Battery cell, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell assembly, a battery module and a battery module, the electrode assembly is arranged in the shell assembly and comprises a first pole piece, a second pole piece and an isolating membrane, the isolating membrane is arranged between the first pole piece and the second pole piece, the electrode assembly comprises a winding axial direction, and the electrode assembly is of a roll-core-shaped structure wound around the winding axial direction and comprises a plurality of winding layers perpendicular to the winding axial direction; the winding layer comprises a first pole piece, an isolating membrane and a second pole piece which are stacked; and the buffer piece is arranged in the at least one winding layer and is positioned between the isolating membrane and the first pole piece or between the isolating membrane and the second pole piece. According to the battery monomer, the buffer piece can play a role in buffering between the outer-layer pole piece and the inner-layer pole piece of the electrode assembly, so that the stretching acting force on the outer-layer pole piece is reduced, the probability of breakage of the outer-layer pole piece is reduced, and the reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] New energy vehicles have experienced rapid growth in recent years. Within the electric vehicle sector, power batteries, as the power source, play an irreplaceable and important role. A battery consists of a housing and multiple cells housed within it. As a core component of new energy vehicles, batteries hold high standards for both safety and longevity. However, as the number of charge and discharge cycles increases, the electrodes within the cells tend to swell, impacting their reliability. Utility Model Content

[0003] The embodiments of the present application provide a battery cell, a battery device, and an electrical device, which can effectively alleviate the expansion problem of the internal electrode of the battery cell and improve the reliability of the battery cell and the electrical device.

[0004] In the first aspect, an embodiment of the present application provides a battery cell, comprising: a shell assembly; an electrode assembly, disposed in the shell assembly and comprising a first pole piece, a second pole piece and a separator, the separator being disposed between the first pole piece and the second pole piece, the electrode assembly comprising a winding axis, the electrode assembly being a core-shaped structure wound around the winding axis, and comprising a plurality of winding layers perpendicular to the winding axis, the winding layers comprising a first pole piece, a separator and a second pole piece stacked; a buffer member, disposed in at least one winding layer and located between the separator and the first pole piece, or between the separator and the second pole piece.

[0005] In the above technical solution, because the buffer is provided within at least one winding layer and is located between the separator and the first electrode sheet, or between the separator and the second electrode sheet, the buffer can act as a buffer between the outer and inner electrode sheets of the electrode assembly, providing space for the expansion of both the inner and outer electrode sheets, effectively alleviating the cumulative effect of the expansion force of the inner electrode sheet on the outer electrode sheet, thereby reducing the tensile force on the outer electrode sheet and thereby lowering the probability of fracture of the outer electrode sheet and improving the reliability of the battery cell. Furthermore, because the buffer is provided within the winding layer, when the electrode assembly is inserted into the shell, the buffer can be assembled into the shell along with the electrode assembly, making assembly of the buffer within the battery cell easier and reducing the overall assembly difficulty of the battery cell.

[0006] In some embodiments of the present application, the electrode assembly includes a main body portion and a tab connected to each other, the main body portion includes a straight portion and an arc-shaped portion connected to each other, and the buffer is provided on the arc-shaped portion.

[0007] In the above technical solution, because the curved portion of the main body is an arc-shaped structure with a varying curvature, stress concentration is more likely to occur during the cyclic expansion process of the electrode assembly, and the curved portion is subjected to greater expansion and tensile forces than other locations on the main body. By arranging the buffer on the curved portion, when the first and / or second pole pieces at the corresponding positions of the curved portion expand, the buffer can compress and absorb energy, reducing the expansion and tensile forces, and providing space required for the first and / or second pole pieces to expand. This helps reduce the risk of pole piece fracture at the location of the curved portion, thereby reducing the probability of expansion and fracture of the entire electrode assembly and improving the reliability of the battery cell. Because the buffer is arranged on the curved portion, the area in which the buffer is installed on the main body can be reduced, saving material and reducing costs. It can also reduce the volume of the buffer, freeing up space within the housing assembly, and reducing the weight of the buffer, thereby reducing the weight of the battery cell as a whole, thereby increasing the volumetric energy density of the battery cell.

[0008] In some embodiments of the present application, the buffer is bonded to the first pole piece or the second pole piece.

[0009] In the above technical solution, the buffer is bonded to the first pole piece or the second pole piece, thereby fixing the buffer on the first pole piece or the second pole piece, which is beneficial to reducing the risk of displacement of the buffer during the winding process of the electrode assembly and reducing the probability of the buffer detaching from the position of the arc portion, which is beneficial to improving the stability of the buffer in the electrode assembly, improving the effect of the buffer on buffering the outermost pole piece of the electrode assembly and inhibiting expansion and fracture, and further improving the reliability of the battery cell.

[0010] In some embodiments of the present application, an adhesive sheet is provided on the end surface of the buffer member facing the isolation membrane. In the winding direction of the arc portion, both ends of the adhesive sheet extend beyond the buffer member and are bonded to the first pole piece or the second pole piece.

[0011] In the above technical solution, the adhesive sheet, as a separate component, can be mass-produced, which is conducive to ensuring controllable adhesion, thereby making the bonding force more uniform when the adhesive sheet is bonded to the first pole piece or the second pole piece, improving the reliability of the buffer being fixed to the first pole piece or the second pole piece, and the fixing method is relatively simple and easy to operate, which is conducive to improving assembly efficiency. Secondly, the buffer can be fixed to the first pole piece or the second pole piece by the adhesive sheet on the basis of being bonded to the first pole piece or the second pole piece, which can further improve the installation reliability of the buffer, reduce the risk of the buffer being separated from the first pole piece or the second pole piece, improve the buffering effect of the buffer on the pole piece where the arc portion is located, and further reduce the probability of expansion and fracture of the outermost pole piece.

[0012] In some embodiments of the present application, the buffer is centrally arranged on the arc-shaped portion in the winding direction of the arc-shaped portion.

[0013] In the above technical solution, since the arc portion of the electrode assembly itself is subject to stress concentration, and the middle of the arc portion is a point of relatively high stress, the buffer is centrally located on the arc portion. This can specifically alleviate the stress concentration phenomenon in the arc portion, allowing the buffer to better absorb and disperse stress, reducing the stress borne by the middle of the arc portion. Secondly, the central location of the buffer on the arc portion also helps balance the stress distribution within the entire electrode assembly. The stress originally concentrated in the middle of the arc portion can be diffused to the surrounding areas, making the stress in various parts of the electrode assembly more uniform, thereby reducing the risk of expansion and fracture of the outer electrode sheet due to high local stress, which helps improve the reliability of the electrode assembly and, in turn, the reliability of the battery cell as a whole.

[0014] In some embodiments of the present application, in the winding direction of the arc portion, the size of the winding layer of the buffer member provided in the arc portion is L1, and the size of the buffer member is L2, wherein 0<L2 / L1<100%.

[0015] In the above technical solution, by setting the ratio of the buffer member's size L2 to the size L1 of the wound layer in which the buffer member is disposed within the curved portion within the aforementioned range, the size of the buffer member does not exceed the size of the wound layer in which the buffer member is disposed within the curved portion. This prevents the buffer member from extending onto the straight portion, thereby reducing the risk of a bend between the buffer member and the first or second electrode sheet within the straight portion, which could lead to stress concentration and fracture of the first or second electrode sheet. This improves the reliability of the electrode assembly when the buffer member is disposed within the wound layer. Since the buffer member does not extend onto the straight portion, it also helps reduce the volume of the buffer member, saving space and reducing the weight of the buffer member, thereby reducing the overall weight of the battery cell, thereby increasing the volumetric energy density of the battery cell.

[0016] In some embodiments of the present application, multiple buffers are provided on the arcuate portion, spaced apart and symmetrically arranged in the winding direction of the arcuate portion. This technical solution can further reduce the volume of the buffers, thereby further saving space and facilitating an increase in the volumetric proportion of the electrode assembly within the housing assembly. It can also further reduce the weight of the buffers, thereby reducing the overall weight of the battery cell, thereby further increasing the volumetric energy density of the battery cell.

[0017] In some embodiments of the present application, the buffer has a center plane in the winding direction of the arc portion, and two buffers are provided on the arc portion. The center plane of the buffer is close to or coincides with a dividing line of one quarter of the arc length of the arc portion.

[0018] In the above technical solution, the location of the quarter dividing line of the arc length of the arc portion is close to the two end edges of the arc portion, and the two end edges of the arc portion are the key points for stress dispersion. By bringing the center plane of the buffer component and the quarter dividing line close to or coinciding, the buffer component can better adapt to the direction of stress transmission, disperse the stress to a wider area, and reduce the degree of local stress concentration. When the electrode assembly is bent and deformed, the two end positions of the arc portion are first subjected to bending stress. The above solution can effectively absorb and buffer the bending stress, reduce the risk of damage to the internal structure of the electrode assembly due to excessive bending, improve the reliability of the electrode assembly, and thus improve the overall reliability of the battery cell. Moreover, the above solution can also form a certain gap between the first pole piece or the second pole piece in the winding layer where the buffer component is located in the middle position of the arc portion, which can provide the space required for the expansion of the middle position of the arc portion, and is also conducive to reducing the probability of stress concentration in the middle position of the arc portion, and can also improve the reliability of the battery cell.

[0019] On the other hand, since the arc portion has an arc-shaped structure and the shell assembly is generally square, a certain gap will be formed between the two ends of the arc portion in the winding direction and the shell assembly. By bringing the center planes of the two buffers and the dividing line of one-quarter of the arc length of the arc portion close to or coinciding, the gap formed between the arc portion and the shell assembly can be fully utilized to arrange the buffers, reducing the probability of the electrode assembly size increasing due to the buffer being arranged in the winding layer, and increasing the space occupied by the electrode assembly in the shell assembly, which is conducive to making the battery cell have a higher volume energy density.

[0020] In some embodiments of the present application, curved portions are provided at opposite ends of the straight portion, and both curved portions are provided with buffers. In this technical solution, by providing buffers on both curved portions, the buffers can provide space required for expansion of the curved portions at opposite ends of the straight portion. Together, the two buffers can provide a larger expansion relief space and provide timely buffering and space required for expansion of each curved portion. This can reduce the risk of expansion and fracture of the outer electrode sheet at the location of the curved portion, further improving the reliability of the electrode assembly, and thus the reliability of the battery cell.

[0021] In some embodiments of the present application, the buffer members of the two arc-shaped portions are provided in the same winding layer, or in different winding layers.

[0022] In the above technical solution, the buffers with two arc-shaped portions are arranged in the same winding layer, so that the buffers can buffer the stress generated in this layer, can timely absorb and disperse the stress, effectively reduce the risk of stress concentration in local areas, better protect the first electrode sheet or the second electrode sheet in this layer, reduce the risk of fracture of the electrode sheet in this layer, and contribute to the consistency within this winding layer, which is beneficial to improving the overall consistency of the battery cell. The buffers with two arc-shaped portions are arranged in different winding layers, which can buffer the stress generated inside the electrode assembly from multiple levels. Since the stress inside the electrode assembly is a complex system, the stresses from different winding layers will overlap and affect each other. By arranging the buffers in different winding layers, it is beneficial to comprehensively buffer the stress of each layer, reduce the accumulation and transmission of stress inside the electrode assembly, better protect the entire electrode assembly, and improve the overall reliability of the battery cell.

[0023] In some embodiments of the present application, the buffer component is provided with a through hole. In this technical solution, when the buffer component is compressed by the first or second pole piece, the through hole provides space for the buffer component to compress and deform, making it easier to compress the buffer component, thereby enhancing the buffer component's cushioning effect and better absorbing expansion. The through hole also helps reduce the weight of the buffer component and the weight of the battery cell, which helps the battery cell have a higher volumetric energy density.

[0024] In some embodiments of the present application, multiple through-holes are arranged in an array on the buffer. In this technical solution, the greater number of through-holes can further enhance the compressibility of the buffer, improve the buffer's cushioning effect, and further reduce the weight of the buffer, thereby further increasing the volumetric energy density of the battery cell.

[0025] In some embodiments of the present application, multiple through-holes are provided in the form of elongated holes, spaced apart on the buffer along or perpendicular to the winding axis. In this technical solution, the larger elongated holes provide more room for the buffer to deform, making it easier to compress and enhancing its cushioning effect. Similarly, the elongated holes also reduce the weight of the buffer, further improving the volumetric energy density of the battery cell.

[0026] In some embodiments of the present application, along the winding axis, the size of the buffer is greater than or equal to the size of the electrode assembly.

[0027] In the above technical solution, along the winding axis, no matter the size of the buffer is greater than or equal to the size of the electrode assembly, the buffer can fully cover the electrode assembly in the winding axis, thereby providing a more comprehensive buffering effect on the first pole piece or the second pole piece in the winding layer, and reducing the probability of local stress concentration in the first pole piece or the second pole piece where the buffer piece is located, thereby reducing the risk of expansion and fracture of the outer pole piece, which is beneficial to further improve the reliability of the battery cell.

[0028] In some embodiments of the present application, the thickness of the buffer is T, where 0mm<T≤100mm. In this technical solution, by setting the thickness T of the buffer within the above range, it is helpful to determine the appropriate thickness range of the buffer, reducing the difficulty of selecting the specifications of the buffer during production. Therefore, the buffer achieves a good cushioning effect while balancing material usage and space occupation, which helps reduce costs and improve the volume energy density of the battery cell.

[0029] In some embodiments of the present application, 0mm<T≤20mm. In this technical solution, by further setting the thickness of the buffer member within the above range, the thickness selection range of the buffer member can be narrowed, the selection difficulty can be reduced, and it is also conducive to selecting a buffer member in a more appropriate range.

[0030] In some embodiments of the present application, the buffer member has a dimension L2 in the winding direction of the arcuate portion, where 0 mm < L2 ≤ 100 mm. In this technical solution, by setting the buffer member dimension L2 within the aforementioned range, it is easier to determine an appropriate width range for the buffer member, reducing the difficulty of selecting the buffer member specifications during production. This ensures that the buffer member achieves a good cushioning effect while balancing material usage and space occupation, thereby reducing costs and increasing the volumetric energy density of the battery cell.

[0031] In some embodiments of the present application, 2 mm ≤ L2 ≤ 50 mm. By further narrowing the value range of the size L2 of the buffer component, the difficulty of selecting the size L2 of the buffer component can be reduced, which is conducive to selecting a buffer component in a more appropriate range.

[0032] In some embodiments of the present application, the buffer component has a dimension L3 in the axial direction of the electrode assembly, where 0 mm < L3 ≤ 1200 mm. This technical solution, by setting the buffer component dimension L3 in the axial direction of the electrode assembly within the aforementioned range, facilitates determining the range of the buffer component dimension L3, reduces the difficulty in selecting the buffer component specification during production, and facilitates reducing production complexity and costs.

[0033] In some embodiments of the present application, 50mm≤L3≤600mm. In this technical solution, by setting the dimension L3 of the buffer member within the above range, the buffer member can provide sufficient support and cushioning, ensure the stability of the winding layer where the buffer member is located, and provide a good cushioning effect, which is conducive to relieving stress and reducing the risk of expansion and fracture of the outer electrode sheet. Under this premise, the material and weight of the buffer member can be balanced, reducing costs and enabling the battery cell to have a higher volume energy density.

[0034] In some embodiments of the present application, in the arc-shaped portion, the second pole piece is a cathode piece, and the buffer is provided between the second pole piece and the isolation membrane.

[0035] In the above technical solution, since a chemical reaction occurs between the first and second pole pieces in the wound layer, if the buffer is to be fixed to the first or second pole piece, it is necessary to minimize the risk of the fixing method affecting the chemical reaction between the first and second pole pieces. Therefore, the buffer is more inclined to be fixed to the first or second pole piece by bonding. With the above solution, the buffer can be easily fixed to the cathode piece by bonding, which is conducive to improving the fixing reliability of the buffer, thereby improving the buffer's buffering effect on the arc portion, reducing the risk of stress concentration, and helping to reduce the probability of expansion and fracture of the outer pole piece where the arc portion is located, thereby improving the reliability of the battery cell.

[0036] In a second aspect, an embodiment of the present application further provides a battery device comprising a battery cell as described in any one of the above.

[0037] In the above technical solution, since the buffer component in the battery cell can be arranged in at least one winding layer, the probability of the outer electrode sheet breaking can be reduced, and the overall reliability of the battery cell can be improved. Therefore, the reliability of the battery device including the battery cell can be improved, which is beneficial to improving the performance of the battery device and extending the service life of the battery device.

[0038] In a third aspect, an embodiment of the present application further provides an electrical device, comprising a battery cell as described in any one of the foregoing items, or a battery device as described in the foregoing items, wherein the battery cell or the battery device is used to store or provide electrical energy.

[0039] In the above technical solution, since the battery cell and the battery device have high reliability, the electrical device including the battery cell or the battery device can also have high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0042] Figure 2 An exploded view of the structure of a battery device provided in some embodiments of the present application;

[0043] Figure 3 Schematic diagram of the internal structure of a battery cell provided in some embodiments of the present application Figure 1 ;

[0044] Figure 4 Schematic diagram of the internal structure of a battery cell provided in some embodiments of the present application Figure 2 ;

[0045] Figure 5 Schematic diagram of assembly of electrode assemblies and buffer components provided in some embodiments of the present application;

[0046] Figure 6 Schematic diagrams of assembly of electrode assemblies and buffer components provided in other embodiments of the present application;

[0047] Figure 7 A schematic diagram of the assembly of a buffer member, an adhesive sheet, and a first pole piece provided in some embodiments of the present application;

[0048] Figure 8 A schematic diagram of the local structure of assembling the electrode assembly and the buffer member provided in some embodiments of the present application;

[0049] Figure 9 A schematic structural diagram of a buffer member provided in some embodiments of the present application;

[0050] Figure 10 A schematic structural diagram of a buffer member provided in some other embodiments of the present application;

[0051] Figure 11 Schematic diagram of the structure of the buffer provided in some other embodiments of the present application.

[0052] icon:

[0053] 1000. Electrical devices;

[0054] 100. Battery;

[0055] 10. Box body;

[0056] 11. First box body; 12. Second box body;

[0057] 20. Battery cells;

[0058] 21. Shell assembly;

[0059] 211, housing;

[0060] 212, cover plate;

[0061] 22. Electrode assembly;

[0062] 221, first pole piece; 222, second pole piece; 223, isolation membrane;

[0063] 201, main body; 2011, straight portion; 2012, curved portion; 2012a, quarter dividing line; 202, tab;

[0064] 23. Buffer; 23a. Through hole;

[0065] 24. Adhesive sheet;

[0066] 200, controller; 300, motor; F1, winding direction; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0067] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0068] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0069] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0070] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0071] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0072] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0073] The term "plurality" used in this application refers to two or more (including two).

[0074] In this application, battery cells may include lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0075] The battery apparatus referred to in the embodiments of this application may refer to a battery assembly comprising one or more battery cells for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or in parallel via a busbar. In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0076] As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing multiple battery cells to form an independent module. As an example, the battery module may be formed by bundling multiple battery cells with a cable tie.

[0077] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more battery cell assemblies housed within the housing. For example, the battery cell assemblies may be battery modules, which may be housed within the housing by securing the battery modules within the housing. For example, the battery cell assembly may also be housed within the housing by directly securing multiple battery cells to the housing. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0078] A battery cell includes a casing, an electrode assembly, and an electrolyte. The casing is used to hold the electrode assembly and the electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet consists of a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector uncoated with the negative active material layer protrudes from the negative current collector coated with the negative active material layer. The negative current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon, silicon, or other materials. To ensure that high currents can pass without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together.

[0079] The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0080] In recent years, new energy vehicles have experienced rapid development. Within the electric vehicle sector, power batteries, as the power source for electric vehicles, play an irreplaceable and important role. A battery consists of a housing and multiple battery cells housed within it. As core components of new energy vehicles, batteries have high requirements for both safety and cycle life. However, in wound-core battery cells, the electrode plates of the electrode assembly expand during the charge and discharge cycles. This expansion increases with the number of cycles, making the outer electrode plates susceptible to stretching and fracture in the later stages of the cycle. Fracturing these plates can lead to reduced capacity, increased internal resistance, and unstable voltage, impacting the performance of the battery cell. Furthermore, it can increase the risk of thermal runaway and short circuits, compromising the safety of the battery cell. In other words, expansion and fracture of the electrode plates within the battery cell can compromise the reliability of the battery cell.

[0081] In typical wound-core battery cells, to mitigate the expansion of the electrode sheets inside the battery cells, a circle of silicone pads is usually placed on the outside of the outer electrode sheets of the electrode assembly. However, since the electrode sheets of the electrode assembly are multi-layered from the inside out, the expansion of each layer of electrode sheets is cumulative, resulting in the largest expansion of the outer electrode sheets, which are also more susceptible to expansion. Therefore, the aforementioned silicone pads are placed on the outside of the outer electrode sheets. On the one hand, the cumulative expansion of the multiple layers of electrode sheets in the electrode assembly still affects the expansion of the outer electrode sheets, and cannot effectively and fundamentally alleviate the problem of large expansion of the outer electrode sheets, thereby effectively improving the reliability of the battery cells. On the other hand, placing silicone pads on the outer electrode sheets is not conducive to the silicone pads being inserted into the shell, which easily increases the difficulty of installation and is not conducive to the assembly of the battery cells. In addition, the silicone pads occupy a large space, affecting the volume energy density of the battery cells.

[0082] Based on the above considerations, in order to solve the problem that the electrode sheets of battery cells are prone to expansion during the cycle process, which causes the outer electrode sheets in the electrode assembly to be prone to fracture, thereby affecting the reliability of the battery cells, the applicant has designed a battery cell comprising: a shell assembly, an electrode assembly and a buffer member, wherein the electrode assembly is arranged in the shell assembly and comprises a first electrode sheet, a second electrode sheet and a separator, the separator is arranged between the first electrode sheet and the second electrode sheet, the electrode assembly comprises a winding axis, the electrode assembly is a core-shaped structure wound around the winding axis, and comprises a plurality of winding layers perpendicular to the winding axis, the winding layers comprising a first electrode sheet, a separator and a second electrode sheet arranged in a stacked manner; the buffer member is arranged in at least one winding layer and is located between the separator and the first electrode sheet, or between the separator and the second electrode sheet.

[0083] In a battery cell of this structure, because the buffer is located within at least one winding layer and between the separator and the first electrode sheet, or between the separator and the second electrode sheet, the buffer can act as a buffer between the outer and inner electrode sheets of the electrode assembly. This provides space for releasing the expansion forces of both the inner and outer electrode sheets, effectively alleviating the cumulative effect of the expansion force of the inner electrode sheet on the outer electrode sheet. This helps reduce the tensile force on the outer electrode sheet, lowers the probability of the outer electrode sheet breaking, and improves the reliability of the battery cell. Furthermore, because the buffer is located within the winding layer, it can be assembled into the housing along with the electrode assembly, making assembly of the buffer within the battery cell easier and reducing the overall assembly difficulty of the battery cell.

[0084] The battery cells and battery devices disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and battery devices disclosed in this application can be used to construct such electrical devices, thereby broadening the scope of application of the battery cells and battery devices.

[0085] The present invention provides an electrical device that uses a battery device as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0086] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device 1000 according to an embodiment of the present application. Figure 1 , Figure 1A schematic diagram of the structure of a vehicle provided for some embodiments of the present application. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle, and the battery device 100 can be provided at the bottom, head or tail of the vehicle. The battery device 100 can be used to power the vehicle. For example, the battery device 100 can serve as an operating power source for the vehicle. The vehicle can also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle during driving.

[0087] In some embodiments of the present application, the battery device 100 can serve not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0088] Please refer to Figure 2 , Figure 2 An exploded view of the structure of a battery device 100 provided in some embodiments of the present application. The battery device 100 includes a housing 10 and a plurality of battery cells 20, which are used to be accommodated in the housing 10. The housing 10 is used to provide an assembly space for the battery cells 20, and the housing 10 can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12, the first housing body 11 and the second housing body 12 covering each other, and the first housing body 11 and the second housing body 12 jointly define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-shaped structure, and the first housing body 11 covers the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define an assembly space; the first housing body 11 and the second housing body 12 can also be hollow structures with one side open, and the open side of the first housing body 11 covers the open side of the second housing body 12. Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0089] In the battery device 100, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can be constructed by first connecting the multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module. The multiple battery modules are then connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10. The battery device 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0090] Please refer to Figure 2 , Figure 2 This is an exploded view of the structure of a battery device 100 provided in some embodiments of the present application. The battery device 100 includes multiple rows of battery cells 20, which are arranged along the length of the housing 10, with each row of battery cells 20 including multiple battery cells 20 arranged along the width of the housing 10; alternatively, the multiple rows of battery cells 20 are arranged along the width of the housing 10, with each row of battery cells 20 including multiple battery cells 20 arranged along the length of the housing 10.

[0091] Each battery cell 20 can be a secondary battery or a primary battery, wherein a secondary battery refers to a battery cell 20 that can be activated by charging the active material after the battery cell is discharged and can continue to be used; it can also be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., which is not limited in the embodiments of the present application. The battery cell 20 can be cylindrical, flat, rectangular or other shapes. For example, in Figure 2 In FIG, the battery cell 20 is in the shape of a rectangular parallelepiped.

[0092] According to some embodiments of the present application, referring to Figure 3 、 Figure 4 and Figure 5The embodiment of the present application provides a battery cell 20, comprising: a shell assembly 21, an electrode assembly 22, and a buffer 23. The electrode assembly 22 is disposed in the shell assembly 21, and comprises a first pole piece 221, a second pole piece 222, and a separator 223. The separator 223 is disposed between the first pole piece 221 and the second pole piece 222. The electrode assembly 22 comprises a winding axis. The electrode assembly 22 is a core-shaped structure wound around the winding axis and comprises a plurality of winding layers perpendicular to the winding axis. The winding layers comprise a first pole piece 221, a separator 223, and a second pole piece 222 stacked. The buffer 23 is disposed in at least one winding layer and is located between the separator 223 and the first pole piece 221, or between the separator 223 and the second pole piece 222.

[0093] The housing assembly 21 may refer to a component that contains the electrode assembly 22 and the electrolyte and protects the electrode assembly 22 and the electrolyte inside. Figure 3 The shell assembly 21 may include but is not limited to a shell 211 and a cover 212, etc., wherein the shell 211 and the cover 212 may be made of but not limited to metal or plastic, the metal material may be but not limited to steel or aluminum, etc., and the plastic material may be but not limited to polycarbonate, polypropylene, etc.

[0094] The explanation of the electrode assembly 22 can be found in the previous text and will not be explained in detail here. The first electrode piece 221 and the second electrode piece 222 may be referred to as an anode piece, and the other may be referred to as a cathode piece. As an example, the first electrode piece 221 may be an anode piece, and the second electrode piece 222 may be a cathode piece.

[0095] "The electrode assembly 22 includes a winding axis, and the electrode assembly 22 is wound into a core shape around the winding axis." It can be understood that the electrode assembly 22 mentioned in the embodiment of the present application is a core, and the winding axis can refer to a direction perpendicular to the winding plane of the core. As an example, refer to Figure 3 , the winding axis can refer to Figure 3 The third direction Z.

[0096] In the electrode assembly 22 of the present embodiment, during the winding process, each layer of the first electrode sheet 221, the second electrode sheet 222, and the separator 223 is stacked and wound together once to form a wound layer. From the inside out, the first electrode sheet 221 is first, followed by the separator 223, and then the second electrode sheet 222. These three layers together constitute a basic wound layer. The electrode assembly 22 may often include multiple wound layers arranged from the inside out.

[0097] The buffer 23 may refer to a component that can deform and absorb energy when subjected to an external force. When the first pole piece 221 and / or the second pole piece 222 expands, the buffer 23 can absorb the expansion force by deformation and provide the space required for the first pole piece 221 or the second pole piece 222 to expand, thereby playing a buffering role. Optionally, the buffer 23 may refer to a structure or component that can be compressed and restore its original shape after the external force is removed. The buffer 23 may be, but is not limited to, a polypropylene material part, a polyethylene material part, a foam, a silicone part or a rubber part, etc. As an example, refer to Figure 9 The buffer member 23 can be a foam sheet.

[0098] The phrase "the buffer 23 is disposed within at least one winding layer" can be understood to mean that the buffer 23 can be disposed within one winding layer, or within two, three, or other winding layers. When the buffer 23 is disposed within multiple winding layers, the buffer 23 can be disposed within the outer winding layer, the middle winding layer, the innermost winding layer, the winding layer between the outermost and middle layers, the winding layer between the middle and innermost layers, and so on, without specific limitation.

[0099] The buffer 23 can be provided between the isolation film 223 of each winding layer and the first pole piece 221, or between the isolation film 223 and the second pole piece 222, and there is no specific limitation here. Figure 5 and Figure 6 The buffer member 23 may be provided between the isolation membrane 223 and the second pole piece 222 .

[0100] It should be noted that in the above-mentioned embodiment, the cross-sectional shape of the winding core of the electrode assembly 22 perpendicular to the winding axis can be but not limited to cylindrical, runway-shaped or rectangular, etc. Correspondingly, the shape of the shell assembly 21 can be but not limited to cylindrical shell, square shell, etc., and no specific restrictions are made here.

[0101] According to the above analysis, since the electrode assembly 22 is in the shape of a winding core, according to its shape, the electrode assembly 22 can generally include an arcuate portion 2012 and a non-arcd portion (such as a straight portion 2011). In the above embodiment, the buffer member 23 can be arranged in the winding layer where the arcuate portion 2012 is located, or it can be arranged in the winding layer where the non-arcd portion is located, or it can be arranged in the winding layer where the arcuate portion 2012 and the non-arcd portion are located at the same time, and there is no restriction here.

[0102] During the cyclic expansion process of the electrode assembly 22, the first electrode piece 221 and / or the second electrode piece 222 will expand, and as the number of cycles increases, the first electrode piece 221 and / or the second electrode piece 222 will expand more, and eventually the large surfaces of the electrode assembly 22 at both ends of the second direction Y will be in close contact with the shell wall of the shell 211 (see FIG. Figure 4), at this time, a tensile force f1 is generated on the first pole piece 221 and / or the second pole piece 222 (see Figure 4 ), especially in the outermost first pole piece 221 and / or the second pole piece 222, the tensile force f1 will be more obvious, and the risk of expansion and fracture will be more likely to occur.

[0103] In the above technical solution, since the buffer 23 is disposed within at least one winding layer and is located between the separator 223 and the first electrode sheet 221, or between the separator 223 and the second electrode sheet 222, the buffer 23 can act as a buffer between the outer and inner electrode sheets of the electrode assembly 22, providing space for the expansion of both the inner and outer electrode sheets. This effectively alleviates the situation where the expansion force of the inner electrode sheet accumulates on the outer electrode sheet, thereby reducing the tensile force on the outer electrode sheet and thus lowering the probability of fracture of the outer electrode sheet, thereby improving the reliability of the battery cell 20. Furthermore, since the buffer 23 is disposed within the winding layer, when the electrode assembly 22 is inserted into the shell, the buffer 23 can be assembled into the shell along with the electrode assembly 22, making the assembly of the buffer 23 within the battery cell 20 simpler and reducing the overall assembly difficulty of the battery cell 20.

[0104] In some embodiments of the present application, reference is made to Figure 3 、 Figure 5 and Figure 6 The electrode assembly 22 includes a main body 201 and a tab 202 connected to each other. The main body 201 includes a straight portion 2011 and an arc-shaped portion 2012 connected to each other. The buffer 23 is provided on the arc-shaped portion 2012 .

[0105] The tab 202 may refer to a metal structural member in the electrode assembly 22 for conducting current. Referring to the above, in the electrode assembly 22, the first pole piece 221 in the multiple winding layers may partially extend and gather to form the tab 202, and the second pole piece 222 in the multiple winding layers may also partially extend and gather to form another tab 202. Due to the different polarities of the first pole piece 221 and the second pole piece 222, the polarities of the tabs 202 formed by the two are also different. As an example, the first pole piece 221 may be an anode piece, and correspondingly, the first pole piece 221 forms a negative tab; the second pole piece 222 may be a cathode piece, and correspondingly, the second pole piece 222 forms a positive tab.

[0106] The main body 201 may refer to the main structure of the electrode assembly 22 excluding the tab 202 .

[0107] The phrase "main body 201 includes a straight portion 2011 and a curved portion 2012 connected to each other" can be understood as meaning that main body 201 may have a straight portion and a curved portion. The straight portion 2011 may have the curved portion 2012 connected to one end or both ends, without specific limitation.

[0108] For example, refer to Figure 5 and Figure 6 The cross-section of the main body 201 perpendicular to the scroll axis can be in the shape of a racetrack, with the straight portion 2011 extending along the first direction X. Curved portions 2012 are provided at both ends of the straight portion 2011 in the first direction X. For another example, the cross-section of the main body 201 perpendicular to the scroll axis can be in the shape of a rectangle, with the four corners of the rectangle forming the curved portions 2012 and the four sides of the rectangle forming the straight portions 2011.

[0109] In the above technical solution, since the arcuate portion 2012 of the main body 201 is an arc-shaped structure with a curvature change, stress concentration is more likely to occur during the cyclic expansion process of the electrode assembly 22, and the arcuate portion 2012 is subjected to greater expansion and tensile forces than other positions of the main body 201. By arranging the buffer member 23 on the arcuate portion 2012, when the first electrode piece 221 and / or the second electrode piece 222 at the position corresponding to the arcuate portion 2012 expands, the buffer member 23 can compress and absorb energy, reducing the expansion and tensile forces, and providing space required for the first electrode piece 221 and / or the second electrode piece 222 to expand, which helps to reduce the risk of electrode piece fracture at the position of the arcuate portion 2012, thereby reducing the probability of expansion and fracture of the electrode assembly 22 as a whole, and improving the reliability of the battery cell 20. Since the buffer 23 is arranged on the arc portion 2012, the area in which the buffer 23 is arranged on the main body 201 can be reduced, which can save materials and reduce costs. It can also reduce the volume of the buffer 23 and save the internal space of the shell assembly 21. At the same time, it can also reduce the weight of the buffer 23, thereby reducing the overall weight of the battery cell 20, thereby improving the volume energy density of the battery cell 20.

[0110] Further, refer to Figure 5 and Figure 6 When the buffer member 23 is positioned on the curved portion 2012, the cross-section of the buffer member 23 perpendicular to the winding axis can be arc-shaped, with the thickness of the arc gradually decreasing from the center toward the ends. This configuration allows the buffer member 23 to adapt to the curved structure of the curved portion 2012, reducing the likelihood of a bend between the buffer member 23 and the first electrode sheet 221 or the second electrode sheet 222 in the winding layer where the curved portion 2012 is located. This reduces the risk of stress concentration, thereby enhancing the buffering effect of the buffer member 23, improving the reliability of the electrode assembly 22, and ultimately, the reliability of the battery cell 20.

[0111] In some embodiments of the present application, the buffer member 23 is bonded to the first pole piece 221 or the second pole piece 222 .

[0112] As mentioned above, the buffer member 23 can be disposed between the first electrode piece 221 and the isolation film 223, in which case the buffer member 23 can be bonded to the first electrode piece 221; the buffer member 23 can also be disposed between the second electrode piece 222 and the isolation film 223, in which case the buffer member 23 can be bonded to the second electrode piece 222. In the above technical solution, no specific limitation is imposed here.

[0113] In the above technical solution, the buffer 23 is bonded to the first pole piece 221 or the second pole piece 222, so that the buffer 23 can be fixed on the first pole piece 221 or the second pole piece 222, which is beneficial to reduce the risk of displacement of the buffer 23 during the winding process of the electrode assembly 22, and reduce the probability of the buffer 23 detaching from the position of the arc portion 2012, which is beneficial to improve the stability of the buffer 23 in the electrode assembly 22, improve the effect of the buffer 23 on buffering the outermost pole piece of the electrode assembly 22 and inhibiting expansion and fracture, and further improve the reliability of the battery cell 20.

[0114] In some embodiments of the present application, reference is made to Figure 5 、 Figure 6 and Figure 7 An adhesive sheet 24 is provided on the end surface of the buffer 23 facing the isolation membrane 223 . In the winding direction F1 of the arc portion 2012 , both ends of the adhesive sheet 24 extend beyond the buffer 23 and are bonded to the first pole piece 221 or the second pole piece 222 .

[0115] Adhesive sheet 24 may be a sheet-like component with an adhesive function. Adhesive sheet 24 may be made of, but is not limited to, organic polymers or rubber. Organic polymers may include, but are not limited to, acrylates and polyurethanes, and rubbers may include, but are not limited to, natural rubber or synthetic rubber. For example, adhesive sheet 24 may be tape.

[0116] “Both ends of the adhesive sheet 24 extend beyond the buffer 23 ” can be understood as that, in the winding direction F1 , the size of the adhesive sheet 24 is larger than that of the buffer 23 , and both ends extend relative to both ends of the buffer 23 .

[0117] “The adhesive sheet 24 is bonded to the first electrode 221 or the second electrode 222” can be understood as when the buffer 23 is provided between the first electrode 221 and the isolation film 223, the adhesive sheet 24 is bonded to the first electrode 221 (see Figure 7 ); When the buffer member 23 is disposed between the second electrode piece 222 and the isolation film 223, the adhesive sheet 24 is bonded to the second electrode piece 222. Optionally, the buffer member 23 may be secured to the first electrode piece 221 or the second electrode piece 222 solely via the adhesive sheet 24. Furthermore, the buffer member 23 may be bonded to the first electrode piece 221 or the second electrode piece 222 and then secured to the first electrode piece 221 or the second electrode piece 222 via the adhesive sheet 24.

[0118] In the above technical solution, the adhesive sheet 24 is a separate component that can be mass-produced, which is conducive to ensuring controllable adhesion, thereby making the bonding force more uniform when the adhesive sheet 24 is bonded to the first pole piece 221 or the second pole piece 222, improving the reliability of the buffer 23 fixed to the first pole piece 221 or the second pole piece 222, and the fixing method is relatively simple and easy to operate, which is conducive to improving assembly efficiency. Secondly, the buffer 23 can be fixed to the first pole piece 221 or the second pole piece 222 by the adhesive sheet 24 on the basis of being bonded to the first pole piece 221 or the second pole piece 222, which can further improve the installation reliability of the buffer 23, reduce the risk of the buffer 23 being separated from the first pole piece 221 or the second pole piece 222, improve the buffering effect of the buffer 23 on the pole piece where the arc portion 2012 is located, and further reduce the probability of expansion and fracture of the outermost pole piece.

[0119] In some embodiments of the present application, reference is made to Figure 5 In the winding direction F1 of the arc-shaped portion 2012 , the buffer member 23 is centrally arranged on the arc-shaped portion 2012 .

[0120] The winding direction F1 can be seen in Figure 5 The buffer member 23 is centrally located on the arc portion 2012, which can be understood as the center of the buffer member 23 being located on the half arc length dividing line of the arc portion 2012 (see Figure 5 ).

[0121] In the above technical solution, since stress concentration exists at the location of the arcuate portion 2012 of the electrode assembly 22, and the middle of the arcuate portion 2012 is a point of relatively high stress, the buffer member 23 is centrally located on the arcuate portion 2012. This can specifically alleviate the stress concentration phenomenon in the arcuate portion 2012, allowing the buffer member 23 to better absorb and disperse stress, thereby reducing the stress borne by the middle of the arcuate portion 2012. Secondly, the central location of the buffer member 23 on the arcuate portion 2012 also helps balance the stress distribution within the entire electrode assembly 22. The stress originally concentrated in the middle of the arcuate portion 2012 can be diffused to the surrounding areas, making the stress in various parts of the electrode assembly 22 more uniform. This reduces the risk of expansion and fracture of the outer electrode sheets due to high local stress, and helps improve the reliability of the electrode assembly 22, and thus improves the reliability of the battery cell 20 as a whole.

[0122] In some embodiments of the present application, reference is made to Figure 8 In the winding direction F1 of the arc portion 2012 , the size of the winding layer of the buffer member 23 provided in the arc portion 2012 is L1 , and the size of the buffer member 23 is L2 , wherein 0<L2 / L1<100%.

[0123] It will be understood that L2 / L1 can be but is not limited to 0.1%, 0.5%, 1%, 1.5%, 5%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, etc.

[0124] In the above technical solution, by setting the ratio of the size L2 of the buffer member 23 to the size L1 of the wound layer in which the buffer member 23 is disposed within the curved portion 2012 within the aforementioned range, the size of the buffer member 23 does not exceed the size of the wound layer in which the buffer member 23 is disposed within the curved portion 2012. This prevents the buffer member 23 from extending onto the straight portion 2011, thereby reducing the risk of the buffer member 23 bending between the first electrode sheet 221 or the second electrode sheet 222 when within the straight portion 2011, thereby reducing the risk of stress concentration and fracture of the first electrode sheet 221 or the second electrode sheet 222. This improves the reliability of the electrode assembly 22 when the buffer member 23 is disposed within the wound layer. Since the buffer member 23 does not extend into the straight portion 2011, the volume of the buffer member 23 is reduced, saving space, and reducing the weight of the buffer member 23, thereby reducing the overall weight of the battery cell 20, thereby increasing the volumetric energy density of the battery cell 20.

[0125] In some embodiments of the present application, reference is made to Figure 6 A plurality of buffer members 23 are provided on the arc portion 2012 , and the plurality of buffer members 23 are spaced apart and symmetrically arranged in the winding direction F1 of the arc portion 2012 .

[0126] The number of buffer members 23 provided on the arc portion 2012 may be, but is not limited to, two, three, four, etc. As an example, refer to Figure 6 , the number of buffer members 23 can be set on the arc portion 2012.

[0127] In the above technical solution, the above solution can further reduce the volume of the buffer 23, thereby further saving space, which is conducive to increasing the volume share of the electrode assembly 22 in the shell assembly 21, and can also further reduce the weight of the buffer 23, thereby reducing the overall weight of the battery cell 20, thereby further improving the volume energy density of the battery cell 20.

[0128] In some embodiments of the present application, reference is made to Figure 6 In the winding direction F1 of the arc portion 2012, the buffer 23 has a center plane, and the buffer 23 is provided with two on the arc portion 2012. The center plane of the buffer 23 and the quarter dividing line 2012a of the arc length of the arc portion 2012 are close to or coincide with each other.

[0129] The "center plane of the buffer member 23" may refer to a plane that divides the buffer member 23 into equal parts along the winding direction F1. Figure 5 The center plane of the buffer member 23 coincides with a quarter dividing line 2012a of the arc length of the arc-shaped portion 2012.

[0130] The “quarter dividing line 2012 a of the arc length of the arc-shaped portion 2012 ” may refer to a dividing line that cuts off a quarter of the arc length of the arc-shaped portion 2012 from the end of the arc-shaped portion 2012 .

[0131] “The center plane of the buffer 23 is close to or coincides with the quarter-dividing line 2012a of the arc length of the arc-shaped portion 2012” can be understood as that the center plane of the buffer 23 can be set close to the quarter-dividing line 2012a of the arc length of the arc-shaped portion 2012, or the center plane of the buffer 23 and the quarter-dividing line 2012a of the arc length of the arc-shaped portion 2012 coincide with each other, that is, the quarter-dividing line 2012a of the arc length of the arc-shaped portion 2012 is located on the center plane of the buffer 23.

[0132] In the above technical solution, the location of the quarter dividing line 2012a of the arc length of the arc portion 2012 is close to the two end edge positions of the arc portion 2012, and the two end edge positions of the arc portion 2012 are the key points for stress dispersion. By bringing the center plane of the buffer 23 and the quarter dividing line 2012a close to or overlapping, the buffer 23 can better adapt to the direction of stress transmission, disperse the stress to a wider area, and reduce the degree of local stress concentration. When the electrode assembly 22 is bent and deformed, the two end positions of the arc portion 2012 are first subjected to bending stress. The above solution can effectively absorb and buffer the bending stress, reduce the risk of the internal structure of the electrode assembly 22 being damaged due to excessive bending, improve the reliability of the electrode assembly 22, and thus improve the overall reliability of the battery cell 20. Moreover, the above solution can also make the first pole piece 221 or the second pole piece 222 form a certain gap in the middle position of the arc portion 2012 in the winding layer where the buffer 23 is located (see Figure 6 ), which can provide the space required for the middle position of the arc portion 2012 to expand, is also beneficial to reducing the probability of stress concentration occurring in the middle position of the arc portion 2012, and can also improve the reliability of the battery cell 20.

[0133] On the other hand, since the arc portion 2012 is an arc-shaped structure, and the shell assembly 21 is generally square, a certain gap is formed between the arc portion 2012 at both ends of the winding direction F1 and the shell assembly 21. By bringing the center plane of the two buffer members 23 and the quarter-length dividing line 2012a of the arc portion 2012 close to or coinciding with each other, the gap formed between the arc portion 2012 and the shell assembly 21 can be fully utilized to arrange the buffer member 23, thereby reducing the probability of the electrode assembly 22 being increased in size in the first direction X and the second direction Y due to the buffer member 23 being arranged in the winding layer (see Figure 6 ), the space occupied by the electrode assembly 22 in the shell assembly 21 can be increased, which is beneficial for the battery cell 20 to have a higher volume energy density.

[0134] In some embodiments of the present application, reference is made to Figure 5 and Figure 6 , arc-shaped portions 2012 are provided at opposite ends of the straight portion 2011 , and both arc-shaped portions 2012 are provided with buffer members 23 .

[0135] Reference Figure 5 and Figure 6 "The opposite ends of the straight portion 2011" may refer to the opposite ends along the first direction X. The opposite ends of the straight portion 2011 are provided with arcuate portions 2012, so that the cross-section of the electrode assembly 22 perpendicular to the winding axis is a racetrack shape, and this winding core structure is relatively simple.

[0136] In the above technical aspect, buffer parts 23 are provided on both arc-shaped portions 2012. The buffer parts 23 can provide the space required for expansion for the arc-shaped portions 2012 at opposite ends of the straight portion 2011 respectively. The two buffer parts 23 can together provide a larger expansion release space, and can also provide buffering effect and space required for expansion for each arc-shaped portion 2012 in time when it expands, which can reduce the risk of expansion and fracture of the outer electrode sheet at the position of the arc-shaped portion 2012, further improve the reliability of the electrode assembly 22, and then improve the reliability of the battery cell 20.

[0137] In some embodiments of the present application, the buffer members 23 of the two arc-shaped portions 2012 are provided in the same winding layer, or in different winding layers.

[0138] In the above technical solution, the buffer members 23 of the two arc-shaped portions 2012 are arranged in the same winding layer, so that the buffer members 23 can buffer the stress generated within this layer, promptly absorb and disperse the stress, effectively reduce the risk of stress concentration in a local area, better protect the first electrode sheet 221 or the second electrode sheet 222 within this layer, reduce the risk of electrode sheet fracture within this layer, and contribute to the consistency within this winding layer, which is beneficial to improving the overall consistency of the battery cell 20. The buffer members 23 of the two arc-shaped portions 2012 are arranged in different winding layers, which can buffer the stress generated within the electrode assembly 22 from multiple levels. Since the stress within the electrode assembly 22 is a complex system, the stresses from different winding layers will superimpose and affect each other. By arranging the buffer members 23 in different winding layers, it is beneficial to comprehensively buffer the stress of each layer, reduce the accumulation and transmission of stress within the electrode assembly 22, better protect the entire electrode assembly 22, and improve the overall reliability of the battery cell 20.

[0139] In some embodiments of the present application, reference is made to Figure 10 and Figure 11 The buffer member 23 is provided with a through hole 23a.

[0140] The through hole 23a may refer to a hole that passes through the buffer member 23 along the thickness direction of the buffer member 23. The shape of the through hole 23a may be, but is not limited to, a circular hole, a rectangular hole, a circular hole, or an elongated hole, etc., and is not specifically limited here.

[0141] In the above technical solution, when the buffer member 23 is compressed by the first electrode piece 221 or the second electrode piece 222, the through hole 23a provides the space required for the compression and deformation of the buffer member 23, making it easier to compress the buffer member 23, thereby improving the buffering effect of the buffer member 23 and better absorbing expansion. The through hole 23a also helps to reduce the weight of the buffer member 23 and the weight of the battery cell 20, which helps to achieve a higher volumetric energy density of the battery cell 20.

[0142] In some embodiments of the present application, reference is made to Figure 10 There are multiple through holes 23 a, and the multiple through holes 23 a are arranged in an array on the buffer member 23.

[0143] “Multiple through holes 23 a are arranged in an array on the buffer 23 ” can be understood as that the multiple through holes 23 a are arranged in multiple rows along the second direction Y on the buffer 23 , and the through holes 23 a in each row are arranged in multiple rows along the third direction Z.

[0144] In the above technical solution, more through holes 23a are provided, which can further enhance the compressibility of the buffer 23 and improve the buffering effect of the buffer 23, and can also further reduce the weight of the buffer 23, thereby further improving the volume energy density of the battery cell 20.

[0145] In some embodiments of the present application, reference is made to Figure 11 There are multiple through holes 23a, which are long strip holes. The multiple through holes 23a are spaced apart on the buffer member 23 along the winding axis or in a direction perpendicular to the winding axis.

[0146] Reference Figure 11 , the winding axis can refer to Figure 11 The third direction Z of the winding axis can be the second direction Y. That is, the through hole 23a can be a long hole extending along the second direction Y, and multiple through holes 23a are arranged at intervals along the third direction Z; the through hole 23a can also be a long hole extending along the third direction Z, and multiple through holes 23a are arranged at intervals along the second direction Y (see Figure 11 ).

[0147] In the above technical solution, the elongated holes have a larger size, which can provide more space for the buffer member 23 to deform, and can make the buffer member 23 more easily compressed, thereby improving the cushioning effect of the buffer member 23. Similarly, the elongated holes also have a better weight reduction effect on the buffer member 23, which is conducive to further improving the volume energy density of the battery cell 20.

[0148] In some embodiments of the present application, along the winding axis, the size of the buffer member 23 is greater than or equal to the size of the electrode assembly 22 .

[0149] Referring to the above description, the winding axis can be Figure 3 、 Figures 9 to 11 The third direction Z can be understood as the height direction of the electrode assembly 22. "The size of the buffer 23 is greater than or equal to the size of the electrode assembly 22" can be understood as that, along the winding axis, the size of the buffer 23 can be greater than the size of the electrode assembly 22, or the size of the buffer 23 is equal to the size of the electrode assembly 22.

[0150] In the above technical solution, along the winding axis, no matter the size of the buffer 23 is greater than or equal to the size of the electrode assembly 22, the buffer 23 can fully cover the electrode assembly 22 in the winding axis, thereby providing a more comprehensive buffering effect on the first pole piece 221 or the second pole piece 222 in the winding layer, and reducing the probability of local stress concentration in the first pole piece 221 or the second pole piece 222 where the buffer 23 is located, thereby reducing the risk of expansion and fracture of the outer pole piece, which is beneficial to further improve the reliability of the battery cell 20.

[0151] In some embodiments of the present application, reference is made to Figure 7 The thickness of the buffer member 23 is T, where 0mm<T≤100mm.

[0152] T can be, but is not limited to, 0.2mm, 0.4mm, 0.7mm, 0.8mm, 1mm, 2mm, 5mm, 8mm, 12mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 99mm, 100mm, and the like.

[0153] It is understood that the thickness T of the buffer member 23 can be selected to a corresponding value based on the size of the electrode assembly 22. However, generally, the thickness T of the buffer member 23 does not exceed 100 mm. If the thickness T of the buffer member 23 exceeds 100 mm, the buffer member 23 will not only provide a good buffering effect but also result in material waste and occupy more space, thereby reducing the volumetric energy density of the battery cell 20.

[0154] In the above technical solution, by setting the thickness T of the buffer 23 within the above range, it is helpful to determine the appropriate thickness range of the buffer 23, reducing the difficulty of selecting the specifications of the buffer 23 during production, so that the buffer 23 has a good buffering effect while balancing the material usage and occupied space, which is helpful to reduce costs and improve the volume energy density of the battery cell 20.

[0155] In some embodiments of the present application, 0 mm < T ≤ 20 mm. In this embodiment, T may be, but is not limited to, 0.1 mm, 0.15 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 1.5 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 12.5 mm, 13.5 mm, 14 mm, 14.5 mm, 15.5 mm, 16 mm, 16.5 mm, 17 mm, 17.5 mm, 18 mm, 18.5 mm, 19 mm, 19.5 mm, and the like.

[0156] In the above technical solution, by further setting the thickness T of the buffer 23 within the above range, the thickness selection range of the buffer 23 can be narrowed, the selection difficulty is reduced, and it is also conducive to selecting a buffer 23 in a more appropriate range.

[0157] In some embodiments of the present application, reference is made to Figure 8 In the winding direction F1 of the arc portion 2012, the size of the buffer member 23 is L2, wherein 0mm<L2≤100mm.

[0158] L2 can be, but is not limited to, 0.2mm, 0.4mm, 0.7mm, 0.8mm, 1mm, 2mm, 5mm, 8mm, 12mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 99mm, 100mm, and the like.

[0159] It is understood that the dimension L2 of the buffer member 23 can be selected accordingly based on the size of the curved portion 2012 in the winding direction F1. However, generally, due to the size of the electrode assembly 22 in the winding direction F1, the dimension L2 of the buffer member 23 does not exceed 100 mm. If the dimension L2 of the buffer member 23 exceeds 100 mm, the buffer member 23 will occupy more space, reducing the volumetric energy density of the battery cell 20.

[0160] In the above technical solution, by setting the size L2 of the buffer 23 within the above range, it is helpful to determine the appropriate width range of the buffer 23, reducing the difficulty of selecting the specifications of the buffer 23 during production, so that the buffer 23 has a good buffering effect while balancing the material usage and occupied space, which is helpful to reduce costs and improve the volume energy density of the battery cell 20.

[0161] In some embodiments of the present application, 2 mm ≤ L2 ≤ 50 mm.

[0162] L2 may be, but is not limited to, 2mm, 3mm, 4mm, 6mm, 7mm, 9mm, 12mm, 14mm, 16mm, 18mm, 20mm, 24mm, 30mm, 32mm, 40mm, 45mm, 48mm, 50mm, etc. If L2 is less than 2mm, the width of the buffer member 23 in the winding direction F1 is too small, and the buffering effect cannot be effectively achieved, and the effect of relieving stress concentration is not obvious. If L2 is greater than 50mm, the width of the buffer member 23 in the winding direction F1 is too large. While achieving a good buffering effect, it is likely to be larger in size, occupying a larger space, and increasing material consumption, which is not conducive to reducing costs and improving the volumetric energy density of the battery cell 20.

[0163] In the above technical solution, by further narrowing the value range of the size L2 of the buffer member 23, the difficulty of selecting the size L2 of the buffer member 23 can be reduced, which is conducive to selecting the buffer member 23 in a more appropriate range.

[0164] In some embodiments of the present application, reference is made to Figure 3 and Figure 9 In the winding axial direction of the electrode assembly 22 , the size of the buffer member 23 is L3, where 0mm<L3≤1200mm.

[0165] The winding axis of the electrode assembly 22 may refer to Figure 3 The dimension L3 of the buffer member 23 can be referred to in the third direction Z. Figure 9 In the above embodiment, L3 can be, but is not limited to, 1mm, 5mm, 10mm, 15mm, 20mm, 30mm, 50mm, 80mm, 120mm, 150mm, 200mm, 220mm, 240mm, 300mm, 320mm, 350mm, 400mm, 420mm, 500mm, 560mm, 600mm, 650mm, 700mm, 750mm, 800mm, 850mm, 900mm, 950mm, 980mm, 1000mm, 1100mm, 1150mm, 1200mm, etc. It is understood that the size L3 of the buffer 23 can be selected to a corresponding value based on the size of the electrode assembly 22 in the winding axis direction, but generally will not exceed 1200mm. Otherwise, the buffer 23 may be large in size, resulting in excessive material consumption.

[0166] In the above technical solution, by setting the dimension L3 of the buffer 23 in the winding axis direction of the electrode assembly 22 within the above range, it is helpful to determine the range of the dimension L3 of the buffer 23, reduce the difficulty of selecting the specifications of the buffer 23 during production, and help reduce production difficulty and reduce costs.

[0167] In some embodiments of the present application, 50 mm ≤ L3 ≤ 600 mm.

[0168] L3 can be but is not limited to 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 300mm, 320mm, 340mm, 350mm, 360mm, 380mm, 400mm, 420mm, 460mm, 500mm, 520mm, 540mm, 560mm, 580mm, 600mm, etc. It is understandable that if L3 is less than 50mm, the size L3 of the buffer 23 is too small to provide sufficient support and buffering, which is not conducive to ensuring the stability of the winding layer at the location of the buffer 23, nor can it provide a good buffering effect, which is not conducive to alleviating stress. If L3 is greater than 600mm, the size L3 of the buffer 23 is too large, which can easily lead to excessive performance of the buffer 23, resulting in material waste, and further leading to a larger overall weight of the battery cell 20, which is not conducive to improving the volume energy density of the battery cell 20.

[0169] In the above technical solution, by setting the size L3 of the buffer 23 within the above range, the buffer 23 can provide sufficient support and buffering effect, and ensure the stability of the winding layer where the buffer 23 is located. It can also play a better buffering role, which is beneficial to relieve stress and reduce the risk of expansion and fracture of the outer electrode. Under this premise, the material and weight of the buffer 23 can also be balanced and controlled, the cost can be reduced, and the battery cell 20 can have a higher volume energy density.

[0170] In some embodiments of the present application, in the arc-shaped portion 2012 , the second electrode piece 222 is a cathode piece, and the buffer member 23 is disposed between the second electrode piece 222 and the isolation membrane 223 .

[0171] It is understandable that due to the different material properties of the cathode and anode sheets, the cathode sheet (positive electrode sheet) is usually composed of a positive electrode active material, a conductive agent, and a binder, and is coated on a current collector (usually aluminum foil). The binder used in the cathode sheet is usually more likely to interact with adhesives such as glue and other adhesives, which is beneficial to the adhesion of the buffer 23. Moreover, the particles of the active material and conductive agent in the cathode sheet are relatively uniformly distributed, and the surface is relatively flat. The contact surface between the buffer 23 and the cathode sheet is large, which is beneficial for the glue and other adhesives to better fill the gap between the buffer 23 and the cathode sheet. In other words, the second electrode sheet 222 is the cathode sheet, which can facilitate the buffer 23 to be fixed to the second electrode sheet 222 by bonding.

[0172] In the above technical solution, since a chemical reaction occurs between the first electrode piece 221 and the second electrode piece 222 in the wound layer, if the buffer 23 is to be fixed to the first electrode piece 221 or the second electrode piece 222, it is necessary to minimize the risk of the fixing method affecting the chemical reaction between the first electrode piece 221 and the second electrode piece 222. Therefore, the buffer 23 is more inclined to be fixed to the first electrode piece 221 or the second electrode piece 222 by bonding. Through the above solution, the buffer 23 can be easily fixed to the cathode piece by bonding, which is conducive to improving the fixing reliability of the buffer 23, thereby improving the buffering effect of the buffer 23 on the arc portion 2012, reducing the risk of stress concentration, and helping to reduce the probability of expansion and fracture of the outer electrode piece where the arc portion 2012 is located, thereby improving the reliability of the battery cell 20.

[0173] Example 1

[0174] The battery cell 20 provided according to an embodiment of the present application includes an electrode assembly 22 and a buffer member 23 .

[0175] The electrode assembly 22 has a coiled core structure and includes a stacked anode sheet, a separator 223, and a cathode sheet. The anode sheet, separator 223, and cathode sheet are stacked and wound to form a coiled core. The electrode assembly 22 includes a straight portion 2011 and curved portions 2012 located at both ends of the straight portion 2011. The buffer member 23 is a flat, rectangular cushion made of a compressible material and located in the middle of the coiled layer between the two curved portions 2012. The cushion is located between the separator 223 and the cathode sheet and is fixed to the cathode sheet by bonding.

[0176] In the above technical solution, at the end of the cycle of the electrode assembly 22, the large top shell of the electrode assembly 22, where the arc-shaped portion 2012 of the electrode assembly 22 is located, will continue to expand. The expansion of the electrode will generate a pulling force on the electrode. When the pulling force reaches the limit that the electrode can withstand, the electrode will be broken. The buffer pad can allow space for the electrode to expand, so that the electrode will not be stretched and cause it to break.

[0177] Example 2

[0178] The structure of the battery cell 20 of the second embodiment is substantially the same as that of the battery cell 20 of the first embodiment, except that two buffer pads are provided in the winding layer at the location of each arc portion 2012 , and the two buffer pads are respectively provided near the two ends of the arc portion 2012 .

[0179] The embodiment of the present application further provides a battery device 100 , comprising a battery cell 20 as described in any of the above embodiments.

[0180] In the above technical solution, since the buffer member 23 in the battery cell 20 can be provided in at least one winding layer, the probability of the outer electrode sheet being broken can be reduced, and the overall reliability of the battery cell 20 can be improved. This can improve the reliability of the battery device 100 including the battery cell 20, and is conducive to improving the performance of the battery device 100 and extending the service life of the battery device 100.

[0181] The embodiment of the present application further provides an electrical device 1000 , comprising a battery cell 20 as in any of the above embodiments, or a battery device 100 as in any of the above embodiments, wherein the battery cell 20 or the battery device 100 is used to store or provide electrical energy.

[0182] In the above technical solution, since the battery cell 20 and the battery device 100 have high reliability, the electrical device 1000 including the battery cell 20 or the battery device 100 also has high reliability, which is conducive to the electrical device 1000 to operate reliably.

[0183] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0184] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: housing assembly; an electrode assembly disposed within the housing assembly and comprising a first electrode piece, a second electrode piece, and a separator, wherein the separator is disposed between the first electrode piece and the second electrode piece, the electrode assembly comprising a winding axis, the electrode assembly being a core-shaped structure wound about the winding axis, and comprising a plurality of winding layers perpendicular to the winding axis, the winding layers comprising the first electrode piece, the separator, and the second electrode piece stacked together; The buffer is provided in at least one of the winding layers and is located between the isolation membrane and the first pole piece, or between the isolation membrane and the second pole piece.

2. The battery cell according to claim 1, wherein: The electrode assembly includes a main body portion and a tab connected to each other. The main body portion includes a straight portion and an arc-shaped portion connected to each other. The buffer is provided on the arc-shaped portion.

3. The battery cell according to claim 2, characterized in that: The buffer component is bonded to the first pole piece or the second pole piece.

4. The battery cell according to claim 2 or 3, characterized in that: An adhesive sheet is provided on the end surface of the buffer member facing the isolation membrane. In the winding direction of the arc portion, both ends of the adhesive sheet extend beyond the buffer member and are bonded to the first pole piece or the second pole piece.

5. The battery cell according to claim 2 or 3, characterized in that: In the winding direction of the arc-shaped portion, the buffer component is centrally arranged on the arc-shaped portion.

6. The battery cell according to claim 5, characterized in that In the winding direction of the arc-shaped portion, the size of the winding layer of the buffer member provided in the arc-shaped portion is L1, and the size of the buffer member is L2, wherein 0<L2 / L1<100%.

7. The battery cell according to claim 2 or 3, characterized in that: A plurality of buffer members are provided on the arc portion, and the plurality of buffer members are spaced apart and symmetrically arranged in the winding direction of the arc portion.

8. The battery cell according to claim 7, characterized in that In the winding direction of the arc-shaped portion, the buffer has a center plane, two buffers are provided on the arc-shaped portion, and the center plane of the buffer is close to or coincides with a quarter dividing line of the arc length of the arc-shaped portion.

9. The battery cell according to claim 2, characterized in that: The arc-shaped portions are provided at opposite ends of the straight portion, and the buffering member is provided at both of the arc-shaped portions.

10. The battery cell according to claim 9, characterized in that The buffer members of the two arc-shaped portions are provided in the same winding layer or in different winding layers.

11. The battery cell according to claim 1, characterized in that The buffer member is provided with a through hole.

12. The battery cell according to claim 11, characterized in that There are a plurality of through holes, and the plurality of through holes are arranged in an array on the buffer.

13. The battery cell according to claim 11, characterized in that There are multiple through holes, which are elongated holes. The multiple through holes are spaced apart on the buffer member along the winding axis or in a direction perpendicular to the winding axis.

14. The battery cell according to claim 1, characterized in that Along the winding axis, the size of the buffer member is greater than or equal to the size of the electrode assembly.

15. The battery cell according to claim 1, characterized in that The thickness of the buffer member is T, wherein 0mm<T≤100mm.

16. The battery cell according to claim 15, characterized in that 0mm<T≤20mm.

17. The battery cell according to claim 2, characterized in that In the winding direction of the arc portion, the size of the buffer member is L2, wherein 0mm<L2≤100mm.

18. The battery cell according to claim 17, characterized in that 2mm≤L2≤50mm.

19. The battery cell according to claim 1, characterized in that In the winding axial direction of the electrode assembly, the size of the buffer member is L3, wherein 0mm<L3≤1200mm.

20. The battery cell according to claim 19, characterized in that 50mm≤L3≤600mm.

21. The battery cell according to claim 2, characterized in that In the arc-shaped portion, the second pole piece is a cathode piece, and the buffer is provided between the second pole piece and the isolation membrane.

22. A battery device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 21.

23. An electrical device, characterized in that: The battery cell according to any one of claims 1 to 21, or the battery device according to claim 22, wherein the battery cell or the battery device is used to store or provide electrical energy.

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