Battery cell, battery and electrical device

Abstract

The present application belongs to the technical field of batteries. Disclosed are a battery cell, a battery and an electrical device. Provided in the present application is a battery cell, the battery cell comprising a housing, electrode terminals, electrode assemblies and current collecting members, wherein the electrode terminals are arranged on a wall of the housing; the electrode assemblies are accommodated inside the housing, and each electrode assembly comprises a tab; and the current collecting members are arranged inside the housing, the current collecting members and the electrode terminals are welded to form a first weld mark, and the current collecting members and the tabs are welded to form second weld marks. In the thickness direction of the current collecting members, a projection of the first weld mark on a first plane is a first projection, projections of the second weld marks on the first plane are second projections, and the first plane is perpendicular to the thickness direction of the current collecting members. The first projection and the second projections at least partially overlap in a first direction, which is beneficial to prolonging the cycle life of the battery cell.

Description

Battery cells, batteries and electrical equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application No. 202420157957.6, filed on January 23, 2024, entitled “Battery Cell, Battery and Electrical Equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0003] 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.

[0004] How to improve the cycle life of battery cells is an urgent problem to be solved in battery technology. Summary of the Invention

[0005] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can improve the cycle life of the battery cell.

[0006] In a first aspect, the present application provides a battery cell comprising a housing, electrode terminals, an electrode assembly, and a current collecting member. The electrode terminals are disposed on a wall portion of the housing. The electrode assembly is housed within the housing and includes a tab. The current collecting member is disposed within the housing. The current collecting member is welded to the electrode terminals to form a first weld mark, and the current collecting member is welded to the tab to form a second weld mark. Along the thickness direction of the current collecting member, the projection of the first weld mark onto a first plane is referred to as the first projection, and the projection of the second weld mark onto the first plane is referred to as the second projection. The first plane is perpendicular to the thickness direction of the current collecting member. The first projection and the second projection at least partially overlap along a first direction, which is the thickness direction of the electrode assembly.

[0007] In the technical solution of the embodiment of the present application, the first projection and the second projection at least partially overlap in the first direction, which is beneficial to shortening the current path between the first weld mark and the second weld mark when the battery cell is working, reducing the internal resistance of the battery cell, increasing the voltage of the battery cell, reducing the temperature rise of the battery cell, and thereby improving the cycle life of the battery cell.

[0008] In one or more embodiments of the first aspect, two second weld marks are provided, and the two second weld marks are spaced apart along the first direction, with the first weld mark being located between the two second weld marks.

[0009] In the above solution, since the first weld mark is located between the two second weld marks, the current path between the first weld mark and the two second weld marks is shortened, which can further reduce the internal resistance of the battery cell, further increase the voltage of the battery cell, further reduce the temperature rise of the battery cell, and further improve the cycle life of the battery cell.

[0010] In one or more embodiments of the first aspect, the current collecting component includes a first connection portion and two second connection portions, the two second connection portions are arranged along a first direction, the first connection portion is located between the two second connection portions, the first connection portion is welded to the electrode terminal to form a first weld mark, and the second connection portion is welded to the tab to form a second weld mark.

[0011] In the above solution, the first connecting portion and the second connecting portion can serve as an assembly base for forming the first weld mark and the second weld mark, making it more convenient to weld and position the current collector component, which is conducive to simplifying the assembly process.

[0012] In one or more embodiments of the first aspect, in the second direction, a size of the second connection portion is smaller than a size of the first connection portion, and the first direction, the second direction, and a thickness direction of the current collecting member are perpendicular to each other.

[0013] In the above solution, the size of the second connection part is smaller than that of the first connection part, which means that the flow cross-sectional area at the location where the second connection part is connected to the first connection part will become smaller. When the battery cell thermally runs away, the location where the second connection part and the first connection part are connected can be melted in time, which is beneficial to improving the reliability of the battery cell.

[0014] In one or more embodiments of the first aspect, the current collecting component further includes a transition portion, which connects the first connecting portion and the second connecting portion. In the second direction, the size of the transition portion is smaller than the size of the first connecting portion, and the size of the transition portion is smaller than the size of the second connecting portion. The first direction, the second direction and the thickness direction of the current collecting component are perpendicular to each other.

[0015] In the above solution, the cross-sectional area of ​​the transition portion is smaller than that of the first connection portion and the second connection portion. When the battery cell thermally runs away, the transition portion can be melted in time, which is beneficial to improving the reliability of the battery cell.

[0016] In one or more embodiments of the first aspect, the current collecting member further includes a first positioning portion, which is provided at one end of the first connecting portion in the second direction, and the first direction, the second direction and the thickness direction of the current collecting member are perpendicular to each other.

[0017] In the above solution, during the production process of the battery cell, the first positioning portion can cooperate with the positioning tool to limit the position of the current collecting component in the first direction, which is beneficial to improving the welding accuracy of the current collecting component and simplifying the welding process.

[0018] In one or more embodiments of the first aspect, the first connecting portion includes a first edge and a second edge arranged opposite to each other along the second direction, and the first positioning portion includes two first sub-positioning portions, the two first sub-positioning portions are arranged at intervals along the first direction, and each first sub-positioning portion extends from the first edge in a direction away from the second edge.

[0019] In the above solution, during the production process of the battery cell, the two first sub-positioning portions cooperate with the positioning tool to further improve the positioning accuracy of the current collecting component, which is beneficial to further improve the welding accuracy of the current collecting component.

[0020] In one or more embodiments of the first aspect, the current collecting member further includes a second positioning portion, which is provided at the other end of the first connecting portion in the second direction, and the first direction, the second direction and the thickness direction of the current collecting member are perpendicular to each other.

[0021] In the above solution, the first positioning portion and the second positioning portion are respectively located at the two ends of the first connecting portion in the second direction. The first positioning portion and the second positioning portion cooperate with the positioning tooling to limit the tendency of the current collecting component to rotate during welding, which is beneficial to further improve the welding accuracy of the current collecting component.

[0022] In one or more embodiments of the first aspect, the first connecting portion includes a first edge and a second edge disposed opposite to each other along the second direction, the second positioning portion extends from the second edge in a direction away from the first edge, and a notch is provided at one end of the second positioning portion away from the first connecting portion.

[0023] In the above solution, during the cooperation between the current collecting component and the positioning fixture, the setting of the notched corners can reduce the risk of pre-assembly errors of the current collecting component, which is conducive to improving the production efficiency of battery cells.

[0024] In one or more embodiments of the first aspect, the first connecting portion has a first surface facing the electrode terminal. The current collecting member includes two transition portions, one disposed at each end of the first connecting portion in the first direction, the other connecting portion connecting the first connecting portion and the second connecting portion, and both the transition portions and the second connecting portion protrude from the first surface.

[0025] In the above scheme, the second connecting portion and the transition portion both protrude from the first surface, which means that in the thickness direction of the current collecting component, there is space for accommodating the electrode ear between the first connecting portion and the second connecting portion, which is beneficial to increasing the volume share of the electrode assembly in the battery cell, and further beneficial to increasing the volume energy density of the battery cell.

[0026] In a second aspect, the present application provides a battery comprising the battery cell according to one or more embodiments of the first aspect.

[0027] In the above solution, since the battery cell in the first aspect has a relatively long cycle life, a battery including the battery cell in one or more embodiments of the first aspect also has a relatively long cycle life.

[0028] In a third aspect, the present application provides an electrical device, which includes a battery cell in one or more embodiments of the first aspect, and the battery cell is used to provide electrical energy; or, the electrical device includes a battery in one or more embodiments of the second aspect, and the battery is used to provide electrical energy.

[0029] In the above solution, since the battery cell in the first aspect has a long cycle life, the electrical equipment including the battery cell in one or more embodiments of the first aspect also has a long service life. Since the battery in the second aspect has a long cycle life, the electrical equipment including the battery in one or more embodiments of the second aspect also has a long service life.

[0030] 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, which can be implemented in accordance with the contents of the specification, and to make 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

[0031] 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:

[0032] FIG1 is a schematic structural diagram of a vehicle according to some embodiments of the present application;

[0033] FIG2 is an exploded view of a battery according to some embodiments of the present application;

[0034] FIG3 is an exploded view of a battery cell according to some embodiments of the present application;

[0035] FIG4 is a top view of a partial structure of a battery according to some embodiments of the present application;

[0036] FIG5 is a side view of a partial structure of a battery according to some embodiments of the present application;

[0037] FIG6 is a top view of a partial structure of a battery according to some other embodiments of the present application;

[0038] FIG7 is a top view of a portion of the structure of batteries according to other embodiments of the present application;

[0039] FIG8 is a schematic diagram of the assembly of a partial structure of a battery according to some embodiments of the present application.

[0040] The accompanying drawings in the specific implementation manner are as follows:

[0041] 1000-Vehicle; 200-Controller; 300-Motor; 400-Positioning tooling; 100-Battery; 11-Box; 111-First part; 112-Second part; 12-Battery cell; 120-First plane; 121-Casing; 1211-End cap; 1212-Casing; 122-Electrode assembly; 1221-Electrode tab; 123-Electrode terminal; 124-Current collecting member; 1241-First connecting portion; 12411- First edge; 12412-second edge; 12413-first surface; 1242-second connecting portion; 1243-transition portion; 1244-first positioning portion; 12441-first sub-positioning portion; 1245-second positioning portion; 12451-missing corner; 125-first weld mark; 1250-first projection; 126-second weld mark; 1260-second projection; X-first direction; Y-second direction; Z-thickness direction of the current collecting component. DETAILED DESCRIPTION

[0042] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments 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 figure descriptions are intended to cover non-exclusive inclusions.

[0044] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0045] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may 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 does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0046] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "length", "width", "thickness", "up", "down", "front", "back", "left", and "right" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0047] In this application, battery cells may include, but are not limited to, lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries. The shape of a battery cell may include, but is not limited to, a cylinder, a flat body, a rectangular parallelepiped, or other shapes. Battery cells, depending on the packaging method, may include, but are not limited to, cylindrical battery cells, prismatic battery cells, soft-pack battery cells, and blade battery cells.

[0048] In some high-power applications such as electric vehicles, the application of batteries includes three levels: battery cells, battery modules and batteries. The battery module is formed by electrically connecting a certain number of battery cells together and placing them in a frame in order to protect the battery cells from external impact, heat, vibration, etc. The battery refers to the final state of the battery system installed in the electric vehicle. The battery mentioned in the embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. The battery generally includes a box for encapsulating one or more battery cells. The box can reduce the risk of liquid or other foreign matter affecting the charging or discharging of the battery cells.

[0049] The following will mainly focus on rectangular parallelepiped battery cells. It should be understood that the embodiments described below are also applicable to cylindrical battery cells, soft-pack battery cells, or blade battery cells in some aspects.

[0050] In a typical battery cell structure, the battery cell includes a housing, an electrode assembly, and an electrolyte. The housing includes an end cap and a shell, wherein the end cap closes an opening of the shell to define a receiving space for receiving the electrode assembly.

[0051] The electrode assembly is housed in the housing. It includes a positive electrode sheet, a negative electrode sheet, and a separator. Battery cells primarily operate by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The uncoated positive electrode collector protrudes from the coated positive electrode collector, serving as the positive electrode tab. For lithium-ion batteries, for example, the positive electrode collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The uncoated negative electrode collector protrudes from the coated negative electrode collector, serving as the negative electrode tab. The negative electrode collector can be made of copper, and the negative electrode active material can be carbon, silicon, or other materials. In order to pass high current without melting, the number of positive tabs is multiple and stacked together, and the number of negative tabs is multiple and stacked together. In addition, the electrode assembly can be formed in a manner including but not limited to winding or lamination.

[0052] The tabs generally lead out the electrical energy of the electrode assembly by being electrically connected to the conductive member. In some cases, the conductive member is a current collecting component connecting the tabs and the electrode terminals.

[0053] Electrode terminals generally include positive and negative terminals. For rectangular battery cells, electrode terminals are typically located in the end caps. In some other cases, electrode terminals may also be located in the housing. Multiple battery cells can be connected in series and / or in parallel via the electrode terminals for various applications.

[0054] The development of battery technology must take into account multiple design factors at the same time, such as reliability, energy density, discharge capacity, charge and discharge rate and other performance parameters. In addition, the battery cycle life must also be considered.

[0055] In a battery cell, the electrode assembly's tabs are typically welded to the current collecting member for electrical connection, and the electrode terminals are typically welded to the current collecting member for electrical connection. This allows current to flow from the electrode assembly through the current collecting member to the electrode terminals, where it can be drawn out of the battery cell. During normal operation, the long current path through the current collecting member creates a high internal resistance, resulting in low voltage, high temperature rise, and a shorter cycle life.

[0056] In view of this, the present application provides a battery cell, which includes a housing, electrode terminals, an electrode assembly, and a current collecting member, wherein the electrode terminals are disposed on the wall of the housing. The electrode assembly is housed within the housing and includes a tab. The current collecting member is disposed within the housing, and the current collecting member is welded to the electrode terminal to form a first weld mark, and the current collecting member is welded to the tab to form a second weld mark. In this regard, along the thickness direction of the current collecting member, the projection of the first weld mark on a first plane is the first projection, and the projection of the second weld mark on the first plane is the second projection, and the first plane is perpendicular to the thickness direction of the current collecting member. The first projection and the second projection at least partially overlap along a first direction, which is the thickness direction of the electrode assembly. The at least partial overlap of the first projection and the second projection in the first direction facilitates shortening the current path between the first weld mark and the second weld mark during operation of the battery cell, reducing the internal resistance of the battery cell, increasing the voltage of the battery cell, reducing the temperature rise of the battery cell, and thereby improving the cycle life of the battery cell.

[0057] The technical solutions described in the embodiments of the present application are applicable to battery cells, batteries, and electrical equipment using batteries.

[0058] Electrical equipment includes, but is not limited to, battery vehicles, electric vehicles, ships, and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.

[0059] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0060] For example, FIG1 is a schematic diagram of the structure of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. A motor 300, a controller 200, and a battery 100 may be provided inside the vehicle 1000. The controller 200 is used to control the battery 100 to power the motor 300. For example, the battery 100 may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as the operating power source of the vehicle 1000 and may be used for the circuit system of the vehicle 1000, such as for the starting, navigation, and operation power requirements of the vehicle 1000. In another embodiment of the present application, the battery 100 may serve not only as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0061] To meet different power requirements, the battery 100 may include multiple battery cells 12, wherein the multiple battery cells 12 can be connected in series, in parallel, or in a hybrid connection. Hybrid connection refers to a mixture of series and parallel connections. The battery 100 may also be referred to as a battery pack. Optionally, multiple battery cells 12 may first be connected in series, in parallel, or in a hybrid connection to form a battery module, and multiple battery modules may then be connected in series, in parallel, or in a hybrid connection to form the battery 100. In other words, multiple battery cells 12 may directly form the battery 100, or they may first form battery modules, which may then form the battery 100.

[0062] For example, referring to FIG. 2 , FIG. 2 is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 may include a plurality of battery cells 12. The battery 100 may also include a housing 11 having a hollow interior, and the plurality of battery cells 12 are housed within the housing 11. As shown in FIG. 2 , these are referred to herein as a first portion 111 and a second portion 112, respectively. The first portion 111 and the second portion 112 are fastened together. The shapes of the first portion 111 and the second portion 112 may be determined based on the combined shape of the plurality of battery cells 12. The first portion 111 and the second portion 112 may each have a single opening. For example, the first portion 111 and the second portion 112 may each be a hollow rectangular parallelepiped, each with only one open face. The opening of the first portion 111 and the opening of the second portion 112 are arranged opposite each other, and the first portion 111 and the second portion 112 are fastened together to form the housing 11 having a closed chamber. The plurality of battery cells 12 are then arranged in parallel, in series, or in a mixed configuration and then placed within the housing 11 formed by the fastening of the first portion 111 and the second portion 112.

[0063] Optionally, the battery 100 may also include other structures, which will not be described in detail here. For example, the battery 100 may also include a busbar component, which is used to achieve electrical connection between multiple battery cells 12, such as parallel connection, series connection, or mixed connection. Specifically, the busbar component can achieve electrical connection between the battery cells 12 by connecting the electrode terminals 123 of the battery cells 12. Furthermore, the busbar component can be fixed to the electrode terminals 123 of the battery cells 12 by welding. The electrical energy of the multiple battery cells 12 can be further led out through the box 11 through the conductive mechanism.

[0064] The number of battery cells 12 can be set to any value according to different power requirements. Multiple battery cells 12 can be connected in series, parallel, or in a hybrid manner to achieve a larger capacity or power. Since the number of battery cells 12 included in each battery 100 may be large, for ease of installation, the battery cells 12 can be grouped, and each group of battery cells 12 constitutes a battery module. The number of battery cells 12 included in a battery module is not limited and can be set according to requirements. The battery 100 may include multiple battery modules, which can be connected in series, parallel, or in a hybrid manner.

[0065] Please refer to Figure 3, which is an exploded view of a battery cell 12 in some embodiments of the present application. The battery cell 12 includes one or more electrode assemblies 122 and a shell 121. The shell 121 may include a housing 1212. The multiple walls of the housing 1212, i.e., the multiple walls of the housing 121, form a cavity, which can be used to accommodate the electrode assembly 122. The housing 1212 is determined according to the shape of the one or more electrode assemblies 122 after being combined. For example, the housing 1212 can be a hollow cuboid, a cube, or a regular polyhedron, and one of the faces of the housing 1212 has an opening so that one or more electrode assemblies 122 can be placed in the housing 1212. The housing 1212 is filled with an electrolyte, such as an electrolyte solution.

[0066] The battery cell 12 may also include two electrode terminals 123, which may be provided on the end cap 1211. The end cap 1211 is generally in the shape of a flat plate, and the two electrode terminals 123 are fixed to the flat surface of the end cap 1211. The two electrode terminals 123 are respectively a positive electrode terminal 123 and a negative electrode terminal 123. Referring to FIG3 , in some embodiments, a current collecting member 124 is provided for each electrode terminal 123, which is located between the end cap 1211 and the electrode assembly 122 and is used to electrically connect the electrode assembly 122 and the electrode terminal 123. In the battery cell 12, the electrode assembly 122 may be provided as a single one or multiple ones according to actual use requirements. A plurality of independent electrode assemblies 122 are provided in the battery cell 12.

[0067] According to some embodiments of the present application, referring to FIG. 3 and FIG. 4 , a battery cell 12 is provided. The battery cell 12 includes a housing 121, an electrode terminal 123, an electrode assembly 122, and a current collecting member 124. The electrode terminal 123 is disposed on a wall of the housing 121. The electrode assembly 122 is housed within the housing 121 and includes a tab 1221. The current collecting member 124 is disposed within the housing 121. The current collecting member 124 is welded to the electrode terminal 123 to form a first weld mark 125. The current collecting member 124 is welded to the tab 1221 to form a second weld mark 126. Along the thickness direction Z of the current collecting member, the projection of the first weld mark 125 onto a first plane 120 is a first projection 1250, and the projection of the second weld mark 126 onto the first plane 120 is a second projection 1260. The first plane 120 is perpendicular to the thickness direction Z of the current collecting member. The first projection 1250 and the second projection 1260 at least partially overlap along the first direction X, where the first direction X is the thickness direction of the electrode assembly 122 .

[0068] The shape of the current collecting member 124 can be a flat plate or a special shape, such as a Z shape, a U shape, or an I shape.

[0069] The housing 121 generally has a receiving cavity, and the electrode assembly 122 is accommodated in the housing 121. The electrode terminal 123 can be provided on any wall of the housing 1212. In some embodiments, the housing 121 includes an end cap 1211 and a housing 1212, and the electrode terminal 123 can be provided on the end cap 1211 or on any wall of the housing 1212.

[0070] The electrode assembly 122 generally includes a main body and tabs 1221. The electrode assembly 122 is typically formed by stacking or winding multiple electrode sheets. The main body generally has an active material layer, while the tabs 1221 are not coated with the active material layer. The tabs 1221 can include positive and negative tabs. The positive tab can be made of aluminum, for example, and the negative tab can be made of copper, for example. The electrode assembly 122 is generally flat.

[0071] The current collecting member 124 and the electrode terminal 123 can be welded to form a first weld mark 125 using ultrasonic, laser, or other welding methods. The current collecting member 124 and the electrode tab 1221 can also be welded to form a second weld mark 126 using ultrasonic, laser, or other welding methods. In some embodiments, the current collecting member 124 and the electrode tab 1221 are ultrasonically welded to form the second weld mark 126, while the current collecting member 124 and the electrode terminal 123 are laser welded to form the first weld mark 125. The high power of laser welding can improve the assembly efficiency of the current collecting member 124. Ultrasonic welding allows for more precise control of weld formation, reducing the risk of damage to the electrode tab 1221 during the welding process. In embodiments where laser welding is used to weld the current collecting member 124 and the electrode assembly 122, the surface of the current collecting member 124 where the weld is formed is typically provided with protrusions or holes to reduce the risk of laser reflection.

[0072] Referring to Figures 3 and 5 , first plane 120 is a reference plane and does not represent the physical surface of the product. Along the thickness direction of the current collector, first projections 1250 and 1260 of first weld mark 125 and second weld mark 126 falling on the same plane, first plane 120, at least partially overlap in the first direction X. This means that the current path from second weld mark 126 to first weld mark 125 is shorter.

[0073] In some embodiments, referring to FIG. 4 , the maximum dimension of the first weld mark 125 in the second direction Y is J, the maximum dimension of the second weld mark 126 in the second direction Y is H, and the dimension of the overlapping portion of the first projection 1250 and the second projection 1260 along the first direction X is K, where K satisfies: 0≤K≤min(J,H). For example, in some embodiments, if J=15 mm and H=16 mm, then 0≤K≤15 mm.

[0074] In the technical solution of the embodiment of the present application, the first projection 1250 and the second projection 1260 at least partially overlap in the first direction X, which is beneficial for shortening the current path between the first weld mark 125 and the second weld mark 126 when the battery cell 12 is working, reducing the internal resistance of the battery cell 12, increasing the voltage of the battery cell 12, reducing the temperature rise of the battery cell 12, and thereby improving the cycle life of the battery cell 12.

[0075] According to some embodiments of the present application, referring to FIG. 4 and FIG. 5 , two second weld marks 126 are provided. Along the first direction X, the two second weld marks 126 are spaced apart, and the first weld mark 125 is located between the two second weld marks 126 .

[0076] In some embodiments, a plurality of electrode assemblies 122 may be provided in the battery cell 12 , and the two second weld marks 126 may be adapted to electrically connect different electrode assemblies 122 with the current collecting member 124 .

[0077] Along the first direction X, the first weld mark 125 is located between the two first weld marks 125 , and the first projection 1250 and the second projection 1260 at least partially overlap, which means that the current paths between the two second weld marks 126 and the first weld mark 125 are relatively short.

[0078] In the above scheme, since the first weld mark 125 is located between the two second weld marks 126, the current path between the first weld mark 125 and the two second weld marks 126 is shortened, which can further reduce the internal resistance of the battery cell 12, further increase the voltage of the battery cell 12, further reduce the temperature rise of the battery cell 12, and further improve the cycle life of the battery cell 12.

[0079] According to some embodiments of the present application, please refer to Figures 4 and 5. The current collecting member 124 includes a first connection portion 1241 and two second connection portions 1242. The two second connection portions 1242 are arranged along the first direction X. The first connection portion 1241 is located between the two second connection portions 1242. The first connection portion 1241 is welded to the electrode terminal 123 to form a first weld mark 125. The second connection portion 1242 is welded to the tab 1221 to form a second weld mark 126.

[0080] The current collecting member 124 includes a first connecting portion 1241 and two second connecting portions 1242. This means that during welding of the current collecting member 124 to the electrode terminal 123 and the tab 1221, both the tab 1221 and the electrode terminal 123 have specific connecting portions, facilitating the positioning of the current collecting member 124 during welding. In some embodiments, referring to FIG4 , the shorter portion in the second direction Y is the second connecting portion 1242, while the longer portion is the first connecting portion 1241. Referring to FIG5 , in the first direction X, the left and right ends of the current collecting member 124 are the second connecting portions 1242, while the middle portion of the current collecting member 124 is the first connecting portion 1241. The second connecting portions 1242 protrude beyond the surface of the first connecting portion 1241 in the thickness direction of the current collecting member 124. In other embodiments, referring to FIG7 , the shorter portion in the first direction X is the second connecting portion 1242, while the longer portion is the first connecting portion 1241.

[0081] The first connection portion 1241 and the second connection portion 1242 may be integrally formed or separately formed.

[0082] In the above solution, the first connection portion 1241 and the second connection portion 1242 can serve as an assembly base for forming the first weld mark 125 and the second weld mark 126 , making it more convenient to weld and position the current collector component, thereby simplifying the assembly process.

[0083] According to some embodiments of the present application, referring to FIG. 4 and FIG. 6 , in the second direction Y, the size of the second connection portion 1242 is smaller than that of the first connection portion 1241 , and the first direction X, the second direction Y and the thickness direction Z of the current collecting member are perpendicular to each other.

[0084] The size of the second connection part 1242 is smaller than that of the first connection part 1241, which means that there is a part with reduced flow cross-sectional area at the position where the first connection part 1241 and the second connection part 1242 are connected. The size of the second connection part 1242 is smaller than that of the first connection part 1241, which means that the flow cross-sectional area at the position where the second connection part 1242 is connected to the first connection part 1241 will become smaller. When the battery cell 12 thermally runs away, the position where the second connection part 1242 and the first connection part 1241 are connected can be fused in time.

[0085] 4 and 6 , in the second direction Y, the size of the second connection portion 1242 is smaller than that of the first connection portion 1241 , which is equivalent to the presence of a cutout on one or both sides of the second weld mark 126 on the current collecting component 124 . The shape of the cutout may include but is not limited to a rectangle, a ring, or an arc.

[0086] In the above solution, the size of the second connection portion 1242 is smaller than that of the first connection portion 1241 , which is beneficial to improving the reliability of the battery cell 12 .

[0087] According to some embodiments of the present application, please refer to Figures 4 and 7. The current collecting component 124 also includes a transition portion 1243, which connects the first connection portion 1241 and the second connection portion 1242. In the second direction Y, the size of the transition portion 1243 is smaller than the size of the first connection portion 1241, and the size of the transition portion 1243 is smaller than the size of the second connection portion 1242. The first direction X, the second direction Y and the thickness direction Z of the current collecting component are perpendicular to each other.

[0088] The transition portion 1243 connects the first connection portion 1241 and the second connection portion 1242. In the second direction Y, the size of the transition portion 1243 is smaller than that of the first connection portion 1241, and the size of the transition portion 1243 is smaller than that of the second connection portion 1242. This means that the cross-sectional area of ​​the transition portion 1243 is small, allowing the transition portion 1243 to fuse promptly in the event of thermal runaway of the battery cell 12. In other words, the transition portion 1243 is located in the current flow path between the tab 1221 and the electrode terminal 123.

[0089] 7 , the transition portion 1243 may be formed by opening a hole or a groove on the current collecting member 124 .

[0090] In the above solution, the cross-sectional area of ​​the transition portion 1243 is smaller than that of the first connection portion 1241 and the second connection portion 1242 . When the battery cell 12 experiences thermal runaway, the transition portion 1243 can be promptly melted, thereby improving the reliability of the battery cell 12 .

[0091] According to some embodiments of the present application, referring to Figures 4, 5 and 8, the current collecting component 124 also includes a first positioning portion 1244, which is arranged at one end of the first connecting portion 1241 in the second direction Y, and the first direction X, the second direction Y and the thickness direction Z of the current collecting component are perpendicular to each other.

[0092] Referring to Figure 8 , during the production process of the battery cell 12, the current collecting member 124, after processing, needs to be welded to the electrode terminal 123 and the tab 1221. At this point, a positioning fixture 400 is typically used to pre-position the current collecting member 124 to allow for precise welding. A first positioning portion 1244 is provided at one end of the first connecting portion 1241 in the second direction Y. This means that the first positioning portion 1244 cooperates with the positioning fixture 400 to limit the position of the current collecting member 124 in the first direction X.

[0093] The first positioning portion 1244 may be integrally formed with the first connecting portion 1241 or may be separately formed from the first connecting portion 1241 .

[0094] The first positioning portion 1244 may be a boss, a groove, a circular hole, etc. provided on the first connecting portion 1241 .

[0095] In some embodiments, the first positioning portion 1244 , the first connecting portion 1241 , and the second connecting portion 1242 are integrally formed.

[0096] In the above solution, the first positioning portion 1244 can cooperate with the positioning tool 400 to limit the position of the current collecting component 124 in the first direction X, which is beneficial to improving the welding accuracy of the current collecting component 124 and simplifying the welding process.

[0097] According to some embodiments of the present application, please refer to Figures 4, 5 and 8, the first connecting portion 1241 includes a first edge 12411 and a second edge 12412 arranged opposite to each other along the second direction Y, and the first positioning portion 1244 includes two first sub-positioning portions 12441, and the two first sub-positioning portions 12441 are arranged at intervals along the first direction X, and each first sub-positioning portion 12441 extends from the first edge 12411 in a direction away from the second edge 12412.

[0098] The shape of the first sub-positioning portion 12441 can be polygonal, waist-shaped, broken line-shaped, etc.

[0099] In the above solution, during the production process of the battery cell 12 , the two first sub-positioning portions 12441 cooperate with the positioning tool 400 to further improve the positioning accuracy of the current collecting component 124 , which is beneficial to further improve the welding accuracy of the current collecting component 124 .

[0100] According to some embodiments of the present application, referring to Figures 4, 5 and 8, the current collecting component 124 also includes a second positioning portion 1245, which is arranged at the other end of the first connecting portion 1241 in the second direction Y, and the first direction X, the second direction Y and the thickness direction Z of the current collecting component are perpendicular to each other.

[0101] In the second direction Y, the first connection portion 1241 is provided with a first positioning portion 1244 and a second positioning portion 1245 at both ends, which means that after the current collecting component 124 is matched with the positioning tool 400 , the risk of shaking is relatively small.

[0102] The second positioning portion 1245 can be integrally formed with the first connecting portion 1241 or can be separately formed from the first connecting portion 1241 .

[0103] In the above scheme, the first positioning portion 1244 and the second positioning portion 1245 are respectively located at the two ends of the first connecting portion 1241 in the second direction Y. The first positioning portion 1244 and the second positioning portion 1245 cooperate with the positioning tool 400 to limit the tendency of the current collecting component 124 to rotate during welding, which is beneficial to further improve the welding accuracy of the current collecting component 124.

[0104] According to some embodiments of the present application, referring to Figures 4, 5, and 8, the first connecting portion 1241 includes a first edge 12411 and a second edge 12412 disposed opposite each other along a second direction Y. The second positioning portion 1245 extends from the second edge 12412 in a direction away from the first edge 12411. A notched corner 12451 is provided at one end of the second positioning portion 1245 away from the first connecting portion 1241.

[0105] In some embodiments, referring to FIG8 , a pair of current collecting members 124 are generally provided within the battery cell 12 . The two current collecting members 124 correspond to the positive electrode terminal and the negative electrode terminal, respectively. Since the positive and negative electrode terminals are generally made of different materials, the two current collecting members 124 are also designed to be made of different materials. The second positioning portion 1245 has a notched corner 12451 , which reduces the risk of incorrectly installing the current collecting member 124 when pre-installing it on the positioning fixture 400 . In other words, because the second positioning portion 1245 has a notched corner 12451 , only the current collecting member 124 corresponding to the positive electrode terminal can be pre-installed on the positioning fixture 400 corresponding to the positive electrode terminal.

[0106] In the above solution, during the cooperation between the current collecting member 124 and the positioning tool 400 , the provision of the notched corners 12451 can reduce the risk of the current collecting member 124 being pre-assembled in the wrong direction, thereby improving the production efficiency of the battery cells 12 .

[0107] According to some embodiments of the present application, referring to Figures 4 and 5 , the first connection portion 1241 has a first surface 12413 facing the electrode terminal 123. The current collecting member 124 includes two transition portions 1243, which are respectively provided at both ends of the first connection portion 1241 in the first direction X. The transition portions 1243 connect the first connection portion 1241 and the second connection portion 1242, and both the transition portions 1243 and the second connection portion 1242 protrude from the first surface 12413.

[0108] The transition portion 1243 connects the first connection portion 1241 and the second connection portion 1242. Both the transition portion 1243 and the second connection portion 1242 protrude from the first surface 12413. This means that within the battery cell 12, the first connection portion 1241 and the second connection portion 1242 are at different heights. This height difference inevitably creates an accommodation space, which can be used to accommodate the electrode tab 1221, thereby increasing the volume of the electrode assembly 122 within the battery cell 12. For example, as shown in FIG5 , the current collecting member 124 is in the shape of a cross, and the spaces at the lower left and right sides of the current collecting member 124 can be used to partially accommodate the electrode tab 1221.

[0109] In the above scheme, the second connecting portion 1242 and the transition portion 1243 both protrude from the first surface 12413, which means that in the thickness direction Z of the current collecting component, there is space for accommodating the electrode ear 1221 between the first connecting portion 1241 and the second connecting portion 1242, which is beneficial to increasing the volume share of the electrode assembly 122 in the battery cell 12, and further beneficial to increasing the volume energy density of the battery cell 12.

[0110] According to some embodiments of the present application, please refer to FIG. 2 . The present application provides a battery 100 , which includes the battery cell 12 in one or more embodiments of the first aspect.

[0111] In the above solution, since the battery cell 12 in the first aspect has a relatively long cycle life, the battery 100 including the battery cell 12 in one or more embodiments of the first aspect also has a relatively long cycle life.

[0112] According to some embodiments of the present application, please refer to Figure 1. The present application provides an electrical device, which includes the battery cell 12 in one or more embodiments of the first aspect, and the battery cell 12 is used to provide electrical energy; or, the electrical device includes the battery 100 in one or more embodiments of the second aspect, and the battery 100 is used to provide electrical energy.

[0113] According to some embodiments of the present application, with reference to FIG3-FIG5 and FIG8, the present application provides a battery cell 12, which includes a housing 121, an electrode terminal 123, an electrode assembly 122, and a current collecting member 124. The housing 121 includes an end cap 1211 and a shell 1212. The shell 1212 has an opening, and the end cap 1211 closes the opening. The electrode terminal 123 is disposed on the end cap 1211. The electrode assembly 122 is housed in the shell 1212 and includes a tab 1221.

[0114] The current collecting member 124 is disposed within the housing 1212. The current collecting member 124 is welded to the electrode terminal 123 to form a first weld mark 125, and the current collecting member 124 is welded to the tab 1221 to form a second weld mark 126. Along the thickness direction Z of the current collecting member, the projection of the first weld mark 125 onto the first plane 120 is a first projection 1250, and the projection of the second weld mark 126 onto the first plane 120 is a second projection 1260. The first plane 120 is perpendicular to the thickness direction Z of the current collecting member. The first projection 1250 and the second projection 1260 at least partially overlap along the first direction X, which is the thickness direction of the electrode assembly 122. The current collecting member 124 includes a first connection portion 1241 and two second connection portions 1242. The two second connection portions 1242 are arranged along the first direction X. The first connection portion 1241 is located between the two second connection portions 1242. The first connection portion 1241 is welded to the electrode terminal 123 to form a first weld mark 125. The second connection portion 1242 is welded to the tab 1221 to form a second weld mark 126. Along the first direction X, the two second weld marks 126 are arranged at intervals.

[0115] In the second direction Y, the size of the second connection portion 1242 is smaller than that of the first connection portion 1241 , and the first direction X, the second direction Y, and the thickness direction Z of the current collecting member are perpendicular to each other.

[0116] The current collecting member 124 also includes a first positioning portion 1244 and a second positioning portion 1245. The first positioning portion 1244 is disposed at one end of the first connecting portion 1241 in the second direction Y. The first connecting portion 1241 includes a first edge 12411 and a second edge 12412 oppositely disposed along the second direction Y. The first positioning portion 1244 includes two first sub-positioning portions 12441 spaced apart along the first direction X, each extending from the first edge 12411 away from the second edge 12412. The second positioning portion 1245 is disposed at the other end of the first connecting portion 1241 in the second direction Y. The first connecting portion 1241 includes a first edge 12411 and a second edge 12412 oppositely disposed along the second direction Y. The second positioning portion 1245 extends from the second edge 12412 away from the first edge 12411. A notch 12451 is provided at one end of the second positioning portion 1245 away from the first connecting portion 1241. The first direction X, the second direction Y and the thickness direction Z of the current collecting member are perpendicular to each other.

[0117] The first connection portion 1241 has a first surface 12413 facing the electrode terminal 123. The current collecting member 124 includes two transition portions 1243, which are respectively provided at both ends of the first connection portion 1241 in the first direction X. The transition portions 1243 connect the first connection portion 1241 and the second connection portion 1242. Both the transition portions 1243 and the second connection portion 1242 protrude from the first surface 12413. The current collecting member 124 is in the shape of a cross.

[0118] The at least partial overlap of the first projection 1250 and the second projection 1260 in the first direction X improves the cycle life of the battery cell 12. In the second direction Y, the second connection portion 1242 is smaller than the first connection portion 1241, enabling the current collecting member 124 to fuse promptly in the event of thermal runaway of the battery cell 12. The provision of the first positioning portion 1244, the second positioning portion 1245, and the notched corner 12451 facilitates improved production efficiency of the battery cell 12.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that, Comprising: A housing; Electrode terminals disposed on the wall of the housing; An electrode assembly received within the housing, the electrode assembly including tab ears; A current collecting member disposed within the housing, the current collecting member being welded to the electrode terminals to form a first weld mark and welded to the tab ears to form a second weld mark; Wherein, along the thickness direction of the current collecting member, the projection of the first weld mark on a first plane is a first projection, and the projection of the second weld mark on the first plane is a second projection, and the first plane is perpendicular to the thickness direction of the current collecting member; The first projection and the second projection at least partially overlap along a first direction, and the first direction is the thickness direction of the electrode assembly.

2. The battery cell according to claim 1, characterized in that There are two second weld marks, and along the first direction, the two second weld marks are spaced apart, and the first weld mark is located between the two second weld marks.

3. The battery cell according to claim 1 or 2, characterized in that, The current collecting member includes a first connecting portion and two second connecting portions, the two second connecting portions are arranged along the first direction, the first connecting portion is located between the two second connecting portions, the first connecting portion is welded to the electrode terminals to form the first weld mark, and the second connecting portion is welded to the tab ears to form the second weld mark.

4. The battery cell according to claim 3, characterized in that, In a second direction, the size of the second connecting portion is smaller than the size of the first connecting portion, and the first direction, the second direction and the thickness direction of the current collecting member are perpendicular to each other in pairs.

5. The battery cell according to claim 3 or 4, characterized in that, The current collecting member further includes a transition portion connecting the first connecting portion and the second connecting portion. In the second direction, the size of the transition portion is smaller than the size of the first connecting portion, and the size of the transition portion is smaller than the size of the second connecting portion. The first direction, the second direction and the thickness direction of the current collecting member are perpendicular to each other in pairs.

6. The battery cell according to any one of claims 3-5, characterized in that, The current collecting member further includes a first positioning portion provided at one end of the first connecting portion in the second direction, and the first direction, the second direction and the thickness direction of the current collecting member are perpendicular to each other in pairs.

7. The battery cell according to claim 6, characterized in that, The first connecting portion includes a first edge and a second edge oppositely disposed along the second direction. The first positioning portion includes two first sub-positioning portions, the two first sub-positioning portions are spaced apart along the first direction, and each first sub-positioning portion extends from the first edge in a direction away from the second edge.

8. The battery cell according to any one of claims 3-7, characterized in that, The current collecting member further includes a second positioning portion provided at the other end of the first connecting portion in the second direction, and the first direction, the second direction and the thickness direction of the current collecting member are perpendicular to each other in pairs.

9. The battery cell according to claim 8, wherein, The first connecting portion includes a first edge and a second edge oppositely disposed along the second direction. The second positioning portion extends from the second edge in a direction away from the first edge; A cutout is provided at one end of the second positioning portion away from the first connecting portion.

10. The battery cell according to any one of claims 3-9, characterized in that, The first connecting portion has a first surface facing the electrode terminals; The current collecting member includes two transition portions, the two transition portions are respectively disposed at two ends of the first connecting portion in the first direction, the transition portion connects the first connecting portion and the second connecting portion, and the transition portion and the second connecting portion both protrude from the first surface.

11. A battery, characterized in that, It includes a battery cell as described in any one of claims 1-10.

12. An electrical device, characterized in that, The electrical device includes a battery cell as described in any one of claims 1-10, and the battery cell is used to provide electrical energy; or, the electrical device includes a battery as described in claim 11, and the battery is used to provide electrical energy.

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