Buffer, battery cell, battery and electric device

Abstract

A buffer member (200), a battery cell (100), a battery (1000) and an electric device (2000), the buffer member (200) being used inside the battery cell (100), the battery cell (100) comprising an electrode assembly (120), the buffer member (200) having a pressure-bearing surface (201) facing or facing away from the electrode assembly (120), the pressure-bearing surface (201) being provided with a clearance groove (202).

Description

Buffer, battery cell, battery and electrical device Technical Field

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

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

[0003] During the battery's cycle operation, the electrode assembly will expand repeatedly, and the expansion force will act on the outer shell, causing the outer shell to swell and deform, affecting the battery's service life.

[0004] Summary of the Invention

[0005] In view of the above problems, the present application provides a buffer, a battery cell, a battery and an electrical device, which can alleviate the problem of expansion force during battery use.

[0006] In a first aspect, the present application provides a buffer component for use inside a battery cell, wherein the battery cell includes a shell and an electrode assembly, and the buffer component has a pressure-bearing surface facing or facing away from the electrode assembly, and the pressure-bearing surface is provided with an air-avoiding groove.

[0007] In the technical solution of the embodiment of the present application, by providing an air-avoiding groove on the pressure-bearing surface of the buffer, the effective area of ​​the buffer can be reduced, so that the compressibility of the buffer can be improved on the basis of satisfying good support; by placing the buffer in the battery cell, during the battery manufacturing process, the buffer has a strong supporting ability, which can meet the requirements of anti-deformation performance in vacuum baking; during the cycle of the battery cell, the buffer can provide a strong supporting ability, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, and alleviate the problem of lithium or sodium precipitation during the cycle; in the later stage of the battery cell cycle, the buffer can be greatly compressed, reducing the space occupied by the buffer in the outer shell, ensuring the expandable space of the electrode assembly to a certain extent, reducing the expansion force of the battery cell, and improving the service life of the battery cell.

[0008] In some embodiments, the buffer member includes a support plate and a plurality of buffer blocks, the buffer blocks being disposed on the support plate, the plurality of buffer blocks being spaced apart, and the gaps between adjacent two buffer blocks forming the air-avoiding grooves. In the above technical solution, by configuring the buffer member to include a plurality of buffer blocks, the plurality of buffer blocks are spliced ​​and combined with the support plate to form the entire buffer member, and each buffer block has a simple structure and a simple manufacturing process, thereby facilitating manufacturing and forming.

[0009] In some embodiments, the buffer block is fixedly connected to the support plate. In the above technical solution, multiple buffer blocks can be directly fixed on the support plate to achieve combined assembly of the buffer components and improve the stability of the buffer components.

[0010] In some embodiments, the buffer block is bonded to the support plate. In the above technical solution, multiple buffer blocks can be directly bonded to the support plate to achieve combined assembly of the buffer component, which simplifies the assembly process and facilitates assembly and molding, thereby reducing the manufacturing difficulty and manufacturing cost of the entire buffer component.

[0011] In some embodiments, the plurality of buffer blocks on one side of the support plate are spaced apart along the length and / or width of the support plate. In the above technical solution, the buffer member provides uniform support for the electrode assembly, resulting in more uniform compression deformation, thereby effectively alleviating the expansion force of the battery cells.

[0012] In some embodiments, the distance L1 between two adjacent buffer blocks is not greater than 20 mm. In the above technical solution, the problem of uneven local stress caused by the large distance between the two buffer blocks can be avoided, thereby improving the supporting effect of the buffer component.

[0013] In some embodiments, the thickness of the support plate ranges from 30 μm to 200 μm. This technical solution not only avoids, to a certain extent, the problem of excessive space occupation and difficulty in compressing the buffer due to excessive thickness, but also improves the support effect on the buffer block and the supporting capacity of the buffer, thereby meeting the requirements for anti-deformation performance during vacuum baking; or during the cycling of the battery cell, the buffer can provide strong support and reduce deformation of the pole piece.

[0014] In some embodiments, the compression rate of the support plate at 1 MPa is not greater than 5%. In the above technical solution, by limiting the compression rate of the support plate to within 5%, the support plate can achieve a reliable support effect on the buffer block, thereby improving the support performance of the buffer.

[0015] In some embodiments, the support plate is made of at least one of high-density polyethylene, polymethacrylate, polyethylene terephthalate, and polytetrafluoroethylene. In the above technical solution, by using the above materials, the support plate can achieve a reliable support effect on the buffer block, thereby improving the support performance of the buffer component.

[0016] In some embodiments, the buffer member is a buffer block, and a portion of the outer surface of the buffer block is recessed inward to form a groove, which serves as the air escape groove. In the above technical solution, by designing the buffer member as an integral structural member and forming the air escape groove by digging, manufacturing is facilitated, and the number of assembly steps for the buffer member can be reduced, thereby reducing assembly workload and manufacturing costs.

[0017] In some embodiments, the grooves include a plurality of grooves, which are spaced apart along the length and / or width of the buffer. This technical solution allows for a more uniform arrangement of the grooves, thereby ensuring more uniform support for the electrode assembly from the buffer and more uniform compression deformation, thereby effectively mitigating the expansion force of the battery cells.

[0018] In some embodiments, each groove has a length L2 dimension in the length direction of the buffer, and a width L3 dimension in the width direction of the buffer, wherein L2 is no greater than 20 mm, and L3 is no greater than 20 mm. In the above technical solution, the buffer can have better support and improve the compressibility of the buffer.

[0019] In some embodiments, the grooves are formed into strip-shaped grooves extending along the length direction or the width direction of the buffer. In the above technical solution, the number of grooves is reduced, the structure of the buffer is simplified, and the manufacturing and molding of the buffer is facilitated while ensuring that the buffer has better support and higher compressibility.

[0020] In some embodiments, the material of the buffer block includes at least one of polyethylene, polypropylene, polyurethane, and silicone rubber. In the above technical solution, by using such foam material, the compressibility of the buffer can be improved while reducing the manufacturing cost.

[0021] In some embodiments, the air-avoidance grooves are provided on opposite sides of the buffer member in the thickness direction, and the air-avoidance grooves are arranged relative to each other in the thickness direction of the buffer member. In the above technical solution, when the electrode assembly expands, the buffer member can be prevented from moving and deforming in its length or width direction, thereby improving the stability of the buffer member and thereby enhancing the reliability of the buffer member's support.

[0022] In some embodiments, the area of ​​the pressure-bearing surface of the buffer is S1, and the area of ​​the air-avoidance groove is S2, where S2 / S1 ranges from 0% to 70%. In the above technical solution, the effective area of ​​the buffer can be reduced and the compressibility of the buffer can be increased, so that the buffer has both good anti-deformation ability and high compressibility, thereby reducing the expansion force of the battery cell in the later stage.

[0023] In some embodiments, the range of S2 / S1 is 20%-50%. In the above technical solution, the buffer can further have good anti-deformation ability and high compressibility, thereby reducing the expansion force of the battery cell in the later stage.

[0024] In some embodiments, the thickness of the buffer is H1, the dimension of the air-avoiding groove in the thickness direction of the buffer is H2, and the range of H2 / H1 is 0-90%. In the above technical solution, the buffer can have both good anti-deformation ability and high compressibility, thereby reducing the expansion force of the battery cell in the later stage.

[0025] In some embodiments, H2 / H1 is in the range of 30-85%. In the above technical solution, the buffer can further have good anti-deformation ability and high compressibility, thereby reducing the expansion force of the battery cell in the later stage.

[0026] In some embodiments, the compression rate of the buffer at 1 MPa is greater than 60%. In the above technical solution, the buffer can be compressed and deformed as the electrode assembly expands to absorb the expansion of the electrode assembly as much as possible and reduce the expansion force of the battery cell in the later stage of the cycle.

[0027] In the second aspect, the present application provides a battery cell, comprising a shell, an electrode assembly, and a buffer provided according to the first aspect of the present application, wherein the buffer and the electrode assembly are both arranged in the shell. In the above technical solution, by adopting the above buffer, during the battery manufacturing process, the buffer has a strong supporting capacity, which can meet the requirements of anti-deformation performance during vacuum baking; in the early stage of the battery cell cycle, the buffer can provide a strong supporting capacity, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, and alleviate the problem of lithium or sodium precipitation during the cycle; in the late stage of the battery cell cycle, the buffer can be greatly compressed, reducing the space occupied by the buffer in the shell, ensuring the expandable space of the electrode assembly to a certain extent, reducing the expansion force of the battery cell, and improving the service life of the battery cell.

[0028] In some embodiments, the buffer is provided between the housing and the electrode assembly. In the above technical solution, the buffer is provided between the housing and the electrode assembly, which facilitates installation and can reduce the stress on the housing when the electrode assembly expands, effectively reducing the probability of housing deformation.

[0029] In some embodiments, the battery cell includes multiple electrode assemblies, and the buffer is disposed between two adjacent electrode assemblies. In the above technical solution, by disposing the buffer between the electrode assemblies, the buffer can effectively absorb the expansion of the electrode assemblies and reduce the stress on the outer shell when the electrode assemblies expand.

[0030] In some embodiments, the battery cell group margin ranges from 96% to 105%. In the above technical solution, by using the above-mentioned buffer, the battery cell group margin is maintained between 96% and 105%. That is, in the thickness direction of the battery cell, the buffer and the electrode assembly can roughly fill the entire inner cavity of the shell, thereby ensuring to a certain extent that the buffer can effectively support the electrode assembly, reducing the problem of interface abnormalities such as electrode wrinkling caused by the failure of the buffer to support the electrode assembly.

[0031] In some embodiments, the ratio of the thickness of the buffer member to the thickness of the electrode assembly is in the range of 2%-15%. In the above technical solution, the energy density of the battery cell can be increased, and the buffer member can play an effective buffering role, reducing the expansion force exerted on the outer shell when the electrode assembly expands, effectively reducing the probability of outer shell deformation.

[0032] In some embodiments, the electrode assembly includes a plurality of pole pieces arranged in a wound manner and the outer peripheral surface of the electrode assembly includes a straight portion and a bend portion connected to the end of the straight portion, and at least one of the straight portion and the bend portion is arranged opposite to the buffer member.

[0033] In the above technical solution, the buffer component can buffer and support at least one of the straight portion and the curved portion, thereby reducing the risk of bridge breakage and lithium deposition of the electrode assembly.

[0034] In some embodiments, the electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked along a first direction, and the buffer is disposed opposite to a surface of at least one side of the electrode assembly along the first direction.

[0035] In the above technical solution, the buffer component can effectively buffer and support the laminated electrode assembly, and the buffer component requires a small area and has a low cost.

[0036] In some embodiments, the opening of the air-avoidance groove is formed on the pressure-bearing surface, and the electrode sheets in the region of the electrode assembly facing the pressure-bearing surface are stacked in a direction perpendicular to the pressure-bearing surface. In the above technical solution, during use, the electrode sheets are more likely to expand along the stacking direction. By having the electrode sheets in the region facing the pressure-bearing surface stacked in a direction perpendicular to the pressure-bearing surface, the pressure-bearing surface can more fully provide cushioning and support to the electrode sheets, thereby improving the effect of reducing electrode sheet wrinkling.

[0037] In a third aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0038] In a fourth aspect, the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0039] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0041] FIG1 is a schematic diagram of an electric device in the related art;

[0042] FIG2 is a schematic diagram of a battery in the related art;

[0043] FIG3 is a schematic diagram of a battery cell in the related art;

[0044] FIG4 is a schematic diagram of a buffer member according to some embodiments of the present application;

[0045] FIG5 is a schematic diagram of a partial structure of the embodiment shown in FIG4 ;

[0046] FIG6 is a schematic diagram of buffer members according to other embodiments of the present application;

[0047] FIG7 is a schematic diagram of buffer members according to some other embodiments of the present application;

[0048] FIG8 is a cross-sectional view of the embodiment shown in FIG7;

[0049] FIG9 is a schematic diagram of a buffer member according to some further embodiments of the present application;

[0050] FIG10 is a schematic diagram of buffer members according to other embodiments of the present application;

[0051] FIG11 is a cross-sectional view of the embodiment shown in FIG10 ;

[0052] FIG12 is a schematic diagram of buffer members according to some other embodiments of the present application;

[0053] FIG13 is a cross-sectional view of the embodiment shown in FIG12;

[0054] FIG14 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0055] FIG15 is a schematic diagram of a battery cell provided in some other embodiments of the present application;

[0056] FIG16 is a schematic diagram of a battery cell provided in some other embodiments of the present application;

[0057] FIG17 is a schematic diagram of an electrode assembly according to some embodiments of the present application.

[0058] Figure 1: Battery 1000, electrical device 2000, battery cell 100, outer shell 110, housing 111, end cover 112, electrode assembly 120, positive electrode sheet 1201, negative electrode sheet 1202, straight portion 121, bend portion 122, buffer 200, pressure-bearing surface 201, air-avoiding groove 202, support plate 10, buffer block 20, groove 21. DETAILED DESCRIPTION

[0059] 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.

[0060] 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 only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The term "plurality" used in this application refers to two or more (including two).

[0066] In this application, a battery refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the batteries mentioned in this application may include battery modules or battery packs. Some batteries may include a casing for enclosing one or more battery cells or multiple battery modules. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells. Of course, some batteries may not include the above-mentioned casing and are directly installed in the battery installation compartment of the electrical device.

[0067] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., 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.

[0068] For example, a battery cell may include a housing, an electrode assembly, and an electrolyte, wherein the housing is used to contain the electrode assembly and the electrolyte. The electrode assembly is composed 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, and 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.

[0069] 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.

[0070] 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 present invention is not limited thereto.

[0071] Battery cells can be equipped with terminals and other components connected to the tabs, serving as electrical connections. Furthermore, they can have pressure relief features. When the internal pressure in a battery cell becomes excessive (e.g., due to thermal runaway), these features release substances (e.g., gas, liquid, particulate matter, etc.) from the cell to reduce the internal pressure. This prevents excessive internal pressure from causing dangerous accidents such as explosions. For example, these relief features can be explosion-proof valves, explosion-proof discs, and the like.

[0072] For example, as shown in Figures 1 and 2, some electrical devices are powered by batteries. The battery includes a case and a battery cell. The case includes an upper shell and a lower shell. As shown in Figure 3, the battery cell includes an outer shell and an electrode assembly. During the cycle of the battery cell, the electrode assembly will expand repeatedly, and the expansion force acts on the outer shell, causing the outer shell to bulge and deform. Some designs are to set a buffer inside the outer shell to reduce the expansion force on the outer shell by compressing the buffer. However, in order to meet the requirements of battery vacuum baking, the buffer needs to have good anti-deformation performance. In the later stage of battery use, the electrode assembly expands greatly, and the buffer needs to be compressed more to reduce the space occupied by the buffer. That is, the buffer needs to have high compressibility. However, good resistance to vacuum deformation and high compressibility are difficult to be compatible.

[0073] To this end, the present application proposes a buffer component, which has two sides arranged opposite to each other, and the buffer component has a pressure-bearing surface facing or facing away from the electrode assembly, and the pressure-bearing surface is provided with an air-avoiding groove.

[0074] In the buffer component of the above-mentioned structure, by providing an air avoidance groove on the buffer component, the effective area of ​​the buffer component can be reduced, so that the compressibility of the buffer component can be improved on the basis of satisfying good support; by placing the buffer component in the battery cell, during the battery manufacturing process, the buffer component has a strong supporting ability and can meet the requirements of anti-deformation performance in vacuum baking; in the early stage of the battery cell cycle, the buffer component can provide strong supporting ability, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, and alleviate the problem of lithium or sodium precipitation during the cycle; in the late stage of the battery cell cycle, the buffer component can be greatly compressed, reducing the space occupied by the buffer component in the outer shell, ensuring the expandable space of the electrode assembly to a certain extent, reducing the expansion force of the battery cell, and improving the service life of the battery cell.

[0075] The buffer component disclosed in the embodiment of the present application is used for a battery cell. The battery 1000 disclosed in the embodiment of the present application having the battery cell can be used for, but not limited to, an electrical device 2000 such as a vehicle, a ship or an aircraft. The power supply system of the electrical device 2000 composed of the battery 1000 disclosed in the present application can ensure the safety and reliability of the electrical device 2000.

[0076] For example, the power-consuming device 2000 disclosed in the embodiments of the present application may be, but is not limited to, a vehicle, a mobile phone, a tablet, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. A vehicle may be a fuel vehicle, a gas vehicle, a new energy vehicle, or a rail vehicle, and a new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; a spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.; an electric toy includes a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, and an electric airplane toy, etc.; an electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc.

[0077] Hereinafter, a buffer member 200 according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0078] As shown in Figures 4 to 13, the buffer component 200 of the embodiment of the present application is used inside the battery cell 100. The battery cell 100 includes a shell 110 and an electrode assembly 120. The buffer component 200 has a pressure-bearing surface 201 facing or facing away from the electrode assembly 120. The pressure-bearing surface 201 is provided with an air-avoiding groove 202.

[0079] The pressure-bearing surface 201, that is, the surface of the buffer 200 that is squeezed when the electrode assembly 120 expands, can be a surface that directly supports and bears pressure toward the electrode assembly 120, or a surface that indirectly bears pressure toward the back of the electrode assembly 120. For example, the surface of the buffer 200 facing the shell 110 and facing away from the electrode assembly 120, and the surface of the buffer 200 facing the electrode assembly 120 are both pressure-bearing surfaces 201.

[0080] As shown in Figures 4-5, 7-8, and 10-11, a pressure-bearing surface 201 of the buffer 200 has an air avoidance groove 202. Here, the air avoidance groove 202 is provided on one side of the buffer 200, and this side can be in contact with one of the electrode assembly 120 and the outer shell 110, that is, the positioning and fixation of the buffer 200 is achieved, and this side or the other side of the buffer 200 is in contact with the electrode assembly 120, so that the buffer 200 can support the electrode assembly 120. At the same time, this side of the buffer 200 has no contact with the electrode assembly 120 and the outer shell 110 at the position of the air avoidance groove 202.

[0081] That is to say, the air avoidance groove 202 is a space. Through the setting of the air avoidance groove 202, part of the buffer 200 is separated from the shell 110 or the electrode assembly 120, thereby reducing the effective area of ​​the buffer 200. On the basis of ensuring that the buffer 200 has a certain anti-deformation ability, the compressibility of the buffer 200 is improved. Then, during the cyclic charge and discharge process of the battery cell 100, the buffer 200 can be compressed and deformed to alleviate the expansion force of the electrode assembly 120 on the shell 110. At the same time, in the later stage of the cycle, the buffer 200 can have a larger compression amount, reducing the space occupied by the buffer 200 itself, ensuring the expandable space of the electrode assembly 120 to a certain extent, and thus reducing the expansion force of the battery cell 100.

[0082] Therefore, the buffer 200 has strong anti-deformation ability and high compressibility, which can meet the manufacturing requirements of the battery 1000. For example, it can meet the anti-deformation requirements of the buffer 200 in the vacuum baking process, and at the same time meet the full cycle life requirements of the battery cell 100.

[0083] As shown in Figures 6, 9, 12-13, the two pressure-bearing surfaces 201 of the buffer 200 both have an air-avoidance groove 202, that is, the buffer 200 has an air-avoidance groove 202 on both opposite sides. Each side can contact with one of the electrode assembly 120 and the outer shell 110 through the pressure-bearing surface 201, and the other side can also contact with the electrode assembly 120 or the outer shell 110 through the pressure-bearing surface 201. On the basis of achieving the positioning and fixation of the buffer 200, the buffer 200 can support the electrode assembly 120. The buffer 200 has no contact with the electrode assembly 120 and the outer shell 110 at the position of the air-avoidance groove 202, thereby further reducing the effective area of ​​the buffer 200, and improving the compressibility of the buffer 200 while ensuring that the buffer 200 has a certain anti-deformation ability.

[0084] In the buffer member 200 of the above-mentioned structure, by providing an air avoidance groove 202 on the buffer member 200, the effective area of ​​the buffer member 200 can be reduced, so that the buffer member 200 can achieve an improvement in the compressibility of the buffer member 200 on the basis of meeting good support; by placing the buffer member 200 in the battery cell 100, during the manufacturing process of the battery 1000, the buffer member 200 has a strong supporting ability and can meet the requirements of anti-deformation performance in vacuum baking; in the early stage of the cycle of the battery cell 100, the buffer member 200 can provide a strong supporting ability, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, and alleviate the problem of lithium or sodium precipitation during the cycle; in the late stage of the cycle of the battery cell 100, the buffer member 200 can be greatly compressed, reducing the space occupied by the buffer member 200 in the outer shell 110, ensuring the expandable space of the electrode assembly 120 to a certain extent, reducing the expansion force of the battery cell 100, and improving the service life of the battery cell 100.

[0085] As shown in Figures 4 to 6, in some embodiments, the buffer member 200 includes a support plate 10 and a plurality of buffer blocks 20. The buffer blocks 20 are provided on the support plate 10. The plurality of buffer blocks 20 are arranged at intervals, and the gaps between two adjacent buffer blocks 20 are formed as air-avoiding grooves 202.

[0086] As shown in Figures 4 to 6, the support plate 10 is an integral plate-like structure, and the buffer blocks 20 are arranged on the support plate 10. As shown in Figures 4 and 5, multiple buffer blocks 20 are arranged on one side of the support plate 10. As shown in Figure 6, multiple buffer blocks 20 are respectively arranged on opposite sides of the support plate 10. The buffer blocks 20 can contact the outer shell 110 or the electrode assembly 120. The multiple buffer blocks 20 are arranged at intervals, and a gap is formed between two adjacent buffer blocks 20. The gap is the air avoidance groove 202 of the buffer component 200.

[0087] In the above technical solution, the buffer component 200 is set to include multiple buffer blocks 20, and the buffer component 200 as a whole is formed by splicing and combining multiple buffer blocks 20 with the support plate 10. Each buffer block 20 has a simple structure and a simple manufacturing process, which is convenient for manufacturing and forming.

[0088] In some embodiments, the buffer block 20 is fixedly connected to the support plate 10 .

[0089] The entire buffer component 200 is assembled by fixedly connecting the buffer block 20 to the support plate 10 . The connection methods include bonding, plugging, etc., thereby improving the stability of the buffer component 200 .

[0090] In some embodiments, the buffer block 20 is bonded to the support plate 10, and multiple buffer blocks 20 can be directly bonded to the support plate 10 to achieve the combined assembly of the buffer component 200. The assembly process is simple and easy to assemble and form, which reduces the manufacturing difficulty of the entire buffer component 200 and reduces the manufacturing cost.

[0091] As shown in FIG. 4 to FIG. 6 , in some examples, a plurality of buffer blocks 20 on one side of the support plate 10 are arranged at intervals along the length direction and / or the width direction of the support plate 10 .

[0092] As shown in Figures 4 and 5, the front side of the support plate 10 has multiple buffer blocks 20, and the multiple buffer blocks 20 can be arranged at intervals along the length direction of the support plate 10 (the left and right direction as shown in Figure 4), and each buffer block 20 can extend along the width direction of the support plate 10, so that the buffer blocks 20 are evenly arranged on the support plate 10. Multiple buffer blocks 20 can be arranged at intervals along the width direction of the support plate 10 (the up and down direction as shown in Figure 4), and each buffer block 20 can extend along the length direction of the support plate 10, so that the buffer blocks 20 are evenly arranged on the support plate 10. Of course, the buffer blocks 20 can also be arranged in multiple rows and columns, thereby making the arrangement of the buffer blocks 20 more uniform, and thus making the support of the buffer member 200 to the electrode assembly 120 more uniform, and the compression deformation can also be more uniform, thereby effectively alleviating the expansion force of the battery cell 100.

[0093] As shown in FIG. 5 , in some embodiments, the distance L1 between two adjacent buffer blocks 20 is no greater than 20 mm.

[0094] As shown in FIG5 , two adjacent buffer blocks 20 are spaced apart in the left-right direction, and the distance between the two adjacent buffer blocks 20 is L1. Of course, if the two adjacent buffer blocks 20 are spaced apart in the up-down direction, the distance between the two adjacent buffer blocks 20 is still defined as L1. If L1 is too large, that is, the distance between the two adjacent buffer blocks 20 is too large, it will lead to uneven local stress and easily cause the space of the air-avoidance groove 202 to be too large. The contact surface between the buffer 200 and the electrode assembly 120 or the shell 110 is too small, which makes it difficult to play an effective supporting effect. This limits L1 to a range of no more than 20mm, that is, L1 can be 20mm, or any value less than 20mm, for example, L1 is 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, etc., thereby avoiding the problem of uneven local stress caused by the large distance between the two buffer blocks 20, and improving the supporting effect of the buffer component 200.

[0095] In addition, if L1 is too small, the space of the air avoidance groove 202 is too small, and it is difficult to effectively improve the compression rate of the buffer 200. In some preferred examples, 5mm≤L1≤10mm. For example, L1 can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc., thereby making the buffer 200 have better support and improving the compressibility of the buffer 200.

[0096] As shown in FIG. 5 and FIG. 6 , in some embodiments, the thickness of the support plate 10 ranges from 30 μm to 200 μm.

[0097] As shown in Figures 5 and 6, if the thickness of the support plate 10 is too large, it is easy to cause the buffer 200 to be too thick, and the buffer 200 occupies too much space, affecting the energy density of the battery cell 100. At the same time, if the support plate 10 is too thick, the hardness of the buffer 200 will increase, and the buffer 200 will be difficult to achieve a large compression. If the thickness of the support plate 10 is too small, it is easy to cause the supporting strength of the buffer 200 to be too low, and the fixing reliability of the buffer block 20 is poor. For this reason, the thickness of the support plate 10 can be limited to 30um-200um. The thickness of the support plate 10 can be 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 200um.

[0098] In this way, it is possible to avoid to a certain extent the problem that the buffer 200 is too thick, resulting in the buffer 200 occupying too much space and the buffer 200 being difficult to compress, and it is also possible to improve the support effect on the buffer block 20 and the support capacity of the buffer 200, thereby meeting the requirements for anti-deformation performance during vacuum baking; or during the cycle of the battery cell 100, the buffer 200 can provide stronger support capacity and reduce pole piece deformation.

[0099] In some embodiments, the compressibility of the support plate 10 at 1 MPa is less than 5%.

[0100] The compression rate of the support plate 10 at 1 MPa is less than 5%, that is, the compression rate of the support plate 10 at 1 MPa is 5%, or less than 5%, such as 4%, 3%, 2%, 1%, or may be 0.

[0101] In the above technical solution, by limiting the compression rate of the support plate 10 to within 5%, the support plate 10 can achieve a reliable supporting effect on the buffer block 20, thereby improving the support performance of the buffer member 200.

[0102] In some embodiments, the material of the support plate 10 includes at least one of high-density polyethylene, polymethacrylate, polyethylene terephthalate, and polytetrafluoroethylene.

[0103] The support plate 10 can be high-density polyethylene, polymethacrylate, polyethylene terephthalate, polytetrafluoroethylene, or a composite material. It can also be formed by compounding other materials. By adopting the above materials, the support plate 10 can achieve a reliable supporting effect on the buffer block 20, thereby improving the support performance of the buffer component 200.

[0104] As shown in FIG. 7 to FIG. 13 , in some embodiments, the buffer member 200 is a buffer block 20 , and a portion of the outer surface of the buffer block 20 is recessed inward to form a groove 21 , and the groove 21 is formed as a void-avoiding groove 202 .

[0105] As shown in Figures 7 to 13, the buffer block 20 is a block structure. The buffer block 20 forms a buffer part 200 as a whole. The outer surface of the buffer block 20 has an inwardly recessed groove 21, and the groove 21 is formed as an air-avoiding groove 202. The portion of the buffer block 20 where the groove 21 is not formed can contact the electrode assembly 120 or the outer shell 110, and the bottom of the groove 21 is spaced apart from the electrode assembly 120 or the outer shell 110. That is, the buffer part 200 is an integral structural part, and the air-avoiding groove 202 is formed by digging grooves. As shown in Figures 7 and 10, the outer surface of one side of the buffer block 20 has an inwardly recessed groove 21, and as shown in Figure 12, the outer surfaces of the opposite sides of the buffer block 20 respectively have inwardly recessed grooves 21.

[0106] It can be understood that the buffer block 20 is formed in a sheet shape, wherein the buffer block 20 can be formed in a square sheet shape, a round sheet shape, or a triangular sheet shape. By setting it as a sheet structure, the buffer component 200 is easily installed in the battery cell 100, while minimizing the space occupied by the buffer component 200.

[0107] In the above technical solution, the buffer component 200 is designed as an integral structural component and the air-avoiding groove 202 is formed by digging a groove, which facilitates manufacturing. At the same time, it can reduce the assembly steps of the buffer component 200, reduce the assembly workload, and reduce manufacturing costs.

[0108] As shown in FIG. 7 to FIG. 13 , in some embodiments, the groove 21 includes a plurality of grooves 21 , and the plurality of grooves 21 are arranged at intervals along the length direction of the buffer 200 and / or the width direction of the buffer 200 .

[0109] As shown in Figure 8, the buffer block 20 has a plurality of grooves 21 on the front side, and the plurality of grooves 21 can be arranged at intervals along the length direction of the buffer block 20 (the left-right direction as shown in Figure 8), and each groove 21 can extend along the width direction of the buffer block 20, so that the grooves 21 are evenly arranged on the buffer block 20. The plurality of grooves 21 can be arranged at intervals along the width direction of the buffer block 20 (the up-down direction as shown in Figure 9), and each groove 21 can extend along the length direction of the buffer block 20, so that the grooves 21 are evenly arranged on the buffer block 20. Of course, the grooves 21 can also be arranged in multiple rows and columns, thereby making the arrangement of the grooves 21 more uniform, thereby making the buffer member 200 support the electrode assembly 120 more uniform, and the compression deformation can also be more uniform, thereby effectively alleviating the expansion force of the battery cell 100.

[0110] As shown in FIG8 , in some embodiments, the dimension of each groove 21 in the length direction of the buffer 200 is L2, and the dimension of each groove 21 in the width direction of the buffer 200 is L3, wherein L2 is not greater than 20 mm, and L3 is not greater than 20 mm.

[0111] As shown in Figure 8, if the length or width of the groove 21 is too large, it will cause local uneven stress and easily cause the space of the air avoidance groove 202 to be too large, making it difficult to play an effective supporting effect. For this reason, L2 and L3 are limited to a range of no more than 20mm, that is, L2 and L3 can be 20mm, or any value less than 20mm, for example, L1 is 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, etc., among which the values ​​of L2 and L3 can be the same or different, thereby avoiding the problem of local uneven stress caused by the distance between the two buffer blocks 20 being too large, and improving the supporting effect of the buffer component 200.

[0112] In addition, if L2 and L3 are too small, the space of the air avoidance groove 202 is too small, and it is difficult to effectively improve the compression rate of the buffer 200. In some preferred examples, 5mm≤L2≤10mm, 5mm≤L3≤10mm. For example, L2 and L3 can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc., thereby making the buffer 200 have better support and improving the compressibility of the buffer 200.

[0113] As shown in FIG. 10 to FIG. 13 , in some embodiments, the groove 21 is formed to extend along the length direction of the buffer 200 or the width direction of the buffer 200 to form a strip-shaped groove 21 .

[0114] As shown in Figures 10 to 13, the groove 21 forms a long strip groove 21, and either end of the groove 21 can have an open mouth, wherein the strip groove 21 can extend along the length direction of the buffer 200, and can also extend along the width direction of the buffer 200. This allows the buffer 200 to have better support and higher compressibility, thereby reducing the number of grooves 21, simplifying the structure of the buffer 200, and facilitating the manufacturing and molding of the buffer 200.

[0115] In some embodiments, the buffer block 20 is a piece of porous material.

[0116] The porous material can be made through a foaming process. By using such a porous foam material, the compressibility of the buffer pad 200 can be improved while reducing the manufacturing cost.

[0117] In some embodiments, the material of the buffer block 20 includes at least one of polyethylene, polypropylene, polyurethane, and silicone rubber.

[0118] The buffer 20 can be made of any one of polyethylene, polypropylene, polyurethane, silicone rubber, or a composite material. In the above technical solution, by using such materials, the compressibility of the buffer 200 can be improved while reducing the manufacturing cost.

[0119] As shown in FIG. 6 and FIG. 12 - FIG. 13 , in some embodiments, air-avoiding grooves 202 are respectively provided on opposite sides of the buffer 200 in the thickness direction, and the air-avoiding grooves 202 are arranged opposite to each other in the thickness direction of the buffer 200 .

[0120] As shown in Figure 6, buffer blocks 20 are respectively provided on the front and rear sides of the support plate 10, and the buffer blocks 20 correspond in position in the front-to-back direction. As shown in Figures 12 and 13, grooves 21 are respectively formed on the front and rear sides of the buffer block 20, and the grooves 21 correspond in position in the front-to-back direction, thereby making the positions of the air-avoidance grooves 202 on both sides of the buffer member 200 correspond. Therefore, when the electrode assembly 120 expands, the buffer member 200 can be prevented from being deformed in its length or width direction, thereby improving the stability of the buffer member 200 and further improving the reliability of the support of the buffer member 200.

[0121] As shown in FIG. 4 to FIG. 13 , in some embodiments, the area of ​​the pressure-bearing surface 201 of the buffer 200 is S1 , and the area of ​​the air-avoiding groove 202 is S2 , wherein the range of S2 / S1 is 0-70%.

[0122] As shown in Figures 4 to 13, the area of ​​the pressure-bearing surface 201 of the buffer 200 provided with the air-avoidance groove 202 is S1, which refers to the area of ​​the entire buffer 200, that is, the area of ​​the internal area enclosed by the edge of the buffer 200, and the area of ​​the air-avoidance groove 202 is S2. As shown in Figure 4, S2 is the cross-sectional area of ​​the gaps between the multiple buffer blocks 20. As shown in Figure 7, S2 is the cross-sectional area of ​​the multiple grooves 21. If the area occupied by the air-avoidance groove 202 is too large, it is easy to cause the contact surface between the buffer 200 and the electrode assembly 120 or the shell 110 to be too small, making it difficult to play an effective supporting effect. For this reason, the range of S2 / S1 can be limited to 0-70%. S2 / S1 can be any value between 0-70%, for example, S2 / S1 is 10%, 20%, 30%, 40%, 50%, 60%, 70%, etc.

[0123] This can reduce the effective area of ​​the buffer 200 and improve the compressibility of the buffer 200, so that the buffer 200 has both good anti-deformation ability and high compressibility, thereby reducing the expansion force of the battery cell 100 in the later stage.

[0124] As shown in FIG. 4 to FIG. 13 , in some embodiments, S2 / S1 ranges from 20% to 50%.

[0125] If the area occupied by the air-avoidance groove 202 is too small and the space of the air-avoidance groove 202 is too small, it is difficult to effectively improve the compression rate of the buffer 200. In some preferred examples, the range of S2 / S1 is 20%-50%, that is, S2 / S1 can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, thereby further enabling the buffer 200 to have both good anti-deformation ability and high compressibility, thereby reducing the later expansion force of the battery cell 100.

[0126] As shown in FIG. 5 and FIG. 8 , in some embodiments, the thickness of the buffer 200 is H1 , the dimension of the air-avoiding groove 202 in the thickness direction of the buffer 200 is H2 , and the range of H2 / H1 is 0-90%.

[0127] As shown in Figures 5 and 8 , if the clearance groove 202 occupies too much thickness, the buffer 200 may be easily compressed and deformed, making it difficult for the buffer 200 to provide effective support. Therefore, H2 / H1 is limited to 0-90%. H2 / H1 can be any value between 0-90%, for example, H2 / H1 is 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc. This allows the buffer 200 to have both good deformation resistance and high compressibility, thereby reducing the subsequent expansion force of the battery cell 100.

[0128] In some preferred embodiments, H2 / H1 ranges from 30-85%.

[0129] If the thickness occupied by the air-avoidance groove 202 is too small, it is difficult to effectively improve the compression rate of the buffer 200. In some preferred examples, the range of H2 / H1 is 30%-85%, that is, H2 / H1 can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc., thereby further enabling the buffer 200 to have both good anti-deformation ability and high compressibility, thereby reducing the later expansion force of the battery cell 100.

[0130] Furthermore, H2 / H1 is preferably 50%-80%, that is, H2 / H1 can be any value between 50%-80%, for example, it can be 50%, 53%, 62%, 67%, 73%, 78%, 80%, etc.

[0131] In some embodiments, the compressibility of the buffer member 200 at 1 MPa is not less than 60%.

[0132] The compressibility of a buffer 200 is the ratio of the reduced thickness of the buffer 200 when compressed to its free thickness. The compressibility of the buffer 200 can be measured using a vernier caliper. Specifically, the free thickness d1 of the buffer 200 is measured at least three times, and the average value is taken. The buffer 200 is placed between two parallel metal plates and a specific pressure is applied and maintained for one minute. The thickness d2 of the buffer 200 is then measured using a vernier caliper, and the average value is taken at least three times. The compressibility of the buffer 200 is calculated as follows: Compressibility of the buffer 200 (%) = (d2 - d1) / d1 × 100%.

[0133] If the compression rate of the buffer 200 is too small, the compressible amount of the buffer 200 is small, and it is difficult to absorb the deformation of the electrode assembly 120, especially in the later stage of the battery cell 100 cycle, the buffer 200 is difficult to compress, resulting in insufficient expansion space for the electrode assembly 120, which in turn affects the later expansion force of the battery cell 100. For this reason, the compression rate of the buffer 200 at 1 MPa is set to be no less than 60%, which can be 60%, or 70%, or 80%. In this way, the buffer 200 can be compressed and deformed as the electrode assembly 120 expands, so as to absorb the expansion of the electrode assembly 120 as much as possible and reduce the expansion force of the battery cell 100 in the later stage of the cycle.

[0134] In some examples, the compression rate of the buffer member 200 under the application of the first pressure is 60%-90%, the range of the first pressure is 0.8MPa-1.2MPa, and the first pressure can be 0.8MPa, 0.9MPa, 1.0MPa, 1.1MPa, or 1.2MPa; further, when the buffer pad 200 per unit area is subjected to the first pressure, the compression rate of the buffer pad 200 is 70%-90%.

[0135] As shown in FIG. 14 to FIG. 16 , in a second aspect, the present application proposes a battery cell 100 , including a housing 110 , an electrode assembly 120 and a buffer 200 , wherein the buffer 200 and the electrode assembly 120 are both disposed within the housing 110 .

[0136] The outer shell 110 refers to the outermost structural component of the battery cell 100. The outer shell 110 accommodates the electrode assembly 120 and the electrolyte, etc. Here, the outer shell 110 can be an aluminum shell.

[0137] The electrode assembly 120 is arranged in the outer shell 110. The electrode assembly 120 can be a laminated type, that is, multiple electrode sheets of the electrode assembly 120 are stacked, or the electrode assembly 120 can be a wound type, that is, the positive electrode sheet and the negative electrode sheet of the electrode assembly 120 are stacked and then wound into shape; in addition, there can be one electrode assembly 120 in the outer shell 110, or there can be multiple electrode assemblies 120.

[0138] The buffer member 200 is the buffer member 200 proposed in the first aspect of this application. The buffer member 200 is arranged in the shell 110, that is, the buffer member 200 is located inside a battery cell 100. The buffer member 200 can be located between the shell 110 and the electrode assembly 120, or between adjacent electrode assemblies 120.

[0139] The buffer member 200 is provided with an air avoidance groove 202, so that part of the buffer member 200 is separated from the shell 110 or the electrode assembly 120, thereby reducing the effective area of ​​the buffer member 200. On the basis of ensuring that the buffer member 200 has a certain anti-deformation ability, the compressibility of the buffer member 200 is improved, so that the buffer member 200 has a strong anti-deformation ability and a high compressibility, which can meet the manufacturing requirements of the battery 1000. For example, it can meet the deformation resistance requirements of the buffer member 200 in the vacuum baking process, and at the same time meet the full cycle life requirements of the battery cell 100.

[0140] When the battery cell 100 is charged and discharged and the electrode assembly 120 expands and deforms, the electrode assembly 120 compresses the buffer 200 when it expands, causing the buffer 200 to be compressed and deformed. The space occupied by the buffer 200 is reduced, thereby increasing the space in the shell 110 for accommodating the electrode assembly 120. The expanded part of the electrode assembly 120 can occupy this part of the space, thereby reducing the stress on the electrode assembly 120 when it expands, and at the same time reducing the deformation of the shell 110 as much as possible, avoiding the problem of excessive deformation of the shell 110 causing damage to the battery 1000 or electrical devices and a short service life.

[0141] At the same time, in the later stage of the cycle, the buffer 200 can have a larger compression amount, further reducing the space occupied by the buffer 200 itself, ensuring the expandable space of the electrode assembly 120 to a certain extent, and thus reducing the expansion force of the battery cell 100.

[0142] In the battery cell 100 of the above-mentioned structure, by adopting the above-mentioned buffer part 200, during the manufacturing process of the battery 1000, the buffer part 200 has a strong supporting ability and can meet the requirements of anti-deformation performance during vacuum baking; in the early stage of the cycle of the battery cell 100, the buffer part 200 can provide a strong supporting ability, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, and alleviate the problem of lithium or sodium precipitation during the cycle; in the late stage of the cycle of the battery cell 100, the buffer part 200 can be greatly compressed, reducing the space occupied by the buffer part 200 in the outer shell 110, ensuring the expandable space of the electrode assembly 120 to a certain extent, reducing the expansion force of the battery cell 100, and improving the service life of the battery cell 100.

[0143] As shown in FIG. 14 , in some embodiments, a buffer member 200 is provided between the housing 110 and the electrode assembly 120 .

[0144] By arranging the buffer part 200 in the outer shell 110 and the electrode assembly 120, the electrode assembly 120 can be effectively supported, and the requirements for anti-deformation performance during vacuum baking can be met, while reducing the deformation of the electrode piece; in addition, when the battery cell 100 is charged and discharged, as the electrode assembly 120 expands, the buffer part 200 is compressed and deformed, thereby increasing the space inside the battery cell 100 to accommodate the electrode assembly 120, thereby reducing the stress on the electrode assembly 120 caused by expansion, and effectively reducing the probability of deformation of the outer shell 110, thereby alleviating the problem of large expansion force of the battery cell 100 in the later stage of the cycle and extending the service life of the battery cell 100.

[0145] In the above technical solution, the buffer member 200 is arranged between the housing 110 and the electrode assembly 120, which is easy to install and can reduce the stress on the housing 110 when the electrode assembly 120 expands, effectively reducing the probability of deformation of the housing 110.

[0146] As shown in FIG. 15 and FIG. 16 , in some embodiments, the battery cell 100 includes a plurality of electrode assemblies 120 , and the buffer 200 is disposed between two adjacent electrode assemblies 120 .

[0147] As shown in Figures 15 and 16, a buffer member 200 is provided between adjacent electrode assemblies 120. For example, the buffer member 200 can be provided between any two adjacent electrode assemblies 120, or between two partially adjacent electrode assemblies 120. Thus, the number of buffer members 200 can be one or more.

[0148] In the above technical solution, by arranging the buffer member 200 between the electrode assemblies 120 , the buffer member 200 can effectively absorb the expansion of the electrode assembly 120 and reduce the stress on the housing 110 when the electrode assembly 120 expands.

[0149] As shown in FIG16 , a plurality of buffer members 200 are provided in the battery cell 100, at least one buffer member 200 is provided between the outer shell 110 and the electrode assembly 120, and at least one buffer member 200 is provided between two adjacent electrode assemblies 120. Thus, by providing a plurality of buffer members 200 at different positions, the expansion of the electrode assembly 120 can be effectively absorbed, and the stress on the outer shell 110 when the electrode assembly 120 expands can be reduced.

[0150] In some embodiments, the group margin of the battery cells 100 ranges from 96% to 105%.

[0151] The outer shell 110 has two inner wall surfaces arranged opposite to each other, and the two inner wall surfaces are located on both sides of the arrangement direction of the buffer 200 and the electrode assembly 120, such as the inner wall surfaces in the front-to-back direction as shown in Figure 14. The group margin of the battery cell 100 is the ratio of the sum of the thickness of the electrode assembly 120 and the total free thickness of the buffer 200 to the distance between the two opposite inner wall surfaces of the outer shell 110. Here, the thickness of the electrode assembly 120 is the thickness in the fully charged state. By adopting the above-mentioned buffer 200, the group margin of the battery cell 100 is between 96% and 105%, that is, in the thickness direction of the battery cell 100, the buffer 200 and the electrode assembly 120 can roughly fill the entire inner cavity of the outer shell 110, thereby ensuring to a certain extent that the buffer 200 can effectively support the electrode assembly 120, reducing the interface abnormality problems such as wrinkling of the electrode sheet caused by the failure of the buffer 200 to support the electrode assembly 120.

[0152] Preferably, the group margin range of the battery cell 100 is 98%-103%, which can further improve the support of the buffer 200 for the electrode assembly 120, especially reduce the interface abnormality problems such as wrinkling of the electrode sheet caused by the failure of the buffer 200 to support the electrode assembly 120 in the fully discharged state.

[0153] In some embodiments, the ratio of the thickness of the buffer member 200 to the thickness of the electrode assembly 120 is in a range of 2% to 15%.

[0154] Here, the thickness of the buffer 200 is the thickness of the buffer 200 in the free state, and the thickness of the electrode assembly 120 is the thickness of the electrode assembly 120 in the fully charged state. If the thickness of the buffer 200 is too much, it is easy to affect the energy density of the battery cell 100. If the thickness of the buffer 200 is too little, it is difficult to play an effective buffering role, which will cause the shell 110 to be subjected to excessive expansion force, especially in the late cycle of the battery cell 100, the compression of the buffer 200 is limited, resulting in excessive expansion force. For this reason, the buffer 200 is compressed to a certain extent. The ratio of the thickness of 200 to the thickness of the electrode assembly 120 is limited to between 2% and 15%. The ratio of the thickness of the buffer 200 to the thickness of the electrode assembly 120 can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%. This can not only improve the energy density of the battery cell 100, but also enable the buffer 200 to play an effective buffering role, reduce the expansion force on the outer shell 110 when the electrode assembly 120 expands, and effectively reduce the probability of deformation of the outer shell 110.

[0155] Preferably, the ratio of the thickness of the buffer 200 to the thickness of the electrode assembly 120 is 5%-10%, that is, the ratio of the thickness of the buffer 200 to the thickness of the electrode assembly 120 can be 5%, 5.5%, 6.5%, 7.5%, 8.5%, 9.1%, 9.5%, 10%, etc., thereby further improving the energy density of the battery cell 100, and enabling the buffer 200 to play an effective buffering role, reducing the expansion force on the outer shell 110 when the electrode assembly 120 expands, and effectively reducing the probability of deformation of the outer shell 110.

[0156] In the embodiment of the present application, the buffer member 200 can be flexibly positioned relative to the electrode assembly 120 according to the structure of the electrode assembly 120 .

[0157] As shown in Figures 3 and 14-16, in some embodiments, the electrode assembly 120 includes a plurality of pole pieces arranged in a wound manner, and the outer peripheral surface of the electrode assembly 120 includes a straight portion 121 and a bend portion 122 connected to the end of the straight portion 121, and at least one of the straight portion 121 and the bend portion 122 is arranged opposite to the buffer member.

[0158] A plurality of electrode sheets arranged in a wound manner, i.e., a positive electrode sheet 1201 and a negative electrode sheet 1202 are stacked and wound around a set axis to form an electrode assembly 120. The straight portion 121 refers to the portion of the electrode sheet extending along the plane when wound; the turning portion 122 refers to the portion of the electrode sheet extending along the arc surface when wound. For example, as shown in FIG3 , the front side surface and the rear side surface of the electrode assembly 120 are formed as a straight portion 121, and the left and right ends of the front side surface and the rear side surface are the turning portions 122, or the left side surface and the right side surface can also be formed as the turning portion 122 as a whole.

[0159] The straight portion 121 is arranged opposite to the buffer member 200, so that the buffer member 200 can play a buffering role on the area of ​​the electrode assembly 120 corresponding to the straight portion 121; the bend portion 122 is arranged opposite to the buffer member 200, so that the area of ​​the buffer member 200 facing the bend portion 122 is roughly formed into an arc shape, so that the buffer member 200 can buffer the expansion force of the bend portion 122 and reduce the risk of bridge breakage and lithium deposition of the electrode assembly 120.

[0160] As shown in Figures 14 to 17, in some embodiments, the electrode assembly 120 includes a plurality of positive electrode sheets 1201 and a plurality of negative electrode sheets 1202 stacked along a first direction, and the buffer member 200 is arranged opposite to the surface of at least one side of the electrode assembly 120 along the first direction.

[0161] The first direction here is the front-to-back direction shown in Figure 17. All the positive pole sheets 1201 and all the negative pole sheets 1201 of the electrode assembly 120 are stacked, and the positive pole sheets 1201 and the negative pole sheets 1202 both extend along a plane perpendicular to the first direction. The electrode assembly 120 of the above structure will expand in the first direction during use. Therefore, the buffer 200 is arranged relative to the surface of at least one side of the electrode assembly 20 along the first direction, so that the buffer 200 can more fully provide buffering and support to the pole sheets, reduce wrinkling of the pole sheets, etc., so that the buffer 200 plays an effective buffering and supporting role, and the area required for the buffer 200 is small and the cost is low.

[0162] In some embodiments, the opening of the air-avoiding groove 202 is formed on the pressure-bearing surface 201 , and the electrode stacking direction of the region of the electrode assembly 120 facing the pressure-bearing surface 201 is perpendicular to the pressure-bearing surface 201 .

[0163] Here, in the area of ​​the electrode assembly 120 opposite to the pressure-bearing surface 201, for example, in the area corresponding to the straight portion 121 in the wound electrode assembly 120, the stacking direction of the positive electrode sheets 1201 and the negative electrode sheets 1202 is perpendicular to the pressure-bearing surface 201; for another example, in the laminated electrode assembly 20, multiple positive electrode sheets 1201 and multiple negative electrode sheets 1202 are stacked along a first direction (such as the front-to-back direction shown in Figure 17), and the pressure-bearing surface 201 is perpendicular to the first direction.

[0164] During use, the electrode is more likely to expand along the stacking direction. The stacking direction of the electrode in the area opposite to the pressure-bearing surface 201 is perpendicular to the pressure-bearing surface 201, so that the pressure-bearing surface 201 can more fully provide cushioning and support to the electrode, thereby improving the effect of reducing electrode wrinkling.

[0165] As shown in FIG. 3 and FIG. 14 - FIG. 16 , in some embodiments, the buffer member 200 corresponds to at least the largest surface of the electrode assembly 120 .

[0166] As shown in Figures 3 and 14-16, some electrode assemblies 120 have two end faces and four side surfaces, of which the areas of the two oppositely arranged side surfaces are relatively large, namely the large faces of the electrode assembly 120, and the areas of the other two oppositely arranged side surfaces are relatively small, namely the small faces of the electrode assembly 120. The buffer 200 corresponds to the large face, or both the large face and the small face have corresponding buffers 200, or one end face and the large face have corresponding buffers 200, or both the end faces and the large face have corresponding buffers 200. The buffer 200 corresponds to the large face, so that it can effectively support the electrode assembly 120 and reduce the wrinkling phenomenon of the electrode piece. At the same time, when the electrode assembly 120 expands, the expansion of the large face will be relatively large. Therefore, by placing the buffer 200 opposite to the large face of the electrode assembly 120, the expansion of the large face can be absorbed as much as possible, thereby reducing the stress on the electrode assembly 120 caused by the expansion.

[0167] In addition, the buffer member 200 may be disposed continuously, and disposed between any adjacent electrode assemblies 120 by folding or winding.

[0168] The battery 1000 according to the third embodiment of the present application includes the battery cell 100 according to the second embodiment of the present application.

[0169] According to the fourth embodiment of the present application, the power device 2000 includes the battery 1000 according to the third embodiment of the present application, and the battery 1000 is used to provide power to the power device 2000. Therefore, by using the above-mentioned battery 1000, the safety and reliability of the power device 2000 are improved.

[0170] Optionally, as shown in FIG1 , when battery 1000 is used in a vehicle, it can be located at the bottom, front, or rear of the vehicle. Battery 1000 can be used to power the vehicle, for example, as an operating power source for the vehicle. The vehicle can also include a controller and a motor, with the controller controlling battery 1000 to power the motor, for example, to meet the vehicle's starting, navigation, and operating power requirements during driving.

[0171] A battery 1000 and a vehicle having the same according to a specific embodiment of the present application will be described below with reference to the accompanying drawings.

[0172] As shown in Figure 1, the battery 1000 is arranged at the bottom of the vehicle, and as shown in Figures 4, 5 and 14, the battery 1000 includes a plurality of battery cells 100, each battery cell 100 includes an outer shell 110, an electrode assembly 120 and a buffer 200, the outer shell 110 includes a shell 111 and an end cover 112, and the electrode assembly 120 and the buffer 200 are arranged in the outer shell 110.

[0173] The buffer component 200 includes a support plate 10 and a plurality of buffer blocks 20. The plurality of buffer blocks 20 are bonded to one side surface of the support plate 10, and the plurality of buffer blocks 20 are arranged at equal intervals, wherein the space between two adjacent buffer blocks 20 forms an air avoidance groove 202. The buffer component 200 is installed between the outer shell 110 and the electrode assembly 120. The buffer block 20 can abut against the electrode assembly 120. The setting of the air avoidance groove 202 makes the support plate 10 and the electrode assembly 120 arranged at intervals, and the other side of the support plate 10 abuts against the outer shell 110.

[0174] By setting the air-avoidance groove 202, part of the buffer 200 is separated from the shell 110 or the electrode assembly 120, thereby reducing the effective area of ​​the buffer 200. On the basis of ensuring that the buffer 200 has a certain anti-deformation ability, the compressibility of the buffer 200 is improved. Then, during the cyclic charge and discharge process of the battery cell 100, the buffer 200 can relieve the expansion force of the electrode assembly 120 on the shell 110 through compression deformation. At the same time, in the later stage of the cycle, the buffer 200 can have a larger compression amount, reducing the space occupied by the buffer 200 itself, ensuring the expandable space of the electrode assembly 120 to a certain extent, and thus reducing the expansion force of the battery cell 100.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A buffer member used inside a battery cell, wherein the battery cell includes an electrode assembly, wherein: The buffer member has a pressure-bearing surface facing toward or facing away from the electrode assembly, and the pressure-bearing surface is provided with a void-avoiding groove.

2. The buffer member according to claim 1, wherein: The buffer member includes a support plate and a plurality of buffer blocks, wherein the buffer blocks are arranged on the support plate, the plurality of buffer blocks are arranged at intervals, and a gap between two adjacent buffer blocks forms the air-avoiding groove.

3. The buffer member according to claim 2, wherein: The buffer block is fixedly connected to the support plate.

4. The buffer member according to claim 2, wherein: The plurality of buffer blocks on one side of the support plate are arranged at intervals along the length direction and / or the width direction of the support plate.

5. The buffer member according to claim 4, wherein: The distance L1 between two adjacent buffer blocks is not greater than 20 mm.

6. The buffer member according to claim 2, wherein: The thickness of the support plate ranges from 30um to 200um.

7. The buffer member according to claim 2, wherein: The compression rate of the support plate at 1 MPa is not greater than 5%.

8. The buffer member according to claim 2, wherein: The material of the support plate includes at least one of high-density polyethylene, polymethacrylate, polyethylene terephthalate, and polytetrafluoroethylene.

9. The buffer member according to claim 1, wherein: The buffer member is a buffer block, a portion of the outer surface of the buffer block is recessed inward to form a groove, and the groove is formed as the air avoidance groove.

10. The buffer member according to claim 9, wherein: The grooves include a plurality of grooves, and the plurality of grooves are arranged at intervals along the length direction of the buffer member and / or the width direction of the buffer member.

11. The buffer member according to claim 10, wherein: The dimension of each of the grooves in the length direction of the buffer is L2, and the dimension of each of the grooves in the width direction of the buffer is L3, wherein L2 is not greater than 20 mm, and L3 is not greater than 20 mm.

12. The buffer member according to claim 9, wherein: The groove is formed to extend along the length direction of the buffer member or the width direction of the buffer member to form a strip-shaped groove.

13. The buffer according to any one of claims 2 to 12, wherein: The material of the buffer block includes at least one of polyethylene, polypropylene, polyurethane and silicone rubber.

14. The buffer according to any one of claims 1 to 13, wherein: The avoidance grooves are respectively disposed on opposite sides of the buffer member in the thickness direction, and the avoidance grooves are arranged opposite to each other in the thickness direction of the buffer member.

15. The buffer according to any one of claims 1 to 14, wherein: The area of ​​the pressure-bearing surface of the buffer is S1, and the area of ​​the air-avoiding groove is S2, wherein the range of S2 / S1 is 0-70%.

16. The buffer member according to claim 15, wherein: The range of S2 / S1 is 20%-50%.

17. The buffer according to any one of claims 1 to 16, wherein: The thickness of the buffer is H1, the dimension of the air-avoiding groove in the thickness direction of the buffer is H2, and the range of H2 / H1 is 0-90%.

18. The buffer member according to claim 17, wherein: The range of H2 / H1 is 30-85%.

19. The buffer according to any one of claims 1 to 18, wherein: The compression rate of the buffer component at 1 MPa is greater than 60%.

20. A battery cell, wherein: The invention comprises a shell, an electrode assembly and the buffer member according to any one of claims 1 to 19, wherein the buffer member and the electrode assembly are both arranged in the shell.

21. The battery cell according to claim 20, wherein: The buffer member is arranged between the housing and the electrode assembly.

22. The battery cell according to any one of claims 20 to 21, wherein: The battery cell includes a plurality of electrode assemblies, and the buffer is arranged between two adjacent electrode assemblies.

23. The battery cell according to any one of claims 20 to 22, wherein: The group margin of the battery cells ranges from 96% to 105%.

24. The battery cell according to any one of claims 20 to 23, wherein: The ratio of the thickness of the buffer member to the thickness of the electrode assembly is in a range of 2% to 15%.

25. The battery cell according to any one of claims 20 to 24, wherein: The electrode assembly comprises a plurality of electrode sheets arranged in a winding manner, and the outer peripheral surface of the electrode assembly comprises a straight portion and a bend portion connected to the end of the straight portion, and at least one of the straight portion and the bend portion is arranged opposite to the buffer; or, The electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked along a first direction, and the buffer is disposed opposite to a surface of at least one side of the electrode assembly along the first direction.

26. The battery cell according to any one of claims 20 to 25, wherein: The notch of the air-avoiding groove is formed on the pressure-bearing surface, and the stacking direction of the pole pieces in the area where the electrode assembly faces the pressure-bearing surface is perpendicular to the pressure-bearing surface.

27. A battery, wherein: Comprising a battery cell according to any one of claims 20-26.

28. An electrical device, wherein: A battery according to claim 27, for providing electrical energy.

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