Battery cells, battery devices and electrical equipment

Abstract

The present application discloses a battery cell, a battery device and an electric device, wherein the battery cell comprises a housing, a motor assembly and a flexible connector, wherein the housing is provided with an electrode terminal; the electrode assembly is provided in the housing, and the electrode assembly comprises an electrode body and a tab; the flexible connector is electrically connected between the electrode terminal and the tab, and the flexible connector has a tab connection area, wherein at least part of the tab connection area comprises two stacked layer groups, and the tab is sandwiched and connected between the two layer groups. The battery device provided by the embodiment of the present application can improve reliability.

Description

Technical Field

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

[0002] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc.

[0003] The development of battery technology must take into account multiple design factors at the same time. For example, how to improve the reliability of battery cells is an important research direction in the battery field. Utility Model Content

[0004] The present application provides a battery cell, a battery device and an electrical equipment, which can improve reliability.

[0005] In the first aspect, the present application provides a battery cell, including a shell, an electrode assembly and a flexible connector, wherein the shell is provided with an electrode terminal; the electrode assembly is arranged in the shell, and the electrode assembly includes an electrode body and a pole ear; the flexible connector is electrically connected between the electrode terminal and the pole ear, and the flexible connector has a pole ear connection area, and the pole ear connection area includes two stacked layer groups, in the terminal connection area, the two layer groups are connected and fixed, and in the pole ear connection area, the pole ear is clamped and connected between the two layer groups.

[0006] In the technical solution of the embodiment of the present application, the battery cell includes a shell, an electrode assembly arranged in the shell, and a flexible connector for forming an electrical connection between the two, the flexible connector includes a pole ear connection area, in which two layer groups in the flexible connector are respectively connected to the opposite sides of the pole ear in the electrode assembly, thereby reducing the thickness of each layer group and making it easy to bend and not easy to crack. By setting a partial area of ​​the flexible connector to include a plurality of layer groups arranged at intervals from each other, the stress generated by bending can be reduced on the basis of maintaining a certain flow area, thereby reducing the possibility of cracking of the pole ear and the flexible connector, and improving the reliability of the battery cell.

[0007] According to some embodiments of the present application, the flexible connector further has a bending area and a terminal connection area, the tab connection area, the bending area and the terminal connection area are arranged in sequence along the extension direction of the flexible connector, and the terminal connection area is electrically connected to the electrode terminal, wherein: the thickness of the bending area is less than the thickness of the tab connection area and the thickness of the terminal connection area; or, the bending area is provided with a pre-bending groove recessed along the thickness direction of the flexible connector, the notch of the pre-bending groove is located on the side surface of one of the two layer groups away from the other, and the tab connection area is bent relative to the terminal connection area toward the side where the notch of the pre-bending groove is located; or, in the first direction, the size of the bending area is less than the size of the tab connection area and the size of the terminal connection area, and the first direction intersects with the extension direction of the flexible connector. The stress generated in the bending area after the bending is formed is reduced by thinning, pressing the pre-bending groove and setting the through-hole structure.

[0008] According to some embodiments of the present application, the bending zone is provided with a pre-bending groove, and in the extension direction of the flexible connector, the size of the pre-bending groove is 2mm-4mm, and the maximum depth of the pre-bending groove in the thickness direction of the flexible connector is 0.5mm-2mm. The pre-bending groove can reduce the bending stress and reduce the possibility of the pre-bending groove occupying too much space.

[0009] According to some embodiments of the present application, in the first direction, the size of the pre-bending groove is the same as the size of the bending zone, and the pre-bending groove is made to cross the flexible connector to make the bending stress more uniform.

[0010] According to some embodiments of the present application, in the first direction, the size of the bending area is smaller than the size of the tab connection area and the size of the terminal connection area; the bending area is provided with a through hole penetrating along the thickness direction of the flexible connector. The through hole is provided in the bending area to reduce the bending stress and facilitate processing.

[0011] According to some embodiments of the present application, the bending area is provided with a plurality of through holes, and the plurality of through holes are arranged in sequence along the first direction; and / or the through holes extend along the first direction. The through holes can be provided in a variety of different structural forms.

[0012] According to some embodiments of the present application, the through hole includes a first sub-hole extending along the first direction and two second sub-holes respectively arranged at opposite ends of the bending zone in the first direction; along the first direction, the size of the first sub-hole is 3mm-20mm, the size of the second sub-hole is 1mm-5mm, and along the extension direction of the flexible connector, the sizes of the first sub-hole and the second sub-hole are both 2mm-10mm. The possibility of too low strength of the bending zone is reduced on the basis of enabling the through hole to reduce the bending stress.

[0013] According to some embodiments of the present application, the terminal connection area includes two layer groups, the two layer groups are welded and connected to form a first welding area, the size of the first welding area is 10mm-100mm in the first direction, and the size of the first welding area is 10mm-60mm in the extension direction of the soft connector, and the first direction intersects with the extension direction of the soft connector. The connection between the layer groups is stable and easy to process.

[0014] According to some embodiments of the present application, the flexible connector is welded to the electrode terminal to form a second welding area, and along the thickness direction of the terminal connection area, the orthographic projection of the first welding area covers the orthographic projection of the second welding area, thereby reducing the possibility of relative deformation between the two layers of the flexible connector caused by the heat when the flexible connector is welded to the electrode terminal.

[0015] According to some embodiments of the present application, the layer group includes at least one sublayer, the sublayer includes a plurality of stacked main bodies and a bending portion connected between the main bodies, the bending portion is arranged at an edge of a side of the tab connection area away from the terminal connection area. The edges of each sublayer are arranged in a direction staggered from the tab to reduce the possibility of damaging the tab.

[0016] According to some embodiments of the present application, the layer group includes a plurality of sub-layers, and the plurality of sub-layers are stacked; and / or the layer group includes a plurality of sub-layers, and two main bodies of at least some of the sub-layers are sandwiched between two main bodies of adjacent sub-layers, so that the sub-layers can have different structures according to different stacking methods.

[0017] According to some embodiments of the present application, the thickness of the main body is 0.05 mm-0.1 mm, so that the sub-layer is easy to fold and has a certain structural strength.

[0018] According to some embodiments of the present application, in the terminal connection area, the main bodies of the two layer groups are welded and connected, and in the tab connection area, the main bodies of the layer groups are welded and connected respectively. The multiple sub-layers on the same side of the tab in the tab connection area are connected and fixed, so that they are not easily deformed and are easy to connect with the tab.

[0019] According to some embodiments of the present application, in the first direction, the size of the flexible connector is 10mm-100mm, the first direction intersects with the extension direction of the flexible connector, the thickness of the flexible connector is 0.2mm-1.2mm, and the thickness of the tab is 0.2mm-2mm, which reduces the possibility of the space required for the flexible connector being too large and the possibility of the structural strength being too low.

[0020] In a second aspect, the present application provides a battery device, including a box and a plurality of battery cells according to any one of the embodiments of the first aspect, wherein the battery cells are disposed in the box.

[0021] In a third aspect, the present application provides an electrical device, comprising the battery device in any embodiment of the second aspect, and the battery device is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0023] Figure 1 A simplified schematic diagram of a vehicle provided for some embodiments of the present application;

[0024] Figure 2 An exploded schematic diagram of a battery device provided in some embodiments of the present application;

[0025] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0026] Figure 4 A schematic diagram of the structure of a flexible connector provided in some embodiments of the present application;

[0027] Figure 5 A schematic diagram of the structure of a flexible connector provided in some other embodiments of the present application;

[0028] Figure 6 A schematic diagram of the structure of a flexible connector provided in some other embodiments of the present application;

[0029] Figure 7 A schematic diagram of the structure of a layer group provided in some embodiments of the present application;

[0030] Figure 8 A schematic diagram of the structure of layer groups provided for other embodiments of the present application.

[0031] Reference numerals:

[0032] 1000-Vehicles;

[0033] 100-battery cell; 200-battery device; 300-controller; 400-motor;

[0034] 10-shell; 20-electrode assembly; 30-soft connector; 40-box;

[0035] 11-electrode terminal; 21-electrode body; 22-ear; 31-ear connection area; 32-bending area; 33-terminal connection area; 34-layer group; 35-through hole; 36-second welding area; 41-first box body; 42-second box body; 43-accommodation part;

[0036] 331 - first welding area; 341 - sublayer; 342 - main body; 343 - bending portion; 351 - first subhole; 352 - second subhole;

[0037] X-extension direction of the soft connector; Y-first direction. DETAILED DESCRIPTION

[0038] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0040] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0041] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent 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.

[0042] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0043] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0044] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0045] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction 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 the specific circumstances.

[0046] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0047] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present application.

[0048] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through.

[0049] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0050] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0051] As an example, the positive electrode current collector may be a metal foil or a composite current collector.

[0052] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0053] As an example, the negative electrode current collector may be a metal foil, a foamed metal, or a composite current collector.

[0054] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0055] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0056] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc.

[0057] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0058] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0059] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0060] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0061] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0062] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. The electrolyte can be liquid, gel or solid.

[0063] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0064] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0065] In some embodiments, the housing may be provided with functional components such as electrode terminals, etc. The electrode terminals may be used to electrically connect to the electrode assembly to output or input electrical energy of the battery cell.

[0066] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no special limitation in this application.

[0067] The battery device mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0068] In some embodiments, the battery device may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0069] In some embodiments, the battery device may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0070] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0071] In some embodiments, the battery device may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0072] A battery cell is usually provided with a shell for providing containment and protection functions, as well as an electrode assembly and electrolyte for providing charge and discharge functions. The electrode assembly usually electrically connects the electrode tabs to the electrode terminals arranged in the shell through components such as adapters to serve as positive and negative electrodes.

[0073] On this basis, the applicant found that as the battery capacity increases, the thickness of its internal electrode assembly also increases. Accordingly, in order to gather the tabs at the two opposite ends in the thickness direction to the middle for connection, the required tab size also increases. In the process of processing the tabs and assembling the electrode assembly to the shell, the tabs that are too long are prone to cracking, resulting in reduced reliability of the battery cell. Especially for laminated batteries, the cracking of the tabs is prone to lithium precipitation, which seriously affects the overall quality of the battery cell.

[0074] In view of this, an embodiment of the present application provides a technical solution, which can reduce the possibility of tab cracking and improve the reliability of the battery cell by providing a soft connector between the electrode terminal on the shell and the tab of the electrode assembly.

[0075] The technical solutions described in the embodiments of the present application are applicable to battery devices and electrical equipment using battery devices, such as mobile phones, portable devices, laptop computers, electric vehicles, electric cars, ships, spacecraft, electric toys and electric tools, etc., wherein spacecrafts include airplanes, rockets, space shuttles and spacecrafts, etc., electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and electric tools include metal cutting power tools, grinding power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers.

[0076] The battery cells described in the embodiments of the present application are not limited to the electrical equipment described above, but for the sake of simplicity, the following embodiments are described using electric vehicles as examples.

[0077] See also Figure 1 , Figure 1 A simple schematic diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 200 may be provided inside the vehicle 1000, and specifically, for example, a battery device 200 may be provided at the bottom, front or rear of the vehicle 1000. The battery device 200 may be used to power the vehicle 1000, for example, the battery device 200 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 300 and a motor 400, and the controller 300 is used, for example, to control the battery to power the motor 400. The battery device 200 may be used for starting and navigating the vehicle 1000, and of course, the battery may also be used to drive the vehicle 1000, replacing or partially replacing fuel or natural gas to provide drive for the vehicle 1000.

[0078] Figure 2 Schematic diagram of an explosion of a battery device 200 provided in some embodiments of the present application. Figure 2 As shown, the battery device 200 includes a case 40 and a battery cell 100 , and the battery cell 100 is accommodated in the case 40 .

[0079] The box body 40 is used to accommodate the battery cell 100, and the box body 40 can be a variety of structures. In some embodiments, the box body 40 may include a first box body portion 41 and a second box body portion 42, the first box body portion 41 and the second box body portion 42 cover each other, and the first box body portion 41 and the second box body portion 42 jointly define a receiving portion 43 for accommodating the battery cell 100. The second box body portion 42 may be a hollow structure with one end open, the first box body portion 41 is a plate-like structure, and the first box body portion 41 covers the open side of the second box body portion 42 to form a box body 40 with a receiving portion 43; the first box body portion 41 and the second box body portion 42 may also be a hollow structure with one side open, and the open side of the first box body portion 41 covers the open side of the second box body portion 42 to form a box body 40 with a receiving portion 43. Of course, the first box body portion 41 and the second box body portion 42 may be a variety of shapes, such as a cylinder, a cuboid, etc.

[0080] In the battery, there can be one or more battery cells 100. If there are more than one battery cell 100, the battery cells 100 can be connected in series, in parallel, or in a mixed connection. A mixed connection means that the battery cells 100 are connected in series and in parallel. The battery cells 100 can be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the battery cells 100 can be accommodated in the box 40; of course, the battery cells 100 can also be connected in series, in parallel, or in a mixed connection to form a battery module, and then the battery modules can be connected in series, in parallel, or in a mixed connection to form a whole, and then accommodated in the box 40.

[0081] In some embodiments, there are multiple battery cells 100, and the multiple battery cells 100 are first connected in series, in parallel, or in hybrid connection to form a battery module. The multiple battery modules are then connected in series, in parallel, or in hybrid connection to form a whole, and are accommodated in the box body 40.

[0082] Next, combine with Figure 3 To Attachment Figure 8 The structures of battery cells, battery devices and electrical equipment are described.

[0083] Please also read Figures 3 to 6 , Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application, Figure 4 A schematic diagram of the structure of a soft connector provided in some embodiments of the present application, Figure 5 This is a schematic diagram of the structure of the soft connector provided in some other embodiments of the present application. Figure 6 A schematic diagram of the structure of a flexible connector provided in some other embodiments of the present application.

[0084] In the first aspect, the present application provides a battery cell 100, including a shell 10, an electrode assembly 20 and a flexible connector 30, the shell 10 is provided with an electrode terminal 11; the electrode assembly 20 is arranged in the shell 10, and the electrode assembly 20 includes an electrode body 21 and a pole ear 22; the flexible connector 30 is electrically connected between the electrode terminal 11 and the pole ear 22, the flexible connector 30 has a pole ear connection area 31, the pole ear connection area 31 includes two stacked layer groups 34, and the pole ear 22 is sandwiched and connected between the two layer groups 34.

[0085] The embodiment of the present application provides a battery cell 100, including a shell 10 for providing accommodation, support and protection, an electrode assembly 20 for providing electrical functions, and a soft connector 30 for achieving electrical connection between the two.

[0086] Specifically, the housing 10 may be enclosed to form a receiving cavity, and the electrode assembly 20 is disposed in the receiving cavity. The housing 10 may be provided with at least one electrode terminal 11, which is used to electrically connect the positive electrode and the negative electrode of the battery cell 100 with external components. The electrode assembly 20 may include an electrode body 21 and a pole ear 22 protruding from the edge of the electrode body 21. The electrode assembly 20 may be a winding type or a laminated type structure. The pole ear 22 may be formed by stacking a plurality of sheet-like pole sheets extending from different positions on the electrode body 21.

[0087] The flexible connector 30 is used to electrically connect the tab 22 of the electrode assembly 20 to the electrode terminal 11 on the housing 10. The flexible connector 30 has a tab connection area 31, and may further include a tab connection area 31, a bending area 32, and a terminal connection area 33 arranged in sequence along its own extension direction X. When the flexible connector 30 is disposed in the battery cell 100, the flexible connector 30 may be bent in the bending area 32 to allow a certain angle to exist between the tab connection area 31 and the terminal connection area 33.

[0088] Further, at least part of the tab connection area 31 may include two stacked layer groups 34, each layer group 34 may be a single-layer structure or a stack of multiple thinner structures, and the number of layers in the two layer groups 34 may be the same or different. The two layer groups 34 are connected and fixed to each other in the terminal connection area 33, and at the same time, they are at least partially independent of each other and spaced apart from each other in the tab connection area 31, and the tab 22 is sandwiched between the two layer groups 34. Optionally, the soft connector 30 may be set in the bending area 32 as a structure in which the two layer groups 34 are separated from each other, similar to the tab connection area 31, so as to further reduce the bending stress.

[0089] In the tab connection area 31 , the tab 22 may be clamped between two layer groups 34 and welded together, or the tab 22 may be divided into two groups and respectively connected to the sides of the two layer groups 34 close to each other.

[0090] In the technical solution of the embodiment of the present application, the battery cell 100 includes a shell 10, an electrode assembly 20 disposed in the shell 10, and a flexible connector 30 for forming an electrical connection between the two aforementioned, the flexible connector 30 includes a pole ear connection area 31, a bending area 32, and a terminal connection area 33. In the pole ear connection area 31, two layer groups 34 in the flexible connector 30 are respectively connected to the opposite sides of the pole ear 22 in the electrode assembly 20, thereby being able to reduce the thickness of each layer group 34 itself on the basis of maintaining sufficient flow area and making it easy to bend and not easy to crack. At the same time, the thinner flexible connector 30 can better adjust its own posture, which is convenient for setting with the pole ear 22, and can accordingly set the pole ear 22 in a posture with less bending stress, thereby further reducing the possibility of cracking of the pole ear 22 and the flexible connector 30, and improving the reliability of the battery cell 100.

[0091] In some optional embodiments, the soft connector 30 also has a bending zone 32 and a terminal connection zone 33, and the tab connection zone 31, the bending zone 32 and the terminal connection zone 33 are arranged in sequence along the extension direction X of the soft connector 30, and the terminal connection zone 33 is electrically connected to the electrode terminal 11, wherein: the thickness of the bending zone 32 is less than the thickness of the tab connection zone 31 and the thickness of the terminal connection zone 33; or, the bending zone 32 is provided with a pre-bending groove recessed along the thickness direction of the soft connector 30, and the notch of the pre-bending groove is located on the side surface of one of the two layer groups 34 away from the other, and the tab connection zone 31 is bent relative to the terminal connection zone 33 to the side where the notch of the pre-bending groove is located; or, in the first direction Y, the size of the bending zone 32 is smaller than the size of the tab connection zone 31 and the size of the terminal connection zone 33, and the first direction Y intersects with the extension direction X of the soft connector 30.

[0092] The two ends of the flexible connector 30 are electrically connected to the electrode terminal 11 and the electrode assembly 20, respectively. In the terminal connection area 33, the flexible connector 30 may be configured to first form a connection between two layer groups 34, and then the two layer groups 34 may be connected to the electrode terminal 11 by welding or the like. The connection between the layer groups 34 may be configured to be ultrasonic welding or the like, and the connection between the terminal connection area 33 and the electrode terminal 11 may be laser welding or the like.

[0093] Optionally, the flexible connector 30 may be provided with a weak portion in the bending area 32 to further reduce the bending stress in the area. Specifically, any one or more of the methods of reducing the thickness, providing a pre-bending groove, and providing a through hole 35 may be adopted.

[0094] Optionally, the thickness of the bending area 32 can be reduced by forging or the like, so that the thickness of the bending area 32 in the flexible connector 30 is less than the thickness of the terminal connection area 33 and the thickness of the tab connection area 31, wherein the thickness of the terminal connection area 33 can be selected to be the same as the thickness of the tab connection area 31, and the thickness of each part in the thinned area can be selected to be the same. In this embodiment, the area with reduced thickness can be selected to extend along the first direction Y and traverse the flexible connector 30 to reduce the possibility of stress concentration in the unthinned area on the bending line. The first direction Y intersects with the arrangement direction of the terminal connection area 33, the bending area 32, and the tab connection area 31, and can be selected to be perpendicular to each other.

[0095] Alternatively, the flexible connector 30 can also reduce the bending stress by providing a pre-bending groove. Specifically, since the flexible connector 30 includes two layer groups 34 and each layer group 34 can be selected to include a plurality of layer structures, when bending, there is a possibility of generating a large stress due to the different bending radii of the inner and outer layers. Therefore, it can be selected to first press and form a pre-bending groove at the position to be bent before bending the flexible connector 30, and the pre-bending groove is set in the direction where the terminal connection area 33 is bent close to the tab connection area 31, that is, the terminal connection area 33 and the tab connection area 31 are bent toward the side where the notch of the pre-bending groove is located.

[0096] Optionally, in the embodiment provided with a pre-bending groove, the pre-bending groove may be selected to have a recessed depth less than the thickness of the soft connector 30, and the whole is located within the thickness range of the soft connector 30. Alternatively, one side surface of the bending zone 32 may be recessed inwardly, while the other side surface opposite to the pre-bending groove may be convex outwardly, and the depth of the pre-bending groove may be greater than or equal to the thickness of the soft connector 30.

[0097] Alternatively, the bending zone 32 may have an extension dimension in the first direction Y that is smaller than the terminal connection zone 33 and the tab connection zone 31. Optionally, the extension dimension of the terminal connection zone 33 in this direction may be the same as the extension dimension of the tab connection zone 31 in this direction, and this dimension may be selected to match the dimension of the tab 22.

[0098] It can be understood that the extension dimension of the bending zone 32 in the first direction Y here refers to the sum of the dimensions of the flexible connector 30 passing through a straight line drawn in the bending zone 32 along the first direction Y. Exemplarily, the bending zone 32 can be optionally reduced in dimension in the first direction Y by providing a through hole 35, and the dimension of the bending zone 32 in the first direction Y is the difference between the dimension of the flexible connector 30 in the direction and the extension dimension of the through hole 35 in the direction.

[0099] Optionally, when the through holes 35 are provided, the through holes 35 may be symmetrically provided in the first direction Y, so that the flexible connector 30 is subjected to uniform force after being bent.

[0100] By reducing the thickness, pressing the pre-bending groove and providing the through hole 35 , a weak area can be formed at the bending zone 32 . Bending at the weak area can reduce the stress generated in the bending zone 32 after bending deformation.

[0101] In some optional embodiments, the bending zone 32 is provided with a pre-bending groove, and in the extension direction X of the flexible connector 30, the size of the pre-bending groove is 2mm-4mm, and the maximum depth of the pre-bending groove in the thickness direction of the flexible connector 30 is 0.5mm-2mm.

[0102] In the embodiment where the bending zone 32 is provided with a pre-bending groove, the size of the pre-bending groove in the extension direction X of the flexible connector 30, that is, the width of the pre-bending groove can be 2mm-4mm, for example, it can be any one of 2mm, 2.5mm, 3mm, 3.5mm, 4mm or between any two thereof. At the same time, along the self-concave direction, that is, the thickness direction of the flexible connector 30, the maximum depth of the flexible connector groove can be 0.5mm-2mm, for example, it can be any one of 0.5mm, 1mm, 1.5mm, 2mm or between any two thereof.

[0103] For example, when the width of the pre-bending groove is 2 mm, the required width of the pre-bending groove is small, thereby reducing the required width of the bending area; when the width of the pre-bending groove is 4 mm, the ability of the pre-bending groove to reduce bending stress is large, which can further reduce the possibility of damage or rupture of the flexible connector 30 and the tab 22. Similarly, when the depth of the pre-bending groove is 0.5 mm, the size of the pre-bending groove protruding from the adjacent area after bending can be reduced, and the space required for the flexible connector 30 as a whole can be reduced. When the depth of the pre-bending groove is 2 mm, the effect of reducing bending stress can be improved, and the possibility of damage or rupture of the flexible connector 30 and the tab 22 can be further reduced.

[0104] It can be understood that the maximum depth of the pre-bent groove here refers to the maximum distance between the bottom wall and the notch of the pre-bent groove in the thickness direction of the flexible connector 30 after the flexible connector 30 is flattened.

[0105] By setting the width and depth of the pre-bending groove within the aforementioned range, the pre-bending groove can have the function of reducing bending stress, while reducing the possibility of the pre-bending groove occupying too much space and the bending radius being too large, which may lead to squeezing of the pole ear 22.

[0106] In some optional embodiments, in the first direction Y, the size of the pre-bending groove is the same as the size of the bending zone 32.

[0107] Optionally, when setting the pre-bending groove, its size in its own extension direction can be the same as the size of the flexible connector 30 in the first direction Y, that is, the pre-bending groove can be made to cross the flexible connector 30 to form a uniform weak area in the first direction Y, so that the bending part of the flexible connector 30 is subjected to uniform force, thereby reducing the possibility of stress concentration at the place where the pre-bending groove is not set.

[0108] In some optional embodiments, in the first direction Y, the size of the bending zone 32 is smaller than the size of the tab connection zone 31 and the size of the terminal connection zone 33 ; the bending zone 32 is provided with a through hole 35 penetrating along the thickness direction of the flexible connector 30 .

[0109] In an embodiment of reducing the size of the bending zone 32 along the first direction Y, the specific method adopted is to set at least one through hole 35 penetrating along the thickness direction in the bending zone 32. The through hole 35 can be a round hole, a square hole, a waist-shaped hole, a polygonal hole, etc., and its extension size in the first direction Y is set according to the required strength of the bending zone 32.

[0110] By providing a through hole in the bending zone 32 to reduce the size of the bending zone 32 in the first direction Y, and thus reducing the bending stress, the flexible connector 30 can be easily processed.

[0111] In some optional embodiments, the bending area 32 is provided with a plurality of through holes 35 , and the plurality of through holes 35 are arranged in sequence along the first direction Y; and / or the through holes 35 extend along the first direction Y.

[0112] In the embodiment where the bending zone 32 is provided with a plurality of through holes 35, these through holes 35 may be optionally extended along the first direction Y, and / or, these through holes 35 may be arranged in sequence along the first direction Y. Exemplarily, the plurality of through holes 35 may have the same or similar structure and size, and may be arranged at equal intervals in the first direction Y. Alternatively, each through hole 35 may have a certain extension dimension in the first direction Y, so that its dimension in the first direction Y is greater than its dimension in the extension direction X of the flexible connector 30, and its specific extension dimension in the first direction Y may be set according to the total dimension required for the bending zone 32.

[0113] In order to reduce the size of the bending area 32 in the first direction Y, the through hole 35 therein can be set to a variety of different structural forms, so that it is easy to process and can adapt to battery cells 100 of different sizes.

[0114] In some optional embodiments, the through hole 35 includes a first sub-hole 351 extending along the first direction Y and two second sub-holes 352 respectively arranged at the opposite side ends of the bending zone 32 in the first direction Y; along the first direction Y, the size of the first sub-hole 351 is 3mm-20mm, and the size of the second sub-hole 352 is 1mm-5mm, and along the extension direction X of the soft connector 30, the sizes of the first sub-hole 351 and the second sub-hole 352 are both 2mm-10mm.

[0115] For example, the bending area 32 may be provided with a plurality of through holes 35, and the through holes 35 include a first sub-hole 351 located in the middle in the first direction Y and a second sub-hole 352 located at the edges of opposite sides in the direction, wherein the first sub-hole 351 may have a larger extension dimension in the direction. At the same time, in order to reduce the possibility of stress concentration at the edge of the through hole 35, the first sub-hole 351 and the second sub-hole 352 may be selected to have a relatively smooth contour shape, wherein the first sub-hole 351 may be selected to be a waist-shaped hole, and the second sub-hole 352 may be selected to be a semicircular or semi-elliptical hole.

[0116] On this basis, in the first direction Y, the size of the first sub-hole 351 can be 3mm-20mm, for example, it can be any one of 3mm, 6mm, 9mm, 12mm, 15mm, 18mm, 20mm or between any two thereof, and the size of the second sub-hole 352 is 1mm-5mm, for example, it can be any one of 1mm, 2mm, 3mm, 4mm, 5mm or between any two thereof. In the arrangement direction of the soft connector 30, the sizes of the first sub-hole 351 and the second sub-hole 352 can be the same or similar, and both can be selected from 2mm-10mm, for example, it can be any one of 2mm, 4mm, 6mm, 8mm, 10mm or between any two thereof.

[0117] By limiting the structural form and size of the through hole 35 , it is possible to reduce the possibility of the bending zone 32 being too small in size and too low in strength in the first direction Y, thereby reducing the possibility of easy breakage, while enabling the through hole 35 to provide the function of reducing bending stress.

[0118] In some optional embodiments, the terminal connection area 33 includes two layer groups 34, which are welded to form a first welding area 331. In the first direction Y, the size of the first welding area 331 is 10mm-100mm, and in the extension direction X of the soft connector 30, the size of the first welding area 331 is 10mm-60mm. The first direction Y intersects with the extension direction X of the soft connector 30.

[0119] Optionally, the flexible connector 30 can be made entirely of two layer groups 34 , which are fixedly connected or integrally arranged in the terminal connection area 33 , independently arranged in the tab connection area 31 , and can be connected or independently arranged in the bending area 32 .

[0120] On this basis, the terminal connection area 33 in the soft connector 30 is used to electrically connect to the electrode terminal 11. In this area, the two layer groups 34 can be fixedly connected and arranged, and can be connected by welding to form a first welding area 331 with a certain size. The first welding area 331 is located in the terminal connection area 33, and can be arranged near the middle of the terminal connection area 33 and spaced from each edge.

[0121] Optionally, the size of the first welding area 331 in the first direction Y can be 10mm-100mm, for example, any one of 10mm, 30mm, 50mm, 70mm, 90mm, 100mm or between any two thereof. At the same time, in the extension direction X of the soft connector 30, that is, the arrangement direction of the three regions, the size of the first welding area 331 can be 10mm-60mm, for example, any one of 10mm, 20mm, 30mm, 40mm, 50mm, 60mm or between any two thereof. The specific size of the first welding area 331 can be set according to parameters such as the size of the entire soft connector 30, the size of the terminal connection area 33, and the thickness of the layer group 34.

[0122] By adopting welding connection between two layer groups 34 and limiting the size of the welding area, the connection can be made stable and reliable and easy to process.

[0123] In some optional embodiments, the flexible connector 30 is welded to the electrode terminal 11 to form a second welding area 36 , and along the thickness direction of the terminal connection area 33 , the orthographic projection of the first welding area 331 covers the orthographic projection of the second welding area 36 .

[0124] In an embodiment in which two layer groups 34 in the terminal connection area 33 are welded together to form a first welding area 331, the soft connector 30 and the electrode terminal 11 can be welded together to form a second welding area 36, ​​which can be optionally smaller in size than the first welding area 331, and can be located within the first welding area 331.

[0125] On this basis, when the soft connector 30 is welded to the electrode terminal 11, the partial area where the two layer groups 34 are connected can be welded to the electrode terminal 11, thereby reducing the possibility of defects in the connection with the electrode terminal 11 caused by gaps between the layer groups 34, and at the same time reducing the possibility of the soft connector 30 being deformed due to heat when connected to the electrode terminal 11 and encroaching on the space of the tab 22.

[0126] Please also read Figure 7 and Box Figure 8 , Figure 7 A schematic diagram of the structure of a layer group provided in some embodiments of the present application, Figure 8 A schematic diagram of the structure of layer groups provided for other embodiments of the present application.

[0127] In some optional embodiments, the layer group 34 includes at least one sublayer 341, the sublayer 341 includes a plurality of stacked main bodies 342 and a bending portion 343 connected between the main bodies 342, and the bending portion 343 is arranged on a side edge of the tab connection area 31 away from the terminal connection area 33.

[0128] The flexible connector 30 includes two stacked layer groups 34, and optionally, each layer group 34 may include a plurality of sub-layers 341, and these sub-layers 341 are at least partially stacked with each other to form the layer group 34. Each sub-layer 341 may include a main body 342 that is relatively arranged and extends in parallel in the thickness direction of the layer group 34 and a bending portion 343 connected between the main bodies 342, and each sub-layer 341 may be formed by folding a single layer structure.

[0129] For example, when processing the flexible connector 30, a single-layer substrate may be processed by winding or folding multiple times to form a multi-layer stacked structure, and then the structure may be cut to obtain the layer group 34. When cutting, the edges other than the edge of the side of the tab connection area 31 facing the electrode body 21 may be cut, so that the side edge of the tab connection area 31 facing the electrode body 21, that is, the side edge extending from the tab 22, retains the bent connection structure formed by the side folding / winding.

[0130] By arranging the bent portions 343 at the edge of the tab connection area 31 away from the terminal connection area 33 , the possibility of the edge of the main body 342 contacting the tab 22 and causing the tab 22 to be cut can be reduced, thereby improving the possibility of the battery cell 100.

[0131] In some optional embodiments, the layer group 34 includes multiple sub-layers 341, and the multiple sub-layers 341 are stacked; and / or the layer group 34 includes multiple sub-layers 341, and the two main bodies 342 of at least some of the sub-layers 341 are sandwiched between the two main bodies 342 of adjacent sub-layers 341.

[0132] In the embodiment where the layer group 34 includes a plurality of sub-layers 341, each sub-layer 341 may have different structural forms according to the formation method of the layer group 34. For example, in the embodiment where the layer group 34 is made by folding the substrate multiple times, each sub-layer 341 may be stacked accordingly, that is, the two main bodies 342 of each sub-layer 341 are stacked, and except for the two sub-layers 341 at the top and the bottom, the surfaces of the two main bodies 342 of other sub-layers 341 facing away from each other are respectively against the main body 342 of the adjacent sub-layer 341.

[0133] Alternatively, in an embodiment in which the layer group 34 is prepared by winding a substrate, each sublayer 341 can be arranged in sequence around the adjacent inner sublayer 341, that is, the two main bodies 342 in the innermost sublayer 341 are stacked, and each other sublayer 341 correspondingly surrounds the adjacent inner sublayer 341, and the side surface of the main body 342 of each sublayer 341 facing away from each other is respectively abutted against the two main bodies 342 of the same adjacent sublayer 341.

[0134] According to the processing method of the layer group 34 , the plurality of sub-layers 341 may have different structures, so that the sub-layers 341 are easy to process and have good applicability.

[0135] In some optional embodiments, the thickness of the main body 342 is 0.05 mm-0.1 mm.

[0136] Optionally, each sublayer 341 in the flexible connector 30 may have the same or similar thickness, and each sublayer 341 may have uniform thickness in its own regions, so that each sublayer 341 has a sheet-like structure with uniform thickness before folding.

[0137] Specifically, the thickness of each sub-layer 341 in the main body 342 may be selected to be 0.05 mm-0.1 mm, for example, it may be any one of 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm or between any two thereof.

[0138] By making the thickness of each sub-layer 341 within the aforementioned range, the sub-layer 341 can be easily folded or rolled up to form a preset shape, while at the same time the sub-layer 341 can have a certain structural strength and be not easily broken.

[0139] In some optional embodiments, in the terminal connection area 33 , the main bodies 342 in the two layer groups 34 are welded together, and in the tab connection area 31 , the main bodies 342 in the layer groups 34 are welded together.

[0140] In the battery cell 100, the pole tab 22 of the electrode assembly 20 is sandwiched between two layer groups 34 of the flexible connector 30. In an embodiment where each layer group 34 is composed of multiple sublayers 341, multiple main bodies 342 in the same layer group 34 can be optionally first welded and connected in the terminal connection area 33 to connect and fix the multiple sublayers 341 in the same layer group 34, and then the two layer groups 34 are connected and fixed to the pole tab 22.

[0141] Optionally, the sub-layers 341 of the same layer group 34 can be welded together by ultrasonic welding or the like, and the welding areas in the two sub-layers 341 on both sides of the pole lug 22 can be corresponding to each other in the thickness direction of the flexible connector 30. When the layer group 34 and the pole lug 22 are welded together, the welding area between the layer group 34 and the pole lug 22 can be located within the contour range of the welding area between the sub-layers 341 in the layer group 34 to reduce the possibility of misalignment caused by different degrees of deformation between the sub-layers 341 that are not connected to each other.

[0142] By connecting and fixing the plurality of sub-layers 341 located on the same side of the pole lug 22 in the pole lug connection area 31 , it is possible to prevent the sub-layers 341 from being dislocated or deformed and facilitate connection with the pole lug 22 .

[0143] In some optional embodiments, in the first direction Y, the size of the soft connector 30 is 10 mm-100 mm, the first direction Y intersects with the extension direction X of the soft connector 30, the thickness of the soft connector 30 is 0.2 mm-1.2 mm, and the thickness of the tab 22 is 0.2 mm-2 mm.

[0144] The flexible connector 30 is used to form an electrical connection between the electrode terminal 11 and the electrode assembly 20. Optionally, the width of the flexible connector 30, that is, its size in the first direction Y, can match the size of the tab 22 in the direction, and specifically can be made the same or slightly larger than the size of the flexible connector 30. In this direction, the size of the flexible connector 30 can be selected from 10 mm to 100 mm, for example, any one of 10 mm, 30 mm, 50 mm, 70 mm, 90 mm, and 100 mm, or between any two of them.

[0145] The thickness of the flexible connector 30 can be designed according to the required flow area and structural strength, and can be specifically 0.2 mm-1.2 mm, for example, any one of 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, or any two thereof. Correspondingly, the thickness of the tab 22 can be 0.2 mm-2 mm, for example, any one of 0.2 mm, 0.6 mm, 1 mm, 1.4 mm, 1.8 mm, 2 mm, or any two thereof.

[0146] By limiting the width and thickness of the flexible connector 30 and the tab 22 , the two can be adapted to each other, while reducing the possibility that the space required by the flexible connector 30 is too large and the possibility that the structural strength of the flexible connector 30 is too low and easy to break.

[0147] Example

[0148] The following examples more specifically describe the contents disclosed in the examples of the present application. These examples are only used for illustrative descriptions, because various modifications and changes within the scope of the contents disclosed in the examples of the present application are obvious to those skilled in the art.

[0149] 1. Preparation of positive electrode

[0150] The positive electrode sheet includes a positive electrode collector and a positive electrode film layer. The positive electrode film layer is located on both sides of the positive electrode collector. The positive electrode collector is an aluminum foil. The positive electrode film layer is formed by evenly coating the positive electrode slurry (the solvent is N-methylpyrrolidone NMP) on the surface of the positive electrode collector aluminum foil, drying, and cold pressing. The positive electrode film layer includes a positive electrode active material, a conductive agent carbon black (Super P), and a binder polyvinylidene fluoride (PVDF) in a weight ratio of 97:1:2.

[0151] The positive electrode active material includes a LiNi 0.8 Co 0.1 Mn 0.1 Layered transition metal oxides of O2 (NCM811).

[0152] 2. Preparation of negative electrode sheet

[0153] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer. The negative electrode film layer is located on both sides of the negative electrode current collector. The negative electrode current collector is copper foil. The negative electrode film layer is formed by evenly coating the negative electrode slurry (the solvent is deionized water) on the surface of the negative electrode current collector copper foil, drying, and cold pressing. The negative electrode film layer includes silicon-based materials (specifically silicon oxides), graphite, conductive agent carbon black, conductive agent carbon nanotubes, and binder polyacrylic acid in a weight ratio of 12.6:82.4:1.9:0.1:3.

[0154] 3. Preparation of Isolators

[0155] Provide PE (Polyethylene) based film.

[0156] 4. Preparation of electrolyte

[0157] The electrolyte includes an organic solvent and a lithium salt. Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, sufficiently dried lithium salt LiPF6 is dissolved in the mixed organic solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0158] 5. Installation and testing of battery cells 100

[0159] The positive electrode sheet, separator and negative electrode sheet are stacked in order so that the separator is between the positive electrode sheet and the negative electrode sheet to play an isolating role, and the positive electrode sheet, separator and negative electrode sheet are wound or stacked to obtain an electrode assembly 20; a flexible connector 30 is provided, and the size parameters of the flexible connector 30 are measured, and the pole ear connection area 31 and the terminal connection area 33 of the flexible connector 30 are respectively welded to the pole ear 22 in the electrode assembly 20 and the electrode terminal 11 on the shell 10, and the pole ear 22 and the flexible connector 30 are bent and assembled into the shell 10; the damage inside the battery cell 100 is detected after the pole ear 22 and the flexible connector 30 are bent.

[0160] Among them, the flexible connector 30 includes a first welding area 331, each layer group 34 includes a plurality of sub-layers 341, and the bending area 32 is provided with a through hole 35, the through hole 35 includes a first sub-hole 351 and a second sub-hole 352, the first sub-hole 351 is a waist-shaped hole with a rectangular middle part and semicircular ends, and the second sub-hole 352 is a semicircular hole.

[0161] On this basis, the size of the first welding area 331 in the extension direction X of the flexible connector 30 is recorded as L1, the size of the first welding area 331 in the first direction Y is recorded as L2, the thickness of each sublayer 341 is recorded as H, the radius of the second sub-hole 352 is recorded as R, the size of the rectangular part of the first sub-hole 351 in the first direction Y is recorded as L3, and the size of the flexible connector 30 in the first direction Y is recorded as L4. The test results of each embodiment are shown in Table 1 below:

[0162]

[0163] According to the above results, embodiments 1 to 3 all achieve good results. By providing the flexible connector 30 and making it within a certain size range, the reliability of the battery cell 100 after the tab 22 is bent can be improved.

[0164] In a second aspect, the present application provides a battery device 200 , including a box body and a plurality of battery cells 100 in any embodiment of the first aspect, wherein the battery cells 100 are disposed in the box body 40 .

[0165] In a third aspect, the present application provides an electrical device, comprising the battery device 200 in any embodiment of the second aspect, and the battery device 200 is used to provide electrical energy.

[0166] The battery device 200 and the electrical equipment in the embodiment of the present application have all the beneficial effects of the battery cell 100 in the first aspect. For details, please refer to the specific description of the battery cell 100 in the above embodiments, which will not be repeated in this embodiment.

[0167] The embodiment of the present application provides a battery cell 100, including a shell 10, an electrode assembly 20 and a flexible connector 30, wherein the shell 10 is provided with an electrode terminal 11; the electrode assembly 20 is arranged in the shell 10, and the electrode assembly 20 includes an electrode body 21 and a pole ear 22; the flexible connector 30 is electrically connected between the electrode terminal 11 and the pole ear 22, and the flexible connector 30 includes a pole ear connection area 31, a bending area 32 and a terminal connection area 33 arranged in sequence along its own extension direction X, and the flexible connector 30 includes two layer groups 34 stacked, and in the terminal connection area 33, the two layer groups 34 are connected and fixed, and in the pole ear connection area 31, the pole ear 22 is sandwiched and connected between the two layer groups 34.

[0168] In the first direction Y, the size of the bending area 32 is smaller than the size of the tab connection area 31 and the size of the terminal connection area 33, and the first direction Y intersects with the extension direction X of the flexible connector 30. The bending area 32 is provided with a plurality of through holes 35, and the plurality of through holes 35 are arranged in sequence along the first direction Y; and / or the through holes 35 extend along the first direction Y. The layer group 34 includes at least one sublayer 341, and the sublayer 341 includes a plurality of main body portions 342 stacked and a bending portion 343 connected between the main body portions 342, and the bending portion 343 is provided at a side edge of the tab connection area 31 away from the terminal connection area 33.

[0169] 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 replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should 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: include: A housing provided with electrode terminals; An electrode assembly is disposed in the housing, and the electrode assembly includes an electrode body and an electrode tab; A flexible connector is electrically connected between the electrode terminal and the tab. The flexible connector has a tab connection area. At least part of the tab connection area includes two stacked layer groups. The tab is sandwiched and connected between the two layer groups.

2. The battery cell according to claim 1, characterized in that: The flexible connector further comprises a bending area and a terminal connection area, wherein the tab connection area, the bending area and the terminal connection area are sequentially arranged along the extension direction of the flexible connector, and the terminal connection area is electrically connected to the electrode terminal, wherein: The thickness of the bending area is smaller than the thickness of the tab connection area and the thickness of the terminal connection area; Alternatively, the bending area is provided with a pre-bending groove recessed along the thickness direction of the flexible connector, the notch of the pre-bending groove is located on a side surface of one of the two layer groups away from the other, and the tab connection area is bent relative to the terminal connection area toward the side where the notch of the pre-bending groove is located; Alternatively, in a first direction, the size of the bending area is smaller than the size of the tab connection area and the size of the terminal connection area, and the first direction intersects with the extension direction of the flexible connector.

3. The battery cell according to claim 2, characterized in that: The bending zone is provided with a pre-bending groove. In the extension direction of the flexible connector, the size of the pre-bending groove is 2mm-4mm, and the maximum depth of the pre-bending groove in the thickness direction of the flexible connector is 0.5mm-2mm.

4. The battery cell according to claim 3, characterized in that: In the first direction, the size of the pre-bending groove is the same as the size of the bending zone.

5. The battery cell according to claim 2, characterized in that: In the first direction, the size of the bending area is smaller than the size of the tab connection area and the size of the terminal connection area; The bending area is provided with a through hole penetrating along the thickness direction of the flexible connector.

6. The battery cell according to claim 5, characterized in that: The bending area is provided with a plurality of the through holes, and the plurality of the through holes are arranged in sequence along the first direction; And / or, the through hole extends along the first direction.

7. The battery cell according to claim 6, characterized in that: The through hole comprises a first sub-hole extending along the first direction and two second sub-holes respectively arranged at opposite side ends of the bending area in the first direction; Along the first direction, the size of the first sub-hole is 3mm-20mm, the size of the second sub-hole is 1mm-5mm, and along the extension direction of the flexible connector, the sizes of the first sub-hole and the second sub-hole are both 2mm-10mm.

8. The battery cell according to claim 2, characterized in that: The terminal connection area includes two layer groups, which are welded together to form a first welding area. In the first direction, the size of the first welding area is 10mm-100mm, and in the extension direction of the soft connector, the size of the first welding area is 10mm-60mm. The first direction intersects with the extension direction of the soft connector.

9. The battery cell according to claim 8, characterized in that: The flexible connector is welded to the electrode terminal to form a second welding area. Along the thickness direction of the terminal connection area, the orthographic projection of the first welding area covers the orthographic projection of the second welding area.

10. The battery cell according to claim 2, characterized in that: The layer group includes at least one sublayer, and the sublayer includes a plurality of main body parts stacked and a bending part connected between the main body parts, and the bending part is arranged at an edge of one side of the tab connection area away from the terminal connection area.

11. The battery cell according to claim 10, characterized in that: The layer group includes a plurality of the sub-layers, and the plurality of the sub-layers are stacked; And / or, the layer group includes a plurality of the sub-layers, and the two main body portions of at least some of the sub-layers are sandwiched between two main body portions of adjacent sub-layers.

12. The battery cell according to claim 10, characterized in that: The thickness of the main body is 0.05mm-0.1mm.

13. The battery cell according to claim 10, characterized in that: In the terminal connection area, the main bodies in the two layer groups are welded and connected, and in the tab connection area, the main bodies in the layer groups are welded and connected respectively.

14. The battery cell according to claim 1, characterized in that: In the first direction, the size of the flexible connector is 10 mm-100 mm, the first direction intersects with the extension direction of the flexible connector, the thickness of the flexible connector is 0.2 mm-1.2 mm, and the thickness of the tab is 0.2 mm-2 mm.

15. A battery device, characterized in that: include: Box; A plurality of battery cells according to any one of claims 1 to 14, wherein the battery cells are arranged in the box.

16. An electrical equipment, characterized in that: Comprising the battery device as claimed in claim 15, the battery device is used to provide electrical energy.

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