Battery cell, battery device and electric device

Abstract

The utility model discloses a battery monomer, a battery device and a power utilization device, and relates to the technical field of batteries. Each single battery comprises a shell, a battery cell assembly, an insulating part and a buffer part, and the shell is provided with an electrode terminal; the battery cell assembly is arranged in the shell, the battery cell assembly comprises a main body section, a first section and a tab section which are connected in sequence, the tab section is further connected with the electrode terminal, and the thickness of the first section is smaller than that of the main body section; the insulating part is arranged in a manner of coating the battery core assembly; the buffer part is arranged on the insulating part and located between the periphery of the first section and the inner wall of the shell. According to the technical scheme, the problem of failure of the battery cell assembly can be reduced while the energy density of the battery monomer is improved.

Description

Technical Field

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

[0002] With the widespread adoption of mobile devices, electric vehicles, and wearable devices, higher demands are being placed on battery energy density. The energy density of a single battery cell directly affects the device's battery life and performance. Currently, battery cell design is gradually moving towards higher energy storage and smaller size.

[0003] In the relevant existing technologies, due to the presence of a tab pressure-affected area and a thinning area at the end of the battery cell assembly, stress concentration is prone to occur in the tab pressure-affected area and the thinning area, leading to wrinkling or lithium plating problems in the battery cell assembly, which in turn leads to battery cell assembly failure. Utility Model Content

[0004] In view of the above problems, this application provides a battery cell, a battery device, and an electrical device, which aims to improve the energy density of the battery cell while reducing the failure of the battery cell assembly.

[0005] In a first aspect, this application provides a battery cell, comprising:

[0006] The outer casing has electrode terminals;

[0007] A battery cell assembly is disposed within the housing. The battery cell assembly includes a main body segment, a first segment, and a tab segment connected in sequence. The tab segment is also connected to the electrode terminal. The thickness of the first segment is less than the thickness of the main body segment.

[0008] Insulating element, covering the battery cell assembly; and

[0009] A buffer element is disposed on the insulating element and located between the outer periphery of the first segment and the inner wall of the outer shell.

[0010] This embodiment provides a buffer element on the insulating component, positioned between the outer periphery of the first segment and the inner wall of the outer casing. When the battery cell assembly expands, the buffer element provides support to the first segment while slowly releasing space, thus offering buffer protection for the first segment and reducing the risk of failure. Furthermore, compared to placing buffer elements across the entire surface area of ​​the battery cell, this method, by only placing buffer elements in the thinned area and the area affected by the tab pressure, occupies less internal space within the battery cell. This allows for more space to be allocated to the battery cell assembly, accommodating active materials and improving the energy efficiency of the battery cell.

[0011] In some embodiments, the buffer element is integrally connected to the insulating element by adhesive bonding or heat fusion. In this embodiment, the buffer element is integrally connected to the insulating element by adhesive bonding and heat fusion, which reduces the number of connecting components between the buffer element and the insulating element. Furthermore, the integral connection of the buffer element to the insulating element by heat fusion improves the reliability of the connection between the buffer element and the insulating element.

[0012] In some embodiments, the buffer is disposed on the side of the insulator near the cell assembly; or the buffer is disposed on the side of the insulator near the housing; or along the direction from the housing toward the cell assembly, the insulator includes multiple insulating layers, and the buffer is disposed between the multiple insulating layers. In this embodiment, the buffer is disposed between the cell assembly and the insulator, which facilitates the installation of the assembled components of the insulator, buffer, and cell assembly into the housing, and allows for better wetting of the active layer material at the first segment; the buffer being disposed on the side of the insulator near the housing facilitates the combination of the buffer and the insulator, and the buffer being disposed inside the insulator reduces the material cost of the buffer.

[0013] In some embodiments, the battery cell assembly includes a positive electrode and a negative electrode. The positive electrode has a first thinning region corresponding to the first segment, and the negative electrode has a second thinning region corresponding to the first segment. The inner wall surface of the housing where the electrode terminals are located is defined as a first end face. The distance between the first thinning region and the first end face is greater than the distance between the second thinning region and the first end face. The positive electrode includes a first current collector, which includes a first current collector portion corresponding to the main body segment, a second current collector portion corresponding to the first thinning region, a first connecting portion configured as the electrode tab, and a second connecting portion connecting the second current collector portion and the first connecting portion. The first current collector portion and the second current collector portion are covered with a first active material layer. The thickness of the first active material layer on the second current collector portion decreases from the first current collector portion toward the second connecting portion. At least a portion of the second connecting portion corresponds to the first segment. In this embodiment, the occurrence of dendrite precipitation at the edge of the negative electrode due to the thinning region at the first segment position of the battery cell assembly can be reduced to a certain extent.

[0014] In some embodiments, the battery cell assembly has two opposing first sides and two opposing second sides, the area of ​​the first side being larger than the area of ​​the second side; the region of the insulating member corresponding to the first side is defined as a first surface region, the region of the insulating member corresponding to the second side is defined as a second surface region, and the buffer member is located only in the first surface region corresponding to the position of the first segment.

[0015] In some embodiments, the housing includes a bottom shell with an opening at one end and an end cap covering the opening; the electrode terminals are disposed on the end cap, the bottom shell and the end cap enclose a mounting cavity, and the battery cell assembly is disposed in the mounting cavity; the housing also includes a top cap disposed in the mounting cavity, the top cap being located on the side surface of the end cap facing the battery cell assembly; the first surface area has a main surface segment corresponding to the main body segment, a first surface segment corresponding to the first segment, and a second surface segment corresponding to the electrode tab segment, the buffer member is disposed on the first surface segment, and the second surface segment is connected to the periphery of the top cap by heat fusion. In this embodiment, the second surface segment facilitates the heat fusion connection between the insulating member and the top cap.

[0016] In some embodiments, a first gap exists between the buffer and the top cover. This embodiment can reduce the impact on the performance of the buffer when the second side section and the top cover are heat-sealed together.

[0017] In some embodiments, a second gap exists between the buffer and the second surface area. This embodiment facilitates the encapsulation of the battery cell assembly after the insulating and buffer components are combined.

[0018] In some embodiments, the compression ratio of the buffer is not less than 50% and not more than 90%. In this embodiment, the buffer can deform over a wide range to absorb more energy, thereby reducing failure caused by over-compression.

[0019] In some embodiments, the elastic modulus of the buffer is not less than 1.5 MPa and not greater than 70 MPa. In this embodiment, the buffer has both a certain degree of flexibility and support, so that it can both cushion impacts and maintain structural stability.

[0020] In some embodiments, the buffer is made of foam, and the porosity of the buffer is not less than 30% and not more than 45%. In this embodiment, the active material layer at the first segment has good wetting properties, reducing the risk of lithium plating due to poor wetting.

[0021] In some embodiments, the buffer has multiple buffer layers, at least two of which have different compressibility ratios; and / or, the buffer has multiple buffer layers, at least two of which have different elastic moduli. In this embodiment, the multi-layered buffer provides wider adaptability and a more efficient cushioning effect by rationally arranging different physical properties in each layer of material.

[0022] In some embodiments, at least one of the buffer layers is made of rubber, and / or at least one of the buffer layers is made of foam. In this embodiment, rubber and foam materials are used in combination. Rubber is suitable for withstanding strong impacts and high pressures, while foam performs well under lightweight and low-intensity impacts. The combination of the two can provide a multi-layered buffering effect, optimizing impact absorption, vibration isolation, and energy dispersion.

[0023] In some embodiments, the buffer is disposed on the side of the insulator close to the cell assembly, and a plurality of buffer layers are stacked and arranged from the insulator toward the cell assembly; the material of the buffer layer connected to the insulator is rubber; and / or, the material of the buffer layer furthest from the insulator is foam. This embodiment can reduce the manufacturing difficulty of the buffer while reducing its weight, which is beneficial for the lightweighting of the battery device.

[0024] In some embodiments, the battery cell assembly has two opposing first sides and two opposing second sides, wherein the area of ​​the first sides is larger than the area of ​​the second sides; the region of the insulating member corresponding to the first side is defined as a first surface region, and the region of the insulating member corresponding to the second side is defined as a second surface region; the buffer member is disposed only in the first surface region corresponding to the position of the first segment, and there is a gap between the buffer member and the second surface region. In this embodiment, it is convenient for the sheet-like insulating member to be folded into a box shape to cover the battery cell assembly.

[0025] In some embodiments, the buffer members are respectively provided at positions corresponding to the first segment on the two first surface areas; wherein at least one of the buffer members has multiple buffer portions, which are spaced apart along the direction from one second surface area to another. In this embodiment, by setting the buffer member in the form of multiple buffer portions, and combining test data, buffer portions with larger compressibility and elastic modulus are used in the parts with relatively severe expansion, while buffer portions with smaller compressibility and elastic modulus are used in the parts with relatively mild expansion, so that the buffer member can cope with this uneven force.

[0026] In some embodiments, the cell assembly has a bottom surface, and the area of ​​the insulating member corresponding to the bottom surface is defined as the bottom surface area; the orthographic projections of two adjacent buffer portions on the bottom surface area overlap; this enables the reduction of the material used in the buffer member while the first segment of the cell assembly has continuous buffer protection along a first direction.

[0027] Secondly, this application provides a battery device, which includes the battery cell described in any of the foregoing embodiments.

[0028] Thirdly, this application provides an electrical device, which includes the battery device described in any of the foregoing embodiments.

[0029] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0031] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0032] Figure 2 This is an exploded view of the battery device according to some embodiments of this application;

[0033] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0034] Figure 4 This is a cross-sectional view of a portion of a battery device according to some embodiments of this application;

[0035] Figure 5 for Figure 4 A magnified view of a specific location;

[0036] Figure 6 This is a schematic diagram of the connection structure of the insulating member and the buffer member in some embodiments of this application;

[0037] Figure 7 This is a schematic diagram of the connection structure of the insulating member and the buffer member in some other embodiments of this application;

[0038] Figure 8 for Figure 7 A side view;

[0039] Figure 9 for Figure 8 A magnified view of a section at point A in the middle;

[0040] Figure 10 This is a schematic diagram of the connection structure of the insulating member and the buffer member in some embodiments of this application;

[0041] Figure 11 This is a cross-sectional view of a portion of a battery device according to some embodiments of this application;

[0042] Figure 12 for Figure 1The diagram shows the structure of the battery cell assembly.

[0043] The reference numerals in the detailed embodiments are as follows:

[0044] 1. Vehicle; 10. Battery unit; 20. Controller; 30. Motor; 11. Battery module; 12. Battery cell; 13. Housing; 13a. First part; 13b. Second part;

[0045] 100. Outer shell; 110. Bottom shell; 120. End cap; 121. Electrode terminal; 130. Top cover; 131. Top plate; 132. Flanged edge; 200. Cell assembly; 201. Main body section; 202. First section; 203. Electrode tab section; 204. First side surface; 205. Second side surface; 210. Positive electrode plate; 211. Positive current collector; 211a. First current collector; 211b. Second current collector; 211c. First connecting part; 211d. Second connecting part; 212. Positive electrode tab 213. Positive electrode active material layer; 220. Negative electrode sheet; 221. Negative electrode current collector; 222. Negative electrode tab; 213. Negative electrode active material layer; 230. Separator; 300. Insulating component; 310. First surface area; 311. Main surface section; 312. First surface section; 313. Second surface section; 320. Second surface area; 330. Bottom surface area; 400. Buffer component; 410. Buffer layer; 411. First buffer layer; 412. Second buffer layer; 413. Third buffer layer; 420. Buffer section;

[0046] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0047] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0049] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0050] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0052] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0053] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0054] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0055] Currently, judging from market trends, the application of power battery devices is becoming increasingly widespread. Power battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace, among other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0056] A battery device typically contains one or more battery cells. A battery cell includes a cell assembly and an electrolyte. The cell assembly is the core component that enables its charging and discharging functions. The cell assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell mainly relies on the movement of metal ions between the positive and negative electrodes to function.

[0057] The electrodes (positive or negative electrodes) of a battery cell assembly typically include a current collector and an active material layer coated on the current collector. During the charge and discharge cycle of a single battery cell, the electrodes expand and contract. During the expansion of the battery cell assembly, the electrodes are deformed by the expansion force.

[0058] The applicant discovered that at the end of the battery cell assembly where the tabs are located, there are a tab-pressure-affected zone and a thinning zone. The thinning zone refers to the area where the edge of the electrode is thinned after processing (meaning the thickness of the active material layer is reduced). Due to the reduced electrode thickness in the thinning zone, the mechanical strength is reduced, and stress concentration is easily generated during charge-discharge cycles due to electrode expansion or external pressure, which can lead to electrode wrinkling or even breakage. Since the tabs are bent from a straight state to a target shape (such as an L-shape or U-shape) through a pressing process to meet the requirements of subsequent packaging or current collector connection, the insufficient ductility of the metal foil during the pressing process may cause stress concentration in the connection area between the tab and the current collector coated with the active material layer, as well as the periphery of this area (the tab-pressure-affected zone), leading to wrinkling or lithium plating problems in the battery cell assembly, and ultimately causing battery cell assembly failure.

[0059] Furthermore, with the increasing prevalence of mobile devices, electric vehicles, and wearable devices, higher demands are being placed on battery energy density, which directly affects the device's battery life and performance. Currently, battery cell design is gradually moving towards higher energy storage and smaller size.

[0060] Based on this, this application provides buffers in the corresponding thinning area and the tab pressure-affected area to provide buffer protection for the tab end of the cell assembly, thereby reducing wrinkling of the cell assembly in the opening thinning area and the tab pressure-affected area. In addition, compared to providing buffers in the entire surface area of ​​the battery cell, since the buffers are only provided in the thinning area and the tab pressure-affected area, the buffers occupy less internal space in the battery cell, which can leave more space for the cell assembly. This space is used to accommodate the cell assembly, which can improve the energy of the battery cell and, as expansion space, can improve the thickness margin of the battery cell.

[0061] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0062] For ease of explanation, the following embodiments will be described using a vehicle 1 as an example of an electrical device according to an embodiment of this application.

[0063] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1 according to some embodiments of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery device 10 is installed inside the vehicle 1, and the battery device 10 can be located at the bottom, front, or rear of the vehicle 1. The battery device 10 can be used to power the vehicle 1; for example, the battery device 10 can serve as the operating power source for the vehicle 1. The vehicle 1 may also include a controller 20 and a motor 30. The controller 20 is used to control the battery device 10 to supply power to the motor 30, for example, to meet the power needs of the vehicle 1 during starting, navigation, and driving.

[0064] In some embodiments of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0065] Please refer to Figure 2 , Figure 2This is an exploded structural diagram of a battery device 10 according to some embodiments of this application. The battery device 10 includes a housing 13 and a battery cell 12, with the battery cell 12 housed within the housing 13. The housing 13 provides a space for the battery cell 12 and can have various structures. In some embodiments, the housing 13 may include a first portion 13a and a second portion 13b, which overlap each other, jointly defining a space for accommodating the battery cell 12. The second portion 13b may be a hollow structure with one open end, and the first portion 13a may be a plate-like structure, covering the open side of the second portion 13b so that the first portion 13a and the second portion 13b jointly define the space. Alternatively, the first portion 13a and the second portion 13b may both be hollow structures with one open side, with the open side of the first portion 13a covering the open side of the second portion 13b. Of course, the box 13 enclosed by the first part 13a and the second part 13b can be of various shapes, such as a cylinder, a cuboid, etc.

[0066] In the battery device 10, there can be multiple battery cells 12. These multiple battery cells 12 can be connected in series, in parallel, or in a mixed manner. A mixed connection means that multiple battery cells 12 are connected in both series and parallel. Multiple battery cells 12 can be directly connected in series, in parallel, or in a mixed manner, and then the whole assembly of multiple battery cells 12 is housed in the housing 13.

[0067] Of course, please refer to Figure 2 , Figure 2 This is an exploded structural diagram of the battery device 10 according to some embodiments of this application. The battery device 10 may also be in the form of multiple battery cells 12 first connected in series, parallel or mixed to form a battery module 11, and then the multiple battery modules 11 are connected in series, parallel or mixed to obtain a whole, which is housed in a housing 13. Alternatively, the battery device 10 may have only one battery module 11, which is housed in the housing 13. The battery device 10 may also include other structures, for example, the battery device 10 may also include a busbar for realizing the electrical connection between multiple battery cells 12.

[0068] Each battery cell 12 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 12 can be cylindrical, flat, cuboid, or other shapes.

[0069] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell 12 according to some embodiments of this application; the battery cell 12 refers to the smallest unit that makes up a battery. Figure 3The battery cell 12 includes a housing 100, a cell assembly 200, and other functional components. The housing 100 includes an end cap 120 and a bottom shell 110.

[0070] End cap 120 refers to a component that covers the opening of bottom shell 110 to isolate the internal environment of battery cell 12 from the external environment. The shape of end cap 120 can be adapted to the shape of bottom shell 110 to fit it. Optionally, end cap 120 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 120 is not easily deformed under pressure and impact, allowing battery cell 12 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 121 can be provided on end cap 120. Electrode terminals 121 can be used for electrical connection with cell assembly 200 to output or input electrical energy from battery cell 12. In some embodiments, end cap 120 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 12 reaches a threshold. The material of end cap 120 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating member 300 may be provided on the inner side of the end cap 120. The insulating member 300 can be used to isolate the electrical connection components inside the bottom housing 110 from the end cap 120 to reduce the risk of short circuit. For example, the insulating member 300 may be made of plastic, rubber, etc.

[0071] The bottom shell 110 is a component used to cooperate with the end cap 120 to form the internal environment of the battery cell 12. This internal environment can accommodate the cell assembly 200, electrolyte, and other components. The bottom shell 110 and the end cap 120 can be independent components. An opening can be provided on the bottom shell 110, and the end cap 120 can be used to close the opening to form the internal environment of the battery cell 12. Alternatively, the end cap 120 and the bottom shell 110 can be integrated. Specifically, the end cap 120 and the bottom shell 110 can form a common connecting surface before other components are installed. When it is necessary to encapsulate the interior of the bottom shell 110, the end cap 120 closes the bottom shell 110. The bottom shell 110 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the bottom shell 110 can be determined according to the specific shape and size of the cell assembly 200. The bottom shell 110 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0072] A cell assembly 200 is the component within a single battery cell 12 where electrochemical reactions occur. A single battery cell 12 may contain one or more cell assemblies 200. A cell assembly 200 is primarily formed by winding or stacking positive and negative electrode plates, and typically a separator 230 is provided between the positive electrode plate 210 and the negative electrode plate 220. The portions of the positive and negative electrode plates 210 and 220 containing active material constitute the main body of the cell assembly 200, while the portions of the positive and negative electrode plates 210 and 220 without active material each constitute a tab. The positive electrode tab 212 and the negative electrode tab 222 may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals 121 to form a current loop.

[0073] like Figures 3 to 6 as well as Figure 11 and Figure 12 As shown, in one embodiment of this application, a battery cell 12 is provided. The battery cell 12 includes a housing 100, a cell assembly 200, an insulating member 300, and a buffer member 400. The housing 100 has electrode terminals 121. The cell assembly 200 is disposed inside the housing 100. The cell assembly 200 includes a main body segment 201, a first segment 202, and a tab connected in sequence. The tab is also connected to the electrode terminals 121. The thickness of the first segment 202 is less than the thickness of the main body segment 201. The insulating member 300 is disposed covering the cell assembly 200. The buffer member 400 is disposed on the insulating member 300 and is located between the outer periphery of the first segment 202 and the inner wall of the housing 100.

[0074] The outer casing 100 refers to the outer shell structure of the battery cell 12. The insulating component 300 and the cell assembly 200 are located inside the outer casing 100. The outer casing 100 (such as aluminum alloy, galvanized steel, or aluminum-plastic film) uses a rigid or flexible structure to resist external mechanical impact, compression, or collision to protect the cell assembly (such as electrode sheets and separators). The rigid outer casing 100 (such as the metal casing of a prismatic or cylindrical battery) also provides mechanical support to keep the cell assembly in a stable shape during charging and discharging expansion. In addition, the outer casing 100 forms a sealed space through laser welding or hot-pressing encapsulation technology to maintain the stability of the internal chemical environment of the battery. Furthermore, the material of the outer casing 100 (such as the polypropylene layer of aluminum-plastic film) isolates the internal charge.

[0075] The insulating component 300 covers the outside of the cell assembly 200 and can isolate and insulate the cell assembly 200 from the outer casing 100 to reduce the risk of short circuit. Furthermore, the material of the insulating component 300 needs to have good resistance to electrolyte. Taking the application in a prismatic battery as an example, when the insulating component 300 is not covering the cell assembly 200, it is usually sheet-like and can be folded into a box shape. For example, in the prismatic battery cell 12, the insulating component 300 is usually made of Mylar film. The Mylar film is made of polyester film (PET) and has high insulation. After wrapping the cell assembly 200, it can isolate the cell assembly 200 (positive and negative electrode plates and separator) from the metal outer casing 100 (such as the aluminum or steel casing of a prismatic battery) and reduce the risk of short circuit. For example, in the winding process, there are rounded corners on both sides of the cell. The Mylar film is designed to fit the rounded corners, reducing the risk of the separator being scratched by the edge of the metal casing when the cell is inserted into the casing.

[0076] The buffer 400 refers to a component with a certain degree of elasticity. The buffer 400 can deform under compression and automatically recover after the compression force is removed. The buffer 400 should also be made of a material with good resistance to electrolyte.

[0077] A buffer 400 is disposed on the insulating member 300. The buffer 400 may be disposed on the side of the insulating member 300 near the cell assembly 200, or on the side of the insulating member 300 near the outer casing 100; or the buffer 400 may be disposed on both the side of the insulating member 300 near the cell assembly 200 and the side of the insulating member 300 near the outer casing 100. In other words, with the side of the insulating member 300 near the cell assembly 200 as the inner side and the side of the insulating member 300 near the outer casing 100 as the outer side, the above three embodiments can be understood as the buffer 300 being disposed on the inner side of the insulating member 300, or the buffer 300 being disposed on the outer side of the insulating member 300, or the buffer 300 being disposed on both the inner and outer sides of the insulating member 300. In some embodiments, the insulating member 300 may also include multiple insulating layers, and the buffer 400 may be disposed between the multiple insulating layers.

[0078] The buffer 400 is located between the outer periphery of the first segment 202 and the inner wall of the outer shell 100. The gap between the outer periphery of the first segment 202 and the inner wall of the outer shell 100 is annular. In this case, the buffer 400 is located on one side of the first segment 202 in the circumferential direction; or, the buffer 400 is arranged around the outer periphery of the first segment 202.

[0079] The cell assembly 200 is the core component of the battery cell 12 that enables energy storage and release. It is composed of materials such as a positive electrode, a negative electrode, a separator, and an electrolyte, and is formed into a complete electrochemical unit through specific processes (such as winding or stacking). The cell assembly 200 includes a negative electrode 220, a positive electrode 210, and a separator 230. The battery cell 12 mainly relies on the movement of metal ions between the positive and negative electrode plates to function. The separator 230 can be made of materials such as PP (polypropylene) or PE (polyethylene). In addition, the cell assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to these.

[0080] The positive electrode includes a positive current collector 211 and a positive active material layer 213. The positive active material layer 213 is coated on the surface of the positive current collector 211. The uncoated positive active material layer 213 is usually located at one end of the positive current collector 211 coated with the positive active material layer 213. Generally speaking, the portion of the positive current collector 211 without the positive active material layer 213, away from the positive active material layer 213, serves as the positive electrode tab 212. Taking a lithium-ion battery as an example, the material of the positive current collector 211 can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.

[0081] The negative electrode sheet includes a negative electrode current collector 221 and a negative electrode active material layer 223. The negative electrode active material layer 223 is coated on the surface of the negative electrode current collector 221. The negative electrode current collector 221 without the negative electrode active material layer 223 protrudes from the negative electrode current collector 221 with the negative electrode active material layer 223. The uncoated negative electrode active material layer 223 is usually located at one end of the negative electrode current collector 221 with the negative electrode active material layer 223. Generally speaking, the portion of the negative electrode current collector 221 away from the negative electrode active material layer 223 serves as the negative electrode tab 222. Taking a lithium-ion battery as an example, the material of the negative electrode current collector 221 can be copper, and the negative electrode active material can be carbon or silicon, etc.

[0082] Please see Figure 12 The battery cell assembly 200 has two opposite ends, and is divided into a main body section 201, a first section 202 and a tab section 203 between the two ends of the battery cell. The first section 202 is the part connected between the main body section 201 and the tab section 203.

[0083] In the main body section 201, the active material of the positive and negative electrodes is coated in a flat coating manner. In other words, in the main body section, the thickness of the positive electrode sheet is basically the same, and the thickness of the negative electrode sheet is also basically the same.

[0084] Regarding the boundary line of the first segment 202, taking a prismatic battery as an example, the boundary line between the main body segment 201 and the first segment 202 is taken as the point where the thickness of the negative electrode active material layer 223 begins to decrease. In other words, the first segment 202 includes the thinning area, which refers to the area where the edge of the electrode becomes thinner after processing (meaning the thickness of the active material layer is reduced). Since the tab is bent from a straight state to the target shape (such as L-shaped or U-shaped) by a pressing process, the boundary line between the first segment 202 and the tab segment 203 is usually through this bending point. That is to say, the first segment 202 includes the tab pressing influence area.

[0085] Since the main body segment 201 is coated with a flat coating, and the first segment 202 includes an active material layer thinning area and a current collector without an active material layer, the thickness of the battery cell assembly 200 in the first segment 202 is less than the thickness of the battery cell assembly 200 in the main body segment 201.

[0086] Due to the presence of the thinning area, the thickness of the cell assembly 200 is reduced at the first section 202, resulting in decreased mechanical strength. During charge and discharge cycles, stress concentration is easily generated due to electrode expansion or external pressure, leading to electrode wrinkling or even breakage. Since the tabs are bent from a straight state to the target shape (such as L-shaped or U-shaped) through a pressing process, the insufficient ductility of the metal foil during the pressing process may cause stress concentration in the connection area between the tab and the current collector coated with the active material layer, as well as the periphery of this area (the tab pressing influence area). This can lead to wrinkling or lithium plating problems in the cell assembly 200, and ultimately, cell assembly failure.

[0087] This application provides a buffer 400 on the insulating member 300, positioned between the outer periphery of the first segment 202 and the inner wall of the outer casing 100. When the cell assembly 200 expands, the buffer 400 provides support to the cell assembly 200 at the first segment 202 while slowly releasing space, thus providing buffer protection for the first segment 202 and reducing the risk of cell assembly 200 failure at the first segment 202. Furthermore, compared to providing the buffer 400 across the entire surface area of ​​the battery cell 12, providing it only for the thinned area and the area affected by the tab pressure reduces the internal space occupied by the buffer 400. This allows for more space to be allocated to the cell assembly 200, increasing the energy of the battery cell 12 and improving the thickness margin of the battery cell 12 when used for expansion.

[0088] In some embodiments, the buffer 400 is integrally connected to the insulating member 300 by adhesive bonding or heat fusion.

[0089] The buffer 400 is connected to the insulating component 300 by adhesive or heat fusion. In this embodiment, it means that before the insulating component 300 is wrapped around the cell assembly 200, the buffer 400 is fixed to the insulating component 300 by adhesive or heat fusion. This simplifies the assembly process of the battery cell 12 and makes the connection between the buffer 400 and the insulating component 300 more reliable.

[0090] Adhesion can be achieved using glue or double-sided tape. Thermal fusion bonding refers to a method of melting and bonding materials through heating. For example, a mold is placed on the surface of the insulating component 300, and the material of the buffer component 400 is softened or melted by heating, poured into the mold, and then cooled to solidify, thereby achieving a strong connection between the buffer component 400 and the insulating component 300; alternatively, the buffer component 400 is placed on the insulating component 300, and the buffer component 400 is heated to achieve a thermal fusion bond with the insulating component 300.

[0091] In this embodiment, the buffer 400 is connected to the insulating member 300 by adhesive bonding and heat fusion, which reduces the number of connecting components between the buffer 400 and the insulating member 300. Furthermore, the connection between the buffer 400 and the insulating member 300 by heat fusion improves the reliability of the connection between the buffer 400 and the insulating member 300.

[0092] In some embodiments, please refer to Figure 4 and Figure 5 The buffer 400 is located on the side of the insulating member 300 near the cell assembly 200.

[0093] In other words, the buffer 400 is disposed between the cell assembly 200 and the insulating member 300. In this way, on the one hand, the component formed after assembling the insulating member 300, the buffer 400 and the cell assembly 200 can be easily installed into the housing; on the other hand, the buffer 400 is in direct contact with the active layer material of the cell assembly 200, and by increasing the porosity of the buffer 400, the active layer material at the first section 202 can be better wetted.

[0094] In some embodiments, such as Figure 11 and 12As shown, the battery cell assembly 200 includes a positive electrode 210 and a negative electrode 220. The positive electrode 210 has a first thinning area corresponding to the position of the first segment 202, and the negative electrode 220 has a second thinning area corresponding to the position of the first segment 202. The inner wall surface of the housing 100 where the electrode terminal 121 is located is defined as the first end face. The distance between the first thinning area and the first end face is greater than the distance between the second thinning area and the first end face. The positive electrode 210 includes a first current collector, which includes a first current collector portion 211a corresponding to the main body segment 201. The second current collector 211b corresponding to the first thinning region, the first connecting portion 211c configured as a tab, and the second connecting portion 211d connecting the second current collector 211b and the first connecting portion 211c are covered with a first active material layer. The thickness of the first active material layer on the second current collector 211b decreases from the first current collector 211a toward the second connecting portion 211d. At least a portion of the second connecting portion 211d corresponds to the first segment 202.

[0095] The first thinning region refers to the positive electrode active material layer 213 coated on the positive electrode current collector 211 at this location, whose thickness decreases from the direction of the main body section 201 towards the direction of the tab section 203. Further, as... Figure 11 As shown, the thickness at this location is typically gradually reduced. The second thinning region refers to the negative electrode active material layer 223 coated on the negative electrode current collector 221 at this location, whose thickness decreases from the direction of the main body section towards the tab section. Further, as... Figure 11 As shown, the thickness at this location is typically set to decrease gradually.

[0096] like Figure 11 As shown, the distance between the first thinning area and the first end face is h1, and the distance between the second thinning area and the first end face is h2. At this time, it is equivalent to setting the OH part (Overhang, abbreviated as OH) of the negative electrode region in the first segment 202. The OH part refers to the part of the negative electrode active material layer 223 that extends beyond the positive electrode active material layer 213 in the length or width direction. It is a redundant setting. By increasing the area of ​​the negative electrode active material layer 223, the excessive embedding of lithium ions in the positive electrode active material layer during battery charging can be reduced, thereby reducing the risk of internal short circuit in the battery.

[0097] At the tab end of the battery, dendrite precipitation is likely to occur due to uneven current density distribution. In this embodiment, the OH part is set in the first segment 202. The presence of the OH part can increase the redundant area of ​​the negative electrode at this point, providing more insertion sites for lithium ions, thereby reducing the current density on the surface of the negative electrode 220 and reducing the risk of lithium dendrite precipitation.

[0098] Furthermore, the OH portion is placed in the first section 202. The presence of the OH portion can improve the distribution of electrolyte on the surface of the negative electrode 220, optimize the electric field distribution on the surface of the negative electrode 220, reduce the precipitation of lithium dendrites caused by excessive local current density, and also reduce the problem of uneven electrolyte wetting caused by the thinning area, thereby further reducing the risk of lithium dendrite formation.

[0099] The technical solution of this embodiment can, to a certain extent, reduce the occurrence of dendrites at the edge of the negative electrode 220 caused by the thinning area in the first segment 202 of the battery cell assembly 200.

[0100] In some embodiments, such as Figure 6 and Figure 7 As shown, the battery cell assembly 200 has two opposing first side surfaces 204 and two opposing second side surfaces 205. The area of ​​the first side surface 204 is larger than the area of ​​the second side surface 205. The area of ​​the insulating member 300 corresponding to the first side surface 204 is defined as the first surface area 310, and the area of ​​the insulating member 300 corresponding to the second side surface 205 is defined as the second surface area 320. The buffer member 400 is only located in the first surface area 310 corresponding to the position of the first segment 202.

[0101] Taking a square-shell battery as an example, the first side 204 can be understood as the large surface area of ​​the battery. At this time, the area of ​​the first side 204 is usually several times or more than ten times the area of ​​the second side 205. For example, the area of ​​the first side 204 is two, three, four, five, six, seven, eight or more times the area of ​​the first side 205. The size of the first surface area 310 and the second surface area 320 is basically consistent with the relationship between the first side 204 and the second side 205.

[0102] In this embodiment, since the area of ​​the first side 204 is usually much larger than the area of ​​the second side 205, the buffer 400 is only located on the first side area 310 corresponding to the position of the first segment 202, which can also achieve good protection.

[0103] In some embodiments, such as Figures 4 to 7As shown, the outer casing 100 includes a bottom shell 110 with an opening at one end and an end cap 120 covering the opening; an electrode terminal 121 is disposed on the end cap 120, and the bottom shell 110 and the end cap 120 enclose an installation cavity, in which the battery cell assembly 200 is disposed; the outer casing 100 also includes a top cap 130 disposed in the installation cavity, the top cap 130 being located on the side surface of the end cap 120 facing the battery cell assembly 200; the battery cell assembly 200 passes through the top cap 130, and the electrode tab section 203 is located between the top cap 130 and the end cap 120; the first surface area 310 has a main surface section 311 corresponding to the main body section 201, a first surface section 312 corresponding to the first section 202, and a second surface section 313 corresponding to the electrode tab section 203, a buffer member 400 is disposed on the first surface section 312, and the second surface section 313 is connected to the periphery of the top cap 130 by heat fusion.

[0104] The outer casing 100 includes an end cap 120 and a bottom casing 110. The bottom casing 110 is a cavity with an opening at one end, and the end cap 120 covers the opening. Thus, a sealed mounting cavity is formed between the bottom casing 110 and the end cap 120. The end cap 120 is provided with electrode terminals, and the tabs of the battery cell assembly 200 are connected to the electrode terminals 121 on the end cap 120. The buffer member 400 is located on the insulating member 300 corresponding to the position of the first segment 202. In other words, the buffer member 400 is located in the mounting cavity and close to the opening, while the insulating member 300 needs to be sealed to the top cover 130.

[0105] The top cover 130 not only protects the battery cell assembly 200 from physical damage, but also serves as an isolation layer to prevent external moisture, dust, and corrosive substances from entering the battery cell assembly 200. The top cover 130 is generally provided with clearance space to accommodate the tab section 203.

[0106] For example, such as Figure 5 As shown, the top cover 130 typically includes a top plate 131 and a flange 132 disposed on the top plate 131. The periphery of the top cover 130 can be understood as the flange 132. The second surface section is connected to the periphery of the top cover 130 by heat fusion. In other words, the second surface section 313 is connected to the flange 132 by heat fusion.

[0107] In this embodiment, the provision of the second surface segment 313 increases the connection area between the top cover 130 and the insulating member 300, which facilitates the heat fusion connection between the insulating member 300 and the top cover 130.

[0108] In some embodiments, a first gap exists between the buffer 400 and the top cover 130.

[0109] like Figure 5As shown, the first spacing is d1 in the figure, meaning that the buffer 400 and the top cover 130 are spaced apart, or in other words, the buffer 400 and the top cover 130 are not in contact and are spaced apart. In this application, the buffer 400 and the insulating component 300 are first combined into an insulating assembly, and then the insulating assembly is wrapped around the cell assembly during the assembly of the battery cell 100. The insulating assembly and the cell assembly 200 are then installed onto the bottom shell, and then the top cover 130 is installed onto the bottom shell 100. After that, it is necessary to seal the insulating component 300 and the top cover 130.

[0110] In this embodiment, the buffer 400 and the top cover 130 are spaced apart, which can reduce the impact on the performance of the buffer 400 when the second surface section is heat-sealed with the top cover 130.

[0111] In some embodiments, such as Figure 7 As shown, there is a second gap between the buffer 400 and the second surface area 320.

[0112] The second spacing is as follows Figure 7 As shown in d2, in this embodiment, the insulating component after the insulating component 300 and the buffer component are combined is a box-shaped structure folded from an approximately sheet-like structure to cover the battery cell assembly 200.

[0113] In this embodiment, by setting a second distance between the buffer 400 and the second surface area 320, a certain space can be provided so that the insulating component after the insulating component 300 and the buffer are combined can cover the cell component 200.

[0114] In some embodiments, the compression ratio of the buffer 400 is not less than 50% and not more than 90%.

[0115] In this application, compression ratio refers to the ratio of the compression amount of the buffer 400 to the thickness of the buffer 400 before compression, and compression amount refers to the difference between the thickness of the buffer 400 before compression and the thickness of the buffer 400 after compression.

[0116] In this embodiment, the compression ratio is not less than 50% and not more than 90%, and the compression ratio includes, but is not limited to, 50%, 52%, 55%, 57%, 60%, 63%, 65%, 68%, 70%, 72%, 75%, 77%, 80%, 83%, 85%, 88%, or 90%.

[0117] In this embodiment, the compression rate of the buffer 400 is limited to between 50% and 90%, which can provide support for the first segment 202 of the cell assembly 200 while also having a certain expansion space.

[0118] In some embodiments, the elastic modulus of the buffer 400 is not less than 1.5 MPa and not greater than 70 MPa.

[0119] The elastic modulus refers to the ratio of stress to strain in a material during the elastic deformation stage, reflecting the material's ability to resist elastic deformation. In this embodiment, the elastic modulus of the buffer 400 is not less than 1.5 MPa and not greater than 70 MPa. For example, the elastic modulus of the buffer 400 can be 1.5 MPa, 2 MPa, 5 MPa, 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, 30 MPa, 40 MPa, 50 MPa, 60 MPa, or 70 MPa.

[0120] When the elastic modulus is close to 70 MPa, the buffer 400 has a high resistance to deformation, which can effectively limit the excessive displacement of the cell assembly 200 during expansion and reduce internal structural damage (such as electrode breakage) caused by excessive compression. When the elastic modulus is close to 1.5 MPa, the buffer 400 is more likely to undergo elastic deformation and absorb local stress peaks (such as the instantaneous expansion force when lithium ions are inserted into the electrode). The elastic modulus of the buffer 400 needs to be selected in combination with the volume and energy density of the battery cell 12, which will not be explained in detail here.

[0121] In this embodiment, the elastic modulus of the buffer 400 is not less than 1.5 MPa and not greater than 70 MPa, so that the buffer 400 can better resist elastic deformation and reduce indentation on the battery cell assembly 200.

[0122] In an exemplary embodiment, the compression ratio of the buffer 400 is not less than 50% and not more than 90%, and the elastic modulus of the buffer 400 is not less than 1.5 MPa and not more than 70 MPa.

[0123] In this embodiment, the compression rate is between 50% and 90%, which allows the buffer 400 to deform over a wide range, absorb more energy, and reduce failure caused by excessive compression. The buffer 400, with an elastic modulus ranging from 1.5 to 70 MPa, has both a certain degree of softness and support, so it can both buffer and maintain structural stability when subjected to impact.

[0124] In some embodiments, the material of the buffer 400 is foam, and the porosity of the buffer 400 is not less than 30% and not more than 45%.

[0125] Porosity is a physical quantity that describes the proportion of pore volume to the total volume of a porous material. The porosity of the buffer 400 is not less than 30% and not more than 45%. For example, the porosity of the buffer 400 may include, but is not limited to, 30%, 32%, 35%, 36%, 38%, 40%, 42%, 43%, and 45%.

[0126] In this embodiment, the porosity of the buffer 400 is set to be no less than 30% and no more than 45%; this ensures that the active material layer at the first segment 202 has good wetting properties, reducing the risk of lithium plating due to poor wetting.

[0127] In some embodiments, along the direction of the housing 100 toward the cell assembly 200, the insulating member 300 includes a plurality of insulating layers, and the buffer member 400 is disposed between the plurality of insulating layers.

[0128] Along the direction from the outer casing 100 toward the cell assembly 200, the insulating member 300 includes multiple insulating layers, that is, the insulating member 300 of this application is a composite material, and the buffer member 400 is disposed inside the insulating member 300, located between two insulating layers.

[0129] In this embodiment, the buffer 400 is disposed inside the insulating member 300. At this time, there are fewer restrictions on the material of the buffer 400. For example, when selecting the material of the buffer 400, the requirements for electrolyte resistance can be reduced, and the bonding force between the buffer 400 and the insulating member 300 at the connection surface does not need to be too high, which can reduce the material cost of the buffer 400.

[0130] In some embodiments, the buffer 400 has a plurality of buffer layers 410, at least two of which have different compression ratios; and / or at least two of which have different elastic moduli.

[0131] The buffer 400 has multiple buffer layers 410, which means that the buffer 400 has two or more buffer layers 410. The multiple buffer layers 410 can be arranged in a stacked manner from the insulating member 300 toward the cell assembly 200, or the buffer 400 itself can be wound from the inside to the outside, such as a roll.

[0132] At least two buffer layers 410 have different compression ratios, for example, such as Figure 7 and Figure 8 As shown, there are three buffer layers 410. The buffer layer 410 connected to the insulating member 300 is defined as the first buffer layer 411, the buffer layer 410 furthest from the insulating member 300 is defined as the second buffer layer 412, and the buffer layer 410 located between the first buffer layer 411 and the second buffer layer 412 is defined as the third buffer layer 413. The compression ratios of the first buffer layer 411 and the second buffer layer 412, or the first buffer layer 411 and the third buffer layer 413, or the second buffer layer 412 and the third buffer layer 413 may differ. At least two buffer layers 410 may have different elastic moduli, as described above regarding the case where at least two buffer layers 410 have different compression ratios.

[0133] As the number of charge-discharge cycles increases, the active material layer undergoes cycles of expansion and contraction, causing mechanical fatigue in the battery. If the thinned area lacks sufficient buffer support, it may lead to deformation of the battery casing 100, poor sealing, or even short circuits and other safety hazards. The buffer 400 is designed with multiple layers to provide adaptive support and buffering for the position of the cell assembly 200 corresponding to the first segment 202. The multi-layer design of the buffer 400 provides broader adaptability and more efficient buffering effect by rationally arranging different physical properties (such as hardness, elasticity, density, etc.) in each layer of material. Each layer of material absorbs, disperses, and mitigates impact forces to varying degrees, allowing the overall buffer 400 to react differently according to the magnitude and nature of external impacts, thereby achieving better protection and further reducing deformation of the first segment 202 area of ​​the cell assembly 200 due to pressure changes.

[0134] In some embodiments, at least one buffer layer 410 is made of rubber, and / or at least one buffer layer 410 is made of foam.

[0135] Rubber (a highly elastic polymer material) refers to a highly elastic polymer material with reversible deformation. It is elastic at room temperature, capable of large deformation under small external forces, and returns to its original shape after the external force is removed. Its glass transition temperature (T) is lower than its operating temperature, placing it in a highly elastic state above the operating temperature. In this embodiment, the rubber must also be resistant to the electrolyte; for example, the rubber can be fluororubber, polyurethane rubber, etc. Furthermore, in the embodiments of this application, the rubber mentioned does not include rubber-based foam materials.

[0136] Foam is made from raw materials such as plastics and rubber, with the addition of catalysts, foam stabilizers, foaming agents, and other auxiliary materials. Through physical foaming or cross-linking foaming, a large number of fine foam particles are created within the plastics and rubber, increasing volume and decreasing density. Soft foam is lightweight, flexible, and possesses functions such as cushioning, sound absorption, shock absorption, heat insulation, and filtration. In this embodiment, the selection of foam also requires tolerance to electrolytes; for example, EPDM foam (ethylene propylene diene monomer foam, EPDM being an abbreviation for Ethylene Propylene Diene Monomer Foam) and polyurethane foam are suitable choices.

[0137] Exemplary, Example 1, such as Figure 7 and Figure 8 As shown, at least one buffer layer 410 is made of rubber, which can be any one of the first buffer layer 411, the second buffer layer 412, and the third buffer layer 413.

[0138] In this way, the buffer 400 can withstand the expansion and contraction caused by charging and discharging during battery use without permanent deformation. It can restore its original shape under high pressure and high temperature conditions and maintain effective buffering performance for a long time.

[0139] Exemplary, Example 2, such as Figure 7 and Figure 8 As shown, at least one buffer layer 410 is made of foam, which can be any one of the first buffer layer 411, the second buffer layer 412, and the third buffer layer 413.

[0140] Using foam as the buffer pad for battery cell 12 can effectively absorb the pressure caused by cell expansion during charging and discharging, reducing the risk of damage to the first section 202. Foam is lightweight, flexible, has excellent cushioning and absorption capacity, good shock and vibration resistance, and low cost, making it an economical and efficient cushioning material.

[0141] Exemplary, Example 3, such as Figure 7 and Figure 8 As shown, at least one buffer layer 410 is made of rubber, and at least one buffer layer 410 is made of foam. It can be that the first buffer layer 411 is made of rubber, and the second buffer layer 412 and the third buffer layer 413 are made of foam, or the first buffer layer 411 and the second buffer layer 412 are made of rubber, and the third buffer layer 413 is made of foam. Of course, there can be other cases, which will not be listed here.

[0142] In this embodiment, rubber and foam materials are used in combination. Rubber is suitable for dealing with strong impacts and high pressures, while foam performs well under lightweight and low-intensity impacts. The combination of the two can provide a multi-layered cushioning effect, optimizing impact absorption, vibration isolation and energy dispersion.

[0143] In some embodiments, the buffer 400 is disposed on the side of the insulating member 300 near the cell assembly 200, and a plurality of buffer layers 410 are stacked and arranged from the insulating member 300 toward the cell assembly 200; the material of the buffer layer 410 connected to the insulating member 300 is rubber, and / or the material of the buffer layer 410 farthest from the insulating member 300 is foam.

[0144] In this embodiment, the material of the buffer layer 410 connected to the insulating member 300 may be rubber, or the material of the buffer layer 410 furthest from the insulating member 300 may be foam; or the material of the buffer layer 410 connected to the insulating member 300 may be rubber, and the material of the buffer layer 410 furthest from the insulating member 300 may be foam.

[0145] For example, such as Figure 7 and Figure 8 As shown, there are three buffer layers 410. The buffer layer 410 connected to the insulating member 300 is defined as the first buffer layer 411, that is, the material of the first buffer layer 411 is rubber. The buffer layer 410 that is furthest from the insulating member 300 is defined as the second buffer layer 412, that is, the second buffer layer 412 is foam. The buffer layer 410 located between the first buffer layer 411 and the second buffer layer 412 is the third buffer layer 413. The material of the third buffer layer 413 can be rubber or foam.

[0146] In this embodiment, the use of Mylar film in the insulating component 300 is taken as an example.

[0147] Because rubber typically possesses high elasticity and adhesiveness, it bonds better with the Mylar membrane during the hot-melt process. While foam also has some adhesiveness, its internal structure is relatively loose, and it generally does not bond as tightly to the Mylar membrane as rubber. The hot-melt process for rubber is generally more mature and stable, resulting in better uniformity and consistency in the hot-melt connection between the buffer component 400 and the insulation component 300. In contrast, the hot-melt process for foam is likely more complex because it requires controlling the internal air bubbles and pore structure of the foam, making it more difficult to process.

[0148] Thus, this embodiment can make the connection between the buffer 400 and the insulating part 300 more reliable while reducing the processing difficulty of the buffer 400 and the insulating part 300. Secondly, the material of the buffer layer 410 farthest from the insulating part 300 is foam. The porosity of foam is generally relatively large, which allows the active material layer at the first section 202 to be better wetted. In addition, the weight of foam is relatively light, which can reduce the overall weight and meet the requirements of battery lightweighting.

[0149] In some embodiments, such as Figure 9 As shown, each of the two first surface areas 310 is provided with a buffer member 400 at the position corresponding to the first segment 202; wherein, at least one buffer member 400 has a plurality of buffer parts 420, and the plurality of buffer parts 420 are arranged at intervals along the direction from one second surface area 320 to the other second surface area 320.

[0150] When the cell assembly 200 expands, the speed and extent of its expansion are usually not uniform in all directions. The expansion of the battery may occur more in the central part of the battery. This uneven expansion causes the buffer 400 in different areas to be subjected to different pressures and displacements. For example, the part that expands the most will compress the buffer 400 more, while the part far away from the expansion source will be subjected to less force.

[0151] In this embodiment, by setting the buffer 400 in the form of multiple buffer sections 420, and combining test data, buffer sections 420 with larger compression ratios and elastic moduli are used in the parts with relatively severe expansion, while buffer sections 420 with smaller compression ratios and elastic moduli are used in the parts with relatively mild expansion. This enables the buffer 400 to cope with such uneven stress, and also reduces the amount of material used in the buffer 400.

[0152] In some embodiments, please continue reading Figure 9 The battery cell assembly 200 has a bottom surface, and the area of ​​the insulating member 300 corresponding to the bottom surface is defined as the bottom surface area 330; the orthographic projections of two adjacent buffer parts 420 on the bottom surface area 330 overlap.

[0153] The overlapping portion of the orthographic projections of two adjacent buffer portions 420 on the bottom surface region 330 refers to the fact that, in the assembled cell assembly 200, the orthographic projections of two adjacent buffer portions 420 on the bottom surface region 330 overlap. This allows for a reduction in the material used in the buffer component 400 while ensuring continuous buffer protection along the first direction of the first segment 202 of the cell assembly 200.

[0154] This application also proposes a battery device 10, which includes a battery cell 12 from any of the foregoing embodiments. The specific structure of the battery device 10 is as described in the above embodiments. Since this power device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0155] This application also proposes an electrical device, which includes a battery device 10 from any of the foregoing embodiments. The battery device 10 is used to provide electrical energy. The specific structure of the battery device 10 is the same as described in the above embodiments. Since this electrical device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here. The battery device 10 is used to provide electrical energy, and the electrical device can be an electric vehicle, electric motorcycle, electric bicycle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, include: The outer casing has electrode terminals; A battery cell assembly is disposed within the housing. The battery cell assembly includes a main body segment, a first segment, and a tab segment connected in sequence. The tab segment is also connected to the electrode terminal. The thickness of the first segment is less than the thickness of the main body segment. Insulating element, covering the battery cell assembly; and A buffer element is disposed on the insulating element and located between the outer periphery of the first segment and the inner wall of the outer shell.

2. The battery cell of claim 1, wherein, The buffer component is connected to the insulating component by adhesive bonding or hot-melt connection.

3. The battery cell of claim 1, wherein, The buffer is located on the side of the insulating member closest to the cell assembly; Alternatively, the buffer element may be located on the side of the insulating element closer to the outer casing; Alternatively, along the direction from the outer casing toward the cell assembly, the insulating member includes multiple insulating layers, and the buffer member is disposed between the multiple insulating layers.

4. The battery cell of claim 1, wherein, The battery cell assembly includes a positive electrode and a negative electrode. The positive electrode has a first thinning area corresponding to the position of the first segment, and the negative electrode has a second thinning area corresponding to the position of the first segment. The inner wall surface of the housing where the electrode terminals are located is defined as the first end face, and the distance between the first thinned area and the first end face is greater than the distance between the second thinned area and the first end face. The positive electrode includes a first current collector, which includes a first current collector portion corresponding to the main body segment, a second current collector portion corresponding to the first thinned area, a first connecting portion configured as a tab, and a second connecting portion connecting the second current collector portion and the first connecting portion. The first current collector portion and the second current collector portion are covered with a first active material layer. The thickness of the first active material layer disposed on the second current collector portion decreases from the first current collector portion toward the second connecting portion. At least a portion of the second connecting portion is disposed corresponding to the first segment.

5. The battery cell according to any one of claims 1 to 4, wherein The battery cell assembly has two opposing first sides and two opposing second sides, wherein the area of ​​the first sides is larger than the area of ​​the second sides; The area of ​​the insulating member corresponding to the first side is defined as the first surface area, and the area of ​​the insulating member corresponding to the second side is defined as the second surface area. The buffer member is located only in the first surface area corresponding to the position of the first segment.

6. The battery cell of claim 5, wherein, The housing includes a bottom shell with an opening at one end and an end cap covering the opening; the electrode terminals are disposed on the end cap, the bottom shell and the end cap enclose a mounting cavity, and the battery cell assembly is disposed in the mounting cavity; The housing also includes a top cover disposed in the mounting cavity, the top cover being located on the side surface of the end cover facing the cell assembly; The first surface area has a main surface segment corresponding to the main body segment, a first surface segment corresponding to the first segment, and a second surface segment corresponding to the tab segment. The buffer is disposed on the first surface segment, and the second surface segment is connected to the periphery of the top cover by heat fusion.

7. The battery cell of claim 6, wherein the cathode comprises a lithium metal oxide. There is a first gap between the buffer and the top cover.

8. The battery cell of claim 5, wherein the cathode comprises a lithium metal oxide. There is a second gap between the buffer and the second surface area.

9. The battery cell according to any one of claims 1 to 4, wherein The compression ratio of the buffer is not less than 50% and not more than 90%.

10. The battery cell according to any one of claims 1 to 4, wherein The elastic modulus of the buffer component is not less than 1.5 MPa and not greater than 70 MPa.

11. The battery cell according to any one of claims 1 to 4, wherein The buffer is made of foam, and its porosity is not less than 30% and not more than 45%.

12. The battery cell according to any one of claims 1 to 4, characterized in that, The buffer has multiple buffer layers; At least two of the buffer layers have different compression ratios; and / or, at least two of the buffer layers have different elastic moduli.

13. The battery cell as described in claim 12, characterized in that, At least one of the buffer layers is made of rubber, and / or at least one of the buffer layers is made of foam.

14. The battery cell as described in claim 13, characterized in that, The buffer is disposed on the side of the insulating member close to the cell assembly, and the plurality of buffer layers are stacked and arranged from the insulating member toward the cell assembly; The material of the buffer layer connected to the insulating element is rubber, and / or the material of the buffer layer furthest from the insulating element is foam.

15. The battery cell as described in claim 5, characterized in that, The two first surface areas are respectively provided with the buffer members at the positions corresponding to the first segment, and at least one of the buffer members has multiple buffer parts, which are arranged at intervals along the direction from one second surface area to the other second surface area.

16. The battery cell as described in claim 15, characterized in that, The battery cell assembly has a bottom surface, and the area of ​​the insulating component corresponding to the bottom surface is defined as the bottom surface area; the orthographic projections of two adjacent buffer portions on the bottom surface area overlap.

17. A battery device characterized by comprising: The battery device comprises the battery cell as described in any one of claims 1 to 16.

18. An electrical device, comprising: The electrical device includes the battery device as described in claim 17.

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