risk of the electrode assembly squeezing the weakened portion, thereby improving the safety of the battery cells.

[0097] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0098] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0099] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0100] Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of the present application. Figure 1 As shown, a battery 2 is provided inside the vehicle 1, and the battery 2 can be provided at the bottom, head, or tail of the vehicle 1. The battery 2 can be used to power the vehicle 1, for example, the battery 2 can be used as an operating power source for the vehicle 1.

[0101] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0102] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0103] Figure 2 Schematic diagram of the explosion of the battery provided in some embodiments of the present application. Figure 2 As shown, the battery 2 includes a box 5 and a battery cell ( Figure 2The battery cells are housed in the box body 5 .

[0104] The housing 5 is used to house battery cells and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other, and the first housing portion 5a and the second housing portion 5b together define a storage space 5c for accommodating the battery cells. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0105] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0106] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box body.

[0107] In battery 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within housing 5.

[0108] Figure 3 for Figure 2 An exploded diagram of the battery module is shown.

[0109] In some embodiments, as Figure 3 As shown, there are multiple battery cells 7, which are first connected in series, in parallel, or in mixed series to form a battery module 6. The multiple battery modules 6 are then connected in series, in parallel, or in mixed series to form a whole, which is accommodated in a box.

[0110] The multiple battery cells 7 in the battery module 6 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 7 in the battery module 6 .

[0111] Figure 4 Schematic diagram of an explosion of a battery cell provided in some embodiments of the present application; Figure 5 A schematic cross-sectional view of a battery cell provided in some embodiments of the present application; Figure 6 for Figure 5 An enlarged schematic diagram of a battery cell at circle A is shown.

[0112] like Figures 4 to 6 As shown, the battery cell 7 of the present embodiment includes: a housing 20 having an opening 21; an electrode assembly 10 housed within the housing 20, with a first tab 12 provided at one end of the electrode assembly 10 facing the opening 21; and an end cap 30 for covering the opening 21. The end cap 30 includes a cover body 31 and a first protrusion 32 connected to the cover body 31. The cover body 31 is provided with a weakened portion 311. The end cap 30 is configured to rupture along the weakened portion 311 to release the internal pressure of the battery cell 7 when the internal pressure reaches a threshold. The first protrusion 32 protrudes from the cover body 31 in a direction facing the electrode assembly 10 and supports the first tab 12, thereby forming a clearance gap G between the first tab 12 and the cover body 31 to avoid the weakened portion 311.

[0113] The electrode assembly 10 includes a first electrode plate, a second electrode plate, and a separator, wherein the separator is used to separate the first electrode plate and the second electrode plate. The polarity of the first electrode plate and the second electrode plate are opposite. In other words, one of the first electrode plate and the second electrode plate is a positive electrode plate, and the other of the first electrode plate and the second electrode plate is a negative electrode plate.

[0114] Optionally, the first pole piece, the second pole piece and the separator are all strip-shaped structures, and the first pole piece, the second pole piece and the separator are wound together to form a wound structure. The wound structure can be a cylindrical structure, a flat structure or a structure of other shapes.

[0115] The electrode assembly 10 includes a main body 11, a first electrode tab 12, and a second electrode tab 13. The first electrode tab 12 and the second electrode tab 13 protrude from the main body 11. The first electrode tab 12 is the portion of the first electrode sheet not coated with the active material layer, and the second electrode tab 13 is the portion of the second electrode sheet not coated with the active material layer. Accordingly, one of the first electrode tab 12 and the second electrode tab 13 is a positive polarity tab, and the other is a negative polarity tab.

[0116] The first electrode tab 12 and the second electrode tab 13 may extend from the same side of the main body 11 , or may extend from opposite sides thereof.

[0117] Exemplarily, the first electrode tab 12 and the second electrode tab 13 are respectively provided on both sides of the main body 11. In other words, the first electrode tab 12 and the second electrode tab 13 are respectively provided at both ends of the electrode assembly 10. Optionally, the first electrode tab 12 is located at the end of the electrode assembly 10 facing the end cap 30, and the second electrode tab 13 is located at the end of the electrode assembly 10 facing away from the end cap 30.

[0118] Optionally, the first pole tab 12 is wound around the central axis X of the electrode assembly 10 in multiple turns. In other words, the first pole tab 12 includes multiple turns of pole tab layers. After the winding is completed, the first pole tab 12 is generally cylindrical, and a gap is left between two adjacent turns of pole tab layers. In the embodiment of the present application, the first pole tab 12 can be processed to reduce the gap between the pole tab layers to facilitate the connection of the first pole tab 12 with other conductive structures. For example, in the embodiment of the present application, the first pole tab 12 can be flattened to make the end area of ​​the first pole tab 12 away from the main body 11 gather and gather together; the flattening process forms a dense end face at the end of the first pole tab 12 away from the main body 11, reducing the gap between the pole tab layers, and facilitating the connection of the first pole tab 12 with other conductive structures. Alternatively, in the embodiment of the present application, conductive material can also be filled between two adjacent turns of pole tab layers to reduce the gap between the pole tab layers.

[0119] Optionally, the second electrode tab 13 is wound multiple times around the central axis X of the electrode assembly 10, and the second electrode tab 13 includes multiple electrode tab layers. Exemplarily, the second electrode tab 13 is also flattened to reduce gaps between the electrode tab layers of the second electrode tab 13.

[0120] The shell 20 is a hollow structure with one side open. The end cover 30 covers the opening 21 of the shell 20 and forms a sealed connection to form a receiving cavity for accommodating the electrode assembly 10 and the electrolyte.

[0121] The housing 20 is a hollow structure, forming a space within it for accommodating the electrode assembly 10. The housing 20 can have various shapes, such as a cylinder or a rectangular parallelepiped. The shape of the housing 20 can be determined based on the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, a cylindrical housing can be used; if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped housing can be used.

[0122] The housing 20 includes a sidewall 22 and a bottom wall 23. The sidewall 22 surrounds the outside of the electrode assembly 10, and the bottom wall 23 is connected to one end of the sidewall 22. The sidewall 22 has a cylindrical structure, for example, a circular cylinder or a square cylinder; the bottom wall 23 has a plate-like structure, and its shape corresponds to the shape of the sidewall 22. Optionally, one end of the sidewall 22 forms an opening 21, and the bottom wall 23 is connected to the end of the sidewall 22 facing away from the opening 21.

[0123] The sidewall 22 and the bottom wall 23 can be an integrally formed structure, that is, the housing 20 is an integrally formed component. Of course, the sidewall 22 and the bottom wall 23 can also be two components provided separately, and then connected together by welding, riveting, bonding, etc.

[0124] The end cap 30 can be electrically connected to the electrode assembly 10 or insulated from the electrode assembly 10. Optionally, the end cap 30 is electrically connected to the first electrode tab 12. Of course, the end cap 30 can be directly electrically connected to the first electrode tab 12 or electrically connected to the first electrode tab 12 through other conductive components.

[0125] The shell 20 can be positively charged, negatively charged, or uncharged. When the shell 20 needs to be charged, the shell 20 can be directly connected to the tab of the electrode assembly 10 or electrically connected to the tab through other conductive components.

[0126] The end cap 30 and the housing 20 can be connected by welding, so that the end cap 30 and the housing 20 have the same polarity. For example, when the housing 20 needs to be positively charged, the end cap 30 can be used to electrically connect the housing 20 to the positive polarity tab; when the housing 20 needs to be negatively charged, the end cap 30 can be used to electrically connect the housing 20 to the negative polarity tab. Of course, the housing 20 can also be connected to the tab via other conductive structures, and this embodiment is not limited to this.

[0127] The housing 20 and the end cover 30 may be made of the same material or different materials.

[0128] The cover body 31 is a plate-like structure having an inner surface and an outer surface disposed opposite each other along the thickness direction Z of the end cap 30. The inner surface 31a of the cover body faces the electrode assembly 10. The inner surface 31a of the cover body can be a flat surface, a curved surface, or a combination of a flat surface and a curved surface. The outer surface 31b of the cover body can be a flat surface, a curved surface, or a combination of a flat surface and a curved surface. Optionally, the inner surface 31a of the cover body and the outer surface 31b of the cover body are both flat and parallel.

[0129] The weak portion 311 is a part of the cover body 31, and its strength is lower than other parts of the cover body 31. In this embodiment, the strength of the weak portion 311 can be reduced by reducing its thickness, changing its material, or other methods.

[0130] The weak portion 311 may surround the central axis X of the electrode assembly 10 once, or may only surround the central axis by 1 / 2, 2 / 3, or 3 / 4, etc., which is not limited in this embodiment.

[0131] The first protrusion 32 protrudes relative to the inner surface 31a of the cover body in a direction facing the electrode assembly 10, so that at least a portion of the first protrusion 32 protrudes from the inner surface 31a of the cover body. This embodiment does not limit the extent to which the first protrusion 32 protrudes from the inner surface 31a of the cover body.

[0132] There may be one or more first protrusions 32 . Optionally, when there are more than one first protrusions 32 , the first protrusions 32 may be spaced apart along the circumference of the end cover 30 .

[0133] The first protrusion 32 may abut against the first electrode tab 12 to directly support the first electrode tab 12 ; of course, the first protrusion 32 may also indirectly support the first electrode tab 12 by supporting other components.

[0134] In the thickness direction Z, the clearance gap G is located between the first electrode tab 12 and the cover body 31. The clearance gap G is the space between the first electrode tab 12 and the cover body 31 that is not filled by other solid components. The clearance gap G is opposite to the weak portion 311 along the thickness direction Z, thereby providing a clearance for the weak portion 311.

[0135] Other components may be disposed between the first electrode tab 12 and the cover body 31 as long as the gap G can avoid the component and the weak portion 311. Of course, no other components may be disposed between the first electrode tab 12 and the cover body 31.

[0136] In this embodiment, the first protrusion 32 protruding from the cover body 31 can support the first electrode tab 12 to reduce the amplitude of shaking of the electrode assembly 10 when the battery cell 7 vibrates, thereby improving the stability of the electrode assembly 10. The first protrusion 32 supports the first electrode tab 12, forming an escape gap G between the first electrode tab 12 and the cover body 31 for circumventing the weak portion 311. This reduces the risk of the electrode assembly 10 squeezing the weak portion 311, reduces the possibility of failure of the weak portion 311, and improves the safety of the battery cell 7.

[0137] In particular, for the first tab 12 with a wound structure, the end surface facing away from the main body 11 has poor flatness. If the end surface of the first tab 12 squeezes the weak portion 311, the weak portion 311 is more likely to break. The present application provides an escape gap G to reduce the risk of the first tab 12 squeezing the weak portion 311, thereby reducing the possibility of failure of the weak portion 311.

[0138] In some embodiments, the cover body 31 is provided with a groove 312 , and a region of the cover body 31 opposite to the groove 312 forms a weak portion 311 .

[0139] Alternatively, the groove 312 may be provided on the inner surface 31a of the cover body, and the weak portion 311 may be the portion of the cover body 31 located between the bottom surface of the groove 312 and the outer surface 31b of the cover body. Alternatively, the groove 312 may also be provided on the outer surface 31b of the cover body, and the weak portion 311 may be the portion of the cover body 31 located between the bottom surface of the groove 312 and the inner surface 31a of the cover body.

[0140] In this embodiment, the groove 312 is provided to reduce the thickness and strength of the weak portion 311 , so that the end cover 30 can be broken along the weak portion 311 when the internal pressure of the battery cell 7 reaches a threshold.

[0141] In some embodiments, the groove 312 can be provided on the inner surface 31 a of the cover body and communicate with the avoidance gap G.

[0142] The groove 312 of this embodiment can further increase the distance between the weak portion 311 and the first electrode tab 12 , thereby reducing the risk of the first electrode tab 12 squeezing the weak portion 311 .

[0143] In some embodiments, the first tab 12 is electrically connected to the end cap 30 .

[0144] The end cap 30 may be directly connected to the first electrode tab 12 . For example, the end cap 30 may be directly welded to the first electrode tab 12 to achieve electrical connection between the end cap 30 and the first electrode tab 12 .

[0145] Alternatively, the end cap 30 may be indirectly connected to the first electrode tab 12 via other conductive structures (eg, current collecting components described below). In this embodiment, either the first protrusion 32 or the cap body 31 may be connected to the conductive structure.

[0146] In this embodiment, the end cap 30 can be charged and can serve as the output electrode of the battery cell 7 , thereby eliminating a traditional electrode terminal and simplifying the structure of the battery cell 7 .

[0147] In some embodiments, the end cap 30 electrically connects the first tab 12 and the housing 20 .

[0148] In this embodiment, the housing 20 itself can serve as the output terminal of the battery cell 7. When multiple battery cells 7 are assembled into a group, the housing 20 can be electrically connected to the confluence component, which can not only increase the flow area but also make the structural design of the confluence component more flexible.

[0149] In some embodiments, the housing 20 includes a sidewall 22 and a bottom wall 23 connected to the sidewall 22. The sidewall 22 extends along the thickness direction Z of the end cap 30 and surrounds the periphery of the electrode assembly 10. The bottom wall 23 defines an electrode lead-out hole 231. The electrode assembly 10 also includes a second electrode tab 13. The first electrode tab 12 and the second electrode tab 13 have opposite polarities and are located at opposite ends of the electrode assembly 10. The battery cell 7 also includes an electrode terminal 40 mounted in the electrode lead-out hole 231. The electrode terminal 40 is electrically connected to the second electrode tab 13.

[0150] The second electrode tab 13 may be directly electrically connected to the electrode terminal 40 , or may be indirectly electrically connected to the electrode terminal 40 through other conductive structures.

[0151] The electrode terminal 40 is insulated and disposed on the bottom wall 23 . The electrode terminal 40 and the bottom wall 23 may have different polarities. The electrode terminal 40 and the bottom wall 23 may serve as two output poles of the battery cell 7 , respectively.

[0152] When the first tab 12 is a negative tab and the second tab 13 is a positive tab, the bottom wall 23 is the negative output pole of the battery cell 7, and the electrode terminal 40 is the positive output pole of the battery cell 7. When the first tab 12 is a positive tab and the second tab 13 is a negative tab, the bottom wall 23 is the positive output pole of the battery cell 7, and the electrode terminal 40 is the negative output pole of the battery cell 7.

[0153] The electrode terminal 40 is fixed to the bottom wall 23. The electrode terminal 40 can be fixed as a whole to the outside of the bottom wall 23, or can extend into the interior of the housing 20 through the electrode lead-out hole 231.

[0154] The first electrode tab 12 is located at the end of the electrode assembly 10 facing the end cap 30, so as to facilitate electrical connection between the end cap 30 and the first electrode tab 12. Correspondingly, the second electrode tab 13 is located at the end of the electrode assembly 10 facing the bottom wall 23, so as to facilitate electrical connection between the electrode terminal 40 and the second electrode tab 13. In the embodiment of the present application, the first electrode tab 12 and the second electrode tab 13 are arranged at both ends of the electrode assembly 10, which can reduce the risk of electrical conduction between the first electrode tab 12 and the second electrode tab 13 and increase the flow area of ​​the first electrode tab 12 and the flow area of ​​the second electrode tab 13.

[0155] In this embodiment, the bottom wall 23 and the electrode terminal 40 can serve as the two output poles of the battery cell 7, which can simplify the structure of the battery cell 7 and ensure the current carrying capacity of the battery cell 7. The bottom wall 23 and the electrode terminal 40 are located at the same end of the battery cell 7. Therefore, when multiple battery cells 7 are assembled into a group, the current collecting component can be assembled to the same side of the battery cells 7, which can simplify the assembly process and improve assembly efficiency.

[0156] In some embodiments, the bottom wall 23 and the side wall 22 are integrally formed. This embodiment can omit the process of connecting the bottom wall 23 and the side wall 22. The housing 20 can be formed by a stretching process.

[0157] The electrode lead-out hole 231 in the embodiment of the present application is formed after the shell 20 is stretched.

[0158] The inventors have tried to roll the open end of the shell so that the open end of the shell is folded inward and forms a flange structure. The flange structure presses the end cover to fix the end cover. The inventors installed the electrode terminal on the end cover and used the flange structure and electrode terminal as the two output poles of the battery cell. However, the larger the size of the flange structure, the higher the risk of curling and wrinkling after forming; if the flange structure curls and wrinkles, it will cause the surface of the flange structure to be uneven, and when the flange structure is welded to the collector component, there will be problems with poor welding. Therefore, the size of the flange structure is relatively limited, resulting in insufficient current capacity of the battery cell.

[0159] In this embodiment, an electrode lead-out hole 231 for mounting the electrode terminal 40 is formed on the bottom wall 23 by a perforation process, thereby positioning the positive and negative output electrodes at the end of the battery cell 7 facing away from the outlet 21. The bottom wall 23 is formed during the molding process of the housing 20. The electrode lead-out hole 231 ensures the flatness of the bottom wall 23 and the connection strength between the bottom wall 23 and the current collector. Furthermore, the flatness of the bottom wall 23 is not constrained by its own dimensions, allowing it to be larger, thereby improving the current handling capacity of the battery cell 7.

[0160] In some embodiments, the first electrode tab 12 is a negative electrode tab, and the base material of the shell 20 is steel.

[0161] The housing 20 is electrically connected to the negative electrode tab, that is, the housing 20 is in a low potential state. The steel housing 20 is not easily corroded by the electrolyte in the low potential state, thereby reducing safety risks.

[0162] In some embodiments, the housing 20 is welded to the end cap 30. Welding can not only achieve the connection between the housing 20 and the end cap 30, improve the flow capacity between the housing 20 and the end cap 30, but also ensure the sealing.

[0163] In some embodiments, the base material of the housing 20 is the same as the base material of the end cover 30. Optionally, the base material of the housing 20 and the base material of the end cover 30 are both steel.

[0164] In this embodiment, the base material of the housing 20 and the base material of the end cover 30 are the same, which can ensure the welding strength between the housing 20 and the end cover 30 and the sealing of the battery cell 7.

[0165] In some embodiments, the battery cell 7 is a cylindrical battery cell. Correspondingly, the electrode assembly 10 is a cylindrical structure, and the housing 20 is a cylindrical hollow structure.

[0166] In some embodiments, a first recess 33 is formed on the end cover 30 at a position corresponding to the first protrusion 32, which is recessed from the outer surface 31b of the cover body in a direction facing the electrode assembly 10, and the bottom surface of the first recess 33 is closer to the first electrode tab 12 than the inner surface 31a of the cover body.

[0167] The first recess 33 can reduce the strength of the first protrusion 32 and improve the elasticity of the first protrusion 32. In this way, when the first protrusion 32 extends into the shell 20 and presses against the first tab 12, the first protrusion 32 can release stress through deformation, reduce the impact force, and reduce the risk of the first tab 12 being crushed.

[0168] The first concave portion 33 and the first convex portion 32 can be formed by stamping the end cap 30. The greater the depth of the first concave portion 33 along the thickness direction Z, the greater the extent to which the first convex portion 32 protrudes from the inner surface 31a of the cap body, and the larger the clearance G.

[0169] The embodiment of the present application ensures that the first protrusion 32 protrudes beyond the cover body 31 to more effectively support the first electrode tab 12, increases the size of the clearance gap G along the thickness direction Z, and further reduces the risk of the electrode assembly 10 being squeezed and contacted by the weak portion 311. Furthermore, while ensuring the protrusion of the first protrusion 32, the embodiment of the present application further ensures the recessed degree of the first recess 33, thereby increasing the elasticity of the first protrusion 32 and reducing the risk of the first protrusion 32 crushing the first electrode tab 12 during assembly.

[0170] Optionally, the bottom surface of the first recess 33 is a plane and parallel to the inner surface 31 a of the cover body.

[0171] In some embodiments, the battery cell 7 further includes a current collecting member 50 disposed between the end cap 30 and the first electrode tab 12. The current collecting member 50 is used to connect the end cap 30 and the first electrode tab 12 to achieve electrical connection between the end cap 30 and the first electrode tab 12. In the thickness direction Z of the end cap 30, a clearance gap G is located between the current collecting member 50 and the cover body 31.

[0172] The current collecting member 50 can be connected to the first electrode tab 12 by welding, bonding or other means to achieve electrical connection with the first electrode tab 12. The current collecting member 50 can be connected to the end cap 30 by welding, bonding or other means to achieve electrical connection with the end cap 30.

[0173] The current collecting member 50 may be connected to the first protrusion 32 , may be connected to the cover body 31 , or may be connected to other parts of the end cover 30 .

[0174] The first protrusion 32 protrudes from the cover body 31, so the first protrusion 32 separates the cover body 31 from the first electrode tab 12 in the thickness direction Z. If the end cap 30 and the first electrode tab 12 are directly connected, the first electrode tab 12 can only be connected to the first protrusion 32 of the end cap 30. If the first protrusion 32 and the first electrode tab are directly connected, only the portion of the first electrode tab 12 opposite the first protrusion 32 can be directly connected to the first protrusion 32. As a result, the area of ​​the first electrode tab 12 that can directly transmit current is limited by the first protrusion 32, resulting in insufficient flow area between the first protrusion 32 and the first electrode tab 12. The current in the portion of the first electrode tab 12 opposite the cover body 31 in the thickness direction Z must first flow to the portion of the first electrode tab 12 welded to the first protrusion 32, and then flow to the first protrusion 32. This will cause significant differences in the conductive paths between different areas of the first electrode tab 12 and the end cap 30, affecting the flow capacity and charging efficiency of the battery cell 7.

[0175] In the embodiment of the present application, a current collecting component 50 is provided to connect the first pole tab 12 and the end cover 30, so that the area of ​​the first pole tab 12 that can directly transmit current is no longer restricted by the first protrusion 32. The current of the first pole tab 12 can be collected into the end cover 30 through the current collecting component 50. In this way, the current collecting component 50 can reduce the difference in the conductive path between different areas of the first pole tab 12 and the end cover 30, improve the uniformity of the current density of the first pole sheet, reduce the internal resistance, and improve the current flow capacity and charging efficiency of the battery cell 7.

[0176] In this embodiment, the avoidance gap G is located between the current collecting component 50 and the cover body 31. This can not only reduce the risk of the current collecting component 50 squeezing the weak portion 311, but also reduce the possibility of the current collecting component 50 blocking the exhaust channel when the weak portion 311 ruptures, thereby ensuring smooth exhaust and improving safety.

[0177] In some embodiments, the current collecting member 50 covers the weak portion 311 along the thickness direction Z of the end cover 30 to separate the weak portion 311 from the first electrode tab 12 .

[0178] A portion of the current collecting member 50 is spaced apart from the weak portion 311 along the thickness direction Z and covers the weak portion 311 . A projection of the weak portion 311 along the thickness direction Z is located within a projection of the current collecting member 50 along the thickness direction Z.

[0179] In this embodiment, the current collecting member 50 can separate the weak portion 311 from the first electrode tab 12 to reduce active particles in the electrode assembly 10 falling onto the weak portion 311 and reduce the risk of corrosion of the weak portion 311 .

[0180] In some embodiments, at least a portion of the current collecting member 50 is located between the first protrusion 32 and the first electrode tab 12 . The first protrusion 32 supports the first electrode tab 12 through the current collecting member 50 .

[0181] The first protrusion 32 supports the first electrode tab 12 via the current collecting member 50 to reduce the shaking amplitude of the electrode assembly 10 when the battery cell 7 vibrates, thereby improving the stability of the electrode assembly 10. At the same time, the first protrusion 32 supports the current collecting member 50 to form an escape gap G between the current collecting member 50 and the cover body 31.

[0182] In some embodiments, a portion of the current collecting member 50 is used to abut against and be welded to the first electrode tab 12 , and another portion of the current collecting member 50 is used to abut against and be welded to the first protrusion 32 .

[0183] When assembling the battery cell 7 , the current collecting member 50 is first pressed against and welded to the first electrode tab 12 to form a first welding portion W1 , and then the end cover 30 and the current collecting member 50 are welded to form a second welding portion W2 .

[0184] In this embodiment, two different parts of the current collecting member 50 are welded to the end cover 30 and the first electrode tab 12 respectively to reduce the risk of welding between the first welding portion W1 and the second welding portion W2, thereby ensuring the connection strength between the current collecting member 50 and the first electrode tab 12 and the connection strength between the end cover 30 and the current collecting member 50.

[0185] Welding can reduce the contact resistance between the current collecting member 50 and the end cover 30 and the contact resistance between the current collecting member 50 and the first electrode tab 12 , thereby improving the current carrying capacity.

[0186] In some embodiments, the current collecting member 50 is a flat plate structure.

[0187] The flat-plate current collecting member 50 is easier to form. The flat-plate current collecting member 50 can be in full contact with the first electrode tab 12, thereby increasing the flow area and enabling the current collecting member 50 to more evenly support the first electrode tab 12, reducing the risk of the electrode sheets of the electrode assembly 10 shifting or misaligning in the thickness direction Z. The flat-plate current collecting member 50 can also be completely separated from the cover body 31, ensuring a clearance G between the current collecting member 50 and the cover body 31, reducing the risk of the current collecting member 50 contacting the weak portion 311.

[0188] In some embodiments, the cover body 31 surrounds the outer side of the first protrusion 32. In other words, the cover body 31 is an annular structure surrounding the outer side of the first protrusion 32.

[0189] In some embodiments, the end cap 30 further includes a second protrusion 34 that surrounds the outer side of the cap body 31. The second protrusion 34 protrudes from the inner surface 31a of the cap body in a direction facing the electrode assembly 10, and the top surface of the second protrusion 34 is closer to the first electrode tab 12 than the top surface of the first protrusion 32, so that the second protrusion 34 abuts against the first electrode tab 12 and is used to support the first electrode tab 12.

[0190] The second protrusion 34 is an annular structure surrounding the outer side of the cover body 31. The top surface of the first protrusion 32 abuts the current collecting member 50; optionally, the top surface of the first protrusion 32 is flat. The top surface of the second protrusion 34 abuts the first electrode tab 12; optionally, the top surface of the second protrusion 34 is flat or curved.

[0191] The second protrusion 34 is spaced apart from the current collecting member 50 to prevent the second protrusion 34 from interfering with the contact between the current collecting member 50 and the first protrusion 32, thereby ensuring that the first protrusion 32 is in close contact with the current collecting member 50. Optionally, the second protrusion 34 surrounds the outer side of the current collecting member 50.

[0192] The second protrusion 34 protrudes from the inner surface 31 a of the cover body to a greater extent than the first protrusion 32 , so that the top surface of the second protrusion 34 is closer to the first tab 12 than the top surface of the first protrusion 32 .

[0193] In this embodiment, the first protrusion 32 supports the middle area of ​​the first pole tab 12 through the current collecting component 50, and the second protrusion 34 supports the edge area of ​​the first pole tab 12. This can improve the uniformity of the force applied to the first pole tab 12 and reduce the risk of the pole piece of the electrode assembly 10 being offset or misaligned in the thickness direction Z.

[0194] In some embodiments, a second recess 35 is formed on the end cover 30 at a position corresponding to the second protrusion 34, which is recessed from the outer surface 31b of the cover body in a direction facing the electrode assembly 10, and the bottom surface of the second recess 35 is closer to the first electrode tab 12 than the inner surface 31a of the cover body.

[0195] The second recess 35 can reduce the strength of the second protrusion 34 and improve the elasticity of the second protrusion 34. In this way, when the second protrusion 34 extends into the shell 20 and presses against the first tab 12, the second protrusion 34 can release stress through deformation, reduce the impact force, and reduce the risk of the first tab 12 being crushed.

[0196] The second recess 35 and the second protrusion 34 can be formed by stamping the end cap 30. The greater the depth of the second recess 35 in the thickness direction Z, the greater the extent to which the second protrusion 34 protrudes from the inner surface 31a of the cap body.

[0197] In the embodiment of the present application, the second recess 35 is further ensured to be recessed while ensuring the protrusion of the second protrusion 34 , so as to improve the elasticity of the second protrusion 34 and reduce the risk of the second protrusion 34 crushing the first tab 12 during assembly.

[0198] In some embodiments, the outer side surface 341 of the second protrusion abuts against the inner surface of the housing 20 and is used for welding with the housing 20 to close the opening 21 .

[0199] The outer side surface 341 of the second protrusion is the surface of the second protrusion 34 facing the side wall 22 of the housing 20. The outer side surface 341 of the second protrusion is a cylindrical surface. Optionally, the outer side surface 341 of the second protrusion is a cylindrical surface.

[0200] The portion of the second protrusion 34 extending into the housing 20 may have an interference fit, a transition fit, or a clearance fit with the housing 20. Optionally, the portion of the second protrusion 34 extending into the housing 20 may have an interference fit with the housing 20. The interference fit may increase the connection strength between the housing 20 and the end cover 30 and improve the sealing performance.

[0201] Optionally, the second protrusion 34 and the sidewall 22 of the housing 20 are connected by laser welding. During welding, a laser is irradiated at the junction of the second protrusion 34 and the sidewall 22. The laser melts and connects at least a portion of the outer side surface 341 of the second protrusion and a portion of the inner surface of the housing 20. The outer side surface 341 of the second protrusion abuts the inner surface of the housing 20, which reduces the risk of laser light entering the interior of the housing 20 and burning the electrode assembly 10.

[0202] Alternatively, the laser may be irradiated onto the outer surface of the side wall 22 facing away from the second protrusion 34 .

[0203] In this embodiment, welding can achieve sealing, reduce the risk of electrolyte leakage, and improve the connection strength and flow capacity between the second protrusion 34 and the housing 20.

[0204] The second recess 35 can reduce the strength of the second protrusion 34 and increase its elasticity. Thus, during welding of the second protrusion 34 to the housing 20, the second protrusion 34 can release welding stress through deformation, thereby reducing the risk of deformation and cracking in the weld area and improving sealing performance. While maintaining the protrusion of the second protrusion 34, this embodiment further ensures the degree of depression of the second recess 35 to increase the elasticity of the second protrusion 34, allowing the second protrusion 34 to release welding stress through deformation.

[0205] In some embodiments, the cover body 31 is a flat plate structure, wherein the inner surface 31a and the outer surface 31b of the cover body are both plane and parallel.

[0206] Figure 7Schematic cross-sectional views of battery cells provided in other embodiments of the present application; Figure 8 for Figure 7 An enlarged schematic diagram of a battery cell at circle B is shown.

[0207] like Figure 7 and Figure 8 As shown, in some embodiments, the first protrusion 32 surrounds the outside of the cover body 31. In other words, the first protrusion 32 is an annular structure surrounding the outside of the cover body 31.

[0208] In some embodiments, the portion of the first protrusion 32 extending into the housing 20 may have an interference fit, a transition fit, or a clearance fit with the housing 20. Alternatively, the portion of the first protrusion 32 extending into the housing 20 may have an interference fit with the housing 20. The interference fit may increase the connection strength between the housing 20 and the end cap 30 and improve the sealing performance.

[0209] In some embodiments, the outer side surface of the first protrusion 32 abuts against the inner surface of the housing 20 and is used to be welded to the housing 20 to close the opening 21 .

[0210] In other embodiments, the end cap 30 further includes an extension portion 36 surrounding the outer side of the first protrusion 32 . The surface of the extension portion 36 facing the first tab 12 abuts against and is welded to the end surface of the housing 20 surrounding the opening 21 to close the opening 21 .

[0211] The extension portion 36 includes an inner surface and an outer surface disposed opposite to each other along the thickness direction Z. The inner surface of the extension portion 36 faces the first electrode tab 12. Optionally, the extension portion 36 is an annular plate structure, and both the inner surface and the outer surface of the extension portion 36 are plane.

[0212] The extension portion 36 and the housing 20 are arranged along the thickness direction Z, and the inner surface of the extension portion 36 may be disposed parallel to the end surface of the housing 20 .

[0213] Optionally, during welding, the laser is irradiated at the junction of the end face of the shell 20 and the inner surface of the extension portion 36; after welding, at least part of the inner surface of the extension portion 36 and at least part of the end face of the shell 20 are melted and connected together.

[0214] In this embodiment, when assembling the end cap 30 and the shell 20, the end surface of the shell 20 can play the role of upper limit in the thickness direction Z, reducing the risk of over-insertion of the end cap 30 into the shell 20 and improving assembly efficiency.

[0215] The cover body 31 may be flat as a whole or partially convex.

[0216] In some embodiments, the cover body 31 includes a main plate body 313 and a third protrusion 314. The main plate body 313 surrounds the outside of the third protrusion 314, and the first protrusion 32 surrounds the outside of the main plate body 313. The weak portion 311 is formed in the third protrusion 314. The main plate body 313 includes a first inner surface 313a and a first outer surface 313b that are oppositely disposed. The first inner surface 313a faces the electrode assembly 10. The first protrusion 32 and the third protrusion 314 both protrude from the first inner surface 313a in a direction facing the electrode assembly 10. The top surface of the first protrusion 32 is closer to the first electrode tab 12 than the top surface of the third protrusion 314, thereby forming an escape gap G between the current collecting member 50 and the third protrusion 314 for circumventing the weak portion 311.

[0217] The main plate body 313 is a plate-like structure, with the first inner surface 313a and the first outer surface 313b disposed opposite each other along the thickness direction Z. Optionally, the main plate body 313 is a flat plate structure, with the first inner surface 313a and the first outer surface 313b both being plane and parallel.

[0218] Optionally, the top surface of the first protrusion 32 and the top surface of the third protrusion 314 are both plane and arranged in parallel.

[0219] The inner surface of the cover body includes a first inner surface 313a, a top surface of the third protrusion 314, and a side surface of the third protrusion 314, wherein the side surface of the third protrusion 314 connects the first inner surface 313a and the top surface of the third protrusion 314. At least a portion of the first protrusion 32 protrudes from the top surface of the third protrusion 314 in a direction facing the electrode assembly 10.

[0220] The battery cell 7 may release a small amount of gas during normal circulation, which will increase the internal pressure of the battery cell 7, thereby causing the risk of deformation of the end cover 30; when the end cover 30 is deformed, the weak portion 311 is prone to creep, causing the weak portion 311 to rupture when the internal pressure of the battery cell 7 does not reach the threshold, causing the battery cell 7 to fail.

[0221] This embodiment provides a third protrusion 314 in the middle of the end cap 30 to increase the strength of the end cap 30 and reduce deformation of the end cap 30. The third protrusion 314 is convex and not easily deformed. Therefore, arranging the weak portion 311 on the third protrusion 314 can reduce creep of the weak portion 311, thereby reducing the risk of failure of the weak portion 311.

[0222] In this embodiment, an escape gap G is formed between the third protrusion 314 and the current collecting member 50 to reduce the risk of the current collecting member 50 blocking the exhaust channel when the weak portion 311 is broken, thereby ensuring smooth exhaust and reducing safety risks.

[0223] In some embodiments, a third recess 315 is formed on the cover body 31 at a position corresponding to the third protrusion 314, which is recessed from the first outer surface 313b in a direction facing the electrode assembly 10, and the third protrusion 314 forms a weak portion 311 in an area opposite to the bottom surface of the third recess 315.

[0224] A weak portion 311 is provided on the portion of the third convex portion 314 between the bottom surface of the third concave portion 315 and the top surface of the third convex portion 314. Optionally, the bottom surface of the third concave portion 315 and the top surface of the third convex portion 314 are both plane and parallel.

[0225] The weak portion 311 is formed in an area of ​​the third convex portion 314 opposite to the bottom surface of the third concave portion 315 , which can increase the distance between the weak portion 311 and other external components and reduce the risk of the weak portion 311 being crushed by external components.

[0226] Figure 9 Schematic cross-sectional views of battery cells provided in some other embodiments of the present application; Figure 10 for Figure 9 An enlarged schematic diagram of a battery cell at box C is shown.

[0227] like Figure 9 and Figure 10 As shown, in some embodiments, the first protrusion 32 surrounds the outer side of the cover body 31 , and the current collecting member 50 is used to connect the cover body 31 and the first electrode tab 12 to achieve electrical connection between the end cover 30 and the first electrode tab 12 .

[0228] In some embodiments, the current collecting member 50 includes a first current collecting portion 51 and a second current collecting portion 52 connected to the first current collecting portion 51. The first current collecting portion 51 is used to connect to the first electrode tab 12 to electrically connect the current collecting member 50 and the first electrode tab 12, and the second current collecting portion 52 is used to connect to the cover body 31 to electrically connect the current collecting member 50 and the end cap 30. The first current collecting portion 51 is provided protruding from the surface of the second current collecting portion 52 facing the electrode assembly 10. A relief recess 53 is formed at a position of the current collecting member 50 corresponding to the first current collecting portion 51. The relief recess 53 is recessed from the surface of the second current collecting portion 52 facing away from the electrode assembly 10 in a direction facing the electrode assembly 10, thereby forming a relief gap G between the current collecting member 50 and the cover body 31.

[0229] In this embodiment, the avoidance recess 53 is provided to form an avoidance gap G and prevent the first collecting portion 51 from abutting against the cover body 31 , thereby reducing the risk of the first collecting portion 51 squeezing the weak portion 311 and improving safety.

[0230] The first current collecting portion 51 supports the middle area of ​​the first pole tab 12, and the first protrusion 32 supports the edge area of ​​the first pole tab 12. This can improve the uniformity of the force applied to the first pole tab 12 and reduce the risk of the pole piece of the electrode assembly 10 being offset or misaligned in the thickness direction Z.

[0231] In some embodiments, the first current collecting portion 51 is used to abut against and be welded to the first electrode tab 12 , and the second current collecting portion 52 is used to abut against and be welded to the cover body 31 .

[0232] The avoidance recess 53 can reduce the thickness of the first current collecting portion 51 , thereby reducing the welding power required for welding the first current collecting portion 51 to the first electrode tab 12 , reducing heat generation, and lowering the risk of burning other components (such as separators).

[0233] In some embodiments, the second current collecting portion 52 is a flat plate structure surrounding the outer side of the first current collecting portion 51 .

[0234] The cover body 31 may be flat as a whole or partially convex.

[0235] In some embodiments, the cover body 31 includes a main plate body 313 and a third protrusion 314. The main plate body 313 surrounds the outside of the third protrusion 314, and the first protrusion 32 surrounds the outside of the main plate body 313. The weak portion 311 is formed in the third protrusion 314. The main plate body 313 includes a first inner surface 313a and a first outer surface 313b that are oppositely disposed. The first inner surface 313a faces the electrode assembly 10. The first protrusion 32 and the third protrusion 314 both protrude from the first inner surface 313a in a direction facing the electrode assembly 10. The top surface of the first protrusion 32 is closer to the first electrode tab 12 than the top surface of the third protrusion 314, thereby forming an escape gap G between the current collecting member 50 and the third protrusion 314 for circumventing the weak portion 311.

[0236] The avoidance recess 53 may provide a protruding space for the third protrusion 314 . For example, at least a portion of the third protrusion 314 extends into the avoidance recess 53 .

[0237] In some embodiments, the first protrusion 32 is configured to abut against and be welded to the first electrode tab 12 to achieve electrical connection between the end cap 30 and the first electrode tab 12 .

[0238] In this embodiment, the end cover 30 can be directly electrically connected to the first electrode tab 12 via the first protrusion 32 , thereby simplifying the structure of the battery cell 7 . For example, the current collecting member 50 can be omitted.

[0239] Figure 11 A schematic flow chart of a method for manufacturing a battery cell provided in some embodiments of the present application.

[0240] like Figure 11As shown, the manufacturing method of the battery cell of the embodiment of the present application includes:

[0241] S100, providing a housing, wherein the housing has an opening;

[0242] S200, providing an electrode assembly and installing the electrode assembly into a housing, wherein the electrode assembly is provided with a first electrode tab at one end facing the opening;

[0243] S300, providing an end cover, the end cover comprising a cover body and a first protrusion connected to the cover body, the cover body being provided with a weak portion;

[0244] S400, connecting the end cover to the housing so that the end cover covers the opening;

[0245] In which, the end cover is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; the first protrusion protrudes from the cover body in the direction facing the electrode assembly and is used to support the first electrode tab so that an avoidance gap is formed between the first electrode tab and the cover body to avoid the weak portion.

[0246] It should be noted that the relevant structure of the battery cell manufactured by the above-mentioned method for manufacturing the battery cell can refer to the battery cells provided in the above-mentioned embodiments.

[0247] When assembling a battery cell based on the above-mentioned battery cell manufacturing method, it is not necessary to follow the above-mentioned steps in sequence. In other words, the steps can be performed in the order mentioned in the embodiment, or in a different order than the order mentioned in the embodiment, or several steps can be performed simultaneously. For example, steps S100 and S300 can be performed in any order and can be performed simultaneously.

[0248] Figure 12 A schematic block diagram of a battery cell manufacturing system provided in some embodiments of the present application.

[0249] like Figure 12 As shown, the embodiment of the present application further provides a battery cell manufacturing system 90 including:

[0250] A first providing device 91 is used to provide a housing having an opening;

[0251] A second providing device 92 is used to provide an electrode assembly and install the electrode assembly into the housing, wherein the electrode assembly is provided with a first electrode tab at one end facing the opening;

[0252] A third providing device 93 is used to provide an end cap, the end cap comprising a cap body and a first protrusion connected to the cap body, the cap body being provided with a weak portion;

[0253] Assembling means 94 for connecting the end cap to the housing so that the end cap covers the opening;

[0254] In which, the end cover is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; the first protrusion protrudes from the cover body in the direction facing the electrode assembly and is used to support the first electrode tab so that an avoidance gap is formed between the first electrode tab and the cover body to avoid the weak portion.

[0255] The relevant structure of the battery cells manufactured by the above manufacturing system can refer to the battery cells provided in the above embodiments.

[0256] 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.

[0257] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, comprising: A shell having an opening, the shell comprising a side wall and a bottom wall connected to the side wall, the bottom wall being provided with an electrode lead-out hole; an electrode assembly housed in the housing, the electrode assembly being provided with a first electrode tab at one end facing the opening, and a second electrode tab having a polarity opposite to that of the first electrode tab at one end facing away from the opening; as well as an end cover for covering the opening, the end cover comprising a cover body and a first protrusion connected to the cover body, the cover body being provided with a weakened portion, the end cover being configured to rupture along the weakened portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; an electrode terminal, mounted in the electrode lead-out hole; The first protrusion protrudes from the cover body in a direction facing the electrode assembly and is used to support the first electrode tab, so that a clearance gap for avoiding the weak portion is formed between the first electrode tab and the cover body; The side wall extends along the thickness direction of the end cover and is arranged around the periphery of the electrode assembly. The end cover is electrically connected to the first electrode tab and the shell. The electrode terminal is electrically connected to the second electrode tab. The electrode terminal and the bottom wall serve as two output poles of the battery cell respectively.

2. The battery cell according to claim 1, wherein: A first recessed portion is formed on the end cover at a position corresponding to the first protrusion and is recessed from the outer surface of the cover body in a direction facing the electrode assembly. The bottom surface of the first recessed portion is closer to the first tab than the inner surface of the cover body.

3. The battery cell according to claim 1 or 2, wherein: The first protrusion is used to abut against and weld the first electrode tab to achieve electrical connection between the end cover and the first electrode tab.

4. The battery cell according to claim 1 or 2, further comprising a current collecting member disposed between the end cover and the first tab; The current collecting member is used to connect the end cover and the first electrode tab to achieve electrical connection between the end cover and the first electrode tab; In a thickness direction of the end cover, the escape gap is located between the current collecting member and the cover body.

5. The battery cell according to claim 4, wherein: The current collecting member covers the weak portion along a thickness direction of the end cover to separate the weak portion from the first electrode tab. The battery cell according to claim 4 , wherein: The first protrusion surrounds the outer side of the cover body, and the current collecting component is used to connect the cover body and the first electrode tab to achieve electrical connection between the end cover and the first electrode tab.

7. The battery cell according to claim 6, wherein: The current collecting member includes a first current collecting portion and a second current collecting portion connected to the first current collecting portion, wherein the first current collecting portion is used to connect the first electrode tab to electrically connect the current collecting member and the first electrode tab, and the second current collecting portion is used to connect the cover body to electrically connect the current collecting member and the end cover; The first current collecting portion is protruding from the surface of the second current collecting portion facing the electrode assembly, and an avoidance recess is formed at a position of the current collecting component corresponding to the first current collecting portion, which is recessed from the surface of the second current collecting portion away from the electrode assembly in a direction facing the electrode assembly, so as to form the avoidance gap between the current collecting component and the cover body.

8. The battery cell according to claim 7, wherein: The first current collecting portion is used to abut against and be welded to the first electrode tab, and the second current collecting portion is used to abut against and be welded to the cover body.

9. The battery cell according to claim 4, wherein: At least a portion of the current collecting member is located between the first protrusion and the first electrode tab; The first protrusion supports the first electrode tab via the current collecting member.

10. The battery cell according to claim 9, wherein: A portion of the current collecting member is used to abut against and be welded to the first electrode tab, and another portion of the current collecting member is used to abut against and be welded to the first protrusion.

11. The battery cell according to claim 10, wherein: The current collecting component is a flat plate structure.

12. The battery cell according to claim 9, wherein: The first protrusion surrounds the outer side of the cover body.

13. The battery cell according to claim 9, wherein: The cover body surrounds the outer side of the first protrusion.

14. The battery cell according to claim 13, wherein: The end cap further includes a second protrusion, which surrounds the outer side of the cap body; The second protrusion protrudes from the inner surface of the cover body in a direction facing the electrode assembly, and the top surface of the second protrusion is closer to the first electrode tab than the top surface of the first protrusion, so that the second protrusion abuts against the first electrode tab and is used to support the first electrode tab.

15. The battery cell according to claim 14, wherein: A second recessed portion is formed on the end cover at a position corresponding to the second protrusion, which is recessed from the outer surface of the cover body in a direction facing the electrode assembly. The bottom surface of the second recessed portion is closer to the first tab than the inner surface of the cover body.

16. The battery cell according to claim 14, wherein: The outer side surface of the second protrusion abuts against the inner surface of the shell and is used for welding with the shell to close the opening.

17. The battery cell according to claim 6, wherein: The cover body is a flat plate structure.

18. The battery cell according to claim 6, wherein: The cover body includes a main body and a third protrusion, the main body surrounds the outside of the third protrusion, the first protrusion surrounds the outside of the main body, and the weak portion is formed on the third protrusion; The main body includes a first inner surface and a first outer surface arranged opposite to each other, the first inner surface faces the electrode assembly, the first protrusion and the third protrusion both protrude from the first inner surface in a direction facing the electrode assembly, and the top surface of the first protrusion is closer to the first electrode tab than the top surface of the third protrusion, so as to form the avoidance gap between the current collecting component and the third protrusion for avoiding the weak portion.

19. The battery cell according to claim 18, wherein: A third recessed portion is formed on the cover body at a position corresponding to the third protrusion and is recessed from the first outer surface in a direction facing the electrode assembly. The third protrusion forms the weak portion in an area opposite to a bottom surface of the third recessed portion.

20. The battery cell according to claim 1 or 2, wherein: The cover body is provided with a groove, and a region of the cover body opposite to the groove forms the weak portion.

21. The battery cell according to claim 1 or 2, wherein: The bottom wall and the side wall are integrally formed.

22. The battery cell according to claim 1 or 2, wherein: The first electrode tab is a negative electrode tab, and the base material of the shell is steel.

23. The battery cell according to claim 1 or 2, wherein: The base material of the shell is the same as the base material of the end cover.

24. The battery cell according to claim 1 or 2, wherein: The battery cell is a cylindrical battery cell.

25. A battery comprising a plurality of battery cells according to any one of claims 1 to 24.

26. An electrical device comprising the battery according to claim 25, wherein the battery is used to provide electrical energy.

27. A method for manufacturing a battery cell, comprising: Providing a shell having an opening, the shell comprising a side wall and a bottom wall connected to the side wall, the bottom wall being provided with an electrode lead-out hole; Providing an electrode assembly and installing the electrode assembly into the housing, wherein the electrode assembly is provided with a first electrode tab at one end facing the opening and a second electrode tab having a polarity opposite to that of the first electrode tab at one end facing away from the opening; Providing an end cover, the end cover comprising a cover body and a first protrusion connected to the cover body, wherein the cover body is provided with a weak portion; Providing electrode terminals; Connecting the end cap to the housing so that the end cap covers the opening, and installing the electrode terminal in the electrode lead-out hole; The end cap is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; the first protrusion protrudes from the cover body in a direction facing the electrode assembly and is used to support the first electrode tab, so that a clearance gap is formed between the first electrode tab and the cover body to avoid the weak portion; The side wall extends along the thickness direction of the end cover and is arranged around the periphery of the electrode assembly. The end cover is electrically connected to the first electrode tab and the shell. The electrode terminal is electrically connected to the second electrode tab. The electrode terminal and the bottom wall serve as two output poles of the battery cell respectively.

28. A battery cell manufacturing system comprising: A first providing device is used to provide a shell having an opening, the shell comprising a side wall and a bottom wall connected to the side wall, the bottom wall being provided with an electrode lead-out hole; a second providing device for providing an electrode assembly and installing the electrode assembly into the housing, wherein the electrode assembly is provided with a first electrode tab at one end facing the opening and a second electrode tab having a polarity opposite to that of the first electrode tab at one end facing away from the opening; A third providing device is used to provide an end cover, wherein the end cover includes a cover body and a first protrusion connected to the cover body, and the cover body is provided with a weak portion; A fourth providing device, configured to provide electrode terminals; an assembling device for connecting the end cap to the housing so that the end cap covers the opening, and for installing the electrode terminal in the electrode lead-out hole; The end cap is configured to rupture along the weak portion when the internal pressure of the battery cell reaches a threshold value to release the internal pressure; the first protrusion protrudes from the cover body in a direction facing the electrode assembly and is used to support the first electrode tab, so that a clearance gap is formed between the first electrode tab and the cover body to avoid the weak portion; The side wall extends along the thickness direction of the end cover and is arranged around the periphery of the electrode assembly. The end cover is electrically connected to the first electrode tab and the shell. The electrode terminal is electrically connected to the second electrode tab. The electrode terminal and the bottom wall serve as two output poles of the battery cell respectively.

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