Battery cell, method and device for manufacturing the same, and electrical device

Abstract

An embodiment of the present application provides a battery cell, a manufacturing method and device thereof, and an electrical device. The battery cell includes: a housing (101) having an opening (1011); an end cover assembly (102) for closing the opening (1011), the end cover assembly (102) including an end cover body (1021) and an electrode terminal (1022), the electrode terminal (1022) being insulatingly connected to the end cover body (1021); and an electrode assembly (10) disposed within the housing (101), the electrode assembly (10) being in a wound structure and including: a main body portion (11), a first tab group (12), and a second tab group (13), the first tab group (12) and the second tab group (13) having opposite polarities and being connected to the same side of the main body portion (11) along the winding axis (K); the first tab group (12) being electrically connected to the electrode terminal (1022), and the center line of the electrode terminal (1022) being offset by a preset distance in the radial direction of the winding structure with respect to the winding axis (K), and the second tab group (13) being electrically connected to the end cover body (1021).

Description

Technical Field

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

[0002] Due to the advantages of high energy density, high power density, many cycle usage times, long storage time, etc. of lithium-ion and other batteries, they have been widely used in electric vehicles.

[0003] However, improving the working performance of batteries in electric vehicles has always been a difficult problem in the industry. Summary of the Invention

[0004] The purpose of the present application is to improve the performance of the battery.

[0005] According to the first aspect of the present application, a battery cell is provided, including:

[0006] A housing having an opening;

[0007] An end cap assembly for closing the opening, the end cap assembly includes an end cap body and an electrode terminal, and the electrode terminal is insulated and connected to the end cap body; and

[0008] An electrode assembly disposed in the housing, the electrode assembly has a wound structure and includes: a main body portion, a first tab group and a second tab group, the first tab group and the second tab group have opposite polarities, and are connected to the same side of the main body portion along the winding axis of the wound structure;

[0009] Wherein, the first tab group is electrically connected to the electrode terminal, and the center line of the electrode terminal is offset by a preset distance in the radial direction of the wound structure with respect to the winding axis, and the second tab group is electrically connected to the end cap body.

[0010] In this embodiment, the first tab group and the second tab group are led out from the same end of the main body portion, only the electrical connection space needs to be reserved at one end of the electrode assembly, and it is also unnecessary to provide electrode terminals at both ends of the battery cell respectively, which can effectively improve the overall energy density of the battery cell. When the capacity of the battery cell is certain, the volume of the battery cell can be reduced, making it easier to layout the battery in the electrical device.

[0011] Moreover, only one electrode terminal is provided for the battery cell. The first tab group is electrically connected to the electrode terminal, and the second tab group is directly electrically connected to the end cap body, which can simplify the structure and assembly process of the battery cell. By omitting one electrode terminal, a larger space can be left on the end cap body. The center line of the electrode terminal is offset by a preset distance in the radial direction of the winding structure relative to the winding axis, which can further increase the space on the end cap body on the side of the electrode terminal. On the one hand, it is easy to layout the liquid injection hole and pressure relief structure on the end cap body, and also leaves sufficient space for arranging the temperature acquisition component, the bus bar between battery cells, and various wires. On the other hand, the position of the electrode terminal can be flexibly adjusted according to the position of the first tab group, which is also beneficial to increasing the cross-sectional area of the electrode terminal to increase the overcurrent capacity of the battery cell.

[0012] In some embodiments, the first tab group and the second tab group are arranged at intervals along the circumferential direction of the winding structure.

[0013] In this embodiment, the first tab group is entirely located on one side of the winding axis. When electrically connecting the first tab group to the electrode terminal, the center line of the electrode terminal can be offset in the radial direction of the winding structure relative to the winding axis. Moreover, such a structure can separate the first tab group and the second tab group in space to avoid short circuit, and may also allow the electrolyte to infiltrate into the main body through the interval area, so that during the charge and discharge process of the battery cell, the electrolyte can fully react with the active substances on the first electrode and the second electrode.

[0014] In some embodiments, a first groove is provided on the surface of the electrode terminal away from the electrode assembly. The first groove is recessed towards the direction close to the electrode assembly. A first welding part is formed between the bottom surface of the first groove and the surface of the electrode terminal close to the electrode assembly. The first tab group is welded to the first welding part.

[0015] In this embodiment, by providing the first groove on the electrode terminal, the thickness of the electrode terminal in the welding area is reduced, and after the end cap assembly is installed on the housing, welding can be directly performed from the outside of the electrode terminal, which simplifies the assembly process and can improve the firmness of welding to reliably achieve the electrical connection between the electrode terminal and the first tab group.

[0016] In some embodiments, a second groove is provided on the surface of the end cap body away from the electrode assembly. The second groove is recessed towards the direction close to the electrode assembly. A second welding part is formed between the bottom surface of the second groove and the surface of the end cap body close to the electrode assembly. The second tab group is welded to the second welding part.

[0017] In this embodiment, by providing the second groove on the end cap body, the thickness of the end cap body in the welding area is reduced, and after the end cap assembly is installed on the housing, welding can be directly performed from the outside of the end cap body, which simplifies the assembly process and can improve the firmness of welding to reliably achieve the electrical connection between the end cap body and the second tab group.

[0018] In some embodiments, the end cap body includes a main plate and a protrusion, the protrusion is provided on a side of the main plate close to the electrode assembly, and the second groove extends into the protrusion.

[0019] This embodiment provides a protrusion that locally thickens the main plate on the side closest to the electrode assembly, bringing the second weld closer to the second tab assembly along the winding axis. This facilitates direct, single-piece connection between the second tab assembly and the end cap body, eliminating the need for adapters. This simplifies the structure and reduces the lead-out length of the second tab assembly. Furthermore, even with the locally thickened main plate, extending the second groove into the protrusion maintains an appropriate weld thickness at the second weld, improving electrical connection reliability.

[0020] In some embodiments, the battery cell further includes: a converter, the first tab group is electrically connected to the electrode terminal through the converter, and / or the second tab group is electrically connected to the end cover body through the converter.

[0021] This embodiment can reduce the requirements for the positional relationship between the first tab group and the electrode terminal, and between the second tab group and the end cover body by providing an adapter, thereby reducing the process difficulty of electrical connection; moreover, since multiple tabs are relatively fluffy, it is easier to improve the connection reliability through the adapter; in addition, it can also prevent damage to the tabs or the main body during electrical connection. For example, when welding is used, it can prevent the welding heat from causing deformation of the tabs or the main body, or the coating layer on the main body from falling off, etc.

[0022] In some embodiments, the adapter includes: a first connecting portion and a second connecting portion connected to each other, the radial size of the first connecting portion is larger than the size of the second connecting portion, the first connecting portion is electrically connected to the first tab group or the second tab group, and the second connecting portion is connected to the electrode terminal or the end cover body.

[0023] In this embodiment, the radial dimension of the first connecting portion is larger than that of the second connecting portion. This allows the first connecting portion to radially cover more tabs in the first or second tab group, increasing the radial connection length between the first connecting portion and the first or second tab group, thereby improving electrical connection reliability. For example, when welding is used for electrical connection, the welding trajectory can pass through more tabs, making the connection between the first connecting portion and each tab more secure. Furthermore, by reducing the radial dimension of the second connecting portion, it can be adapted to the connection area of the electrode terminal or the end cap body, thereby accommodating the smaller cross-sectional area of the terminal and reducing the electrical connection area on the end cap body to leave space for the layout of other components.

[0024] In some embodiments, the first tab group is a negative tab group, and the second tab group is a positive tab group.

[0025] This embodiment sets the polarities of the first tab group and the second tab group according to the commonly used materials of the tabs, end cap body, and electrode terminals, which can simplify the electrical connection process of the first tab group and the second tab group on the basis of ensuring the performance of the battery cell. Optionally, the first tab group is a positive tab group, and the second tab group is a negative tab group.

[0026] In some embodiments, the main body portion has a plurality of electrode plate layers in the radial direction. The first tab group includes a plurality of first tabs stacked, and the second tab group includes a plurality of second tabs stacked; in the radial direction, there is at least one more electrode plate layer of the same polarity between at least two adjacent first tabs in the first tab group, and / or there is at least one more electrode plate layer of the same polarity between at least two adjacent second tabs in the second tab group.

[0027] This embodiment reduces the number of tabs led out from the same electrode plate in the electrode assembly, reduces the difficulty of the tab die-cutting process, and can also improve the misalignment of multiple tabs in the tab group after winding, making it easy to control the misalignment amount within a small range, thereby increasing the effective connection part between the tab group and the electrode terminal; moreover, this structure can select to set relatively sparse tabs in the inner winding area to reduce the difficulty of tab die-cutting and improve the size and position accuracy of the tabs; in addition, this tab leading-out method can reduce the weight of the electrode assembly, thereby reducing the weight of the battery cell. The above advantages can all improve the performance of the battery cell.

[0028] In some embodiments, the number of electrode plate layers of the same polarity between every two adjacent first tabs in the first tab group is equal, and / or the number of electrode plate layers of the same polarity between every two adjacent second tabs in the second tab group is equal.

[0029] This embodiment makes multiple tabs in the tab group evenly distributed in the radial direction, making it easier to lead out the electrical energy provided by multiple tabs in the tab group. For example, if the tab group is electrically connected to the electrode terminal through an adapter, when welding is used, it is easier to control the welding track between the adapter and the tab group, ensuring the electrical connection effect between the tab group and the adapter and improving the reliability of the battery cell operation.

[0030] In some embodiments, the number of electrode plate layers between every two adjacent first tabs in the first tab group gradually decreases from the inside to the outside, and / or the number of electrode plate layers between every two adjacent second tabs in the second tab group gradually decreases from the inside to the outside.

[0031] This embodiment takes into account that the winding circumference of the electrode plate gradually decreases from the outer layer to the inner layer, the distance between adjacent two tabs near the inner layer is small, and the tabs are densely distributed. If tabs are led out from each electrode plate layer, the distance between adjacent tabs is small, the current-carrying capacity in the radial inner region of the tab group has a surplus, and it causes great difficulty for the tab die-cutting process, making it difficult to ensure the accuracy of tab die-cutting and control the misalignment of multiple tabs in the tab group.

[0032] In some embodiments, in the radial direction, the innermost first tab is led out from the n1-th tab layer of the same polarity starting from the innermost side, where n1 > 1; and / or the innermost second tab is led out from the n2-th tab layer of the same polarity starting from the innermost side, where n2 > 1.

[0033] This embodiment can increase the distance between the first tab group and the second tab group, thereby reducing the possibility of their overlap and ensuring the insulation effect between tab groups of different polarities.

[0034] In some embodiments, the first tab group and the second tab group are symmetrically arranged with respect to the winding axis.

[0035] This embodiment enables the first tab and the second tab to have the same current-carrying capacity, and is conducive to increasing the circumferential dimension of the tab group, which can improve the current-carrying capacity of the battery cell and enhance the spatial isolation effect between the first tab group and the second tab group to prevent short circuits. Moreover, if the first tab group is electrically connected to the electrode terminal through a transfer member, and the second tab group is electrically connected to the end cap body through another transfer member, the symmetrical arrangement of the first tab group and the second tab group provides a layout space for the two transfer members, preventing short circuits caused by the two transfer members being too close in the circumferential direction.

[0036] In some embodiments, the housing has a recessed portion that is recessed inward as a whole in the circumferential direction relative to the outer wall of the housing. The housing forms a bent portion at one end of the recessed portion close to the opening. The bent portion has a receiving cavity, and the outer end of the end cap body in the radial direction is embedded in the receiving cavity. The battery cell further includes a sealing member disposed between the bent portion and the end cap body.

[0037] This embodiment realizes the fixation between the end cap assembly and the housing by means of upsetting sealing. By providing a sealing member, insulation between the end cap body and the housing can be achieved. In this case, when the end cap body is used as the electrode terminal, the housing can be made non-electrified, improving the safety of the battery cell during operation.

[0038] According to the second aspect of the present application, there is provided a battery, including: the battery cell described in the above embodiments and a box body for accommodating the battery cell.

[0039] According to the third aspect of the present application, there is provided an electrical device, including the battery in the above embodiments, and the battery is used to supply electrical energy to the electrical device.

[0040] According to the fourth aspect of the present application, there is provided a manufacturing method of a battery cell, including:

[0041] Component providing step: Provide a housing, an end cap assembly, and an electrode assembly; wherein, the housing has an opening, the end cap assembly includes an end cap body and electrode terminals insulatedly connected to the end cap body, and the center line of the electrode terminals is offset by a preset distance in the radial direction of the winding structure with respect to the winding axis; the electrode assembly is in a winding structure and includes: a main body portion, a first tab group, and a second tab group, the first tab group and the second tab group have opposite polarities, and are connected to the same side of the main body portion along the winding axis of the winding structure;

[0042] End cap mounting step: Close the opening with the end cap assembly, electrically connect the first tab group to the electrode terminals, and electrically connect the second tab group to the end cap body.

[0043] According to the fifth aspect of the present application, there is provided a manufacturing device for a battery cell, including:

[0044] Component providing device, configured to provide a housing, an end cap assembly, and an electrode assembly; wherein, the housing has an opening, the end cap assembly includes an end cap body and electrode terminals insulatedly connected to the end cap body, and the center line of the electrode terminals is offset by a preset distance in the radial direction of the winding structure with respect to the winding axis; the electrode assembly is in a winding structure and includes: a main body portion, a first tab group, and a second tab group, the first tab group and the second tab group have opposite polarities, and are connected to the same side of the main body portion along the winding axis of the winding structure; and

[0045] End cap mounting device, configured to close the opening with the end cap assembly, electrically connect the first tab group to the electrode terminals, and electrically connect the second tab group to the end cap body. Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the drawings.

[0047] Figure 1 It is a schematic structural diagram of some embodiments of installing the battery of the present application in a vehicle.

[0048] Figure 2 It is an exploded view of some embodiments of the battery of the present application.

[0049] Figure 3 It is a schematic structural diagram of some embodiments of the battery cell of the present application.

[0050] Figure 4 It is a cross-sectional view of some embodiments of the battery cell of the present application in a longitudinal section.

[0051] Figure 5 ForFigure 4 Cross-sectional view of some embodiments of the middle electrode assembly in a longitudinal section.

[0052] Figure 6 is Figure 5 Schematic diagram of the end structure of the shown electrode assembly.

[0053] Figure 7 is Figure 4 Cross-sectional view of some other embodiments of the middle electrode assembly in a longitudinal section.

[0054] Figure 8 is Figure 7 Schematic diagram of the end structure of the shown electrode assembly.

[0055] Figure 9A Schematic diagram of the first tab group and the second tab group adopting a fan-shaped structure.

[0056] Figure 9B Schematic diagram of the first tab group and the second tab group adopting an equal-width structure.

[0057] Figure 10 Cross-sectional view of some other embodiments of the battery cell of the present application in a longitudinal section.

[0058] Figure 11 Schematic flow diagram of some embodiments of the manufacturing method of the electrode assembly of the present application.

[0059] Figure 12 Schematic diagram of the module composition of some embodiments of the manufacturing device of the electrode assembly of the present application.

[0060] In the drawings, the drawings are not drawn to actual scale.

[0061] Marking description:

[0062] 10. Electrode assembly; 11. Main body part; 111. Electrode sheet layer; 12. First tab group; 12'. First tab; 121. First bending part; 13. Second tab group; 13'. Second tab; 131. Second bending part; 1. First electrode sheet; 2. Second electrode sheet; 3. Separator; K. Winding axis;

[0063] 100. Battery cell; 101. Housing; 1011. Opening; 1012. Recessed part; 1013. Bending part; Q. Accommodating cavity; 102. End cap assembly; 1021. End cap body; 1021A. Main body plate; 1021B. Protruding part; 1021'. Second groove; W2. Second welding part; 1022. Electrode terminal; 1022A. First terminal part; 1022B. Second terminal part; 1022'. First groove; W1. First welding part; 103. Adapter; 1031. First connecting part; 1032. Second connecting part; 104. Sealing member;

[0064] 200. Battery; 201. Box body; 201A. Accommodating part; 201B. First cover; 201C. Second cover;

[0065] 300. Vehicle; 301. Axle; 302. Wheel; 303. Motor; 304. Controller;

[0066] 400. Manufacturing device; 410. Component providing device; 420. End cover mounting device. Detailed implementation manners

[0067] The following further describes in detail the implementation manners of the present application with reference to the drawings and embodiments. The detailed description of the following embodiments and the drawings are used to exemplarily illustrate the principle of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0068] In the description of the present application, it should be noted that unless otherwise stated, the meaning of "a plurality of" is two or more; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0069] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range. The orientation terms appearing in the following description are all the directions shown in the drawings and do not limit the specific structure of the present application.

[0070] In the description of the present application, it should also be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" 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 directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0071] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least some embodiments of the present application. The phrase appears in various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0072] In the description of the embodiments of the present application, the term "plurality" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0073] The present application uses descriptions of orientation or positional relationships indicated by "upper", "lower", "top", "bottom", "front", "rear", "inner", and "outer", etc. This is only for the convenience of describing the present application, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present application.

[0074] The battery cell may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, etc., and the embodiments of the present application are not limited thereto. The battery cell may be in a cylindrical shape, a flat shape, a cuboid shape, or other shapes, etc., and the embodiments of the present application are not limited thereto either. Generally, the battery cell is divided into three types according to the encapsulation method: a cylindrical battery cell, a square battery cell, and a soft-pack battery cell, and the embodiments of the present application are not limited thereto.

[0075] Currently, the battery cell generally includes a housing and an electrode assembly accommodated in the housing, and an electrolyte is filled in the housing. The electrode assembly is mainly formed by laminating or winding a first electrode sheet and a second electrode sheet with opposite polarities, and a separator is usually provided between the first electrode sheet and the second electrode sheet. The parts of the first electrode sheet and the second electrode sheet coated with the active material constitute the main body of the electrode assembly, and the parts of the first electrode sheet and the second electrode sheet not coated with the active material respectively constitute the first electrode tab and the second electrode tab. In a lithium-ion battery, the first electrode sheet may be a positive electrode sheet, including a positive electrode current collector and positive electrode active material layers provided on both sides of the positive electrode current collector. The material of the positive electrode current collector may be, for example, aluminum, and the positive electrode active material may be, for example, lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc.; the second electrode sheet may be a negative electrode sheet, including a negative electrode current collector and negative electrode active material layers provided on both sides of the negative electrode current collector. The material of the negative electrode current collector may be, for example, copper, and the negative electrode active material may be, for example, graphite or silicon, etc. The first electrode tab and the second electrode tab may be located at one end of the main body together or at both ends of the main body respectively. During the charging and discharging process of the battery cell, the positive electrode active material and the negative electrode active material react with the electrolyte, and the electrode tabs are connected to the terminals to form a current loop.

[0076] Current battery cells usually have a first electrode terminal and a second electrode terminal with opposite polarities, which are used to connect to an electrical circuit for power supply. The first tab is electrically connected to the first electrode terminal, and the second tab is electrically connected to the second electrode terminal. For example, for a cylindrical battery cell, since the end area of the battery cell is small, the second tab and the second electrode terminal are respectively arranged at both ends of the battery cell. Correspondingly, the first tab and the second tab are respectively led out from both ends of the electrode assembly. The inventors have found in practice that the tabs and electrode terminals at each end will occupy a certain space for electrical connection, which requires more space in the height direction of the battery cell, resulting in an increase in the overall volume of the battery cell and affecting the overall energy density of the battery cell.

[0077] In order to improve the energy density of the battery cell, the inventors thought of arranging the first electrode terminal and the second electrode terminal on the same end of the battery cell. Correspondingly, the first tab and the second tab are led out from the same end of the electrode assembly. However, this setting method faces the following two problems.

[0078] 1. Space layout problem: It will be relatively crowded to set two electrode terminals on the end cap at the same time, and the insulation problem of the two electrode terminals also needs to be considered. In addition, a liquid injection hole and a pressure relief structure need to be arranged on the end cap, and temperature acquisition components, bus bars between battery cells and various wires need to be arranged. It is difficult to carry out space layout when the area of the end cap is small.

[0079] 2. Insulation problem: The first electrode terminal and the second electrode terminal arranged on the same end of the battery cell need to be reliably insulated, and the first tab and the second tab led out from the same end of the electrode assembly also need to consider insulation problems when being led out to improve the working reliability of the battery cell.

[0080] Based on the discovery of the above problems, the inventors of the present application improved the way of outputting electrical energy of the battery cell starting from the idea of improving the energy density of the battery cell and improving the space layout on the end cap.

[0081] The end cap assembly includes an end cap body and an electrode terminal, and the electrode terminal is insulated and connected to the end cap body; the electrode assembly is in a wound structure and includes: a main body part, a first tab group and a second tab group. The first tab group and the second tab group have opposite polarities and are connected to the same side of the main body part along the winding axis of the wound structure; the first tab group is electrically connected to the electrode terminal, and the center line of the electrode terminal is offset by a preset distance in the radial direction of the wound structure relative to the winding axis, and the second tab group is electrically connected to the end cap body. Such a battery cell can improve the overall energy density, simplify the structure and assembly process of the battery cell by omitting one electrode terminal, and leave a large space on the end cap body, leaving sufficient space for arranging various components on the end cap.

[0082] The battery cell of the embodiment of the present application is applicable to a battery and an electrical device using the battery.

[0083] The electrical device can be a mobile phone, a portable device, a laptop computer, a battery car, an electric vehicle, a ship, a spacecraft, an electric toy, an electric tool, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc., and the electric toy includes a fixed or mobile electric toy. For example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc., and the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool. For example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, and a planer.

[0084] As Figure 1 shown, the electrical device can be a vehicle 300, such as a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc.; or the electrical device can also be a drone or a ship, etc. Specifically, the vehicle 300 may include an axle 301, wheels 302 connected to the axle 301, a motor 303, a controller 304, and a battery 200. The motor 303 is used to drive the axle 301 to rotate, and the controller 304 is used to control the operation of the motor 303. The battery 200 can be disposed at the bottom, head, or tail of the vehicle 300 to provide electrical energy for the operation of the motor 303 and other components in the vehicle.

[0085] As Figure 2 shown, the battery 200 includes a box body 201 and a battery cell 100. In the battery 200, the battery cell 100 can be one or multiple. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, parallel, or in a series-parallel combination. The series-parallel combination means that there are both series and parallel connections among the multiple battery cells 100. It can be that multiple battery cells 100 are first connected in series, parallel, or in a series-parallel combination to form a battery module, and then multiple battery modules are connected in series, parallel, or in a series-parallel combination to form a whole and are accommodated in the box body 201. It can also be that all the battery cells 100 are directly connected in series, parallel, or in a series-parallel combination together, and then the whole formed by all the battery cells 100 is accommodated in the box body 201.

[0086] The interior of the box body 201 is hollow and is used to accommodate one or more battery cells 100. According to the shape, quantity, combination method, and other requirements of the accommodated battery cells 100, the box body 201 can also have different shapes and sizes. For example, the box body 201 may include: a receiving portion 201A, a first cover body 201B, and a second cover body 201C. Both ends of the receiving portion 201A have openings, and the first cover body 201B and the second cover body 201C are respectively used to close the openings at both ends of the receiving portion 201A. Figure 2According to the arrangement of multiple battery cells 100, the accommodating part 201A has a rectangular cylindrical structure.

[0087] The battery cell 100 can be, for example, a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, or a magnesium-ion battery, etc.

[0088] In some embodiments, as Figure 3 and Figure 4 shown, the battery cell 100 includes a housing 101, an end cap assembly 102, and an electrode assembly 10. The housing 101 has an opening 1011; the end cap assembly 102 is used to close the opening 1011. The end cap assembly 102 includes an end cap body 1021 and an electrode terminal 1022, and the electrode terminal 1022 is insulatingly connected to the end cap body 1021. The electrode assembly 10 is disposed inside the housing 101. The electrode assembly 10 has a wound structure and includes: a main body portion 11, a first tab group 12, and a second tab group 13. The first tab group 12 and the second tab group 13 have opposite polarities and are connected to the same side of the main body portion 11 along the winding axis K of the wound structure. Among them, the first tab group 12 is electrically connected to the electrode terminal 1022, and the center line of the electrode terminal 1022 is offset by a preset distance in the radial direction of the wound structure with respect to the winding axis K. The second tab group 13 is electrically connected to the end cap body 1021.

[0089] Among them, the housing 101 has a hollow structure for accommodating the electrode assembly 10, and the housing 101 has an opening 1011. The end cap body 1021 is used to cover the opening 1011. For a cuboid battery cell 100, the end cap body 1021 has a rectangular plate-like structure; for a cylindrical battery cell 100, the end cap body 1021 has a disc-like structure.

[0090] The insulating connection of the electrode terminal 1022 to the end cap body 1021 can be realized in two forms. For example, an insulating layer is coated on the portion where the electrode terminal 1022 is connected to the end cap body 1021, or the electrode terminal 1022 includes a conductive part and an insulating member 1022C, and the insulating member 1022C is disposed between the conductive part and the end cap body 1021 to play an insulating role. Since the first tab group 12 is electrically connected to the electrode terminal 1022 and the second tab group 13 is electrically connected to the end cap body 1021, and the end cap body 1021 acts as the electrode terminal, insulatingly connecting the electrode terminal 1022 to the end cap body 1021 can achieve the insulation of the positive and negative electrode terminals and improve the reliability of the operation of the battery cell 100. The "electrical connection" here includes both direct connection and indirect connection cases.

[0091] The electrode assembly 10 has a wound structure and includes: a main body portion 11, and a first tab group 12 and a second tab group 13 with opposite polarities. At least one of the first tab group 12 and the second tab group 13 can be provided.

[0092] Specifically, the electrode assembly 10 is formed by winding a first pole piece 1 and a second pole piece 2 with opposite polarities. The shapes of the first pole piece 1 and the second pole piece 2 are basically the same and can be strip-shaped structures. The first pole piece 1 includes a pole piece body 11' and at least one first pole ear group 12. The first pole ear group 12 includes a plurality of first pole ears 12' arranged in a stacked manner, and the plurality of first pole ears 12' protrude from the pole piece body 11'; the second pole piece 2 includes a pole piece body 11' and at least one second pole ear group 13. The second pole ear group 13 includes a plurality of second pole ears 13' arranged in a stacked manner, and the plurality of second pole ears 13' protrude from the pole piece body 11'. Different active materials are coated on the pole piece bodies 11' of the first pole piece 1 and the second pole piece 2. Among them, the stacked arrangement means that the plurality of pole ears in the same pole ear group are distributed along the same radial direction of the winding structure, that is, the projections of the plurality of pole ears in the radial direction have an overlapping area. Whether the plurality of pole ears are aligned or deviated along the side part in the winding direction is within the scope protected by this application.

[0093] The first pole piece 1 and the second pole piece 2 are wound around the winding axis K so that their respective pole piece bodies 11' form a main body part 11. The main body part 11 can be a cylinder, a flat body, a cuboid or other shapes. For example, the first pole piece 1 is a positive electrode piece and the second pole piece 2 is a negative electrode piece; or the first pole piece 1 is a negative electrode piece and the second pole piece 2 is a positive electrode piece.

[0094] The center line of the electrode terminal 1022 is offset by a preset distance in the radial direction of the winding structure relative to the winding axis K. For example, the cross-section of the electrode terminal 1022 can be circular, elliptical, triangular, rectangular or other polygons, etc. No matter what shape the electrode terminal 1022 adopts, the center line of the electrode terminal 1022 is arranged to deviate from the winding axis K in the radial direction of the winding structure.

[0095] The circumferential position of the electrode terminal 1022 on the end cover body 1021 can be determined according to the circumferential position led out by the first pole ear group 12. The preset distance of the electrode terminal 1022 offset in the radial direction can be determined according to the radial position and size of the first pole ear group 12 and the cross-sectional size of the electrode terminal 1022. Specifically, the electrode terminal 1022 is radially opposite to the first pole ear group 12 as a whole to facilitate electrical connection and increase the effective connection length of the electrode terminal 1022 and the first pole ear group 12 in the radial direction, improving the overcurrent capacity; on this basis, the electrode terminal 1022 is aligned with the middle area of the first pole ear group 12 in the radial direction, which can simultaneously reduce the distance for the first pole ears 12' in the inner and outer radial regions of the first pole ear group 12 to conduct electrons to the middle, improving the electron transfer speed and thus improving the conductivity. On the basis of considering the conductivity, the cross-sectional size of the electrode terminal 1022 also needs to be comprehensively considered, and it is necessary to ensure that the side wall of the electrode terminal 1022 does not exceed the side wall of the end cover body 1021.

[0096] In this embodiment, the first tab group 12 and the second tab group 13 are led out from the same end of the main body 11, only an electrical connection space needs to be reserved at one end of the electrode assembly 10, and it also eliminates the need to separately provide electrode terminals 1022 at both ends of the battery cell 100, which can effectively improve the overall energy density of the battery cell 100. When the capacity of the battery cell 100 is certain, it can reduce the volume of the battery cell 100, making it easier to layout the battery 200 in the electrical device.

[0097] Moreover, this kind of battery cell 100 is only provided with one electrode terminal 1022. The first tab group 12 is electrically connected to the electrode terminal 1022, and the second tab group 13 is directly electrically connected to the end cap body 1021, which can simplify the structure and assembly process of the battery cell 100. By eliminating one electrode terminal, a larger space can be left on the end cap body 1021. The center line of the electrode terminal 1022 is offset by a preset distance in the radial direction of the winding structure relative to the winding axis K, which can further increase the space on the end cap body 1021 on one side of the electrode terminal 1022. On the one hand, it is easy to layout the liquid injection hole and the pressure relief structure on the end cap body 1021, and it also leaves sufficient space for arranging the temperature acquisition component, the bus bar between battery cells 100 and various wires; on the other hand, the position of the electrode terminal 1022 can be flexibly adjusted according to the position of the first tab group 12, which is also beneficial to increasing the cross-sectional area of the electrode terminal 1022 to increase the overcurrent capacity of the battery cell 100. This design has greater advantages when the area of the end cap body 1021 is small.

[0098] In some embodiments, the first tab group 12 and the second tab group 13 are arranged at intervals along the circumferential direction of the winding structure.

[0099] Since the first tab group 12 and the second tab group 13 are arranged at intervals along the circumferential direction of the winding structure, the first tab group 12 and the second tab group 13 extend along a partial circumferential direction of the winding structure. Therefore, between every two adjacent first tabs 12' in the first tab group 12, they are discretely arranged on the electrode plate body 11' along the winding direction, and between every two adjacent second tabs 13' in the second tab group 13, they are discretely arranged on the electrode plate body 11' along the winding direction.

[0100] In this embodiment, the first tab group 12 is entirely located on one side of the winding axis K. When electrically connecting the first tab group 12 to the electrode terminal 1022, the center line of the electrode terminal 1022 can be offset in the radial direction of the winding structure relative to the winding axis K. Moreover, this kind of structure can separate the first tab group 12 and the second tab group 13 in space to avoid short circuit, and it may also enable the electrolyte to infiltrate into the interior of the main body 11 through the interval area, so that during the charging and discharging process of the battery cell 100, the electrolyte can fully react with the active substances on the first electrode plate 1 and the second electrode plate 2.

[0101] In some embodiments, as Figure 4 shown, a first groove 1022' is provided on the surface of the electrode terminal 1022 away from the electrode assembly 10. The first groove 1022' is recessed in the direction close to the electrode assembly 10. A first welding portion W1 is formed between the bottom surface of the first groove 1022' and the surface of the electrode terminal 1022 close to the electrode assembly 10. The first tab group 12 is welded to the first welding portion W1.

[0102] Among them, the shape and size of the first groove 1022' can be set according to the welding area. For example, laser welding can be used between the first tab group 12 and the electrode terminal 1022. The thickness of the first welding portion W1 should ensure that the welding energy can penetrate to achieve reliable fixation.

[0103] In this embodiment, by providing the first groove 1022' on the electrode terminal 1022, the thickness of the electrode terminal 1022 in the welding area is reduced. After the end cap assembly 102 is installed on the housing 101, welding can be directly performed from the outside of the electrode terminal 1022, simplifying the assembly process and improving the welding firmness to reliably achieve the electrical connection between the electrode terminal 12 and the first tab group 12.

[0104] In some embodiments, as Figure 4 shown, a second groove 1021' is provided on the surface of the end cap body 1021 away from the electrode assembly 10. The second groove 1021' is recessed in the direction close to the electrode assembly 10. A second welding portion W2 is formed between the bottom surface of the second groove 1021' and the surface of the end cap body 1021 close to the electrode assembly 10. The second tab group 13 is welded to the second welding portion W2.

[0105] Among them, the shape and size of the second groove 1021' can be set according to the welding area. If the second tab group 13 is directly electrically connected to the end cap body 1021, the circumferential extension length of the second groove 1021' can be designed to be not less than the circumferential dimension of the second tab group 13 to increase the effective connection length between the second tab group 13 and the end cap body 1021 and increase the current-carrying capacity. Since a plurality of second tabs 13' of the second tab group 13 are connected together in the radial direction, the radial extension length of the second groove 1021' can be less than the radial dimension of the second tab group 13 to ensure the strength of the end cap body 1021.

[0106] For example, laser welding can be used between the second tab group 13 and the end cap body 1021. The thickness of the second welding portion W2 should ensure that the welding energy can penetrate to achieve reliable fixation.

[0107] In this embodiment, by providing a second groove 1021' on the end cap body 1021, the thickness of the end cap body 1021 in the welding area is reduced, enabling direct welding from the outside of the end cap body 1021 after the end cap assembly 102 is installed on the housing 101. This simplifies the assembly process and improves the welding firmness, reliably achieving the electrical connection between the end cap body 1021 and the second tab group 13.

[0108] In some embodiments, as Figure 4 shown, the end cap body 1021 includes a main body plate 1021A and a protruding portion 1021B. The protruding portion 1021B is connected to the main body plate 1021A on the side close to the electrode assembly 10, and the second groove 1021' extends into the protruding portion 1021B.

[0109] In this embodiment, by providing the protruding portion 1021B, a part of the main body plate 1021A on the side close to the electrode assembly 10 is locally thickened, making the second welding portion W2 closer to the second tab group 13 in the direction of the winding axis K. This facilitates directly connecting the second tab group 13 to the end cap body 1021 alone and eliminating the adapter 103, simplifies the structure, and can also reduce the lead-out length of the second tab group 13. Moreover, when a part of the main body plate 1021A is locally thickened, by extending the second groove 1021' into the protruding portion 1021B, the second welding portion W2 can also be maintained at an appropriate welding thickness, improving the electrical connection reliability.

[0110] In some embodiments, the battery cell 100 further includes: an adapter 103, the first tab group 12 is electrically connected to the electrode terminal 1022 through the adapter 103, and / or the second tab group 13 is electrically connected to the end cap body 1021 through the adapter 103. For example, the electrical connection can be achieved by welding or riveting.

[0111] For example, when using the welding method, the first tab group 12 and / or the second tab group 13 can be welded to the adapter 103 first. After installing the end cap assembly 102, the electrode terminal 1022 is electrically connected to the adapter 103 from the outside of the end cap assembly 102, and the end cap body 1021 is electrically connected to the adapter 103.

[0112] Optionally, the first tab group 12 can also be directly electrically connected to the electrode terminal 1022, and the second tab group 13 can also be directly electrically connected to the end cap body 1021.

[0113] Whether to provide the adapter 103 for the first tab group 12 and the second tab group 13 can be determined according to the connection requirements.

[0114] In this embodiment, by providing the adapter 103, the requirements for the positional relationship between the first tab group 12 and the electrode terminal 1022, and between the second tab group 13 and the end cap body 1021 can be reduced, thereby reducing the process difficulty of electrical connection. Moreover, since multiple tabs are relatively fluffy, it is easier to improve the connection reliability through the adapter 103 to increase the current-carrying capacity of the inner and outer ring tabs. For example, when performing electrical connection by welding, the welding trajectory between the adapter 103 and the tab group can be controlled to improve the firmness of welding. Additionally, damage to the tabs or the main body 11 during electrical connection can be prevented. For example, when welding is used, it can prevent the welding energy from burning the tabs, deforming the main body 11, or causing the coating layer on the main body 11 to peel off, etc.

[0115] In some embodiments, as Figure 4 shown, the adapter 103 includes a first connecting portion 1031 and a second connecting portion 1032 that are connected to each other. The dimension of the first connecting portion 1031 in the radial direction is greater than that of the second connecting portion 1032.

[0116] For the adapter 103 connected between the first tab group 12 and the electrode terminal 1022, the first connecting portion 1031 is electrically connected to the first tab group 12, and the second connecting portion 1032 is electrically connected to the electrode terminal 1022; and / or for the adapter 103 connected between the second tab group 13 and the end cap body 1021, the first connecting portion 1031 is electrically connected to the second tab group 13, and the second connecting portion 1032 is connected to the end cap body 1021.

[0117] For example, the first connecting portion 1031 can adopt a sheet-like structure and extend in a plane perpendicular to the winding axis K, which can increase the connection area with the first tab group 12 or the second tab group 13 to improve the connection reliability. One end of the second connecting portion 1032 can be connected to the first connecting portion 1031, and the other end of the second connecting portion 1032 is connected to the electrode terminal 1022.

[0118] Considering that the size of the electrode terminal 1022 is small, the electrical connection between the first tab group 12 and the electrode terminal 1022 through the adapter 103 can improve the reliability of power transmission. The size of the first groove 1022' can be set according to the adapter 103. If the second tab group 13 is electrically connected to the end cap body 1021 through the adapter 103, the size of the second groove 1021' is designed according to the adapter 103.

[0119] In this embodiment, the first connecting portion 1031 has a larger radial dimension than the second connecting portion 1032, enabling the first connecting portion 1031 to cover more tabs in the first tab group 12 or the second tab group 13 in the radial direction, increasing the connection length between the first connecting portion 1031 and the first tab group 12 or the second tab group 13 in the radial direction, and improving the reliability of the electrical connection. For example, when performing electrical connection by welding, the welding track can pass through more tabs, making the connection between the first connecting portion 1031 and each tab more secure. Moreover, by reducing the radial dimension of the second connecting portion 1032, it can be adapted to the connection area with the electrode terminal 1022 or the end cap body 1021, thereby adapting to the smaller cross-sectional area of the electrode terminal 1022 and reducing the electrical connection area on the end cap body 1021 to leave space for arranging other components.

[0120] In some embodiments, the first tab group 12 is a negative tab group, and the second tab group 13 is a positive tab group.

[0121] Generally, the positive current collector is made of aluminum foil, and the negative current collector is made of copper foil. Correspondingly, the first tab group 12 is made of copper material, and the second tab group 13 is made of aluminum material.

[0122] To ensure the strength of the end cap body 1021, it can be made of aluminum alloy material, so that the aluminum second tab group 13 can be directly welded to the end cap body 1021.

[0123] The electrode terminal 1022 is negative and is connected to the copper first tab group 12. To reduce weight and cost, multiple battery cells 100 are generally connected by an aluminum bus bar. Therefore, the part of the electrode terminal 1022 connected to the external circuit is preferably made of aluminum material. However, the part of the electrode terminal 1022 connected to the copper first tab group 12 still needs to be made of copper material.

[0124] For this reason, as Figure 4 described, the electrode terminal 1022 can be designed as a composite electrode terminal, which includes a first terminal portion 1022A and a second terminal portion 1022B. The first terminal portion 1022A and the second terminal portion 1022B are connected along the direction of the winding axis K. For example, they can be connected by friction welding or other methods. The second terminal portion 1022B is located between the first terminal portion 1022A and the electrode assembly 10. The first terminal portion 1022A is made of aluminum material and is used to connect to the external circuit of the battery cell 100; the second terminal portion 1022B is made of copper material and is electrically connected to the first tab group 12 or the adapter 103, for example, by welding or other methods.

[0125] Specifically, the first terminal portion 1022A is coaxially connected to the second terminal portion 1022B. The first terminal portion 1022A can adopt a columnar structure, such as Figure 4As shown, the second terminal portion 1022B can be designed as a flat plate shape, and the second terminal portion 1022B is connected to the second connection portion 1032 of the adapter 103; alternatively, a partial area of the plate-shaped structure of the second terminal portion 1022B can also protrude towards the electrode assembly 10 to be capable of connecting to the first tab group 12, so as to eliminate the need to provide the adapter 103.

[0126] In order to insulatively connect the conductive part of the electrode terminal 1022 to the end cap body 1021, the electrode terminal 1022 can further include an insulating member 1022C. The insulating member 1022C can be in an annular structure and sleeved outside the first terminal portion 1022A and the second terminal portion 1022B.

[0127] This embodiment sets the polarities of the first tab group 12 and the second tab group 13 according to the materials commonly used for the tabs, the end cap body 1021, and the electrode terminal 1022, and can simplify the electrical connection process of the first tab group 12 and the second tab group 13 on the basis of ensuring the performance of the battery cell 100. Optionally, the first tab group 12 is a positive tab group, and the second tab group 13 is a negative tab group.

[0128] In some embodiments, as Figures 5 to 8 shown, the main body portion 11 has a plurality of electrode plate layers 111 in the radial direction. The first tab group 12 includes a plurality of first tabs 12' stacked. The second tab group 13 includes a plurality of second tabs 13' stacked. In the radial direction, between at least two adjacent first tabs 12' in the first tab group 12, there is one or more electrode plate layers 111 of the same polarity spaced apart, and / or between at least two adjacent second tabs 13' in the second tab group 13, there is one or more electrode plate layers 111 of the same polarity spaced apart.

[0129] Among them, the electrode plate body 11' of the first electrode plate 1 has a plurality of electrode plate layers 111 in the radial direction after winding. The electrode plate body 11' of the second electrode plate 2 also has a plurality of electrode plate layers 111 in the radial direction after winding. The electrode plate layers 111 of the first electrode plate 1 and the second electrode plate 2 are alternately arranged in the radial direction, and all the electrode plate layers 111 of the first electrode plate 1 and all the electrode plate layers of the second electrode plate 2 together form the main body portion 11. The first electrode plate 1 only leads out the first tab 12' in some of the electrode plate layers 111 to form the first tab group 12, and the second electrode plate 2 only leads out the second tab 13' in some of the electrode plate layers 111 to form the second tab group 13.

[0130] This embodiment reduces the number of tab leads on the same electrode tab in the electrode assembly 10, reduces the difficulty of the die-cutting tab process, and can also improve the misalignment of multiple tabs in the tab group after winding, making it easy to control the misalignment amount within a small range, thereby increasing the effective connection portion between the tab group and the electrode terminal 1022. Moreover, this structure can select to set relatively sparse tabs in the inner winding area to reduce the difficulty of die-cutting tabs and improve the size and position accuracy of the tabs. In addition, this tab lead-out method can reduce the weight of the electrode assembly 10, thereby reducing the weight of the battery cell 100. The above advantages can all improve the performance of the battery cell 100.

[0131] In some embodiments, such as Figure 5 and Figure 6 , the number of electrode tab layers 111 spaced between every two adjacent first tabs 12' in the first tab group 12 gradually decreases from the inside to the outside, and / or the number of electrode tab layers 111 spaced between every two adjacent second tabs 13' in the second tab group 13 gradually decreases from the inside to the outside.

[0132] Figure 6 The solid arcs in the first tab group 12 represent the led-out first tabs 12', and the dashed arcs represent the electrode tab layers 111 where the first tabs 12' are not led out; the solid arcs in the second tab group 13 represent the led-out second tabs 13', and the dashed arcs represent the electrode tab layers 111 where the second tabs 13' are not led out. "From the inside to the outside" is with respect to the radial direction of the winding structure, and "gradually decreasing" includes decreasing according to the rule of an arithmetic sequence. For example, the number of electrode tab layers 111 of the same polarity spaced between every two adjacent tabs from the inside to the outside is successively: 4 layers, 3 layers, 2 layers, 1 layer, and the electrode tab layers 111 in the innermost area are not all shown. Optionally, "gradually decreasing" can also include decreasing according to any other rule.

[0133] Optionally, the spacing between every two adjacent first tabs 12' in the first tab group 12 is consistent along the winding direction, and / or the spacing between every two adjacent second tabs 13' in the second tab group 13 is consistent along the winding direction. On the basis of satisfying the stacked arrangement of multiple tabs in the tab group, this structure can, by design, keep the spacing between adjacent tabs in the tab group consistent, which can reduce the die-cutting process difficulty while reducing the number of tabs. Only a tool of the same size needs to be used for die-cutting, which can improve the production efficiency of the electrode assembly 10.

[0134] This embodiment takes into account that the winding circumference of the electrode tab gradually decreases from the outer layer to the inner layer. The spacing between two adjacent tabs near the inner layer is small, and the tabs are densely distributed. If tabs are led out from each electrode tab layer 111, the spacing between adjacent tabs is small, the current-carrying capacity in the radial inner area of the tab group has a surplus, and it causes great difficulty for the die-cutting tab process, making it difficult to ensure the accuracy of die-cutting tabs and also difficult to control the misalignment of multiple tabs in the tab group.

[0135] This tab extraction method allows the multiple tabs in the tab group to be gradually denser in the radial direction from the inside to the outside. While reducing the number of tabs, the spacing between adjacent tabs in the inner and outer rings is balanced based on the distribution characteristics of the tabs from the inner layer to the outer layer, making the inner layer tabs more sparsely distributed. This effectively reduces the difficulty of the tab die-cutting process while ensuring current flow capacity, improves the accuracy of the tab die-cutting, and easily controls the misalignment of the multiple tabs in the tab group within a small range after winding. Furthermore, it can effectively reduce the weight of the electrode assembly 10.

[0136] In some embodiments, the free ends of the plurality of first tabs 12 ′ in each first tab group 12 are close together and connected to the adapter 103 ; and / or the free ends of the plurality of second tabs 13 ′ in each second tab group 13 are close together and connected to the adapter 103 .

[0137] After the free ends of the multiple tabs in the same tab group are brought together, they can be connected together first, for example, by welding, etc., and then the length section of the multiple tabs connected together can be connected to the adapter 103, and finally the adapter 103 can be bent to facilitate the connection of the electrode terminal 1022. Since the distances between the multiple tabs and the close-up position are different, in order to facilitate the connection of the multiple tabs, the multiple tabs can be set to different lengths. For the electrode assembly 10 in which the number of electrode layers 111 between each two adjacent tabs in the tab group gradually decreases from the inside to the outside, since the multiple tabs are unevenly distributed in the radial direction, this method connects the multiple tabs together with a simpler process, which can reduce the requirements for the positioning accuracy of the tab ends during connection. This method of connecting the tab group and the adapter 103 can eliminate the tab flattening process and directly connect multiple tabs in the same tab group together and then connect them to the adapter 103. It can simplify the assembly process of the battery cell 100 and reduce the requirements for the positioning accuracy of the tab ends when connecting the tab group and the adapter 103, thereby improving the production efficiency of the battery cell 100.

[0138] In some embodiments, as Figure 7 and Figure 8 The number of electrode layers 111 of the same polarity between each two adjacent first electrode tabs 12' in the first electrode tab group 12 is equal, and / or the number of electrode layers 111 of the same polarity between each two adjacent second electrode tabs 13' in the second electrode tab group 13 is equal.

[0139] Figure 8In the first tab group 12, the solid arcs represent the first tabs 12' that are led out, and the dashed arcs represent the tab layers 111 where the first tabs 12' are not led out; in the second tab group 13, the solid arcs represent the second tabs 13' that are led out, and the dashed arcs represent the tab layers 111 where the first tabs 12' are not led out. For example, the number of tab layers 111 between every two adjacent tabs can be 1 layer, 2 layers, 3 layers or more layers.

[0140] This embodiment makes the multiple tabs in the tab group evenly distributed in the radial direction, making it easier to lead out the electrical energy provided by the multiple tabs in the tab group. For example, if the tab group is electrically connected to the electrode terminal through the adapter 103, when welding is used, it is easier to control the welding trajectory between the adapter 103 and the tab group, ensuring the electrical connection effect between the tab group and the adapter 103, and improving the reliability of the operation of the battery cell 100.

[0141] In some embodiments, the free ends of the multiple first tabs 12' in each first tab group 12 are all formed into a first bending portion 121 by flattening, and the first bending portions 121 of the multiple first tabs 12' are respectively connected to the corresponding adapter 103; and / or the free ends of the multiple first tabs 12' in each second tab group 12 are all formed into a second bending portion 131 by flattening, and the second bending portions 131 of the multiple first tabs 12' are respectively connected to the corresponding adapter 103.

[0142] Among them, flattening is to apply an external force to the tabs along the circumferential direction of the winding structure through a tooling, causing the tabs to bend and deform, so that two adjacent tabs in the radial direction are more compact, thereby facilitating the connection between the tab group and the adapter 103 or the electrode terminal 1022.

[0143] For the electrode assembly 10 where the number of tab layers 111 between every two adjacent tabs in the tab group is equal, the multiple tabs in the tab group are evenly distributed in the radial direction. Through the flattening process, the multiple tabs can form connecting portions with the same length as the welding plane, and are connected to the adapter 103 through the connecting portions of the multiple tabs respectively.

[0144] This embodiment forms connecting portions by flattening the free ends of the multiple tabs in the tab group, and connects to the adapter 103 through the multiple connecting portions, which can increase the radial length of the electrical connection between the adapter 103 and the tab group. When using welding for connection, it is easy to make the welding trajectory cover all the tabs in the tab group, improving the welding reliability, and thus improving the performance of the battery cell 100.

[0145] In some embodiments, in the radial direction, the first pole lug 12' located at the innermost side is led out from the n1th pole piece layer 111 of the same polarity from the innermost side, n1>1, that is, the n1-1th pole piece layer on the innermost side of the first pole piece 1 has no first pole lug 12'; and / or the second pole lug 13' located at the innermost side is led out from the n2th pole piece layer 111 of the same polarity from the innermost side, n2>1, that is, the n2-1th pole piece layer 111 on the innermost side of the second pole piece 2 has no second pole lug 13'.

[0146] This embodiment can increase the distance between the first tab group 12 and the second tab group 13 to reduce the possibility of overlap between the two and ensure the insulation effect between the tab groups of different polarities.

[0147] In some embodiments, the shell 101 has a recessed portion 1012, which is recessed inward as a whole relative to the outer wall of the shell 11 in the circumferential direction. The shell 101 forms a bent portion 1013 at one end of the recessed portion 1012 close to the opening 1011. The bent portion 1013 has a accommodating cavity Q, and the radial outer end of the end cover body 1021 is embedded in the accommodating cavity Q. The battery cell 100 also includes a seal 104, which is arranged between the bent portion 1013 and the end cover body 1021.

[0148] The recessed portion 1012 may extend along the entire circumference of the housing 101, or a plurality of recessed portions 1012 may be spaced apart around the circumference of the housing 101. The seal 104 may be a sealing ring having a C-shaped cross-section, which is fitted over the outer end of the end cap body 1021 to insulate the end cap body 1021 from the housing 101. Optionally, an extension may be provided at one end of the C-shaped structure proximal to the electrode assembly 10, extending toward the electrode assembly 10 to insulate the recessed portion 1012 from the internal structure of the battery cell 10. For example, the seal 104 may be made of a material such as rubber.

[0149] When fixing the end cover assembly 102, the seal 104 is first sleeved on the radial outer end of the end cover assembly 102, and the end cover assembly 102 is placed into the shell 101 from the opening 1011, the end cover assembly 102 is resting on the recessed portion 1012, and then the shell 101 is bent at one end of the recessed portion 1012 close to the opening 1011 to form a bent portion 1013, and the bent portion 1013 is wrapped around the outside of the seal 104.

[0150] This embodiment adopts an upsetting method to achieve the fixation between the end cover assembly 102 and the shell 101. By setting the seal 104, insulation between the end cover body 1021 and the shell 101 can be achieved. In this way, when the end cover body 1021 is used as an electrode terminal, the shell 101 can be de-energized, thereby improving the safety of the battery cell 100.

[0151] In some embodiments, such as Figure 9A and 9B shown, the first tab group 12 and the second tab group 13 are symmetrically arranged with respect to the winding axis K. Among them, "symmetrically arranged" includes that the first tab group 12 and the second tab group 13 have the same shape and are centrosymmetric with respect to the winding axis K in position.

[0152] Such as Figure 9A shown, the widths of the plurality of first tabs 12' in the first tab group 12 gradually increase from the inside to the outside in the winding direction, making the first tab group 12 have a fan-shaped structure; and / or the widths of the plurality of second tabs 13' in the second tab group 13 gradually increase from the inside to the outside in the winding direction, making the second tab group 13 have a fan-shaped structure. This structure makes the widths of the plurality of tabs in the tab group gradually increase from the inside to the outside in the radial direction. On the basis that the distance between every two adjacent tabs is evenly distributed, by increasing the width of the outer-layer tabs in the winding direction, the effective contact area when the tab group is connected to the electrode terminal 1022 can be increased, the over-current capacity can be increased, and thus the performance of the battery cell 100 can be improved.

[0153] Figure 9B shown, the widths of the plurality of first tabs 12' in the first tab group 12 are equal; and / or the widths of the plurality of second tabs 13' in the second tab group 13 are equal.

[0154] The tab group has a structure similar to a rectangle, except that the two opposite sides of the rectangle in the radial direction are arc-shaped. The same side ends of the plurality of tabs in the tab group are aligned to increase the effective contact area when the tab group is electrically connected to the electrode terminal 1022 and improve the over-current capacity. Optionally, a positional deviation of the same side ends of the plurality of tabs in the tab group in the winding direction is also within the protection scope of this solution. This structure makes the widths of the plurality of tabs in the tab group equal, which can reduce the difficulty of die-cutting the tabs, is easy to ensure the dimensions of the tabs, and is easy to ensure the alignment degree of the plurality of tabs during winding, thereby reducing the process difficulty of manufacturing the electrode assembly 10.

[0155] This embodiment enables the first electrode sheet 1 and the second electrode sheet 2 to have the same over-current capacity, is conducive to increasing the circumferential dimension of the tab group, can improve the over-current capacity of the battery cell 100, and can improve the spatial isolation effect between the first tab group 12 and the second tab group 13 to prevent short circuits. Moreover, if the first tab group 12 is electrically connected to the electrode terminal 1022 through a transfer member 103, and the second tab group 13 is electrically connected to the end cap body 1021 through another transfer member 103, the symmetrical arrangement of the first tab group 12 and the second tab group 13 provides a layout space for the two transfer members 103, and can prevent short circuits caused by the two transfer members 103 being too close in the circumferential direction.

[0156] Two specific embodiments of the battery cell 100 will be given below.

[0157] In some embodiments, as Figures 4 to 9B shown, the battery cell 100 includes a housing 101, an end cap assembly 102, and an electrode assembly 10. The housing 101 has an opening 1011, and the end cap assembly 102 is used to close the opening 1011. The end cap assembly 102 includes an end cap body 1021 and electrode terminals 1022 insulatedly connected to the end cap body 1021. The end cap body 1021 is used to cover the opening 1011. For example, the battery cell 100 can be cylindrical.

[0158] The electrode assembly 10 is disposed inside the housing 101. The electrode assembly 10 has a wound structure and includes: a main body portion 11, a first tab group 12, and a second tab group 13. The first tab group 12 and the second tab group 13 have opposite polarities and are connected to the same side of the main body portion 11 along the winding axis K of the wound structure. The first tab group 12 and the second tab group 13 are spaced apart circumferentially along the wound structure. Among them, the first tab group 12 is electrically connected to the electrode terminal 1022, and the center line of the electrode terminal 1022 is offset by a preset distance in the radial direction of the wound structure with respect to the winding axis K. The second tab group 13 is electrically connected to the end cap body 1021.

[0159] The electrode terminal 1022 can be designed as a composite electrode terminal, which includes a first terminal portion 1022A, a second terminal portion 1022B, and an insulating member 1022C. The first terminal portion 1022A and the second terminal portion 1022B are connected along the direction where the winding axis K is located. The second terminal portion 1022B is located between the first terminal portion 1022A and the electrode assembly 10. The insulating member 1022C is sleeved outside the first terminal portion 1022A and the second terminal portion 1022B.

[0160] For example, the electrode terminal 1022 is a negative terminal. The first terminal portion 1022A is made of aluminum material and is used to connect to the external circuit of the battery cell 100. The second terminal portion 1022B is made of copper material and can be designed as a disc-shaped structure. Since there is still a certain distance between the second terminal portion 1022B and the first tab group 12, the second terminal portion 1022B and the first tab group 12 are electrically connected through an adapter 103, such as by welding or other means.

[0161] The adapter 103 may include a first connection portion 1031 and a second connection portion 1032. The first connection portion 1031 is electrically connected to the first tab group 12, and the second connection portion 1032 is electrically connected to the second terminal portion 1022B. In order to increase the effective connection length between the adapter 103 and the first tab group 12, the radial dimension of the first connection portion 1031 is larger than that of the second connection portion 1032. A through hole extending along the winding axis K is provided on the first terminal portion 1022A to form a first groove 1022' on the surface of the electrode terminal 1022 away from the electrode assembly 10, and a portion of the second terminal portion 1022B corresponding to the through hole is used as a first welding portion W1 to be welded to the second connection portion 1032.

[0162] A second groove 1021' is provided on the surface of the end cap body 1021 away from the electrode assembly 10. The second groove 1021' is recessed in the direction close to the electrode assembly 10. A second welding portion W2 is formed between the bottom surface of the second groove 1021' and the surface of the end cap body 1021 close to the electrode assembly 10. The second tab group 13 is welded to the second welding portion W2. The end cap body 1021 includes a main body plate 1021A and a protruding portion 1021B. The protruding portion 1021B is connected to the side of the main body plate 1021A close to the electrode assembly 10. The second groove 1021' extends into the protruding portion 1021B. The protruding portion 1021B protrudes to abut against the second tab group 13, and the second welding portion W2 is directly welded to the second tab group 13 through the second groove 1021', without the need to provide an adapter 103.

[0163] Figures 5 to 9B The structure of the electrode assembly 10 has been described in detail above and will not be elaborated here.

[0164] In some other embodiments, as Figure 10 shown, the difference from the embodiment shown in Figure 4 is that the middle region of the second terminal portion 1022B protrudes integrally in the direction of the electrode assembly 10 and protrudes to abut against the first tab group 12. In this way, the first welding portion W1 of the second terminal portion 1022B can be directly electrically connected to the first tab group 12, eliminating the need to provide an adapter 103. The through hole of the first terminal portion 1022A and the recessed portion of the second terminal portion 1022B together form a first groove 1022', and the first welding portion W1 and the first tab group 12 can be welded through the first groove 1022'.

[0165] Secondly, the present application provides a manufacturing method of a battery cell 100. In some embodiments, as Figure 11 shown, the manufacturing method includes:

[0166] S110. Component providing step: Provide a housing 101, an end cap assembly 102, and an electrode assembly 10. Among them, the housing 101 has an opening 1011. The end cap assembly 102 includes an end cap body 1021 and electrode terminals 1022 insulatedly connected to the end cap body 1021. The center line of the electrode terminals 1022 is offset by a preset distance in the radial direction of the winding structure with respect to the winding axis K. The electrode assembly 10 is in a winding structure and includes a main body portion 11, a first tab group 12, and a second tab group 13. The first tab group 12 and the second tab group 13 have opposite polarities and are connected to the same side of the main body portion 11 along the winding axis K of the winding structure.

[0167] S120. End cap installation step: Close the opening 1011 with the end cap assembly 102, electrically connect the first tab group 12 to the electrode terminals 1022, and electrically connect the second tab group 13 to the end cap body 1021.

[0168] In this embodiment, the first tab group 12 and the second tab group 13 are led out from the same end of the main body portion 11. Only an electrical connection space needs to be reserved at one end of the electrode assembly 10, and it also eliminates the need to separately provide electrode terminals 1022 at both ends of the battery cell 100, which can effectively improve the overall energy density of the battery cell 100. When the capacity of the battery cell 100 is certain, the volume of the battery cell 100 can be reduced, making it easier to layout the battery 200 in the electrical device.

[0169] Moreover, such a battery cell 100 is provided with only one electrode terminal 1022. The first tab group 12 is electrically connected to the electrode terminal 1022, and the second tab group 13 is directly electrically connected to the end cap body 1021, which can simplify the structure and assembly process of the battery cell 100. When the area of the end cap body 1021 is small, it solves the problem that it is difficult to layout the electrode terminal 1022, the liquid injection hole, the pressure relief structure, etc. on the end cap body 1021. And because the layout space of the electrode terminal 1022 is relatively abundant, the position of the electrode terminal 1022 can be flexibly adjusted according to the position of the first tab group 12, which is also beneficial to increasing the cross-sectional area of the electrode terminal 1022 to increase the overcurrent capacity of the battery cell 100. In addition, the center line of the electrode terminals 1022 is offset by a preset distance in the radial direction of the winding structure with respect to the winding axis K, which can further leave an abundant space for arranging other components on the end cap body 1021.

[0170] Finally, the present application proposes a manufacturing device 400 for a battery cell 100. In some embodiments, as Figure 12 shown, the manufacturing device 400 includes a component providing device 410 and an end cap installing device 420.

[0171] The component providing device 410 is configured to provide a housing 101, an end cap assembly 102 and an electrode assembly 10; wherein, the housing 101 has an opening 1011, the end cap assembly 102 includes an end cap body 1021 and electrode terminals 1022 insulatedly connected to the end cap body 1021, and the center line of the electrode terminals 1022 is radially offset from the winding axis K by a preset distance in the radial direction of the winding structure; the electrode assembly 10 is in a winding structure and includes: a main body portion 11, a first tab group 12 and a second tab group 13, the first tab group 12 and the second tab group 13 have opposite polarities and are connected to the same side of the main body portion 11 along the winding axis K of the winding structure.

[0172] The end cap mounting device 420 is configured to close the opening 1011 with the end cap assembly 102, electrically connect the first tab group 12 with the electrode terminals 1022, and electrically connect the second tab group 13 with the end cap body 1021.

[0173] Although the present application has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (100) includes: A housing (101) having an opening (1011); An end cap assembly (102) for closing the opening (1011), the end cap assembly (102) includes an end cap body (1021) and an electrode terminal (1022), and the electrode terminal (1022) is insulated and connected to the end cap body (1021); And An electrode assembly (10) disposed within the housing (101), the electrode assembly (10) has a wound structure and includes: a main body portion (11), a first tab group (12), and a second tab group (13), the first tab group (12) and the second tab group (13) have opposite polarities and are connected to the same side of the main body portion (11) along the winding axis (K) of the wound structure; Wherein, the first tab group (12) is electrically connected to the electrode terminal (1022), and the center line of the electrode terminal (1022) is offset by a preset distance in the radial direction of the wound structure with respect to the winding axis (K), and the second tab group (13) is electrically connected to the end cap body (1021); The main body portion (11) has a plurality of electrode plate layers (111) along the radial direction, the first tab group (12) includes a plurality of first tabs (12') stacked, and the second tab group (13) includes a plurality of second tabs (13') stacked; in the radial direction, at least two adjacent first tabs (12') in the first tab group (12) are separated by more than one electrode plate layer (111) of the same polarity, and / or at least two adjacent second tabs (13') in the second tab group (13) are separated by more than one electrode plate layer (111) of the same polarity; The number of electrode plate layers (111) of the same polarity separated between every two adjacent first tabs (12') in the first tab group (12) is equal, and / or the number of electrode plate layers (111) of the same polarity separated between every two adjacent second tabs (13') in the second tab group (13) is equal; or, the number of electrode plate layers (111) separated between every two adjacent first tabs (12') in the first tab group (12) gradually decreases from the inside to the outside, and / or the number of electrode plate layers (111) separated between every two adjacent second tabs (13') in the second tab group (13) gradually decreases from the inside to the outside.

2. The battery cell (100) according to claim 1, wherein, The first tab group (12) and the second tab group (13) are spaced apart along the circumferential direction of the wound structure.

3. The battery cell (100) according to claim 1 or 2, wherein, A first groove (1022') is provided on the surface of the electrode terminal (1022) away from the electrode assembly (10), the first groove (1022') is recessed in the direction close to the electrode assembly (10), and a first welding portion (W1) is formed between the bottom surface of the first groove (1022') and the surface of the electrode terminal (1022) close to the electrode assembly (10), and the first tab group (12) is welded to the first welding portion (W1).

4. The battery cell (100) according to claim 1, wherein, On the surface of the end cap body (1021) away from the electrode assembly (10), there is a second groove (1021'), the second groove (1021') is recessed in the direction close to the electrode assembly (10), and a second welding part (W2) is formed between the bottom surface of the second groove (1021') and the surface of the end cap body (1021) close to the electrode assembly (10), and the second tab group (13) is welded to the second welding part (W2).

5. The battery cell (100) according to claim 4, wherein, The end cap body (1021) includes a main body plate (1021A) and a protruding part (1021B), the protruding part (1021B) is arranged on the side of the main body plate (1021A) close to the electrode assembly (10), and the second groove (1021') extends into the protruding part (1021B).

6. The battery cell (100) according to claim 1 further comprises: Adapter (103), the first tab group (12) is electrically connected to the electrode terminal (1022) through the adapter (103), and / or the second tab group (13) is electrically connected to the end cap body (1021) through the adapter (103).

7. The battery cell (100) according to claim 6, wherein, The adapter (103) includes: a first connecting part (1031) and a second connecting part (1032) connected to each other, and the dimension of the first connecting part (1031) along the radial direction is larger than the dimension of the second connecting part (1032). For the adapter (103) connected between the first tab group (12) and the electrode terminal (1022), the first connecting part (1031) is electrically connected to the first tab group (12), and the second connecting part (1032) is electrically connected to the electrode terminal (1022); and / or For the adapter (103) connected between the second tab group (13) and the end cap body (1021), the first connecting part (1031) is electrically connected to the second tab group (13), and the second connecting part (1032) is electrically connected to the end cap body (1021).

8. The battery cell (100) according to claim 1, wherein, The first tab group (12) is a negative tab group, and the second tab group (13) is a positive tab group.

9. The battery cell (100) according to claim 1, wherein, In the radial direction, the innermost first tab (12') is led out from the n1-th same-polarity tab layer (111) starting from the innermost side, n1>1; and / or the innermost second tab (13') is led out from the n2-th same-polarity tab layer (111) starting from the innermost side, n2>1.

10. The battery cell (100) according to claim 1, wherein, The first tab group (12) and the second tab group (13) are symmetrically arranged with respect to the winding axis (K).

11. The battery cell (100) according to claim 1, wherein, The housing (101) has a recess (1012) which is recessed inward as a whole in the circumferential direction relative to the outer wall of the housing (101). The housing (101) forms a bent portion (1013) at one end of the recess (1012) close to the opening (1011). The bent portion (1013) has a receiving cavity (Q). The outer end of the end cap body (1021) in the radial direction is embedded in the receiving cavity (Q). The battery cell (100) further includes a seal (104), and the seal (104) is arranged between the bent portion (1013) and the end cap body (1021).

12. A battery (200), comprising: The battery cell (100) according to any one of claims 1 to 11; And A box body (201) for accommodating the battery cell (100).

13. An electrical device, comprising the battery (200) according to claim 12, and the battery (200) is used to provide electrical energy for the electrical device.

14. A manufacturing method of a battery cell (100), comprising: Component providing step: providing a housing (101), an end cap assembly (102) and an electrode assembly (10); wherein, the housing (101) has an opening (1011), the end cap assembly (102) includes an end cap body (1021) and electrode terminals (1022) insulated and connected to the end cap body (1021); the electrode assembly (10) is in a wound structure and includes: a main body portion (11), a first tab group (12) and a second tab group (13), the first tab group (12) and the second tab group (13) have opposite polarities and are connected to the same side of the main body portion (11) along the winding axis (K) of the wound structure, and the center line of the electrode terminal (1022) is offset by a preset distance in the radial direction of the wound structure relative to the winding axis (K); End cap mounting step: closing the opening (1011) with the end cap assembly (102), electrically connecting the first tab group (12) to the electrode terminal (1022), and electrically connecting the second tab group (13) to the end cap body (1021); The main body portion (11) has a plurality of electrode plate layers (111) in the radial direction. The first tab group (12) includes a plurality of first tabs (12') arranged in a stacked manner. The second tab group (13) includes a plurality of second tabs (13') arranged in a stacked manner; in the radial direction, at least two adjacent first tabs (12') in the first tab group (12) are separated by more than one electrode plate layer (111) of the same polarity, and / or at least two adjacent second tabs (13') in the second tab group (13) are separated by more than one electrode plate layer (111) of the same polarity; The number of the same-polarity electrode sheet layers (111) spaced between every two adjacent first tab groups (12) in the first tab group (12) is equal, and / or the number of the same-polarity electrode sheet layers (111) spaced between every two adjacent second tab groups (13) in the second tab group (13) is equal; or, the number of the electrode sheet layers (111) spaced between every two adjacent first tabs (12') in the first tab group (12) gradually decreases from the inside to the outside, and / or the number of the electrode sheet layers (111) spaced between every two adjacent second tabs (13') in the second tab group (13) gradually decreases from the inside to the outside.

15. A manufacturing apparatus (400) for a battery cell (100), comprising: a component providing device (410) configured to provide a housing (101), an end cap assembly (102), and an electrode assembly (10); wherein, the housing (101) has an opening (1011), the end cap assembly (102) includes an end cap body (1021) and an electrode terminal (1022) insulatedly connected to the end cap body (1021); the electrode assembly (10) has a wound structure and includes: a main body part (11), a first tab group (12), and a second tab group (13), the first tab group (12) and the second tab group (13) have opposite polarities and are connected to the same side of the main body part (11) along the winding axis (K) of the wound structure, and the center line of the electrode terminal (1022) is offset by a preset distance in the radial direction of the wound structure with respect to the winding axis (K); and an end cap mounting device (420) configured to close the opening (1011) with the end cap assembly (102), electrically connect the first tab group (12) to the electrode terminal (1022), and electrically connect the second tab group (13) to the end cap body (1021); the main body part (11) has a plurality of electrode sheet layers (111) in the radial direction, the first tab group (12) includes a plurality of first tabs (12') stacked, the second tab group (13) includes a plurality of second tabs (13') stacked; in the radial direction, at least one more same-polarity electrode sheet layer (111) is spaced between at least two adjacent first tabs (12') in the first tab group (12), and / or at least one more same-polarity electrode sheet layer (111) is spaced between at least two adjacent second tabs (13') in the second tab group (13); The number of the same-polarity electrode sheet layers (111) spaced between every two adjacent first tabs (12') in the first tab group (12) is equal, and / or the number of the same-polarity electrode sheet layers (111) spaced between every two adjacent second tabs (13') in the second tab group (13) is equal; or, the number of the electrode sheet layers (111) spaced between every two adjacent first tabs (12') in the first tab group (12) gradually decreases from the inside to the outside, and / or the number of the electrode sheet layers (111) spaced between every two adjacent second tabs (13') in the second tab group (13) gradually decreases from the inside to the outside.

Images