Battery monomer, battery and electric device

Abstract

The utility model discloses a battery monomer, a battery and a power utilization device, and the battery monomer comprises a shell which is provided with an opening in at least one end along a first direction and comprises two first walls; the end cover seals the opening; the first wall and the end cover are welded to form a first connecting part; the first area of the first wall is located on the side, close to the first connecting part, of the second area, the thickness of the first area is larger than that of the second area, the thickness difference value is t, and t is smaller than or equal to 0.6 mm; and when the battery monomer is in a 0% charge state, the total thickness of the straight areas of the N1 electrode assemblies in the second direction is X1, the distance between the inner surfaces of the second areas of the two first walls is X2, and X2-X1 is greater than or equal to 0.03 mm and less than or equal to 0.5 mm. According to the technical scheme provided by the embodiment of the invention, the probability of cracking and damage of the first connecting part and the vicinity thereof can be reduced, the strength of the first connecting part and the vicinity thereof can be improved, the reliability of the battery monomer can be improved, the shell can be conveniently manufactured and formed, and the energy density of the battery monomer can be ensured to a certain extent.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0003] During the use of the battery cell, the welds between the shell and the end cover of the outer shell are easily damaged and cracked due to stress, which reduces the reliability of the battery cell. Utility Model Content

[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 damage to the welding points between the shell and the end cover during the use of the battery.

[0005] In the first aspect, the present application provides a battery cell, comprising: a shell having an opening at at least one end along a first direction, the shell comprising two first walls, the two first walls being arranged opposite to each other along a second direction, the first direction intersecting the second direction; an end cover closing the opening, the first wall and the end cover being welded to form a first connection portion; the first wall comprising a first area and a second area arranged along the first direction, the first area being located on a side of the second area close to the first connection portion, the thickness of the first area being greater than the thickness of the second area; the difference between the thickness of the first area and the thickness of the second area being t, satisfying: t≤0.6mm; N1 electrode assemblies, accommodated in the shell, each electrode assembly comprising a flat area, when the battery cell is in a 0% state of charge, the total thickness of the flat areas of the N1 electrode assemblies in the second direction is X1, the distance between the inner surfaces of the second areas of the two first walls is X2, satisfying: 0.03mm≤X2-X1≤0.5mm.

[0006] In the technical solution of the embodiment of the present application, by thickening the first area of ​​the first wall and limiting the thickening thickness difference t to less than or equal to 0.6mm, and at the same time limiting the difference between the distance X1 between the inner surfaces of the two second areas and the total thickness X2 of the electrode assembly to between 0.03mm-0.5mm when the battery cell is in a 0% charge state, the probability of cracking and damage of the first connection part and its vicinity can be reduced, the strength of the first connection part and its vicinity can be improved, the reliability of the battery cell can be improved, the manufacturing and molding of the shell can be facilitated, and the energy density of the battery cell can be guaranteed to a certain extent.

[0007] In some embodiments, 0.05 mm ≤ X2 - X1 ≤ 0.3 mm. In the above technical solution, the probability of cracking and damage at the first connection portion and its vicinity can be further reduced, the strength of the first connection portion and its vicinity can be improved, the reliability of the battery cell can be improved, and the energy density of the battery cell can be increased.

[0008] In some embodiments, 20 mm ≤ X2 ≤ 85 mm. In the above technical solution, the internal space of the housing is increased to a certain extent, which is convenient for accommodating a certain number of electrode assemblies of a certain size. In addition, within a battery cell that meets the above dimensions, the manufacturing and molding of the housing is facilitated, the strength of the first region is improved, the probability of cracking and damage at the first connection portion and its vicinity is reduced, and the reliability of the battery cell is improved.

[0009] In some embodiments, 19.5 mm ≤ X1 ≤ 84.97 mm. In the above technical solution, the energy density of the battery cell can be guaranteed to a certain extent. Furthermore, within a battery cell that meets the above dimensions, the manufacturing and molding of the housing is facilitated, the strength of the first region is improved, the probability of cracking and damage at the first connection portion and its vicinity is reduced, and the reliability of the battery cell is improved.

[0010] In some embodiments, each of the electrode assemblies includes at least one positive electrode sheet, at least one negative electrode sheet, and at least one separator, wherein the positive electrode sheet, the negative electrode sheet, and the separator are stacked to form a flat area, and at least a portion of the positive electrode sheet, at least a portion of the negative electrode sheet, and at least a portion of the separator are stacked along the second direction in the flat area; the number of layers of the positive electrode sheets stacked in the flat area of ​​each electrode assembly is N2, and the flat area has an outer surface perpendicular to the first direction, and the area of ​​the outer surface is S, N1≥1, N2≥1, N1*N2≤500, and S≤80000mm 2 In the above technical solution, the expansion of the electrode assembly can be reduced during the charge and discharge process of the battery cell, thereby reducing the probability of cracking and damage at the first connecting portion and its vicinity, thereby improving the reliability of the battery cell.

[0011] In some embodiments, the first region includes a first portion and a second portion arranged along the first direction, the second portion connects the first portion and the second region, the thickness of the first portion is the same as the thickness of the first region, and the thickness of the second portion decreases along the direction from the end cap to the electrode assembly. In the above technical solution,

[0012] In some embodiments, along the first direction, the height dimension of the first portion is H1, which satisfies the following conditions: 0.7 mm < H1 ≤ 10 mm. In the above technical solution, the structural strength of the first connection portion can be maintained to a certain extent while reducing the space occupied by the electrode assembly, thereby preventing a reduction in the energy density of the battery cell to a certain extent.

[0013] In some embodiments, along the first direction, the height dimension of the first region is H2, and the height dimension of the first portion is H1, satisfying the following conditions: H2>H1, 1.5mm

[0014] In some embodiments, the second zone has a first inner surface facing the interior space of the shell and a first outer surface facing away from the interior of the shell, and the first zone includes a first protrusion protruding from the first inner surface. In the above technical solution, the outer surface of the shell is flat, which facilitates the stacking and arrangement of multiple battery cells in a direction perpendicular to the first wall.

[0015] In some embodiments, the first region includes a second protrusion protruding from the first outer surface. In the above technical solution, the thickened area of ​​the first wall does not occupy the internal space of the housing, which facilitates the assembly of the electrode assembly into the housing, reduces the probability of interference between the electrode assembly and the first region during assembly, and increases the capacity of the electrode assembly to a certain extent, thereby improving the energy density of the battery cell.

[0016] In some embodiments, the positive electrode sheet includes a positive electrode main region and a positive electrode tab protruding from the positive electrode main region, and the negative electrode sheet includes a negative electrode main region and a negative electrode tab protruding from the negative electrode main region. In a projection plane perpendicular to the second direction, the orthographic projection of the positive electrode sheet does not overlap with the orthographic projection of the first region; and / or, in a projection plane perpendicular to the second direction, the orthographic projection of the negative electrode main region does not overlap with the orthographic projection of the first region. In the above technical solution, the housing can provide a larger expansion space for the electrode assembly, reducing the risk of the electrode assembly expanding and directly applying an expansion force to the first protrusion, reducing the deformation of the first wall, and further reducing the risk of fatigue cracking in the area of ​​the first wall near the first connection portion.

[0017] ​In some embodiments, the battery cell further includes an electrical connection portion, the electrical connection portion being disposed on the end cap and electrically connected to the electrode assembly; the end cap is provided with an extraction hole, the electrical connection portion including a terminal body, a first limiting portion, and a second limiting portion, the terminal body connecting the first limiting portion and the second limiting portion, the terminal body being passed through the extraction hole, and along the first direction, the first limiting portion being located on the side of the end cap facing away from the electrode assembly, and the second limiting portion being located on the side of the end cap facing the electrode assembly. In the above technical solution, the electrical connection portion can be mounted to the end cap by riveting, which reduces installation difficulty and provides better economic efficiency.

[0018] In some embodiments, 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 second direction. In the above technical solution, the laminated electrode assembly has a more compact structure and greater compressive resistance.

[0019] In some embodiments, along the third direction, the first region is larger than the positive electrode tab and / or the negative electrode tab, and the first direction, the second direction, and the third direction are perpendicular to each other. In the above technical solution, along the third direction, the first region is larger than the positive electrode tab and / or the negative electrode tab, making the first region larger in the third direction. This increases the strength of the first wall in more areas along the third direction, further reducing the risk of fatigue cracking in the area of ​​the first wall near the first connection portion.

[0020] In some embodiments, the electrode assembly has a wound structure and further comprises a corner region. The corner region is provided at at least one end of the straight region along the third direction. At least a portion of the outer surface of the corner region is a circular arc surface. The first direction, the second direction, and the third direction are not coplanar and intersect with each other. In the above technical solution, for the wound electrode assembly, the straight region expands more in the second direction. Because the first region strengthens the area of ​​the first wall near the first connection portion, the risk of fatigue cracking of the first wall near the first connection portion due to expansion of the electrode assembly can be effectively reduced.

[0021] In a second aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0022] In a third aspect, the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0023] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0025] Figure 1 is a schematic diagram of an electrical device in the related art;

[0026] Figure 2 A schematic diagram of a battery in the related art;

[0027] Figure 3 A schematic diagram of a battery provided in some embodiments of the present application;

[0028] Figure 4 Schematic diagrams of batteries provided in some other embodiments of the present application;

[0029] Figure 5 A schematic diagram of an electrode assembly provided in some embodiments of the present application;

[0030] Figure 6 Schematic diagrams of electrode assemblies provided in other embodiments of the present application;

[0031] Figure 7 A cross-sectional view of a battery cell at 0% state of charge provided in some embodiments of the present application;

[0032] Figure 8 for Figure 7 The middle circle shows an enlarged view of A in some examples, wherein the first connecting portion is hidden;

[0033] Figure 9 for Figure 7 The middle circle shows an enlarged view of A in some other examples, wherein the first connecting portion is hidden;

[0034] Figure 10 Schematic diagram of the connection between the end cap and the electrical connection part provided in some embodiments of the present application.

[0035] Reference numerals:

[0036] Battery 1000, vehicle 2000, battery cell 100, housing 200, first shell 201, second shell 202,

[0037] Housing 10, shell 101, end cover 102, first wall 11, first area 111, first portion 111a, second portion 111b, first protrusion 1111, second protrusion 1112, second area 112, first inner surface 1121, first outer surface 1122, second wall 12,

[0038] Electrode assembly 20, positive electrode sheet 21, negative electrode sheet 22, straight area 23, corner area 24, separator 25,

[0039] Electrical connection portion 30, terminal body 31, first limiting portion 32, second limiting portion 33,

[0040] Pressure relief component 40,

[0041] First connecting portion 51 , first insulating member 6 , second insulating member 7 . DETAILED DESCRIPTION

[0042] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0044] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0045] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0046] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0047] The term "plurality" used in this application refers to two or more (including two).

[0048] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0049] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0050] The battery mentioned in the embodiments of the present application may 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, in parallel or in hybrid through a busbar.

[0051] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0052] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0053] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0054] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0055] The development of battery technology must consider multiple design factors simultaneously, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters.

[0056] Generally, the shell of the battery is formed by welding the shell and the end cap. During the use of the battery cell in charging and discharging, the electrode assembly expands, and the expansion force acts on the shell, which is easy to cause fatigue cracking of the welding part (especially the welding heat affected zone) of the shell and the end cap. In addition, when the battery cell produces gas during charging and discharging or abnormal gas production, the welding part of the shell and the end cap is also easy to break and crack.

[0057] In view of this, the battery cell provided by the embodiments of the present application comprises: a shell having an opening at least at one end in a first direction, the shell comprising two first walls, the two first walls being respectively located on two sides of the electrode assembly in a second direction, the first direction intersecting the second direction; an end cap closing the opening, the first wall and the end cap being welded to form a first connecting part; the first wall comprising a first area and a second area arranged in the first direction, the first area being located on one side of the second area close to the first connecting part, the thickness of the first area being greater than the thickness of the second area; the difference between the thickness of the first area and the thickness of the second area being t, and t≤0.6mm; N1 electrode assemblies accommodated in the shell, each electrode assembly comprising a flat area, the total thickness of the flat areas of the N1 electrode assemblies in the second direction being X1 when the battery cell is in 0% state of charge, the distance between the inner surfaces of the second areas of the two first walls being X2, and 0.03mm≤X2-X1≤0.5mm.

[0058] In such a battery cell, by thickening the first area of the first wall and limiting the difference t between the thickening thickness to be less than or equal to 0.6mm, and at the same time limiting the difference between the distance X1 between the inner surfaces of the two second areas and the total thickness X2 of the electrode assemblies to be between 0.03mm and 0.5mm when the battery cell is in 0% state of charge, the probability of cracking and damage of the first connecting part and its vicinity can be reduced, the strength of the first connecting part and its vicinity can be improved, the reliability of the battery cell can be improved, the manufacturing of the shell is facilitated, and the energy density of the battery cell can be ensured to a certain extent.

[0059] The technical solutions described in the embodiments of the present application are suitable for batteries and electric devices using batteries.

[0060] The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game machine, an electric automobile toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, and an electric planer, etc. The electric device is not specially limited in the embodiments of the present application.

[0061] The following embodiments are described by taking the electric device as a vehicle for example.

[0062] Please refer to Figure 1 , Figure 1 A structural schematic diagram of the vehicle 2000 provided by some embodiments of the present application is shown. The vehicle 2000 is internally provided with the battery 1000, which can be arranged at the bottom, the head, or the tail of the vehicle 2000. The battery 1000 can be used for power supply of the vehicle 2000, for example, the battery 1000 can be used as an operating power supply of the vehicle 2000.

[0063] The vehicle 2000 can further include a controller and a motor, and the controller is used to control the battery 1000 to supply power to the motor, for example, to meet the working power demand of the vehicle 2000 during starting, navigation, and driving.

[0064] In some embodiments of the present application, the battery 1000 can not only be used as an operating power supply of the vehicle 2000, but also be used as a driving power supply of the vehicle 2000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 2000.

[0065] Please refer to Figure 2 , Figure 2 An exploded view of the battery 1000 provided by some embodiments of the present application is shown. The battery 1000 includes a battery monomer 100 and a box body 200, and the box body 200 is used to accommodate the battery monomer 100.

[0066] The housing 200 is a component that houses the battery cells 100 and provides storage space for the battery cells 100. The housing 200 can have various structures. In some embodiments, the housing 200 can include a first shell 201 and a second shell 202, which cover each other to define a storage space for the battery cells 100. The first shell 201 and the second shell 202 can have various shapes, such as a rectangular parallelepiped or a cylinder. The first shell 201 can be a hollow structure with one side open, and the second shell 202 can also be a hollow structure with one side open. The open side of the second shell 202 covers the open side of the first shell 201, forming the housing 200 with storage space. Alternatively, the first shell 201 can be a hollow structure with one side open, and the second shell 202 can be a plate-like structure. The second shell 202 covers the open side of the first shell 201, forming the housing 200 with storage space. As an example, the battery cell 100 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack 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 polygonal battery, and a polygonal battery such as a hexagonal battery, etc. There is no special limitation in this application.

[0067] In the battery 1000, there can be one or more battery cells 100. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 100. Multiple battery cells 100 can be connected in series, parallel, or in a hybrid connection to form a battery module, which is then connected in series, parallel, or in a hybrid connection to form a whole and housed within the housing 200. Alternatively, all battery cells 100 can be directly connected in series, parallel, or in a hybrid connection, and then the whole battery module 100 can be housed within the housing 200.

[0068] Please refer to Figure 3 and Figure 4 , Figure 3 and Figure 4 Schematic diagram of a battery cell 100 provided in some embodiments of the present application. The battery cell 100 may include a housing 10 and an electrode assembly 20.

[0069] The housing 10 is used to house the electrode assembly 20 and other components such as the electrolyte. The housing 10 may be a steel shell, an aluminum shell, a plastic shell (e.g., polypropylene), a composite metal shell (e.g., a copper-aluminum composite shell), or an aluminum-plastic film. For example, the housing 10 may include a shell 101 and an end cap 102.

[0070] The housing 101 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at two opposite ends. The housing 101 may be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, and the like.

[0071] The end cap 102 is a component that closes the opening of the shell 101 to isolate the internal environment of the battery cell 100 from the external environment. The end cap 102 and the shell 101 together define a storage space for accommodating the electrode assembly 20, electrolyte and other components. The end cap 102 can be connected to the shell 101 by welding or rolling to close the opening of the shell 101. The shape of the end cap 102 can be adapted to the shape of the shell 10. For example, the shell 101 is a rectangular parallelepiped structure, and the end cap 102 is a rectangular plate structure adapted to the shell 10. The material of the end cap 102 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0072] In the battery cell 10, there can be one or two end caps 102. In embodiments where the housing 101 is a hollow structure with openings at both ends, two end caps 102 can be 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 storage space. In embodiments where the housing 101 is a hollow structure with an opening at one end, there can be one end cap 102 provided. The end cap 102 closes the opening at one end of the housing 101, and the end cap 102 and the housing 101 together define a storage space.

[0073] 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) are inserted and removed between the positive and negative electrodes. The separator is placed between the positive and negative electrodes to prevent short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0074] In some embodiments, the positive electrode may be a positive electrode sheet 21 . The positive electrode sheet 22 may include a positive electrode current collector and a positive electrode active material region disposed on at least one surface of the positive electrode current collector. The positive electrode active material region has a positive electrode active material.

[0075] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material region is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0076] In some embodiments, the negative electrode may be a negative electrode sheet 22 , which may include a negative electrode current collector and a negative electrode active material region disposed on at least one surface of the negative electrode current collector.

[0077] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material region is provided on either one or both of the two facing surfaces of the negative electrode current collector.

[0078] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0079] In some embodiments, the electrode assembly 20 further includes a separator disposed between the positive electrode and the negative electrode.

[0080] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0081] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0082] In some embodiments, the battery cell 100 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte may be selected based on needs. The electrolyte may be liquid, gel, or solid.

[0083] In some embodiments, the electrode assembly 20 is a wound structure in which the positive electrode sheet, the negative electrode sheet, and the separator are wound into the wound structure.

[0084] In some embodiments, the electrode assembly 20 is a laminated structure.

[0085] As an example, a plurality of positive electrode sheets 21 , a plurality of negative electrode sheets 22 and a plurality of separators 25 may be provided, and the plurality of positive electrode sheets 21 , the plurality of negative electrode sheets 22 and the plurality of separators 25 may be alternately stacked.

[0086] As an example, multiple separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0087] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0088] In some embodiments, the shape of the electrode assembly 20 can be flat or polygonal.

[0089] In some embodiments, the electrode assembly 20 is provided with tabs, which can conduct current from the electrode assembly 20. The tabs include a positive tab and a negative tab.

[0090] The battery cell 100 may further include an electrical connector 30 , which may be disposed on the outer casing 10 . The electrical connector 30 is configured to electrically connect to the tab of the electrode assembly 20 to output electrical energy from the battery cell 10 . The electrical connector 30 and the tab may be directly connected, for example, by direct welding. Alternatively, the electrical connector 30 and the tab may be indirectly connected, for example, through a current collecting member. The current collecting member may be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0091] like Figure 3 and Figure 4 As shown, taking the shell 101 as an example of a hollow structure with an opening at one end, two electrical connection parts 30 can be provided on the end cover 102, and the two electrical connection parts 30 are respectively a positive electrical connection part and a negative electrical connection part, the positive electrical connection part is electrically connected to the positive electrode ear, and the negative electrical connection part is electrically connected to the negative electrode ear.

[0092] like Figure 3 and Figure 4 As shown, the battery cell 100 also has a pressure relief component 40, which is a component for releasing the internal pressure of the battery cell 100. When the internal pressure of the battery cell 100 reaches a threshold, the discharge medium inside the battery cell 100 is discharged through the pressure relief component 40 to achieve the purpose of pressure relief. The threshold design varies according to different design requirements. The threshold may depend on one or more materials of the positive electrode plate 21, the negative electrode plate 22, the electrolyte and the separator 25 in the battery cell 100.

[0093] The pressure relief component 40 has a notch groove, and when the battery cell 100 is depressurized, it can be split along at least a portion of the notch groove, such as Figure 3 As shown, the end cover 102 is provided with a pressure relief component 40; Figure 4 As shown, 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 can be provided separately from the housing 101. For example, the housing 101 includes a second wall 12. The second wall 12 is located on one side of the electrode assembly 20 in the first direction. The thickness direction of the second wall 12 is the first direction. The pressure relief component 40 is provided on the second wall 12. By providing the pressure relief component 40 on the housing 101, the structure of the end cap 102 can be simplified, and the distance between the pressure relief component 40 and the main body of the electrode assembly 20 can be shortened. In addition, the path for the discharge medium to flow to the pressure relief component 40 during pressure relief can be shortened, and the time it takes for the discharge medium to reach the pressure relief component 40 can be shortened, thereby improving the timeliness of pressure relief of the battery cell 100, thereby effectively improving the reliability of the battery cell 100.

[0094] Please refer to Figure 5 and Figure 6 , Figure 5A schematic diagram of an electrode assembly 20 provided in some embodiments of the present application; Figure 6 Schematic diagram of an electrode assembly 20 provided in some other embodiments of the present application. The electrode assembly 20 includes a positive electrode sheet 21 and a negative electrode sheet 22. The positive electrode sheet 21 includes a positive electrode body and a positive electrode tab. The positive electrode tab extends from one end of the positive electrode body. Most of the positive electrode tab is not coated with positive electrode active material, while most of the positive electrode body is coated with positive electrode active material. The negative electrode sheet 22 includes a negative electrode body and a negative electrode tab. The negative electrode tab extends from one end of the negative electrode body. Most of the negative electrode tab is not coated with negative electrode active material, while most of the negative electrode body is coated with negative electrode active material. The positive electrode body and the negative electrode body constitute the main body of the electrode assembly.

[0095] like Figure 5 As shown, the electrode assembly 20 includes a plurality of electrode sheets arranged in a wound manner. The electrode assembly 20 includes a straight region 23 and a corner region 24 connected to ends of the straight region 23 .

[0096] A plurality of electrode sheets arranged in a wound manner, namely, a positive electrode sheet 21 and a negative electrode sheet 22 are stacked and wound around a set axis to form an electrode assembly 20. The straight area 23 refers to the portion of the electrode sheet extending along the plane after winding; the corner area 24 refers to the portion of the electrode sheet extending along the arc surface after winding, for example Figure 5 As shown, the portion between the front side surface and the rear side surface of the electrode assembly 20 is formed as a straight area 23. The extension direction of the electrode piece in the straight area 23 is the length direction of the straight area 23. Figure 5 As shown, in the straight area 23 , the length dimension of the positive electrode plate 21 in the left-right direction is B1 , and the left and right ends of the straight area 23 are corner areas 24 .

[0097] like Figure 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 .

[0098] A plurality of stacked electrodes, for example, at least one positive electrode 21 and at least one negative electrode 22, are stacked to form an electrode assembly 20. The straight region 23 is formed by stacking at least a portion of the positive electrode 21 and the negative electrode 22. Alternatively, the straight region 23 is formed by stacking at least a portion of the positive electrode 21 and the negative electrode 22. The extension direction of the electrode in the straight region 23 is the length direction of the straight region 23. Figure 6 As shown, in the straight area 23 , the length dimension of the positive electrode tab 21 in the left-right direction is B1 .

[0099] Please refer to Figure 7-Figure 9 , Figure 7 A cross-sectional view of a battery cell 100 provided in some embodiments of the present application at a 0% state of charge; Figure 8 and Figure 9 for Figure 7 The middle circle shows an enlarged view of A in some examples.

[0100] Combine Figure 3-Figure 9 As shown, the battery cell 100 according to the embodiment of the present application includes: a shell 101, an end cover 102 and N1 electrode assemblies 20, the shell 101 has an opening at at least one end along the first direction F1, the shell 101 includes two first walls 11, the two first walls 11 are arranged opposite to each other along the second direction F2, and the first direction F1 intersects with the second direction F2; the end cover 102 closes the opening, and the first wall 11 and the end cover 102 are welded to form a first connection portion 51; the first wall 11 includes a first area 111 and a second area 112 arranged along the first direction F1, the first area 111 is located on the side of the second area 112 close to the first connection portion 51, and the thickness of the first area 111 is greater than the thickness of the second area 112; the difference between the thickness of the first area 111 and the thickness of the second area 112 is t, satisfying: t≤0.6mm.

[0101] Each electrode assembly 20 includes a flat area 23. When the battery cell 100 is in a 0% state of charge, the total thickness of the flat areas 23 of N1 electrode assemblies 20 in the second direction F2 is X1, and the distance between the inner surfaces of the second areas 112 of the two first walls 11 is X2, satisfying: 0.03mm≤X2-X1≤0.5mm.

[0102] The shell 101 and the end cover 102 constitute the outer shell of the battery cell 100, that is, the outermost structural component of the battery cell 100. The outer shell accommodates the electrode assembly 20 and electrolyte, etc., wherein the electrode assembly 20 accommodated can be one or more.

[0103] The shell 101 can be a hollow structure with an opening formed at one end, or a hollow structure with openings formed at two opposite ends. The shell 101 can be in various shapes, such as a prism, etc. The prism can be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, etc., and the quadrangular prism can be a cuboid, a cube, etc. The first direction F1 is parallel to the direction of the opening of the shell 101. In the embodiment where the shell 101 is prism-shaped, the first direction F1 can be parallel to the extension direction of the side edges of the shell 101. The second direction F2 is parallel to the thickness direction of the first wall 11. The shell 101 includes two first walls 11, and the first wall 11 can be a rectangular plate-like structure. The first direction F1 and the second direction F2 can be set at an acute angle, a right angle, or an obtuse angle.

[0104] 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 storage space for accommodating the electrode assembly 20, electrolyte, and other components. The shape of the end cap 102 can be adapted to the shape of the housing. For example, if the housing 101 is a rectangular parallelepiped structure, the end cap 102 is a rectangular plate structure that adapts to the housing. The end cap 102 can also be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The end cap 102 and the housing 101 can be made of the same or different materials.

[0105] In embodiments where the housing 101 is open at one end, one end cap 102 may be provided. In embodiments where the housing 101 is open at two opposite ends, two end caps 102 may be provided, each of which seals the two openings of the housing 101. The two end caps 102 and the housing 101 together define a receiving space for accommodating the electrode assembly 20 and electrolyte.

[0106] In an embodiment where the shell 101 forms openings at two opposite ends, two end covers 102 may be provided. The two end covers 102 respectively close the two openings of the shell 101. The two end covers 102 and the shell 101 together define a receiving space for accommodating the electrode assembly 20 and the electrolyte, etc.

[0107] The end cap 102 can be welded to the housing 101. The welding of the end cap 102 and the housing 101 can form a connecting portion, which can extend along the circumference of the opening of the housing 101. The end cap 102 and the housing 101 are connected and fixed by the connecting portion to achieve a seal between the end cap 102 and the housing 101. The connecting portion is the portion where the weld mark is formed after the end cap 102 and the housing 101 are welded together, and can be the portion where the end cap 102 and the housing 101 are welded and fused together.

[0108] The end cap 102 is provided with an electrical connection portion 30 , which is electrically connected to the positive electrode sheet 21 or the negative electrode sheet 22 , thereby inputting or outputting electrical energy of the battery cell 100 .

[0109] The electrode assembly 20 is housed within the housing 101. The electrode assembly 20 may be a laminated structure or a wound structure. The housing 101 may contain one or more electrode assemblies 20. If there are multiple electrode assemblies 20, the multiple electrode assemblies 20 may be stacked, for example, stacked along the second direction F2.

[0110] The electrode assembly 20 can be a laminated type, that is, multiple pole pieces of the electrode assembly 20 are stacked, and the pole pieces are stacked to form a flat area 23. The electrode assembly 20 is in a stacked state as a whole. In the flat area 23, the positive pole piece 21, the negative pole piece 22 and at least a portion of the isolation member 25 are stacked along the second direction F2, so that the expansion deformation of the electrode assembly 20 is particularly obvious in the second direction F2.

[0111] The electrode assembly 20 can also be a wound type. The positive electrode sheet 21 and the negative electrode sheet 22 of the electrode assembly 20 are stacked and wound with the separator 25, and a straight area 23 and a corner area 24 are formed. The straight area 23 refers to the part of the electrode sheet extending along the plane after winding, and the part of the electrode assembly 20 in the straight area 23 is in a stacked state; the corner area 24 refers to the part of the electrode sheet extending along the arc surface after winding, and the outer surface of the corner area 24 is at least partially an arc surface. The straight area 23 connects the two corner areas 24. In the straight area 23, part of the positive electrode sheet 21, part of the negative electrode sheet 22 and part of the separator 25 are stacked along the second direction F2. 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 pierced by a straight line extending along the second direction F2, so that the expansion deformation of the electrode assembly 20 is particularly obvious in the second direction F2.

[0112] The housing 101 includes two first walls 11 . The two first walls 11 are respectively located on both sides of the electrode assembly 20 in the second direction F2 . Most of the expansion of the electrode assembly 20 acts on the first walls 11 .

[0113] The first wall 11 and the end cap 102 are welded to form a first connection portion 51. The first connection portion 51 may correspond one-to-one with the first wall 11. The first connection portion 51 is the portion with a weld mark formed after the end cap 102 and the first wall 11 are welded together. The first connection portion 51 may be the portion where the end cap 102 and the first wall 11 are welded and fused together. A portion of the first connection portion 51 is formed on the end cap 102, and another portion of the first connection portion 51 is formed on the first wall 11. The first wall 11 and the end cap 102 may be formed by saddle welding or penetration welding to form the first connection portion 51. The first connection portion 51 may be a portion of the connection portion or the entire connection portion.

[0114] The first wall 11 includes a first area 111 and a second area 112 arranged along the first direction F1. The first area 111 is located on a side of the second area 112 close to the first connecting portion 51. The first area 111 is a region where the thickness of the first wall 11 is thickened. The first area 111 is thicker than the second area 112.

[0115] The second area 112 has a first inner surface 1121 facing the inner space of the housing 101 and a first outer surface 1122 facing away from the inner space of the housing 101. The first area 111 may partially protrude from the first inner surface 1121 and / or the first outer surface 1122. Figure 8 In the illustrated embodiment, a portion of the first region 111 protrudes from the first inner surface 1121 , and an outer surface of the first region 111 is coplanar with the first outer surface 1122 .

[0116] When the battery cell 100 is in the process of charging and discharging, the electrode assembly 20 will expand along the second direction F2 during the cycle. The first wall 11 will be deformed after being subjected to the expansion force of the electrode assembly 20, which may easily cause fatigue cracking in the area of ​​the first wall 11 near the first connection part 51. In addition, when the battery cell 100 produces gas abnormally, the first connection part 51 and the surrounding areas are also prone to damage and cracking under relatively high pressure, and the long-term reliability is low. In the present application, the thickness of the first area 111 is set to be greater than the thickness of the second area 112 to achieve thickening at the opening of the shell 101. Here, the thickness of the first area 111 refers to the maximum thickness of the first area 111. The first area 111 has a certain strengthening effect on the first wall 11 located at the first connection part 51 and the surrounding areas, thereby improving the structural strength and reducing the risk of cracking and damage in the first connection part 51 and the surrounding areas, thereby improving the reliability and service life of the battery cell 100.

[0117] Among them, if the first area 111 is too thickened relative to the second area 112, it will make the first wall 11 difficult to manufacture and form. Therefore, the difference t between the thickness of the first area 111 and the thickness of the second area 112 is limited to be equal to 0.6 mm, or less than 0.6 mm. t can be any point value among 0.01 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, or a range value between any two of them.

[0118] In order to reduce the risk of cracking and damage in the first connecting portion 51 and the vicinity thereof, the electrode assembly 20 is further spaced apart from the inner surface of the first wall 11. Specifically, when the battery cell 100 is in a 0% state of charge, that is, when SOC=0, the battery is fully discharged, the total thickness of the straight areas 23 of N1 electrode assemblies 20 in the second direction F2 is X1, and the distance between the inner surfaces of the second areas 112 of the two first walls 11 is X2. The difference between X2 and X1 is limited to a range equal to or greater than 0.03 mm. By appropriately increasing the distance between the electrode assembly 20 and the inner surface of the first wall 11, the first connecting portion 51 and the vicinity thereof are unlikely to crack and damage when the thickness of the first area 111 is thickened to less than 0.6 mm.

[0119] In addition, if the gap between the electrode assembly 20 and the inner surface of the first wall 11 is larger, the size of the electrode assembly 20 is smaller, and the energy density of the battery cell 100 is lower. Therefore, the difference between X2 and X1 is limited to a range equal to or less than 0.5 mm. That is, the difference between X2 and X1 can be any point value of 0.03 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or a range value between any two of them. This can reduce the risk of cracking and damage of the first connecting portion 51 and the area near it, and can avoid to a certain extent the problem of excessive reduction in energy of the battery cell 100 due to the reduction in the size of the electrode assembly 20, thereby ensuring the energy density of the battery cell 100 to a certain extent.

[0120] In addition, charging the battery cell at a constant current rate of 0.33C to the upper limit of the battery charge voltage, and then charging it at a constant voltage rate of 0.05C corresponds to a battery cell state of 100% SOC; discharging the battery cell at a constant current rate of 0.33C to the cutoff voltage corresponds to a battery cell state of 0% SOC. For example, if the positive electrode material includes lithium-containing phosphate, the upper limit of the battery charge voltage can be 3.8V; and the battery discharge cutoff voltage can be 2.0V.

[0121] In the technical solution of the embodiment of the present application, by thickening the first area 111 of the first wall 11 and limiting the thickening thickness difference t to less than or equal to 0.6 mm, and at the same time limiting the difference between the distance X1 between the inner surfaces of the two second areas 112 and the total thickness X2 of the electrode assembly 20 to between 0.03 mm and 0.5 mm, the strength of the first area 111 can be improved, the probability of cracking and damage of the first connecting portion 51 and its vicinity can be reduced, the reliability of the battery cell 100 can be improved, the manufacturing and molding of the shell 101 can be facilitated, and the energy density of the battery cell 100 can be guaranteed to a certain extent.

[0122] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0123] Example 1

[0124] 1) Preparation of positive electrode sheet

[0125] The positive electrode active material LiNi0.7Co0.1Mn0.1O2, the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) are prepared into a positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the mass ratio of LiNi0.7Co0.1Mn0.1O2, Super P, and PVDF in the solid components is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, the positive electrode sheet is trimmed, cut into pieces, and divided into strips, and then dried under vacuum conditions at 85°C for 4 hours to make a positive electrode sheet.

[0126] 2) Preparation of negative electrode sheet

[0127] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry is 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC and adhesive styrene butadiene rubber (SBR) in the solid components is 88:7:3:2. The negative electrode slurry is coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C, and then cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to prepare a negative electrode sheet.

[0128] 3) Preparation of electrolyte

[0129] In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after mixing evenly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0130] 4) Isolation parts

[0131] A 16 μm polyethylene film was used as a separator.

[0132] 5) Lithium-ion battery preparation

[0133] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed in the middle of the positive and negative electrode sheets to isolate the positive and negative electrodes. The electrode assembly is wound and the tabs are welded. The electrode assembly is placed in an aluminum casing, and the prepared electrolyte is injected into the dried casing. The battery is packaged, allowed to stand, formed, shaped, and capacity tested to complete the preparation of the lithium-ion battery.

[0134] In which, the outer shell includes a shell and an end cover. The shell is a structure with an open end in the first direction. The end cover closes the opening and is welded to the shell. The shell includes two first walls and a second wall. The first wall and the end cover are welded to form a first connecting portion. The first wall has a first area and a second area. The distance between the inner surfaces of the second areas of the two first walls is X2. In the first direction, the first area is located on the side of the second area close to the first connecting portion, and the thickness of the first area is greater than the thickness of the second area. The difference between the thickness of the first area and the thickness of the second area is t.

[0135] There are two electrode assemblies in the housing. The outer surface area of ​​the flat area of ​​each electrode assembly is S, S = 20000mm 2 , the thickness dimension of the electrode assembly in the second direction is X1.

[0136] The method for measuring the fatigue times of battery cells is as follows:

[0137] 1) Prepare a special test fixture. Specifically, the fixture consists of three 10mm steel plates (first steel plate, second steel plate, and third steel plate). Each steel plate can completely cover the large surface of the battery cell. The first and third steel plates are located at both ends of the fixture and are fixed by bolts. The second steel plate is located between the first and third steel plates and is constrained by a guide rail. The second steel plate can only move in a direction perpendicular to the plane of the steel plates.

[0138] 2) A support structure is placed between the largest outer surface of one side of the battery cell and the first steel plate, and between the largest outer surface of the other side of the battery cell and the second steel plate (i.e., a support structure is placed on both sides of the battery cell in the expansion direction of the electrode assembly). The support structure can be an insulation pad or a water-cooling plate (consistent with the material / structure between the battery cells in the actual battery). The support structure can be compressed to provide expansion space for the battery cell during the charge and discharge cycle aging process; the largest outer surface of one side of the battery cell is laminated to the support structure, the first steel plate is laminated to the corresponding support structure, the second steel plate is laminated to the corresponding support structure, and a pressure sensor is provided between the second and third steel plates;

[0139] 3) Adjust the position of the second steel plate by adjusting the pre-tightening force of the bolts, observe the pressure sensor, make the initial extrusion force of the battery cell 2000N, and connect the two electrical connection parts of the battery cell to the dedicated battery charging and discharging equipment;

[0140] 4) Place the battery cell and fixture in a constant temperature environment of 25±2℃ and start the test after the battery cell reaches temperature equilibrium;

[0141] 5) The test steps are carried out in accordance with Section 6.4 "Standard Cycle Life" of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles, and the test cycle end condition is changed to "stop the test until damage occurs in the welding area of ​​the shell and end cover."

[0142] Specifically, test according to the following steps:

[0143] a) Discharge to 2V with a current of 1I1(A);

[0144] b) Leave it for no less than 30 minutes;

[0145] c) Charge in accordance with the method 6.1.1.3 of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles;

[0146] d) Leave it for no less than 30 minutes;

[0147] e) Discharge to 2V with a current of 1I1(A);

[0148] f) Repeat steps b) to e) until damage occurs in the weld area between the shell and the end cover. Stop the test.

[0149] That is, during the test process, the shell and end cover welding area of ​​the battery cell are continuously observed until the shell and end cover welding area are damaged and cracked, and the number of cycles is recorded as the cycle fatigue number of the battery cell.

[0150] The preparation method of the battery cells in Examples 2-4 and Comparative Example 1 is the same as that in Example 1, with the specific differences being the values ​​of X1 and / or X2 and the thickness difference t between the first region and the second region, as shown in Table 1. The fatigue times of the batteries obtained in Examples 1-4 and Comparative Example 1 were characterized, and the characterization results are shown in Table 1.

[0151] Table 1

[0152] serial number X1(mm) X2(mm) X2-X1(mm) t(mm) Technical Effects Comparative Example 1 84.99 85 0.01 0.6 Fatigue times: 1556 Example 1 84.97 85 0.03 0.6 Fatigue times: 2183 Example 2 49.95 50 0.05 0.45 Fatigue times: 2670 Example 3 29.7 30 0.3 0.2 Fatigue times 3320 Example 4 19.5 20 0.5 0.01 Fatigue times 3512

[0153] From the data of Examples 1-4 and Comparative Example 1, it can be seen that when X2-X1 is less than 0.03mm, the number of fatigue times is less than 2000, which is relatively low and difficult to meet the life requirements. Since excessive X2-X1 will affect the energy density of the battery cell 100, limiting X2-X1 to between 0.03mm-0.5mm can not only improve the strength of the first area 111, reduce the probability of cracking and damage in the first connecting portion 51 and its vicinity, improve the reliability of the battery cell 100, but also facilitate the manufacturing and molding of the shell 101, and can also ensure the energy density of the battery cell 100 to a certain extent.

[0154] In some embodiments, the total thickness of the straight areas 23 of the N1 electrode assemblies 20 in the second direction F2 is X1, and the distance between the inner surfaces of the second areas 112 of the two first walls 11 is X2, satisfying 0.05mm≤X2-X1≤0.3mm, and X2-X1 can be any point value of 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm or a range value between any two of them. Thus, the probability of cracking and damage of the first connecting portion 51 and its vicinity can be further reduced, the strength of the first connecting portion 51 and its vicinity can be improved, the reliability of the battery cell 100 can be improved, and the energy density of the battery cell 100 can also be improved.

[0155] In some embodiments, 20mm≤X2≤85mm, that is, when the battery cell 100 is in a 0% state of charge, the distance X2 between the inner surfaces of the second areas 112 of the two first walls 11 can be any point value of 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 85mm or a range value between any two of them, thereby increasing the internal space of the shell 101 to a certain extent, making it convenient to accommodate a certain number of electrode assemblies 20 of a certain size, and in the battery cell 100 that meets the above dimensions, by thickening the first area 111 of the first wall 11, and the thickening size is 0.6mm or less, it is convenient for the manufacturing and forming of the shell 101, and can also improve the strength of the first area 111, reduce the probability of cracking and damage of the first connecting portion 51 and its vicinity, and improve the reliability of the battery cell 100.

[0156] In some embodiments, 19.5mm≤X1≤84.97mm, that is, when the battery cell 100 is in a 0% state of charge, the total thickness X1 of the straight area 23 of the N1 electrode assemblies 20 in the second direction F2 can be any point value of 19.5mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 84.97mm or a range value between any two of them. This can ensure the energy density of the battery cell 100 to a certain extent, and in the battery cell 100 that meets the above dimensions, by thickening the first area 111 of the first wall 11, and the thickening size is 0.6mm or less, it is convenient for the manufacturing and forming of the shell 101, and can also improve the strength of the first area 111, reduce the probability of cracking and damage of the first connecting portion 51 and its vicinity, and improve the reliability of the battery cell 100.

[0157] In some embodiments, each electrode assembly 20 includes 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 straight area 23. At least a portion of the positive electrode sheet 21, at least a portion of the negative electrode sheet 22, and at least a portion of the separator 25 are stacked in the straight area 23 along the second direction F2. The number of layers of positive electrode sheets 21 stacked in the straight area 23 of each electrode assembly 20 is N2. The straight area 23 has an outer surface perpendicular to the first direction F1, and the area of ​​the outer surface is S, N1 ≥ 1, N2 ≥ 1, N1 * N2 ≤ 500, and S ≤ 80000 mm 2 .

[0158] Regardless of whether the electrode assembly 20 is a wound or laminated type, in the straight area 23 of the electrode assembly 20, the more layers of stacked positive electrode sheets 21, the more corresponding negative electrode sheets 22 are required, and the greater the expansion and deformation of the electrode assembly 20. Therefore, the expansion of the electrode assembly 20 is positively correlated with the number of layers of positive electrode sheets 21. The larger the area of ​​the outer surface of the straight area 23 perpendicular to the second direction F2, the greater the expansion and deformation of the electrode assembly 20, and the higher the risk of cracking and damage of the first connecting portion 51 and its vicinity. Therefore, the total number of layers N1*N2 of positive electrode sheets 21 stacked in the straight area 23 is limited to a range equal to or less than 500, and the area S of the outer surface of the straight area 23 perpendicular to the second direction F2 is limited to 80,000 mm 2 Or less than 80000mm 2 Within the range, the expansion of the electrode assembly 20 can be reduced during the charge and discharge process of the battery cell 100, thereby reducing the probability of cracking and damage of the first connecting portion 51 and its vicinity, thereby improving the reliability of the battery cell 100.

[0159] The method for measuring N2 is as follows: after disassembling the battery cell 100 and removing the electrode assembly 20, the number of layers of the positive electrode sheet 21 in the second direction F2 in the flat area 23 is calculated without destroying the integrity of the electrode assembly 20. Figure 5-Figure 7 As shown, the measurement method of S here is the product of the height dimension M2 of the outer plane of the flat area 23 perpendicular to the first direction F1 in the first direction F1 and the length dimension M1 in the third direction F3.

[0160] like Figure 8 and Figure 9 As shown, in some embodiments, the first region 111 includes a first portion 111a and a second portion 111b arranged along a first direction F1, the second portion 111b connects the first portion 111a and the second region 112, the thickness of the first portion 111a is the thickness of the first region 111, and the thickness of the second portion 111b tends to decrease in the direction from the end cover 102 to the electrode assembly 20.

[0161] like Figure 8 and Figure 9 As shown, the first part 111a is a structure of constant thickness, the second part 111b is a structure of variable thickness, and the maximum thickness of the second part 111b is the same as the thickness of the first part 111a, that is, equivalent to the thickness of the first area 111, and the minimum thickness of the second part 111b is the same as the thickness of the second area 112. Therefore, the first area 111 has a structure of partially constant thickness and partially variable thickness, which not only facilitates the manufacturing and forming of the first wall 11, but also can play a certain strengthening role on the first wall 11, thereby improving the structural strength of the first area 111, reducing the risk of cracking and damage of the first connecting portion 51 and the area near it, and thus improving the reliability and service life of the battery cell 100.

[0162] like Figure 8 and Figure 9 As shown, in some embodiments, along the first direction F1, the height dimension of the first part 111a is H1. If the height dimension of the first part 111a is too small, the first part 111a will be smaller than the depth of the first connecting portion 51, thereby affecting the strength of the connection between the shell 101 and the end cover 102, causing cracks in the weld, etc.

[0163] In addition, when the first part 111a extends to one side of the main body of the electrode assembly 20 in the second direction F2, that is, the first part 111a and the main body of the electrode assembly 20 have an intersection in the first direction F1, the first part 111a and the main body of the electrode assembly 20 will interfere with each other, and thus the first part 111a and the main body of the electrode assembly 20 need to be staggered in the first direction F1. At this time, if the height dimension of the first part 111a is too large, that is, in the first direction F1, the first part 111a occupies too much space, resulting in a reduction in the space available to accommodate the electrode assembly 20, thereby affecting the energy density of the battery cell 100. For this reason, the height dimension H1 of the first part 111a is limited to between 0.7mm and 10mm, and H1 can be any point value of 0.71mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, or a range value between any two of them.

[0164] In this way, the structural strength of the first connecting portion 51 can be ensured to a certain extent, and the space occupied by the electrode assembly 20 can be reduced, thereby avoiding a reduction in the energy density of the battery cell 100 to a certain extent.

[0165] In some embodiments, along the first direction F1, the height dimension of the first area 111 is H2, and the height dimension of the first part 111a is H1, wherein H2>H1, and 1.5mm

[0166] like Figure 8 and Figure 9 As shown, in some embodiments, the second zone 112 has a first inner surface 1121 facing the interior space of the shell 101 and a first outer surface 1122 facing away from the interior of the shell 101, the first zone 111 includes a first protrusion 1111 protruding from the first inner surface 1121, and / or the first zone 111 includes a second protrusion 1112 protruding from the first outer surface 1122.

[0167] like Figure 8 As shown, the first area 111 includes a first protrusion 1111, the first protrusion 1111 protrudes from the first inner surface 1121, and the outer surface of the first area 111 is coplanar with the first outer surface 1122. As a result, the outer surface of the shell 101 is flat, which facilitates the plurality of battery cells 100 to be arranged in a direction perpendicular to the first wall 11 (such as Figure 8 The second direction F2) is shown as stacked arrangement.

[0168] Of course, the first zone 111 can also only include the second protrusion 1112, and the second protrusion 1112 protrudes from the first outer surface 1122, so that the thickened area of ​​the first wall 11 does not occupy the internal space of the shell 101, which facilitates the assembly of the electrode assembly 20 into the shell 101, reduces the probability of interference between the electrode assembly 20 and the first zone 111 during assembly, increases the capacity of the electrode assembly 20 to a certain extent, and thereby improves the energy density of the battery cell 100.

[0169] like Figure 9 ​As shown, the first area 111 includes a first protrusion 1111 and a second protrusion 1112. The first protrusion 1111 protrudes from the first inner surface 1121, and the second protrusion 1112 protrudes from the first outer surface 1122. Therefore, the thickness dimension of the first protrusion 1111 protruding from the first inner surface 1121 is t1, and the thickness dimension of the second protrusion 1112 protruding from the first outer surface 1122 is t2. The sum of t1 and t2 is the difference t between the thickness of the first area 111 and the thickness of the second area 112. Therefore, by sharing the thickened thickness on the inner and outer sides, the thickness of the protrusion on each side is reduced on the basis of increasing the thickness of the first area 111, which further facilitates the manufacturing and forming of the shell 101, and at the same time helps to reduce the thickness dimension of the inner protrusion, so that the electrode assembly 20 is convenient to be assembled into the shell 101.

[0170] In some embodiments, the positive electrode plate 21 includes a positive electrode main area and a positive electrode tab protruding from the positive electrode main area, and the negative electrode plate 22 includes a negative electrode main area and a negative electrode tab protruding from the negative electrode main area. In the projection plane perpendicular to the second direction F2, the orthographic projection of the positive electrode plate 21 does not overlap with the orthographic projection of the first area 111; and / or, in the projection plane perpendicular to the second direction F2, the orthographic projection of the negative electrode main area does not overlap with the orthographic projection of the first area 111.

[0171] If, in a projection plane perpendicular to the second direction F2, the orthographic projection of the positive electrode main area does not overlap with the orthographic projection of the first protrusion 1111, the shell 101 can provide a larger expansion space for the electrode assembly 20, thereby reducing the risk of the electrode assembly 20 directly applying an expansion force to the first protrusion 1111 due to expansion, reducing the deformation of the first wall 11, and further reducing the risk of fatigue cracking in the area of ​​the first wall 11 near the first connecting portion 51.

[0172] If, in a projection plane perpendicular to the second direction F2, the orthographic projection of the negative electrode main area does not overlap with the orthographic projection of the first protrusion 1111, the shell 101 can provide a larger expansion space for the electrode assembly 20, thereby reducing the risk of the electrode assembly 20 directly applying an expansion force to the first protrusion 1111 due to expansion, reducing the deformation of the first wall 11, and further reducing the risk of fatigue cracking in the area of ​​the first wall 11 near the first connecting portion 51.

[0173] In some embodiments, please refer to Figure 10 , Figure 10Schematic diagram of the connection between the end cap 102 and the electrical connection portion 30 provided in some embodiments of the present application. The battery cell 100 also includes an electrical connection portion 30, which is provided on the end cap 102 and electrically connected to the electrode assembly 20. The end cap 102 is provided with an extraction hole. The electrical connection portion 30 includes a terminal body 31, a first stopper 32, and a second stopper 33. The terminal body 31 connects the first stopper 32 and the second stopper 33. The terminal body 31 is provided through the extraction hole. Along the first direction F1, the first stopper 32 is located on the side of the end cap 102 facing away from the electrode assembly 20, and the second stopper 33 is located on the side of the end cap 102 facing the electrode assembly 20.

[0174] 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 two 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 first direction F1, 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.

[0175] As an example, the battery cell 100 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.

[0176] 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.

[0177] like Figure 6 As shown, in some embodiments, the electrode assembly 20 is a laminate 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 the second direction F2.

[0178] As an example, the positive electrode sheets 21 and the negative electrode sheets 22 in the electrode assembly 20 are alternately arranged along the second direction F2 , and a separator 25 is provided between the positive electrode sheets 21 and the negative electrode sheets 22 .

[0179] In this embodiment, the electrode assembly 20 is a laminated electrode assembly 20 , which has a more compact structure and a stronger anti-extrusion capability.

[0180] 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 .

[0181] As an example, there is one more negative electrode sheet 22 than positive electrode sheet 21 .

[0182] 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.

[0183] In some embodiments, along the third direction F3 , the size of the first region 111 is larger than the size of the positive electrode sheet 21 and / or the size of the negative electrode sheet 22 , and the first direction F1 , the second direction F2 and the third direction F3 are perpendicular to each other.

[0184] If along the third direction F3, the size of the first region 111 is larger than the size of the positive electrode sheet 21, the first region 111 extends beyond at least one end of the positive electrode sheet 21 along the third direction F3; if along the third direction F3, the size of the first region 111 is larger than the size of the negative electrode sheet 22, the first region 111 extends beyond at least one end of the negative electrode sheet 22 along the third direction F3.

[0185] In this embodiment, along the third direction F3, the size of the first region 111 is larger than the size of the positive electrode sheet 21 and / or the size of the negative electrode sheet 22, so that the size of the first region 111 along the third direction F3 is larger, so that the strength of more areas of the first wall 11 along the third direction F3 is enhanced, further reducing the risk of fatigue cracking in the area of ​​the first wall 11 near the first connecting portion 51.

[0186] like Figure 5 As shown, in some embodiments, the electrode assembly 20 is a winding structure, and the electrode assembly 20 also has a corner area 24, and the straight area 23 is provided with a corner area 24 at at least one end along the third direction, and at least a portion of the outer surface of the corner area 24 is a circular arc surface, and the first direction F1, the second direction F2 and the third direction are not coplanar and intersect with each other.

[0187] The straight region 23 may have a corner region 24 at only one end along the third direction F3, or at both opposite ends along the third direction F3. The first direction F1, the second direction F2, and the third direction F3 are not coplanar. Any two of the first direction F1, the second direction F2, and the third direction F3 may form an acute, right, or obtuse angle. The outer surface of the corner region 24 may be an entire arc surface, or only a portion thereof.

[0188] As an example, the positive electrode sheet 21, the separator 25 and the negative electrode sheet 22 are stacked and wound to form a winding structure. The first direction F1, the second direction F2 and the third direction F3 are perpendicular to each other, and corner areas 24 are provided at both ends of the straight area 23 along the third direction F3. The portions of the positive electrode sheet 21, the negative electrode sheet 22 and the separator 25 located in the corner area 24 are in a bent state, and the portion of the positive electrode sheet 21 located in the corner area 24 can be at least partially arc-shaped, the portion of the negative electrode sheet 22 located in the corner area 24 can be at least partially arc-shaped, and the portion of the separator 25 located in the corner area 24 can be at least partially arc-shaped. Along the winding direction of the electrode assembly 20, the outermost circle of the electrode assembly 20 is the separator 25, wherein the outer surface of the straight area 23 and the outer surface of the corner area 24 are part of the outer surface of the outermost circle of the electrode assembly 20.

[0189] The outer surface of the straight region 23 is a plane, while the outer surface of the corner region 24 is an arcuate surface, with the axis of the arcuate surface extending along the first direction F1. Along the second direction F2, the surfaces on both sides of the straight region 23 are both planes. Along the third direction F3, the surface of one corner region 24 facing away from the other corner region 24 is an arcuate surface, and the surface of the other corner region 24 facing away from the first corner region 24 is another arcuate surface.

[0190] For the wound electrode assembly 20, the straight region 23 expands more significantly in the second direction F2. Because the first region 111 reinforces the area of ​​the first wall 11 near the first connection portion 51, the risk of fatigue cracking of the first wall 11 near the first connection portion 51 due to expansion of the electrode assembly 20 can be effectively reduced.

[0191] The battery 1000 according to the second embodiment of the present application includes the battery cell 100 according to the first embodiment of the present application, and the power-consuming device 2000 according to the third embodiment of the present application includes the battery 1000 according to the second embodiment of the present application. The battery 1000 is used to provide power to the power-consuming device 2000. Therefore, the use of the battery 1000 can help improve the safety and reliability of the power-consuming device 2000.

[0192] 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.

[0193] 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.

[0194] As shown in Figure 1 , the battery 1000 is arranged at the bottom of the vehicle, and as shown in Figure 2 , the battery 1000 includes a plurality of battery monomers 100, as shown in Figure 4 , each battery monomer 100 includes an outer shell 10 and two electrode assemblies 20, the outer shell 10 is provided with an electrical connection part 30 and a pressure relief part 40, the electrical connection part 30 and the pressure relief part 40 are located at different sides of the outer shell 10; the electrode assembly 20 is arranged in the outer shell 10.

[0195] Each electrode assembly 20 includes a flat area 23, the total thickness of the flat area 23 of N1 electrode assemblies 20 in the second direction F2 is X1 when the battery monomer 100 is at 0% state of charge, the distance between the inner surfaces of the second areas 112 of the two first walls 11 is X2, wherein 0.03mm≤X2-X1≤0.5mm, 20mm≤X2≤85mm, 19.5mm≤X1≤84.97mm.

[0196] The first wall 11 is welded with the end cover 102 to form a first connecting part 51, the first wall 11 includes a first area 111 and a second area 112 arranged along the first direction F1, the first area 111 is located on the side of the second area 112 close to the first connecting part 51, the thickness of the first area 111 is greater than the thickness of the second area 112; the difference between the thickness of the first area 111 and the thickness of the second area 112 is t, t≤0.6mm.

[0197] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature 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: include: A housing having an opening at at least one end along a first direction, the housing comprising two first walls, the two first walls being arranged opposite to each other along a second direction, the first direction intersecting the second direction; an end cap, closing the opening, the first wall and the end cap being welded to form a first connecting portion; the first wall comprising a first region and a second region arranged along the first direction, the first region being located on a side of the second region close to the first connecting portion, the thickness of the first region being greater than the thickness of the second region; a difference between the thickness of the first region and the thickness of the second region being t, satisfying the following: t≤0.6 mm; N1 electrode assemblies are accommodated in the shell, each of the electrode assemblies includes a flat area, and when the battery cell is in a 0% state of charge, the total thickness of the flat areas of the N1 electrode assemblies in the second direction is X1, and the distance between the inner surfaces of the second areas of the two first walls is X2, satisfying: 0.03mm≤X2-X1≤0.5mm.

2. The battery cell according to claim 1, wherein: Satisfies: 0.05mm≤X2-X1≤0.3mm.

3. The battery cell according to claim 1, wherein: Meets: 20mm≤X2≤85mm.

4. The battery cell according to claim 1, wherein: Meets: 19.5mm≤X1≤84.97mm.

5. The battery cell according to claim 1, characterized in that Each of the electrode assemblies includes at least one positive electrode sheet, at least one negative electrode sheet, and at least one separator. The positive electrode sheet, the negative electrode sheet, and the separator are stacked to form a flat area. At least a portion of the positive electrode sheet, at least a portion of the negative electrode sheet, and at least a portion of the separator are stacked along the second direction in the flat area. The number of layers of the positive electrode sheets stacked in the flat area of ​​each electrode assembly is N2. The flat area has an outer surface perpendicular to the first direction, and the area of ​​the outer surface is S, N1≥1, N2≥1, N1*N2≤500, and S≤80000mm 2 .

6. The battery cell according to claim 1, characterized in that The first zone includes a first part and a second part arranged along the first direction, the second part connects the first part and the second zone, the thickness of the first part is the thickness of the first zone, and the thickness of the second part tends to decrease along the direction from the end cover to the electrode assembly.

7. The battery cell according to claim 6, characterized in that Along the first direction, the height dimension of the first portion is H1, which satisfies: 0.7 mm<H1≤10 mm.

8. The battery cell according to claim 6, characterized in that Along the first direction, the height dimension of the first area is H2, and the height dimension of the first part is H1, satisfying: H2>H1, 1.5mm<H2≤H1+5mm.

9. The battery cell according to claim 5, characterized in that: The positive electrode plate includes a positive electrode main area and a positive electrode tab protruding from the positive electrode main area, and the negative electrode plate includes a negative electrode main area and a negative electrode tab protruding from the negative electrode main area. In a projection plane perpendicular to the second direction, the orthographic projection of the positive electrode plate does not overlap with the orthographic projection of the first area; and / or, in a projection plane perpendicular to the second direction, the orthographic projection of the negative electrode main area does not overlap with the orthographic projection of the first area.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The second area has a first inner surface facing the inner space of the shell and a first outer surface facing away from the interior of the shell, the first area includes a first protrusion protruding from the first inner surface, and / or the first area includes a second protrusion protruding from the first outer surface.

11. The battery cell according to claim 1, wherein The battery cell further includes an electrical connection portion, the electrical connection portion being provided on the end cover and electrically connected to the electrode assembly; 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.

12. The battery cell according to claim 1, wherein 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 second direction.

13. The battery cell according to claim 12, characterized in that: Along the third direction, the size of the first region is larger than the size of the positive electrode sheet and / or the size of the negative electrode sheet, and the first direction, the second direction and the third direction are perpendicular to each other.

14. The battery cell according to claim 1, characterized in that The electrode assembly is a wound structure and further has a corner area. The corner area is provided at at least one end of the straight area along the third direction. At least a portion of the outer surface of the corner area is a circular arc surface. The first direction, the second direction and the third direction are not coplanar and intersect with each other.

15. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 14.

16. An electrical device, characterized in that: The battery according to claim 15 is used to provide electrical energy to the electrical device.

Images