Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power consumption device. The battery monomer comprises a shell, an electrode assembly and at least one insulating tape. The electrode assembly is accommodated in the shell. The electrode assembly comprises a first pole piece, a second pole piece and a diaphragm. The first pole piece and the second pole piece are opposite in polarity. The diaphragm is arranged on both sides of the first pole piece and both sides of the second pole piece. The electrode assembly is in a winding shape. The first pole piece comprises a first extension part. The diaphragm of the innermost circle comprises a second extension part. Along the winding direction of the electrode assembly, the first extension part and the second extension part exceed the end part of the innermost circle of the second pole piece. At least part of the at least one insulating tape is attached to both sides of the first extension part and the second extension part away from each other, so as to limit the relative displacement of at least part of the second extension part and the first extension part. The battery monomer provided by the application is beneficial to reducing the risk of internal short circuit of the battery monomer caused by the contact between the second extension part of the first pole piece and the second pole piece, and is beneficial to improving the reliability of the battery monomer.

Description

Technical Field

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

[0003] In the development of battery cell technology, in addition to improving the performance of battery cells, their reliability is also a crucial consideration. Therefore, improving the reliability of battery cells is a continuous challenge in battery cell technology. Summary of the Invention

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

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

[0006] In a first aspect, the battery cell provided in this application includes a casing, an electrode assembly, and at least one insulating tape. The electrode assembly is housed within the casing and includes a first electrode, a second electrode, and a separator. The first and second electrodes have opposite polarities, and the separator is disposed on both sides of the first and second electrodes. The electrode assembly is wound, with the first electrode including a first extension and the innermost separator including a second extension. Along the winding direction of the electrode assembly, the first and second extensions extend beyond the end of the innermost circle of the second electrode. At least a portion of the insulating tape is affixed to the opposite sides of the first and second extensions to limit the relative displacement between at least a portion of the second extension and the first extension.

[0007] The battery cell provided in this application embodiment restricts the relative displacement between at least a portion of the second extension and the first extension by attaching at least one insulating tape to the first extension. This reduces the possibility of the second extension of the innermost separator folding or shifting relative to the first extension of the first electrode, thereby reducing the risk of internal short circuit caused by the contact between the second extension of the first electrode and the second electrode, which is beneficial to improving the reliability of the battery cell.

[0008] According to some embodiments of this application, insulating tape covers at least a portion of the ends of the first extension and the second extension along the winding direction.

[0009] In the above solution, by setting insulating tape to cover at least a portion of the ends of the first extension and the second extension along the winding direction, it is beneficial to reduce the risk of burrs at the end of the first extension puncturing the separator and causing a short circuit inside the battery cell. At the same time, it is also beneficial to further reduce the risk of the second extension folding or shifting relative to the first extension, and further beneficial to reduce the risk of the first extension contacting the second electrode.

[0010] According to some embodiments of this application, the insulating tape includes a first part, a second part, and a connecting part. The first part is attached to the side of the first extension that is opposite to the second extension, and the second extension that is opposite to the first extension. The connecting part connects the first part and the second part.

[0011] In the above solution, the process of bonding the insulating tape to the first extension and the second extension is facilitated, and by providing a connecting part to cover the ends of the first extension and the second extension, the risk of burrs at the end of the first extension puncturing the separator and causing a short circuit inside the battery cell is reduced.

[0012] According to some embodiments of this application, at least one insulating tape includes at least two insulating tapes, each including a first insulating tape and a second insulating tape. The first insulating tape is applied to the side of the first extension opposite to the second extension, and the second insulating tape is applied to the side of the second extension opposite to the first extension. The first and second insulating tapes extend beyond the ends of the first and second extensions and are bonded together.

[0013] In the above solution, by setting the first insulating tape and the second insulating tape, it is easy to bond the insulating tape to the first extension and the second extension respectively. By bonding the portions of the first insulating tape and the second insulating tape that extend beyond the first extension and the second extension, the relative displacement between the first extension and the second extension is restricted, and the ends of the first extension and the second extension are covered, which helps to reduce the risk of internal short circuits in the battery cell.

[0014] According to some embodiments of this application, insulating tape covers the ends of the first extension and the second extension that are away from the second electrode sheet along the winding direction. The first electrode sheet includes a functional area coated with an active material layer and an empty foil area uncoated with an active material layer, the empty foil area being disposed on one side of the functional area along a first direction, which intersects the winding direction. At least one end of the insulating tape extends beyond the functional area along the first direction.

[0015] In the above solution, insulating tape can be used to provide a certain covering effect on the end of the functional area along the first direction, so as to reduce the risk of burrs on the end of the functional area along the first direction puncturing the diaphragm.

[0016] According to some embodiments of this application, along the first direction, the distance h of the insulating tape extending beyond the functional area satisfies: 1mm ≤ h ≤ 4mm.

[0017] In the above scheme, by setting 1mm≤h≤4mm, it is beneficial to improve the coverage of the insulating tape on the end of the functional area along the first direction, thereby reducing the risk of burrs on the end of the functional area along the first direction damaging the separator, and at the same time, it is also beneficial to improve the energy density of the battery cell.

[0018] According to some embodiments of this application, 2mm ≤ h ≤ 3mm.

[0019] In the above scheme, by setting 2mm≤h≤3mm, it is beneficial to further improve the coverage of the insulating tape on the end of the functional area along the first direction, further reduce the risk of burrs on the end of the functional area along the first direction damaging the diaphragm, and also to further improve the energy density of the battery cell.

[0020] According to some embodiments of this application, the innermost ends of the first extension and the second extension are flush with each other along the winding direction.

[0021] In the above scheme, after the electrode assembly winding process is completed, the first electrode sheet can be cut together with the innermost diaphragm, which helps to simplify the production process of the electrode assembly.

[0022] According to some embodiments of this application, the first electrode is a negative electrode and the second electrode is a positive electrode.

[0023] In the above scheme, during the charging process of the battery cell, the lithium ions and other metal ions released from the positive electrode are always received by the negative electrode, which helps to reduce the risk of lithium plating between the electrodes.

[0024] According to some embodiments of this application, the insulating tape includes a substrate layer and an adhesive layer. The adhesive layer bonds the substrate layer to a first extension and bonds the substrate layer to a second extension. The adhesive layer includes polyethylene adhesive.

[0025] In the above scheme, during the cycle operation of the battery cell, metal ions such as lithium ions can pass through the insulating tape more smoothly, which is beneficial to improving the dynamic performance of the battery cell and reducing the risk of lithium plating in the electrode assembly.

[0026] Secondly, the battery device provided in the embodiments of this application includes the battery cell provided in any of the above embodiments.

[0027] The battery device provided in this application has the same technical effect as the battery cell provided in any of the above embodiments, and will not be described again here.

[0028] Thirdly, the electrical device provided in the embodiments of this application includes the battery device provided in the above embodiments, and the battery device is used to provide electrical energy.

[0029] The electrical device provided in this application embodiment has the same technical effect as the battery device provided in this application embodiment, and will not be described again here.

[0030] 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

[0031] 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.

[0032] Figure 1 This is a schematic diagram of the vehicle structure provided in an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application;

[0034] Figure 3 This is a schematic diagram of the structure of a battery cell assembly in a battery device provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of the exploded structure of a single battery cell in a battery device provided in an embodiment of this application;

[0036] Figure 5 This is a cross-sectional view of the electrode assembly in a battery cell provided in an embodiment of this application.

[0037] Figure 6 for Figure 5 A magnified view of a section at point A in the middle;

[0038] Figure 7 This is a schematic diagram of a portion of the structure of a battery cell in an unfolded state, as provided in an embodiment of this application.

[0039] Figure 8 This is a schematic diagram of a portion of the structure of a battery cell provided in an embodiment of this application.

[0040] The accompanying drawings are not necessarily drawn to scale.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1-Vehicle; 1a-Motor; 1b-Controller;

[0043] 10 - Battery assembly; 11 - Housing; 111 - First sub-housing; 112 - Second sub-housing;

[0044] 20-Battery cell module;

[0045] 30-Battery cell; 31-Casing; 311-Housing shell; 312-End cap; 32-Electrode assembly; 321-Electrode body; 322-Taper; 33-Electrode terminal;

[0046] 41-First electrode; 411-First extension; 41a-Functional area; 41b-Empty foil area; 42-Second electrode; 43-Diaphragm; 431-Second extension;

[0047] 50 - Insulating tape; 50a - First insulating tape; 50b - Second insulating tape; 51 - First part; 52 - Second part; 53 - Connecting part;

[0048] X - winding direction; Y - first direction. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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).

[0055] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0056] 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, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0057] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0058] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0059] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0060] 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.

[0061] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0062] 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.

[0063] The battery cell may be, but is not limited to, lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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, carbon electrodes, 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.).

[0068] 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 battery cells may also be used.

[0069] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0070] 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, copper, aluminum, carbon electrode, carbon, nickel, or titanium, etc.

[0071] In some embodiments, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0072] As an example, the negative electrode active material 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.

[0073] In some embodiments, the diaphragm 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.

[0074] 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.

[0075] In some embodiments, the membrane is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0076] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0077] 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.

[0078] 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.

[0079] 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 through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0080] 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.

[0081] As an example, the 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. There are no particular limitations in the embodiments of this application.

[0082] The electrode assembly of a battery cell typically includes a positive electrode, a negative electrode, and a separator. The positive electrode, negative electrode, and separator are formed into the electrode assembly through a winding process. During the winding process, the positive electrode, negative electrode, and separator are wound together on a winding needle. During the winding process or when the winding needle is pulled out after winding, the separator moves or folds relative to the positive and negative electrodes, resulting in some positive and negative electrodes not having a separator between them. This can easily cause the positive and negative electrodes inside the electrode assembly to come into contact with each other, thereby creating a risk of internal short circuit in the battery cell and seriously affecting the reliability of the battery cell.

[0083] In view of this, the battery cell provided in this application embodiment includes a casing, an electrode assembly, and at least one insulating tape. The electrode assembly is housed within the casing and includes a first electrode, a second electrode, and a separator. The first and second electrodes have opposite polarities, and the separator is disposed on both sides of the first and second electrodes. The electrode assembly is wound, with the first electrode including a first extension and the innermost separator including a second extension. Along the winding direction of the electrode assembly, the first and second extensions extend beyond the end of the innermost circle of the second electrode. At least a portion of the insulating tape is applied to the opposite sides of the first and second extensions to limit the relative displacement between at least a portion of the second extension and the first extension.

[0084] The battery cell provided in this application embodiment restricts the relative displacement between at least a portion of the second extension and the first extension by attaching at least one insulating tape to the first extension. This reduces the possibility of the second extension of the innermost separator folding or shifting relative to the first extension of the first electrode, thereby reducing the risk of internal short circuit caused by the contact between the second extension of the first electrode and the second electrode, which is beneficial to improving the reliability of the battery cell.

[0085] The technical solutions described in the embodiments of this application are applicable to battery cells, battery packs including battery cells, and electrical devices using battery devices.

[0086] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using the battery device disclosed in this application.

[0087] 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.

[0088] For ease of explanation, the following embodiments will be described using a vehicle 1 as an example of an electrical device according to an embodiment of this application.

[0089] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1 provided in an embodiment of this application. Vehicle 1 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 device 10 is installed inside vehicle 1, and the battery device 10 can be located at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1; for example, the battery device 10 can serve as the operating power source for vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation of vehicle 1.

[0090] The vehicle 1 may also include a controller 1b and a motor 1a. The controller 1b is used to control the battery device 10 to supply power to the motor 1a, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0091] In some embodiments of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0092] Please refer to Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the structure of the battery device 10 provided in the embodiments of this application. Figure 3 This is an exploded view of the battery cell 30 provided in an embodiment of this application. The battery device 10 includes a housing 11 and a battery cell 30, with the battery cell 30 housed within the housing 11. The housing 11 provides a space for the battery cell 30, and the housing 11 can have various structures. In some embodiments, the housing 11 may include a first sub-housing 111 and a second sub-housing 112, which overlap each other, and together define a space for accommodating the battery cell 30. The second sub-box 112 can be a hollow structure with one end open, and the first sub-box 111 can be a plate-like structure. The first sub-box 111 covers the opening side of the second sub-box 112 so that the first sub-box 111 and the second sub-box 112 together define the accommodating space. Alternatively, the first sub-box 111 and the second sub-box 112 can both be hollow structures with one side open, and the opening side of the first sub-box 111 covers the opening side of the second sub-box 112.

[0093] In the battery device 10, there can be multiple battery cells 30, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 30 are connected in both series and parallel configurations. Multiple battery cells 30 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 30 is housed within the housing 11. Alternatively, the battery device 10 can also consist of multiple battery cells 30 first connected in series, parallel, or in a mixed manner to form a battery cell assembly 20, and then the multiple battery cell assemblies 20 are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 11. The battery device 10 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 30.

[0094] Among them, the battery cell 30 can be a secondary battery or a primary battery; the battery cell 30 can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0095] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the exploded structure of a battery cell 30 provided in an embodiment of this application. Figure 4As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, and electrode terminals 33. The housing 31 includes a casing 311 and an end cap 312. The casing 311 has an opening, and the end cap 312 closes the opening to isolate the internal environment of the battery cell 30 from the external environment.

[0096] The housing 311 is a component used to cooperate with the end cap 312 to form the internal environment of the battery cell 30, wherein the formed internal environment can accommodate the electrode assembly 32, electrolyte, and other components. The housing 311 and the end cap 312 can be independent components. The housing 311 can have various shapes and sizes. Specifically, the shape of the housing 311 can be determined according to the specific shape and size of the electrode assembly 32. The housing 311 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0097] End cap 312 refers to a component that covers the opening of housing 311 to isolate the internal environment of battery cell 30 from the external environment. The shape of end cap 312 can be adapted to the shape of housing 311 to fit it. Optionally, end cap 312 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 312 is not easily deformed under pressure and impact, giving battery cell 30 higher structural strength and improved reliability. Functional components such as electrode terminals 33 can be provided on end cap 312. Electrode terminals 33 can be used for electrical connection with electrode assembly 32 to output or input electrical energy to battery cell 30. The material of end cap 312 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating structure may be provided on the inner side of the end cap 312. The insulating structure can be used to isolate the electrical connection components within the housing 311 from the end cap 312 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0098] Electrode assembly 32 is the component in the battery cell 30 where electrochemical reactions occur. The housing 311 may contain one or more electrode assemblies 32. The electrode assembly 32 is mainly formed by winding or stacking positive and negative electrode plates, and typically a separator is provided between the positive and negative electrode plates to separate them and prevent internal short circuits. The portions of the positive and negative electrode plates containing active material constitute the electrode body 321 of the electrode assembly 32, while the portions of the positive and negative electrode plates without active material each constitute a tab 322. The positive and negative tabs may be located together at one end of the electrode body 321 or separately at both ends of the electrode body 321. During the charging and discharging process of the battery cell 30, the positive and negative active materials react with the electrolyte, and the tabs 322 connect to the electrode terminals 33 to form a current loop.

[0099] Firstly, such as Figure 4 and Figure 5 As shown, the battery cell 30 provided in this embodiment includes a housing 31, an electrode assembly 32, and at least one insulating tape 50. The electrode assembly 32 is housed within the housing 31 and includes a first electrode 41, a second electrode 42, and a separator 43. The first electrode 41 and the second electrode 42 have opposite polarities, and the separator 43 is disposed on both sides of the first electrode 41 and the second electrode 42. The electrode assembly 32 is wound in shape. The first electrode 41 includes a first extension 411, and the innermost separator 43 includes a second extension 431. Along the winding direction X of the electrode assembly 32, the first extension 411 and the second extension 431 extend beyond the end of the innermost circle of the second electrode 42. At least a portion of the insulating tape 50 is attached to the opposite sides of the first extension 411 and the second extension 431 to limit the relative displacement between at least a portion of the second extension 431 and the first extension 411.

[0100] Optionally, the first electrode 41 can be set as the positive electrode and the second electrode 42 as the negative electrode; or, the first electrode 41 can be set as the negative electrode and the second electrode 42 as the positive electrode. A diaphragm 43 is disposed on both sides of the first electrode 41 and both sides of the second electrode 42, so that any two adjacent first electrodes 41 and second electrodes 42 are separated by a diaphragm 43, which provides insulation for the first electrodes 41 and the second electrodes 42.

[0101] If the electrode assembly 32 is wound, it can optionally be wound into a cylindrical shape, or the electrode assembly 32 can be shaped into a polygonal prism shape after being wound.

[0102] Since both sides of the first electrode 41 and both sides of the second electrode 42 have diaphragms 43, the innermost diaphragm 43 is located on the side of the second electrode 42 facing away from the first electrode 41. Thus, the first electrode 41 and the innermost diaphragm 43 are located on both sides of the second electrode 42, respectively. The insulating adhesive layer is disposed at any position of the first extension 411 and the second extension 431, which can provide a certain covering effect on the innermost end of the second electrode 42, thereby reducing the risk of short circuit due to contact between the first electrode 41 and the second electrode 42.

[0103] The battery cell 30 may include one, two or more insulating tapes 50. One end of an insulating tape 50 may be attached to the side of the first extension 411 away from the second extension 431, and after being bent, the other end may be attached to the side of the second extension 431 away from the first extension 411. In this way, the first extension 411 and the second extension 431 are respectively connected to the same insulating tape 50, and the insulating tape 50 limits the risk of the second extension 431 being folded or displaced relative to the first extension 411.

[0104] Alternatively, an insulating tape 50 can be applied to the side of the first extension 411 opposite to the second extension 431 and extending beyond the ends of the first extension 411 and the second extension 431. Another insulating tape 50 can be applied to the side of the second extension 431 opposite to the first extension 411 and extending beyond the same end of the second extension 431 and the first extension 411. The portions of the two insulating tapes 50 extending beyond the ends of the first extension 411 and the second extension 431 are bonded together. In this way, the risk of relative displacement of the first extension 411 and the second extension 431 can be limited by the two insulating tapes 50.

[0105] Along the winding direction X, the ends of the first extension 411 and the second extension 431 that are away from the second electrode 42 can be flush with each other, or the end of the second extension 431 that is away from the second electrode 42 can extend beyond the end of the first extension 411 that extends beyond the electrode. This can be selected according to actual needs.

[0106] Optionally, the insulating tape 50 may be applied to the ends of the first extension 411 and the second extension 431 along the winding direction X, and cover at least a portion of the ends of the first extension 411 and the second extension 431 along the winding direction X away from the second electrode 42. Alternatively, the insulating tape 50 may be applied to the area between the two ends of the first extension 411 and the second extension 431 along the winding direction X, and cover at least a portion of at least one end of the first extension 411 and the second extension 431 perpendicular to the winding direction X.

[0107] Optionally, insulating tape 50 may be provided at one location of the first extension 411 and the second extension 431, or insulating tape 50 may be provided at at least two locations of the first extension 411 and the second extension 431.

[0108] Insulating tape 50 is applied to the opposite sides of the first extension 411 and the second extension 431 to limit the relative displacement between the portion of the second extension 431 and the portion of the first extension 411 to the end of the second electrode 42. Thus, the first extension 411 and the second extension 431 have a certain covering effect on the end of the second electrode 42, thereby reducing the risk of internal short circuit in the battery cell 30 caused by contact between the first electrode 41 and the second electrode 42.

[0109] Optionally, the insulating tape 50 may be applied only to the first extension 411 and the second extension 431, or the insulating tape 50 may be applied partly to the first extension 411 and the second extension 431, and another part to the areas where the first electrode 41 and the diaphragm 43 are adjacent to the first extension 411 and the second extension 431, respectively. In this way, the insulating tape 50 fixes the diaphragm 43 and the second electrode on both sides of the innermost end of the second electrode 42, so as to provide a certain covering effect on the innermost end of the second electrode 42 and reduce the risk of the first electrode 41 and the second electrode 42 coming into contact with each other.

[0110] It is understood that the electrode assembly 32 may include multiple positive electrode plates and multiple negative electrode plates, and the first electrode plate 41 and the second electrode plate 42 may be the innermost positive electrode plate and the negative electrode plate, respectively.

[0111] The battery cell 30 provided in this application embodiment, by attaching at least one insulating tape 50 to the first extension 411 and the second extension 431, restricts the relative displacement between at least a portion of the second extension 431 and the first extension 411, reduces the possibility of the second extension 431 of the innermost separator 43 folding or shifting relative to the first extension 411 of the first electrode 41, thereby reducing the risk of the second extension 431 of the first electrode 41 contacting the second electrode 42 and causing an internal short circuit in the battery cell 30, which is beneficial to improving the reliability of the battery cell 30.

[0112] In some embodiments, such as Figure 5 As shown, the insulating tape 50 covers at least a portion of the ends of the first extension 411 and the second extension 431 along the winding direction X.

[0113] Optionally, the insulating tape 50 may cover the entire ends of the first extension 411 and the second extension 431 along the winding direction X, or the insulating tape 50 may cover a portion of the ends of the first extension 411 and the second extension 431 along the winding direction X.

[0114] It is understandable that the innermost end of the first extension 411 of the first electrode 41 is the cut end of the first electrode 41, which will inevitably produce certain burrs. By covering the ends of the first extension 411 and the second extension 431 with insulating glue, it is beneficial to reduce the risk of the burrs at the end of the first extension 411 piercing the separator 43 and causing an internal short circuit in the battery cell 30.

[0115] Furthermore, the insulating tape 50 connects the ends of the first extension 411 and the second extension 431 along the winding direction X, which can limit the relative displacement of the first extension 411 and the second extension 431 to the greatest extent, reduce the risk of relative displacement at the ends of the first extension 411 and the second extension 431, and further reduce the risk of short circuit between the first electrode 41 and the second electrode 42.

[0116] Therefore, by covering at least a portion of the ends of the first extension 411 and the second extension 431 along the winding direction X with insulating tape 50, it is beneficial to reduce the risk of burrs at the end of the first extension 411 puncturing the separator 43 and causing an internal short circuit in the battery cell 30. At the same time, it is also beneficial to further reduce the risk of the second extension 431 folding or shifting relative to the first extension 411, and further beneficial to reduce the risk of the first extension 411 contacting the second electrode 42.

[0117] In some embodiments, such as Figure 5 and Figure 6 As shown, the insulating tape 50 includes a first part 51, a second part 52 and a connecting part 53. The first part 51 is attached to the side of the first extension 411 opposite to the second extension 431. The connecting part 53 connects the first part 51 and the second part 52.

[0118] Thus, the first part 51 and the second part 52 are bent relative to the connecting part 53, and the first part 51 and the second part 52 are respectively attached to the opposite sides of the first extension 411 and the second extension 431. The first part 51 and the second part 52 are connected by the connecting part 53 to limit the relative displacement of the second extension 431 and the first extension 411.

[0119] Optionally, the connecting portion 53 may cover the ends of the first extension 411 and the second extension 431 along the winding direction X, or the connecting portion 53 may cover the ends of the first extension 411 and the second extension 431 perpendicular to the winding direction X, which can be selected as needed.

[0120] Therefore, this arrangement facilitates the bonding process of the insulating tape 50 to the first extension 411 and the second extension 431, and by providing the connecting part 53 to cover the ends of the first extension 411 and the second extension 431, it helps to reduce the risk of burrs at the end of the first extension 411 puncturing the separator 43 and causing an internal short circuit in the battery cell 30.

[0121] In some embodiments, such as Figure 7 As shown, at least one insulating tape 50 includes at least two insulating tapes 50, each including a first insulating tape 50a and a second insulating tape 50b. The first insulating tape 50a is applied to the side of the first extension 411 opposite to the second extension 431, and the second insulating tape 50b is applied to the side of the second extension 431 opposite to the first extension 411. The first insulating tape 50a and the second insulating tape 50b extend beyond the ends of the first extension 411 and the second extension 431 and are bonded together.

[0122] Thus, a portion of the first insulating tape 50a and a portion of the second insulating tape 50b are respectively bonded to the first extension 411 and the second extension 431, while the remaining portions extend beyond the first extension 411 and the second extension 431 and are bonded to each other. Together, the first insulating tape 50a and the second insulating tape 50b provide a certain degree of coverage to the ends of the first extension 411 and the second extension 431, thereby reducing the risk of burrs at the end of the first extension 411 puncturing the diaphragm 43.

[0123] By providing the first insulating tape 50a and the second insulating tape 50b, it is convenient to bond the insulating tape 50 to the first extension 411 and the second extension 431 respectively. By bonding the portions of the first insulating tape 50a and the second insulating tape 50b that extend beyond the first extension 411 and the second extension 431, the relative displacement between the first extension 411 and the second extension 431 is restricted, and the ends of the first extension 411 and the second extension 431 are covered, which helps to reduce the risk of internal short circuits in the battery cell 30.

[0124] In some embodiments, such as Figure 8 As shown, the insulating tape 50 covers the ends of the first extension 411 and the second extension 431 that are away from the second electrode 42 along the winding direction X. The first electrode 41 includes a functional region 41a coated with an active material layer and an empty foil region 41b uncoated with an active material layer. The empty foil region 41b is located on one side of the functional region 41a along a first direction Y, which intersects the winding direction X. At least one end of the insulating tape 50 extends beyond the functional region 41a along the first direction Y.

[0125] The insulating tape 50 covers the ends of the first extension 411 and the second extension 431 away from the second electrode 42 along the winding direction X. The insulating tape 50 has a certain covering effect on the innermost end of the first extension 411 along the winding direction X, so as to reduce the risk of burrs at the innermost end of the first electrode 41 puncturing the diaphragm 43.

[0126] The functional region 41a of the first electrode 41 can be a region where metal ions such as lithium ions are repeatedly inserted and removed, while the empty foil region 41b can be a part of the first electrode 41 that constitutes the tab 322. Therefore, the first direction Y can be the direction from which the tab 322 of the electrode assembly 32 is led out.

[0127] Since the functional area 41a is coated with an active material layer, its ends will inevitably produce certain burrs. At least one end of the insulating tape 50 along the first direction Y is set to extend beyond the functional area 41a. Optionally, one end of the insulating tape 50 along the first direction Y can be set to extend beyond the functional area 41a, or both ends of the insulating tape 50 along the first direction Y can be set to extend beyond the functional area 41a.

[0128] In this way, the insulating tape 50 can provide a certain covering effect on the end of the functional area 41a along the first direction Y, thereby reducing the risk of burrs on the end of the functional area 41a along the first direction Y puncturing the diaphragm 43.

[0129] In some embodiments, such as Figure 8 As shown, along the first direction Y, the distance h of the insulating tape 50 extending beyond the functional area 41a satisfies: 1mm≤h≤4mm.

[0130] Optionally, h can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm or 4mm, etc.

[0131] It is understandable that the greater the length of h, the better it is to improve the coverage of the end of the functional area 41a along the first direction Y by the insulating tape 50, while the smaller the size of h, the better it is to reduce the space occupied by the insulating tape 50 inside the battery cell 30, so as to improve the energy density of the battery cell 30.

[0132] After systematic analysis and long-term practice, the inventors discovered that by setting 1mm≤h≤4mm, it is beneficial to improve the covering effect of the insulating tape 50 on the end of the functional area 41a along the first direction Y, thereby reducing the risk of burrs on the end of the functional area 41a along the first direction Y damaging the separator 43, and at the same time, it is also beneficial to improve the energy density of the battery cell 30.

[0133] In some embodiments, 2mm ≤ h ≤ 3mm.

[0134] Optionally, h can be 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, or 3mm, etc.

[0135] After further systematic analysis and long-term practice, the inventors discovered that by setting 2mm≤h≤3mm, it is beneficial to further improve the covering effect of the insulating tape 50 on the end of the functional area 41a along the first direction Y, further reduce the risk of burrs on the end of the functional area 41a along the first direction Y puncturing the diaphragm 43, and also to further improve the energy density of the battery cell 30.

[0136] In some embodiments, such as Figure 5 and Figure 6 As shown, along the winding direction X, the innermost ends of the first extension 411 and the second extension 431 are flush with each other.

[0137] It should be noted that the innermost ends of the first extension 411 and the second extension 431 are flush with each other, but they are not necessarily perfectly flush. Rather, within a certain error range, the innermost ends of the first extension 411 and the second extension 431 are roughly aligned so that the ends of the first extension 411 and the second extension 431 can be cut together.

[0138] Thus, after the winding process of the electrode assembly 32 is completed, the first electrode 41 can be cut together with the innermost diaphragm 43, which helps to simplify the production process of the electrode assembly 32.

[0139] In some embodiments, the first electrode 41 is a negative electrode and the second electrode 42 is a positive electrode.

[0140] During the initial charging of the battery cell 30, lithium ions and other metal ions are released from the positive electrode and embedded in the negative electrode. The first electrode 41 is the negative electrode, and the second electrode 42 is the positive electrode. The innermost edge of the negative electrode extends beyond the innermost edge of the positive electrode. Thus, during the charging of the battery cell 30, the lithium ions and other metal ions released from the positive electrode are always received by the negative electrode, which helps reduce the risk of lithium plating between the electrodes.

[0141] In some embodiments, the insulating tape 50 includes a substrate layer and an adhesive layer. The adhesive layer bonds the substrate layer to the first extension 411 and bonds the substrate layer to the second extension 431. The adhesive layer includes polyethylene adhesive.

[0142] While providing a certain degree of adhesion, polyethylene adhesive also has good ion permeability. Thus, during the cycle operation of the battery cell 30, metal ions such as lithium ions can pass through the insulating tape 50 more smoothly, which is beneficial to improving the dynamic performance of the battery cell 30 and reducing the risk of lithium plating in the electrode assembly 32.

[0143] Secondly, the battery device 10 provided in the embodiments of this application includes the battery cell 30 provided in any of the above embodiments.

[0144] The battery device 10 provided in this application embodiment has the same technical effect as the battery cell 30 provided in any of the above embodiments, and will not be described again here.

[0145] Thirdly, the electrical device provided in the embodiments of this application includes the battery device 10 provided in the above embodiments, and the battery device 10 is used to provide electrical energy.

[0146] The electrical device provided in this application embodiment has the same technical effect as the battery device 10 provided in this application embodiment, and will not be described again here.

[0147] In some embodiments, such as Figures 5 to 8As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, and at least one insulating tape 50. The electrode assembly 32 is housed within the housing 31 and includes a first electrode 41, a second electrode 42, and a separator 43. The first electrode 41 and the second electrode 42 have opposite polarities, and the separator 43 is disposed on both sides of the first electrode 41 and the second electrode 42. The electrode assembly 32 is wound in shape. The first electrode 41 includes a first extension 411, and the innermost separator 43 is located on the second electrode 42, including a second extension 431. Along the winding direction X of the electrode assembly 32, the first extension 411 and the second extension 431 extend beyond the end of the innermost circle of the second electrode 42. At least a portion of the insulating tape 50 is attached to the opposite sides of the first extension 411 and the second extension 431 to limit the relative displacement between at least a portion of the second extension 431 and the first extension 411. Insulating tape 50 covers at least a portion of the ends of the first extension 411 and the second extension 431 along the winding direction X. The insulating tape 50 includes a first part 51, a second part 52, and a connecting part 53. The first part 51 is attached to the side of the first extension 411 opposite to the second extension 431, and the connecting part 53 connects the first part 51 and the second part 52. The first electrode 41 includes a functional region 41a coated with an active material layer and an empty foil region 41b uncoated with an active material layer. The empty foil region 41b is located on the side of the functional region 41a along a first direction Y, which intersects the winding direction X. At least one end of the insulating tape 50 extends beyond the functional region 41a along the first direction Y. Along the first direction Y, the distance h by which the insulating tape 50 extends beyond the functional region 41a satisfies: 1mm ≤ h ≤ 4mm. Along the winding direction X, the innermost ends of the first extension 411 and the second extension 431 are flush with each other. The insulating tape 50 includes a substrate layer and an adhesive layer, the adhesive layer bonding the substrate layer to the first extension 411 and bonding the substrate layer to the second extension 431, the adhesive layer including polyethylene adhesive.

[0148] The battery cell 30 provided in this application embodiment, by attaching at least one insulating tape 50 to the first extension 411 and the second extension 431, restricts the relative displacement between at least a portion of the second extension 431 and the first extension 411, reduces the possibility of the second extension 431 of the innermost separator 43 folding or shifting relative to the first extension 411 of the first electrode 41, thereby reducing the risk of the second extension 431 of the first electrode 41 contacting the second electrode 42 and causing an internal short circuit in the battery cell 30, which is beneficial to improving the reliability of the battery cell 30.

[0149] 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 housed within the housing. The electrode assembly includes a first electrode, a second electrode, and a diaphragm. The first electrode and the second electrode have opposite polarities, and the diaphragm is disposed on both sides of the first electrode and both sides of the second electrode. The electrode assembly is wound in shape, the first electrode includes a first extension, and the innermost diaphragm includes a second extension. Along the winding direction of the electrode assembly, the first extension and the second extension extend beyond the end of the innermost circle of the second electrode. At least one insulating tape is applied at least partially to the opposite sides of the first extension and the second extension to restrict the relative displacement between at least a portion of the second extension and the first extension.

2. The battery cell according to claim 1, characterized in that, The insulating tape covers at least a portion of the ends of the first extension and the second extension along the winding direction.

3. The battery cell according to claim 1, characterized in that, The insulating tape includes a first part, a second part, and a connecting part. The first part is attached to the side of the first extension that is opposite to the second extension. The first part is also attached to the side of the second extension that is opposite to the first extension. The connecting part connects the first part and the second part.

4. The battery cell according to claim 1, characterized in that, At least one of the insulating tapes includes at least two insulating tapes, and the at least two insulating tapes include a first insulating tape and a second insulating tape, wherein the first insulating tape is applied to the side of the first extension away from the second extension, and the second insulating tape is applied to the side of the second extension away from the first extension; The first insulating tape and the second insulating tape are disposed beyond the ends of the first extension and the second extension, and are bonded together.

5. The battery cell according to claim 3 or 4, characterized in that, The insulating tape covers the ends of the first extension and the second extension away from the second electrode along the winding direction; The first electrode includes a functional area coated with an active material layer and an empty foil area not coated with an active material layer. The empty foil area is located on one side of the functional area along a first direction, which intersects with the winding direction. The insulating tape extends beyond the functional area at least at one end along the first direction.

6. The battery cell according to claim 5, characterized in that, Along the first direction, the distance h from the insulating tape beyond the functional area satisfies: 1mm ≤ h ≤ 4mm.

7. The battery cell according to claim 6, characterized in that, 2mm≤h≤3mm.

8. The battery cell according to claim 1, characterized in that, Along the winding direction, the innermost ends of the first extension and the second extension are flush with each other.

9. The battery cell according to claim 1, characterized in that, The first electrode is the negative electrode, and the second electrode is the positive electrode.

10. The battery cell according to claim 1, characterized in that, The insulating tape includes a substrate layer and an adhesive layer. The adhesive layer bonds the substrate layer to the first extension and bonds the substrate layer to the second extension. The adhesive layer includes polyethylene adhesive.

11. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 10.

12. An electrical appliance, characterized in that, Includes the battery device as described in claim 11, the battery device being used to provide electrical energy.

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