Battery monomer, battery and electric device

Abstract

The utility model discloses a battery monomer, a battery and a power utilization device. The battery monomer comprises at least one part of a positive pole piece, at least one part of a negative pole piece and at least one part of a separator which are stacked in a straight area along a first direction; a case for accommodating the electrode assembly, the case including a first wall portion; the pressure relief component is installed on the first wall part, the pressure relief component and the first wall part are welded to form a welding trace, the welding trace comprises a first trace section, the first trace section extends in the first direction, the welding trace is provided with an overlapping area, and the overlapping area is located on the first trace section. According to the technical scheme of the embodiment of the invention, the conditions of damage, cracking and the like caused by expansion of the electrode assembly at the overlapping region can be reduced, the risk of cracking and liquid leakage at the joint of the pressure relief component and the first wall part is reduced to a certain extent, and the reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] In order to ensure the safety performance of the battery cell, a pressure relief component is usually provided on the battery cell. The pressure relief component is used to release the pressure inside the battery cell when the battery cell reaches a predetermined condition. Among them, some pressure relief components are welded to the outer shell of the battery cell. During the charge and discharge process of the battery cell, the electrode assembly expands and deforms, driving the outer shell to deform, and at the same time pulling the pressure relief component, which easily causes stress concentration at the connection position between the pressure relief component and the outer shell to be cracked, reducing the reliability of the battery cell. Summary of the Utility Model

[0004] In view of the above problems, the present application provides a battery cell, a battery, and an electrical device, which can alleviate the problem of cracking at the welded joint of the pressure relief component during the use of the battery.

[0005] In a first aspect, the present application provides a battery cell, including: an electrode assembly including at least one positive electrode tab, at least one negative electrode tab, and at least one separator, the positive electrode tab, the negative electrode tab, and the separator being stacked to form a flat area, at least a part of the positive electrode tab, at least a part of the negative electrode tab, and at least a part of the separator being stacked in the flat area along a first direction; an outer shell for accommodating the electrode assembly, the outer shell including a first wall portion; a pressure relief component, the pressure relief component being installed on the first wall portion, the pressure relief component being configured to be able to release the pressure inside the battery cell; the pressure relief component is welded to the first wall portion to form a welding mark, the welding mark including a first mark segment, the first mark segment extending along the first direction, and the welding mark having an overlapping area, the overlapping area being located on the first mark segment.

[0006] In the technical solution of the embodiment of the present application, by setting the overlapping area of the welding mark on the first mark segment, the damage and cracking at the overlapping area due to the expansion of the electrode assembly can be reduced, and the risk of cracking and liquid leakage at the connection between the pressure relief component and the first wall portion can be reduced to a certain extent, improving the reliability of the battery cell.

[0007] In some embodiments, the welding trace of the pressure relief component and the first wall portion has a first end and a second end, and both the first end and the second end are disposed in the overlapping region. In the above technical solution, both the first end and the second end are located in the first trace segment. On the one hand, setting the first end and the second end at the first trace segment can reduce the pulling force of the expansion force of the electrode assembly along the first direction on the first end and the second end, and reduce the risk of cracking at the first end and the second end; on the other hand, setting the ends in the overlapping region can also make the appearance cleaner and more consistent.

[0008] In some embodiments, the welding trace of the pressure relief component and the first wall portion has a first end and a second end, and the first end is spaced from the overlapping region; and / or the second end is spaced from the overlapping region. In the above technical solution, on the one hand, the size of the overlapping region can be reduced as much as possible, and the weak area can be reduced, thereby reducing the risk of cracking at the welding joint; on the other hand, by arranging the ends at intervals from the overlapping region, the part of the welding trace with large welding power fluctuations is far away from the connection between the pressure relief component and the first wall portion, reducing the influence on the connection, making the structural strength of the connection more uniform, improving the reliability of the welding. In addition, with such a design, the welding process is simpler and more convenient for manufacturing and forming.

[0009] In some embodiments, the spacing distance between the first end and the overlapping region is greater than or equal to 0.5 mm, and / or the spacing distance between the second end and the overlapping region is greater than or equal to 0.5 mm. In the above technical solution, by appropriately increasing the distance between the end and the overlapping region, the part of the welding trace with large welding power fluctuations is further away from the connection between the pressure relief component and the first wall portion, reducing the influence on the connection, making the connection strength more uniform, and improving the reliability of the welding.

[0010] In some embodiments, the first end is only located on the first wall portion, and / or the second end is only located on the first wall portion. In the above technical solution, the part of the welding trace with large welding power fluctuations is far away from the connection between the pressure relief component and the first wall portion, reducing the influence on the connection, making the connection strength more uniform, and improving the reliability of the welding; in addition, the end being located on the first wall portion can reduce the influence of the end on the pressure relief component, and to a certain extent avoid the problem that the welding trace contacts the notch and affects the notch strength, improving the reliability of the pressure relief component.

[0011] In some embodiments, the penetration depth of the first end is less than the penetration depth of the overlapping region; and / or the penetration depth of the second end is less than the penetration depth of the overlapping region. In the above technical solution, by reducing the penetration depth of the end, the risk of burn-through cracking at the end is reduced.

[0012] In some embodiments, the penetration depth of the welding mark is L, and the thickness dimension of the first wall portion is H, satisfying: 0.2 mm ≤ L < H. In the above technical solution, the probability of the battery cell being scrapped during welding can be reduced, and at the same time, the probability of the battery cell being easily cracked during normal use can be reduced, improving the reliability of the battery cell.

[0013] In some embodiments, 0.2 mm ≤ L ≤ 0.9 mm. In the above technical solution, the probability of the battery cell being scrapped during welding can be further reduced, and at the same time, the probability of the battery cell being easily cracked during normal use can be reduced, improving the reliability of the battery cell.

[0014] In some embodiments, the thickness dimension of the first wall portion is H, satisfying 1.5 mm ≤ H ≤ 2.5 mm. In the above technical solution, the space for accommodating the electrode sheet can be increased to a certain extent, so that more electrode sheets can be accommodated in the outer shell of the battery cell, improving the energy density of the battery cell. At the same time, the strength of the first wall portion can be increased to a certain extent, reducing the deformation amount of the first wall portion, and further reducing the pulling on the welding mark, etc., improving the reliability of the overall structure.

[0015] In some embodiments, the welding mark includes a second trace segment and two relatively arranged first trace segments. The extending direction of the second trace segment is perpendicular to the first direction, and both ends of the second trace segment are respectively connected to the two first trace segments. In the above technical solution, the connection between the second trace segment and the two first trace segments can form a more secure welding node, improving the strength of the overall connection.

[0016] In some embodiments, there are two second trace segments, and the two second trace segments are arranged opposite to each other along the first direction. Both ends of each second trace segment are respectively connected to the two first trace segments. In the above technical solution, the first trace segment and the second trace segment enclose a complete ring, and the outer periphery of the pressure relief component can be welded to the first wall portion, improving the reliability of the connection.

[0017] In some embodiments, the first trace segment is an arc segment. In the above technical solution, the arc-shaped first trace segment can better adapt to the curvature of the pressure relief component, providing a smoother and more continuous connection. The arc shape helps to more evenly distribute the welding stress, reducing stress concentration points, reducing the risk of stress concentration and cracks, and improving reliability.

[0018] In some embodiments, along the thickness direction of the first wall portion, the first wall portion has a first surface and a second surface which are oppositely arranged. The first wall portion is provided with a receiving groove that is recessed from the first surface towards the second surface. A pressure relief hole is provided at the bottom of the receiving groove. At least a part of the pressure relief component is located in the receiving groove, and is welded to the groove wall of the receiving groove to form the welding mark. In the above technical solution, the receiving groove provides a specific space for the pressure relief component, enabling it to be arranged within the first wall portion, that is, providing additional space without increasing the external dimensions of the battery cell. The pressure relief hole is provided at the bottom of the receiving groove, and at least a part of the pressure relief component is located in the receiving groove. When the internal pressure of the battery cell reaches the threshold value, the pressure relief component opens the pressure relief hole to discharge the discharge medium inside the battery cell, achieving pressure relief. The pressure relief component is connected to the groove wall of the receiving groove by welding, ensuring the firm fixation between the pressure relief component and the first wall portion, and at the same time improving the sealing performance of the overall structure.

[0019] In some embodiments, the receiving groove includes multiple levels of grooves arranged in sequence from the first surface towards the second surface. Among two adjacent levels of grooves, the level of groove farther from the first surface is arranged on the groove bottom surface of the level of groove closer to the first surface. The groove bottom surface of the level of groove that is farthest from the first surface among the multiple levels of grooves has the pressure relief hole. The pressure relief component is arranged in one of the levels of grooves among the multiple levels of grooves, and is welded to the side wall surface of the level of groove. In the above technical solution, the level of groove can play a role in positioning the pressure relief component, enabling the pressure relief component to be properly supported and fixed, and thus facilitating subsequent welding. The pressure relief component is welded to the side wall surface of the level of groove, improving the stability of the pressure relief component, and enhancing the sealing performance of the connection between the first wall portion and the pressure relief component and the integrity of the overall structure.

[0020] In some embodiments, the pressure relief component is provided with a predetermined pressure relief area and a scoring groove. The predetermined pressure relief area has a predetermined opening boundary, and the predetermined opening boundary is surrounded by the outer edge of the positive projection of at least a part of the scoring groove in the second direction; or the predetermined opening boundary is surrounded by the connection lines between multiple ends of the scoring groove; or the predetermined opening boundary is surrounded by the connection lines between multiple ends of the scoring groove and the outer edge of the positive projection of at least a part of the scoring groove in the second direction. The second direction is the thickness direction of the first wall portion and is perpendicular to the first direction. In the above technical solution, by adopting the scoring groove with the above structure, it is beneficial for the rapid pressure relief of the pressure relief portion.

[0021] In some embodiments, the housing includes a shell and an end cap, wherein at least one side of the shell has an opening, the end cap is connected to the shell and is used to close the opening, and the first wall portion is formed on the shell. By disposing the pressure relief component on the shell, the structure of the end cap can be simplified, and the distance between the pressure relief component and the main body of the electrode assembly can be shortened. This can further shorten the path for the discharge medium to flow to the pressure relief component during pressure relief, shortening the time it takes for the discharge medium to reach the pressure relief component, thereby improving the timeliness of pressure relief of the battery cell and effectively improving the reliability of the battery cell.

[0022] In some embodiments, the first wall portion is disposed opposite the end cap. In the above technical solution, the pressure relief component is installed at a position opposite the end cap, thereby shortening the distance between the pressure relief component and the main body of the electrode assembly. This can further shorten the path for the discharge medium to flow to the pressure relief component during pressure relief, shorten the time it takes for the discharge medium to reach the pressure relief component, improve the timeliness of pressure relief of the battery cell, and thus effectively improve the reliability of the battery cell.

[0023] In some embodiments, the housing has openings on opposite sides, and the two end caps are used to close the openings on the corresponding sides. In the above technical solution, by providing two openings on the housing, it is possible to facilitate the manufacturing and molding of the housing, and at the same time facilitate the extension of the electrode tabs from both ends of the electrode assembly, thereby facilitating the separation of the two electrical connections and reducing the risk of short circuits in the battery cells.

[0024] In some embodiments, the end cap is provided with an electrical connection portion, and the electrical connection portion is electrically connected to the positive electrode plate, or the electrical connection portion is electrically connected to the negative electrode plate.

[0025] In some embodiments, the end cap is provided with an extraction hole, and the electrical connection portion includes a terminal body, a first limiting portion, and a second limiting portion. The terminal body connects the first limiting portion and the second limiting portion, and the terminal body is inserted into the extraction hole. Along the first direction, the first limiting portion is located on the side of the end cap facing away from the electrode assembly, and the second limiting portion is located on the side of the end cap facing the electrode assembly. In the above technical solution, the electrical connection portion of this structure can be installed on the end cap by riveting, which is easy to install and more economical.

[0026] In some embodiments, the first wall portion is used to support the electrode assembly and is located below the electrode assembly. In the above technical solution, the pressure relief component can be provided at the bottom of the battery cell, and the bottom of the battery cell can be provided with an exhaust channel, which can be connected to the pressure relief portion to discharge high-temperature and high-pressure flue gas through the pressure relief component at the bottom into the exhaust channel and then to the outside when thermal runaway of the battery cell occurs.

[0027] In some embodiments, the electrode assembly has a laminated structure. The electrode assembly includes a plurality of the positive electrode plates and a plurality of the negative electrode plates, and the plurality of positive electrode plates and the plurality of negative electrode plates are laminated along the first direction. In the above technical solution, the laminated electrode assembly has a more compact structure and stronger anti-extrusion ability.

[0028] In some embodiments, the number of the negative electrode plates is greater than the number of the positive electrode plates, and one positive electrode plate is disposed between two adjacent negative electrode plates.

[0029] In some embodiments, each negative electrode plate is provided with a negative electrode tab; and / or each positive electrode plate is provided with a positive electrode tab.

[0030] In a second aspect, the present application provides a battery, which includes the battery cell in the above embodiments.

[0031] In a third aspect, the present application provides an electrical device, which includes the battery in the above embodiments, and the battery is used to provide electrical energy.

[0032] The above description is only an overview of the technical solutions of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically illustrates the specific embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0034] Figure 1 is a schematic diagram of an electrical device in the related art;

[0035] Figure 2 is a schematic diagram of a battery in the related art;

[0036] Figure 3 is a schematic diagram of a battery cell provided by some embodiments of the present application;

[0037] Figure 4 is an exploded view of a battery cell provided by some embodiments of the present application;

[0038] Figure 5 is a schematic diagram of an electrode assembly provided by some embodiments of the present application;

[0039] Figure 6Schematic diagram of the electrode assembly provided in some other embodiments of the present application;

[0040] Figure 7 Schematic diagram of the connection between the pressure relief component and the housing provided in some embodiments of the present application;

[0041] Figure 8 In some embodiments of the present application Figure 7 Schematic diagram of the partial structure shown;

[0042] Figure 9 In some other embodiments of the present application Figure 7 Schematic diagram of the partial structure shown;

[0043] Figure 10 In some other embodiments of the present application Figure 7 Schematic diagram of the partial structure shown;

[0044] Figure 11 Cross-sectional view of the housing provided in some embodiments of the present application;

[0045] Figure 12 Partial cross-sectional view of the electrode assembly provided in some embodiments of the present application;

[0046] Figure 13 Is Figure 12 Enlarged view of the circled area A in;

[0047] Figure 14 Is Figure 13 Enlarged view of the circled area B in;

[0048] Figure 15 Schematic diagram of the connection between the end cover and the electrical connection part provided in some embodiments of the present application;

[0049] Figure 16 Schematic diagram of the pressure relief component provided in some embodiments of the present application;

[0050] Figure 17 Schematic diagram of the pressure relief component provided in some other embodiments of the present application;

[0051] Figure 18 Schematic diagram of the pressure relief component provided in some other embodiments of the present application.

[0052] Reference numerals:

[0053] Battery 1000, vehicle 2000, battery cell 100, box 200, first part 201, first part 202,

[0054] Housing 10, housing body 101, end cover 102, first wall portion 11, first surface 11a, second surface 11b, pressure relief hole 111, receiving groove 112, second wall portion 12,

[0055] Electrode assembly 20, positive electrode tab 21, negative electrode tab 22, straight region 23, turning region 24, separator 25,

[0056] Electrical connection part 30, terminal body 31, first limiting part 32, second limiting part 33, first insulating part 6, second insulating part 7,

[0057] Pressure relief component 40, predetermined pressure relief area 401, scoring groove 41, first arc segment 411, first straight segment 412, second straight segment 413, third straight segment 414, arc segment 415, fourth straight segment 416, fifth straight segment 417, sixth straight segment 418, seventh straight segment 419 (flipping score 419),

[0058] Welding mark 50, first mark segment 51, second mark segment 52, overlapping area 53, first end 501, second end 502,

[0059] Patch 60. Detailed implementation manners

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, rather than all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0061] Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the technical field to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0062] References to "embodiments" in this application mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment every time, nor are they independent or alternative embodiments mutually exclusive of other embodiments. The term "and / or" in this application is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone. Additionally, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0063] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components shown in the drawings in the embodiments of this application, as well as the overall thickness, length, width, etc. of the integrated device, are only for illustrative purposes and should not constitute any limitation to this application.

[0064] The term "a plurality of" as used in this application refers to two or more (including two).

[0065] In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging so that the active material can be reused.

[0066] The battery cell can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium-metal battery, a sodium-metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of this application are not limited thereto.

[0067] The battery mentioned in the embodiments of this application can include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or in a hybrid connection through a busbar component.

[0068] In some embodiments, the battery can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. In some embodiments, the battery can be a battery pack, which includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0069] In some embodiments, the box body can be part of the chassis structure of a vehicle. For example, part of the box body can become at least part of the floor of the vehicle, or part of the box body can become at least part of the crossbeam and longitudinal beam of the vehicle.

[0070] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0071] The development of battery technology needs to consider various design factors simultaneously. For example, performance parameters such as energy density, cycle life, discharge capacity, charge and discharge rate, etc. In addition, the safety performance of the battery also needs to be considered.

[0072] In a battery cell, to ensure the safety performance of the battery cell, a pressure relief component can be provided on the outer shell of the battery cell. When the battery cell undergoes thermal runaway, the pressure inside the battery cell is released through the pressure relief component to improve the safety of the battery cell.

[0073] Some pressure relief components are welded to the outer shell of the battery cell. During the charge and discharge process of the battery cell, the electrode assembly will expand, causing the outer shell to bulge and deform. The bulge of the outer shell will be transmitted to the surface where the pressure relief component is located, driving the surface where the pressure relief component is located to produce concave and tensile deformation. Especially in the direction where the expansion of the electrode assembly is large, a large strain will occur at the connection between the pressure relief component and the outer shell, resulting in stress concentration and cracking at the connection.

[0074] In view of this, an embodiment of the present application provides a battery cell, including: an electrode assembly, including at least one positive electrode tab, at least one negative electrode tab, and at least one separator. The positive electrode tab, the negative electrode tab, and the separator are stacked to form a flat area. At least a part of the positive electrode tab, at least a part of the negative electrode tab, and at least a part of the separator are stacked in the flat area along a first direction; an outer shell for accommodating the electrode assembly, the outer shell including a first wall portion; a pressure relief component, the pressure relief component is installed on the first wall portion, and the pressure relief component is configured to be able to release the pressure inside the battery cell; the pressure relief component is welded to the first wall portion to form a welding mark, the welding mark includes a first mark segment, the first mark segment extends along the first direction, and the welding mark has an overlapping area, and the overlapping area is located on the first mark segment.

[0075] In such a battery cell, by setting the overlapping area of the welding mark on the first mark segment, the damage and cracking at the overlapping area caused by the expansion of the electrode assembly can be reduced, and to a certain extent, the risk of cracking and liquid leakage at the connection between the pressure relief component and the first wall portion can be reduced, improving the reliability of the battery cell.

[0076] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries. The electrical devices may be vehicles, mobile phones, portable devices, laptop computers, ships, spacecrafts, electric toys, and electric tools, etc. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range electric vehicle, etc.; the spacecraft includes airplanes, rockets, space shuttles, and spaceships, etc.; the electric toys include fixed or mobile electric toys, for example, game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, etc.; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, for example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose special restrictions on the above electrical devices.

[0077] For the convenience of description, the following embodiments will take the electrical device as a vehicle as an example for illustration.

[0078] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle 2000 provided by some embodiments of the present application. A battery 1000 is disposed inside the vehicle 2000, and the battery 1000 may be disposed at the bottom, head, or tail of the vehicle 2000. The battery 1000 can be used to supply power to the vehicle 2000. For example, the battery 1000 can be used as the operating power source of the vehicle 2000.

[0079] The vehicle 2000 may further include a controller and a motor. The controller is used to control the battery 1000 to supply power to the motor. For example, it is used for the working power requirements during the start, navigation, and driving of the vehicle 2000.

[0080] In some embodiments of the present application, the battery 1000 can not only be used as the operating power source of the vehicle 2000, but also be used as the driving power source of the vehicle 2000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 2000.

[0081] Please refer to Figure 2 , Figure 2 which is an exploded view of the battery 1000 provided by some embodiments of the present application. The battery 1000 includes battery cells 100 and a box body 200, and the box body 200 is used to accommodate the battery cells 100.

[0082] Among them, the battery box 200 is a component for accommodating the battery cells 100. The battery box 200 provides a placement space for the battery cells 100, and the battery box 200 can adopt various structures. In some embodiments, the battery box 200 may include a first part 201 and a second part 202. The first part 201 and the second part 202 cover each other to define a placement space for accommodating the battery cells 100. The first part 201 and the second part 202 can be of various shapes, such as a cuboid, a cylinder, etc. The first part 201 can be a hollow structure with one side open, and the second part 202 can also be a hollow structure with one side open. When the open side of the second part 202 covers the open side of the first part 201, the battery box 200 with a placement space is formed. It can also be that the first part 201 is a hollow structure with one side open and the second part 202 is a plate-like structure. When the second part 202 covers the open side of the first part 201, the battery box 200 with a placement space is formed. As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell or a battery cell 100 of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc. There is no special limitation in this application.

[0083] In the battery 1000, the battery cells 100 can be one or multiple. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, in parallel or in a hybrid connection. A hybrid connection means that there are both series and parallel connections among the multiple battery cells 100. It can be that multiple battery cells 100 are first connected in series, in parallel or in a hybrid connection to form a battery module, and then multiple battery modules are connected in series, in parallel or in a hybrid connection to form a whole and are accommodated in the battery box 200. It can also be that all the battery cells 100 are directly connected in series, in parallel or in a hybrid connection together, and then the whole formed by all the battery cells 100 is accommodated in the battery box 200.

[0084] Please refer to Figure 3 and Figure 4 , Figure 3 which is a schematic diagram of the battery cell 100 provided in some embodiments of this application; Figure 4 which is an exploded view of the battery cell 100 provided in some embodiments of this application. The battery cell 10 can include a housing 10 and an electrode assembly 20.

[0085] The housing 10 is used to accommodate components such as the electrode assembly 20 and the electrolyte. The housing 10 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite housing) or an aluminum-plastic film, etc. As an example, the housing 10 may include a housing body 101 and an end cap 102.

[0086] The housing 101 can be a hollow structure with an opening formed at one end, or it can also be a hollow structure with openings formed at opposite ends. The material of the housing 101 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0087] The end cap 102 is a component that closes the opening of the housing 101 to isolate the internal environment of the battery cell 100 from the external environment. The end cap 102 and the housing 101 together define a receiving space for accommodating the electrode assembly 20, the electrolyte, and other components. The end cap 102 can be connected to the housing 101 by welding or crimping to close the opening of the housing 101. The shape of the end cap 102 can be adapted to the shape of the outer shell 10. For example, when the housing 101 is a cuboid structure, the end cap 102 is a rectangular plate-like structure adapted to the outer shell 10. The material of the end cap 102 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0088] In the battery cell 10, there can be one or two end caps 102. In an embodiment where the housing 101 is a hollow structure with openings formed at both ends, two end caps 102 can be correspondingly provided. The two end caps 102 respectively close the two openings of the housing 101, and the two end caps 102 and the housing 101 together define the receiving space. In an embodiment where the housing 101 is a hollow structure with an opening formed at one end, one end cap 102 can be correspondingly provided. The end cap 102 closes the opening at one end of the housing 101, and one end cap 102 and the housing 101 together define the receiving space.

[0089] The electrode assembly 20 includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell 100, active ions (such as lithium ions) intercalate and deintercalate back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can prevent the short circuit between the positive and negative electrodes and at the same time allow the active ions to pass through.

[0090] In some embodiments, the positive electrode can be the positive electrode tab 21. The positive electrode tab 22 can include a positive electrode current collector and a positive electrode active material region provided on at least one surface of the positive electrode current collector. The positive electrode active material region has a positive electrode active material.

[0091] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material region is provided on either or both of the two opposite surfaces of the positive electrode current collector.

[0092] In some embodiments, the negative electrode can be the negative electrode tab 22. The negative electrode tab 22 can include a negative electrode current collector and a negative electrode active material region provided on at least one surface of the negative electrode current collector.

[0093] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material region is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0094] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0095] In some embodiments, the electrode assembly 20 further includes a separator disposed between the positive electrode and the negative electrode.

[0096] In some embodiments, the separator is a separator film. The present application does not particularly limit the type of the separator film, and any publicly known porous structure separator film with good chemical stability and mechanical stability can be selected.

[0097] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0098] In some embodiments, the battery cell 100 further includes an electrolyte, which functions to conduct ions between the positive and negative electrodes. The present application does not specifically limit the type of the electrolyte, and it can be selected according to requirements. The electrolyte can be liquid, gel-like or solid.

[0099] In some embodiments, the electrode assembly 20 is a wound structure. The positive electrode plate, the negative electrode plate and the separator are wound into a wound structure.

[0100] In some embodiments, the electrode assembly 20 is a stacked structure.

[0101] As an example, a plurality of positive electrode plates 21, negative electrode plates 22 and separators 25 can be respectively provided, and the plurality of positive electrode plates 21, the plurality of negative electrode plates 22 and the plurality of separators 25 are alternately stacked.

[0102] As an example, a plurality of separators can be provided and are respectively disposed between any adjacent positive electrode plates or negative electrode plates.

[0103] As an example, the separator can be continuously provided and is disposed between any adjacent positive electrode plates or negative electrode plates by means of folding or winding.

[0104] In some embodiments, the shape of the electrode assembly 20 can be flat or multi-prismatic, etc.

[0105] In some embodiments, the electrode assembly 20 is provided with tabs, and the tabs can lead the current out of the electrode assembly 20. The tabs include a positive tab and a negative tab.

[0106] The battery cell 100 may further include an electrical connection portion 30. The electrical connection portion 30 may be disposed on the housing 10 and is used for electrically connecting with the tab of the electrode assembly 20 to output the electrical energy of the battery cell 10. The electrical connection portion 30 and the tab may be directly connected. For example, the electrical connection portion 30 and the tab are directly welded. The electrical connection portion 30 and the tab may also be indirectly connected. For example, the electrical connection portion 30 and the tab are indirectly connected through a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0107] As Figure 3 and Figure 4 shown, taking the hollow structure with an opening formed at one end by the housing 101 as an example, two electrical connection portions 30 may be provided on the end cap 102. The two electrical connection portions 30 are a positive electrical connection portion and a negative electrical connection portion respectively. The positive electrical connection portion is electrically connected to the positive tab, and the negative electrical connection portion is electrically connected to the negative tab.

[0108] Please refer to Figure 5 and Figure 6 , Figure 5 which is a schematic diagram of the electrode assembly 20 provided by some embodiments of the present application; Figure 6 which is a schematic diagram of the electrode assembly 20 provided by other embodiments of the present application. The electrode assembly 20 includes a positive electrode plate 21, a negative electrode plate 22 and a separator 25. The positive electrode plate 21 includes a positive electrode main body and a positive tab. The positive tab extends from one end of the positive electrode main body. Most of the area of the positive tab is not coated with positive electrode active material, and most of the area of the positive electrode main body is coated with positive electrode active material. The negative electrode plate 22 includes a negative electrode main body and a negative tab. The negative tab extends from one end of the negative electrode main body. Most of the area of the negative tab is not coated with negative electrode active material, and most of the area of the negative electrode main body is coated with negative electrode active material. The positive electrode main body and the negative electrode main body constitute the main body portion of the electrode assembly.

[0109] As Figure 5 shown, the electrode assembly 20 includes a plurality of electrode plates arranged in a winding manner. The electrode assembly 20 includes a flat region 23 and a turning region 24 connected to the end of the flat region 23.

[0110] The plurality of electrode plates arranged in a winding manner, that is, the positive electrode plate 21, the negative electrode plate 22 and the separator 25 are stacked and then wound around a set axis to form the electrode assembly 20. The flat region 23 refers to the part where the electrode plates extend along a plane after winding; the turning region 24 refers to the part where the electrode plates extend along an arc surface after winding. For example Figure 5 shown, the part between the front surface and the rear surface of the electrode assembly 20 forms the flat region 23. The extending direction of the electrode plates in the flat region 23 is the length direction of the flat region 23. As Figure 5 shown, the left and right end portions of the flat region 23 are the turning regions 24.

[0111] AsFigure 6 As shown, the electrode assembly 120 includes a plurality of electrode sheets arranged in a stacked manner, and the electrode assembly 20 has a flat region 23.

[0112] A plurality of electrode sheets arranged in a stacked manner, for example, at least one positive electrode sheet 21, at least one negative electrode sheet 22, and a separator 25 are stacked and arranged to form the electrode assembly 20. The flat region 23 is formed by stacking at least a part of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 25, or may be formed by stacking at least a part of the positive electrode sheet 21 and the negative electrode sheet 22 and the separator 25.

[0113] Please refer to Figures 7 - 14 , the battery cell 100 according to an embodiment of the present application includes: an electrode assembly 20, including at least one positive electrode sheet 21, at least one negative electrode sheet 22, and at least one separator 25. The positive electrode sheet 21, the negative electrode sheet 22, and the separator 25 are stacked to form a flat region 23. At least a part of the positive electrode sheet 21, at least a part of the negative electrode sheet 22, and at least a part of the separator 25 are stacked in the flat region 23 along a first direction F1.

[0114] The electrode assembly 20 may be a stacked type, that is, a plurality of electrode sheets of the electrode assembly 20 are arranged in a stacked manner. After the electrode sheets are stacked, a flat region 23 is formed. The electrode assembly 20 is in a stacked state as a whole. In the flat region 23, at least a part of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 25 are stacked along the first direction F1. Therefore, the expansion and deformation of the electrode assembly 20 are particularly obvious in the first direction F1.

[0115] The electrode assembly 20 may also be a wound type. The positive electrode sheet 21 and the negative electrode sheet 22 of the electrode assembly 20 are superposed with the separator 25 and wound into a shape, and a flat region 23 and a turning region 24 are formed. The flat region 23 refers to the part where the electrode sheets extend along a plane after winding. The part of the electrode assembly 20 in the flat region 23 is in a stacked state; the turning region 24 refers to the part where the electrode sheets extend along an arc surface after winding. At least a part of the outer surface of the turning region 24 is an arc surface. The flat region 23 connects two turning regions 24. In the flat region 23, a part of the positive electrode sheet 21, a part of the negative electrode sheet 22, and a part of the separator 25 are stacked along the first direction F1. For example, after winding, each layer of the positive electrode sheet 21, each layer of the negative electrode sheet 22, and each layer of the separator 25 can be penetrated by a straight line extending along the first direction F1. Therefore, the expansion and deformation of the electrode assembly 20 are particularly obvious in the first direction F1.

[0116] The battery cell 100 further includes a housing 10. The housing 10 is used to accommodate the electrode assembly 20, and the housing 10 includes a first wall portion 11.

[0117] The housing 10 refers to the outermost structural member of the battery cell 100. The electrode assembly 20, electrolyte, etc. are accommodated in the housing 10. The electrode assembly 20 accommodated therein can be one or multiple.

[0118] The housing 10 includes a first wall portion 11 and two second wall portions 12. The two second wall portions 12 are respectively located on both sides of the electrode assembly 20 in the first direction F1. Most of the expansion of the electrode assembly 20 acts on the second wall portions 12. The first wall portion 11 is located on one side of the electrode assembly 20 in the second direction F2. The second direction F2 is perpendicular to the first direction F1. The thickness direction of the first wall portion 11 is the second direction F2. A pressure relief component 40 is provided on the first wall portion 11.

[0119] The battery cell 100 further includes a pressure relief component 40. The pressure relief component 40 is installed on the first wall portion 11 and is configured to be able to relieve the pressure inside the battery cell 100.

[0120] The pressure relief component 40 is a component for relieving the pressure inside the battery cell 100. When the internal pressure of the battery cell 100 reaches a threshold value, the discharge medium inside the battery cell 100 can be discharged through the pressure relief component 40 to achieve the purpose of pressure relief. This threshold value is designed differently according to different design requirements and may depend on one or more materials of the positive electrode tab 21, negative electrode tab 22, electrolyte, and separator in the battery cell 100.

[0121] The pressure relief component 40 is welded to the first wall portion 11 to form a welding mark 50. The welding mark 50 includes a first mark segment 51. The first mark segment 51 extends along the first direction F1. The welding mark 50 has an overlapping area 53. The overlapping area 53 is located on the first mark segment 51.

[0122] The pressure relief component 40 is welded to the first wall portion 11 to form a welding mark 50. The welding mark 50 refers to the joint area formed by connecting two or more components together by melting or crimping during the welding process.

[0123] The welding mark 50 includes a first mark segment 51. The first mark segment 51 can be a straight line segment. Among them, the first mark segment 51 extends along the first direction F1. Here, the extension direction of the first mark segment 51 can be inclined to the first direction F1, the extension direction of the first mark segment 51 can also be parallel to the first direction F1, and the extension direction of the first mark segment 51 is not perpendicular to the first direction F1.

[0124] The first trace segment 51 can also be an arc segment. Here, the first trace segment 51 extends along the first direction F1. One end of the first trace segment 51 can be located on one side of the other end of the first trace segment 51 in the first direction F1. The first trace segment 51 extends from one end to the other end along the first direction F1. The tangent at any point on the first trace segment 51 can be inclined to the first direction F1, the tangent at a point on the first trace segment 51 can also be parallel to the first direction F1, and the tangent at any point on the first trace segment 51 is not perpendicular to the first direction F1.

[0125] Since there may be overlapping welding traces during the welding process, the area of the overlapping welding traces is the overlapping area 53. For example, the pressure relief component 40 can be laser welded to the first wall portion 11. Here, the overlapping area 53 is the area irradiated by the laser twice, and welding is performed twice in this area, and the strength of this area is relatively weak. The strength at the overlapping area 53 is relatively weak.

[0126] When the battery cell 100 is deformed due to the expansion of the electrode assembly 20 during charge and discharge, the expansion deformation of the electrode assembly 20 is particularly obvious in the first direction F1, and the first trace segment 51 extends along the first direction. The deformation at the first trace segment 51 is relatively small. Therefore, by setting the overlapping area 53 at the first trace segment 51, the overlapping area 53 can be reduced from being pulled by the expansion force of the electrode assembly 20 along the first direction F1, and the risk of cracking at the overlapping area 53 can be reduced.

[0127] In the technical solution of the embodiment of the present application, by setting the overlapping area 53 of the welding trace 50 at the first trace segment 51, the situations such as breakage and cracking at the overlapping area 53 due to the expansion of the electrode assembly 20 can be reduced, and the risk of cracking and liquid leakage at the connection between the pressure relief component 40 and the first wall portion 11 can be reduced to a certain extent, and the reliability of the battery cell 100 can be improved.

[0128] In addition, when the pressure relief component 40 is welded to the first wall portion 11, various visible or invisible marks are left on the surface or near-surface area of the material during the welding process due to thermal effects, physical effects, or other related processes. Among them, the welding trace 50 can be a weld seam, and the weld seam connects the pressure relief component 40 and the first wall portion 11. It can also be other marks during the welding process, that is, the welding trace 50 can only include the weld seam. For example, the welding trace 50 has a first end 501 and a second end 502, and both the first end 501 and the second end 502 can be set at the weld seam; the welding trace 50 can also include the weld seam and other marks, and part of the welding trace can be located outside the welding trace 50. For example, one of the first end 501 and the second end 502 can be set at the weld seam, and the other can be set outside the weld seam, or both ends are spaced from the weld seam.

[0129] Such as Figure 8As shown, in some embodiments, the welding trace 50 of the pressure relief component 40 and the first wall portion 11 has a first end 501 and a second end 502, and both the first end 501 and the second end 502 are disposed in the overlapping region 53.

[0130] The first end 501 can be the starting end of welding, and the second end 502 can be the ending end of welding; the first end 501 can also be the ending end of welding, and the second end 502 can be the starting end of welding. At the start and end of welding, the welding power fluctuates greatly. Affected by the welding power fluctuation, welding defects are more likely to occur at the ends. By disposing both the first end 501 and the second end 502 in the overlapping region 53, both the first end 501 and the second end 502 are located in the first trace segment 51. On the one hand, setting the first end 501 and the second end 502 at the first trace segment 51 can reduce the pulling force of the expansion force of the electrode assembly 20 along the first direction F1 on the first end 501 and the second end 502, and reduce the risk of cracking at the first end 501 and the second end 502; on the other hand, setting the ends in the overlapping region 53 can also make the appearance cleaner and more consistent.

[0131] As Figure 9 shown, in some embodiments, the welding trace of the pressure relief component 40 and the first wall portion 11 has a first end 501 and a second end 502, and the first end 501 and the overlapping region 53 are spaced apart.

[0132] The first end 501 can be the starting end of welding, and the first end 501 can also be the ending end of welding. As Figure 9 shown, the first end 501 is located outside the overlapping region 53, and the overlapping region 53 extends along an arc. The welding trace can extend in a straight line direction to the first end 501. On the one hand, the size of the overlapping region 53 can be reduced as much as possible, and the weak area can be reduced, thereby reducing the risk of cracking at the welding position; on the other hand, by arranging the first end 501 at an interval from the overlapping region 53, the part of the welding trace with large welding power fluctuation is far away from the connection 50 between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection, making the structural strength of the connection more uniform, and improving the reliability of welding. In addition, with such a design, the welding process is simpler and more convenient for manufacturing and forming.

[0133] In some embodiments, the spacing distance between the first end 501 and the overlapping region 53 is greater than or equal to 0.5 mm.

[0134] In the extending direction of the welding trace, the minimum distance L1 by which the first end portion 501 exceeds the overlapping region 53 is 0.5 mm, or L1 is greater than 0.5 mm. By appropriately increasing the distance between the first end portion 501 and the overlapping region 53, the portion of the welding trace with a relatively large welding power fluctuation is further away from the connection between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection, making the strength of the connection more uniform, and improving the reliability of welding.

[0135] In some embodiments, the second end portion 502 and the overlapping region 53 are arranged at intervals.

[0136] The second end portion 502 can be a welding termination end, or the second end portion 502 can be a welding starting end. In some examples, the second end portion 502 is located outside the overlapping region 53, and the overlapping region 53 extends along an arc. The welding trace can extend in a straight line direction to the second end portion 502. On the one hand, the size of the overlapping region 53 can be minimized as much as possible, reducing the weak area, and thus reducing the risk of cracking at the welding point. On the other hand, by arranging the second end portion 502 at an interval from the overlapping region 53, the portion of the welding trace with a relatively large welding power fluctuation is away from the connection between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection, making the structural strength of the connection more uniform, and improving the reliability of welding. In addition, with such a design, the welding process is simpler and more convenient for manufacturing and forming.

[0137] In some embodiments, the spacing distance between the second end portion 502 and the overlapping region 53 is greater than or equal to 0.5 mm.

[0138] In the extending direction of the welding trace, the minimum distance L2 by which the second end portion 502 exceeds the overlapping region 53 is 0.5 mm, or L2 is greater than 0.5 mm. By appropriately increasing the distance between the second end portion 502 and the overlapping region 53, the portion of the welding trace with a relatively large welding power fluctuation is further away from the connection between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection, making the strength of the connection more uniform, and improving the reliability of welding.

[0139] In some embodiments, both the first end portion 501 and the second end portion 502 are arranged at intervals from the overlapping region 53.

[0140] Such as Figure 10As shown, the first end portion 501 and the second end portion 502 are located outside the overlapping region 53, whereby the size of the overlapping region 53 can be further reduced, the weak region can be reduced, and further the risk of cracking at the welded joint can be reduced; on the other hand, the first end portion 501 and the second end portion 502 are arranged at intervals from the overlapping region 53, and the welding trace portion with large welding power fluctuations is far away from the connection portion between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection portion, making the structural strength of the connection portion more uniform, improving the reliability of welding. In addition, with such a design, the welding process is simpler and convenient for manufacturing and forming.

[0141] As Figure 9 and Figure 10 shown, in some embodiments, the first end portion 501 is only located on the first wall portion 11.

[0142] Thus, the first end portion 501 can be arranged at intervals from the overlapping region 53, and the welding trace portion with large welding power fluctuations is far away from the connection portion between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection portion, making the connection more uniform, and improving the reliability of welding; in addition, the first end portion 501 is located on the first wall portion 11, which can reduce the influence of the first end portion 501 on the pressure relief component 40, and to a certain extent avoid the problem that the welding trace contacts the notch 41 and affects the strength of the notch 41, improving the reliability of the pressure relief component 40.

[0143] As Figure 10 shown, in some embodiments, the second end portion 502 is only located on the first wall portion 11.

[0144] Thus, the second end portion 502 can be arranged at intervals from the overlapping region 53, and the welding trace portion with large welding power fluctuations is far away from the connection portion between the pressure relief component 40 and the first wall portion 11, reducing the influence on the connection portion, making the structural strength of the connection portion more uniform, and improving the reliability of welding; in addition, the second end portion 502 is located on the first wall portion 11, which can reduce the influence of the second end portion 502 on the pressure relief component 40, and to a certain extent avoid the problem that the welding trace 50 contacts the notch 41 and affects the strength of the notch 41, improving the reliability of the pressure relief component 40.

[0145] In some embodiments, the penetration depth of the first end portion 501 is less than the penetration depth of the overlapping region 53.

[0146] The first end portion 501 can be the welding start end, and the first end portion 501 can also be the welding end. At the start and end of welding, the welding power fluctuates greatly. Affected by the welding power fluctuation, welding defects are more likely to occur at the end portion. By reducing the penetration depth of the first end portion 501, the risk of burn-through and cracking at the first end portion 501 is reduced.

[0147] In some embodiments, the penetration depth of the second end portion 502 is less than the penetration depth of the overlapping region 53.

[0148] The second end portion 502 can be a welding termination end, or it can also be a welding starting end. During welding start and termination, the welding power fluctuates greatly. Affected by the welding power fluctuation, it is easier to have poor welding at the end portion. By reducing the penetration depth of the second end portion 502, the risk of burn-through cracking at the second end portion 502 is reduced.

[0149] As Figure 14 shown, in some embodiments, the penetration depth of the welding trace 50 is L, and the thickness dimension of the first wall portion 11 is H, satisfying: 0.2 mm ≤ L < H.

[0150] As Figure 14 shown, the pressure relief component 40 is welded to the first wall portion 11 to form the welding trace 50. The penetration depth of the welding trace 50 is L. When the penetration depth of the weld 50 is too small, the welding depth of the welding trace 50 is insufficient and the connection is not firm enough, and it is easy to crack during the normal use of the battery cell 100. However, if the penetration depth of the welding trace 50 is too large, it will cause welding deformation, stress concentration, etc., and it is also easy to cause the first wall portion 11 to be burned through and the battery cell 100 to be scrapped. Therefore, the first wall portion 11 can be limited to be equal to 0.2 mm, or any value greater than 0.2 and less than H, where H is the thickness dimension of the first wall portion 11.

[0151] This can reduce the probability of the battery cell 100 being scrapped during welding, and at the same time can reduce the probability of the battery cell 100 being easily cracked during normal use, and improve the reliability of the battery cell 100.

[0152] In some embodiments, 0.2 mm ≤ L ≤ 0.9 mm, that is, the penetration depth L of the welding trace 50 can be any point value among 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or the range value between any two of them.

[0153] This can further reduce the probability of the battery cell 100 being scrapped during welding, and at the same time can reduce the probability of the battery cell 100 being easily cracked during normal use, and improve the reliability of the battery cell 100.

[0154] In some embodiments, the thickness dimension of the first wall portion 11 is H, satisfying 1.5 mm ≤ H ≤ 2.5 mm.

[0155] H can be any point value among 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm or the range value between any two of them.

[0156] By limiting the thickness dimension of the first wall portion 11, the space for accommodating the electrode sheets can be increased to a certain extent. Consequently, more electrode sheets can be accommodated within the housing of the battery cell, enhancing the energy density of the battery cell. At the same time, the strength of the first wall portion 11 can be improved to a certain extent, reducing the deformation amount of the first wall portion 11. Furthermore, the pulling force on the welding mark 50 can be reduced, thereby enhancing the reliability of the overall structure.

[0157] As Figures 7 - 10 shown, in some embodiments, the welding mark 50 includes a second mark segment 52 and two relatively arranged first mark segments 51. The extending direction of the second mark segment 52 is perpendicular to the first direction F1, and both ends of the second mark segment 52 are respectively connected to the two first mark segments 51.

[0158] The welding mark 50 further includes a second mark segment 52. The extending direction of the second mark segment 52 is perpendicular to the first direction F1. The connection between the second mark segment 52 and the two first mark segments 51 can form a more secure welding node, improving the strength of the overall connection.

[0159] As Figures 8 - 10 shown, in some embodiments, there are two second mark segments 52. The two second mark segments 52 are arranged oppositely along the first direction F1, and both ends of each second mark segment 52 are respectively connected to the two first mark segments 51.

[0160] The first mark segment 51 and the second mark segment 52 enclose a complete ring shape, which matches the shape of the pressure relief component 40. Thereby, the outer periphery of the pressure relief component 40 is welded to the first wall portion 11, improving the reliability of the connection.

[0161] As Figures 8 - 10 shown, in some embodiments, the first mark segment 51 is an arc segment.

[0162] The arc-shaped first mark segment 51 of the arc segment can better adapt to the curvature of the pressure relief component, providing a smoother and more continuous connection. The arc shape helps to more evenly distribute the welding stress, reducing stress concentration points, reducing the risk of stress concentration and cracks, and improving reliability.

[0163] In some embodiments, the welding mark 50 includes two first mark segments 51. The ends of the two first mark segments 51 are connected to each other, and a circle can be formed.

[0164] As Figures 11 - 14As shown, in some embodiments, along the thickness direction of the first wall portion 11, the first wall portion 11 has a first surface 11a and a second surface 11b that are oppositely arranged. The first wall portion 11 is provided with a receiving groove 112 that is recessed from the first surface 11a towards the second surface 11b. A pressure relief hole 111 is provided at the bottom of the receiving groove 112. The pressure relief component 40 is at least partially located in the receiving groove 112 and is welded to the groove wall of the receiving groove 112 to form a welding mark 50.

[0165] The first wall portion 11 is provided with a receiving groove 112. The receiving groove 112 provides a specific space for the pressure relief component 40, enabling it to be arranged within the first wall portion 11, that is, providing additional space without increasing the external dimensions of the battery cell 100. A pressure relief hole 111 is provided at the bottom of the receiving groove 112. The pressure relief component 40 is at least partially located within the receiving groove 112. When the internal pressure of the battery cell 100 reaches the threshold, the pressure relief component 40 opens the pressure relief hole 111 to discharge the discharge medium inside the battery cell 100, achieving pressure relief. The pressure relief component 40 is connected to the groove wall of the receiving groove 112 by welding, ensuring a firm fixation between the pressure relief component 40 and the first wall portion 11, and at the same time improving the sealing performance of the overall structure.

[0166] As Figures 11 - 14 shown, in some embodiments, the receiving groove 112 includes multiple levels of grooves arranged in sequence from the first surface 11a towards the second surface 11b. In two adjacent levels of grooves, the level of groove farther from the first surface 11a is arranged on the groove bottom surface of the level of groove closer to the first surface 11a. The groove bottom surface of the level of groove that is farthest from the first surface 11a among the multiple levels of grooves has a pressure relief hole 111. The pressure relief component 40 is arranged in one of the levels of grooves among the multiple levels of grooves and is welded to the side wall surface of the level of groove.

[0167] The receiving groove 112 is a stepped groove. The receiving groove 112 can be a two-level groove, a three-level groove, a four-level groove, a five-level groove, etc. Along the direction from the first surface 11a to the second surface 11a, the groove width of each level of groove gradually decreases. As Figure 14 shown, taking the groove section as a two-level groove as an example, the two-level grooves are respectively the first-level groove and the second-level groove. During processing, a second-level groove with a larger width can be first processed on the first surface 11a, and then a first-level groove with a slightly smaller width can be processed on the groove bottom surface of the second-level groove.

[0168] The first-level groove is the level of groove that is farthest from the first surface 11a in the groove section. The groove bottom surface of the first-level groove has a pressure relief hole 111. The pressure relief component 40 can be installed in the first-level groove. The first-level groove can play a role in positioning the pressure relief component 40, enabling the pressure relief component 40 to be properly supported and fixed, and thus facilitating subsequent welding. The pressure relief component 40 is welded to the side wall surface of the first-level groove, improving the stability of the pressure relief component 40, and enhancing the sealing performance and the integrity of the overall structure at the connection between the first wall portion 11 and the pressure relief component 40.

[0169] The second-level groove can provide a certain space for the pressure relief of the pressure relief component 40, facilitating the partial flipping of the pressure relief component 40 after blasting. A patch 60 or the like can also be provided at the second-level groove.

[0170] In some embodiments, the pressure relief component 40 is provided with a predetermined pressure relief area 401 and a scoring groove 41. The predetermined pressure relief area 401 has a predetermined opening boundary, and the predetermined opening boundary is surrounded by the outer edge of the positive projection of at least a part of the scoring groove 41 in the second direction F2; or the predetermined opening boundary is surrounded by the connection lines between multiple ends of the scoring groove 41; or the predetermined opening boundary is jointly surrounded by the connection lines between multiple ends of the scoring groove 41 and the outer edge of the positive projection of at least a part of the scoring groove 41 in the second direction F2. The second direction F2 is the thickness direction of the first wall portion 11, and the second direction F2 is perpendicular to the first direction F1.

[0171] As Figure 16 shown, in some embodiments, the scoring groove 41 includes two relatively arranged first arc segments 411 and two parallel first straight segments 412. The two ends of each first straight segment 412 are respectively connected to the two first arc segments 411, and the two first straight segments 412 and the two first arc segments 411 form a closed ring structure; in the second direction F2, the outer edge of the positive projection of the ring structure forms the predetermined opening boundary of the predetermined pressure relief area 401, that is, the predetermined opening boundary is surrounded by the outer edge of the positive projection of the scoring groove 40 in the second direction F2.

[0172] As Figure 17 shown, in some embodiments, the scoring groove 41 includes a second straight segment 413 and four third straight segments 414. The two ends of the second straight segment 413 are respectively connected to two third straight segments 414 arranged at a preset angle; in the second direction F2, an arc segment 415 centered on the vertex of the preset angle is defined between the free ends of the positive projections of the two third straight segments 414 at the same end of the second straight segment 413, and a fourth straight segment 416 is defined between the free ends of the positive projections of the two third straight segments 414 on the same side of the second straight segment 413. The two arc segments 415 and the two fourth straight segments 416 jointly form the predetermined opening boundary of the predetermined pressure relief area 401, that is, the predetermined opening boundary is surrounded by the connection lines between multiple ends of the scoring groove 40.

[0173] As Figure 18As shown, in some embodiments, the scoring groove 41 includes a fifth straight segment 417 and two sixth straight segments 418. The fifth straight segment 417 is located between the two sixth straight segments 418, and the end portions of the fifth straight segment 417 are respectively connected to the middle portions of the corresponding sixth straight segments 418. The end portions of the two sixth straight segments 418 on the same side of the fifth straight segment 417 define a seventh straight segment 419. The outer edge of the orthographic projection of the seventh straight segment 419 and the sixth straight segment 418 in the second direction F2 constitutes the predetermined opening boundary of the predetermined pressure relief area 401, that is, the predetermined opening boundary is jointly surrounded by the connection lines between the multiple end portions of the scoring groove 40 and the outer edge of the orthographic projection of a part of the scoring groove 40 in the second direction F2.

[0174] Of course, flipping notches 419 can be provided at the seventh straight segment 419 of the scoring groove 41, and thus two flipping notches 419 are correspondingly provided. The two flipping notches 419 are located on both sides of the fifth straight segment 417. The provision of the flipping notches 419 is beneficial for the pressure relief component 40 to relieve pressure along the predetermined opening boundary and ensure the effectiveness of the pressure relief area.

[0175] By adopting the scoring groove 41 with the above structure, it is beneficial for the rapid pressure relief of the pressure relief component 40.

[0176] As Figure 3 and Figure 4 shown, in some examples, the outer shell 10 includes: a housing 101 and an end cover 102. At least one side of the housing 101 has an opening. The end cover 102 is connected to the housing 101 and is used to close the opening. The first wall portion 11 is formed on the housing 101.

[0177] The housing 101 can be a hollow structure with an opening formed at one end, or the housing 101 can be a hollow structure with openings formed at opposite ends. The housing 101 can be of various shapes, such as a prismatic shape, etc.

[0178] The end cover 102 is a component that closes the opening of the housing 101 to isolate the internal environment of the battery cell 100 from the external environment. The end cover 102 and the housing 101 jointly define a receiving space for accommodating the electrode assembly 20, the electrolyte, and other components. The shape of the end cover 102 can be adapted to the shape of the outer shell 10. For example, when the housing 101 is a cuboid structure, the end cover 102 is a rectangular plate-like structure adapted to the outer shell 10. Again, when the housing 101 is a cylindrical structure, the end cover 102 is a circular plate-like structure adapted to the housing 101. The material of the end cover 102 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cover 102 and the housing 101 can be the same or different.

[0179] In an embodiment where the housing 101 has an opening at one end, one end cap 102 can be correspondingly provided. In an embodiment where the housing 101 has openings at opposite ends, two end caps 102 can be correspondingly provided. The two end caps 102 respectively close the two openings of the housing 101, and the two end caps 102 and the housing 101 together define a receiving space.

[0180] The housing 101 has a first wall portion 11 and a second wall portion 12. The pressure relief component 40 is provided on the housing 101. The pressure relief component 40 can be integrally formed with the housing 101 or separately provided from the housing 101. By providing the pressure relief component 40 on the housing 101, the structure of the end cap 102 can be simplified, and at the same time, it is convenient to shorten the distance between the pressure relief component 40 and the main body portion of the electrode assembly 20. Furthermore, the path for the discharged medium to flow to the pressure relief component 40 during pressure relief can be shortened, the time for the discharged medium to reach the pressure relief component 40 can be shortened, the pressure relief timeliness of the battery cell 100 is improved, and thus the reliability of the battery cell 100 is effectively improved.

[0181] In some embodiments, the first wall portion 11 is disposed opposite to the end cap 102. That is to say, the pressure relief component 40 is installed at a position opposite to the end cap 102. Thereby, it is convenient to shorten the distance between the pressure relief component 40 and the main body portion of the electrode assembly 20. Furthermore, the path for the discharged medium to flow to the pressure relief component 40 during pressure relief can be shortened, the time for the discharged medium to reach the pressure relief component 40 can be shortened, the pressure relief timeliness of the battery cell 100 is improved, and thus the reliability of the battery cell 100 is effectively improved.

[0182] In some embodiments, both opposite sides of the housing 101 have openings, and the two end caps 102 are used to close the corresponding openings.

[0183] In an embodiment where the housing 101 has openings at opposite ends, two end caps 102 can be correspondingly provided. The two end caps 102 respectively close the two openings of the housing 101, and the two end caps 102 and the housing 101 together define a receiving space. The first wall portion 11 is located on the housing 101, and the pressure relief component 40 is located between the two openings. Each end cap 102 can be provided with an electrical connection portion 30. By providing two openings on the housing 101, it is convenient for the housing 101 to be manufactured and formed, and at the same time, it is convenient for the electrode assembly 20 to lead out the tabs from both ends. Furthermore, it is convenient to arrange the two electrical connection portions 30 separately, reducing the risk of short circuit of the battery cell 100.

[0184] In some embodiments, the end cap 102 is provided with an electrical connection portion 30. The electrical connection portion 30 is electrically connected to the positive electrode plate 21, or the electrical connection portion 30 is electrically connected to the negative electrode plate 22. Thereby, the electric energy of the battery cell 100 can be input or output.

[0185] In some embodiments, please refer to Figure 15 ,Figure 15 Schematic diagram of the connection between the end cap 102 and the electrical connection portion 30 provided in some embodiments of the present application. The end cap 102 is provided with an extraction hole. The electrical connection portion 30 includes a terminal body 31, a first limiting portion 32, and a second limiting portion 33. The terminal body 31 connects the first limiting portion 32 and the second limiting portion 33. The terminal body 31 is disposed through the extraction hole. Along the second direction F2, the first limiting portion 32 is located on the side of the end cap 102 facing away from the electrode assembly 20, and the second limiting portion 33 is located on the side of the end cap 102 facing the electrode assembly 20.

[0186] The first limiting portion 32 and the second limiting portion 33 have a limiting function. The first limiting portion 32 and the second limiting portion 33 are respectively connected to the ends of the terminal body 31. The first limiting portion 32 and the second limiting portion 33 cooperate to limit the terminal body 31 from being disengaged from the lead-out hole. Along the second direction F2, the projected area of the first limiting portion 32 and the projected area of the second limiting portion 33 are both larger than the projected area of the terminal body 31. The projected area of the first limiting portion 32 may be larger than the projected area of the second limiting portion 33, or the projected area of the second limiting portion 33 may be larger than the projected area of the first limiting portion 32. The first limiting portion 32, the second limiting portion 33, and the terminal body 31 may be integrally formed, or one of the first limiting portion 32 and the second limiting portion 33 may be integrally formed with the terminal body 31, while the other is separately provided and connected to the terminal body 31.

[0187] As an example, the battery cell 10 may also include a first insulating member 6 and a second insulating member 7, the first insulating member 6 being at least partially arranged between the electrical connection part 30 and the end cover 102 to insulate and isolate the electrical connection part 30 and the end cover 102, and the second insulating member 7 being arranged on the side of the end cover 102 facing the electrode assembly 20 to insulate and isolate the electrode assembly 20 and the end cover 102.

[0188] In this embodiment, the electrical connection portion 30 can be installed on the end cover 102 by riveting, which has low installation difficulty and better economy.

[0189] like Figure 3 As shown, the first wall portion 11 is used to support the electrode assembly 20 , and the first wall portion 11 is located below the electrode assembly 20 .

[0190] Therefore, the pressure relief component 40 can be arranged at the bottom of the battery cell 100, and an exhaust channel can be provided at the bottom of the battery cell 100. The exhaust channel and the pressure relief component 40 can be connected, so that when the battery cell 100 has thermal runaway, the high-temperature and high-pressure flue gas can be discharged into the exhaust channel through the pressure relief component 40 at the bottom, and then discharged to the outside.

[0191] In some embodiments, the electrode assembly 20 is a laminated structure, and the electrode assembly 20 includes a plurality of positive electrode sheets 21 and a plurality of negative electrode sheets 22 , and the plurality of positive electrode sheets 21 and the plurality of negative electrode sheets 22 are stacked along a first direction F1 .

[0192] As an example, the positive electrode sheets 21 and the negative electrode sheets 22 in the electrode assembly 20 are alternately arranged along the first direction F1 , and a separator is provided between the positive electrode sheets 21 and the negative electrode sheets 22 .

[0193] In this embodiment, the electrode assembly 20 is a laminated electrode assembly, which has a more compact structure and a stronger anti-extrusion capability.

[0194] In some embodiments, the number of negative electrode sheets 22 is greater than the number of positive electrode sheets 21 , and one positive electrode sheet 21 is disposed between two adjacent negative electrode sheets 22 .

[0195] As an example, there is one more negative electrode sheet 22 than positive electrode sheet 21 .

[0196] In some embodiments, each negative electrode plate 22 is provided with a negative electrode tab; and / or each positive electrode plate 21 is provided with a positive electrode tab.

[0197] The battery 1000 according to the second aspect embodiment of the present application includes the battery cell 100 according to the above-mentioned first aspect embodiment of the present application. By adopting the above-mentioned battery cell 100, the damage and cracking in the overlapping area 53 due to the expansion of the electrode assembly 20 can be reduced, and the risk of cracking and leakage at the connection between the pressure relief component 40 and the first wall portion 11 can be reduced to a certain extent, thereby improving the reliability of the battery cell 100.

[0198] According to an embodiment of the third aspect of the present application, an electrical device includes the battery 1000 according to the embodiment of the second aspect of the present application, and the battery 1000 is used to provide power to the electrical device. Thus, by using the battery 1000, the safety and reliability of the electrical device can be improved.

[0199] Alternatively, as Figure 1 As shown, when battery 1000 is used in a vehicle, it can be installed at the bottom, front, or rear of the vehicle. Battery 1000 can be used to power the vehicle, for example, as an operating power source for the vehicle. The vehicle may also include a controller and a motor. The controller is used to control battery 1000 to power the motor, for example, to meet the vehicle's starting, navigation, and driving needs.

[0200] A battery 1000 and a vehicle having the same according to a specific embodiment of the present application will be described below with reference to the accompanying drawings.

[0201] like Figure 1As shown, the battery 1000 is provided at the bottom of the vehicle, and as Figure 2 shown, the battery 1000 includes a plurality of battery cells 100, as Figure 3 shown, each battery cell 100 includes a housing 10 and an electrode assembly 20. An electrical connection portion 30 and a pressure relief component 40 are provided on the housing 10, and the electrical connection portion 30 and the pressure relief component 40 are located on different sides of the housing 10; the electrode assembly 20 is arranged inside the housing 10.

[0202] The electrode assembly 20 has a flat region 23, and at least a part of the positive electrode plate 21, at least a part of the negative electrode plate 22, and at least a part of the separator 25 are stacked in the flat region 23 along the first direction F1.

[0203] As Figure 3 shown, the housing 10 is generally in the shape of a quadrangular prism, with a simple structure and easy to mold. The housing 10 has a first wall portion 11, and the first wall portion 11 is located on one side of the electrode assembly 20 in the second direction F2. As Figure 11 shown, a pressure relief hole 111 is provided on the first wall portion 11, and the pressure relief component 40 can be installed at the pressure relief hole 111 of the first wall portion 11 by welding. As Figure 4 shown, the pressure relief component 40 is a component independent of the housing 10. The pressure relief component 40 and the housing 10 can be produced separately and then assembled. A patch 60 can also be provided on the outer side of the pressure relief component 40, and the patch 60 cooperates with the housing 10 to protect the pressure relief component 40.

[0204] As Figure 7 and Figure 10 shown, the pressure relief component 40 is welded to the first wall portion 11 to form a welding mark 50. The welding mark 50 includes two first trace segments 51 and two second trace segments 52. The first trace segment 51 is an arc segment, and the second trace segment 52 is a straight segment. The tangent at any point on the first trace segment 51 is not perpendicular to the first direction F1, and the extending direction of the first trace segment 51 is perpendicular to the first direction F1.

[0205] As Figure 10 shown, the welding mark 50 has an overlapping region 53, and the overlapping region 53 is located on the first trace segment 51. When the pressure relief component 40 is welded to the first wall portion 11, during the welding process, the welding mark 50 also has a first end 501 and a second end 502. The first end 501 and the second end 502 are both spaced from the overlapping region 53, and the first end 501 and the second end 502 are both located on the first wall portion 11.

[0206] 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, Comprising: An electrode assembly, including at least one positive electrode tab, at least one negative electrode tab, and at least one separator. The positive electrode tab, the negative electrode tab, and the separator are stacked to form a flat region, and at least a part of the positive electrode tab, at least a part of the negative electrode tab, and at least a part of the separator are stacked in the flat region along a first direction; A housing for accommodating the electrode assembly, the housing including a first wall portion; A pressure relief component, the pressure relief component is installed on the first wall portion, and the pressure relief component is configured to be able to release the pressure inside the battery cell; the pressure relief component is welded to the first wall portion to form a welding mark, and the welding mark includes a first mark segment, and the first mark segment extends along the first direction; Wherein, the welding mark has an overlapping region, and the overlapping region is located in the first mark segment.

2. The battery cell according to claim 1, wherein The welding mark of the pressure relief component and the first wall portion has a first end portion and a second end portion, and both the first end portion and the second end portion are arranged in the overlapping region.

3. The battery cell according to claim 1, wherein The welding mark of the pressure relief component and the first wall portion has a first end portion and a second end portion, and the first end portion is spaced from the overlapping region; and / or the second end portion is spaced from the overlapping region.

4. The battery cell according to claim 3, wherein The spacing distance between the first end portion and the overlapping region is greater than or equal to 0.5 mm, and / or the spacing distance between the second end portion and the overlapping region is greater than or equal to 0.5 mm.

5. The battery cell according to claim 3, characterized in that, The first end portion is only located on the first wall portion, and / or the second end portion is only located on the first wall portion.

6. The battery cell according to claim 3, wherein The penetration depth of the first end portion is less than the penetration depth of the overlapping region; and / or the penetration depth of the second end portion is less than the penetration depth of the overlapping region.

7. The battery cell according to claim 1, characterized in that, The penetration depth of the welding mark is L, and the thickness dimension of the first wall portion is H, satisfying: 0.2 mm ≤ L < H.

8. The battery cell according to claim 7, characterized in that, 0.2 mm ≤ L ≤ 0.9 mm.

9. The battery cell according to claim 7, wherein The thickness dimension of the first wall portion is H, satisfying 1.5 mm ≤ H ≤ 2.5 mm.

10. The battery cell according to claim 1, characterized in that, The welding mark includes a second mark segment and two relatively arranged first mark segments, the extending direction of the second mark segment is perpendicular to the first direction, and both ends of the second mark segment are respectively connected to the end portions of each first mark segment.

11. The battery cell according to claim 10, wherein, There are two second mark segments, and the two second mark segments are arranged oppositely along the first direction, and both ends of each second mark segment are respectively connected to the two first mark segments.

12. The battery cell according to claim 1, characterized in that, The first mark segment is an arc segment.

13. The battery cell according to any one of claims 1-12, wherein Along the thickness direction of the first wall portion, the first wall portion has a first surface and a second surface arranged oppositely, the first wall portion is provided with a receiving groove recessed from the first surface towards the direction close to the second surface, a pressure relief hole is provided at the bottom of the receiving groove, and at least a part of the pressure relief component is located in the receiving groove and is welded to the groove wall of the receiving groove to form the welding mark.

14. The battery cell according to claim 13, wherein The accommodating groove includes a multi-stage groove arranged in sequence along the first surface toward the second surface. In two adjacent grooves, the first-stage groove away from the first surface is arranged on the groove bottom surface of the first-stage groove close to the first surface. The groove bottom surface of the first-stage groove farthest from the first surface in the multi-stage groove has the pressure relief hole. The pressure relief component is arranged in the first-stage groove in the multi-stage groove and welded to the side wall surface of the first-stage groove.

15. The battery cell according to claim 1, characterized in that The pressure relief component is provided with a predetermined pressure relief area and a notched groove, the predetermined pressure relief area has a predetermined opening boundary, the predetermined opening boundary is surrounded by the outer edge of the positive projection of at least a portion of the notched groove in the second direction; or the predetermined opening boundary is surrounded by the connecting line between multiple ends of the notched groove; or the predetermined opening boundary is jointly surrounded by the connecting line between multiple ends of the notched groove and the outer edge of the positive projection of at least a portion of the notched groove in the second direction, and the second direction is the thickness direction of the first wall portion and is perpendicular to the first direction.

16. The battery cell according to claim 1, wherein The housing includes a shell and an end cover. At least one side of the shell has an opening. The end cover is connected to the shell and is used to close the opening. The first wall portion is formed on the shell.

17. The battery cell according to claim 16, wherein, The first wall portion is arranged opposite to the end cover.

18. The battery cell according to claim 16, wherein Two opposite sides of the shell are each provided with an opening, and the two end covers are used to close the openings on the corresponding sides.

19. The battery cell according to claim 16, wherein, The end cover is provided with an electrical connection portion, and the electrical connection portion is electrically connected to the positive electrode plate, or the electrical connection portion is electrically connected to the negative electrode plate.

20. The battery cell according to claim 19, characterized in that The end cover is provided with a lead-out hole, and the electrical connection part includes a terminal body, a first limiting part and a second limiting part. The terminal body connects the first limiting part and the second limiting part, and the terminal body is passed through the lead-out hole. Along the first direction, the first limiting part is located on the side of the end cover away from the electrode assembly, and the second limiting part is located on the side of the end cover facing the electrode assembly.

21. The battery cell according to claim 1, wherein The first wall portion is used to support the electrode assembly and is located below the electrode assembly.

22. The battery cell according to claim 1, characterized in that, The electrode assembly is a laminated structure, comprising a plurality of positive electrode sheets and a plurality of negative electrode sheets, wherein the plurality of positive electrode sheets and the plurality of negative electrode sheets are stacked along the first direction.

23. The battery cell according to claim 22, wherein, The number of the negative electrode sheets is greater than the number of the positive electrode sheets, and one positive electrode sheet is arranged between two adjacent negative electrode sheets.

24. The battery cell according to claim 22, wherein, Each of the negative electrode plates is provided with a negative electrode tab; and / or each of the positive electrode plates is provided with a positive electrode tab.

25. A battery, characterized in that, The invention comprises a battery cell according to any one of claims 1 to 24.

26. An electrical device, characterized in that, The battery according to claim 25 is used to provide electrical energy to the electrical device.

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