Cushion pad, battery monomer, battery and electric device

Abstract

A cushion pad (200), a battery cell (100), a battery (1000), and an electric device (2000), the cushion pad (200) being used inside the battery cell (100), the cushion pad (200) comprising: a plurality of cushion members (20), the plurality of cushion members (20) being arranged along a first direction, two adjacent cushion members (20) having different rebound rates after applying the same pressure.

Description

Buffer pad, battery cell, battery and electrical device Technical Field

[0001] The present application relates to the field of batteries, and in particular to a buffer pad, 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 pad, 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 pad for use inside a battery cell, comprising: a plurality of buffer members arranged along a first direction, and two adjacent buffer members having different rebound rates after the same pressure is applied.

[0007] In the technical solution of the embodiment of the present application, by adopting multiple buffer parts with different rebound rates, the buffer pad can have both high rebound elasticity and good support, so as to play a supporting role in the entire cycle of charge and discharge of the battery cell and meet the use requirements of the battery cell. At the same time, when the electrode assembly expands, the buffer pad can be compressed and deformed to alleviate the expansion force acting on the outer shell, thereby improving the service life of the battery cell.

[0008] In some embodiments, the cushion further comprises a support plate, with the plurality of cushioning members disposed on the side of and connected to the support plate. In the above technical solution, the provision of the support plate allows the plurality of cushioning members to be disposed on the support plate, facilitating the installation and fixation of the cushioning members and facilitating the processing and manufacturing of the entire cushion. This also improves the stability of the entire cushion structure, providing effective support for the battery cell throughout its entire cycle.

[0009] In some embodiments, the plurality of buffer members are bonded to the support plate. In the above technical solution, the plurality of buffer members can be directly bonded to the support plate to achieve combined assembly of the buffer pad, which simplifies the assembly process and facilitates assembly and molding, thereby reducing the manufacturing difficulty and manufacturing cost of the entire buffer pad.

[0010] In some embodiments, the distance between two adjacent buffer members is L, and the range of L is 0-5 mm. In the above technical solution, the problem of uneven local stress caused by the large distance between the two buffer members can be avoided, thereby improving the support effect of the buffer pad.

[0011] 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 pad due to excessive thickness, but also improves the support effect on the buffer component and the support capacity of the buffer pad, thereby meeting the requirements for anti-deformation performance during vacuum baking; or during the cycling of the battery cell, the buffer pad can provide strong support and reduce deformation of the pole piece.

[0012] In some embodiments, the compressibility of the support plate at 1 MPa is less than 5%. In the above technical solution, by limiting the compressibility of the support plate to within 5%, the support plate can achieve a reliable support effect on the buffer, thereby improving the support performance of the buffer pad.

[0013] In some embodiments, the support plate is made of at least one of 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, thereby improving the support performance of the buffer pad.

[0014] In some embodiments, a plurality of the buffer members are provided on opposite sides of the support plate, and the plurality of the buffer members are symmetrically arranged on both sides of the support plate. In the above technical solution, by providing a plurality of symmetrically arranged buffer members on both sides of the support plate, the buffer pads are symmetrically arranged along the center plane of the support plate. This prevents the buffer pads from moving and deforming in their length or width directions when the electrode assembly expands, thereby improving the stability of the buffer pads and further enhancing the reliability of the buffer pad support.

[0015] In some embodiments, the dimension of each buffer member in the arrangement direction of the plurality of buffer members is B, and the range of B is 5mm-20mm. In the above technical solution, the problem of uneven local stress can be avoided to a certain extent while facilitating the assembly of the buffer pad, thereby improving the supporting effect of the buffer pad.

[0016] In some embodiments, the buffer member has a dimension H in a direction perpendicular to the arrangement of the plurality of buffer members, and H ranges from 0.5 mm to 10 mm. In the above technical solution, the energy density of the battery cell can be increased, and the buffer pad can be effectively compressed when the electrode assembly expands, thereby reducing the subsequent expansion force of the battery cell.

[0017] In some embodiments, two adjacent buffer members are connected to each other. In the above technical solution, by connecting a plurality of buffer members to each other, the entire buffer pad can be assembled, thereby improving the stability of the buffer pad.

[0018] In some embodiments, two adjacent buffer members are bonded together. In the above technical solution, the entire buffer pad can be assembled by bonding multiple buffer members, which is convenient for assembly and can reduce manufacturing costs.

[0019] In some embodiments, the buffer pad includes a plurality of first buffer members and a plurality of second buffer members, each of the first buffer members and each of the second buffer members extending along a second direction, and the plurality of first buffer members and the plurality of second buffer members are staggered along the first direction, the first direction being perpendicular to the second direction, and under the same pressure, the rebound rate of the first buffer member is less than the rebound rate of the second buffer member. In the above technical solution, by using first and second buffer members with different rebound rates, the buffer pad can have both high rebound resilience and good support, thereby playing a supporting role throughout the entire cycle of battery cell use and meeting the use requirements of the battery cell. At the same time, the buffer pad can be compressed and deformed when the electrode assembly expands to alleviate the expansion force acting on the outer shell, thereby increasing the service life of the battery cell. At the same time, using only two types of buffer members can reduce the manufacturing cost of the buffer pad and facilitate the manufacture and assembly of the buffer pad.

[0020] In some embodiments, the area of ​​the first buffer member is S1, the area of ​​the second buffer member is S2, and the ratio S1 / (S1+S2) is in the range of 30%-70%. This technical solution ensures that the buffer pad effectively supports the electrode assembly throughout the battery cell charge and discharge cycle, reducing the likelihood of problems such as electrode wrinkling and interface abnormalities.

[0021] In some embodiments, after reciprocating application of a first pressure, the first buffer member has a rebound rate of no greater than 50%, and the second buffer member has a rebound rate of no less than 90%. The first pressure ranges from 0.8 MPa to 1.2 MPa. In this technical solution, the buffer pad can effectively support the electrode assembly throughout the battery cell's charge and discharge cycle, reducing the likelihood of problems such as electrode wrinkling and interface abnormalities.

[0022] In some embodiments, the compression rate of the first buffer member under the first pressure is 70%-90%, and the compression rate of the second buffer member under the first pressure is 70%-90%. The first pressure ranges from 0.8 MPa to 1.2 MPa. In the above technical solution, when the electrode assembly expands, the two buffer members can be roughly compressed to the same thickness, thereby uniformly applying force to the electrode assembly, effectively alleviating the expansion force on the outer shell, and improving the reliability of the entire battery cell.

[0023] In some embodiments, the compression rate of the first buffer member under the second pressure is 5%-20%, the compression rate of the first buffer member under the second pressure is not less than 30%, and the second pressure is less than the first pressure. In the above technical solution, during the early stages of battery cell recycling, the first buffer member can effectively support the electrode assembly, reduce electrode deformation, alleviate electrode wrinkling caused by expansion, mitigate lithium or sodium deposition during cycling, and ensure normal battery cell interfaces.

[0024] In some embodiments, the buffer member is a porous material member. In the above technical solution, by adopting such a porous material member, the compressibility of the buffer pad can be improved while reducing the manufacturing cost.

[0025] In some embodiments, the first cushioning member is made of at least one of polyethylene and polypropylene, and the second cushioning member is made of at least one of polyurethane, silicone rubber, and melamine. In the above technical solution, by using these materials, the first cushioning member has a greater resilience than the second cushioning member, while reducing manufacturing costs.

[0026] In a second aspect, the present application provides a battery cell comprising a housing, an electrode assembly, and a buffer pad provided according to the first aspect of the present application, wherein the buffer pad and the electrode assembly are both disposed within the housing. In the above technical solution, the buffer pad can provide support throughout the battery cell's entire cycle, meeting the battery cell's operational requirements. Furthermore, the buffer pad can compress and deform when the electrode assembly expands, thereby alleviating the expansion force acting on the housing and extending the battery cell's service life.

[0027] In some embodiments, the arrangement direction of the plurality of buffer members is perpendicular to the arrangement direction of the buffer pad and the electrode assembly. In the above technical solution, the plurality of buffer members can all contact the electrode assembly, thereby effectively supporting the electrode assembly. When the electrode assembly expands, the buffer pad can be compressed and deformed, effectively alleviating the expansion force acting on the outer shell, and at the same time can reduce the space occupied by the buffer pad in the battery cell, thereby improving the energy density of the battery cell.

[0028] In some embodiments, the buffer pad is provided between the housing and the electrode assembly. In the above technical solution, the buffer pad is provided between the housing and the electrode assembly, which is convenient for 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 pad is disposed between two adjacent electrode assemblies. In the above technical solution, by disposing the buffer pad between the electrode assemblies, the buffer pad 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 pad, the battery cell group margin is maintained between 96% and 105%. That is, in the thickness direction of the battery cell, the buffer pad and the electrode assembly can roughly fill the entire inner cavity of the shell, thereby ensuring to a certain extent that the buffer pad can effectively support the electrode assembly, thereby reducing the problem of interface abnormalities such as electrode wrinkling caused by the failure of the buffer pad to support the electrode assembly.

[0031] In some embodiments, the ratio of the thickness of the buffer pad 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 pad can also 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 electrode sheets arranged in a wound manner, and the outer peripheral surface of the electrode assembly includes a straight portion and a bend connected to the end of the straight portion, and at least one of the straight portion and the bend is disposed opposite the buffer pad; or, the electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked along a third direction, and the buffer pad is disposed opposite the surface of at least one side of the electrode assembly along the third direction. In the above technical solution, the buffer pad corresponds to the plurality of electrode sheets, thereby effectively supporting the electrode assembly and reducing wrinkling of the electrode sheets. At the same time, when the electrode assembly expands, the large surface will expand relatively more. Therefore, by arranging the buffer pad opposite the large surface of the electrode assembly, the expansion of the large surface can be absorbed as much as possible, reducing the stress on the electrode assembly caused by expansion.

[0033] In a third aspect, the present application provides a battery comprising the battery cell in the above embodiment.

[0034] 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.

[0035] 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

[0036] 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:

[0037] FIG1 is a schematic diagram of an electric device in the related art;

[0038] FIG2 is a schematic diagram of a battery in the related art;

[0039] FIG3 is a schematic diagram of a battery cell in the related art;

[0040] FIG4 is a schematic diagram of a cushion according to some embodiments of the present application;

[0041] FIG5 is a side view of the embodiment shown in FIG4;

[0042] FIG6 is a schematic diagram of a cushion according to some other embodiments of the present application;

[0043] FIG7 is a cross-sectional view of the embodiment shown in FIG6;

[0044] FIG8 is a schematic diagram of a cushion according to some other embodiments of the present application;

[0045] FIG9 is a schematic diagram of a cushion according to some further embodiments of the present application;

[0046] FIG10 is an enlarged view of circle A in FIG9 ;

[0047] FIG11 is a schematic diagram of a cushion according to some other embodiments of the present application;

[0048] FIG12 is a schematic diagram of the resilience performance of the first buffer member in some embodiments of the present application;

[0049] FIG13 is a schematic diagram of the resilience performance of the second buffer member in some embodiments of the present application;

[0050] FIG14 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0051] FIG15 is a schematic diagram of a battery cell provided in some other embodiments of the present application;

[0052] FIG16 is a schematic diagram of a battery cell provided in some other embodiments of the present application;

[0053] FIG17 is a schematic diagram of an electrode assembly according to some embodiments of the present application.

[0054] Reference numerals: battery 1000 , electrical device 2000 , battery cell 100 , outer shell 110 , housing 111 , end cap 112 , electrode assembly 120 , positive electrode sheet 1201 , negative electrode sheet 1202 , straight portion 121 , bend portion 122 , buffer pad 200 , support plate 10 , buffer member 20 , first buffer member 21 , second buffer member 22 . DETAILED DESCRIPTION

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The term "plurality" used in this application refers to two or more (including two).

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] For example, as shown in Figures 1 and 2, some electrical devices 2000 are powered by batteries 1000. The battery 1000 includes a case and a battery cell 100. The case includes an upper shell and a lower shell. As shown in Figure 3, the battery cell 100 includes an outer shell 110 and an electrode assembly 120. During the cycle operation of the battery cell 100, the electrode assembly 120 will expand repeatedly, and the expansion force acts on the outer shell 110, causing the outer shell 110 to swell and deform.

[0069] In the related art, some designs are to set a buffer pad 200 in the shell 110, and reduce the expansion force on the shell 110 by compressing the buffer pad 200. However, in order to meet the support for the electrode assembly 120, the buffer pad 200 needs to have a certain degree of support. During the recycling of the battery cell 100, especially in the later stage of the cycle, the electrode assembly 120 expands greatly, and the buffer pad 200 needs to be compressed to a greater extent to reduce the space occupied by the buffer pad 200, that is, the buffer pad 200 needs to have good resilience, that is, the ideal buffer pad 200 needs to have good resilience and support, but the two are often incompatible. Good resilience is often easy to compress and cannot provide sufficient support, and cannot play a role in the early stage of use of the battery cell 100. Good support is often poor elasticity, which can play a role in the early stage of use, but cannot rebound after being crushed in the later stage of use, and cannot play a role.

[0070] To this end, the present application proposes a buffer pad 200, which includes: a plurality of buffer members 20, wherein the plurality of buffer members 20 are arranged along a first direction, and the rebound rates of two adjacent buffer members 20 after the same pressure is applied are different.

[0071] In the buffer pad 200 of the above-mentioned structure, by adopting multiple buffer parts 20 with different rebound rates, the buffer pad 200 can have both high rebound elasticity and good support, so as to play a supporting role in the entire cycle of the battery cell 100 and meet the use requirements of the battery cell 100. At the same time, when the electrode assembly 120 expands, the buffer pad 200 can be compressed and deformed to alleviate the expansion force acting on the shell 110, thereby improving the service life of the battery cell 100.

[0072] The buffer pad 200 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.

[0073] 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.

[0074] Hereinafter, a cushioning pad 200 according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0075] As shown in Figures 4-13 , a buffer pad 200 according to an embodiment of the present application is used within a battery cell 100 , which includes a housing 110 and an electrode assembly 120 . The buffer pad 200 includes a plurality of buffer members 20 arranged along a first direction, with adjacent buffer members 20 exhibiting different spring rates after the same pressure is applied.

[0076] As shown in Figures 4 and 5, the buffer pad 200 includes a plurality of buffer components 20. As shown in Figure 4, the plurality of buffer components 20 are arranged in sequence along the left-right direction, and the rebound rates of two adjacent buffer components 20 are different; the plurality of buffer components 20 can also be arranged in multiple rows and columns. For example, the buffer pad 200 includes a plurality of buffer components 20 arranged in the left-right direction and a plurality of buffer components 20 arranged in the up-down direction. In the left-right direction, the rebound rates of two adjacent buffer components 20 are different, and in the up-down direction, the rebound rates of two adjacent buffer components 20 are different; the buffer components 20 can also form a ring, and the plurality of buffer components 20 are arranged in sequence, that is, the plurality of buffer components 20 are arranged in the inside-outside direction, so that the rebound rates of two adjacent buffer components 20 in the inside-outside direction are different.

[0077] The rebound rate here is the ratio of the thickness of the buffer component 20 to the initial free thickness of the buffer component 20 when a certain pressure is applied to the buffer component 20 and the buffer component 20 rebounds after the pressure is removed. Here, the rebound rates of the two adjacent buffer components 20 after the same pressure is applied are different, that is, the rebound rates of the two adjacent buffer components 20 are different after pressure is applied to the two adjacent buffer components 20 and the force is removed.

[0078] It is understandable that the rebound rates of two adjacent buffers 20 are different, and correspondingly, the support properties of the two adjacent buffers 20 are also different. Among the two, the buffer 20 with a higher rebound rate has a poorer support property, and the buffer 20 with a lower rebound rate has a better support property.

[0079] Furthermore, the plurality of buffer members 20 can be formed into two types, wherein the rebound rate of one buffer member 20 is greater than the rebound rate of the other buffer member 20, and the two buffer members 20 with different rebound rates are arranged alternately, that is, there is a buffer member 20 with another rebound rate between two adjacent buffer members 20 with the same rebound rate; the plurality of buffer members 20 can also be formed into multiple types, for example, the plurality of buffer members 20 are formed into three types, and the three types of buffer members 20 are arranged alternately so that the rebound rates of two adjacent buffer members 20 are different.

[0080] The buffer pad 200 is formed by a plurality of buffer members 20 with different rebound rates, so that the buffer pad 200 has a certain support and a certain resilience. When the buffer pad 200 is placed inside the battery cell 100, at least one of the plurality of buffer members 20 contacts one of the electrode assembly 120 and the shell 110, that is, the positioning and fixation of the buffer pad 200 is achieved, and the side or the other side of the buffer pad 200 contacts the electrode assembly 120. In addition, due to the different rebound rates of the two adjacent buffer members 20, in the early stage of the cycle of the battery cell 100, the buffer member 20 with a lower rebound rate has better support, and the buffer member 20 has a lower rebound rate. It can support the electrode assembly 120; in the later stage of the battery cell 100 cycle, even if the buffer part 20 with a lower rebound rate is difficult to return to the initial thickness and is separated from the electrode assembly 120, the buffer part 20 with a higher rebound rate can always maintain contact with the electrode assembly 120. At this time, the buffer part 20 plays an effective supporting role for the electrode assembly 120. Therefore, the buffer pad 200 can effectively support the electrode assembly 120 during the entire cycle of the battery, reduce the deformation of the pole piece, improve the wrinkling of the pole piece caused by expansion, alleviate the problem of lithium or sodium precipitation during the cycle, and ensure the normal interface of the battery cell 100.

[0081] At the same time, during the recycling of the battery cell 100, the buffer pad 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 pad 200 can have a larger compression amount, reducing the space occupied by the buffer pad 200 itself, and to a certain extent ensuring the expandable space of the electrode assembly 120, thereby reducing the expansion force of the battery cell 100.

[0082] In the buffer pad 200 of the above-mentioned structure, by adopting multiple buffer parts 20 with different rebound rates, the buffer pad 200 can have both high rebound elasticity and good support, so as to play a supporting role in the entire cycle of the battery cell 100 and meet the use requirements of the battery cell 100. At the same time, when the electrode assembly 120 expands, the buffer pad 200 can be compressed and deformed to alleviate the expansion force acting on the shell 110, thereby improving the service life of the battery cell 100.

[0083] As shown in FIG. 8 to FIG. 11 , in some embodiments, the buffer pad 200 further includes: a support plate 10 , and a plurality of buffer members 20 are disposed on a side of the support plate 10 and connected to the support plate 10 .

[0084] As shown in Figures 8 to 11, the support plate 10 is an integral plate-like structure, and the buffer member 20 is arranged on the support plate 10. As shown in Figures 8 to 10, multiple buffer members 20 are arranged on one side of the support plate 10. At this time, the buffer member 20 can contact the outer shell 110 or the electrode assembly 120, and the support plate 10 can also contact the outer shell 110 or the electrode assembly 120; as shown in Figure 11, multiple buffer members 20 are respectively arranged on opposite sides of the support plate 10. At this time, the buffer members 20 on both sides can contact the outer shell 110 or the electrode assembly 120.

[0085] It can be understood that the initial thicknesses of the multiple buffer members 20 can all be the same. Here, the thickness of the buffer member 20 is the size of the buffer member 20 in the direction perpendicular to the plane of the support plate 10. Since the rebound properties of the multiple buffer members 20 are different, during the recycling of the battery cell 100, the thicknesses of the multiple buffer members 20 change differently with the expansion of the electrode assembly 120. Since the buffer member 20 is arranged on the support plate 10, the problem of breakage of the entire buffer pad 200 caused by the change in the thickness of the buffer member 20 can be avoided, the stability of the structure of the buffer pad 200 is improved, and at the same time, to a certain extent, it is ensured that the buffer pad 200 can play an effective supporting role in the entire cycle of the battery cell 100.

[0086] In the above technical solution, by setting the support plate 10, multiple buffer parts 20 can be set on the support plate 10, which is conducive to the installation and fixation of the buffer parts 20 and facilitates the processing and manufacturing of the entire buffer pad 200; at the same time, the stability of the structure of the entire buffer pad 200 can be improved, so as to play an effective supporting role during the entire cycle of the battery cell 100.

[0087] As shown in FIG. 8 , in some embodiments, a plurality of buffer members 20 are bonded to the support plate 10 .

[0088] In the above technical solution, multiple buffer parts 20 can be directly bonded to the support plate 10 to realize the combined assembly of the buffer pad 200. The assembly process is simple and easy to assemble and form, which reduces the manufacturing difficulty of the entire buffer pad 200 and reduces the manufacturing cost.

[0089] As shown in FIG. 10 , in some embodiments, the distance between two adjacent buffer members 20 is L, and the range of L is 0-5 mm.

[0090] As shown in Figures 9 and 10, two adjacent buffer members 20 are arranged at intervals along the left-right direction. By arranging the buffer members 20 at intervals, gaps are formed on the buffer pad 200, thereby reducing the effective area of ​​the buffer pad 200. On the basis of ensuring that the buffer pad 200 has a certain degree of support, the compressibility of the entire buffer pad 200 is improved.

[0091] In addition, the distance between two adjacent buffer members 20 is L. Of course, if two adjacent buffer members 20 are arranged at intervals in the up and down directions, the distance between the two adjacent buffer members 20 is still defined as L. If L is too large, that is, the distance between two adjacent buffer members 20 is too large, it will cause local stress unevenness, and it will easily lead to too few total buffer members 20, and the contact surface between the buffer pad 200 and the electrode assembly 120 or the shell 110 is too small, making it difficult to play an effective supporting effect. For this reason, L is limited to a range of no more than 5 mm, that is, L can be 5 mm, or any value less than 5 mm, for example, L is 1 mm, 2 mm, 3 mm, 4 mm, etc., thereby avoiding the problem of local stress unevenness caused by the distance between the two buffer members 20 being too large, and improving the supporting effect of the buffer pad 200.

[0092] As shown in Figure 8, two adjacent buffer parts 20 are arranged in sequence along the left and right directions, wherein the distance L between the two adjacent buffer parts 20 is 0. Thus, multiple buffer parts 20 are fitted in sequence, which can avoid the problem of local uneven stress to a certain extent and improve the supporting effect of the buffer pad 200.

[0093] As shown in FIG. 10 , in some embodiments, the thickness of the support plate 10 ranges from 30 μm to 200 μm.

[0094] As shown in Figure 10, if the thickness H1 of the support plate 10 is too large, it is easy to cause the buffer pad 200 to be too thick, and the buffer pad 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 pad 200 will increase, and the buffer pad 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 pad 200 to be too low, and the fixing reliability of the buffer part 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, and 200um.

[0095] In this way, it is possible to avoid to a certain extent the problem that the buffer pad 200 is too thick, resulting in the buffer pad 200 occupying too much space and the buffer pad 200 being difficult to compress, and it is also possible to improve the support effect on the buffer part 20 and the support capacity of the buffer pad 200, thereby meeting the requirements for anti-deformation performance during vacuum baking; or during the cycle of the battery cell 100, the buffer pad 200 can provide stronger support capacity and reduce pole piece deformation.

[0096] In some embodiments, the compressibility of the support plate 10 at 1 MPa is less than 5%.

[0097] 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.

[0098] 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 member 20 , thereby improving the support performance of the buffer pad 200 .

[0099] In some embodiments, the material of the support plate 10 includes at least one of polyethylene, polymethacrylate, polyethylene terephthalate, and polytetrafluoroethylene.

[0100] 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 part 20, thereby improving the support performance of the buffer pad 200.

[0101] As shown in FIG. 11 , in some embodiments, a plurality of buffer members 20 are respectively provided on two opposite sides of the support plate 10 , and the plurality of buffer members 20 are symmetrically arranged on both sides of the support plate 10 .

[0102] As shown in Figure 11, buffer members 20 are respectively provided on the front and rear sides of the support plate 10, and the buffer members 20 correspond in position in the front and rear directions. Specifically, the number of buffer members 20 on the front side of the support plate 10 is the same as the number of buffer members 20 on the rear side of the support plate 10, and the buffer members 20 on the front side of the support plate 10 correspond one-to-one to the buffer members 20 on the rear side of the support plate 10. On the front side of the support plate 10, the distance between two adjacent buffer members 20 is L1, and on the rear side of the support plate 10, the distance between two adjacent buffer members 20 is L2, and L1 is the same as L2.

[0103] In some examples, the front side of the support plate 10 has a first buffer 21 and a second buffer 22, and the first buffer 21 and the second buffer 22 are arranged alternately in the left and right directions, and the rear side of the support plate 10 has a first buffer 21 and a second buffer 22, and the first buffer 21 and the second buffer 22 are arranged alternately in the left and right directions, wherein the first buffer 21 on the front side of the support plate 10 is arranged opposite to the first buffer 21 on the rear side of the support plate 10, and the second buffer 22 on the front side of the support plate 10 is arranged opposite to the second buffer 22 on the rear side of the support plate 10, so that the entire buffer pad 200 is arranged symmetrically along the center plane of the support plate 10.

[0104] In the above technical solution, a plurality of symmetrically arranged buffer members 20 are respectively provided on both sides of the support plate 10, so that the buffer pad 200 is symmetrically arranged along the center plane of the support plate 10. Thus, when the electrode assembly 120 expands, the buffer pad 200 can be prevented from moving and deforming in its length or width direction, thereby improving the stability of the buffer pad 200 and further improving the reliability of the support of the buffer pad 200.

[0105] As shown in FIG. 10 , in some embodiments, the dimension of each buffer member 20 in the arrangement direction of the plurality of buffer members 20 is B, and the range of B is 5 mm-20 mm.

[0106] As shown in Figure 10, multiple buffer parts 20 are arranged in the left and right directions. In the left and right directions, if the width of the buffer part 20 is too large, it will cause local uneven stress. If the width of the buffer part 20 is too small, it will be difficult to manufacture the buffer part 20, and the difficulty of assembly will be increased. At the same time, the number of buffer parts 20 required will increase, which will increase the workload of assembling the buffer pad 200. For this reason, B is limited to the range of 5mm-20mm, that is, B can be 5mm, 20mm, or any value between 5mm-20mm, for example, B is 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, etc., thereby facilitating the assembly of the buffer pad 200 and avoiding the problem of local uneven stress to a certain extent, thereby improving the supporting effect of the buffer pad 200.

[0107] As shown in FIG. 10 , in some embodiments, the buffer member 20 has a dimension H in a direction perpendicular to the arrangement of the plurality of buffer members 20 , and the dimension H ranges from 0.5 mm to 10 mm.

[0108] As shown in FIG10 , if the thickness dimension H of the buffer member 20 (the thickness of the buffer member 20 in its free state) is too small in the front-to-back direction, the space for compression and deformation of the buffer pad 200 is limited. When the electrode assembly 120 expands, the buffer pad 200 compresses less, making it difficult to cushion the expansion force exerted on the housing 110. If the thickness dimension H of the buffer member 20 is too large, the buffer member 20 occupies too much space, resulting in a reduction in the energy density within the battery cell 100. Therefore, H is limited to 0.5 mm to 10 mm. H can be 0.5 mm, 10 mm, or any other value between 0.5 mm and 10 mm, such as 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, etc. This improves the energy density of the battery cell 100. At the same time, the buffer pad 200 can be effectively compressed when the electrode assembly 120 expands, thereby reducing the subsequent expansion force of the battery cell 100.

[0109] As shown in FIG. 5 , in some embodiments, two adjacent buffer members 20 are connected to each other.

[0110] The entire buffer pad 200 can be assembled by connecting two adjacent buffer members 20 , wherein the connection methods include bonding, plugging, etc., thereby improving the stability of the buffer pad 200 .

[0111] It is understandable that the buffer pad 200 can be formed into a sheet shape, wherein the buffer pad 200 can be formed into a square sheet shape, a round sheet shape, or a triangular sheet shape. By setting it as a sheet structure, the buffer pad 200 is facilitated to be installed in the battery cell 100, while minimizing the space occupied by the buffer pad 200.

[0112] As shown in FIG. 5 , in some embodiments, two adjacent buffer members 20 are bonded together.

[0113] The entire cushion pad 200 can be assembled by bonding and matching multiple cushioning components 20 in sequence, which facilitates assembly and reduces manufacturing costs.

[0114] As shown in Figures 6 to 13, in some embodiments, the buffer pad 200 includes a plurality of first buffer members 21 and a plurality of second buffer members 22, and the plurality of first buffer members 21 and the plurality of second buffer members 22 are arranged alternately along the first direction, and each first buffer member 21 and each second buffer member 22 extend along the second direction respectively, and the first direction is perpendicular to the second direction. Under the same pressure, the rebound rate of the first buffer member 21 is less than the rebound rate of the second buffer member 22.

[0115] As shown in Figures 6, 12 and 13, the first buffer member 21 and the second buffer member 22 respectively form a strip buffer member 20, and the first buffer member 21 and the second buffer member 22 are arranged alternately in the left and right directions. There is a second buffer member 22 between two adjacent first buffer members 21, and there is a first buffer member 21 between two adjacent second buffer members 22. As a result, the first buffer member 21 and the second buffer member 22 are evenly distributed, the rebound rate of the second buffer member 22 is greater than the rebound rate of the first buffer member 21, and the support of the first buffer member 21 is better than that of the second buffer member 22.

[0116] In the early stage of the cycle of the battery cell 100, the first buffer member 21 has good support, and the first buffer member 21 can effectively support the electrode assembly 120; in the later stage of the cycle of the battery cell 100, even if the first buffer member 21 is difficult to return to its initial thickness and is separated from the electrode assembly 120, the second buffer member 22 can maintain contact with the electrode assembly 120 due to its high rebound rate. At this time, the second buffer member 22 can effectively support the electrode assembly 120. Therefore, the buffer pad 200 can effectively support the electrode assembly 120 throughout the entire cycle of the battery, reduce the deformation of the electrode sheet, improve the wrinkling of the electrode sheet caused by expansion, alleviate the problem of lithium or sodium precipitation during the cycle, and ensure that the interface of the battery cell 100 is normal.

[0117] At the same time, during the recycling of the battery cell 100, the buffer pad 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 pad 200 can have a larger compression amount, reducing the space occupied by the buffer pad 200 itself, and to a certain extent ensuring the expandable space of the electrode assembly 120, thereby reducing the expansion force of the battery cell 100.

[0118] In the buffer pad 200 of the above-mentioned structure, by adopting the first buffer part 21 and the second buffer part 22 with different rebound rates, the buffer pad 200 can have both high rebound elasticity and good support, so as to play a supporting role in the entire cycle of the battery cell 100 and meet the use requirements of the battery cell 100. At the same time, when the electrode assembly 120 expands, the buffer pad 200 can be compressed and deformed to alleviate the expansion force acting on the shell 110, thereby improving the service life of the battery cell 100. At the same time, only two buffer parts 20 are used, which can reduce the manufacturing cost of the buffer pad 200 and facilitate the manufacture and assembly of the buffer pad 200.

[0119] As shown in FIG. 6 , in some embodiments, the area of ​​the first buffer member 21 is S1 , the area of ​​the second buffer member 22 is S2 , and the range of S1 / ( S1 + S2 ) is 30%-70%.

[0120] The area here is the area of ​​the contact surface between the buffer member 20 and the electrode assembly 120 or the shell 110, as shown in Figure 6. Here, the sum of S1 and S2 can be equal to the total area of ​​the entire buffer pad 200. As shown in Figure 6, here, the sum of S1 and S2 can also be less than the total area of ​​the entire buffer pad 200.

[0121] As shown in Figure 6, if the area occupied by the first buffer member 21 is too small, in the early stage of the battery cell 100 cycle charge and discharge, the first buffer member 21 has little supporting effect on the electrode assembly 120, and it is difficult to play an effective supporting effect, resulting in wrinkling of the electrode sheet and abnormal interface of the battery cell 100. If the area occupied by the first buffer member 21 is too large, the area occupied by the second buffer member 22 is too small. In the late stage of the battery cell 100 cycle charge and discharge, the second buffer member 22 has little supporting effect on the electrode assembly 120 and it is difficult to play an effective supporting effect. At this time, it will still cause wrinkling of the electrode sheet and abnormal interface of the battery cell 100. For this reason, the range of S1 / (S1+S2) can be limited to 30%-70%. S1 / (S1+S2) can be 30%, 70%, or any value between 30%-70%, for example, S1 / (S1+S2) is 40%, 50%, 60%, etc.

[0122] This ensures that during the entire charge and discharge cycle of the battery cell 100, the buffer pad 200 can effectively support the electrode assembly 120, reducing the probability of problems such as electrode wrinkling and interface abnormalities.

[0123] As shown in FIG12 and FIG13 , in some embodiments, after the first pressure is reciprocally applied, the rebound rate of the first buffer member 21 is not greater than 50%, the rebound rate of the second buffer member 22 is not less than 90%, and the range of the first pressure is 0.8 MPa-1.2 MPa.

[0124] Here, the first pressure can be roughly the same as the expansion force of the electrode assembly 120. By applying the first pressure back and forth, the force condition of the buffer pad 200 located in the battery cell 100 can be simulated. The rebound rate of the first buffer component 21 is less than the rebound rate of the second buffer component 22. The first buffer component 21 can play a supporting role in the early stage of the battery cell 100 charge and discharge cycle, and the second buffer component 22 can play a supporting role in the later stage of the battery cell 100 charge and discharge cycle. This ensures that during the entire charge and discharge cycle of the battery cell 100, the buffer pad 200 can effectively support the electrode assembly 120, reducing the probability of problems such as electrode wrinkling and interface abnormalities.

[0125] For example, the first pressure can be 0.8MPa, 0.9MPa, 1.0MPa, 1.1MPa, or 1.2MPa; further, the value range of the first pressure can be 0.8MPa-1.0MPa, and the first pressure can be repeatedly applied 30 times, 40 times, 50 times, 60 times, etc.

[0126] It should be noted that, when the pressure applied to the first buffer member 21 or the second buffer member 22 is less than the first pressure, the rebound rate of the first buffer member 21 and the rebound rate of the second buffer member 21 are greater than their rebound rates under the first pressure. For example, when the pressure applied to the first buffer member 21 or the second buffer member 22 is relatively small, the first buffer member 21 and the second buffer member 22 can rebound to their initial state, that is, when the buffer pad 20 is arranged inside the battery cell 100 and before the battery cell 100 is charged and discharged, the pressure applied to the buffer pad 20 is relatively small. Therefore, the first buffer member 21 can restore its initial free thickness after being removed, and the second buffer member 22 can restore its initial free thickness after being removed.

[0127] As shown in FIG12 and FIG13 , the compression rate of the first buffer member 21 under the first pressure is 70%-90%, and the compression rate of the second buffer member 22 under the first pressure is 70%-90%. The first pressure ranges from 0.8 MPa to 1.2 MPa.

[0128] The compressibility of a buffer 20 is the ratio of the reduced thickness of the buffer 20 when compressed to its free thickness. The compressibility of the buffer 20 can be measured using a vernier caliper. Specifically, the free thickness d1 of the buffer 20 is measured at least three times, and the average value is taken. The buffer 20 is placed between two parallel metal plates and a specific pressure is applied and maintained for one minute. The thickness d2 of the buffer 20 is then measured using a vernier caliper, and the average value is taken at least three times. The compressibility of the buffer 20 is calculated as follows: Compressibility of the buffer 20 (%) = (d2 - d1) / d1 × 100%.

[0129] As shown in Figures 12 and 13, the two buffer members 20 have the same maximum compression rate under the first pressure. Therefore, when the electrode assembly 120 expands, the two buffer members 20 can be roughly compressed to a synchronized thickness, thereby making the force on the electrode assembly 120 uniform, thereby effectively alleviating the expansion force on the outer shell 110 and improving the reliability of the entire battery cell 100.

[0130] For example, when the buffer pad 200 per unit area is subjected to a first pressure, the compression rate of the buffer pad 200 is 70%-90%, the value 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; the value range of the first pressure can be 0.8MPa-1.0MPa.

[0131] The first pressure mentioned above may refer to the expansion force of the battery cell and the gas pressure inside the battery casing.

[0132] In the above technical solution, under the first pressure, the compression amount of the two buffer members 20 can be between 70% and 90%, and the buffer member 20 can have a larger compression amount of the buffer pad 200 to reduce the space occupied by the buffer pad 200 itself, thereby ensuring the expandable space of the electrode assembly 120 to a certain extent, and thereby reducing the expansion force acting on the shell 110.

[0133] As shown in Figures 12 and 13, in some embodiments, the compression rate of the first buffer member 21 under the application of the second pressure is 5%-20%, the compression rate of the first buffer member 21 under the application of the second pressure is not less than 30%, and the second pressure is less than the first pressure.

[0134] The second pressure can be between 0.2 MPa and 0.7 MPa, for example, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, or 0.7 MPa. Under a relatively low pressure, the compression rate of the first buffer member 21 is relatively low, while the compression rate of the second buffer member 22 is relatively high, and the first buffer member 21 has better support than the second buffer member 22.

[0135] Therefore, in the early stage of the battery cell 100 cycle, the first buffer member 21 can effectively support the electrode assembly 120, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, alleviate the lithium or sodium deposition problem during the cycle, and ensure the normal interface of the battery cell 100.

[0136] In some embodiments, the buffer member 20 is a porous material.

[0137] The porous material can be made through a foaming process. By using such a porous material, the compressibility of the buffer pad 200 can be improved while reducing the manufacturing cost.

[0138] In some embodiments, the material of the first buffer component 21 includes at least one of polyethylene and polypropylene, and the material of the second buffer component 22 includes at least one of polyurethane, silicone rubber, and melamine.

[0139] The first buffer component 21 can be made of polyethylene or polypropylene, or a composite material. The second buffer component 22 can be made of polyurethane, silicone rubber, melamine, or a composite material. By adopting the above materials, the manufacturing cost can be reduced while achieving the resilience of the first buffer component 21 being greater than the resilience of the second buffer component 22.

[0140] As shown in FIG. 14 to FIG. 16 , in a second aspect, the present application proposes a battery cell 100 , comprising a housing 110 , an electrode assembly 120 and a buffer pad 200 , wherein the buffer pad 200 and the electrode assembly 120 are both disposed within the housing 110 .

[0141] 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.

[0142] 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.

[0143] The buffer pad 200 is the buffer pad 200 proposed in the first aspect of this application. The buffer pad 200 is arranged in the shell 110, that is, the buffer pad 200 is located inside a battery cell 100. The buffer pad 200 can be located between the shell 110 and the electrode assembly 120, or between adjacent electrode assemblies 120.

[0144] The buffer pad 200 includes multiple buffer parts 20, and the rebound rates of two adjacent buffer parts 20 are different. The rebound rate of one buffer part 20 is lower than that of the other buffer part 20. Therefore, the support of the buffer part 20 is better than that of the other buffer part 20. Therefore, in the early stage of the cycle of the battery cell 1000, the support of the buffer part 20 with a lower rebound rate is better, and the buffer part 20 can support the electrode assembly; in the later stage of the cycle of the battery cell 1000, even if the buffer part 20 with a lower rebound rate is difficult to return to the initial thickness and is separated from the electrode assembly, the buffer part 20 with a higher rebound rate can always maintain contact with the electrode assembly 120. At this time, the buffer part 20 can effectively support the electrode assembly 120. Therefore, the buffer pad 200 can effectively support the electrode assembly 120 throughout the entire cycle of the battery, reduce the deformation of the electrode, improve the wrinkling of the electrode caused by expansion, alleviate the problem of lithium or sodium precipitation during the cycle, and ensure the normal interface of the battery cell 1000.

[0145] At the same time, during the recycling of the battery cell 1000, the buffer pad 200 can be compressed and deformed to alleviate the expansion force of the electrode assembly on the outer shell. At the same time, in the later stage of the cycle, the buffer pad 200 can have a larger compression amount, reducing the space occupied by the buffer pad 200 itself, and to a certain extent ensuring the expandable space of the electrode assembly, thereby reducing the expansion force of the battery cell 1000.

[0146] In the battery cell 1000 of the above-mentioned structure, the buffer pad 200 can play a supporting role throughout the entire cycle of the battery cell 1000 to meet the usage requirements of the battery cell 1000. At the same time, when the electrode assembly expands, the buffer pad 200 can be compressed and deformed to alleviate the expansion force acting on the outer shell, thereby improving the service life of the battery cell 1000.

[0147] In some embodiments, the arrangement direction of the plurality of buffer members 20 is perpendicular to the arrangement direction of the buffer pad 200 and the electrode assembly 120 .

[0148] As shown in Figures 14 to 16, the buffer pad 200 is located on the front or rear side of the electrode assembly 120, that is, the buffer pad 200 and the electrode assembly 120 are arranged in the front-to-back direction, and the arrangement direction of the multiple buffer parts 20 can be arranged in the up-down direction or in the left-right direction, so that the multiple buffer parts 20 can all contact with the electrode assembly 120, and thus can effectively support the electrode assembly 120. When the electrode assembly expands, the buffer pad 200 can be compressed and deformed, effectively alleviating the expansion force acting on the outer shell, and at the same time can reduce the space occupied by the buffer pad 200 in the battery cell 100, thereby improving the energy density of the battery cell 1000.

[0149] As shown in FIG. 14 , in some embodiments, a buffer pad 200 is provided between the housing 110 and the electrode assembly 120 .

[0150] By arranging the buffer pad 200 between 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 pole piece; in addition, when the battery cell 100 is charged and discharged, as the electrode assembly 120 expands, the buffer pad 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 cycle and extending the service life of the battery cell 100.

[0151] In the above technical solution, the buffer pad 200 is arranged between the shell 110 and the electrode assembly 120, which is easy to install and can reduce the stress on the shell 110 when the electrode assembly 120 expands, effectively reducing the probability of deformation of the shell 110.

[0152] 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 pad 200 is disposed between two adjacent electrode assemblies 120 .

[0153] As shown in Figures 15 and 16, a buffer pad 200 is provided between adjacent electrode assemblies 120. For example, a buffer pad 200 can be provided between any two adjacent electrode assemblies 120, or between two partially adjacent electrode assemblies 120. Thus, the number of buffer pads 200 can be one or more.

[0154] In the above technical solution, by arranging the buffer pads 200 between the electrode assemblies 120 , the buffer pads 200 can effectively absorb the expansion of the electrode assemblies 120 and reduce the stress on the housing 110 when the electrode assemblies 120 expand.

[0155] As shown in FIG16 , a plurality of buffer pads 200 are provided in the battery cell 100, at least one buffer pad 200 is arranged between the outer shell 110 and the electrode assembly 120, and at least one buffer pad 200 is arranged between two adjacent electrode assemblies 120. Thus, by arranging a plurality of buffer pads 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.

[0156] In some embodiments, the group margin of the battery cells 100 ranges from 96% to 105%.

[0157] 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 pad 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 pad 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 pad 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 pad 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 pad 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 pad 200 to support the electrode assembly 120.

[0158] Preferably, the group margin range of the battery cell 100 is 98%-103%, which can further improve the support of the buffer pad 200 for the electrode assembly 120, especially reduce the interface abnormality problems such as electrode wrinkling caused by the failure of the buffer pad 200 to support the electrode assembly 120 in the fully charged state.

[0159] In some embodiments, the ratio of the thickness of the buffer pad 200 to the thickness of the electrode assembly 120 is in a range of 2% to 15%.

[0160] Here, the thickness of the buffer pad 200 is the thickness of the buffer pad 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 pad 200 is too much, it is easy to affect the energy density of the battery cell 100. If the thickness of the buffer pad 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 pad 200 is limited, resulting in excessive expansion force. For this reason, the buffer pad 200 is compressed to a certain extent. The ratio of the thickness of the buffer pad 200 to the thickness of the electrode assembly 120 is limited to between 2% and 15%, and the ratio of the thickness of the buffer pad 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 pad 200 to play an effective buffering role, reduce the expansion force on the shell 110 when the electrode assembly 120 expands, and effectively reduce the probability of deformation of the shell 110.

[0161] Preferably, the ratio of the thickness of the buffer pad 200 to the thickness of the electrode assembly 120 is 5%-10%, that is, the ratio of the thickness of the buffer pad 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 pad 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.

[0162] In the embodiment of the present application, the location of the buffer pad 200 relative to the electrode assembly 120 can be flexibly set according to the structure of the electrode assembly 120 .

[0163] 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 pad.

[0164] 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.

[0165] The straight portion 121 is arranged opposite to the buffer pad 200, so that the buffer pad 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 pad 200, so that the area of ​​the buffer pad 200 facing the bend portion 122 is roughly formed into an arc shape, so that the buffer pad 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.

[0166] Furthermore, when the buffer pad 200 is located on one side of the straight portion 121 (the front side or the rear side as shown in FIG3 ), the arrangement direction of the multiple buffer members 20 is perpendicular to the arrangement direction of the buffer pad 200 and the electrode assembly 120 (the front-to-back direction as shown in FIG3 ); when the buffer pad 200 is located on one side of the bend 122 (the left side or the right side as shown in FIG3 ), the arrangement direction of the multiple buffer members 20 is perpendicular to the arrangement direction of the buffer pad 200 and the electrode assembly 120 (the left-to-right direction as shown in FIG3 ). As a result, the multiple buffer members 20 can all contact the electrode assembly 120, thereby effectively supporting the electrode assembly 120. When the electrode assembly expands, the buffer pad 200 can be compressed and deformed, effectively alleviating the expansion force acting on the shell, and at the same time, the space occupied by the buffer pad 200 in the battery cell 100 can be reduced, thereby improving the energy density of the battery cell 1000.

[0167] 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 third direction, and the buffer pad 200 is arranged opposite to the surface of at least one side of the electrode assembly 120 along the third direction.

[0168] The third 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 third direction. The electrode assembly 120 of the above structure will expand in the third direction during use. Therefore, the buffer pad 200 is arranged relative to the surface of at least one side of the electrode assembly 20 along the third direction, so that the buffer pad 200 can more fully provide buffering and support to the pole sheet, reduce wrinkling of the pole sheet, etc., so that the buffer pad 200 plays an effective buffering and supporting role, and the area required for the buffer pad 200 is small and the cost is low.

[0169] Furthermore, the arrangement direction of the multiple buffer members 20 is perpendicular to the stacking direction of the electrode assembly 120, that is, the first direction is perpendicular to the third direction, so that the multiple buffer members 20 can all contact the electrode assembly 120, and thus can effectively support the electrode assembly 120. When the electrode assembly 120 expands, the buffer pad 200 can be compressed and deformed, effectively alleviating the expansion force acting on the shell 110, and at the same time can reduce the space occupied by the buffer pad 200 in the battery cell 100, thereby improving the energy density of the battery cell 1000.

[0170] In some embodiments, the buffer pad 200 corresponds to at least the largest surface of the electrode assembly 120. As shown in Figures 3 and 14-16, some electrode assemblies 120 have two end surfaces and four side surfaces, of which two oppositely arranged side surfaces have relatively large areas, namely the large surfaces of the electrode assembly 120, and the other two oppositely arranged side surfaces have relatively small areas, namely the small surfaces of the electrode assembly 120. The buffer pad 200 corresponds to the large surfaces, or both the large and small surfaces have corresponding buffer pads 200, or one end surface and the large surface have corresponding buffer pads 200, or both end surfaces and the large surface have corresponding buffer pads 200. The buffer pad 200 corresponds to the large surfaces, thereby effectively supporting the electrode assembly 120 and reducing electrode wrinkling. At the same time, when the electrode assembly 120 expands, the large surface will expand relatively more. Therefore, by placing the buffer pad 200 opposite the large surface of the electrode assembly 120, the expansion of the large surface can be absorbed as much as possible, reducing the stress on the electrode assembly 120 caused by expansion.

[0171] In addition, the buffer pad 200 may be disposed continuously, and disposed between any adjacent electrode assemblies 120 by folding or winding.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] As shown in Figure 1, the battery 1000 is arranged at the bottom of the vehicle, and as shown in Figures 9, 10 and 14, the battery 1000 includes a plurality of battery cells 100, each battery cell 100 includes a shell 110, an electrode assembly 120 and a buffer pad 200, the shell 110 includes a shell 111 and an end cover 112, and the electrode assembly 120 and the buffer pad 200 are arranged in the shell 110.

[0177] The buffer pad 200 includes a support plate 10, a first buffer component 21 and a second buffer component 22. The first buffer component 21 and the second buffer component 22 are bonded to one side surface of the support plate 10, and the first buffer component 21 and the second buffer component 22 are staggered in the left-right direction. Adjacent first buffer components 21 and second buffer components 22 are arranged at intervals, and the distance L between adjacent first buffer components 21 and second buffer components 22 is 1.5 mm; in the left-right direction, the width of the first buffer component 21 is B1, and the width of the second buffer component 22 is B2. In the front-to-back direction, the thickness of the first buffer component 21 is H11, and the thickness of the second buffer component 22 is H12. The thickness here is the initial free thickness, and H11 and H12 are the same; the total area of ​​the first buffer component 21 is S1, and the total area of ​​the second buffer component 22 is S2, and S1 is the same as S2.

[0178] Among them, the first buffer component 21 has high support, its compression amount is 5-20% under 0.2Mpa, and its compression amount is 70-90% under 1MPa pressure. After 50 times of reciprocating compression at 1MP, the rebound rate is less than 50%; the second buffer component 22 has high resilience, its compression amount is >30% under 0.2Mpa, and its compression amount is 70-90% under 1MPa. After 50 times of reciprocating compression at 1MP, the rebound rate is greater than 90%.

[0179] 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 pad used inside a battery cell, wherein: include: A plurality of buffer components are arranged along a first direction, and two adjacent buffer components have different springback rates after the same pressure is applied thereto.

2. The cushioning pad according to claim 1, wherein: The buffer pad further includes a support plate, and the plurality of buffer members are arranged on the side of the support plate and connected to the support plate.

3. The cushioning pad according to claim 2, wherein: The plurality of buffer members are bonded to the support plate.

4. The cushioning pad according to claim 2, wherein: The distance between two adjacent buffer members is L, and the range of L is 0-5 mm.

5. The cushioning pad according to claim 2, wherein: The thickness of the support plate ranges from 30um to 200um.

6. The cushioning pad according to claim 2, wherein: The compressibility of the support plate at 1 MPa is less than 5%.

7. The cushioning pad according to claim 6, wherein: The material of the support plate includes at least one of polyethylene, polymethacrylate, polyethylene terephthalate, and polytetrafluoroethylene.

8. The cushioning pad according to claim 2, wherein: A plurality of the buffer members are respectively disposed on opposite sides of the support plate, and the plurality of the buffer members are symmetrically arranged on the two sides of the support plate.

9. The cushion according to any one of claims 1 to 8, wherein: The dimension of each buffer member in the arrangement direction of the plurality of buffer members is B, and the range of B is 5 mm-20 mm.

10. The cushion according to any one of claims 1 to 9, wherein: The dimension of the buffer member in a direction perpendicular to the arrangement of the plurality of buffer members is H, and the range of H is 0.5 mm-10 mm.

11. The cushion according to any one of claims 1 to 10, wherein: Two adjacent buffer members are connected to each other.

12. The cushioning pad according to claim 11, wherein: Two adjacent buffer components are bonded together.

13. The cushioning pad according to any one of claims 1 to 12, wherein: The buffer pad includes a plurality of first buffer members and a plurality of second buffer members, wherein the plurality of first buffer members and the plurality of second buffer members are arranged alternately along a first direction, and each of the first buffer members and each of the second buffer members extend along a second direction respectively, and the first direction is perpendicular to the second direction. Under the same pressure, the rebound rate of the first buffer member is less than the rebound rate of the second buffer member.

14. The cushioning pad according to claim 13, wherein: The area of ​​the first buffer is S1, the area of ​​the second buffer is S2, and the range of S1 / (S1+S2) is 30%-70%.

15. The cushioning pad according to claim 13, wherein: After the first pressure is reciprocally applied, the rebound rate of the first buffer is not greater than 50%, the rebound rate of the second buffer is not less than 90%, and the range of the first pressure is 0.8 MPa-1.2 MPa.

16. The cushioning pad according to claim 13, wherein: The compression rate of the first buffer member under the application of the first pressure is 70%-90%, the compression rate of the second buffer member under the application of the first pressure is 70%-90%, and the range of the first pressure is 0.8MPa-1.2MPa.

17. The cushioning pad according to claim 15, wherein: The compression rate of the first buffer member under the second pressure is 5%-20%, the compression rate of the first buffer member under the second pressure is not less than 30%, and the second pressure is less than the first pressure.

18. The cushioning pad according to claim 13, wherein: The buffer member is made of porous material.

19. The cushioning pad according to claim 18, wherein: The material of the first buffer member includes at least one of polyethylene and polypropylene, and the material of the second buffer member includes at least one of polyurethane, silicone rubber, and melamine.

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

21. The battery cell according to claim 20, wherein: An arrangement direction of the plurality of buffer members is perpendicular to an arrangement direction of the buffer pad and the electrode assembly.

22. The battery cell according to claim 20 or 21, wherein: The buffer pad is arranged between the shell and the electrode assembly.

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

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

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

26. The battery cell according to any one of claims 20 to 25, 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 pad; or The electrode assembly includes a plurality of positive electrode sheets and a plurality of negative electrode sheets stacked along a third direction, and the buffer pad is disposed opposite to a surface of at least one side of the electrode assembly along the third direction.

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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