Electrode sheet, battery cell, battery, and electrical device

Abstract

The present application provides an electrode sheet, a battery cell, a battery, and an electrical device. The battery cell comprises a first electrode sheet and a second electrode sheet having opposite polarities; the first electrode sheet comprises a first current collecting portion, a first tab portion, a first active material layer, and a first insulating layer; the first tab portion is connected to at least one side of the first current collecting portion; the first active material layer is provided on at least one surface of the first current collecting portion in the thickness direction of the first electrode sheet; the first active material layer comprises two first end surfaces opposite to each other in a first direction; the first direction is parallel to a direction pointing from the first current collecting portion to the first tab portion; and the first insulating layer is at least provided on a surface of the first current collecting portion and is connected to at least one first end surface. The present application can improve the use reliability of the battery cell.

Description

Electrode plates, battery cells, batteries and electrical devices

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese patent application 202410953888.4, filed on July 16, 2024, entitled “Electrode Plates, Battery Cells, Battery and Electrical Devices”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of batteries, specifically to an electrode sheet, a battery cell, a battery, and an electrical device. Background Technology

[0004] Battery cells have characteristics such as high capacity and long lifespan, and are therefore 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.

[0005] As battery applications become more widespread, the requirements for battery performance are becoming increasingly stringent. However, in related technologies, the reliability of individual battery cells during use is relatively poor. Summary of the Invention

[0006] This application is made in view of the above-mentioned problems, and its purpose is to provide an electrode sheet, a battery cell, a battery, and an electrical device that can improve the reliability of the battery cell.

[0007] In a first aspect, embodiments of this application propose a battery cell, which includes a first electrode and a second electrode with opposite polarities. The first electrode includes a first current collector, a first tab, a first active material layer, and a first insulating layer. The first tab is connected to at least one side of the first current collector. The first active material layer is disposed on at least one surface of the first current collector along the thickness direction of the first electrode. The first active material layer includes two first end faces that are opposite to each other along a first direction, which is parallel to the direction from the first current collector to the first tab. The first insulating layer is disposed on at least one surface of the first current collector and is connected to at least one first end face.

[0008] Therefore, by providing a first insulating layer on the first end face of the first active material layer, the present application embodiment can reduce the risk of short circuit between the first electrode and the second electrode and improve the reliability of the battery cell.

[0009] In some embodiments, the surface of the first insulating layer facing away from the first current collector is flush with the surface of the first active material layer facing away from the first current collector. When the surfaces are flush, uniform stress is applied to the second electrode, which can improve the lithium deposition morphology.

[0010] In some embodiments, the first active material layer includes a first film layer and a second film layer. The first film layer is disposed on at least one surface of the first current collector along the thickness direction and includes two first surfaces facing each other along a first direction. The second film layer is disposed on the surface of the first film layer away from the first current collector and includes two second surfaces facing each other along the first direction. The first end face includes a first surface and a second surface, and both the first surface and the second surface are connected to the first insulating layer.

[0011] Therefore, in the embodiments of this application, the first insulating layer can protect the end faces of the first film layer and the second film layer, reduce the risk of lithium powder drifting to the edge of the first active material layer and causing self-discharge and heat generation, and improve the reliability of the battery cell.

[0012] In some embodiments, the first film layer extends beyond the second film layer along a first direction. The relatively long dimension of the first film layer along the first direction can further increase the capacity of the first electrode, thereby increasing the energy density of the battery cell; moreover, it is beneficial for the stepped structure of the first insulating layer to cover the edge of the first active material layer, which can increase the connection area between the first insulating layer and the first active material layer and improve the stability of their bonding.

[0013] In some embodiments, the first insulating layer includes a first insulating portion and a second insulating portion. The first insulating portion is disposed on the surface of the first current collector and connected to the first surface. The second insulating portion is disposed on the surface of the first insulating portion away from the first current collector and connected to the second surface. The second insulating portion extends beyond the first surface in a first direction.

[0014] Therefore, the above-mentioned arrangement in the embodiments of this application enables the second insulating part to further insulate and protect the first film layer, for example, the exposed surface of the first film layer away from the first current collector, thereby further reducing the risk of self-discharge and heat generation when lithium powder and the first active material layer come into contact.

[0015] In some embodiments, the surface of the second insulating portion facing away from the second film layer is flush with the surface of the first insulating portion facing away from the first film layer. In this case, the second insulating portion can increase the protective effect on the first film layer, and the first insulating layer and the first active material layer are basically of equal thickness, which can apply more uniform pressure to the second electrode, resulting in a better lithium deposition morphology in the second electrode, making it less prone to lithium dendrite formation, and further improving the reliability of the battery cell.

[0016] In some embodiments, the dimension of the first insulating portion along the first direction is from 0.5 mm to 15 mm. When the dimension of the first insulating portion along the first direction is within the above range, it can effectively provide insulation and protection for the edge of the first film layer.

[0017] In some embodiments, the dimension of the second insulating portion along the first direction is 0.2 mm to 3 mm. When the dimension of the second insulating portion along the first direction is within the above range, it can effectively provide insulation protection for the edge of the second film layer.

[0018] In some embodiments, the main material of the first insulating layer includes at least one of inorganic and organic insulating materials. Inorganic particles can provide insulation and heat resistance, improving the insulation and heat resistance of the edges of the first active material layer. Organic insulating materials have a stronger bond with the first active material layer, providing excellent insulation and protection for the first active material layer.

[0019] In some embodiments, the inorganic insulating material includes inorganic particles, which include one or more of boehmite, alumina, aluminum hydroxide, barium sulfate, magnesium oxide, magnesium hydroxide, calcium oxide, cerium oxide, zirconium titanate, barium titanate, and magnesium fluoride.

[0020] In some embodiments, the organic insulating material includes one or more of polyolefins, epoxy resins, polyacrylic acid, and styrene-butadiene rubber.

[0021] In some embodiments, the second electrode includes a second current collector and a second active material layer. The second active material layer is disposed on at least one surface of the second current collector along its thickness direction, and the second active material layer and the first active material layer are disposed opposite each other along their thickness directions. Active ions migrate between the second active material layer and the first active material layer, enabling the cyclic charging and discharging of the battery cell.

[0022] In some embodiments, the first electrode is a positive electrode and the second electrode is a negative electrode; along the thickness direction, the projection surface of the second active material layer partially overlaps with the projection surface of the first insulating layer.

[0023] Therefore, in this embodiment, the first insulating layer is located at the edge of the first active material layer along the first direction, and the projection surface of the second active material layer partially overlaps with the projection surface of the first insulating layer. This means that the area where lithium ions are released from the first active material layer is smaller than the area where lithium ions are received by the second active material layer, so that the lithium ions released from the first active material layer can be basically received by the second active material layer, reducing the risk of lithium plating on the second electrode.

[0024] In some embodiments, the second active material layer includes a third film layer and a fourth film layer. The third film layer is disposed on at least one surface of the second current collector along the thickness direction; the fourth film layer is disposed on the surface of the third film layer opposite to the second current collector, wherein the third film layer extends beyond the fourth film layer along a first direction. This is beneficial for increasing the capacity of the negative electrode sheet, thereby increasing the energy density of the battery cell.

[0025] In some embodiments, the projection surface of the third film layer partially overlaps with the projection surface of the first insulating layer along the thickness direction.

[0026] Therefore, in the embodiments of this application, the area of ​​the third film layer that receives lithium ions is larger than the area of ​​the first active material layer that releases lithium ions, thereby reducing the risk of lithium deposition on the third film layer in the second electrode.

[0027] In some embodiments, the projection surface of the fourth film layer partially overlaps with the projection surface of the first insulating layer along the thickness direction; this can further increase the area of ​​the second active material layer that receives lithium ions and reduce the risk of lithium plating on the second electrode.

[0028] In some embodiments, the third film layer includes a film layer body and a film layer extension, the film layer body and the fourth film layer being disposed opposite each other along the thickness direction; the film layer extension is connected to at least one side of the film layer body along a first direction and extends beyond the fourth film layer, wherein the first insulating layer extends beyond the film layer extension along the first direction.

[0029] Therefore, in the embodiments of this application, the first insulating layer can cover foreign objects such as burrs on the second electrode, further reducing the risk of short circuit between the positive and negative electrodes and improving the reliability of the battery cell.

[0030] In some embodiments, the dimension of the film extension along the first direction is 0.2 mm to 5 mm. When the dimension of the film extension along the first direction is within the above range, the area of ​​the second active material layer that receives lithium ions can be increased, reducing the risk of lithium plating on the second electrode.

[0031] In some embodiments, the second active material layer includes two second end faces that are opposite to each other along a first direction; the second electrode also includes a second insulating layer, which is disposed at least on the surface of the second current collector and connected to at least one second end face.

[0032] Therefore, by providing a second insulating layer on the second end face of the second active material layer, the present application embodiment can reduce the risk of short circuit between the first electrode and the second electrode, thereby improving the reliability of the battery cell.

[0033] Secondly, this application proposes an electrode sheet, which includes a first current collector, a first tab, a first active material layer, and a first insulating layer. The first tab is connected to at least one side of the first current collector. The first active material layer is disposed on at least one surface of the first current collector along the thickness direction of the first electrode sheet. The first active material layer includes two first end faces that are opposite each other along a first direction, which is parallel to the direction from the first current collector to the first tab. The first insulating layer is disposed on at least one surface of the first current collector and is connected to at least one first end face.

[0034] Therefore, by providing a first insulating layer on the first end face of the first active material layer, the present application embodiment can reduce the risk of short circuit between the first electrode and the second electrode and improve the reliability of the battery cell.

[0035] In some embodiments, the surface of the first insulating layer facing away from the first current collector is flush with the surface of the first active material layer facing away from the first current collector. When the surfaces are flush, uniform stress is applied to the second electrode, which can improve the lithium deposition morphology.

[0036] In some embodiments, the first active material layer includes a first film layer and a second film layer. The first film layer is disposed on at least one surface of the first current collector along the thickness direction and includes two first surfaces facing each other along a first direction. The second film layer is disposed on the surface of the first film layer away from the first current collector and includes two second surfaces facing each other along the first direction. The first end face includes a first surface and a second surface, and both the first surface and the second surface are connected to the first insulating layer.

[0037] Therefore, in the embodiments of this application, the first insulating layer can protect the end faces of the first film layer and the second film layer, reduce the risk of lithium powder drifting to the edge of the first active material layer and causing self-discharge and heat generation, and improve the reliability of the battery cell.

[0038] In some embodiments, the first film layer extends beyond the second film layer along a first direction. The relatively long dimension of the first film layer along the first direction can further increase the capacity of the first electrode, thereby increasing the energy density of the battery cell; moreover, it is beneficial for the stepped structure of the first insulating layer to cover the edge of the first active material layer, which can increase the connection area between the first insulating layer and the first active material layer and improve the stability of their bonding.

[0039] In some embodiments, the first insulating layer includes a first insulating portion and a second insulating portion. The first insulating portion is disposed on the surface of the first current collector and connected to the first surface. The second insulating portion is disposed on the surface of the first insulating portion away from the first current collector and connected to the second surface. The second insulating portion extends beyond the first surface in a first direction.

[0040] Therefore, the above-mentioned arrangement in the embodiments of this application enables the second insulating part to further insulate and protect the first film layer, for example, the exposed surface of the first film layer away from the first current collector, thereby further reducing the risk of self-discharge and heat generation when lithium powder and the first active material layer come into contact.

[0041] In some embodiments, the surface of the second insulating portion facing away from the second film layer is flush with the surface of the first insulating portion facing away from the first film layer. In this case, the second insulating portion can increase the protective effect on the first film layer, and the first insulating layer and the first active material layer are basically of equal thickness, which can apply more uniform pressure to the second electrode, resulting in a better lithium deposition morphology in the second electrode, making it less prone to lithium dendrite formation, and further improving the reliability of the battery cell.

[0042] In some embodiments, the dimension of the first insulating portion along the first direction is from 0.5 mm to 15 mm. When the dimension of the first insulating portion along the first direction is within the above range, it can effectively provide insulation and protection for the edge of the first film layer.

[0043] In some embodiments, the dimension of the second insulating portion along the first direction is 0.2 mm to 3 mm. When the dimension of the second insulating portion along the first direction is within the above range, it can effectively provide insulation protection for the edge of the second film layer.

[0044] Thirdly, this application proposes a battery comprising a battery cell as described in any embodiment of the first aspect of this application.

[0045] Fourthly, this application proposes an electrical device comprising a battery cell as described in the third aspect of this application. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0047] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0048] Figure 2 is a schematic diagram of the explosion of a battery provided in some embodiments of this application;

[0049] Figure 3 is a schematic diagram of the structure of a battery module provided in some embodiments of this application.

[0050] Figure 4 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0051] Figure 5 is an exploded schematic diagram of a battery cell provided in some embodiments of this application;

[0052] Figure 6 is a schematic diagram of the structure of the electrode assembly of a battery cell provided in some embodiments of this application;

[0053] Figure 7 is a schematic diagram of the structure of the first electrode of a battery cell provided in some embodiments of this application;

[0054] Figure 8 is a schematic diagram of the structure of the second electrode of a battery cell provided in some embodiments of this application.

[0055] The accompanying drawings may not be drawn to scale.

[0056] The reference numerals in the attached drawings are explained as follows: X, thickness direction; Y, first direction; 1, vehicle; 2, battery; 3, controller; 4, motor; 5, housing; 5a, first housing section; 5b, second housing section; 5c, accommodating space; 6, battery module; 7, battery cell; 10, electrode assembly; 12, main body section; 20, outer shell; 21, casing; 22, end cap; 40, first electrode; 41, first current collector; 42, first tab; 43, first active material layer; 430, first end face; 431, first film layer; 4310, first surface; 432, second film layer; 4320, second surface; 44, first insulating layer; 441, first insulating part; 442, second insulating part; 50, second electrode; 51, second current collector; 52, second tab; 53, second active material layer; 530, second end face; 531, Third membrane layer; 5310, Third surface; 5311, Membrane body; 5312, Membrane extension; 532, Fourth membrane layer; 5320, Fourth surface; 54, Second insulating layer; 60, Separating membrane. Detailed Implementation

[0057] The following detailed description discloses embodiments of the electrode plates, battery cells, batteries, and power-consuming devices of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0058] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0059] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0060] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0061] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0062] In this application, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations.

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

[0064] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: 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.

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

[0066] In this application, "multiple" refers to two or more (including two). In the embodiments of this application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used.

[0067] In this application, the battery cell may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium lithium-ion battery cells, sodium-ion battery cells, magnesium-ion battery cells, lithium metal battery cells, sodium metal batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited to these shapes either. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these types either.

[0068] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a casing for encapsulating one or more battery cells. The casing can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0069] A battery cell consists of electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of active ions, such as lithium ions, between the positive and negative electrodes. There is a risk of short circuits occurring between the positive and negative electrodes, which degrades the reliability of the battery cell.

[0070] In view of this, the embodiments of this application improve the electrode sheet by providing an insulating layer on the end face of the active material layer in the electrode sheet, thereby reducing the risk of short circuit between the positive and negative electrodes.

[0071] The battery cells described in this application are applicable to batteries and electrical devices that use batteries.

[0072] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of this application do not impose special limitations on the above-mentioned electrical devices.

[0073] For ease of explanation, the following implementation method uses a vehicle as an example of an electrical device.

[0074] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application.

[0075] As shown in Figure 1, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0076] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0077] In some embodiments of this application, the battery 2 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.

[0078] Figure 2 is an exploded view of a battery provided in some embodiments of this application. As shown in Figure 2, the battery 2 includes a housing 5 and a battery cell (not shown in Figure 2), with the battery cell housed within the housing 5.

[0079] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one open end, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one open side, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0080] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0081] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0082] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0083] A single battery cell can be the smallest unit that makes up a battery.

[0084] Figure 3 is a schematic diagram of the battery module shown in Figure 2.

[0085] In some embodiments, as shown in Figure 3, there are multiple battery cells 7. These multiple battery cells 7 are first connected in series, parallel, or in a mixed manner to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or in a mixed manner to form a whole, which is housed in a casing.

[0086] Multiple battery cells 7 in battery module 6 can be electrically connected through busbars to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module. There can be one or more busbars, each used to electrically connect at least two battery cells 7.

[0087] Figure 4 is a structural schematic diagram of the battery cell 7 provided in some embodiments of this application; Figure 5 is an exploded schematic diagram of the battery cell 7 shown in Figure 4.

[0088] As shown in Figures 4 and 5, in some embodiments, the battery cell 7 includes an electrode assembly 10 and a housing 20, with the electrode assembly 10 housed within the housing 20.

[0089] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.

[0090] The housing 21 is a component used to cooperate with the end cap 22 to form the internal cavity of the battery cell 7. The formed internal cavity can accommodate the electrode assembly 10, the electrolyte, and other components. The housing 21 can have various shapes, such as a cylinder or a cuboid. The shape of the housing 21 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, the housing 21 can be a cylindrical structure. If the electrode assembly 10 has a cuboid structure, the housing 21 can be a cuboid structure.

[0091] The shell 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc. The embodiments of this application do not impose any special restrictions on this.

[0092] The electrode assembly 10 housed within the housing 21 may be one or more.

[0093] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the battery cell 7.

[0094] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0095] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0096] From the external shape of the electrode assembly 10, the electrode assembly 10 includes a main body 12, a first electrode tab 42, and a second electrode tab 52. The first electrode tab 42 and the second electrode tab 52 have opposite polarities and extend beyond the main body 12. The first electrode tab 42 is the portion of the first electrode sheet that is not coated with an active material layer, and the second electrode tab 52 is the portion of the second electrode sheet that is not coated with an active material layer. The first electrode tab 42 and the second electrode tab 52 are used to draw current from the main body 12. The first electrode sheet and the second electrode sheet have opposite polarities; in other words, one of the first electrode sheet and the second electrode sheet is a positive electrode sheet, and the other of the first electrode sheet and the second electrode sheet is a negative electrode sheet.

[0097] Taking the first electrode tab 42 as the positive electrode tab and the second electrode tab 52 as the negative electrode tab as an example, the portion of the negative electrode current collector in the negative electrode sheet that is not coated with an active material layer is the negative electrode tab. The active material coated on the negative electrode current collector in the negative electrode sheet constitutes the negative electrode film layer. The negative electrode film layer and the portion of the negative electrode current collector coated with active material are part of the main body 12. Similarly, the portion of the positive electrode current collector in the positive electrode sheet that is not coated with an active material layer is the positive electrode tab. The active material coated on the positive electrode current collector in the positive electrode sheet constitutes the positive electrode film layer. The positive electrode film layer and the portion of the positive electrode current collector coated with active material are part of the main body 12.

[0098] The positive electrode tab and the negative electrode tab can be drawn from the same end of the main body 12, or the positive electrode tab and the negative electrode tab can be drawn from opposite ends of the main body 12.

[0099] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 7, active ions (e.g., lithium ions) repeatedly insert and extract between the positive and negative electrodes. Optionally, the electrode assembly 10 also includes a separator disposed between the positive and negative electrodes, which can reduce the risk of short circuit between the positive and negative electrodes while allowing active ions to pass through.

[0100] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0101] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0102] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, silver-surfaced aluminum, or stainless steel can be used. 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.).

[0103] As an example, when the battery cell 7 in this embodiment is a lithium-ion battery or a lithium metal battery, the positive electrode active material may include at least one of the following materials: phosphate, layered transition metal oxide, and their respective modified compounds; optionally, the positive electrode active material may include layered transition metal oxide and their respective modified compounds, which is beneficial to improving the energy density of the battery cell 7. However, this application is not limited to these materials, and other conventional materials that can be used as the positive electrode film layer of a battery may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0104] Examples of phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0105] Layered transition metal oxides include those with the general formula Li a Ni b Co c M d O e A f At least one of the compounds and their modified compounds. 0.8≤a≤1.2, 0.3≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes at least one of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes at least one of N, F, S and Cl.

[0106] Examples of layered transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0107] When the battery cell 7 in the embodiments of this application is a sodium-ion battery or a sodium metal battery, the positive electrode active material may include, but is not limited to, at least one of sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials.

[0108] As an example, positive electrode active materials for sodium-ion batteries may include NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x At least one of the materials in general formula X. p M' q (PO4) r O x Y 3-x In the given condition, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes H. + Li + Na + K+ and NH4 + At least one of the following, M' is a transition metal cation, optionally at least one of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally at least one of F, Cl and Br.

[0109] In the embodiments of this application, the modified compounds of the above-mentioned positive electrode active materials can be doped and / or surface coated to modify the positive electrode active materials, such as carbon coating modification, fast ion conductor coating modification, etc.

[0110] During the charging and discharging process, the battery cell 7 undergoes the insertion and extraction of active ions such as Li, resulting in a different molar content of Li in the battery cell 7 at different discharge states. In the examples of positive electrode active materials in this application, the molar content of Li refers to the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to the battery system, the molar content of Li may change after charge-discharge cycles.

[0111] In the embodiments of this application, the molar content of oxygen (O) in the positive electrode active materials is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of oxygen (O) to change. In reality, the molar content of oxygen (O) will fluctuate.

[0112] In this embodiment, the elemental content in the positive electrode active material is defined in a way known in the art and can be detected using equipment and methods known in the art. For example, referring to EPA6010D-2014, it can be measured by inductively coupled plasma atomic emission spectrometry (ICP-OES, instrument model: Thermo ICAP7400). First, 0.4g of the positive electrode active material is weighed and 10ml (50wt%) of aqua regia is added. Then, it is placed on a plate at 180℃ for 30min. After digestion on the plate, the volume is adjusted to 100mL, and quantitative testing is performed using the standard curve method.

[0113] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, a positive electrode film layer may or may not be provided on the surface of the foamed metal. As an example, lithium source material, potassium metal, or sodium metal may also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0114] In some embodiments, the positive electrode film layer may optionally include a positive electrode conductive agent. This application does not impose particular limitations on the type of positive electrode conductive agent. As an example, the positive electrode conductive agent includes at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode film layer is ≤5 wt%.

[0115] In some embodiments, the positive electrode film layer may optionally include a positive electrode binder. This application does not impose particular limitations on the type of positive electrode binder. As an example, the positive electrode binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode film layer is ≤5 wt%.

[0116] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, optional conductive agent, optional binder, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to it.

[0117] In some embodiments, the battery cell is an ion-type battery such as a lithium-ion battery, and the negative electrode can be a negative electrode sheet. The negative electrode sheet can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector. The negative electrode film layer includes a negative electrode active material.

[0118] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0119] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper 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.).

[0120] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cell 7. As an example, the negative electrode active material may include at least one of the following materials: carbon materials (e.g., carbon materials include at least one of artificial graphite, natural graphite, soft carbon, and hard carbon), silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may include at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include 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 battery negative electrode films may also be used. These negative electrode films may be used alone or in combination of two or more.

[0121] In some embodiments, the negative electrode film layer may optionally include a negative electrode conductive agent. This application does not impose particular limitations on the type of negative electrode conductive agent. As an example, the negative electrode conductive agent may include at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon fibers. In some embodiments, the mass percentage of the negative electrode conductive agent in the negative electrode film layer is ≤5 wt%.

[0122] In some embodiments, the negative electrode film layer may optionally include a negative electrode binder. This application does not impose particular limitations on the type of negative electrode binder. As an example, the negative electrode binder may include at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage of the negative electrode binder in the negative electrode film layer is ≤5 wt%.

[0123] In some embodiments, the negative electrode film layer may optionally include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of other additives in the negative electrode film layer is ≤2 wt%.

[0124] In other embodiments, when the battery cell is a metal-type battery such as a lithium metal battery or a sodium metal battery, the negative electrode sheet may include a negative current collector but not a negative active material. Taking a lithium metal battery as an example, during the charging process of a lithium metal battery, lithium ions can be deposited on the surface of the negative current collector to form a lithium metal layer; during the discharging process of a lithium metal battery, the lithium metal layer loses electrons to form lithium ions, which migrate to the positive active material.

[0125] Optionally, the negative electrode may also include a lithium metal layer disposed on at least one surface of the negative electrode current collector.

[0126] Optionally, the negative electrode sheet may further include an active layer (e.g., composed of a conductive agent and a binder) disposed on the surface of the negative electrode current collector. For example, the conductive agent may include at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon fibers. For example, the binder may include at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0127] In some embodiments, the battery cell 7 further includes a separator, which includes 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.

[0128] The embodiments of this application do not have any particular restrictions on the type of separator membrane, and any known porous structure separator membrane with good chemical and mechanical stability can be selected.

[0129] In some embodiments, the material of the separator may include one or more of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may 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 may be the same or different, without particular limitation.

[0130] In some embodiments, the separator may include a porous base membrane and a coating disposed on at least one side of the porous base membrane, the coating including at least one of inorganic particles or organic particles.

[0131] Porous base membranes may include one or more of polyethylene and polypropylene.

[0132] Inorganic particles possess good heat resistance, which can improve the overall heat resistance of the separator. Within the operating voltage range of sodium-ion batteries, inorganic particles essentially do not undergo oxidation and reduction reactions with metal dendrites. In other words, inorganic particles are configured to prevent oxidation and reduction reactions with alkali metals and / or alkaline earth metals at the nominal voltage of sodium-ion batteries.

[0133] In some embodiments, the inorganic particles include one or more of boehmite γ-AlOOH, aluminum oxide Al2O3, aluminum hydroxide Al(OH)3, barium sulfate BaSO4, magnesium oxide MgO, magnesium hydroxide Mg(OH)2, calcium oxide CaO, cerium oxide CeO2, zirconium titanate SrTiO3, barium titanate BaTiO3, and magnesium fluoride MgF2.

[0134] In some embodiments, the organic particles include at least one of polystyrene, polyethylene, polyimide, melamine resin, phenolic resin, polypropylene, polyester (e.g., polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate), polyphenylene sulfide, polyarylamide, polyamide-imide, polyimide, copolymers of butyl acrylate and ethyl methacrylate, and mixtures thereof.

[0135] In some implementations, the battery cell also includes an electrolyte.

[0136] During the charging and discharging process of a single battery cell, active ions repeatedly insert and extract between the positive and negative electrode plates, while the electrolyte acts as a conductor for these active ions. The embodiments of this application do not impose any particular restrictions on the type of electrolyte; it can be selected according to actual needs.

[0137] Electrolytes consist of electrolyte salts and solvents. The types of electrolyte salts and solvents are not specifically limited and can be selected according to actual needs.

[0138] When the battery cell in the embodiments of this application is a lithium-ion battery or a lithium metal battery, as an example, the electrolyte salt may include, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0139] When the battery cell in the embodiments of this application is a sodium-ion battery or a sodium metal battery, as an example, the electrolyte salt may include, but is not limited to, at least one of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0140] As an example, the solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0141] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature power performance.

[0142] As shown in Figures 4 to 8, in some embodiments, the electrode assembly 10 can be a wound structure or a stacked structure. Taking the stacked structure as an example, multiple positive and negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and multiple negative electrode sheets are alternately stacked to form the electrode assembly 10 through a stacking process. Figure 6 shows the stacked electrode assembly.

[0143] In some embodiments, the battery cell 7 includes a first electrode 40 and a second electrode 50 with opposite polarities. The first electrode 40 includes a first current collector 41, a first tab 42, a first active material layer 43, and a first insulating layer 44. The first tab 42 is connected to at least one side of the first current collector 41. The first active material layer 43 is disposed on at least one surface of the first current collector 41 along the thickness direction X of the first electrode 40. The first active material layer 43 includes two first end faces 430 facing each other along a first direction Y, which is parallel to the direction from the first current collector 41 to the first tab 42. The first insulating layer 44 is disposed at least on the surface of the first current collector 41 and is connected to at least one first end face 430. Optionally, the battery cell 7 further includes a separator 60 disposed between the first electrode 40 and the second electrode 50.

[0144] The first electrode 40 and the second electrode 50 are both electrode plates in the battery cell 7. The first electrode 40 and the second electrode 50 have opposite polarities. In other words, one of the first electrode 40 and the second electrode 50 is the positive electrode plate, and the other of the first electrode 40 and the second electrode 50 is the negative electrode plate.

[0145] A first active material layer 43 is disposed on the first current collector 41, while the first electrode tab 42 does not have the first active material layer 43 disposed on it. The first electrode tab 42 is used to draw out the current from the first active material layer 43. The first electrode tab 42 can be disposed on one side or both sides of the first current collector 41. The direction from the first current collector 41 to the first electrode tab 42 is parallel to the first direction Y, which is perpendicular to the thickness direction X of the first electrode 40.

[0146] The first active material layer 43 is disposed on at least one surface of the first current collector 41, for example, it can be disposed on one or both surfaces of the first current collector 41. The first active material layer 43 can partially cover the first current collector 41, providing space for the placement of the first insulating layer 44. By using the first insulating layer 44 to cover the first end face 430 of the first active material layer 43, the risk of short circuit between this location and the second electrode 50 can be reduced.

[0147] The first insulating layer 44 can be disposed on either of the two first end faces 430, or on both first end faces 430. When disposed on both first end faces 430, it can improve the protective effect on the first active material layer 43 and improve the reliability of the battery cell 7. Since the first insulating layer 44 is connected to the first end face 430, the first insulating layer 44 is disposed at least on the surface of the first current collector 41. Of course, the first insulating layer 44 can also be further disposed in the connection area between the first current collector 41 and the first tab 42, or even in a part of the first tab 42 near the first current collector 41, thereby increasing the connection stability between the first current collector 41 and the first tab 42 and further improving the reliability of the battery cell 7.

[0148] Therefore, by providing a first insulating layer 44 on the first end face 430 of the first active material layer 43, the present invention can reduce the risk of short circuit between the first electrode 40 and the second electrode 50 and improve the reliability of the battery cell 7.

[0149] In some embodiments, the second electrode 50 includes a second current collector 51 and a second active material layer 53. The second active material layer 53 is disposed on at least one surface of the second current collector 51 along the thickness direction X, and the second active material layer 53 and the first active material layer 43 are disposed opposite each other along the thickness direction X. Active ions migrate between the first active material layer 43 and the second active material layer 53, realizing the cyclic charging and discharging of the battery cell 7. Optionally, the second electrode 50 further includes a second tab 52, which is connected to at least one side of the second current collector 51.

[0150] Optionally, the second electrode 50 may further include a second insulating layer 54, and the second active material layer 53 includes two second end faces 530 facing each other along the first direction Y. The second insulating layer 54 is at least disposed on the surface of the second current collector 51 and connected to at least one second end face 530. Of course, the second electrode 50 may also omit the second insulating layer 54.

[0151] The second insulating layer 54 can be disposed on either of the two second end faces 530, or on both second end faces 530. When disposed on both second end faces 530, it can improve the protective effect on the second active material layer 53 and improve the reliability of the battery cell 7. Since the second insulating layer 54 is connected to the second end face 530, the second insulating layer 54 is disposed at least on the surface of the second current collector 51. Of course, the second insulating layer 54 can also be further disposed in the connection area between the second current collector 51 and the second tab 52, or even in a portion of the second tab 52 near the second current collector 51, thereby increasing the connection stability between the second current collector 51 and the second tab 52 and further improving the reliability of the battery cell 7.

[0152] Therefore, by providing a second insulating layer 54 on the second end face 530 of the second active material layer 53, the risk of short circuit between the first electrode 40 and the second electrode 50 can be reduced through the second insulating layer 54, thereby improving the reliability of the battery cell 7.

[0153] When the first electrode 40 is a positive electrode and the second electrode 50 is a negative electrode, the positive electrode may include a first insulating layer 44 and the negative electrode may not include a second insulating layer 54; or the positive electrode may include a first insulating layer 44 and the negative electrode may include a second insulating layer 54.

[0154] When the first electrode 40 is a negative electrode and the second electrode 50 is a positive electrode, the negative electrode may include a first insulating layer 44, and the positive electrode may not include a second insulating layer 54; or the negative electrode may include a first insulating layer 44, and the positive electrode may include a second insulating layer 54.

[0155] The following explanation will take the first electrode 40 as the positive electrode and the second electrode 50 as the negative electrode as an example.

[0156] Generally, to reduce the risk of lithium plating on the negative electrode, the size of the lithium-ion receiving region in the negative electrode is larger than the size of the lithium-ion providing region in the positive electrode. However, this setting will result in the region of the negative electrode that extends beyond the positive electrode being in a stress-free state in the area where lithium ions gain electrons (e.g., the lithium deposition region). This leads to poor lithium deposition morphology and a tendency to produce highly porous dead lithium or dendritic lithium, causing lithium powder to accumulate during cycling. This portion of lithium powder may be released to the positive electrode side through the electrolyte, causing abnormal capacity or short circuits, leading to thermal melting of the separator or even thermal runaway of the battery cell, thus deteriorating the reliability of the battery cell.

[0157] As shown in Figures 4 to 8, in this embodiment of the application, the first insulating layer 44 is connected to the first end face 430 of the first active material layer 43. The first insulating layer 44 can form uniform stress on the second electrode 50, improve the lithium deposition morphology on the second electrode 50, especially the lithium deposition morphology at the end of the second electrode 50, reduce the risk of lithium dendrite formation, and reduce the risk of lithium powder accumulation and deterioration. The first insulating layer 44 can also provide large-area and effective protection for the end of the first active material layer 43, increase the creep distance of lithium powder or solid electrolyte interphase (SEI) film drifting to the first active material layer 43, reduce the self-discharge heat accumulation caused by lithium powder contacting the first active material layer 43, and improve the reliability of the battery cell 7.

[0158] In some embodiments, the surface of the first insulating layer 44 facing away from the first current collector 41 is flush with the surface of the first active material layer 43 facing away from the first current collector 41. This surface is parallel to the first direction Y and perpendicular to the thickness direction X of the electrode. When the surfaces are flush, uniform stress is applied to the second electrode 50, which can improve the lithium deposition morphology. In Figure 7, S1 represents the surface of the first insulating layer 44 facing away from the first current collector 41, and S2 represents the surface of the first active material layer 43 facing away from the first current collector 41.

[0159] Of course, the surface of the first insulating layer 44 facing away from the first current collector 41 may not be flush with the surface of the first active material layer 43 facing away from the first current collector 41. For example, the surface of the first insulating layer 44 facing away from the first current collector 41 may extend beyond the surface of the first active material layer 43 facing away from the first current collector 41 along the thickness direction X. This arrangement can further reduce the risk of lithium powder drift at the end of the negative electrode and self-discharge heat generation between the positive electrode surface and the positive electrode. Alternatively, the surface of the first active material layer 43 facing away from the first current collector 41 may extend beyond the surface of the first insulating layer 44 facing away from the first current collector 41.

[0160] In this embodiment, the first active material layer 43 can be a single-layer film or a multi-layer film. When the first active material layer 43 is a multi-layer film, it can be two or more layers, such as two, three, four, etc. Taking a two-layer first active material layer 43 as an example: the first active material layer 43 includes a first film layer 431 and a second film layer 432. The first film layer 431 is disposed on at least one surface of the first current collector 41 along the thickness direction X. The second film layer 432 is disposed on the surface of the first film layer 431 away from the first current collector 41. The first film layer 431 includes two first surfaces 4310 that are opposite to each other along the first direction Y. The second film layer 432 includes two second surfaces 4320 that are opposite to each other along the first direction Y. The first end face 430 includes the first surface 4310 and the second surface 4320. Both the first surface 4310 and the second surface 4320 are connected to the first insulating layer 44.

[0161] The double-layer coating can increase the coating weight of the first electrode 40, thereby increasing the energy density of the battery cell 7; the first insulating layer 44 can protect the end faces of the first film layer 431 and the second film layer 432, reduce the risk of lithium powder drifting to the edge of the first active material layer 43 and causing self-discharge and heat generation, and improve the reliability of the battery cell 7.

[0162] Optionally, the thickness of the first film layer 431 is greater than the thickness of the second film layer 432. The relatively thicker thickness of the first film layer 431 can effectively increase the capacity of the first electrode 40, thereby increasing the energy density of the battery cell 7.

[0163] For example, the thickness of the first film layer 431 is from 10 μm to 100 μm, such as 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm or any range of two of the above values.

[0164] For example, the thickness of the second film layer 432 is from 10 μm to 80 μm, such as 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm or any range of two of the above values.

[0165] The positive electrode active materials in the first film layer 431 and the second film layer 432 can be at least one of the phosphates, layered transition metal oxides and their respective modified compounds described above, and will not be repeated here. The types and contents of the positive electrode conductive agent and the positive electrode binder in the first film layer 431 and the second film layer 432 can be the schemes described above, and will not be repeated here.

[0166] The dimensions of the first film layer 431 and the second film layer 432 in the first direction Y can be equal or unequal. Optionally, the first film layer 431 extends beyond the second film layer 432 along the first direction Y; in other words, a portion of the first film layer 431 protrudes beyond the second film layer 432 along the first direction Y. In this case, the dimensions of the first film layer 431 and the second film layer 432 are unequal. Optionally, the dimension of the first film layer 431 along the first direction Y is greater than the dimension of the second film layer 432 along the first direction Y. The first film layer 431 may extend beyond at least one side of the second film layer 432 along the first direction Y, such as either side or both sides. The relatively long dimension of the first film layer 431 along the first direction Y can further increase the capacity of the first electrode 40, thereby increasing the energy density of the battery cell 7. Moreover, it is beneficial for the stepped structure of the first insulating layer 44 to cover the edge of the first active material layer 43, which can increase the connection area between the first insulating layer 44 and the first active material layer 43 and improve the stability of their bonding.

[0167] In some embodiments, the first insulating layer 44 includes a first insulating portion 441 and a second insulating portion 442. The first insulating portion 441 is disposed on the surface of the first current collector 41 and connected to the first surface 4310; the second insulating portion 442 is disposed on the surface of the first insulating portion 441 opposite to the first current collector 41 and connected to the second surface 4320. The first insulating portion 441 and the second insulating portion 442 may be made of the same or similar materials, and there may be no clear boundary between them; or the first insulating portion 441 and the second insulating portion 442 may be made of different materials, and there may be a boundary between them.

[0168] The first insulating part 441 protects the edge of the first film layer 431, i.e., the first surface 4310, and the second insulating part 442 protects the edge of the second film layer 432, i.e., the second surface 4320, which can reduce the risk of self-discharge and heat generation caused by contact between lithium powder and the first active material layer 43.

[0169] Optionally, the second insulating portion 442 extends beyond the first surface 4310 along the first direction Y. This arrangement causes a portion of the second insulating portion 442 to protrude from the first insulating portion 441 along the first direction Y. The second insulating portion 442 can further provide insulation protection for the first film layer 431, for example, protecting the exposed surface of the first film layer 431 away from the first current collector 41, further reducing the risk of self-discharge and heat generation due to contact between lithium powder and the first active material layer 43. Of course, the surface of the second insulating portion 442 can also be flush with the first surface 4310.

[0170] Along the first direction Y, when the second insulating portion 442 extends beyond the first surface 4310, the first insulating portion 441 may extend beyond the second insulating portion 442, or the surfaces of the first insulating portion 441 and the second insulating portion 442 may be flush. Specifically, the surface of the second insulating portion 442 facing away from the second film layer 432 is flush with the surface of the first insulating portion 441 facing away from the first film layer 431. In this case, the second insulating portion 442 can increase the protective effect on the first film layer 431, and the first insulating layer 44 and the first active material layer 43 are basically of equal thickness, which can apply more uniform pressure to the second electrode 50, resulting in a better lithium deposition morphology in the second electrode 50, making it less prone to lithium dendrite formation, and further improving the reliability of the battery cell 7.

[0171] For example, the dimension of the first insulating portion 441 along the first direction Y is from 0.5 mm to 15 mm, such as 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, 15 mm, or any combination of two of the above values. When the dimension of the first insulating portion 441 along the first direction Y is within the above range, it can effectively provide insulation and protection for the edge of the first film layer 431. In Figure 7, W1 represents the dimension of the first insulating portion 441 along the first direction Y.

[0172] For example, the dimension of the second insulating portion 442 along the first direction Y is 0.2 mm to 3 mm, such as 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or any combination of two of the above values. When the dimension of the second insulating portion 442 along the first direction Y is within the above range, it can effectively provide insulation protection for the edge of the second film layer 432. In Figure 7, W2 represents the dimension of the second insulating portion 442 along the first direction Y.

[0173] The thickness of the first insulating layer 44 is basically the same as the thickness of the first active material layer 43, with a thickness difference of ±2μm. Corresponding to the thickness settings of the first film layer 431 and the second film layer 432, the thickness of the first film layer 431 is basically the same as the thickness of the first insulating portion 441, with a thickness difference of ±2μm; the thickness of the second film layer 432 is basically the same as the thickness of the second insulating portion 442, with a thickness difference of ±2μm.

[0174] Accordingly, when the thickness of the first film layer 431 is greater than the thickness of the second film layer 432, the thickness of the first insulating portion 441 is greater than the thickness of the second insulating portion 442.

[0175] For example, the thickness of the first insulating portion 441 is from 10 μm to 100 μm, such as 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm or any range of two of the above values.

[0176] For example, the thickness of the second insulating portion 442 is from 10 μm to 80 μm, such as 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm or any two of the above values.

[0177] In some embodiments, the main material of the first insulating portion 441 includes at least one of inorganic insulating materials and organic insulating materials. In the embodiments of this application, the main material refers to the material with the largest mass percentage.

[0178] For example, the inorganic insulating material includes inorganic ceramic particles, such as one or more of boehmite γ-AlOOH, alumina Al2O3, aluminum hydroxide Al(OH)3, barium sulfate BaSO4, magnesium oxide MgO, magnesium hydroxide Mg(OH)2, calcium oxide CaO, cerium oxide CeO2, zirconium titanate SrTiO3, barium titanate BaTiO3, and magnesium fluoride MgF2. The inorganic particles provide insulation and heat resistance, enhancing the insulation and heat resistance of the edge of the first active material layer 43.

[0179] For example, the organic insulating material includes one or more of polyolefins, epoxy resins, polyacrylic acid (PAA), and styrene-butadiene rubber (SBR). For instance, the polyolefin includes one or more of polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). The organic insulating material has a stronger bond with the first active material layer 43, providing excellent insulation and protection for the first active material layer 43.

[0180] A first insulating portion 441 is disposed outside the first film layer 431, and a second insulating portion 442 is disposed outside the second film layer 432. Lithium ions in the first film layer 431 migrate to the second film layer 432, are extracted from the second film layer 432, and migrate to the second electrode 50. In some embodiments, the second active material layer 53 of the second electrode 50 extends beyond the second film layer 432 along the first direction Y, so that the lithium ions in the second film layer 432 can be substantially received by the second active material layer 53.

[0181] In some embodiments, along the thickness direction X, the projection surface of the second active material layer 53 partially overlaps with the projection surface of the first insulating layer 44. The first insulating layer 44 is located at the edge of the first active material layer 43 along the first direction Y. The partial overlap of the projection surface of the second active material layer 53 and the projection surface of the first insulating layer 44 along the thickness direction X means that the area where lithium ions are released from the first active material layer 43 is smaller than the area where lithium ions are received by the second active material layer 53. This ensures that the lithium ions released from the first active material layer 43 can be largely received by the second active material layer 53, reducing the risk of lithium plating on the second electrode 50. In the embodiments of this application, the projection surface along the thickness direction X refers to the thickness direction X being parallel to the normal of the projection surface, i.e., the thickness direction X is perpendicular to the projection surface.

[0182] In some embodiments, the second active material layer 53 can be a single-layer film or a multi-layer film. When the second active material layer 53 is a multi-layer film, it can be two or more layers, such as two, three, four, etc. Taking a two-layer second active material layer as an example: the second active material layer 53 includes a third film layer 531 and a fourth film layer 532. The third film layer 531 is disposed on at least one surface of the second current collector 51 along the thickness direction X, and the fourth film layer 532 is disposed on the surface of the third film layer 531 opposite to the second current collector 51.

[0183] When the second electrode 50 includes a second insulating layer 54, the second insulating layer 54 is connected to the third film layer 531 and the fourth film layer 532. Specifically, the third film layer 531 includes two third surfaces 5310 facing each other along the first direction Y, and the fourth film layer 532 includes two fourth surfaces 5320 facing each other along the first direction Y. The second end face 530 includes both the third surface 5310 and the fourth surface 5320, and both the third surface 5310 and the fourth surface 5320 are connected to the second insulating layer 54. The provision of the second insulating layer 54 also makes the overall stress on the second electrode 50 more uniform. Of course, the second electrode 50 may also be without the second insulating layer 54.

[0184] The dimensions of the third film layer 531 and the fourth film layer 532 in the first direction Y can be equal or unequal. Optionally, the dimensions of the third film layer 531 and the fourth film layer 532 in the first direction Y are unequal. For example, the third film layer 531 extends beyond the fourth film layer 532 in the first direction Y, and the dimension of the third film layer 531 in the first direction Y is greater than the dimension of the fourth film layer 532 in the first direction Y. The third film layer 531 can extend beyond the second film layer 432 in the first direction Y, which is beneficial to increasing the capacity of the negative electrode sheet, thereby increasing the energy density of the battery cell 7.

[0185] Optionally, along the thickness direction X, the projection surface of the third film layer 531 partially overlaps with the projection surface of the first insulating layer 44. Since the size of the third film layer 531 in the first direction Y is larger than the size of the fourth film layer 532, and the edge of the third film layer 531 in the first direction Y is the edge of the second active material layer 53, the area of ​​the third film layer 531 that receives lithium ions is larger than the area of ​​the first active material layer 43 that releases lithium ions, thereby reducing the risk of lithium plating on the third film layer 531 in the second electrode 50.

[0186] Alternatively, along the thickness direction X, the projection surface of the fourth film layer 532 partially overlaps with the projection surface of the first insulating layer 44. Since the size of the third film layer 531 in the first direction Y is larger than the size of the fourth film layer 532, when the projection surfaces of the fourth film layer 532 and the first insulating layer 44 partially overlap, the area of ​​the second active material layer 53 that receives lithium ions can be further increased, reducing the risk of lithium plating on the second electrode 50.

[0187] When the third film layer 531 extends beyond the fourth film layer 532 along the first direction Y, the third film layer 531 includes a film layer body 5311 and a film layer extension 5312. The film layer body 5311 and the fourth film layer 532 are disposed opposite each other along the thickness direction X. The film layer extension 5312 is connected to at least one side of the film layer body 5311 along the first direction Y, and the film layer extension 5312 extends beyond the fourth film layer 532.

[0188] Optionally, the surface of the film extension 5312 facing away from the film body 5311 is flush with the surface of the first insulating layer 44 facing away from the first active material layer 43. This arrangement allows the first electrode 40 to apply uniform pressure to the film extension 5312, resulting in more uniform lithium deposition at the film extension 5312, improved deposition morphology, and reduced risk of lithium plating. In Figure 6, S3 represents the surface of the first insulating layer 44 facing away from the first active material layer 43, and S4 represents the surface of the film extension 5312 facing away from the film body 5311.

[0189] Optionally, the first insulating layer 44 extends beyond the film extension portion 5312 along the first direction Y. The first insulating layer 44 can cover foreign objects such as burrs on the second electrode 50, further reducing the risk of short circuit between the positive and negative electrodes and improving the reliability of the battery cell 7.

[0190] For example, the dimension of the film extension 5312 along the first direction Y is 0.2 mm to 5 mm, such as 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, 5 mm, or any combination of two of the above values. When the dimension of the film extension 5312 along the first direction Y is within the above range, the area of ​​the second active material layer 53 that receives lithium ions can be increased, reducing the risk of lithium plating on the second electrode 50. In Figure 6, L1 represents the dimension of the film extension 5312 along the first direction Y.

[0191] Optionally, the thickness of the third film layer 531 is from 0.005 μm to 100 μm, for example, 0.005 μm, 0.01 μm, 0.1 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm or any range of two of the above values.

[0192] Optionally, the thickness of the fourth film layer 532 is from 0.05 μm to 100 μm, for example, 0.05 μm, 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm or any range of two of the above values.

[0193] The thickness of the second insulating layer 54 is basically the same as the thickness of the second active material layer 53, with a thickness difference of ±2μm.

[0194] In this embodiment of the application, the battery cell 7 can be a lithium-ion battery or a lithium metal battery.

[0195] When the battery cell 7 is a lithium metal battery, the second electrode 50 is the negative electrode, and the active material in the second active material layer 53 refers to a material that can induce lithium deposition or a material that can intercalate lithium.

[0196] It may include lithium metal or not.

[0197] Optionally, the second active material layer 53 may include an active material capable of inducing lithium metal deposition, such as a conductive agent (at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, silicon carbide, silicon oxides, graphene, and carbon fibers). Optionally, the active material in the fourth film layer 532 may include at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, silicon carbide, silicon oxides, graphene, and carbon nanofibers. Optionally, the fourth film layer 532 may include at least one selected from carbon nanotube fibers and graphene. The above materials have a high specific surface area, which can reduce the local current density, induce lithium deposition, improve the morphology of lithium deposition, and alleviate dendrite formation.

[0198] Optionally, the active material in the fourth film layer 532 may also include lithium metal.

[0199] When the battery cell 7 is a lithium-ion battery, the second electrode 50 is a negative electrode, and the second active material layer 53 may include a negative active material.

[0200] Optionally, the active material in the fourth film layer 532 may include graphite materials, such as at least one of artificial graphite and natural graphite, which have excellent kinetic properties.

[0201] In some embodiments, whether lithium-ion or lithium-metal batteries, the active material in the third film layer 531 may include one or more of the following: silicon-based materials, graphite materials, gold-based materials, silver-based materials, tin-based materials, bismuth-based materials, magnesium-based materials, zinc-based materials, and phosphorus-based materials. These types of active materials have relatively high specific capacity, which is beneficial for improving the energy density of the battery cell 7. For example, high-specific-capacity graphite materials have a specific capacity of 350 mAh / g to 370 mAh / g.

[0202] For example, silicon-based materials may include at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.

[0203] For example, gold-based materials may include at least one of elemental magnesium, gold oxides, and gold alloys.

[0204] For example, silver-based materials may include at least one of elemental zinc, silver oxides, and silver alloys.

[0205] For example, tin-based materials may include at least one of elemental tin, tin oxides, and tin alloys.

[0206] For example, bismuth-based materials may include at least one of elemental bismuth, bismuth oxides, and bismuth alloys.

[0207] For example, magnesium-based materials may include at least one of elemental magnesium, magnesium oxides, and bismuth alloys.

[0208] For example, zinc-based materials may include at least one of elemental zinc, zinc oxide compounds, and bismuth alloys.

[0209] For example, phosphorus-based materials may include at least one of black phosphorus and red phosphorus.

[0210] In one specific embodiment of this application, the battery cell 7 includes a first electrode 40 and a second electrode 50 with opposite polarities. The first electrode 40 includes a first current collector 41, a first tab 42, a first active material layer 43, and a first insulating layer 44. The first tab 42 is connected to at least one side of the first current collector 41. The first active material layer 43 is disposed on two surfaces of the first current collector 41 along the thickness direction X of the first electrode 40. The first active material layer 43 includes two first end faces 430 facing each other along the first direction Y. The first insulating layer 44 is disposed at least on the surface of the first current collector 41 and connected to the two first end faces 430. The surface of the first insulating layer 44 facing away from the first current collector 41 is flush with the surface of the first active material layer 43 facing away from the first current collector 41. The first electrode 40 is a positive electrode, and the second electrode 50 is a negative electrode.

[0211] Therefore, by providing a first insulating layer 44 on the first end face 430 of the first active material layer 43, the first insulating layer 44 can reduce the risk of short circuit between the first electrode 40 and the second electrode 50, thereby improving the reliability of the battery cell 7. Furthermore, the first electrode 40 can apply uniform stress to the second electrode 50, which can improve the lithium deposition morphology, reduce the risk of lithium dendrite formation, and further improve the reliability of the battery cell 7.

[0212] 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 as long as 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, comprising first and second polar tabs of opposite polarity, the first polar tab comprising: a first current collector; a first tab portion connected to at least one side of the first current collector; a first active material layer disposed on at least one surface of the first current collector in a thickness direction of the first polar tab, the first active material layer comprising two first end faces opposite to each other in a first direction parallel to a direction from the first current collector to the first tab portion; and a first insulating layer disposed on at least one surface of the first current collector and connected to at least one of the first end faces. a surface of the first insulating layer facing away from the first current collector is flush with a surface of the first active material layer facing away from the first current collector. the first active material layer comprises: a first film layer disposed on at least one surface of the first current collector in the thickness direction, the first film layer comprising two first faces opposite to each other in the first direction; and a second film layer disposed on a surface of the first film layer facing away from the first current collector, the second film layer comprising two second faces opposite to each other in the first direction, wherein the first end faces comprise the first faces and the second faces, and the first faces and the second faces are both connected to the first insulating layer. the first film layer extends beyond the second film layer in the first direction. the first insulating layer comprises: a first insulating portion disposed on a surface of the first current collector and connected to the first faces; and a second insulating portion disposed on a surface of the first insulating portion facing away from the first current collector and connected to the second faces. a surface of the second insulating portion facing away from the second film layer is flush with a surface of the first insulating portion facing away from the first film layer. 7.The battery cell of claim 5 or 6, wherein: a dimension of the first insulating portion in the first direction is 0.5 mm to 15 mm; and / or a dimension of the second insulating portion in the first direction is 0.2 mm to 3 mm. a main material of the first insulating layer comprises at least one of an inorganic insulating material and an organic insulating material. 9.The battery cell of claim 8, wherein: the inorganic insulating material comprises inorganic particles comprising one or more of boehmite, alumina, aluminum hydroxide, barium sulfate, magnesium oxide, magnesium hydroxide, calcium oxide, cerium oxide, zirconium titanate, barium titanate, and magnesium fluoride; and / or the organic insulating material comprises one or more of polyolefin, epoxy resin, polyacrylic acid, and styrene butadiene rubber. the second polar tab comprises a second current collector and a second active material layer disposed on at least one surface of the second current collector in the thickness direction, and the second active material layer and the first active material layer are oppositely disposed in the thickness direction. the first polar tab is a positive polar tab, and the second polar tab is a negative polar tab; in the thickness direction, a projection surface of the second active material layer partially overlaps with a projection surface of the first insulating layer. the second active material layer comprises: a third film layer disposed on at least one surface of the second current collector in the thickness direction; and ​ ​ ​ ​ ​ 2. The battery cell of claim 1, wherein, ​ 3. The battery cell of claim 1 or 2, wherein, ​ ​ ​ ​ 4. The battery cell of claim 3, wherein, ​ 5. The battery cell of claim 3 or 4, wherein, ​ ​ ​ 6. The battery cell of claim 5, wherein, ​ ​ ​ ​ 8. The battery cell of any one of claims 1 to 7, wherein, ​ ​ ​ ​ 10. The battery cell of any one of claims 1 to 9, wherein, ​ 11. The battery cell of claim 10, wherein, ​ ​ 12. The battery cell of claim 10 or 11, wherein, ​ ​ a fourth film layer disposed on a surface of the third film layer facing away from the second current collector, wherein the third film layer extends beyond the fourth film layer in the first direction.

13. The battery cell of claim 12, wherein, In the thickness direction, a projection surface of the third film layer partially overlaps a projection surface of the first insulating layer.

14. The battery cell of claim 12 or 13, wherein, In the thickness direction, a projection surface of the fourth film layer partially overlaps a projection surface of the first insulating layer.

15. The battery cell of any one of claims 12-14, wherein, The third film layer includes: a film layer body disposed opposite the fourth film layer in the thickness direction; and a film layer extension connected to at least one side of the film layer body in the first direction, and extending beyond the fourth film layer, wherein the first insulating layer extends beyond the film layer extension in the first direction.

16. The battery cell of claim 15, wherein, A dimension of the film layer extension in the first direction is 0.2 mm to 5 mm.

17. The battery cell of any one of claims 10-16, wherein, The second active material layer includes two second end surfaces opposite each other in the first direction; The second tab further includes a second insulating layer disposed on at least a surface of the second current collector and connected to at least one of the second end surfaces.

18. An electrode tab, comprising: a first current collector; a first tab portion connected to at least one side of the first current collector; a first active material layer disposed on at least one surface of the first current collector in a thickness direction of the first tab, the first active material layer including two first end surfaces opposite each other in a first direction parallel to a direction from the first current collector to the first tab portion; and a first insulating layer disposed on at least a surface of the first current collector and connected to at least one of the first end surfaces.

19. The electrode patch of claim 18, wherein, A surface of the first insulating layer facing away from the first current collector is flush with a surface of the first active material layer facing away from the first current collector.

20. The electrode panel of claim 18 or 19, wherein, The first active material layer includes: a first film layer disposed on at least one surface of the first current collector in the thickness direction, the first film layer including two first surfaces opposite each other in the first direction; and a second film layer disposed on a surface of the first film layer facing away from the first current collector, the second film layer including two second surfaces opposite each other in the first direction, wherein the first end surfaces include the first surfaces and the second surfaces, and the first surfaces and the second surfaces are both connected to the first insulating layer.

21. The electrode patch of claim 20, wherein, The first film layer extends beyond the second film layer in the first direction.

22. The electrode panel of claim 20 or 21, wherein, The first insulating layer includes: a first insulating portion disposed on a surface of the first current collector and connected to the first surfaces; and a second insulating portion disposed on a surface of the first insulating portion facing away from the first current collector and connected to the second surfaces.

23. The electrode patch of claim 22, wherein, A surface of the second insulating portion facing away from the second film layer is flush with a surface of the first insulating portion facing away from the first film layer.

24. The electrode tab according to claim 22 or 23, wherein a dimension of the first insulating portion in the first direction is 0.5 mm to 15 mm; and / or a dimension of the second insulating portion in the first direction is 0.2 mm to 3 mm.

25. A battery including the battery cell according to any one of claims 1 to 17.

26. An electrically powered device comprising the battery of claim 25.

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