Battery monomer, battery device and electric device

Abstract

The utility model relates to a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, an electrode assembly and an end cover assembly, the electrode assembly is arranged in the shell, the electrode assembly comprises a negative pole piece, the negative pole piece is provided with a winding head end and a winding tail end, the negative pole piece comprises a negative active material layer, the negative active material layer comprises a first active material part and a second active material part, and the first active material part is arranged at at least one end of the second active material part in the winding direction; the first active material part extends to the winding head end or the winding tail end in the winding direction, and the size of the first active material part is larger than that of the second active material part in the winding axial direction. The end cover assembly comprises an end cover and an insulating part, the insulating part comprises a main body and a convex body, the convex body is provided with an avoiding concave part, and the first active material part and the avoiding concave part are at least partially overlapped in the winding axial direction. According to the battery monomer provided by the invention, the avoiding concave part can avoid the first active material part to a certain extent.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to battery cells, battery devices, and electrical devices. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Battery cells can include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and rechargeable alkaline zinc-manganese batteries, among others.

[0003] In the development of batteries, how to ensure the reliability of individual battery cells is a technical problem that urgently needs to be solved. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device, which aim to improve the reliability of the battery cell to a certain extent.

[0005] In a first aspect, this application proposes a battery cell, which includes a housing, an electrode assembly, and an end cap assembly. The housing has an opening. The electrode assembly is disposed within the housing and includes a positive electrode and a negative electrode, which are wound along a winding direction. The negative electrode has a winding start end and a winding end end disposed opposite to each other along the winding direction. The negative electrode includes a negative current collector and a negative active material layer disposed on the surface of the negative current collector. The negative active material layer includes a first active material portion and a second active material portion. The first active material portion is disposed at at least one end of the second active material portion along the winding direction and extends to the winding start end or the winding end end along the winding direction. In the winding axis, the size of the first active material portion is larger than the size of the second active material portion. The end cap assembly includes an end cap and an insulating component. The end cap closes the opening. The end cap and the electrode assembly are arranged along the winding axis. The insulating component is disposed on the side of the end cap facing the electrode assembly. The insulating component includes a body and a protrusion. The body is connected to the end cap. The protrusion protrudes from the side of the body facing away from the end cap. The protrusion has a relief recess. In the winding axis, the first active material portion and the relief recess at least partially overlap.

[0006] In the battery cell provided in this application, the protrusion is provided with a relief recess, and the first active material portion at least partially overlaps with the relief recess in the winding axis. The relief recess can, to a certain extent, avoid the first active material portion to accommodate the first active material portion which has a larger size in the winding axis, thereby reducing the interference of the insulating components on the first active material portion. Therefore, it can not only provide a certain degree of restraint for the electrode assembly, but also reduce the risk of squeezing or damaging the negative electrode sheet, thus preventing the electrode assembly from causing a short circuit, thereby improving the reliability of the battery cell.

[0007] According to one embodiment of this application, the end cap assembly includes two protrusions disposed at both ends of the body along a first direction, each protrusion having at least one clearance recess, the first direction being perpendicular to the winding axis.

[0008] In these alternative embodiments, more portions of the insulating component are adapted to the first active material portion, reducing the compression of the first active material portion by the protrusion and improving the risk of short circuit due to electrode assembly breakage.

[0009] According to one embodiment of this application, the avoidance recess extends along a first direction to the edge of the protrusion, the first direction being perpendicular to the winding axis.

[0010] In these alternative embodiments, the clearance recess extends along the first direction to the edge of the protrusion, providing more clearance space for the first active material portion in the first direction when assembled with the end cap assembly, thus greatly reducing the possibility of installation interference in the first direction.

[0011] According to one embodiment of this application, the protrusion includes a first wall and a second wall connected to the first wall. The first wall is disposed on the side of the protrusion away from the end cap along the winding axis, and the second wall is disposed on the side of the protrusion close to the first active material portion along a first direction. The first wall has a relief recess that extends to the second wall.

[0012] According to one embodiment of this application, the second wall is provided with a hole that penetrates the second wall along a first direction, and the hole is spaced apart from the avoidance recess.

[0013] In these alternative embodiments, since the holes and the clearance recesses are spaced apart, the second wall still has a certain supporting capacity, which satisfies its own structural strength and reduces the excessive weakening of the load-bearing capacity of the second wall by the presence of the clearance recesses and holes.

[0014] According to one embodiment of this application, the protrusion includes a plurality of clearance recesses, which are spaced apart along a second direction perpendicular to the winding axis.

[0015] In these alternative embodiments, the first active material portion is configured to fit different regions of the electrode assembly, thereby making the insulating component more compatible with the structure of the electrode assembly.

[0016] According to one embodiment of this application, the negative electrode active material layer includes two first active material portions, one of which extends along the winding direction to the beginning of the winding, and the other extending along the winding direction to the end of the winding. A plurality of clearance recesses include a first clearance recess and a second clearance recess. The first clearance recess overlaps with both the first active material portion located at the beginning of the winding and the first active material portion located at the end of the winding, while the second clearance recess overlaps only with the first active material portion located at the end of the winding.

[0017] In these alternative embodiments, the shape and size of the protrusion can be better adapted to the first active material portion, and a tight fit between the electrode assembly and the insulating component is achieved, reducing gaps or looseness caused by structural mismatch.

[0018] According to one embodiment of this application, in a first direction, the size of the first clearance recess is greater than or equal to the size of the second clearance recess, and the first direction is perpendicular to the second direction and around the axial direction.

[0019] In these alternative embodiments, in the first direction, the size of the first clearance recess is greater than or equal to the size of the second clearance recess, such that the first clearance recess has sufficient space to avoid the first active material portion, further reducing interference to the electrode assembly.

[0020] According to one embodiment of this application, the second clearance recess is located on both sides of the first clearance recess along the second direction.

[0021] According to one embodiment of this application, a battery cell includes a plurality of electrode assemblies stacked along a second direction, wherein a second clearance recess overlaps with the first active material portion located at the winding end of two adjacent electrode assemblies.

[0022] In these alternative embodiments, the first active material portion at the winding end of two adjacent electrode assemblies overlaps with the same second clearance recess, achieving a more compact internal space layout while satisfying reasonable clearance of the first active material portion.

[0023] According to one embodiment of this application, the plurality of clearance recesses include a plurality of first clearance recesses and a plurality of second clearance recesses, and the plurality of first clearance recesses and the plurality of second clearance recesses are alternately arranged along a second direction.

[0024] In these alternative embodiments, the first and second clearance recesses are alternately arranged along the second direction, so that the winding start and winding end of each electrode assembly and the overall distribution of the multiple electrode assemblies are more uniform in the direction of electrode assembly stacking.

[0025] According to one embodiment of this application, in a first direction, the projection of the avoidance recess covers the first active material portion, and the avoidance recess is at least partially arc-shaped.

[0026] In these alternative embodiments, the avoidance recess is at least partially arc-shaped, which can avoid the first active material portion to a greater extent, further reducing the compression on the counter electrode assembly.

[0027] According to one embodiment of this application, the electrode assembly includes a flat region and a bent region connected to both ends of the flat region. The protrusion overlaps with both the flat region and the bent region, and a portion of the avoidance recess overlaps with a first active material portion disposed in the flat region.

[0028] According to one embodiment of this application, the first active material portion is wound 1 to 10 turns in the winding direction.

[0029] In these alternative embodiments, this arrangement is advantageous in increasing the arrangement area of ​​the first active material portion, while reducing the space occupied by the negative electrode sheet, reducing the overall volume and weight of the battery cell, increasing energy density, and improving the reliability of the battery cell.

[0030] Secondly, this application provides a battery device including the aforementioned battery cell.

[0031] According to one embodiment of this application, the insulating component is located on the underside of the electrode assembly.

[0032] In these alternative embodiments, the insulating component is located below the electrode assembly. This can be understood as the battery cell being inverted so that the insulating component is located below the electrode assembly, and the insulating component is used to support part of the electrode assembly.

[0033] Thirdly, this application provides an electrical device, including a battery cell or a battery device as described above, wherein the battery cell or battery device is used to store or provide electrical energy.

[0034] 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

[0035] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0036] Figure 1 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application;

[0037] Figure 2 This is an exploded view of a battery device provided in an embodiment of this application;

[0038] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application;

[0039] Figure 4 This is a partial structural schematic diagram of the electrode assembly of a battery cell provided in an embodiment of this application;

[0040] Figure 5 This is a cross-sectional view of the electrode assembly of a battery cell provided in an embodiment of this application;

[0041] Figure 6 This is an exploded view of the end cap assembly of a battery cell provided in an embodiment of this application;

[0042] Figure 7 This is a schematic diagram of the structure of the end cap assembly of a battery cell provided in an embodiment of this application;

[0043] Figure 8 This is a schematic diagram of the structure of the insulating component of a battery cell provided in an embodiment of this application;

[0044] Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure of the insulating component at point a is shown in one embodiment.

[0045] Figure 10 This is a schematic diagram of the structure of the insulating component of a battery cell provided in another embodiment of this application;

[0046] Figure 11 This is a schematic diagram of the structure of the insulating component of a battery cell provided in another embodiment of this application;

[0047] Figure 12 This is a schematic diagram of the structure of the insulating component of a battery cell provided in another embodiment of this application;

[0048] Figure 13 This is a schematic diagram of the structure of the avoidance recess of a battery cell provided in an embodiment of this application;

[0049] Figure 14 This is a schematic diagram of the avoidance recess of a battery cell provided in another embodiment of this application.

[0050] The accompanying drawings may not be drawn to scale.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1000, vehicles;

[0053] 100. Battery assembly; 200. Controller; 300. Motor;

[0054] 1a. Battery module; 1b. First housing; 1c. Second housing;

[0055] 10. Battery cells;

[0056] 1. Shell; 11. Opening;

[0057] 2. Electrode assembly; 21. Positive electrode sheet; 22. Negative electrode sheet; 22a. Winding start end; 22b. Winding end end; 221. Negative current collector; 222. Negative active material layer; 2221. First active material section; 2222. Second active material section; 2a. Straight region; 2b. Bending region;

[0058] 3. End cap assembly; 31. End cap; 32. Insulating component; 321. Body; 322. Protrusion; 3221. First wall; 3222. Second wall; 3223. Hole; 323. Recess; 3231. First recess; 3232. Second recess;

[0059] x, first direction; y, second direction; M, winding direction; L, winding axis. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0061] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application 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 description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0062] In this application, the reference to "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 in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0063] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0064] 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 three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0065] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0066] In this application, "multiple" means two or more (including two).

[0067] Currently, judging from market trends, the application of batteries is becoming increasingly widespread. Batteries 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.

[0068] A battery device typically refers to a single physical module comprising multiple battery cells to provide higher voltage and capacity. A battery cell can be the smallest unit that makes up a battery device.

[0069] In related technologies, during the winding process of electrode assemblies, the electrode ends need to be separated from the roll by cutting. However, the cut electrode ends lack tension and tend to shift, resulting in defects in the overhang region (i.e., the area where the negative and positive active material layers do not overlap). This leads to partial non-overlapping of the positive and negative electrode sheets, causing ion deposition and internal short circuits in the battery cell. Therefore, increasing the dimension of the negative active material layer along the winding axis of the negative electrode sheet allows for more offset, reducing the likelihood that insufficient tension at the cut end of the negative electrode sheet will prevent it from completely covering the positive electrode sheet. However, this design can cause the insulating components of the end cap assembly to compress the negative electrode sheet, leading to electrode assembly insertion and a risk of short circuits, thus reducing the reliability of the battery cell. The above statements are for informational purposes only and do not necessarily constitute prior art.

[0070] The battery cell described in this application is applicable to batteries and electrical devices that use batteries. This battery cell can be used, but is not limited to, batteries, and can also be used in products such as vehicles, aircraft, ships, electronic devices, and power tools, thereby improving the reliability of these products.

[0071] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, among others. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0072] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device according to an embodiment of this application.

[0073] See Figure 1As shown, one embodiment of this application provides a vehicle 1000. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. In one embodiment of this application, the vehicle 1000 may include a motor 300, a controller 200, and a battery device 100. The controller 200 is used to control the battery device 100 to supply power to the motor 300. The motor 300 is connected to the wheels via a transmission mechanism, thereby driving the vehicle 1000. The battery device 100 can serve as the driving power source for the vehicle 1000, replacing or partially replacing gasoline or natural gas to provide driving power to the vehicle 1000. In one example, the battery device 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to supply power to the vehicle 1000. In one example, the battery device 100 can serve as the operating power source for the vehicle 1000's electrical system. For example, the battery device 100 can be used to meet the power needs of the vehicle 1000 during startup, navigation and operation.

[0074] Please refer to Figure 2 , Figure 2 An exploded view of a battery device 100 provided in some embodiments of this application.

[0075] In some embodiments, the battery device 100 may include one or more battery cell assemblies for providing voltage and capacity.

[0076] A battery cell assembly may include multiple battery cells ( Figure 2 (Not shown) Multiple battery cells are connected in series, parallel, or mixed connection through a busbar. Mixed connection refers to multiple battery cells being connected in both series and parallel.

[0077] A battery cell can be a rechargeable battery cell, which refers to a battery cell that can be recharged after being discharged to activate the active materials and continue to be used.

[0078] As an example, a single battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0079] As an example, a battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0080] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module 1a, which is formed by arranging and fixing multiple battery cells to form an independent module. As an example, a battery module 1a can be formed by bundling multiple battery cells together with cable ties.

[0081] In some embodiments, the battery device 100 may be a battery pack, which includes a housing and one or more battery cell assemblies housed within the housing. As an example, the battery cell assembly may be a battery module 1a, which can be housed within the housing by securing the battery module 1a to the housing. Alternatively, the battery cell assembly may be housed within the housing by directly securing multiple battery cells to the housing.

[0082] In some embodiments, the housing is used to house individual battery cells, and the housing can have various structures.

[0083] In some embodiments, the housing may include a first housing 1b and a second housing 1c, which overlap each other, and together define a receiving space for accommodating a single battery cell. The second housing 1c may be a hollow structure with one open end, and the first housing 1b may be a plate-like structure, with the first housing 1b covering the open side of the second housing 1c so that the first housing 1b and the second housing 1c together define the receiving space. Alternatively, both the first housing 1b and the second housing 1c may be hollow structures with one open side, with the open side of the first housing 1b covering the open side of the second housing 1c. Of course, the housing formed by the first housing 1b and the second housing 1c can be of various shapes, such as a cylinder, a cuboid, etc.

[0084] In some embodiments, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are respectively connected to the frame, forming an enclosed space inside the enclosure to house the individual battery cells. As an example, the frame may include multiple side beams.

[0085] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0086] In some embodiments, the battery device 100 may be an energy storage device.

[0087] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, energy storage devices can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours.

[0088] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0089] Figure 3 This is an exploded view of a single battery cell provided in an embodiment of this application.

[0090] In some embodiments, there are multiple battery cells 10, which are first connected in series, parallel, or mixed to form a battery module 1a. The multiple battery modules 1a are then connected in series, parallel, or mixed to form a whole and housed in a housing.

[0091] Multiple battery cells 10 in battery module 1a can be electrically connected through a busbar to achieve parallel, series, or mixed connection of the multiple battery cells 10 in battery module 1a. There can be one or more busbars, and each busbar is used to electrically connect at least two battery cells 10.

[0092] This application provides a battery cell 10, which includes a housing and an electrode assembly 10 housed within the housing.

[0093] In some embodiments, the outer casing may be a steel casing, an aluminum casing, or a composite metal casing (such as a copper-aluminum composite casing).

[0094] The outer shell can be a hollow structure, with an internal cavity for accommodating the electrode assembly 10 and the electrolyte.

[0095] In some embodiments, the casing of the battery cell 10 is a cylindrical casing, a square casing, a prismatic casing, or a casing of other shapes.

[0096] In some embodiments, the housing includes a housing and an end cap, the housing having an opening and the end cap being connected to the housing and covering the opening;

[0097] The housing is a component used to fit the end cap to form the internal cavity of the battery cell 10, which can be used to accommodate the electrode assembly 10, electrolyte, and other components.

[0098] The housing and end cap can be separate components. For example, an opening can be provided on the housing, and the end cap 31 can be used to close the opening to form an internal cavity for the battery cell 10.

[0099] The housing can be of various shapes and sizes, such as cuboid or cylindrical. Specifically, the shape of the housing can be determined according to the specific shape and size of the electrode assembly 10. The housing can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0100] The shape of the end cap can be adapted to the shape of the housing to fit the housing. The material of the end cap can be the same as or different from that of the housing. Optionally, the end cap can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.), so that the end cap is not easily deformed when subjected to compression and impact, so that the battery cell 10 can have higher structural strength and improve reliability.

[0101] The end caps are attached to the housing by welding, bonding, snap-fitting, or other means.

[0102] The housing may be open at one end or at both ends. In some examples, the housing may be a structure with an opening on one side, with one end cap fitting over the housing. In other examples, the housing may be a structure with openings on both sides, with two end caps fitting over the two openings of the housing, respectively.

[0103] Electrode assembly 10 is a component in the battery cell 10 where electrochemical reactions occur. The housing may contain one or more electrode assemblies 10.

[0104] In some embodiments, the electrode assembly 10 includes a positive electrode, a negative electrode, and a separator, wherein the positive electrode and the negative electrode have opposite polarities, and the separator separates the positive electrode and the negative electrode.

[0105] At least a portion of the separator is located between the positive and negative electrode plates. During the charging and discharging process of the battery cell 10, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrode plates. The separator, positioned between the positive and negative electrode plates, serves to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0106] In some embodiments, the positive electrode sheet may include a positive current collector and a layer of positive active material disposed on at least one surface of the positive current collector.

[0107] As an example, the positive current collector has two surfaces opposite each other in thickness, and the positive active material layer is disposed on either or both of the opposite surfaces of the positive current collector.

[0108] As an example, the positive current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0109] As an example, the positive electrode active material layer includes a positive electrode active material, which may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.8 Co 0.15 Al 0.05At least one of O2 and its modified compounds. Modified compounds refer to substances obtained by modification methods such as doping or coating based on the above-mentioned substances.

[0110] In some embodiments, the negative electrode may include a negative current collector.

[0111] As an example, the negative electrode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, nickel alloys, titanium, or silver. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0112] As an example, the negative electrode sheet may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0113] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0114] As an example, the negative electrode active material layer includes a negative electrode active material, which may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0115] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0116] In some embodiments, the separator includes a separator membrane. The separator membrane in this application can be any known porous membrane with good chemical and mechanical stability.

[0117] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different.

[0118] Inorganic particle coating, organic particle coating, or organic / inorganic composite coating can also be applied to the surface of the separator.

[0119] The separator can be a single component located between the positive and negative electrodes, or it can be attached to the surface of the positive or negative electrode.

[0120] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrode plates, serving both to transport ions and to isolate the positive and negative electrodes.

[0121] In some embodiments, the battery cell 10 further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte used in this application can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0122] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0123] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0124] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0125] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the battery cell, such as additives that improve the overcharge / fast charge performance of the battery cell, additives that improve the high-temperature performance of the battery cell, and additives that improve the low-temperature performance of the battery cell.

[0126] In some embodiments, the gel electrolyte comprises a polymer as a backbone network and can be used in conjunction with an ionic liquid-lithium salt.

[0127] In some embodiments, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0128] As an example, the polymers of polymeric solid electrolytes may include polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids, cellulose, etc.

[0129] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0130] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0131] In some embodiments, the electrode assembly 10 is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0132] In some embodiments, the positive current collector may include a positive tab, and the negative current collector may include a negative tab. The positive and negative tabs can be used to transmit current. As an example, at least a portion of the positive tab is not coated with a positive active material layer, and at least a portion of the negative tab is not coated with a negative active material layer.

[0133] See Figures 4 to 6 , Figure 4 This is a partial structural schematic diagram of the electrode assembly of a battery cell provided in an embodiment of this application; Figure 5 This is a cross-sectional view of the electrode assembly of a battery cell provided in an embodiment of this application; Figure 6 This is an exploded view of the end cap assembly of a battery cell provided in an embodiment of this application; Figure 7 This is a schematic diagram of the end cap assembly of a battery cell provided in an embodiment of this application.

[0134] like Figures 3 to 7As shown, this application proposes a battery cell, which includes a housing 1, an electrode assembly 2, and an end cap assembly 3. The housing 1 has an opening 11. Electrode assembly 2 is disposed within housing 1. Electrode assembly 2 includes a positive electrode 21 and a negative electrode 22. The positive electrode 21 and the negative electrode 22 are wound along the winding direction M. The negative electrode 22 has a winding start end 22a and a winding end end 22b disposed opposite to each other along the winding direction M. The negative electrode 22 includes a negative current collector 221 and a negative active material layer 222 disposed on the surface of the negative current collector 221. The negative active material layer 222 includes a first active material portion 2221 and a second active material portion 2222. The first active material portion 2221 is disposed at at least one end of the second active material portion 2222 along the winding direction M, and the first active material portion 2221 extends along the winding direction M to the winding start end 22a or the winding end end 22b. In the winding axis L, the size of the first active material portion 2221 is larger than the size of the second active material portion 2222. The end cap assembly 3 includes an end cap 31 and an insulating component 32. The end cap 31 closes the opening 11. The end cap 31 and the electrode assembly 2 are arranged along the winding axis L. The insulating component 32 is disposed on the side of the end cap 31 facing the electrode assembly 2. The insulating component 32 includes a main body 321 and a protrusion 322. The main body 321 is connected to the end cap 31. The protrusion 322 protrudes from the side of the main body 321 facing away from the end cap 31. The protrusion 322 is provided with a relief recess 323. Along the winding axis L, the first active material portion 2221 and the relief recess 323 at least partially overlap.

[0135] In some examples, the electrode assembly 2 is a wound structure, with the positive electrode 21 and the negative electrode 22 wound into at least part of the wound structure.

[0136] In some examples, the shape of electrode assembly 2 can be cylindrical, flat, or polygonal, etc.

[0137] In some examples, the negative electrode active material layer 222 may cover one side surface of the negative electrode current collector 221 along its own thickness direction. In other examples, the negative electrode sheet 22 includes two negative electrode active material layers 222, which are respectively disposed on both sides of the negative electrode current collector 221 along its own thickness direction.

[0138] Specifically, the positive electrode 21 includes a positive current collector and a positive active material layer disposed on the surface of the positive current collector.

[0139] In some examples, the positive electrode active material layer may cover one side of the positive electrode current collector along its own thickness direction. In other examples, the positive electrode 21 includes two positive electrode active material layers, which are respectively disposed on both sides of the positive electrode current collector along its own thickness direction.

[0140] The negative electrode active material layer 222 includes a first active material portion 2221 and a second active material portion 2222, and the first active material portion 2221 is connected to at least one end of the second active material portion 2222 along the winding direction M.

[0141] For example, along the winding direction M, a first active material portion 2221 and a second active material portion 2222 are sequentially provided. That is, the first active material portion 2221 can be wound from the winding start end 22a, and after being wound to a preset number of turns, the second active material portion 2222 can be wound to the winding end end 22b.

[0142] For example, along the winding direction M, a second active material portion 2222 and a first active material portion 2221 are provided in sequence. That is, the second active material portion 2222 can be wound from the winding start end 22a. After being wound to a preset number of turns, the first active material portion 2221 starts to be wound and is wound to the winding end end 22b.

[0143] For example, along the winding direction M, a first active material portion 2221, a second active material portion 2222 and a first active material portion 2221 are sequentially provided. That is, a first active material portion 2221 can be wound from the winding start end 22a and wound to a preset number of turns. Then, the second active material portion 2222 can be wound and wound to a preset number of turns. Then, the other first active material portion 2221 can be wound and wound to the winding end end 22b.

[0144] Along the winding axis L, the size of the first active material portion 2221 of the negative electrode 22 is larger than the size of the second active material portion 2222. The first active material portion 2221 has more offset margin, thereby reducing the possibility that the negative electrode active material layer 222 may not completely cover the positive electrode active material layer of the positive electrode 21 when there is offset at the beginning of winding 22a or the end of winding 22b. This allows the negative electrode active material layer 222 to provide intercalation space for ions extracted from the positive electrode active material layer, reducing the risk of ion deposition and improving reliability.

[0145] In some examples, along the winding axis L, the two ends of the first active material portion 2221 located at the winding start end 22a extend beyond the positive electrode plate 21 located at the winding start end 22a.

[0146] In other examples, along the winding axis L, the two ends of the first active material portion 2221 located at the winding end 22b extend beyond the positive electrode 21 located at the winding end 22b.

[0147] In some other examples, along the winding axis L, both ends of the first active material portion 2221 located at the beginning of the winding 22a and both ends of the first active material portion 2221 located at the end of the winding 22b extend beyond the positive electrode plate 21.

[0148] Optionally, in the winding axis L, the two ends of the second active material layer extend beyond the two ends of the positive electrode 21 opposite to it in the winding direction M.

[0149] The end cap assembly 3 is a component used to cooperate with the housing 1 to form the internal cavity of the battery cell. The formed internal cavity can be used to accommodate the electrode assembly 2 and other components.

[0150] An insulating component 32 is located on the side of the end cap 31 facing the electrode assembly 2 to insulate and separate the end cap 31 from the electrode assembly 2. The insulating component 32 serves to provide insulation between the end cap 31 and the electrode assembly 2, thereby improving the safety performance of the battery cell. The insulating component 32 is made of an insulating material, such as plastic or PVC.

[0151] For example, the insulating component 32 and the end cap 31 can be connected by means of adhesive, snap-fit ​​or threaded connection.

[0152] The insulating component 32 may include one or more protrusions 322, which are spaced apart on the main body 321.

[0153] The main body 321 and the end cap 31 are stacked along the thickness direction. The protrusion 322 protrudes from the surface of the main body 321 away from the end cap 31.

[0154] In some examples, along the winding axis L, the projection of the protrusion 322 onto the electrode assembly 2 at least partially overlaps with the first active material portion 2221.

[0155] The protrusion 322 is provided with a relief recess 323, and in the winding axis L, the first active material portion 2221 and the relief recess 323 at least partially overlap. The relief recess 323 can, to a certain extent, avoid the first active material portion 2221.

[0156] Along the winding axis L, the surface of the protrusion 322 facing the electrode assembly 2 is provided with an inwardly recessed clearance recess 323.

[0157] In some examples, the recess 323 includes a groove or a recess 3223.

[0158] In some examples, the recess 323 structure can be a rectangular structure, a rhomboid structure, a triangular structure, a cylindrical structure, a semi-circular structure, or other shapes.

[0159] In the battery cell provided in this application, the protrusion 322 is provided with a relief recess 323. In the winding axis L, the first active material portion 2221 and the relief recess 323 at least partially overlap. The relief recess 323 can, to a certain extent, avoid the first active material portion 2221 to adapt to the first active material portion 2221 which has a larger size in the winding axis L, thereby reducing the interference of the insulating component 32 on the first active material portion 2221. Therefore, it can not only provide a certain binding effect on the electrode assembly 2, but also reduce the risk of squeezing or damaging the negative electrode sheet 22, thus preventing the electrode assembly 2 from causing a short circuit, thereby improving the reliability of the battery cell.

[0160] See also Figures 8 to 11 , Figure 8 This is a schematic diagram of the structure of the insulating component of a battery cell provided in an embodiment of this application; Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure of the insulating component at point a is shown in one embodiment. Figure 10 This is a schematic diagram of the structure of the insulating component of a battery cell provided in another embodiment of this application; Figure 11 This is a schematic diagram of the insulating component of a battery cell provided in another embodiment of this application.

[0161] According to one embodiment of this application, such as Figures 7 to 11 As shown, the end cap assembly 3 includes two protrusions 322, which are disposed at both ends of the main body 321 along the first direction x. Each protrusion 322 is provided with at least one clearance recess 323. The first direction x is perpendicular to the winding axis L.

[0162] In some examples, at least a portion of the end of the protrusion 322 away from the body 321 presses against the electrode assembly 2.

[0163] In some examples, the end cap assembly 3 includes two protrusions 322, each protrusion 322 having a relief recess 323, and the relief recesses 323 are correspondingly provided in the first direction x.

[0164] Specifically, the number of clearance recesses 323 provided on the two protrusions 322 may be equal or unequal.

[0165] In these alternative embodiments, the insulating component 32 is adapted to the first active material portion 2221 in more places, reducing the compression of the first active material portion 2221 by the protrusion 322 and improving the risk of short circuit due to damage to the electrode assembly 2.

[0166] According to one embodiment of this application, the recess 323 extends along a first direction x to the edge of the protrusion 322, the first direction x being perpendicular to the winding axis L.

[0167] The recess 323 extends along the first direction x to the edge of the protrusion 322 to increase the size of the recess 323 along the first direction x, thereby forming a larger receiving space.

[0168] For example, the protrusion 322 has two opposing sidewalls along the first direction x, and the relief recess 323 provided on the protrusion 322 extends along the first direction x toward the two sidewalls.

[0169] Optionally, the insulating component 32 includes two protrusions 322, which are disposed at both ends of the main body 321 along the first direction x. The two protrusions 322 include a first protrusion 322 and a second protrusion 322. In the first direction x, the clearance recess 323 of the first protrusion 322 extends to the edge of the first protrusion 322 near the second protrusion 322, and the clearance recess 323 of the second protrusion 322 extends to the edge of the second protrusion 322 near the first protrusion 322.

[0170] Optionally, the insulating component 32 includes two protrusions 322, and the first direction x is the arrangement direction of the two protrusions 322.

[0171] In these alternative embodiments, the clearance recess 323 extends along the first direction x to the edge of the protrusion 322, which provides more clearance space for the first active material portion 2221 in the first direction x when assembled with the end cap assembly 3, thereby greatly reducing the possibility of installation interference in the first direction x.

[0172] According to one embodiment of this application, such as Figure 7 and Figure 8 As shown, the protrusion 322 includes a first wall 3221 and a second wall 3222 connected to the first wall 3221. The first wall 3221 is disposed on the side of the protrusion 322 away from the end cap 31 along the winding axis L. The second wall 3222 is disposed on the side of the protrusion 322 close to the first active material portion 2221 along the first direction x. The first wall 3221 is provided with a relief recess 323 and the relief recess 323 extends to the second wall 3222.

[0173] In some examples, the insulating component 32 includes two protrusions 322 disposed at both ends of the main body 321 along the first direction x. The two protrusions 322 include a first protrusion 322 and a second protrusion 322. Both the first protrusion 322 and the second protrusion 322 include a first wall 3221 and a second wall 3222 connected to the first wall 3221. The first wall 3221 is disposed on the side of the protrusion 322 away from the end cap 31 along the winding axis L. The second wall 3222 is disposed on the side of the protrusion 322 close to the first active material portion 2221 along the first direction x. The second wall 3222 of the first protrusion 322 and the second wall 3222 of the second protrusion 322 are disposed opposite to each other in the first direction x.

[0174] In some examples, along the winding axis L, the height of the first wall 3221 is greater than or equal to the depth of the relief recess 323.

[0175] In some examples, along the winding axis L, the height of the second wall 3222 is greater than the depth of the clearance recess 323.

[0176] According to one embodiment of this application, such as Figure 7 As shown, the second wall 3222 is provided with a hole 3223, which penetrates the second wall 3222 along the first direction x, and the hole 3223 is spaced apart from the relief recess 323.

[0177] For example, the protrusion 322 is provided with a channel penetrating the protrusion 322, and the channel forms a hole 3223 in the second wall 3222. The channel can serve as a passage for gas flow in the event of thermal runaway of a battery cell, accelerating the discharge of gas from the battery cell.

[0178] In these alternative embodiments, since the hole 3223 and the relief recess 323 are spaced apart, the second wall 3222 still has a certain supporting capacity, which satisfies its own structural strength and reduces the excessive weakening of the bearing capacity of the second wall 3222 by the presence of the relief recess 323 and the hole 3223.

[0179] See also Figures 12 to 14 , Figure 12 This is a schematic diagram of the structure of the insulating component of a battery cell provided in another embodiment of this application; Figure 13 This is a schematic diagram of the structure of the avoidance recess of a battery cell provided in an embodiment of this application; Figure 14 This is a schematic diagram of the avoidance recess of a battery cell provided in another embodiment of this application.

[0180] According to one embodiment of this application, such as Figures 12 to 14 As shown, the protrusion 322 includes a plurality of clearance recesses 323, which are spaced apart along a second direction y, and the second direction y is perpendicular to the winding axis L.

[0181] In some examples, the insulating member 32 includes two protrusions 322, each protrusion 322 having a plurality of clearance recesses 323, the number of clearance recesses 323 on each protrusion 322 being the same; alternatively, the number of clearance recesses 323 on each protrusion 322 being different.

[0182] In some examples, the protrusion 322 includes a plurality of clearance recesses 323, the plurality of clearance recesses 323 including clearance recess one and clearance recess two, the clearance recess one and clearance recess two being spaced apart along a second direction y.

[0183] Optionally, the distances along the second direction y for the first and second avoidance recesses are different.

[0184] Optionally, the distances along the first direction x for the first avoidance recess and the second avoidance recess are different.

[0185] In some examples, the protrusion 322 includes a plurality of clearance recesses, and the plurality of clearance recesses 323 include a plurality of clearance recess one and a plurality of clearance recess two. In the second direction y, at least one clearance recess two is provided between two adjacent clearance recess one. The clearance recess one and the clearance recess two have different structures.

[0186] In some examples, the protrusion 322 includes a plurality of clearance recesses 323, which are spaced apart along the second direction y, and at least one portion of the clearance recess 323 overlaps with the second active material layer in the winding axis L.

[0187] In these alternative embodiments, the first active material portion 2221 of different regions of the electrode assembly 2 is configured to better match the structure of the insulating component 32 with that of the electrode assembly 2.

[0188] According to one embodiment of this application, such as Figure 13 As shown, the negative electrode active material layer 222 includes two first active material portions 2221, one of which extends along the winding direction M to the winding start end 22a, and the other extends along the winding direction M to the winding end end 22b. A plurality of clearance recesses 323 include a first clearance recess 3231 and a second clearance recess 3232. The first clearance recess 3231 overlaps with both the first active material portion 2221 located at the winding start end 22a and the first active material portion 2221 located at the winding end 22b, while the second clearance recess 3232 overlaps only with the first active material portion 2221 located at the winding end 22b.

[0189] The negative electrode active material layer 222 includes two first active material portions 2221 and a second active material portion 2222. The first active material portion 2221, the second active material portion 2222, and the first active material portion 2221 are sequentially arranged along the winding direction M. Specifically, one first active material portion 2221 is wound from the winding start end 22a, and the other first active material portion 2221 is wound to the winding end end 22b. The clearance recess 323 overlaps with at least one of the first active material portion 2221 extending along the winding direction M to the winding start end 22a and the first active material portion 2221 extending along the winding direction M to the winding end end 22b.

[0190] In some examples, in the first direction x, a portion of the first active material portion 2221 extending along the winding direction M to the winding end 22b overlaps with the first active material portion 2221 extending along the winding direction M to the winding beginning 22a, and another portion of the first active material portion 2221 extending along the winding direction M to the winding end 22b overlaps with the first active material portion 2221 extending along the winding direction M to the winding beginning 22a.

[0191] Optionally, from the starting end to the ending end 22b of the winding, the negative electrode sheet 22 includes a plurality of straight portions and a plurality of bent portions, which are alternately arranged. In the first direction x, the straight portions and bent portions of the first active material portion 2221 located at the starting end 22a of the winding overlap at least partially with the bent portions of the first active material portion 2221 located at the ending end 22b of the winding, while the straight portions of the first active material portion 2221 located at the starting end 22a and the first active material portion 2221 located at the ending end 22b of the winding do not overlap.

[0192] For example, the plurality of clearance recesses 323 include a first clearance recess 3231 and a second clearance recess 3232. The first clearance recess 3231 overlaps at least partially with the straight portion and the bent portion of the first active material portion 2221 located at the winding start end 22a and the bent portion of the first active material portion 2221 located at the winding end end 22b. The second clearance recess 3232 overlaps with the straight portion of the first active material portion 2221 located at the winding end end 22b.

[0193] For example, the plurality of clearance recesses 323 include a first clearance recess 3231 and a second clearance recess 3232. The first clearance recess 3231 overlaps at least partially with the straight portion and the bent portion of the first active material portion 2221 located at the winding start end 22a and the bent portion of the first active material portion 2221 located at the winding end end 22b. The second clearance recess 3232 overlaps firstly with the bent portion of the first active material portion 2221 located at the winding end end 22b and does not overlap with the portion of the first active material portion 2221 located at the winding start end 22a.

[0194] Optionally, the distances between the first clearance recess 3231 and the second clearance recess 3232 along the first direction x are not equal.

[0195] In these alternative embodiments, the shape and size of the protrusion 322 are better adapted to the first active material portion 2221, and a tight fit is achieved between the electrode assembly 2 and the insulating component 32, reducing gaps or looseness caused by structural mismatch.

[0196] According to one embodiment of this application, such as Figure 13 and Figure 14As shown, in the first direction x, the size of the first clearance recess 3231 is greater than or equal to the size of the second clearance recess 3232, and the first direction x is perpendicular to the second direction y and the winding axis L.

[0197] In some examples, the plurality of clearance recesses 323 include a plurality of first clearance recesses 3231 and a plurality of second clearance recesses 3232, which are arranged alternately along the second direction y.

[0198] In some examples, the plurality of clearance recesses 323 include a plurality of first clearance recesses 3231 and a plurality of second clearance recesses 3232, wherein, in the second direction y, the second clearance recesses 3232 are provided on both sides of the first clearance recesses 3231.

[0199] In these alternative embodiments, in the first direction x, the size of the first clearance recess 3231 is greater than or equal to the size of the second clearance recess 3232, such that the first clearance recess 3231 has sufficient space to avoid the first active material portion 2221, further reducing interference to the electrode assembly 2.

[0200] According to one embodiment of this application, such as Figure 13 As shown, the second clearance recess 3232 is located on both sides of the first clearance recess 3231 along the second direction y.

[0201] For example, the plurality of clearance recesses 323 include a plurality of first clearance recesses 3231 and a plurality of second clearance recesses 3232. The plurality of first clearance recesses 3231 include a first clearance recess one and a first clearance recess two. The plurality of second clearance recesses 3232 include a second clearance recess one, a second clearance recess two, a second clearance recess three, and a second clearance recess four. The second clearance recess one, the second clearance recess two, the second clearance recess three, and the second clearance recess four are spaced apart along a second direction y. The first clearance recess one is located between the second clearance recess one and the second clearance recess two. The first clearance recess two is located between the second clearance recess three and the second clearance recess four.

[0202] In some examples, the first clearance recess 3231 overlaps with the first active material portion 2221 at the beginning of the winding 22a and the first active material portion 2221 at the end of the winding 22b of an electrode assembly 2, and the two second clearance recesses 3232 overlap with the first active material portion 2221 at the end of the winding 22b of an electrode assembly 2, and the first clearance recess 3231 is located between the two second clearance recesses 3232.

[0203] According to one embodiment of this application, such as Figure 3 and Figure 14As shown, the battery cell includes multiple electrode assemblies 2 stacked along the second direction y. The second clearance recess 3232 overlaps with the first active material portion 2221 located at the winding end 22b of the two adjacent electrode assemblies 2.

[0204] The battery cell includes multiple electrode assemblies 2 stacked along the second direction y. The first active material portion 2221 of each electrode assembly 2 located at the winding end 22b is disposed opposite to and adjacent to the first active material portion 2221 of the winding end 22b of the adjacent electrode assembly 2 along the second direction y. The second clearance recess 3232 overlaps with the first active material portion 2221 of the winding end 22b of both electrode assemblies 2.

[0205] In some examples, along the second direction y, the distance of the second clearance recess 3232 is greater than the distance of the first clearance recess 3231.

[0206] In these alternative embodiments, the first active material portion 2221 of two adjacent electrode assemblies 2 located at the winding end 22b overlaps with the same second clearance recess 3232, achieving a more compact internal space layout while satisfying reasonable clearance of the first active material portion 2221.

[0207] According to one embodiment of this application, the plurality of clearance recesses 323 include a plurality of first clearance recesses 3231 and a plurality of second clearance recesses 3232, and the plurality of first clearance recesses 3231 and the plurality of second clearance recesses 3232 are alternately arranged along a second direction y.

[0208] For example, a single battery cell includes a plurality of electrode assemblies 2 stacked along a second direction y. A plurality of clearance recesses 323 include a plurality of first clearance recesses 3231 and a plurality of second clearance recesses 3232. The first clearance recesses 3231 overlap with the first active material portions 2221 located at the winding beginning 22a and the winding end 22b of their corresponding electrode assemblies 2. The second clearance recesses 3232 overlap with the first active material portions 2221 located at the winding end 22b of two adjacent electrode assemblies 2. The plurality of first clearance recesses 3231 and the plurality of second clearance recesses 3232 are alternately arranged along the second direction y.

[0209] In these alternative embodiments, the first clearance recess 3231 and the second clearance recess 3232 are alternately arranged along the second direction y, so that the winding start end 22a and winding end end 22b of each electrode assembly 2 and the overall distribution of the multiple electrode assemblies 2 are more uniform in the direction of electrode assembly 2 stacking.

[0210] According to one embodiment of this application, such as Figure 11 and Figure 12As shown, in the first direction x, the projection of the avoidance recess 323 covers the first active material portion 2221, and the avoidance recess 323 is at least partially arc-shaped.

[0211] In some examples, the battery cell includes an electrode assembly 2, in the first direction x, the projection of the avoidance recess 323 covers the first active material portion 2221 located at the winding start end 22a and the first active material portion 2221 located at the winding end end 22b, and the avoidance recess 323 is arc-shaped.

[0212] In other examples, the battery cell includes multiple electrode assemblies 2 stacked along the second direction y, and in the first direction x, the projection of the avoidance recess 323 covers the first active material portion 2221 of each electrode assembly 2 located at the winding start end 22a and the winding end end 22b, and the avoidance recess 323 is arc-shaped.

[0213] In these alternative embodiments, the avoidance recess 323 is at least partially arc-shaped, which can avoid the first active material portion 2221 to a greater extent, further reducing the compression on the counter electrode assembly 2.

[0214] According to one embodiment of this application, the electrode assembly 2 includes a flat region 2a and a bent region 2b connected to both ends of the flat region 2a. The protrusion 322 overlaps with both the flat region 2a and the bent region, and a portion of the avoidance recess 323 overlaps with the first active material portion 2221 provided in the flat region 2a.

[0215] In some examples, the positive electrode 21 and the negative electrode 22 are wound along the winding direction M to form a straight region 2a and a bent region 2b connecting the two ends of the straight region 2a. The protrusion 322 overlaps with both the straight region 2a and the bent region, and the recess 323 avoids overlap with the first active material portion 2221 provided in the straight region 2a.

[0216] In other examples, the positive electrode 21 and the negative electrode 22 are wound along the winding direction M to form a straight region 2a and a bent region 2b connecting the two ends of the straight region 2a. The protrusion 322 overlaps with both the straight region 2a and the bent region. A portion of the avoidance recess 323 overlaps with the first active material portion 2221 provided in the straight region 2a, and another portion of the avoidance recess 323 overlaps with the first active material portion 2221 in the bent region 2b.

[0217] According to one embodiment of this application, the first active material portion 2221 is wound 1 to 10 turns along the winding direction M.

[0218] For example, the first active material portion 2221 located at the winding head end 22a is wound 1 to 10 times along the winding direction M.

[0219] Optionally, the first active material portion 2221 located at the winding head end 22a is wound 1 to 3 times along the winding direction M.

[0220] For example, the first active material portion 2221 located at the winding end 22b is wound 1 to 5 times along the winding direction M.

[0221] Optionally, the first active material portion 2221 located at the winding end 22b is wound 1 to 2 turns along the winding direction M.

[0222] In these alternative embodiments, this arrangement is advantageous in increasing the arrangement area of ​​the first active material portion 2221, while reducing the space occupied by the negative electrode plate 22, reducing the overall volume and weight of the battery cell, increasing energy density, and improving the reliability of the battery cell.

[0223] Secondly, this application provides a battery device including the aforementioned battery cell.

[0224] According to one embodiment of this application, the insulating component 32 is located on the underside of the electrode assembly 2.

[0225] In these alternative embodiments, the insulating component 32 is located below the electrode assembly 2. This can be understood as the battery cell being inverted so that the insulating component 32 is located below the electrode assembly 2, and the insulating component 32 is used to support part of the electrode assembly 2.

[0226] Thirdly, this application provides an electrical device, including a battery cell or a battery device as described above, wherein the battery cell or battery device is used to store or provide electrical energy.

[0227] According to some embodiments of this application, see Figures 3 to 7 , Figure 14 This application provides a battery cell, which includes a housing 1, an electrode assembly 2, and an end cap assembly 3. The housing 1 has an opening 11.

[0228] Electrode assembly 2 is disposed within housing 1. Electrode assembly 2 includes a positive electrode 21 and a negative electrode 22. The positive electrode 21 and the negative electrode 22 are wound along the winding direction M. The negative electrode 22 has a winding start end 22a and a winding end end 22b disposed opposite to each other along the winding direction M. The negative electrode 22 includes a negative current collector 221 and a negative active material layer 222 disposed on the surface of the negative current collector 221. The negative active material layer 222 includes two first active material portions 2221 and a second active material portion 2222. The first active material portions 2221 are disposed at both ends of the second active material portions 2222 along the winding direction M, and the first active material portions 2221 extend along the winding direction M to the winding start end 22a or the winding end end 22b. In the winding axis L, the size of the first active material portion 2221 is larger than the size of the second active material portion 2222.

[0229] The end cap assembly 3 includes an end cap 31 and an insulating component 32. The end cap 31 closes the opening 11. The end cap 31 and the electrode assembly 2 are arranged along the winding axis L. The insulating component 32 is disposed on the side of the end cap 31 facing the electrode assembly 2. The insulating component 32 includes a main body 321 and two protrusions 322. The main body 321 is connected to the end cap 31. The protrusions 322 protrude from the side of the main body 321 facing away from the end cap 31. The two protrusions 322 are disposed at both ends of the main body 321 along the first direction x. The protrusions 322 include a first... A first wall 3221 and a second wall 3222 connected to the first wall 3221. The first wall 3221 is disposed on the side of the protrusion 322 away from the end cap 31 along the winding axis L. The second wall 3222 is disposed on the side of the protrusion 322 close to the first active material portion 2221 along the first direction x. The first wall 3221 is provided with a relief recess 323 and the relief recess 323 extends to the second wall 3222. In the winding axis L, the first active material portion 2221 and the relief recess 323 at least partially overlap. There are multiple clearance recesses 323, which are spaced apart along the second direction y. Each clearance recess 323 includes a first clearance recess 3231 and a second clearance recess 3232. The first clearance recess 3231 overlaps with both the first active material portion 2221 located at the beginning of the winding 22a and the first active material portion 2221 located at the end of the winding 22b. The second clearance recess 3232 overlaps only with the first active material portion 2221 located at the end of the winding 22b. In the first direction x, the size of the first clearance recess 3231 is greater than or equal to the size of the second clearance recess 3232. The first direction x is perpendicular to the second direction y and the winding axis L. The second clearance recesses 3232 are located on both sides of the first clearance recess 3231 along the second direction y.

[0230] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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 in that, include: The shell has an opening; An electrode assembly is disposed within the housing. The electrode assembly includes a positive electrode and a negative electrode, which are wound along a winding direction. The negative electrode has a winding start end and a winding end end disposed opposite to each other along the winding direction. The negative electrode includes a negative current collector and a negative active material layer disposed on the surface of the negative current collector. The negative active material layer includes a first active material portion and a second active material portion. The first active material portion is disposed at at least one end of the second active material portion along the winding direction, and the first active material portion extends along the winding direction to the winding start end or the winding end end. In the winding axial direction, the size of the first active material portion is larger than the size of the second active material portion. An end cap assembly includes an end cap and an insulating component. The end cap covers the opening. The end cap and the electrode assembly are disposed along the winding axis. The insulating component is disposed on the side of the end cap facing the electrode assembly. The insulating component includes a body and a protrusion. The body is connected to the end cap. The protrusion protrudes from the side of the body facing away from the end cap. The protrusion has a clearance recess. Along the winding axis, the first active material portion at least partially overlaps with the clearance recess.

2. The battery cell according to claim 1, characterized in that, The end cap assembly includes two protrusions disposed at both ends of the body along a first direction, and each protrusion has at least one clearance recess, wherein the first direction is perpendicular to the winding axis.

3. The battery cell according to claim 1, characterized in that, The clearance recess extends along a first direction to the edge of the protrusion, the first direction being perpendicular to the winding axis.

4. The battery cell according to claim 1, characterized in that, The protrusion includes a first wall and a second wall connected to the first wall. The first wall is disposed on the side of the protrusion away from the end cap along the winding axis. The second wall is disposed on the side of the protrusion close to the first active material portion along a first direction. The first wall has the avoidance recess and the avoidance recess extends to the second wall. The first direction is perpendicular to the winding axis.

5. The battery cell according to claim 4, characterized in that, The second wall has a hole that extends through the second wall along the first direction, and the hole is spaced apart from the relief recess.

6. The battery cell according to claim 1, characterized in that, The protrusion includes a plurality of clearance recesses, which are spaced apart along a second direction perpendicular to the winding axis.

7. The battery cell according to claim 6, characterized in that, The negative electrode active material layer includes two first active material portions, one of which extends along the winding direction to the winding start end, and the other of which extends along the winding direction to the winding end. The plurality of clearance recesses include a first clearance recess and a second clearance recess, wherein the first clearance recess overlaps with both the first active material portion located at the beginning of the winding and the first active material portion located at the end of the winding, and the second clearance recess overlaps with only the first active material portion located at the end of the winding.

8. The battery cell according to claim 7, characterized in that, In a first direction, the size of the first clearance recess is greater than or equal to the size of the second clearance recess, and the first direction is perpendicular to the second direction and the winding axis.

9. The battery cell according to claim 8, characterized in that, The second clearance recess is located on both sides of the first clearance recess along the second direction.

10. The battery cell according to claim 7, characterized in that, The battery cell includes a plurality of electrode assemblies stacked along the second direction. The second clearance recess overlaps with the first active material portion of the two adjacent electrode assemblies located at the winding end.

11. The battery cell according to claim 10, characterized in that, The plurality of clearance recesses include a plurality of first clearance recesses and a plurality of second clearance recesses, which are alternately arranged along the second direction.

12. The battery cell according to claim 1, characterized in that, In a first direction, the projection of the avoidance recess covers the first active material portion, the avoidance recess being at least partially arc-shaped, and the first direction is perpendicular to the winding axis.

13. The battery cell according to claim 1, characterized in that, The electrode assembly includes a flat region and a bent region connecting both ends of the flat region. The protrusion overlaps with both the flat region and the bent region. A portion of the avoidance recess overlaps with the first active material portion provided in the flat region.

14. The battery cell according to claim 1, characterized in that, The first active material portion is wound 1 to 10 times along the winding direction.

15. A battery device, characterized in that, It includes multiple battery cells according to any one of claims 1 to 14.

16. The battery device according to claim 15, characterized in that, The insulating component is located on the underside of the electrode assembly.

17. An electrical device, characterized in that, Includes a battery cell according to any one of claims 1 to 14 or a battery device according to claim 15 or 16, wherein the battery cell or the battery device is used to store or provide electrical energy.

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