Patent Publication Number: US-2023155184-A1

Title: Battery cell, battery, electrical apparatus, and manufacturing method for battery cell

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of PCT Patent Application No. PCT/CN2021/120669, entitled “BATTERY CELL, BATTERY, ELECTRICAL APPARATUS, AND MANUFACTURING METHOD FOR BATTERY CELL” filed on Sep. 26, 2021, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present application relates to the technical field of batteries, and in particular, to a battery cell, a battery, an electrical apparatus, and a manufacturing method for a battery cell. 
     BACKGROUND ART 
     Energy saving and emission reduction are key to the sustainable development of automobile industry, and electric vehicles have become an important part of the sustainable development of automotive industry due to their advantages of energy saving and environmental protection. For electric vehicles, battery technology is an important factor related to their development. 
     An electrode assembly is an important unit of a battery cell. In order to improve energy density of a battery, tabs of the electrode assembly need to be bent to save space. However, when tabs of a plurality of layers of tab sheets are bent, safety performance of the battery may be affected. 
     SUMMARY OF THE INVENTION 
     In view of the above problems, a battery cell, a battery, an electrical apparatus, and a manufacturing method for a battery cell are provided in the present application, so as to alleviate the battery safety problem caused when a tab is bent. 
     In a first aspect, a battery cell including an electrode assembly is provided in the present application, and the electrode assembly includes a main body part and a tab extending from the main body part, wherein the tab is formed by bending a plurality of tab sheets stacked in layers; the tab includes a first bending portion and a straight portion, and the straight portion is connected to the main body part through the first bending portion; a second bending portion is formed at least on the straight portion, and the second bending portion protrudes towards the side of the main body part. 
     In the technical solution of the embodiments of the present application, the arrangement of the second bending portion makes a part of the tab generate a protruding deformation towards the side of the main body part, and this deformation makes the layers of the tab close together, forming a local binding of the tab, and increasing the resistance to separation between the layers of the tab, thereby avoiding bifurcation of the tab and improving the safety of the battery. 
     In some embodiments, second bending portions are formed on the straight portion and the first bending portion. The second bending portion is formed on the straight portion and the first bending portion, so that an area where the tab is bound is larger, and the bifurcation of the tab is further avoided. 
     In some embodiments, the first bending portion has a first bending axis, the second bending portion has a second bending axis, and the second bending axis and the first bending axis have an included angle or are parallel. The second bending portion makes the layers of the tab converge to the middle of the second bending portion, and the separation resistance is greater, thereby avoiding the bifurcation of the tab. 
     In some embodiments, the battery cell further includes a case, an end cover, and a pressing-down structure. The case has an opening, the end cover is arranged at the opening to close the opening, and the tab extends from the main body part to the side of the end cover. The pressing-down structure is arranged between the tab and the end cover, and the pressing-down structure abuts against the tab, so that the tab forms the second bending portion. The pressing-down structure is arranged between the tab and the end cover, so that after the battery cell is assembled, the pressing-down structure can continue to abut against the tab, and therefore, the shape of the second bending portion on the tab is maintained continuously, thereby effectively ensuring the continuous converging effect between the various layers of tab sheets of the tab, and preventing the tab bifurcation. 
     In some embodiments, the battery cell further includes a terminal post arranged on the end cover and an adapter plate. The adapter plate is configured to connect the terminal post and the straight portion of the tab, and the pressing-down structure is arranged at a position of the adapter plate that cooperates with the straight portion. By arranging the pressing-down structure on the adapter plate and at the position of the adapter plate that cooperates with the straight portion, after the adapter plate is connected to the straight portion of the tab, the pressing-down structure can naturally form downward pressing on the tab. Therefore, this arrangement facilitates assembling of the battery cell. 
     In some embodiments, the battery cell further includes a terminal post arranged on the end cover and an adapter plate. The adapter plate is configured to connect the terminal post and the straight portion of the tab, and the pressing-down structure is arranged at positions where the adapter plate cooperates with the straight portion and the first bending portion. By arranging the pressing-down structure at the positions where the adapter plate cooperates with the straight portion and the first bending portion, the second bending portion is formed on the straight portion and the first bending portion of the tab, so that an area where the tab is bound is larger, and the bifurcation of the tab is further avoided. 
     In some embodiments, the pressing-down structure includes a protruding portion arranged on the adapter plate. The protruding portion abuts against an upper surface of the tab so that the tab forms the second bending portion facing one side of the main body part. 
     In some embodiments, the height of the protruding portion is 1 mm to 5 mm. Setting the height of the protruding portion within the above range can ensure that a protrusion depth of the second bending portion formed by the tab forms effectively binding for the layers of tab sheets. 
     In some embodiments, the height of the protruding portion gradually increases in a direction from the first bending portion to the straight portion. A free end of the straight portion is easier to disperse, and therefore, in order to make deformation of the free end side of the straight portion larger to form a larger binding force, the height of the protruding portion is set to gradually increase in the direction from the first bending portion to the straight portion. 
     In some embodiments, the protruding portion and the adapter plate are formed integrally. By integrally forming the protruding portion and the adapter plate, when the battery cell is assembled, directly connecting the adapter plate and the tab can at the same time realize the abutment of the protruding portion against the tab, so as to form the second bending portion. Therefore, the assembling process of the battery cell can be simplified. 
     In some embodiments, the protruding portion and the adapter plate are separated structures, and the protruding portion is connected to the adapter plate. The protruding portion and the adapter plate are separated structures, and in this way, a position of the protruding portion on the adapter plate can be changed according to an actual requirement during the assembling. 
     In some embodiments, the protruding portion has a contact surface abutting against the tab, and the contact surface includes a curved surface. The contact surface directly abuts against the tab, and therefore, setting the contact surface as the curved surface can avoid damage to the tab when abutting against the tab. 
     In some embodiments, the adapter plate includes a first connection region connected to the terminal post and a second connection region connected to the tab. The pressing-down structure and the first connection region are located at both sides of the second connection region. The pressing-down structure and the first connection region are located on both sides of the second connection region, respectively, and in this way, the arrangement of the pressing-down structure has no effect on the connections between the adapter plate and the terminal post and between the adapter plate and the tab. During assembling, the original process is still used for connecting the adapter plate to the terminal post and to the tab, and the pressing-down structure arranged on the adapter plate can naturally form pressing against the tab. 
     In some embodiments, the adapter plate includes a first connection region connected to the terminal post, and a second connection region and a third connection region connected to the tab. The pressing-down structure is located between the second connection region and the third connection region. The pressing-down structure is arranged between the second connection region and the third connection region, and therefore, both sides of the pressing-down structure are subject to a connection force between the adapter plate and the tab. Under the limit of the connection forces on the both sides, the pressing-down structure has a small degree of freedom in a height direction, and therefore, the abutment against the tab can be maintained continuously. 
     In some embodiments, the battery cell further includes a terminal post arranged on the end cover and an adapter plate. The adapter plate is configured to connect the terminal post and the tab, and the pressing-down structure is arranged on the side of the end cover facing the tab and at a position that is not blocked by the adapter plate. The end cover is provided with the pressing-down structure, so that when the end cover is installed at the opening of the case, the pressing-down structure can press against the tab so that the tab forms the second bending portion. 
     In some embodiments, in a direction of the first bending axis, the pressing-down structure abuts against a portion of the tab close to the middle of the tab. The pressing-down structure abuts against the portion of the tab close to the middle of the tab, and therefore, in a first direction, the second bending portion formed by the pressing-down structure is located in the middle of the tab, so that portions of the tab located at both sides of the second bending portion are subject to more balanced binding forces, and each part of the tab can receive a balanced binding force. 
     In some embodiments, the battery cell includes two or more electrode assemblies arranged side by side, and the pressing-down structure abuts against at least two tabs of the two or more electrode assemblies. The pressing-down structure abuts against at least two tabs of the two or more electrode assemblies, so that there is no need to provide a special pressing-down structure for each tab, thereby simplifying the assembling process of the battery cell and simplifying the structure of the battery cell. 
     In some embodiments, the electrode assembly includes a positive tab and a negative tab, and a second bending portion is formed on straight portions of the positive tab and the negative tab, respectively. The second bending portion is formed on the straight portions of the positive tab and the negative tab, respectively, and in this way, the positive tab and the negative tab can be effectively bifurcated, thereby further improving the safety of the battery cell. 
     In a second aspect, a battery is provided in the present application, and includes the battery cell in the above embodiment. 
     In a third aspect, an electrical apparatus is provided in the present application, and includes the battery in the above embodiment, and the battery is configured to provide electrical energy. 
     In a fourth aspect, a manufacturing method for a battery cell is provided in the present application, and includes the following steps: 
     providing an electrode assembly, the electrode assembly including a main body part and a tab, wherein the tab includes a first bending portion and a straight portion, the straight portion is connected to the main body part through the first bending portion, a second bending portion is formed at least on the straight portion, and the second bending portion protrudes towards the side of the main body part. 
     In some embodiments, the manufacturing method further includes providing a case having an opening, an end cover, and a pressing-down structure, the pressing-down structure being arranged between the tab and the end cover, placing the electrode assembly within the case and allowing the tab of the electrode assembly to be located on one side of the opening of the case. When the end cover is installed at the opening of the case to close the opening, the pressing-down structure is abutted against the tab to form the second bending portion of the tab. 
     In some embodiments, the manufacturing method further includes providing a terminal post and an adapter plate, connecting a first end of the adapter plate to the terminal post, arranging the pressing-down structure at a second end of the adapter plate, and abutting the pressing-down structure against the tab. 
     In some embodiments, the manufacturing method further includes arranging the pressing-down structure on the end cover, and installing the end cover at the opening of the case so that the pressing-down structure abuts against the tab. 
     The above description is only a summary of the technical solutions of the present application. In order to be able to understand the technical means of the present application more clearly, the technical means can be implemented according to the content of the specification. Furthermore, to make the above and other objectives, features and advantages of the present application more comprehensible, specific implementations of the present application are exemplified below. 
    
    
     
       DESCRIPTION OF DRAWINGS 
       In order to illustrate the technical solutions of the embodiments of the present application more clearly, the drawings required in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained according to the drawings without any creative effort. 
         FIG.  1    is a schematic structural diagram of a vehicle according to some embodiments of the present application; 
         FIG.  2    is a schematic exploded structural diagram of a battery according to some embodiments of the present application; 
         FIG.  3    is a schematic three-dimensional structural diagram of a battery cell according to some embodiments of the present application; 
         FIG.  4    is a schematic top-view structural diagram of a battery cell according to some embodiments of the present application; 
         FIG.  5    is a schematic sectional structural diagram of a battery cell in a direction A-A according to some embodiments of the present application: 
         FIG.  6    is a schematic partial enlarged structural diagram of a part N in  FIG.  5   ; 
         FIG.  7    is a schematic front-view structural diagram of a battery cell according to some embodiments of the present application; 
         FIG.  8    is a schematic sectional structural diagram of a battery cell in a direction C-C according to some embodiments of the present application; 
         FIG.  9    is a schematic partial enlarged structural diagram of a part N in  FIG.  8   ; 
         FIG.  10    is a schematic three-dimensional structural diagram of a tab according to some embodiments of the present application; 
         FIG.  11    is a schematic sectional structural diagram of a battery cell in a direction A-A according to some other embodiments of the present application; 
         FIG.  12    is a schematic partial enlarged structural diagram of a part Q in  FIG.  11   : 
         FIG.  13    is a schematic sectional structural diagram of a battery cell in a direction C-C according to some other embodiments of the present application: 
         FIG.  14    is a schematic partial enlarged structural diagram of a part P in  FIG.  13   ; and 
         FIG.  15    is a diagram of steps of a manufacturing method for a battery cell according to some embodiments of the present application. 
     
    
    
     In the drawings, the drawings are not drawn to actual scale. 
     Reference numerals in Detailed Description are as follows: 
     Vehicle  1000 ; 
     Battery  100 , Controller  200 , Motor  300 ; 
     Box body  10 , First portion  11 , Second portion  12 ; 
     Battery cell  20 , Case  21 , End cover  22 , Protruding portion  221 , Electrode assembly  23 , Main body part  231 . Tab  232 . First bending portion  232   a , Straight portion  232   b , Second bending portion  232   c , Terminal post  24 , Adapter plate  26 , Protruding portion  261 . 
     DETAILED DESCRIPTION 
     Embodiments of the technical solutions of the present application will be described in detail below in conjunction with the drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and therefore are only used as examples and cannot be used to limit the scope of protection of the present application. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art belonging to the technical field of the present application; the terms used herein are intended only for the purpose of describing specific embodiments and are not intended to limit the present application: the terms “including” and “having” and any variations thereof in the specification and the claims of the present application and in the description of drawings above are intended to cover non-exclusive inclusion. 
     In the description of the embodiments of the present application, the technical terms “first”, “second”, and the like are used only to distinguish between different objects, and are not to be understood as indicating or implying a relative importance or implicitly specifying the number, particular order, or primary and secondary relation of the technical features indicated. In the description of the embodiments of the present application, the meaning of “a plurality of” is two or more, unless otherwise explicitly and specifically defined. 
     Reference herein to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments. 
     In the description of the embodiments of the present application, the term “and/or” is only an association relationship for describing associated objects, indicating that three relationships may exist. For example, A and/or B may represent three situations: A exists alone, both A and B exist, and B exists alone. In addition, the character “/” herein generally means that the associated objects before and after it are in an “or” relationship. 
     In the description of the embodiments of the present application, the term “plurality of” refers to two or more (including two), and similarly, “multiple groups” refers to two or more (including two) groups, and “multiple sheets” refers to two or more (including two) sheets. 
     In the description of the embodiments of the present application, the orientation or location relationships indicated by the technical terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”. “top”, “bottom”, “inside”, “outside”. “clockwise”, “counterclockwise”, “axial”. “radial”, “circumferential” and the like are based on the orientation or location relationships shown in the drawings, and are only for convenience and simplification of the description of the embodiments of the present application, but do not indicate or imply that the apparatuses or elements referred to must have particular orientations, be constructed and operated in particular orientations, and therefore cannot be construed as a limitation of the embodiments of the present application. 
     In the description of the embodiments of the present application, unless otherwise expressly specified and limited, the technical terms “mounting,” “connected.” “connecting,” “fixing”, and the like shall be understood in a broad sense, which, for example, may be a fixed connection, or a detachable connection or an integral connection; may also be a mechanical connection, or an electrical connection; may be a direct connection, or an indirect connection through an intermediate medium, and may be a communication within two elements or an interactive relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations. 
     A current battery cell generally includes a case and an electrode assembly accommodated in the case, and the case is filled with an electrolyte solution. The electrode assembly is a component in which an electrochemical reaction takes place in the battery cell. One or more electrode assemblies may be contained within the case. The electrode assembly is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually arranged between the positive electrode sheet and the negative electrode sheet. Portions of the positive electrode sheet and the negative electrode sheet with active materials constitute a main body part of the electrode assembly, and portions of the positive electrode sheet and the negative electrode sheet without active materials constitute tabs, respectively. In order to improve the overcurrent capability, the tab includes multi-layer tab sheets arranged in layers. In charging and discharging processes of the battery cell, the positive active material and the negative active material react with the electrolyte solution, and the tabs are connected to terminal posts to form a current loop. 
     During processing of the battery cell, in order to save space and improve the energy density, it is generally necessary to bend the tab with the multi-layer tab sheets. After being bent, the tab includes a first bending portion connected to the main body part and a straight portion. The inventors of the present application noticed during the research that the tab includes multiple layers of tabs, and therefore, after bending, the layers of the tab are prone to bifurcation. In addition, the bifurcation between the layers of the tab may also cause the tab to be inserted into the main body part upside down to result in short-circuit with the electrode sheet below the tab, thereby causing a safety problem. 
     In order to alleviate the problem that the tab is prone to bifurcation, the inventors have found that a part of the tab may be made to protrude and deform, and the local deformation can form binding on the tab, thereby increasing a resistance to separation between the layers of the tab, and avoiding the tab bifurcation. After further in-depth research, the inventors found that a part of the tab can be protruded and deformed towards the side of the main body part, so as to avoid increasing the volume occupied by the electrode assembly on the basis of avoiding the tab bifurcation. 
     Based on the above considerations, in order to alleviate the problem that the tab is prone to bifurcation, the inventors designed a battery cell after in-depth research, in which at least a second bending portion is formed on a straight portion, and the second bending portion protrudes towards the side of the main body part. The arrangement of the second bending portion makes a part of the tab generate a protruding deformation towards the side of the main body part, and this deformation makes the layers of the tab close together, forming a local binding of the tab, and increasing the resistance to separation between the layers of the tab, thereby avoiding the tab bifurcation. 
     The battery cell disclosed in the embodiments of the present application can be used, but not limited to, in electrical apparatus such as a vehicle, a ship, or an aircraft. A power supply system including the battery cells and batteries disclosed in the present application may be used for forming an electrical apparatus. 
     Embodiments of the present application provide an electrical apparatus that uses a battery as a power supply, and the electrical apparatus may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery vehicle, an electric vehicle, a ship, a spacecraft, and so on. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy. The spacecraft may include an airplane, a rocket, a space shuttle, a spaceship, and the like. 
     In the following embodiments, for the convenience of description, an electrical apparatus according to an embodiment of the present application being vehicle  1000  is used as an example for description. 
     Referring to  FIG.  1   ,  FIG.  1    is a schematic structural diagram of vehicle  1000  according to some embodiments of the present application. Vehicle  1000  may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be an all-electric vehicle, a hybrid electric vehicle, an extended range electric vehicle, or the like. The interior of vehicle  1000  is provided with battery  100 , and battery  100  may be provided at the bottom or head or tail of vehicle  1000 . Battery  100  may be used to power vehicle  1000 , for example, battery  100  may serve as an operating power source for vehicle  1000 . Vehicle  1000  may further include controller  200  and motor  300 , wherein controller  200  is used for controlling battery  100  to power motor  300 , for example, for the operating power demand when vehicle  1000  is starting, navigating, and driving. 
     In some embodiments of the present application, battery  100  not only may serve as an operating power source of vehicle  1000 , but also may serve as a driving power source of vehicle  1000 , thus replacing or partially replacing fuel or natural gas to provide driving power for vehicle  1000 . 
     Referring to  FIG.  2   ,  FIG.  2    is an exploded diagram of battery  100  according to some embodiments of the present application. Battery  100  includes box body  10  and battery cell  20 . Battery cell  20  is accommodated in box body  10 . Here, box body  10  is used for providing an accommodating space for battery cell  20 , and box body  10  may be of various structures. In some embodiments, box body  10  may include first portion  11  and second portion  12 . First portion  11  and second portion  12  cover each other, and first portion  11  and second portion  12  together define an accommodating space for accommodating battery cell  20 . Second portion  12  may be a hollow structure with one end open, first portion  11  may be a plate-like structure, and first portion  11  covers an open side of second portion  12 , so that first portion  11  and second portion  12  together define the accommodating space. First portion  11  and second portion  12  may also be hollow structures with one side open, and the open side of first portion  11  covers the open side of second portion  12 . Of course, box body  10  formed by first portion  11  and second portion  12  may be of various shapes, such as a cylinder and a cuboid. 
     In battery  100 , there may be a plurality of battery cells  20 , and the plurality of battery cells  20  may be connected in series or parallel or be in parallel-series connection, wherein the parallel-series connection means that the plurality of battery cells  20  are connected in both series and parallel. The plurality of battery cells  20  may be directly connected in series or parallel or be in parallel-series connection together, and then, the whole of the plurality of battery cells  20  is accommodated within box body  10 . Of course, battery  100  may also be such that a plurality of battery cells  20  are first connected in series or parallel or in parallel-series connection to form a battery module, and a plurality of battery modules are connected in series or parallel or in parallel-series connection to form a whole and is accommodated within box body  10 . Battery  100  may further include other structures, for example, battery  100  may further include a bus component for electrically connecting the plurality of battery cells  20 . 
     Each battery cell  20  may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. Battery cell  20  may be in the shape of a cylinder, a flat body, a cuboid, or others. 
     Referring to  FIG.  3   ,  FIG.  3    is a schematic three-dimensional structural diagram of battery cell  20  according to some embodiments of the present application. As shown in  FIG.  3    and referring to  FIG.  5   , battery cell  20  includes case  21 , end cover  22 , electrode assembly  23 , terminal post  24 , and other functional components. 
     Case  21  is an assembly that forms an internal environment of battery cell  20 , wherein the formed internal environment may be used for accommodating electrode assembly  23 , the electrolyte solution, and other components. Case  22  may be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, and hexagonal. Specifically, the shape of case  22  may be determined according to the specific shape and size of electrode assembly  23 . Case  22  may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic, which is not particularly limited in the embodiments of the present application. 
     End cover  22  refers to a component that covers an opening of case  21  to isolate the internal environment of battery cell  20  from the external environment. Without limitation, the shape of end cover  22  may be adapted to the shape of case  21  to fit case  21 . Optionally, end cover  22  may be made of a material with certain hardness and strength (such as aluminum alloy), and in this way, end cover  22  is not easily deformed when it is squeezed and collided, so that battery cell  20  can have a higher structural strength and safety performance may also be improved. Functional components such as terminal post  24  may be provided on end cover  21 . Terminal post  24  is used for electrical connection with electrode assembly  23  for outputting or inputting the electric energy of battery cells  20 . In some embodiments, end cover  22  may also be provided with a pressure relief mechanism for releasing an internal pressure when the internal pressure or temperature of battery cell  20  reaches a threshold value. The material of end cover  22  may also be various, such as, copper, iron, aluminum, stainless steel, aluminum alloy, and plastic, which is not particularly limited in the embodiments of the present application. In some embodiments, an insulating member may also be arranged on an inner side of end cover  22 , and the insulating member may be used for isolating electrical connection components in case  21  from end cover  22 , so as to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like. 
     Case  21  and end cover  22  may be separate components. Without limitation, case  21  and end cover  22  may also be integrated. Specifically, case  21  and end cover  22  may form a common connection surface before other components are put into the case. When it is necessary to encapsulate the interior of case  21 , end cover  22  is made to cover case  21 . 
     Electrode assembly  23  is a component in which an electrochemical reaction takes place in battery cell  20 . One or more electrode assemblies  23  may be contained in case  21 . Electrode assembly  23  is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually arranged between the positive electrode sheet and the negative electrode sheet. Portions of the positive electrode sheet and the negative electrode sheet with active materials constitute main body part  231  of the electrode assembly, and portions of the positive electrode sheet and the negative electrode sheet without active materials constitute tabs  232 , respectively. In order to improve the overcurrent capability, tab  232  includes a plurality of tab sheets stacked in layers. During charging and discharging of the battery, the positive active material and the negative active material react with the electrolyte solution, and tabs  232  are connected to terminal post  24  to form a current loop. 
     According to some embodiments of the present application, referring to  FIG.  3    and  FIG.  4   , and further referring to  FIG.  5    to  FIG.  10   ,  FIG.  3    is a schematic three-dimensional structural diagram of battery cell  20  according to some embodiments of the present application.  FIG.  4    is a schematic top-view structural diagram of battery cell  20  shown in  FIG.  3   , and  FIG.  5    is a schematic sectional structural diagram of a battery cell in a direction A-A according to some embodiments of the present application.  FIG.  6    is a schematic partial enlarged structural diagram of a part N in  FIG.  5   .  FIG.  7    is a schematic front-view structural diagram of battery cell  20  shown in  FIG.  3   .  FIG.  8    is a schematic sectional structural diagram of a battery cell in a direction C-C according to some embodiments of the present application.  FIG.  9    is a schematic partial enlarged structural diagram of a part M in  FIG.  8   .  FIG.  10    is a schematic three-dimensional structural diagram of a tab of an electrode assembly according to some embodiments of the present application. 
     The present application provides battery cell  20 . Battery cell  20  includes electrode assembly  23 . Electrode assembly  23  includes main body part  231  and tab  232  extending from main body part  231  to end cover  22  side. Tab  232  is formed by bending a plurality of tab sheets stacked in layers. Tab  232  includes first bending portion  232   a  and straight portion  232   b . Straight portion  232   b  is connected to main body part  231  through first bending portion  232   a . Second bending portion  232   c  is formed at least on straight portion  232   b , and second bending portion  232   c  protrudes towards main body part  231  side. 
     As shown in  FIG.  3   , first direction X in the figure is a length direction of battery cells  20 , second direction Y is a thickness direction of battery cells  20 , and third direction Z is a height direction of battery cells  20 . 
     Referring to  FIG.  4    and  FIG.  5   , electrode assembly  23  includes two tabs  232  protruding from one side of main body part  231 . Two tabs  232  have opposite polarities, and are respectively a positive tab and a negative tab. In other embodiments, two tabs  232  may also protrude from both ends of main body part  231 , respectively. In the embodiment shown in  FIG.  5    and  FIG.  6   , the structures of two tabs  232  are the same, and therefore, for the convenience of description, reference numerals of the two tabs are not distinguished. However, it should be further noted here that in other embodiments, the structure of the negative tab may also be different from that of the positive tab. For example, the positive tab is provided with a second bending portion, while the negative tab is not provided with a second bending portion; or the negative tab is provided with a second bending portion, while the positive tab is not provided with a second bending portion, these are all possible embodiments. In other words, in some embodiments, a second bending portion is formed on the straight portion of at least one tab of the positive tab and the negative tab. 
     The arrangement of second bending portion  232   c  makes a part of tab  232  generate a protruding deformation towards one side of main body part  231 , and this deformation makes the layers of tab  232  close together, forming a local binding of tab  232  and increasing a separation resistance between the layers of tab  232 , thereby avoiding the tab bifurcation and improving the safety of the battery. 
     In the embodiment shown in  FIG.  10   , second bending portion  232   c  is formed on straight portion  232   b . Moreover, second bending portion  232   c  extends on straight portion  232   b , that is, extends from a free end of straight portion  232   b  to a connection of straight portion  232   b  and first bending portion  232   a.    
     According to some embodiments of the present application, second bending portion  232   c  is formed on straight portion  232   b  and first bending portion  232   a . In other words, second bending portion  232   c  extends from straight portion  232   b  to first bending portion  232 . 
     Second bending portion  232   c  is formed on straight portion  232   b  and first bending portion  232   a , so that an area where the tab is bound is larger, thereby further avoiding the tab bifurcation. 
     According to some embodiments of the present application, referring to  FIG.  10   , first bending portion  232   a  has a first bending axis. Second bending portion  232   a  has a second bending axis. The second bending axis and the first bending axis have an included angle or are parallel. 
     Referring to  FIG.  10   , the first bending axis of first bending portion  232   a  extends in first direction X, and bending tab  232  along the first bending axis can reduce the space occupied by tab  232  in the height direction of electrode assembly  23 . In some embodiments, the second bending axis and the first bending axis are parallel to each other, that is, the second bending axis also extends in first direction X. At this time, second bending portion  232   c  on the tab protrudes downward to form a binding on the tab, which increases the separation resistance between the layers of the tab, and avoids the tab bifurcation. In some other embodiments, the second bending axis and the first bending axis have an included angle. For example, the second bending axis is arranged obliquely or perpendicularly with respect to the first bending axis. Second bending portion  232   c  formed in this way makes the layers of the tab converge to the middle of second bending portion  232   c , and the separation resistance is greater, thereby avoiding the tab bifurcation. 
     Referring to  FIG.  10   , in some embodiments, second bending portion  232   c  may be formed by processing the tab by a preforming device before assembling of the battery cell, for example, formed by using a compression molding device to press a part of the tab towards the side of the main body part or by clamping both sides of the tab using a special-shaped clamp. At this time, second bending portion  232   c  on tab  232  is formed by pre-processing, and therefore, the extending direction of tab  232  is not limited. For example, the tab may extend from the main body part to the side of the end cover, or may extend to both ends. 
     In some other embodiments, second bending portion  232   c  is formed in the assembling process of the battery cell, that is, the battery cell includes a pressing-down structure for forming the second bending portion of the tab. 
     According to some embodiments of the present application, referring to  FIG.  5    and  FIG.  6   , battery cell  20  further includes case  21 , end cover  22 , and a pressing-down structure. Case  21  has an opening, and end cover  22  is arranged at the opening to close the opening. Tab  232  extends from main body part  231  to one side of end cover  22 . The pressing-down structure is arranged between tab  232  and end cover  22 . Moreover, the pressing-down structure abuts against tab  232  so that tab  232  forms second bending portion  232   c.    
     The pressing-down structure is arranged between tab  232  and end cover  22 . In other words, the pressing-down structure is arranged above tab  232 , so that after battery cell  20  is assembled, the pressing-down structure can continue to abut against tab  232 . Therefore, the shape of second bending portion  232   c  on tab  232  is maintained continuously, thereby effectively ensuring the continuous converging effect between the various layers of tab sheets of tab  232  and preventing the tab bifurcation. 
     According to some embodiments of the present application, referring to  FIG.  5   , battery cell  20  further includes terminal post  24  arranged on end cover  22  and adapter plate  26 . Adapter plate  26  is configured to connect terminal post  26  and straight portion  232   b  of tab  232 , and the pressing-down structure is arranged at a position where adapter plate  26  cooperates with straight portion  232   b.    
     Specifically, as shown in  FIG.  5   , battery cell  20  includes two terminal posts  24  arranged on end cover  22 . Two terminal posts  24  are respectively connected to two tabs  232  through two adapter plates  26 , respectively. As shown in  FIG.  5    and  FIG.  6   , end portions of two adapter plates  26  are each provided with a pressing-down structure. As shown in  FIG.  6    to  FIG.  10   , the pressing-down structure makes second bending portion  232   c  to be formed on straight portion  232   b  of tab  232 . 
     Adapter plate  26  is a component used for connecting terminal post  24  and tab  232 , and the pressing-down structure is arranged on adapter plate  26  and at the position where adapter plate  26  cooperates with straight portion  232   b . Then, after adapter plate  26  is connected to straight portion  232   b  of tab  232 , the pressing-down structure can naturally form a downward pressing on tab  232 , and therefore, this arrangement simplifies the assembling of battery cell  20 . 
     According to some embodiments of the present application, referring to  FIG.  6   , the pressing-down structure includes protruding portion  261  arranged on the adapter plate. 
     As shown in  FIG.  6   , protruding portion  261  is arranged on a lower surface of adapter plate  26  and protrudes towards the side of the main body part. Protruding portion  261  abuts against the upper surface of tab  232  so that tab  232  forms second bending portion  232   c  facing one side of main body part  231 . 
     According to some embodiments of the present application, the height of protruding portion  261  is 1 mm to 5 mm. 
     The height of protruding portion  262  refers to a distance between the lowermost end of protruding portion  261  and the lower surface of adapter plate  26 . Setting the height of protruding portion  261  within the above range can ensure that the protrusion depth of the second bending portion formed by the tab forms an effective binding between the layers of the tab sheets. If the height of protruding portion  261  is less than 1 mm, the protruding depth of second bending portion  232   c  formed by pressing of protruding portion  261  will be small, and the binding force at this time will also be small, which cannot better prevent the tab bifurcation. If the height of protruding portion  261  is greater than 5 mm, the protruding depth of second bending portion  232   c  formed by the protruding portion  261  will be larger, which may cause second bending portion  232   c  to protrude to a position where second bending portion  232   c  is in contact with main body part  231 , and in this way, a short circuit of contact with main body part  231  may be caused. 
     According to some embodiments of the present application, the height of protruding portion  261  gradually increases in a direction from first bending portion  232   a  to straight portion  232   b.    
     A free end of straight portion  232   b  is easier to disperse, and therefore, in order to make deformation of the free end side of straight portion  232   b  larger to form a larger binding force, the height of protruding portion  261  is set to gradually increase in the direction from first bending portion  232   a  to straight portion  232   b.    
     According to some embodiments of the present application, protruding portion  261  and adapter plate  26  are formed integrally. 
     For example, in the embodiment shown in  FIG.  6   , protruding portion  261  is formed by bending an end portion of first adapter plate  26 . In other embodiments, a protruding portion may be directly formed integrally on the lower surface of the adapter plate when the adapter plate is manufactured. 
     By integrally forming protruding portion  261  and adapter plate  26 , when battery cell  20  is assembled, directly connecting adapter plate  26  and tab  232  can at the same time realize the abutment of protruding portion  261  against tab  232 , so as to form second bending portion  232   c . Therefore, the assembling process of the battery cell can be simplified. 
     According to some embodiments of the present application, protruding portion  261  and adapter plate  26  are separate structures, and protruding portion  261  is connected to adapter plate  26 . Specifically, protruding portion  261  may be connected to adapter plate  26  by adhering or other connection methods. 
     Protruding portion  261  and adapter plate  26  are separate structures, so that the position of protruding portion  261  on adapter plate  26  may be changed according to actual requirements in the assembling process. For example, adapter plate  26  includes a first connection region connected to terminal post  24  and a second connection region connected to tab  232 , then protruding portion  261  may be arranged on one side of the second connection region as required. In other words, at this time, protruding portion  261  and the first connection region are located on two sides of the second connection region. For another embodiment, adapter plate  26  may further include a second connection region and a third connection region that are connected to tab  232  and are arranged at an interval, and therefore, protruding portion  261  may be arranged between the second connection region and the third connection region as required. 
     According to some embodiments of the present application, protruding portion  261  has a contact surface abutting against tab  232 , and the contact surface includes a curved surface. 
     Protruding portion  261  mentioned here has a contact surface abutting against the tab, and the contact surface including a curved surface means that a part abutting against the tab is a curved surface, and the entire surface of the protruding portion may be a curved surface, or may be a partially curved surface with other parts being a plane, or the like. For example, in the embodiment shown in  FIG.  6   , protruding portion  261  is formed by bending the end portion of adapter plate  26  into a U shape. At this time, the lower end of the outer surface of the protruding portion is a curved surface, and the upper end is a plane. In other embodiments, the outer surface of protruding portion  261  may also be a spherical surface. 
     The contact surface directly abuts against tab  232 , and therefore, setting the contact surface as the curved surface can avoid damage to tab  232  when abutting against tab  232 . 
     According to some embodiments of the present application, adapter plate  26  includes a first connection region connected to terminal post  24  and a second connection region connected to tab  232 . The pressing-down structure and the first connection region are located at both sides of the second connection region. 
     Referring to  FIG.  5   , adapter plate  26  extends in the first direction, the first connection region of adapter plate  26  close to a first end is connected to terminal post  24 , and a second end of adapter plate  26  is provided with a pressing-down structure. The second connection region of first adapter plate  26  close to the second end is connected to tab  232 , and in other words, the pressing-down structure and the first connection region are located on both sides of the second connection region. 
     The pressing-down structure and the first connection region are located on both sides of the second connection region, respectively, and in this way, the arrangement of the pressing-down structure has no effect on the connections between adapter plate  26  and terminal post  24  and between the adapter plate and tab  232 . During assembling, the original process is still used for connecting adapter plate  26  to terminal post  24  and to tab  232 , and the pressing-down structure arranged on adapter plate  26  can naturally form pressing against tab  232 . 
     According to some embodiments of the present application, adapter plate  26  includes a first connection region connected to terminal post  24 , and a second connection region and a third connection region connected to tab  232 . The pressing-down structure is located between the second connection region and the third connection region. 
     Adapter plate  26  includes two connection regions that are connected to tab  232  and are arranged at an interval, the two connection regions are respectively the second connection region and the third connection region, and the pressing-down structure is arranged between the second connection region and the third connection region, and therefore, both sides of the pressing-down structure are subject to a connection force between adapter plate  26  and tab  232 . Under the limit of the connection forces on the both sides, the pressing-down structure has a small degree of freedom in a height direction, and therefore, the abutment against the tab can be maintained continuously. 
     In other embodiments in which the tab is processed by a pre-forming device to form a second bending portion, the second bending portion may be arranged at two regions of the tab corresponding to the second connection region and the third connection region. In this way, the degree of freedom of displacement of the second bending portion of the tab in the height direction is small, so that the bending shape thereof may be more effectively maintained. 
     According to some embodiments of the present application, battery cell  20  further includes a terminal post arranged on end cover  22  and adapter plate  26 . Adapter plate  26  is configured to connect the terminal post and the straight portion of the tab, and the pressing-down structure is arranged at positions where adapter plate  26  cooperates with the straight portion and first bending portion  232   c.    
     By arranging the pressing-down structure at the positions where adapter plate  26  cooperates with straight portion  232   b  and first bending portion  232   a , second bending portion  232   c  is formed on straight portion  232   b  and first bending portion  232   a  of the tab, so that an area where the tab is bound is larger, thereby further avoiding the tab bifurcation. 
     Referring to  FIG.  11    to  FIG.  14   , according to some embodiments of the present application, battery cell  20  further includes terminal post  24  arranged on end cover  22  and adapter plate  26 . Adapter plate  26  is configured to connect terminal post  24  and tab  232 , and pressing-down structure  28  is arranged at a position at one side of end cover  22  that faces tab  232  and is not blocked by adapter plate  26 . 
     As shown in  FIG.  11    and  FIG.  12   , battery cell  20  includes case  21 , end cover  22 , electrode assembly  23 , and two terminal posts  24  arranged on end cover  22 . Electrode assembly  23  includes main body part  231  and two tabs  232 . Two tabs  232  have opposite polarities and both protrude from one side of main body part  231 . Both of two tabs  232  are connected to corresponding terminal posts  24  through adapter plate  26  respectively. One side (a lower surface) of end cover  22  facing the tab is provided with a pressing-down structure. As shown in  FIG.  11   , pressing-down structure  28  is arranged at a position that is not blocked by adapter plate  26 . In other words, the pressing-down structure and adapter plate  26  are arranged at an interval, and specifically, the pressing-down structure is arranged on one side of adapter plate  26 . Corresponding to two tabs  232 , the lower surface of end cover  22  is provided with two pressing-down structures. 
     End cover  22  is provided with the pressing-down structure, so that when end cover  22  is installed at the opening of case  21 , the pressing-down structure can press against the tab so that the tab forms the second bending portion. 
     In some embodiments, the pressing-down structure and the end cover are arranged separately. In some other embodiments, the pressing-down structure is integrally arranged with the end cover. 
     In some embodiments, the pressing-down structure is a strip-shaped protrusion arranged on the end cover. 
     According to some embodiments of the present application, referring to  FIG.  10   , in a direction of the first bending axis, the pressing-down structure abuts against a portion of the tab close to the middle of the tab. 
     The pressing-down structure abuts against the portion of the tab close to the middle of the tab, and therefore, in first direction X, second bending portion  232   c  formed by the pressing-down structure is located in the middle of the tab, so that portions of the tab located at both sides of second bending portion  232   c  are subject to more balanced binding forces, and each part of the tab can receive a balanced binding force. 
     According to some embodiments of the present application, battery cell  20  includes two or more electrode assemblies  23  arranged side by side. The pressing-down structure abuts against at least two tabs of the two or more electrode assemblies. 
     Referring to  FIG.  8    and  FIG.  9   , battery cell  20  includes two electrode assemblies  23 . Tabs  232  of two electrode assemblies  23  both extend towards one side of the end cover  22 . As shown in  FIG.  9   , when tabs  232  of two electrode assemblies  23  are bent along the first bending axis, free ends of the straight portions of two tabs  232  are arranged opposite to each other and face the middle of battery cell  20 . Adapter plate  26  is connected to two tabs  232  of two electrode assemblies  23 , and the pressing-down structure on adapter plate  26  abuts against two tabs  232  of two electrode assemblies  23 . As shown in  FIG.  10   , a second bending portion is formed on of two tabs  232  under the abutment of adapter plate  26 . 
     The pressing-down structure abuts against at least two tabs of the two or more electrode assemblies, so that there is no need to provide a special pressing-down structure for each tab, thereby simplifying the assembling process of the battery cell and simplifying the structure of the battery cell. 
     According to some embodiments of the present application, electrode assembly  23  includes a positive tab and a negative tab, and a second bending portion is formed on straight portions of the positive tab and the negative tab, respectively. 
     Referring to  FIG.  5   , two tabs  232  have opposite polarities, and are respectively a positive tab and a negative tab. Moreover, adapter plates  26  correspondingly connected to two tabs  232  are each provided with a pressing-down structure, so that a second bending portion is formed on two tabs  232 , respectively. 
     The second bending portion is formed on the straight portions of the positive tab and the negative tab, respectively, and in this way, the positive tab and the negative tab can be effectively bifurcated, thereby further improving the safety of the battery cell. 
     According to some embodiments of the present application, the present application further provides a battery including the battery cell of any of the above solutions. 
     According to some embodiments of the present application, the present application further provides an electrical apparatus including the battery of any one of the above solutions, the battery being configured to provide electric energy to the electrical apparatus. 
     The electrical apparatus may be any of the aforementioned devices or systems in which the battery is applied. 
     According to some embodiments of the present application, a manufacturing method for a battery cell is further provided in the present application, including the following step of: providing electrode assembly  23 , electrode assembly  23  including main body part  231  and tab  232 , and tab  232  including first bending portion  232   a  and straight portion  232   b . Straight portion  232   b  is connected to main body part  231  through first bending portion  232   a , second bending portion  232   c  is formed at least on straight portion  232   b , and second bending portion  232   c  protrudes towards one side of main body part  231 . 
     The arrangement of second bending portion arranged on the straight portion of the tab makes a part of the tab generate a protruding deformation towards the side of the main body part, and this deformation makes the layers of the tab close together, forming a local binding of the tab, and increasing the resistance to separation between the layers of the tab, thereby avoiding the tab bifurcation, and improving the safety of the battery. 
     According to some embodiments of the present application, referring to  FIG.  15   , the manufacturing method for a battery cell includes the following steps: 
     S 101 : Providing case  21  with an opening and end cover  22 : 
     S 102 : Providing electrode assembly  23 , wherein electrode assembly  23  includes main body part  231  and tab  232 , tab  232  includes first bending portion  232   a  and straight portion  232   b , straight portion  232   b  is connected to main body part  231  through first bending portion  232   a , second bending portion  232   c  is formed at least on straight portion  232   b , and second bending portion  232   c  protrudes towards one side of main body part  231 ; 
     S 103 : Placing electrode assembly  23  in case  21  and making the tab of electrode assembly  23  be located on the side of the opening of case  21 ; and 
     S 104 : Installing end cover  22  at the opening of case  21  to close the opening. 
     The arrangement of second bending portion arranged on the straight portion of the tab makes a part of the tab generate a protruding deformation towards the side of the main body part, and this deformation makes the layers of the tab close together, forming a local binding of the tab, and increasing the resistance to separation between the layers of the tab, thereby avoiding the tab bifurcation, and improving the safety of the battery. 
     Second bending portion  232   c  may be formed by processing the tab by a preforming device before assembling of the battery cell, for example, formed by using a compression molding device to press a part of the tab towards the side of the main body part or by clamping both sides of the tab using a special-shaped clamp. 
     In some other embodiments, second bending portion  232   c  is formed during the assembling of the battery cell. The manufacturing method further includes providing a pressing-down structure, the pressing-down structure is arranged between tab  232  and end cover  22 , and when end cover  22  is installed at the opening of case  21  to close the opening, the pressing-down structure abuts against tab  232  so that tab  232  forms second bending portion  232   c.    
     According to some embodiments of the present application, the manufacturing method further includes providing terminal post  24  and adapter plate  26 , connecting a first end of adapter plate  26  to terminal post  24 , arranging the pressing-down structure at a second end of adapter plate  26 , and abutting the pressing-down structure against tab  232 . 
     According to some embodiments of the present application, the manufacturing method further includes disposing the pressing-down structure on end cover  22 , and installing end cover  22  at the opening of case  21  so that the pressing-down structure abuts against tab  232 . 
     The structure of the battery cell according to the specific embodiment of the present application will be described in detail below according to  FIG.  3    to  FIG.  14   . 
       FIG.  3    to  FIG.  10    show the structure of a battery cell according to a specific embodiment of the present application. 
     As shown in  FIG.  3    to  FIG.  5   , in this embodiment, battery cell  20  includes case  21 , end cover  22 , electrode assembly  23 , terminal post  24 , and adapter plate  26 . Case  21  is a square case with an opening, and end cover  22  is arranged at the opening of case  21  to close case  21 . End cover  22  is provided with two terminal posts  24  and. Electrode assembly  23  is accommodated in case  21 . Electrode assembly  23  includes main body part  231  and tab  232  extending from main body part  231  to end cover  22  side. Adapter plate  26  is connected to terminal post  24  and tab  232 . 
     As shown in  FIG.  5    and  FIG.  6   , an end portion of adapter plate  26  is provided with protruding portion  261  that forms a pressing-down structure. Protruding portion  261  is formed by bending the end portion of adapter plate  26 . In other words, protruding portion  261  and adapter plate  26  are formed integrally. 
     As shown in  FIG.  7    to  FIG.  9   , battery cell  20  includes two electrode assemblies  23  arranged side by side in case  21 . Adapter plate  26  is connected to tabs  232  of two electrode assemblies  23  at the same time. Moreover, as shown in  FIG.  10   , protruding portion  261  on adapter plate  26  abuts against straight portions  232   b  of two tabs  232  of two electrode assemblies  23  at the same time, so that straight portions  232   b  of two tabs  232  each form second bending portion  232   c.    
     Adapter plate  26  is a component configured to connect terminal post  24  and tab  232 , then after adapter plate  26  is connected to straight portion  232   b  of tab  232 , protruding portion  261  may naturally form a downward pressing on tab  232 , so that the tab forms second bending portion  232   c . The arrangement of second bending portion  232   c  makes a part of tab  232  generate a protruding deformation towards one side of main body part  231 , and this deformation makes the layers of tab  232  close together, forming a local binding of tab  232  and increasing a separation resistance between the layers of tab  232 , thereby avoiding the tab bifurcation and improving the safety of the battery. Moreover, arranging the pressing-down structure on the adapter plate makes the assembling of battery cell  20  simple. 
     A manufacturing method for a battery cell according to this embodiment includes the following steps: 
     providing case  21  with an opening, end cover  22 , terminal post  24 , and adapter plate  26 ; 
     providing electrode assembly  23 , wherein electrode assembly  23  includes main body part  231  and tab  232 , placing electrode assembly  23  in case  21 , connecting adapter plate  26  to tab  232 , and bending tab  232  along a first bending axis after the connection, wherein after the bending, tab  232  includes first bending portion  232   a  and straight portion  232   b , and straight portion  232   b  is connected to main body part  231  through first bending portion  232   a;    
     after bending, forming, a protruding portion arranged on adapter plate  26 , pressing abutment against straight portion  232   b  so that second bending portion  232   c  is formed on straight portion  232   b , second bending portion  232   c  protruding towards one side of main body part  231 ; and 
     installing end cover  22  at the opening of case  21  to close the opening. 
       FIG.  11    to  FIG.  14    show the structure of a battery cell according to another embodiment of the present application. 
     The external structure of the battery cell of this embodiment is the same as that of the previous embodiment, so it is not shown repeatedly. Therefore, reference may be made to  FIG.  3   ,  FIG.  4   , and  FIG.  7   ,  FIG.  11    is a sectional diagram in a direction A-A in  FIG.  4   , and  FIG.  13    is a sectional diagram in a direction C-C in  FIG.  7   . 
     As shown in  FIG.  11   , a difference from the previous embodiment is that the pressing-down structure of this embodiment is arranged on end cover  22 . Specifically, as shown in  FIG.  12   , protruding portion  221  is arranged on one side of end cover  22  facing tab  232 . Protruding portion  221  is set at a position that is not blocked by adapter plate  26 , so that when end cover  22  is installed, protruding portion  221  may be directly pressed against the straight portion of tab  232  so that the straight portion of tab  232  forms second bending portion  232   c.    
     Similarly, as shown in  FIG.  13    and  FIG.  14   , the battery cell includes two electrode assemblies  23 , and two electrode assemblies  23  are arranged in case  21  side by side. Moreover, protruding portion  221  may press against tab  232  of two electrode assemblies  23  at the same time, so that two tabs  232  each form second bending portion  232   c  at the same time. 
     Specifically, protruding portion  221  is a strip-shaped protrusion arranged on a lower surface of end cover  22 , and a cross-sectional shape of protruding portion  221  is a semicircle. 
     A manufacturing method for a battery cell according to this embodiment includes the following steps: 
     providing case  21  with an opening, end cover  22 , terminal post  24 , and adapter plate  26 ; 
     providing electrode assembly  23 , wherein electrode assembly  23  includes main body part  231  and tab  232 , placing electrode assembly  23  in case  21 , connecting adapter plate  26  to tab  232 , and bending tab  232  along a first bending axis after the connection, wherein after the bending, tab  232  includes first bending portion  232   a  and straight portion  232   b , and straight portion  232   b  is connected to main body part  231  through first bending portion  232   a ; and 
     installing end cover  22  at the opening of case  21  to close the opening, and making protruding portion  221  on end cover  22  to form pressing abutment against straight portion  232   b  so that second bending portion  232   c  is formed on straight portion  232   b , second bending portion  232   c  protruding towards one side of main body part  231 . 
     Finally, it should be noted that the above examples are merely used for illustrating rather than limiting the technical solutions of the present application. Although the present application has been described in detail with reference to the above various examples, those of ordinary skill in the art should understand that the technical solutions specified in the above various examples can still be modified, or some or all of the technical features therein can be equivalently substituted; and such modifications or substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the various examples of the present application, which shall fall within the scope of the claims and the specification of the present application. In particular, the technical features mentioned in the various examples can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific examples disclosed herein, but rather includes all technical solutions falling within the scope of the claims.