Battery monomer, battery and electric equipment

Abstract

The embodiment of the invention provides a battery monomer, a battery and electric equipment. The battery cell includes a housing and an electrode assembly. The electrode assembly is arranged in the shell and comprises a positive pole piece, a negative pole piece and an isolating membrane, and the isolating membrane is arranged between the positive pole piece and the negative pole piece; wherein in the thickness direction of the negative pole piece, the negative pole piece is provided with a first surface facing the isolating membrane, and the first surface is provided with a first convex part. According to the technical scheme of the embodiment of the invention, the reliability of the battery monomer can be improved.

Description

Technical Field

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

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

[0003] Battery reliability is a crucial factor in battery manufacturing. Therefore, improving battery reliability is a pressing technical challenge in battery technology. Summary of the Invention

[0004] This application provides a battery cell, a battery, and an electrical device that can improve the reliability of the battery cell.

[0005] This application is achieved through the following technical solution:

[0006] In a first aspect, embodiments of this application provide a battery cell, which includes a housing and an electrode assembly. The electrode assembly is disposed within the housing and includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the positive and negative electrode; wherein, in the thickness direction of the negative electrode, the negative electrode has a first surface facing the separator, and the first surface is provided with a first protrusion.

[0007] According to the embodiments of this application, the battery cell has a first protrusion on its first surface facing the separator. The first protrusion protrudes from the first surface, which can increase the distance between the first surface and the separator, reserve space for dendrite growth, slow down the speed at which dendrites pierce the separator, reduce the risk of dendrites penetrating the separator and causing a short circuit between the positive and negative electrodes, thereby improving the reliability of the battery cell.

[0008] According to some embodiments of this application, a first insulating layer is provided at the end of the first protrusion away from the first surface.

[0009] In the above scheme, the provision of the first insulating layer can reduce the risk of dendrites growing at the end of the first protrusion away from the first surface and puncturing the separator, thereby further improving the reliability of the battery cell.

[0010] According to some embodiments of this application, the first protrusion includes a first end face and a first outer peripheral face, the first outer peripheral face surrounds the first end face, and the first outer peripheral face connects the first end face and the first surface; the first insulating layer covers the first end face and part of the first outer peripheral face.

[0011] In the above scheme, the first insulating layer covers the first end face and part of the first outer peripheral face, further reducing the risk of dendrite formation on the first protrusion, thereby improving the reliability of the battery cell.

[0012] According to some embodiments of this application, the first insulating layer is a coating or adhesive tape.

[0013] In the above scheme, the coating can be formed by the condensation of an insulating slurry coating, which is relatively easy to process; the adhesive tape structure is simple and easy to assemble with the first protrusion.

[0014] According to some embodiments of this application, the material of the first insulating layer includes polyvinylidene fluoride or an alumina-polyvinylidene fluoride mixture.

[0015] In the above schemes, polyvinylidene fluoride or alumina-polyvinylidene fluoride mixtures have better insulation performance.

[0016] According to some embodiments of this application, along the thickness direction of the negative electrode sheet, the diameter of the projection of the first protrusion is greater than or equal to 0.1 mm and less than or equal to 5 mm.

[0017] In the above scheme, the diameter of the projection of the first protrusion meets the above range. On the one hand, when the diameter of the projection of the first protrusion is greater than or equal to 0.1 mm, it is easy to process and manufacture. On the other hand, when the diameter of the projection of the first protrusion is less than or equal to 5 mm, the first protrusion occupies a smaller area so that the first surface has a larger adhesion area for metal ions, reducing the risk of dendrites piercing the isolation film.

[0018] According to some embodiments of this application, there are multiple first protrusions, and the multiple first protrusions are arranged in a rectangular array or a rhomboid array.

[0019] In the above scheme, the multiple first protrusions are arranged in a rectangular or rhomboid array, which facilitates processing and manufacturing, facilitates the formation of multiple support positions between the first surface and the separator, and increases the distance between the first surface and the separator.

[0020] According to some embodiments of this application, the first protrusion is cylindrical, frustum-shaped, or hemispherical.

[0021] In the above scheme, the first protrusion is cylindrical, frustum-shaped, or hemispherical, which facilitates processing and manufacturing.

[0022] According to some embodiments of this application, the negative electrode sheet also has a second surface, the second surface and the first surface are disposed opposite to each other along the thickness direction, the second surface is provided with a first recess that is recessed into the first surface, and the position of the first recess corresponds to the position of the first protrusion.

[0023] In the above scheme, the position of the first concave part corresponds to the position of the first convex part. The first convex part can be formed by stamping, which makes the processing and manufacturing difficulty relatively low. At the same time, the first concave part can increase the surface area of ​​the negative electrode sheet and provide space for dendrite growth, which can reduce the risk of dendrites piercing the separator on both sides of the thickness direction of the negative electrode sheet.

[0024] According to some embodiments of this application, the second surface is provided with a second protrusion, and the first surface is provided with a second recess that is recessed into the second surface, the position of the second recess corresponding to the position of the second protrusion.

[0025] In the above scheme, the setting of the second protrusion can increase the distance between the second surface and the corresponding separator, reserve space for dendrite growth, reduce the risk of dendrites penetrating the separator, and further improve the reliability of the battery cell; at the same time, the second concave portion can increase the surface area of ​​the negative electrode sheet, and the second concave portion can provide space for dendrite growth, which can reduce the risk of dendrites piercing the separator on both sides of the thickness direction of the negative electrode sheet.

[0026] According to some embodiments of this application, a second insulating layer is provided at the end of the second protrusion away from the second surface.

[0027] In the above scheme, the provision of the second insulating layer can reduce the risk of dendrites growing at the end of the second protrusion away from the second surface and puncturing the separator, thereby further improving the reliability of the battery cell.

[0028] According to some embodiments of this application, there are multiple second protrusions, and the multiple second protrusions are arranged in a rectangular array or a rhomboid array.

[0029] In the above scheme, multiple second protrusions are arranged in a rectangular or rhomboid array to form multiple support positions between the second surface and the separator, thereby increasing the distance between the second surface and the separator.

[0030] According to some embodiments of this application, a first surface is provided with a plurality of first protrusion groups and a plurality of second recess groups arranged alternately along a first direction. Each first protrusion group includes a plurality of first protrusions arranged at intervals along a second direction, and each second recess group includes a plurality of second recesses arranged at intervals along a second direction. The first direction, the second direction, and the thickness direction are perpendicular to each other.

[0031] In the above scheme, multiple first convex groups and multiple second concave groups are alternately arranged on the first surface along the first direction, that is, multiple first convex groups and multiple second concave groups are alternately arranged in the first direction, so as to reserve dendrite growth space on both sides of the thickness direction of the negative electrode sheet and reduce the risk of dendrites piercing the separator.

[0032] According to some embodiments of this application, the first convex portion and the second concave portion are aligned along the second direction.

[0033] In the above scheme, the first convex part and the second concave part are aligned, which facilitates processing and manufacturing.

[0034] According to some embodiments of this application, on a first surface, a plurality of first protrusions and a plurality of second recesses are alternately arranged along a first direction, and the plurality of first protrusions and a plurality of second recesses are alternately arranged along a second direction.

[0035] In the above scheme, the first convex part and the second concave part are staggered, which makes it easier to provide more dendrite growth space on both sides of the thickness direction of the negative electrode sheet, and reduce the risk of dendrites piercing the separator.

[0036] According to some embodiments of this application, a through-hole group is provided between each first protrusion group and an adjacent second concave group, and each through-hole group includes a plurality of through holes arranged at intervals along a second direction, the through holes penetrating the negative electrode sheet along the thickness direction of the negative electrode sheet.

[0037] In the above scheme, in the first direction, a through hole group is provided between each first protrusion group and an adjacent second concave group to increase the dendrite growth space and reduce the risk of dendrites piercing the isolation membrane.

[0038] According to some embodiments of this application, along the second direction, the through hole and the first protrusion are offset from each other, and the through hole and the second recess are offset from each other; along the first direction, the through hole and the first protrusion are offset from each other, and the through hole and the second recess are offset from each other.

[0039] In the above scheme, the first protrusion and the second concave part are respectively staggered from the through hole, which makes the processing and manufacturing process easier and more convenient.

[0040] According to some embodiments of this application, the negative electrode sheet is provided with a through hole, which extends through the negative electrode sheet along the thickness direction.

[0041] In the above scheme, the negative electrode sheet is provided with through holes. The through holes can provide space for dendrite growth, slow down the speed at which dendrites pierce the separator, and reduce the risk of short circuit between the positive and negative electrodes caused by dendrites penetrating the separator.

[0042] According to some embodiments of this application, there are multiple through holes, which are arranged in a rectangular or diamond array.

[0043] In the above scheme, multiple through holes are arranged in a rectangular or rhomboid array, which facilitates processing and manufacturing, and can provide more space for dendrite growth, reducing the risk of dendrites piercing the isolation membrane.

[0044] According to some embodiments of this application, the number of through holes is multiple, and the ratio of the total area of ​​all through holes to the area of ​​the first surface is greater than or equal to 3% and less than or equal to 25%.

[0045] In the above scheme, the ratio of the total area of ​​the through holes to the area of ​​the first surface satisfies the above relationship. On the one hand, when the ratio of the total area of ​​the through holes to the area of ​​the first surface is greater than or equal to 3%, it can increase the dendrite growth space. On the other hand, when the ratio of the total area of ​​the through holes to the area of ​​the first surface is less than or equal to 25%, it occupies a smaller area and has a smaller impact on energy density.

[0046] According to some embodiments of this application, the battery cell is a metal battery cell.

[0047] Secondly, embodiments of this application also provide a battery comprising a battery cell as provided in any of the above embodiments.

[0048] Thirdly, embodiments of this application also provide an electrical device, which includes a battery cell or battery as provided in any of the above embodiments, the battery cell or battery being used to provide electrical energy.

[0049] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0052] Figure 2 This is an exploded view of the battery structure provided in some embodiments of this application;

[0053] Figure 3 This is an exploded view of the structure of a battery cell provided in some embodiments of this application;

[0054] Figure 4 This is a partial structural schematic diagram of an electrode assembly provided in some embodiments of this application;

[0055] Figure 5 This is a schematic diagram of the assembly of the first insulating layer and the first protrusion provided in some embodiments of this application;

[0056] Figure 6 This is a partial structural schematic diagram of an electrode assembly provided in other embodiments of this application;

[0057] Figure 7 This is a partial structural cross-sectional view of the negative electrode sheet provided in some embodiments of this application;

[0058] Figure 8 This is a partial structural schematic diagram of the negative electrode sheet provided in some embodiments of this application;

[0059] Figure 9 This is a schematic diagram of the through hole structure of the negative electrode sheet provided in some embodiments of this application.

[0060] Icons: 100-Battery; 10-Casing; 11-First Sub-Casing; 12-Second Sub-Casing; 20-Battery Cell; 21-Outer Shell; 211-Housing Shell; 2111-First Wall; 2112-Second Wall; 2113-Third Wall; 212-End Cap; 212a-Electrode Terminal; 22-Electrode Assembly; 22a-Taper; 23-Positive Electrode; 24-Negative Electrode; 24a-First Surface; 24b-Second Surface; 240-Negative Current Collector; 241-First Protrusion; 2410-First Protrusion Group; 2411-First End Face; 2412-First Outer Peripheral Surface; 242-Through Hole; 2 420 - Through-hole group; 243 - First recess; 244 - Second protrusion; 2441 - Second end face; 2442 - Second outer peripheral surface; 245 - Second recess; 2450 - Second recess group; 246 - First insulating layer; 247 - Second insulating layer; 25 - Separator; 25a - First separator; 25b - Second separator; 26 - Adapter; 200 - Controller; 300 - Motor; 1000 - Vehicle; X - Length direction of battery cell; Y - Width direction of battery cell; Z - Height direction of battery cell; X1 - First direction; Y1 - Second direction; Z1 - Thickness direction of negative electrode sheet. Detailed Implementation

[0061] 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 and completely 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.

[0062] 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.

[0063] In this application, the reference to "embodiment" means that a specific 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 mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0064] 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.

[0065] 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, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0066] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0067] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0068] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0069] 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.

[0070] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0071] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0072] The battery cells can be, but are not limited to, lithium metal batteries, sodium metal batteries, etc.

[0073] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0074] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0075] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0076] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be made of stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium with a silver-plated surface. 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 alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0077] As an example, the positive electrode active material 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 positive electrode active materials for batteries may also be used.

[0078] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0079] As an example, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, or made of carbon, nickel, or titanium, etc.

[0080] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0081] 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 ceramic. 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, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0082] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0083] In some implementations, the electrode assembly is a stacked structure.

[0084] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0085] In some embodiments, the housing includes an end cap and a casing, the casing having an opening, and the end cap closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The casing may have one or more openings. The end cap may also be provided one or more times.

[0086] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal can be located on the end cap or on the housing.

[0087] In some implementations, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cells.

[0088] As an example, a battery cell can be a cylindrical battery cell, 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 batteries, such as hexagonal prismatic batteries.

[0089] The development of battery technology must take into account multiple design factors, such as energy density, discharge capacity, charge-discharge rate and other performance parameters. In addition, battery reliability also needs to be considered.

[0090] In some embodiments, the negative electrode of a metal battery cell includes a negative current collector, and the negative electrode does not contain a negative active material.

[0091] In some embodiments, dendrites inevitably form during the deposition of negative electrode metal in a metal battery cell. If the dendrites grow too long, they will penetrate the separator and cause a short circuit between the positive and negative electrodes, thereby causing battery safety issues and resulting in low reliability of the metal battery cell.

[0092] In view of this, in order to solve the problem of low reliability of metal battery cells caused by dendrites piercing the separator, this application provides a battery cell including a casing and an electrode assembly, the electrode assembly being disposed within the casing. The electrode assembly includes a positive electrode, a negative electrode, and a separator, the separator being disposed between the positive and negative electrode; wherein, in the thickness direction of the negative electrode, the negative electrode has a first surface facing the separator, the first surface having a first protrusion. This battery cell can reserve space for dendrite growth, improving the reliability of the battery cell.

[0093] In such a battery cell, a first protrusion is provided on the first surface. The first protrusion protrudes from the first surface, which can increase the distance between the first surface and the opposite separator, reserve space for dendrite growth, slow down the speed at which dendrites pierce the separator, reduce the risk of dendrites penetrating the separator and causing a short circuit between the positive and negative electrodes, thereby improving the reliability of the battery cell.

[0094] The batteries disclosed in this application can be used, but are not limited to, in electrical equipment such as vehicles, ships, or aircraft. A power system for such electrical equipment can be constructed using batteries disclosed in this application.

[0095] 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 bicycles, electric motorcycles, 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.

[0096] 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.

[0097] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. 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. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000's electrical system, such as meeting the power requirements for starting, navigation, and operation of the vehicle 1000.

[0098] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0099] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0100] Please refer to Figure 2 , Figure 2 This is an exploded view of the battery structure provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first sub-housing 11 and a second sub-housing 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second sub-housing 12 may be a hollow structure with one open end, while the first sub-housing 11 may be a plate-like structure, covering the open side of the second sub-housing 12 so that the first sub-housing 11 and the second sub-housing 12 jointly define the space. Alternatively, both the first sub-housing 11 and the second sub-housing 12 may be hollow structures with one open side, with the open side of the first sub-housing 11 covering the open side of the second sub-housing 12.

[0101] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0102] Among them, the battery cell 20 can be a secondary battery or a primary battery; the battery cell 20 can also be a lithium metal battery cell, a sodium metal battery cell or other metal battery cell.

[0103] Please refer to Figure 3 , Figure 3 This is an exploded view of the structure of a battery cell provided in some embodiments of this application. For example... Figure 3 As shown, the battery cell 20 includes a housing 21, an electrode assembly 22, and other functional components. The housing 21 includes a casing 211 and an end cap 212. The casing 211 has an opening, and the end cap 212 closes the opening to isolate the internal environment of the battery cell 20 from the external environment.

[0104] The housing 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the end cap 212 can be independent components. The housing 211 can have various shapes and sizes. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The housing 211 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0105] End cap 212 refers to a component that covers the opening of housing 211 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 212 can be adapted to the shape of housing 211 to fit it. Optionally, end cap 212 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 212 is not easily deformed under pressure and impact, giving battery cell 20 higher structural strength and improved reliability. Functional components such as electrode terminals 212a can be provided on end cap 212. Electrode terminals 212a can be electrically connected to the tabs 22a of electrode assembly 22 via adapter 26 for outputting or inputting electrical energy to battery cell 20. The material of end cap 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating structure may be provided on the inner side of the end cap 212. The insulating structure can be used to isolate the electrical connection components within the housing 211 from the end cap 212 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0106] Electrode assembly 22 is the component in the battery cell 20 where the electrochemical reaction takes place. The housing 211 may contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or stacking positive and negative electrode plates, and usually a separator is provided between the positive and negative electrode plates to separate the positive and negative electrode plates and prevent internal short circuits between them.

[0107] Please refer to Figure 3 and further refer to Figure 4 , Figure 4 This is a partial structural schematic diagram of an electrode assembly provided in some embodiments of this application. Embodiments of this application provide a battery cell 20, which includes a housing 21 and an electrode assembly 22. The electrode assembly 22 is disposed within the housing 21 and includes a positive electrode 23, a negative electrode 24, and a separator 25, with the separator 25 disposed between the positive electrode 23 and the negative electrode 24. Specifically, in the thickness direction Z1 of the negative electrode 24, the negative electrode 24 has a first surface 24a facing the separator 25, and the first surface 24a has a first protrusion 241.

[0108] The battery cell 20 can be a prismatic battery cell, a cylindrical battery cell, or a pouch battery cell.

[0109] The housing 21 is used to provide a cavity for accommodating the electrode assembly 22, and the cavity may also contain an electrolyte.

[0110] In some embodiments, please refer to Figure 3The outer casing 21 may be cuboid in shape. The outer casing 21 may include a housing 211 and an end cap 212. The housing 211 has an opening, and the end cap 212 closes the opening. The housing 211 may include two first walls 2111 arranged opposite each other along the length direction X of the battery cell, two second walls 2112 arranged opposite each other along the width direction Y of the battery cell, and a third wall 2113. The third wall 2113 and the end cap 212 are arranged opposite each other along the height direction Z of the battery cell. The length direction X of the battery cell, the width direction Y of the battery cell, and the height direction Z of the battery cell are perpendicular to each other.

[0111] The electrode assembly 22 is disposed within the receiving cavity of the housing 21.

[0112] In some embodiments, the electrode assembly 22 may be a stacked structure or a wound structure.

[0113] The negative electrode 24 includes a negative electrode current collector 240. The surface of the negative electrode current collector 240 is not provided with a negative electrode active material, and the first surface 24a can be the surface of the negative electrode current collector 240. The negative electrode current collector 240 can be a metal foil or a composite current collector; for example, a metal layer can be provided on the surface of a substrate. The material of the negative electrode current collector 240 can be copper, aluminum, steel, etc.

[0114] In some embodiments, the first surface 24a is a surface of the negative electrode 24 in its thickness direction, and the first surface 24a is perpendicular to the thickness direction Z1 of the negative electrode. The first protrusion 241 protrudes from the first surface 24a, which can increase the distance between the first surface 24a and the opposing separator 25.

[0115] The first surface 24a is provided with a first protrusion 241, which protrudes from the first surface 24a and increases the distance between the first surface 24a and the opposite separator 25, reserving space for dendrite growth, slowing down the speed at which dendrites pierce the separator 25, reducing the risk of short circuit between positive and negative electrodes caused by dendrites penetrating the separator 25, thereby improving the reliability of the battery cell 20.

[0116] Please refer to Figure 5 , Figure 5 This is a schematic diagram illustrating the assembly of the first insulating layer and the first protrusion according to some embodiments of this application. According to some embodiments of this application, the first insulating layer 246 is provided at the end of the first protrusion 241 away from the first surface 24a.

[0117] The first protrusion 241 protrudes from the first surface 24a. The first protrusion 241 has a first end and a second end. The first end and the second end are arranged opposite to each other in a direction perpendicular to the first surface 24a. The first end is connected to the first protrusion 241, and the second end is close to the isolation membrane 25 opposite to the first surface 24a.

[0118] Because the second end is close to the separator 25, the first insulating layer 246 can prevent dendrite growth, thereby reducing the risk of dendrites growing too fast and puncturing the separator 25, and further improving the reliability of the battery cell 20.

[0119] Please refer to Figure 5 According to some embodiments of this application, the first protrusion 241 includes a first end face 2411 and a first outer peripheral face 2412. The first outer peripheral face 2412 surrounds the first end face 2411 and connects the first end face 2411 and the first surface 24a. The first insulating layer 246 covers the first end face 2411 and part of the first outer peripheral face 2412.

[0120] The first end face 2411 is the end face of the first protrusion 241 that is away from the first surface 24a, and the first outer peripheral surface 2412 is disposed around the edge of the first end face 2411. For example, when the first protrusion 241 has a columnar structure, the first end face 2411 is closer to the separator 25 than the first outer peripheral surface 2412.

[0121] The first insulating layer 246 covers the first end face 2411 and a portion of the first outer peripheral face 2412, such that the portion of the first protrusion 241 near the separator 25 is covered by the first insulating layer 246, which can reduce the risk of dendrites growing too fast and puncturing the separator 25.

[0122] In the above scheme, the first insulating layer 246 covers the first end face 2411 and part of the first outer peripheral face 2412, further reducing the risk of dendrites forming on the first protrusion 241, thereby improving the reliability of the battery cell 20.

[0123] According to some embodiments of this application, the first insulating layer 246 is a coating or adhesive tape.

[0124] In some embodiments, the first insulating layer 246 is a coating formed by the solidification of an insulating slurry layer. The insulating slurry is applied to the first protrusion 241 by a coating process, which is relatively easy to process.

[0125] In some embodiments, the first insulating layer 246 is adhesive tape, which has a simple structure and is easy to assemble with the first protrusion 241.

[0126] According to some embodiments of this application, the material of the first insulating layer 246 includes polyvinylidene fluoride or an alumina-polyvinylidene fluoride mixture.

[0127] Polyvinylidene fluoride can be applied as an insulating paste to the first protrusion 241 to form a first insulating layer 246.

[0128] The alumina-polyvinylidene fluoride mixture can be applied as an insulating paste to the first protrusion 241 to form the first insulating layer 246.

[0129] In the above schemes, polyvinylidene fluoride or alumina-polyvinylidene fluoride mixtures have better insulation performance.

[0130] According to some embodiments of this application, along the thickness direction Z1 of the negative electrode sheet, the diameter of the projection of the first protrusion 241 is greater than or equal to 0.1 mm and less than or equal to 5 mm.

[0131] When the electrode assembly 22 is a wound structure, the projection of the first protrusion 241 refers to the projection of the first protrusion 241 along the thickness direction Z1 of the negative electrode sheet after the negative electrode sheet 24 is unfolded.

[0132] The diameter of the projection of the first protrusion 241 refers to the diameter of the circumcircle of the projection of the first protrusion 241. For example, if the projection of the first protrusion 241 is a circle, the diameter of the projection of the first protrusion 241 is the outer diameter of the projection of the first protrusion 241.

[0133] Optionally, the diameter of the projection of the first protrusion 241 is greater than or equal to 1 mm and less than or equal to 3 mm.

[0134] Optionally, the diameter of the projection of the first protrusion 241 can be any one of 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm or any range between any two.

[0135] In the above scheme, the diameter of the projection of the first protrusion 241 meets the above range. On the one hand, when the diameter of the projection of the first protrusion 241 is greater than or equal to 0.1 mm, it is easy to process and manufacture. On the other hand, when the diameter of the projection of the first protrusion 241 is less than or equal to 5 mm, the first protrusion 241 occupies a smaller area so that the first surface 24a has a larger adhesion area for metal ions, reducing the risk of dendrites piercing the isolation film 25.

[0136] According to some embodiments of this application, there are multiple first protrusions 241, and the multiple first protrusions 241 are arranged in a rectangular array or a rhomboid array.

[0137] Multiple first protrusions 241 are arranged in a rectangular array, which can be distributed at intervals along the length and width directions of the negative electrode plate 24, facilitating the layout of multiple first protrusions 241.

[0138] Multiple first protrusions 241 are arranged in a rhomboid array. For example, the two diagonals of the rhombus can be parallel to the length and width directions of the negative electrode plate 24, respectively, which facilitates the layout of multiple first protrusions 241.

[0139] In the above scheme, the multiple first protrusions 241 are arranged in a rectangular or rhomboid array, which is convenient for processing and manufacturing, and facilitates the formation of multiple support positions between the first surface 24a and the isolation membrane 25, thereby increasing the distance between the first surface 24a and the isolation membrane 25.

[0140] According to some embodiments of this application, the first protrusion 241 is cylindrical, frustum-shaped, or hemispherical.

[0141] When the first protrusion 241 is cylindrical, the connection between the cylindrical end face and the outer peripheral surface is rounded, reducing the damage of the first protrusion 241 to the separator 25.

[0142] When the first protrusion 241 is frustoconical, the connection between the top surface and the side surface of the first protrusion 241 is rounded.

[0143] In some embodiments, the first protrusion 241 may also be prismatic.

[0144] In some embodiments, the first protrusion 241 may also be a combination structure of a cylinder and a hemisphere.

[0145] In the above scheme, the first protrusion 241 is cylindrical, frustum-shaped, or hemispherical, which is convenient for processing and manufacturing.

[0146] Please refer to Figure 6 and Figure 7 , Figure 6 This is a partial structural schematic diagram of an electrode assembly provided in other embodiments of this application. Figure 7 This is a partial structural cross-sectional view of a negative electrode sheet provided in some embodiments of this application. According to some embodiments of this application, the negative electrode sheet 24 further has a second surface 24b, the second surface 24b and the first surface 24a are disposed opposite to each other along the thickness direction, the second surface 24b is provided with a first recess 243 recessed into the first surface 24a, and the position of the first recess 243 corresponds to the position of the first protrusion 241.

[0147] The second surface 24b and the first surface 24a are two surfaces of the negative electrode 24 that are opposite each other in the thickness direction. The first surface 24a and the second surface 24b can be two surfaces of the negative electrode current collector 240 that are opposite each other in the thickness direction Z1 of the negative electrode.

[0148] The position of the first concave portion 243 corresponds to the position of the first convex portion 241. The first convex portion 241 and the second concave portion form a hollow structure. The negative electrode sheet 24 can be formed by stamping to form the first convex portion 241 and the first concave portion 243.

[0149] In the above scheme, the position of the first concave portion 243 corresponds to the position of the first convex portion 241. The first convex portion 241 can be formed by stamping, which is relatively easy to manufacture. At the same time, the first concave portion 243 can increase the surface area of ​​the negative electrode sheet 24. The first concave portion 243 can provide dendrite growth space, which can reduce the risk of dendrites piercing the separator 25 on both sides of the thickness direction Z1 of the negative electrode sheet.

[0150] Please refer to Figure 7 According to some embodiments of this application, the second surface 24b is provided with a second protrusion 244, and the first surface 24a is provided with a second recess 245 that is recessed into the second surface 24b. The position of the second recess 245 corresponds to the position of the second protrusion 244.

[0151] The second protrusion 244 and the first protrusion 241 are located on opposite sides of the thickness direction Z1 of the negative electrode sheet. On opposite sides of the thickness direction Z1 of the negative electrode sheet, the first protrusion 241 and the second protrusion 244 correspond to two separator films 25. For example, the separator film 25 includes a first separator film 25a and a second separator film 25b. The first separator film 25a is disposed corresponding to the first surface 24a, and the second separator film 25b is disposed corresponding to the second surface 24b. The first protrusion 241 is disposed towards the first separator film 25a, and the second protrusion 244 is disposed towards the second separator film 25b. The first protrusion 241 increases the distance between the first surface 24a and the first separator film 25a, and the second protrusion 244 increases the distance between the second surface 24b and the second separator film 25b.

[0152] The position of the second concave portion 245 corresponds to the position of the second convex portion 244. The second convex portion 244 and the second concave portion 245 form a hollow structure. The negative electrode sheet 24 can be formed by stamping to form the second convex portion 244 and the second concave portion 245.

[0153] In the above scheme, the provision of the second protrusion 244 can increase the distance between the second surface 24b and the corresponding separator 25, reserve space for dendrite growth, reduce the risk of dendrites penetrating the separator 25, and further improve the reliability of the battery cell 20; at the same time, the second recess 245 can increase the surface area of ​​the negative electrode sheet 24, and the second recess 245 can provide space for dendrite growth, which can reduce the risk of dendrites piercing the separator 25 on both sides of the thickness direction Z1 of the negative electrode sheet.

[0154] Please refer to Figure 7 According to some embodiments of this application, a second insulating layer 247 is provided at the end of the second protrusion 244 away from the second surface 24b.

[0155] The second protrusion 244 protrudes from the second surface 24b. The second protrusion 244 has a third end and a fourth end, which are disposed opposite to each other in a direction perpendicular to the second surface 24b. The third end is connected to the second protrusion 244, and the fourth end is close to the isolation membrane 25 opposite to the second surface 24b.

[0156] Because the fourth end is close to the separator 25, the second insulating layer 247 can prevent dendrite growth, thereby reducing the risk of dendrites growing too fast and puncturing the separator 25, and further improving the reliability of the battery cell 20.

[0157] According to some embodiments of this application, the second protrusion 244 includes a second end face 2441 and a second outer peripheral face 2442, the second outer peripheral face 2442 surrounds the second end face 2441, and the second outer peripheral face 2442 connects the second end face 2441 and the second surface 24b; the second insulating layer 247 covers the second end face 2441 and part of the second outer peripheral face 2442.

[0158] The second end face 2441 is the end face of the second protrusion 244 that is away from the second surface 24b, and the second outer peripheral surface 2442 is disposed around the edge of the second end face 2441. For example, when the second protrusion 244 has a columnar structure, the second end face 2441 is closer to the separator 25 than the second outer peripheral surface 2442.

[0159] The second insulating layer 247 covers the second end face 2441 and a portion of the second outer peripheral face 2442, such that the portion of the second protrusion 244 near the isolation film 25 is covered by the second insulating layer 247, which can reduce the risk of dendrites growing too fast and puncturing the isolation film 25.

[0160] In the above scheme, the second insulating layer 247 covers the second end face 2441 and part of the second outer peripheral face 2442, further reducing the risk of dendrites forming on the second protrusion 244, thereby improving the reliability of the battery cell 20.

[0161] According to some embodiments of this application, the second insulating layer 247 is a coating or adhesive tape.

[0162] In some embodiments, the second insulating layer 247 is a coating formed by the solidification of an insulating slurry layer. The insulating slurry is applied to the second protrusion 244 by a coating process, which is relatively easy to process.

[0163] In some embodiments, the second insulating layer 247 is adhesive tape, which has a simple structure and is easy to assemble with the second protrusion 244.

[0164] According to some embodiments of this application, the material of the second insulating layer 247 includes polyvinylidene fluoride or an alumina-polyvinylidene fluoride mixture.

[0165] Polyvinylidene fluoride can be applied as an insulating paste to the second protrusion 244 to form a second insulating layer 247.

[0166] The alumina-polyvinylidene fluoride mixture can be applied as an insulating paste to the second protrusion 244 to form the second insulating layer 247.

[0167] According to some embodiments of this application, along the thickness direction Z1 of the negative electrode sheet, the diameter of the projection of the second protrusion 244 is greater than or equal to 0.1 mm and less than or equal to 5 mm.

[0168] When the electrode assembly 22 is a wound structure, the projection of the second protrusion 244 refers to the projection of the second protrusion 244 along the thickness direction Z1 of the negative electrode sheet after the negative electrode sheet 24 is unfolded.

[0169] The diameter of the projection of the second protrusion 244 refers to the diameter of the circumcircle of the projection of the second protrusion 244. For example, if the projection of the second protrusion 244 is a circle, the diameter of the projection of the second protrusion 244 is the outer diameter of the projection of the second protrusion 244.

[0170] Optionally, the diameter of the projection of the second protrusion 244 is the same as the diameter of the projection of the first protrusion 241.

[0171] Optionally, the diameter of the projection of the second protrusion 244 can be any one of 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm or any range between any two.

[0172] In the above scheme, the diameter of the projection of the second protrusion 244 meets the above range. On the one hand, when the diameter of the projection of the second protrusion 244 is greater than or equal to 0.1 mm, it is easy to process and manufacture. On the other hand, when the diameter of the projection of the second protrusion 244 is less than or equal to 5 mm, the second protrusion 244 occupies a smaller area so that the second surface 24b has a larger adhesion area for metal ions, reducing the risk of dendrites piercing the isolation film 25.

[0173] According to some embodiments of this application, there are multiple second protrusions 244, and the multiple second protrusions 244 are arranged in a rectangular array or a rhomboid array.

[0174] Multiple second protrusions 244 are arranged in a rectangular array, which can be distributed at intervals along the length and width directions of the negative electrode plate 24, facilitating the layout of multiple second protrusions 244.

[0175] Multiple second protrusions 244 are arranged in a rhomboid array. For example, the two diagonals of the rhombus can be parallel to the length and width directions of the negative electrode plate 24, respectively, which facilitates the layout of multiple second protrusions 244.

[0176] In the above scheme, multiple second protrusions 244 are arranged in a rectangular or rhomboid array to form multiple support positions between the second surface 24b and the isolation membrane 25, thereby increasing the distance between the second surface 24b and the isolation membrane 25.

[0177] According to some embodiments of this application, the shape of the second protrusion 244 can be the same as the shape of the first protrusion 241, which facilitates processing and manufacturing.

[0178] Please refer to Figure 8 , Figure 8 This is a partial structural schematic diagram of the negative electrode sheet provided in some embodiments of this application. According to some embodiments of this application, the first surface 24a is provided with a plurality of first protrusion groups 2410 and a plurality of second recess groups 2450 arranged alternately along the first direction X1. Each first protrusion group 2410 includes a plurality of first protrusions 241 arranged at intervals along the second direction Y1, and each second recess group 2450 includes a plurality of second recesses 245 arranged at intervals along the second direction Y1. The first direction X1, the second direction Y1, and the thickness direction are perpendicular to each other.

[0179] When the electrode assembly 22 is a stacked structure, the first direction X1 can be parallel to the length direction of the negative electrode 24, and the second direction Y1 can be parallel to the width direction of the negative electrode 24; or, the first direction X1 can be parallel to the width direction of the negative electrode 24, and the second direction Y1 can be parallel to the length direction of the negative electrode 24.

[0180] When the electrode assembly 22 is a wound structure, the first direction X1 can be parallel to the extension direction of the winding axis of the electrode assembly 22, and the second direction Y1 can be the winding direction; or, the first direction X1 can be the winding direction, and the first direction X1 can be parallel to the extension direction of the winding axis of the electrode assembly 22.

[0181] Multiple first protrusion groups 2410 are spaced apart along the first direction X1, and multiple second concave groups 2450 are spaced apart along the first direction X1. The first protrusion groups 2410 and the second concave groups 2450 are staggered in the first direction X1. For example, in the first direction X1, a second concave group 2450 is provided between two adjacent first protrusion groups 2410.

[0182] Please refer to Figure 8 In each first protrusion group 2410, multiple first protrusions 241 are arranged at intervals along the second direction Y1, so that the first protrusions 241 are distributed in a rectangular array.

[0183] Please refer to Figure 8 In each second recess group 2450, multiple second recesses 245 are spaced apart along the second direction Y1, such that the second recesses 245 are distributed in a rectangular array.

[0184] In some embodiments, in each first protrusion group 2410, the distance between two adjacent first protrusions 241 along the second direction Y1 is the same.

[0185] In some embodiments, in each second recess group 2450, the distance between two adjacent second recesses 245 along the second direction Y1 is the same.

[0186] In the above scheme, multiple first protrusion groups 2410 and multiple second concave groups 2450 are alternately arranged on the first surface 24a along the first direction X1, that is, multiple first protrusion groups 2410 and multiple second concave groups 2450 are alternately arranged in the first direction X1, so as to reserve dendrite growth space on both sides of the thickness direction Z1 of the negative electrode sheet and reduce the risk of dendrites piercing the separator 25.

[0187] According to some embodiments of this application, the first protrusion 241 and the second recess 245 are aligned along the second direction Y1.

[0188] Projecting along the thickness direction Z1 of the negative electrode sheet, with the first surface 24a as the projection plane, in the first direction X1, the projection center of the second concave portion 245 is located on the line connecting the projection centers of the corresponding two first convex portions 241; that is, in the first direction X1, the line connecting the projection center of the first convex portion 241 and the projection center of the corresponding second concave portion 245 is parallel to the first direction X1.

[0189] In the above scheme, the first protrusion 241 and the second concave portion 245 are aligned, which facilitates processing and manufacturing.

[0190] According to some embodiments of this application, on the first surface 24a, a plurality of first protrusions 241 and a plurality of second recesses 245 are alternately arranged along a first direction X1, and the plurality of first protrusions 241 and the plurality of second recesses 245 are alternately arranged along a second direction Y1.

[0191] Multiple first protrusions 241 are arranged in a rectangular array, and multiple second concave portions 245 are arranged in a rectangular array. At the same time, the first protrusions 241 and the second concave portions 245 are alternately distributed in the first direction X1 and the second protrusions 241 and the second concave portions 245 are alternately distributed in the second direction Y1.

[0192] In the above scheme, the first protrusion 241 and the second concave portion 245 are staggered, which facilitates the provision of more dendrite growth space on both sides of the thickness direction Z1 of the negative electrode sheet, and reduces the risk of dendrites piercing the separator 25.

[0193] Please refer to Figure 9 , Figure 9 This is a schematic diagram of the through-hole structure of the negative electrode sheet provided in some embodiments of this application. According to some embodiments of this application, the negative electrode sheet 24 is provided with a through-hole 242, which penetrates the negative electrode sheet 24 along the thickness direction Z1 of the negative electrode sheet.

[0194] In some embodiments, the through hole 242 penetrates the two opposing surfaces of the negative electrode current collector 240 in the thickness direction Z1 of the negative electrode sheet, that is, the through hole 242 connects the two opposing surfaces of the negative electrode current collector 240 in the thickness direction Z1 of the negative electrode sheet.

[0195] The negative electrode 24 is provided with a through hole 242, which provides space for dendrite growth, slows down the speed at which dendrites pierce the separator 25, reduces the risk of short circuit between the positive and negative electrodes caused by dendrites penetrating the separator 25, and thus improves the reliability of the battery cell 20.

[0196] Please refer to Figure 8 According to some embodiments of this application, a through hole group 2420 is provided between each first protrusion group 2410 and an adjacent second recess group 2450, and each through hole group 2420 includes a plurality of through holes 242 arranged at intervals along the second direction Y1.

[0197] Along the first direction X1, a through hole group 2420 is provided between adjacent first protrusion group 2410 and second concave group 2450. The negative electrode sheet 24 is provided with various structural forms in the first direction X1 in order to provide growth space for dendrites.

[0198] In each through-hole group 2420, multiple through holes 242 are arranged at intervals along the second direction Y1, and the distance between two adjacent through holes 242 is the same.

[0199] In the above scheme, in the first direction X1, a through hole group 2420 is provided between each first protrusion group 2410 and an adjacent second concave group 2450, so as to increase the dendrite growth space and reduce the risk of dendrites piercing the isolation film 25.

[0200] Please refer to Figure 8 According to some embodiments of this application, along the second direction Y1, the through hole 242 and the first protrusion 241 are offset from each other, and the through hole 242 and the second recess 245 are offset from each other; along the first direction X1, the through hole 242 and the first protrusion 241 are offset from each other, and the through hole 242 and the second recess 245 are offset from each other.

[0201] On the first surface 24a, along the second direction Y1, the projection of the through hole 242 and the projection of the first protrusion 241 are offset from each other, and the center of the projection of the through hole 242 is not on the line connecting the centers of the projections of two adjacent first protrusions 241; along the second direction Y1, the projection of the through hole 242 and the projection of the second recess 245 are offset from each other, and the center of the projection of the through hole 242 is not on the line connecting the centers of the projections of two adjacent second recesses 245.

[0202] On the first surface 24a, along the first direction X1, the projection of the through hole 242 and the projection of the first protrusion 241 are offset from each other, and the center of the projection of the through hole 242 is not on the line connecting the centers of the projections of two adjacent first protrusions 241; along the first direction X1, the projection of the through hole 242 and the projection of the second concave portion 245 are offset from each other, and the center of the projection of the through hole 242 is not on the line connecting the centers of the projections of two adjacent second concave portions 245.

[0203] The distribution of the through hole 242, the first protrusion 241 and the second concave portion 245 occupies a small area of ​​the first surface 24a, leaving space for metal ion growth, and has little impact on the energy density of the battery cell 20.

[0204] In the above scheme, the first protrusion 241 and the second concave portion 245 are respectively staggered from the through hole 242, which makes the processing and manufacturing process easier and more convenient.

[0205] According to some embodiments of this application, there are multiple through holes 242, and the multiple through holes 242 are arranged in a rectangular array or a diamond array.

[0206] Multiple through holes 242 are arranged in a rectangular array, which can be distributed at intervals along the length and width of the negative electrode plate 24, facilitating the layout of multiple through holes 242.

[0207] Multiple through holes 242 are arranged in a rhomboid array. For example, the two diagonals of the rhombus can be parallel to the length and width directions of the negative electrode plate 24, respectively, which facilitates the layout of multiple through holes 242.

[0208] In the above scheme, the multiple through holes 242 are arranged in a rectangular or rhomboid array, which facilitates processing and manufacturing, and can provide more space for dendrite growth, reducing the risk of dendrites piercing the isolation film 25.

[0209] According to some embodiments of this application, there are multiple through holes 242, and the ratio of the total area of ​​all through holes 242 to the area of ​​the first surface 24a is greater than or equal to 3% and less than or equal to 25%.

[0210] In some embodiments, the area of ​​the through hole 242 can be measured by an image sensor. For example, the negative electrode 24 can be photographed by an industrial camera along the thickness direction Z1 of the negative electrode sheet, and the area of ​​the through hole 242 can be measured based on the acquired image information.

[0211] The area of ​​the first surface 24a is the length of the negative electrode 24 multiplied by its width, without excluding the area of ​​the through hole 242.

[0212] For ease of measurement, the ratio of the total area of ​​all through holes 242 within a unit square centimeter to the area of ​​the first surface 24a can be expressed as the total area of ​​all through holes 242. For example, a negative electrode sheet 24 within a unit square centimeter can be selected, and the total area Amm of all through holes 242 within that unit square centimeter can be measured. 2 The ratio of the total area of ​​all through holes 242 to the area of ​​the first surface 24a is A.

[0213] Optionally, the ratio of the total area of ​​all through holes 242 to the area of ​​the first surface 24a is greater than or equal to 5% and less than or equal to 20%.

[0214] Optionally, the ratio of the total area of ​​all through holes 242 to the area of ​​the first surface 24a can be any one of 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25% or any range between any two.

[0215] In the above scheme, the ratio of the total area of ​​the through hole 242 to the area of ​​the first surface 24a satisfies the above relationship. On the one hand, when the ratio of the total area of ​​the through hole 242 to the area of ​​the first surface 24a is greater than or equal to 3%, the surface area of ​​the negative electrode 24 can be increased, and the dendrite growth space can be increased. On the other hand, when the ratio of the total area of ​​the through hole 242 to the area of ​​the first surface 24a is less than or equal to 25%, it occupies a smaller area and has a smaller impact on the energy density.

[0216] According to some embodiments of this application, the battery cell 20 is a metal battery cell.

[0217] According to some embodiments of this application, this application also provides a battery 100, which includes a battery cell 20 as provided in any of the above embodiments.

[0218] According to some embodiments of this application, this application also provides an electrical device, which includes a battery cell 20 or a battery 100 as provided in any of the above embodiments, the battery cell 20 or the battery 100 being used to provide electrical energy.

[0219] According to some embodiments of this application, please refer to Figures 3 to 9 This application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, and an electrode terminal 212a.

[0220] The housing 21 includes a housing 211 and an end cap 212. The housing 211 has an opening, and the end cap 212 closes the opening. An electrode terminal 212a is disposed on the end cap 212, and an electrode assembly 22 is disposed inside the housing 21. The electrode assembly 22 has tabs that are electrically connected to the electrode terminal 212a.

[0221] The electrode assembly 22 includes a positive electrode 23, a negative electrode 24, and a separator 25, with the separator 25 disposed between the positive electrode 23 and the negative electrode 24. The negative electrode 24 has a first surface 24a and a second surface 24b disposed opposite each other in the thickness direction. The first surface 24a has a first protrusion 241 facing the separator 25 on the thickness direction Z1 side of the negative electrode. The second surface 24b has a first recess 243 recessed into the first surface 24a, the position of which corresponds to the position of the first protrusion 241. The second surface 24b also has a second protrusion 244 facing the separator 25 on the other side of the thickness direction Z1 of the negative electrode. The first surface 24a has a second recess 245 recessed into the second surface 24b, the position of which corresponds to the position of the second protrusion 244.

[0222] The negative electrode 24 is provided with a through hole 242, which penetrates the negative electrode 24 along the thickness direction Z1 of the negative electrode 24.

[0223] The first surface 24a is provided with a plurality of first protrusion groups 2410 and a plurality of second recess groups 2450 arranged alternately along the first direction X1. Each first protrusion group 2410 includes a plurality of first protrusions 241 arranged at intervals along the second direction Y1. Each second recess group 2450 includes a plurality of second recesses 245 arranged at intervals along the second direction Y1. A through hole group 2420 is provided between each first protrusion group 2410 and an adjacent second recess group 2450. Each through hole group 2420 includes a plurality of through holes 242 arranged at intervals along the second direction Y1.

[0224] According to the embodiments of this application, the battery cell 20 has a first protrusion 241 and a second protrusion 244 respectively provided on both sides of the negative electrode sheet in the thickness direction Z1, so that there is a large distance between the negative electrode sheet 24 and the two adjacent separators 25. In addition, with the provision of through holes 242, more space for dendrite growth can be provided, reducing the risk of dendrites piercing the separator 25 and improving the reliability of the battery cell 20.

[0225] 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: shell; An electrode assembly is disposed within the housing. The electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the positive electrode and the negative electrode. In the thickness direction of the negative electrode sheet, the negative electrode sheet has a first surface facing the separator, and the first surface is provided with a first protrusion.

2. The battery cell according to claim 1, characterized in that, A first insulating layer is provided at the end of the first protrusion away from the first surface.

3. The battery cell according to claim 2, characterized in that, The first protrusion includes a first end face and a first outer peripheral face, the first outer peripheral face surrounds the first end face, and the first outer peripheral face connects the first end face and the first surface. The first insulating layer covers the first end face and part of the first outer peripheral face.

4. The battery cell according to claim 2, characterized in that, The first insulating layer is a coating or adhesive tape.

5. The battery cell according to claim 2, characterized in that, The material of the first insulating layer includes polyvinylidene fluoride or a mixture of alumina and polyvinylidene fluoride.

6. The battery cell according to claim 1, characterized in that, Along the thickness direction of the negative electrode sheet, the diameter of the projection of the first protrusion is greater than or equal to 0.1 mm and less than or equal to 5 mm.

7. The battery cell according to claim 1, characterized in that, The number of the first protrusions is multiple, and the multiple first protrusions are arranged in a rectangular array or a diamond array.

8. The battery cell according to claim 1, characterized in that, The first protrusion is cylindrical, frustum-shaped, or hemispherical.

9. The battery cell according to claim 1, characterized in that, The negative electrode sheet also has a second surface, the second surface and the first surface are disposed opposite to each other along the thickness direction of the negative electrode sheet, the second surface is provided with a first recess that is recessed into the first surface, and the position of the first recess corresponds to the position of the first protrusion.

10. The battery cell according to claim 9, characterized in that, The second surface is provided with a second protrusion, and the first surface is provided with a second recess that is recessed into the second surface, the position of the second recess corresponding to the position of the second protrusion.

11. The battery cell according to claim 10, characterized in that, A second insulating layer is provided at the end of the second protrusion away from the second surface.

12. The battery cell according to claim 10, characterized in that, The number of the second protrusions is multiple, and the multiple second protrusions are arranged in a rectangular array or a diamond array.

13. The battery cell according to claim 10, characterized in that, The first surface is provided with a plurality of first protrusion groups and a plurality of second concave groups arranged alternately along a first direction. Each first protrusion group includes a plurality of first protrusions arranged at intervals along a second direction, and each second concave group includes a plurality of second concaves arranged at intervals along the second direction. The first direction, the second direction and the thickness direction are perpendicular to each other.

14. The battery cell according to claim 13, characterized in that, Along the second direction, the first protrusion and the second concave portion are aligned.

15. The battery cell according to claim 13, characterized in that, On the first surface, a plurality of first protrusions and a plurality of second recesses are alternately arranged along the first direction, and a plurality of first protrusions and a plurality of second recesses are alternately arranged along the second direction.

16. The battery cell according to claim 13, characterized in that, A through-hole group is provided between each of the first protrusion groups and an adjacent second recess group, each of the through-hole groups including a plurality of through holes arranged at intervals along the second direction, the through holes penetrating the negative electrode sheet along the thickness direction of the negative electrode sheet.

17. The battery cell according to claim 16, characterized in that, Along the second direction, the through hole and the first protrusion are offset from each other, and the through hole and the second recess are offset from each other; Along the first direction, the through hole and the first protrusion are offset from each other, and the through hole and the second recess are offset from each other.

18. The battery cell according to claim 1, characterized in that, The negative electrode sheet is provided with a through hole, which penetrates the negative electrode sheet along the thickness direction.

19. The battery cell according to claim 18, characterized in that, The number of through holes is multiple, and the multiple through holes are arranged in a rectangular array or a diamond array.

20. The battery cell according to claim 18, characterized in that, The number of through holes is multiple, and the ratio of the total area of ​​all through holes to the area of ​​the first surface is greater than or equal to 3% and less than or equal to 25%.

21. The battery cell according to claim 20, characterized in that, The battery cell is a metal battery cell.

22. A battery, characterized in that, Includes the battery cell as described in any one of claims 1-21.

23. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-21 or a battery as described in claim 22, wherein the battery cell or the battery is used to provide electrical energy.

Images