Battery cell, battery, and electric device

Abstract

The application provides a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. The battery monomer comprises a first pole piece, a diaphragm and a plurality of second pole pieces. The first pole piece is provided with a plurality of structure weakening zones extending along the width direction of the first pole piece; the diaphragm covers the surfaces of the opposite sides of the first pole piece; and the plurality of second pole pieces are alternately arranged on the diaphragms of the opposite sides of the first pole piece, wherein, along the length direction of the first pole piece, every two adjacent second pole pieces are located on different sides of the first pole piece, and there is a corresponding structure weakening zone between every two adjacent second pole pieces; wherein the first pole piece is folded at the plurality of structure weakening zones, so that the first pole piece and the plurality of second pole pieces are alternately stacked with each other.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

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

[0003] However, the performance of individual battery cells is still difficult to achieve optimal performance. Therefore, how to improve the performance of individual battery cells is an urgent problem to be solved in battery technology. Summary of the Invention

[0004] This application aims to at least address one of the technical problems existing in the background art. Therefore, one object of this application is to provide a battery cell, a battery, and an electrical device to improve the performance of the battery cell.

[0005] An embodiment of the first aspect of this application provides a battery cell, which includes a first electrode, a separator, and a plurality of second electrodes. The first electrode has a plurality of structural weakening regions extending along its width direction; the separator covers the surfaces of opposite sides of the first electrode; the plurality of second electrodes are alternately disposed on the separator on opposite sides of the first electrode, wherein, along the length direction of the first electrode, every two adjacent second electrodes are located on different sides of the first electrode, and there is a corresponding structural weakening region between every two adjacent second electrodes; wherein the first electrode is folded at the plurality of structural weakening regions, such that the first electrode and the plurality of second electrodes are alternately stacked.

[0006] In the technical solution of this application embodiment, a plurality of structural weakening regions extending along the width direction of the first electrode are provided on the first electrode. Since the mechanical strength of the plurality of structural weakening regions is less than that of the remaining areas of the first electrode, by providing a plurality of structural weakening regions extending along the width direction of the first electrode, the first electrode can be bent more easily and can be folded accurately at a predetermined position, reducing the misalignment between the first electrode and the second electrode and improving the flatness of the first electrode after folding. Furthermore, when the multiple segments of the first electrode and the multiple second electrodes are stacked alternately, the segments of every two adjacent first electrodes are connected by structural weakening regions, every two adjacent second electrodes are located on different sides of the first electrode, and there is a corresponding structural weakening region between every two adjacent second electrodes, reducing the gap between the first electrode and the second electrode, reducing the lithium plating problem of the battery cell, thereby improving the performance of the battery cell.

[0007] In some embodiments, the structural weakening region includes a groove extending along the width direction of the first electrode. The groove extending along the width direction of the first electrode provides superior guidance for bending the first electrode, and also improves the accuracy of the folding position, reducing the misalignment between adjacent electrode layers in the battery cell, thereby giving the battery cell better performance.

[0008] In some embodiments, the structural weakening region includes two grooves extending along the width direction of the first electrode, the two grooves being spaced apart from each other along the length direction of the first electrode. The structural weakening region includes two grooves extending along the width direction of the first electrode, the two grooves being spaced apart from each other along the length direction of the first electrode. This allows the first electrode to be folded along the two grooves, making the first electrode easier to fold, improving the accuracy of the folding position, and allowing the segments of the first electrode to be aligned with each other, reducing the misalignment between the first electrode and the second electrode, thereby further improving the performance of the battery cell.

[0009] In some embodiments, the distance between the two grooves is greater than or equal to the thickness of the corresponding second electrode. The first electrode is folded at multiple structural weakening regions, and the distance between the resulting bends is greater than or equal to the thickness of the second electrode. This allows the second electrode to be prevented from being squeezed by the first electrode when multiple segments of the first electrode and multiple second electrodes are stacked alternately. It also reduces the gap between the first and second electrodes at the bends, reducing lithium plating problems in the battery cell and thus improving the performance of the battery cell.

[0010] In some embodiments, the length of each groove is less than or equal to the width of the first electrode. The length of each groove being less than or equal to the width of the first electrode limits the maximum length of the groove. Since the length of the groove will not exceed the width of the first electrode, the mechanical strength of the structurally weakened area can be maintained at a certain level, thereby reducing the probability of the first electrode breaking during folding and improving the yield rate of battery cell production.

[0011] In some embodiments, the structural weakening region also includes a through hole extending through the thickness of the first electrode. Since the first electrode is relatively thin, the depth of the through hole does not need to be precisely controlled, which reduces the requirements for processing accuracy. Moreover, the through hole can significantly weaken the strength of the first electrode, making it easier to fold.

[0012] In some embodiments, the number of through holes N satisfies: N≥2. By providing multiple through holes, the mechanical strength of the first electrode can be weakened, while the weakened area of ​​the first electrode structure can maintain a certain mechanical strength, thereby reducing the possibility of the first electrode breaking when folded.

[0013] In some embodiments, multiple structural weakening regions are equidistantly spaced from each other along the length of the first electrode. This equidistant spacing allows the weakening regions to be located at bends, weakening the strength at the bends and making the first electrode easier to bend. This enables accurate folding at predetermined positions, reduces misalignment of the multilayer electrode, improves the flatness of the folded first electrode, and ultimately enhances the performance of the battery cell.

[0014] In some embodiments, the first electrode is an anode electrode and the second electrode is a cathode electrode. Setting the outermost layer of the battery cell as an anode electrode reduces the number of layers in the folded negative electrode and allows for full utilization of the cathode active material in the cathode electrode.

[0015] An embodiment of the second aspect of this application provides a method for manufacturing a battery cell, comprising: forming a plurality of structurally weakened regions on a first electrode sheet, the plurality of structurally weakened regions extending along the width direction of the first electrode sheet; covering the surfaces of opposite sides of the first electrode sheet with a separator; alternately disposing a plurality of second electrodes on the separators on opposite sides of the first electrode sheet, wherein, along the length direction of the first electrode sheet, every two adjacent second electrodes are located on different sides of the first electrode sheet, and there is a corresponding structurally weakened region between every two adjacent second electrodes; folding the first electrode sheet at the plurality of structurally weakened regions, such that the first electrode sheet and the plurality of second electrodes are alternately stacked on top of each other.

[0016] In the technical solution of this application embodiment, by forming multiple structural weakening regions extending along the width direction of the first electrode, the first electrode can be bent more easily and folded accurately at a predetermined position, reducing the misalignment between the first and second electrodes and improving the flatness of the folded first electrode. Furthermore, when multiple segments of the first electrode and multiple second electrodes are stacked alternately, the segments of every two adjacent first electrodes are connected by structural weakening regions, every two adjacent second electrodes are located on different sides of the first electrode, and there is a corresponding structural weakening region between every two adjacent second electrodes. This reduces the gap between the first and second electrodes, reduces lithium plating problems, and thus improves the performance of the battery cell.

[0017] An embodiment of the third aspect of this application provides a battery comprising the battery cell described in the above embodiments.

[0018] An embodiment of the fourth aspect of this application provides an electrical device that includes the battery described in the above embodiments, the battery being used to provide electrical energy.

[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0020] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0021] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0022] Figure 2 This is an exploded structural diagram of a battery according to some embodiments of this application;

[0023] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0024] Figure 4 This is a schematic diagram of the first electrode sheet in an unfolded state according to some embodiments of this application;

[0025] Figure 5 This is a schematic diagram of the structure of a battery cell formed by folding according to some embodiments of this application;

[0026] Figure 6 for Figure 4 AA section view in the middle;

[0027] Figure 7 Flowcharts illustrating methods for producing individual battery cells provided in some embodiments of this application;

[0028] Figure 8 This is a schematic diagram of the first electrode and the diaphragm in some embodiments of this application;

[0029] Figure 9 This is a schematic diagram of the composite of a first electrode, a second electrode, and a diaphragm in some embodiments of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1000, vehicles;

[0032] 100. Battery; 200. Controller; 300. Motor;

[0033] 10. Box body; 11. First part; 12. Second part;

[0034] 20. Battery cell; 21. End cap; 21a. Electrode terminal; 22. Housing; 23. Cell assembly; 23a. Tab;

[0035] 231. First electrode; 232. Second electrode; 233. Diaphragm; 234. Structural weakening zone; 235. Groove; 236. Through hole; 237. Roller. Detailed Implementation

[0036] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0038] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0039] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0040] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0041] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0042] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0043] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0044] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0045] A battery typically consists of one or more individual cells, which are the smallest units that make up a battery. These individual cells can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple individual cells are connected in both series and parallel configurations.

[0046] Furthermore, a single battery cell is mainly formed by winding or stacking cathode and anode electrodes, and a separator is usually provided between the cathode and anode electrodes. Because stacked battery cells have advantages over wound battery cells in terms of higher rate capability and higher energy density, and because stacked battery cells can be manufactured into various irregularly shaped batteries according to different needs, stacked battery cells are widely used in the industry for battery production.

[0047] Currently, in the production process of stacked battery cells, continuous electrode sheets can be repeatedly folded to form stacked battery cells. However, stacked battery cells are difficult to achieve optimal performance. One important factor is that during the folding process, it is difficult to fold the continuous electrode sheets accurately at the predetermined positions, resulting in a large misalignment of the multiple electrode layers and poor flatness after folding.

[0048] To address this, it was considered to set grooves at the folding position to guide the continuous electrode sheet to fold at the predetermined position. However, generally there is only one groove, and the continuous electrode sheet is still difficult to fold normally. At the corner of the continuous electrode sheet folding, there will be non-overlapping parts between the anode and cathode electrodes. At the same time, the electrodes are also prone to skew during the folding process, which means that some of the lithium ions electrolyzed from the cathode electrode cannot reach the coating area of ​​the active material of the anode electrode directly opposite it, resulting in lithium plating. Therefore, the technical effect of improving the performance of the battery cell is not obvious.

[0049] Based on the problems analyzed above, this application proposes a battery cell comprising a first electrode with multiple structural weakening regions extending along its width and spaced apart along its length to divide it into segments. The mechanical strength of each weakening region is less than that of the remaining areas of the first electrode. A separator covers the surfaces of opposite sides of the first electrode. The first electrode also includes multiple second electrodes alternately disposed on the separators on opposite sides of the first electrode. Along the length of the first electrode, every two adjacent second electrodes are located on different sides of the first electrode, and a corresponding structural weakening region exists between every two adjacent second electrodes. The first electrode is folded at the multiple structural weakening regions, causing the segments of the first electrode and the multiple second electrodes to be stacked alternately. This allows for precise folding at predetermined positions, reducing misalignment in the multi-layer electrode structure, improving the flatness of the folded first electrode, and reducing the gap between the first and second electrodes, thus reducing lithium plating and improving the performance of the battery cell.

[0050] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and batteries disclosed in this application. This helps to reduce the misalignment of the multi-layered electrodes, improve the flatness of the first electrode after folding, and thus enhance the performance of the battery cells.

[0051] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0052] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0053] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0054] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0055] Please refer to Figure 2 , Figure 2This is an exploded structural diagram of a battery provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0056] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0057] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0058] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application. The battery cell 20 refers to the smallest unit that makes up the battery. For example... Figure 3 The battery cell 20 includes an end cap 21, a housing 22, a cell assembly 23, and other functional components.

[0059] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 21 can be adapted to the shape of housing 22 to fit it. Optionally, end cap 21 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 21 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved safety performance. Functional components such as electrode terminals 21a can be provided on end cap 21. Electrode terminals 21a can be used for electrical connection with cell assembly 23 to output or input electrical energy to battery cell 20. In some embodiments, end cap 21 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 20 reaches a threshold. The material of end cap 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, an insulating element may be provided on the inner side of the end cap 21. The insulating element can be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0060] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the cell assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the cell assembly 23. The housing 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0061] The cell assembly 23 is the component in the battery cell 20 where the electrochemical reaction occurs. The casing 22 may contain one or more cell assemblies 23. The cell assembly 23 is mainly formed by winding or stacking positive and negative electrode plates, and typically a separator is provided between the positive and negative electrode plates. The portions of the positive and negative electrode plates containing active material constitute the main body of the cell assembly, while the portions of the positive and negative electrode plates without active material each constitute a tab 23a. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 23a connect to the electrode terminals to form a current loop.

[0062] This application provides a battery cell 20. Figure 4 This is a schematic diagram of the first electrode 231 in an unfolded state according to some embodiments of this application. Figure 5 This is a schematic diagram of the structure of a folded battery cell 20 according to some embodiments of this application, such as... Figure 4 and Figure 5 As shown, the battery cell 20 includes a first electrode 231, a separator 233, and a plurality of second electrodes 232. The first electrode 231 has a plurality of structural weakening regions 234 extending along the width direction W of the first electrode 231; the separator 233 covers opposite sides of the first electrode 231; the plurality of second electrodes 232 are alternately disposed on the separator 233 on opposite sides of the first electrode 231, wherein, along the length direction L of the first electrode 231, every two adjacent second electrodes 232 are located on different sides of the first electrode 231, and there is a corresponding structural weakening region 234 between every two adjacent second electrodes 232; wherein the first electrode 231 is folded at the plurality of structural weakening regions 234, such that the first electrode 231 and the plurality of second electrodes 232 are alternately stacked.

[0063] In this embodiment, the battery cell 20 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this embodiment does not limit it.

[0064] In this embodiment, the first electrode 231 and the second electrode 232 have opposite polarities, and multiple segments of the first electrode 231 and the second electrode 232 are stacked alternately. Specifically, the first electrode 231 can be a cathode electrode and the second electrode 232 can be an anode electrode; or, the first electrode 231 can be an anode electrode and the second electrode 232 can be a cathode electrode.

[0065] Figure 4This is a schematic diagram of the first electrode 231 in an unfolded state according to some embodiments of this application. L represents the length direction of the first electrode 231, and W represents the width direction of the first electrode 231. The first electrode 231 has a plurality of structural weakening regions 234 extending along the width direction W. The structural weakening regions 234 can be provided by including grooves 235 on the first electrode 231, or by including through holes 236 on the first electrode 231. The strength of the structural weakening regions 234 is less than the mechanical strength of the remaining areas of the first electrode 231. For example, the first electrode 231 may include a current collector and an active material layer. The active material layer is disposed on the surface of the current collector perpendicular to the thickness direction, and the active material layer may be disposed on both sides of the current collector. The structural weakening regions 234 can be provided by removing the active material from the surface of the active material layer to weaken the mechanical strength of the first electrode 231.

[0066] A separator 233 covers the opposite sides of the first electrode 231, which insulates the first electrode 231 and the second electrode 232, improving the performance and safety of the battery cell 20. This application does not impose any particular limitation on the type of separator 233; any known porous separator 233 with good chemical and mechanical stability can be selected. As an example, the main material of the separator 233 can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator 233 can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator 233 is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0067] Figure 5 This is a schematic diagram of the structure of a folded battery cell 20 according to some embodiments of this application. The battery cell 20 includes a first electrode 231, a separator 233, and a plurality of second electrodes 232. The first electrode 231 and the separator 233 covering opposite sides of the first electrode 231 are folded in a plurality of structural weakening regions 234, such that the plurality of segments of the first electrode 231 and the plurality of second electrodes 232 are stacked alternately. The structural weakening regions 234 are located at the bends. Every two adjacent segments of the first electrode 231 are connected through the structural weakening regions 234. Every two adjacent second electrodes 232 are located on different sides of the first electrode 231, and there is a corresponding structural weakening region 234 between every two adjacent second electrodes 232.

[0068] In the structural weakening region 234 of the continuous electrode fold, the first electrode 231 of the structural weakening region 234 wraps around the second electrode 232, and the first electrode 231 and the second electrode 232 overlap. Thus, during the reaction of the battery cell 20, the lithium ions electrolyzed by the cathode electrode can all reach the coating area of ​​the active material of the anode electrode that is directly opposite it, and the active material at the fold position is not easy to fall off due to folding, and the first electrode 231 is not easy to break due to folding.

[0069] In this embodiment, a plurality of structural weakening regions 234 extending along the width direction W of the first electrode 231 are provided on the first electrode 231. Since the mechanical strength of the plurality of structural weakening regions 234 is less than that of the other areas of the first electrode 231, by providing a plurality of structural weakening regions 234 extending along the width direction W of the first electrode 231 on the first electrode 231, the first electrode 231 can be bent more easily and can be folded accurately at a predetermined position, reducing the misalignment between the first electrode 231 and the second electrode 232 and improving the flatness of the first electrode 231 after folding. Furthermore, when multiple segments of the first electrode 231 and multiple second electrodes 232 are stacked alternately, the segments of every two adjacent first electrodes 231 are connected by a structural weakening region 234, and every two adjacent second electrodes 232 are located on different sides of the first electrode 231. There is also a corresponding structural weakening region 234 between every two adjacent second electrodes 232, which reduces the gap between the first electrode 231 and the second electrode 232, reduces the lithium plating problem of the battery cell 20, and thus improves the performance of the battery cell 20.

[0070] According to some embodiments of this application, the structural weakening region 234 includes a groove 235 extending along the width direction W of the first electrode 231.

[0071] In this embodiment, the groove 235 extends along the width direction W of the first electrode 231. The groove 235 can be formed by means of metal cutting tools, laser cutting tools, liquid etching, etc. The cross-section of the groove 235 can be set as rectangular, trapezoidal, or triangular, etc. For example, the first electrode 231 may include a current collector and an active material layer. The active material layer is disposed in the current collector. The groove 235 extending along the width direction W of the first electrode 231 can be formed by removing the active material from the active material layer. The depth of the groove 235 does not exceed the thickness of the first electrode 231.

[0072] Optionally, Figure 6 for Figure 4In the AA cross-sectional view, the cross-section of the groove 235 can be triangular, and the number of grooves 235 can be multiple. After the first electrode 231 is folded in the structural weakening region 234, the groove 235 is located inside the bend. When the groove 235 is located inside the bend, even if the radius of curvature inside the bend is small, or the width of the groove 235 along the extension direction is small, it is not easy for two adjacent segments of the first electrode 231 to interfere with each other, so that the first electrode 231 can be folded smoothly and the possibility of powder shedding is reduced.

[0073] In this embodiment, the structural weakening region 234 includes a groove 235 extending along the width direction W of the first electrode 231, which has a better effect of guiding the bending of the first electrode 231. Moreover, the groove 235 can improve the accuracy of the folding position and reduce the misalignment of adjacent two electrode layers in the battery cell 20, thereby giving the battery cell 20 good performance.

[0074] According to some embodiments of this application, the structural weakening region 234 includes two grooves 235 extending along the width direction W of the first electrode 231, and the two grooves 235 are spaced apart from each other along the length direction L of the first electrode 231.

[0075] In this embodiment, the structural weakening region 234 includes two grooves 235 extending along the width direction W of the first electrode 231. The two grooves 235 are spaced apart from each other along the length direction L of the first electrode 231, which allows the first electrode 231 to be folded along the two grooves 235, making the first electrode 231 easier to fold, improving the accuracy of the folding position, and aligning the segments of the first electrode 231 with each other, reducing the misalignment between the first electrode 231 and the second electrode 232, thereby further improving the performance of the battery cell 20.

[0076] According to some embodiments of this application, the distance between the two grooves 235 is greater than or equal to the thickness of the corresponding second electrode 232.

[0077] In this embodiment, the spacing between the two grooves 235 is greater than or equal to the thickness of the corresponding second electrode 232. This allows the spacing of the structural weakening regions 234 of the first electrode 231 along the length L of the first electrode 231 to be greater than or equal to the thickness of the corresponding second electrode 232. The first electrode 231 is folded at multiple structural weakening regions 234, and the spacing at the resulting bends is greater than or equal to the thickness of the second electrode 232. This ensures that when multiple segments of the first electrode 231 and multiple second electrodes 232 are stacked alternately, the second electrode 232 is not squeezed by the first electrode 231. At the same time, it can also reduce the gap between the first electrode 231 and the second electrode 232 at the bends, reducing the lithium plating problem of the battery cell 20 and thus improving the performance of the battery cell 20.

[0078] According to some embodiments of this application, the length of each groove 235 is less than or equal to the width of the first electrode 231.

[0079] In this embodiment of the application, the length of each groove 235 is less than or equal to the width of the first electrode 231, which limits the maximum length of the groove 235. Since the length of the groove 235 will not exceed the width of the first electrode 231, the mechanical strength of the structural weakening area 234 can be maintained at a certain level, thereby reducing the probability of the first electrode 231 breaking during the folding process and improving the yield of the battery cell 20.

[0080] According to some embodiments of this application, the structural weakening region 234 also includes a through hole 236 that extends through the thickness of the first electrode 231.

[0081] In this embodiment, the through hole 236 can be a circular hole, a rectangular hole, an elliptical hole, or a diamond-shaped hole, etc. By providing the through hole 236, the strength of the bend can also be weakened, serving the same function as the groove 235. Simultaneously, the through hole 236 can also serve a positioning function. The number of through holes 236 can be one or more.

[0082] For example, such as Figure 4 As shown, the through hole 236 can be located in the middle of the two grooves 235.

[0083] In some embodiments, the structural weakening region 234 of the first electrode 231 may include both a groove 235 and a through hole 236. The groove 235 and the through hole 236 can work together to weaken the mechanical strength of the structural weakening region 234 of the first electrode 231. Since the structural weakening region 234 of the first electrode 231 includes the through hole 236, the depth of the groove 235 can be appropriately reduced when the same mechanical strength is required. This is beneficial to improving the stress situation of the first electrode 231 in the structural weakening region 234 when folded, and reducing the risk of breakage while ensuring that the first electrode 231 is easy to bend.

[0084] In this embodiment, since the first electrode 231 is thin, the depth of the through hole 236 does not need to be precisely controlled, which reduces the requirements for processing accuracy. Moreover, the through hole 236 can significantly weaken the strength of the first electrode 231, making it easy to fold.

[0085] According to some embodiments of this application, the number N of through holes 236 satisfies: N≥2.

[0086] In this embodiment, the through holes 236 can be spaced apart along the width direction W of the first electrode 231. By providing multiple through holes 236, the mechanical strength of the first electrode 231 can be weakened, while the structural weakening area 234 of the first electrode 231 can maintain a certain mechanical strength, thereby reducing the possibility of the first electrode 231 breaking when folded.

[0087] According to some embodiments of this application, a plurality of structural weakening regions 234 are equidistant from each other along the length direction L of the first electrode 231.

[0088] In the embodiments of this application, in Figure 4 In the schematic diagram of the first electrode 231 in its unfolded state, multiple structural weakening regions 234 are spaced apart along the length L of the first electrode 231, each located at the point to be folded. The multiple structural weakening regions 234 are equidistant from each other along the length L of the first electrode 231, exhibiting high parallelism. Furthermore, the folded battery cell 20 has neat edges along the stacking direction. During the folding process, an automatic tapping mechanism assists in the folding, facilitating proper folding.

[0089] In this embodiment, multiple structural weakening regions 234 are equidistant from each other along the length direction L of the first electrode 231. By setting an appropriate spacing distance, the structural weakening regions 234 can be located at the bending point to weaken the strength at the bending point, making the first electrode 231 easier to bend and fold accurately at a predetermined position. This reduces the misalignment of the multilayer electrode and improves the flatness of the first electrode 231 after folding, thereby improving the performance of the battery cell 20.

[0090] According to some embodiments of this application, the first electrode 231 is an anode electrode and the second electrode 232 is a cathode electrode.

[0091] In this embodiment, after the first electrode 231 is folded, it is located on the outermost side in the stacking direction. Generally, the cathode active material in the cathode electrode is a ternary material, lithium manganese oxide, or lithium iron phosphate, etc., and the anode active material in the anode electrode is generally graphite or silicon. Since the cathode active material is more expensive than the anode active material, setting the outermost layer of the battery cell 20 as the anode electrode can reduce the number of layers of the negative electrode after folding and make full use of the cathode active material of the cathode electrode.

[0092] According to some embodiments of this application, a method for producing a single battery cell is provided. Figure 7 A flowchart illustrating a method for manufacturing a single battery cell according to some embodiments of this application. See also... Figure 7 The method includes:

[0093] Step S710: Multiple structural weakening regions are formed on the first electrode, and the multiple structural weakening regions extend along the width direction of the first electrode.

[0094] Step S720: Cover the surfaces of the opposite sides of the first electrode with a diaphragm.

[0095] Step S730: Multiple second electrodes are alternately disposed on the diaphragm on opposite sides of the first electrode, wherein, along the length direction of the first electrode, every two adjacent second electrodes are located on different sides of the first electrode, and there is a corresponding structural weakening region between every two adjacent second electrodes.

[0096] Step S740: Fold the first electrode at multiple structural weakening regions, so that the first electrode and multiple second electrodes are stacked alternately.

[0097] In this embodiment of the application, the battery cell 20 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this embodiment of the application is not limited to this.

[0098] In this embodiment, the first electrode 231 and the second electrode 232 have opposite polarities, and multiple segments of the first electrode 231 and the second electrode 232 are stacked alternately. Specifically, the first electrode 231 can be a cathode electrode and the second electrode 232 can be an anode electrode; or, the first electrode 231 can be an anode electrode and the second electrode 232 can be a cathode electrode.

[0099] In this embodiment, a plurality of structural weakening regions 234 extending along the width direction W of the first electrode 231 are formed on the first electrode 231. The structural weakening regions 234 can be formed by providing grooves 235 on the first electrode 231, or by providing through holes 236 on the first electrode 231. The strength of the structural weakening regions 234 is less than the mechanical strength of the remaining areas of the first electrode 231. For example, the first electrode 231 may include a current collector and an active material layer. The active material layer is disposed on the surface of the current collector perpendicular to its thickness direction, and may be disposed on both sides of the current collector. The structural weakening regions 234 can be formed by removing the active material from the surface of the active material layer to weaken the mechanical strength of the first electrode 231.

[0100] In this embodiment, before forming the battery cell 20, the first electrode 231 and two separators 233 are stacked together to form a continuous, bendable composite electrode. The first electrode 231 and separators 233 are alternately arranged, and separators 233 are provided on both sides of the first electrode 231 to provide insulation. Adhesive layers can be provided on both sides of the separator 233, for example, the adhesive layer is a PCS layer (Polyvinylidene fluoride coated separator). During the process of heating and bonding and applying pressure to the first electrode 231 and separator 233, many particles in the PCS layer that are distributed in a dotted pattern are flattened to generate adhesion to the first electrode 231.

[0101] In one process method Figure 8 This is a schematic diagram of the composite of the first electrode 231 and the diaphragm 233 in some embodiments of this application, as shown below. Figure 8 As shown, a diaphragm 233 is covered on the surfaces of opposite sides of the first electrode 231, and pressure is applied by a roller 237 to attach the diaphragm 233 to the first electrode 231 through the PCS layer. Figure 9 This is a schematic diagram of the composite of the first electrode 231, the second electrode 232, and the diaphragm 233 in some embodiments of this application, as shown below. Figure 9 As shown, along the length direction L of the first electrode 231, a plurality of second electrodes 232 are alternately disposed on the diaphragm 233 on opposite sides of the first electrode 231. Each pair of adjacent second electrodes 232 are located on different sides of the first electrode 231, and there is a corresponding structural weakening region 234 between each pair of adjacent second electrodes 232. Pressure is applied by rollers 237 to attach the second electrodes 232 to the diaphragm 233.

[0102] In addition, they can be laminated by cold pressing, electrophoresis or bonding.

[0103] In this embodiment, the first electrode 231 and the diaphragm 233 covering the opposite sides of the first electrode 231 are folded in multiple structural weakening regions 234, such that multiple segments of the first electrode 231 and multiple second electrodes 232 are stacked alternately. The structural weakening regions 234 are located at the bends. Every two adjacent segments of the first electrode 231 are connected through the structural weakening regions 234. Every two adjacent second electrodes 232 are located on different sides of the first electrode 231, and there is a corresponding structural weakening region 234 between every two adjacent second electrodes 232.

[0104] In the structural weakening region 234 of the continuous electrode fold, the first electrode 231 of the structural weakening region 234 wraps around the second electrode 232, and the first electrode 231 and the second electrode 232 overlap. Thus, during the reaction of the battery cell 20, the lithium ions electrolyzed by the cathode electrode can all reach the coating area of ​​the active material of the anode electrode that is directly opposite it, and the active material at the fold position is not easy to fall off due to folding, and the first electrode 231 is not easy to break due to folding.

[0105] In this embodiment, by forming multiple structural weakening regions 234 extending along the width direction W of the first electrode 231 on the first electrode 231, the first electrode 231 can be bent more easily and folded accurately at a predetermined position, reducing the misalignment between the first electrode 231 and the second electrode 232 and improving the flatness of the first electrode 231 after folding. Furthermore, when multiple segments of the first electrode 231 and multiple second electrodes 232 are stacked alternately, the segments of every two adjacent first electrode 231 are connected by the structural weakening regions 234, every two adjacent second electrodes 232 are located on different sides of the first electrode 231, and there is a corresponding structural weakening region 234 between every two adjacent second electrodes 232. This reduces the gap between the first electrode 231 and the second electrode 232, reduces lithium plating problems, and thus improves the performance of the battery cell 20.

[0106] This application provides a battery comprising a battery cell 20 in any embodiment.

[0107] In this application embodiment, the battery can be applied to, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0108] By employing the battery cell 20 in the embodiments of this application, battery reliability can be improved.

[0109] This application also provides an electrical device, which includes a battery in any embodiment, the battery being used to provide electrical energy.

[0110] In this embodiment of the application, the electrical device can be, but is not limited to, a mobile phone, tablet, laptop, electric toy, power tool, electric vehicle, electric car, ship, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0111] By employing the battery in the embodiments of this application, the reliability of the power-consuming device is improved.

[0112] The technical solution of this application will be further described below through a specific embodiment, such as... Figures 1 to 9 As shown,

[0113] The battery cell 20 includes a first electrode 231, a separator 233, and a plurality of second electrodes 232. The first electrode 231 has a plurality of structural weakening regions 234 extending along the width direction W of the first electrode 231. The separator 233 covers opposite sides of the first electrode 231. The plurality of second electrodes 232 are alternately disposed on the separator 233 on opposite sides of the first electrode 231. Along the length direction L of the first electrode 231, every two adjacent second electrodes 232 are located on different sides of the first electrode 231, and there is a corresponding structural weakening region 234 between every two adjacent second electrodes 232. The first electrode 231 is folded at the plurality of structural weakening regions 234, such that the first electrode 231 and the plurality of second electrodes 232 are alternately stacked. The first electrode 231 is the anode electrode, and the second electrodes 232 are the cathode electrodes.

[0114] The structural weakening region 234 includes two grooves 235 extending along the width direction W of the first electrode 231, and the two grooves 235 are spaced apart from each other along the length direction L of the first electrode 231. The distance between the two grooves 235 is greater than or equal to the thickness of the corresponding second electrode 232. The length of each groove 235 is less than or equal to the width of the first electrode 231.

[0115] The structural weakening region 234 also includes through holes 236 that penetrate the thickness of the first electrode 231. The number N of through holes 236 satisfies: N≥2.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (20), characterized in that, include: The first electrode (231) has a plurality of structural weakening regions (234) extending along the width direction of the first electrode (231). A diaphragm (233) covers the surfaces of opposite sides of the first electrode (231); and Multiple second electrodes (232) are alternately disposed on the diaphragm (233) on opposite sides of the first electrode (231), wherein, along the length direction of the first electrode (231), every two adjacent second electrodes (232) are located on different sides of the first electrode (231), and there is a corresponding structural weakening region (234) between every two adjacent second electrodes (232). The structural weakening region (234) includes two grooves (235) extending along the width direction of the first electrode (231), the two grooves (235) being spaced apart from each other along the length direction of the first electrode (231), the first electrode (231) being folded at the plurality of structural weakening regions (234), such that the first electrode (231) and the plurality of second electrodes (232) are alternately stacked on each other; The distance between the two grooves (235) is greater than or equal to the thickness of the corresponding second electrode (232).

2. The battery cell (20) according to claim 1, characterized in that, The length of each groove (235) is less than or equal to the width of the first electrode (231).

3. The battery cell (20) according to claim 1 or 2, characterized in that, The structural weakening region (234) also includes a through hole (236) that extends through the thickness of the first electrode (231).

4. The battery cell (20) according to claim 3, characterized in that, The number N of the through holes (236) satisfies: N≥2.

5. The battery cell (20) according to claim 1 or 2, characterized in that, The plurality of structural weakening regions (234) are spaced apart from each other at equal intervals along the length direction of the first electrode (231).

6. The battery cell (20) according to claim 1 or 2, characterized in that, The first electrode (231) is the anode electrode, and the second electrode (232) is the cathode electrode.

7. A method for producing a single battery cell, characterized in that, The method includes: Multiple structural weakening regions are formed on the first electrode, and the multiple structural weakening regions extend along the width direction of the first electrode. A diaphragm is covered on the surfaces of the opposite sides of the first electrode; Multiple second electrodes are alternately disposed on the diaphragm on opposite sides of the first electrode. Along the length direction of the first electrode, every two adjacent second electrodes are located on different sides of the first electrode, and there is a corresponding structural weakening region between every two adjacent second electrodes. The structural weakening region includes two grooves extending along the width direction of the first electrode, and the two grooves are spaced apart from each other along the length direction of the first electrode. The first electrode is folded at the plurality of structurally weakened regions, such that the first electrode and the plurality of second electrodes are stacked alternately on top of each other; The distance between the two grooves (235) is greater than or equal to the thickness of the corresponding second electrode (232).

8. A battery, characterized in that, Includes the battery cell (20) as described in any one of claims 1-6.

9. An electrical device, characterized in that, The electrical device includes the battery as described in claim 8, the battery being used to provide electrical energy.

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