Battery cell, related device, system and charging network

Abstract

The utility model is applicable to the technical field of power batteries, and provides a single battery, a related device, a system and a charging network, the single battery comprises a pole piece, the pole piece comprises a current collector, the current collector comprises a main body part and a tab part connected to the main body part, and the tab part extends from one side of the main body part in the width direction of the current collector to the direction away from the main body part; the insulating layer is arranged on the tab part and covers at least part of the tab part, and the insulating layer is positioned on one side, close to the main body part, of the tab part; according to the battery monomer provided by the embodiment of the invention, the insulating layer is arranged and covers at least part of the tab part, so that the strength of the tab part is increased and the bending amplitude of the tab part is reduced through the insulating layer, the risk of short circuit caused by the fact that the tab part is bent and inserted into the gap of the pole piece is reduced, and the safety performance and the stability of the battery monomer are improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a battery cell, a battery device, an energy storage device, an energy storage system, an electrical device, and a charging network. Background Art

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

[0003] During assembly after the tabs are welded, the downward pressure of the end caps can cause the tabs to be inserted between adjacent pole pieces, resulting in a short circuit. Additionally, collisions and vibrations in the battery cells during use can also cause the tabs to be inserted between adjacent pole pieces, resulting in a short circuit. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery device, an energy storage device, an energy storage system, an electrical device and a charging network to improve the problem that the tabs are easily inserted between the pole pieces and cause a short circuit.

[0005] In a first aspect, some embodiments of the present application provide a battery cell, comprising a pole piece, the pole piece comprising: a current collector, the current collector comprising a main body and a pole ear portion connected to the main body portion, the pole ear portion extending from one side of the main body portion along the width direction of the current collector toward a direction away from the main body portion; an insulating layer, provided on the pole ear portion and covering at least a portion of the pole ear portion, the insulating layer being located on a side of the pole ear portion close to the main body portion.

[0006] In the technical solution of this embodiment, an insulating layer is provided, and the insulating layer covers at least a portion of the pole ear portion, so as to increase the strength of the pole ear portion through the insulating layer and reduce the bending amplitude of the pole ear portion, thereby reducing the risk of short circuit caused by the bending of the pole ear portion and insertion into the gap between the pole sheets, thereby improving the safety performance and stability of the battery cell.

[0007] In some embodiments, there are at least two pole lugs and they are spaced apart along the length direction of the current collector; there are at least two insulating layers and they are arranged corresponding to the pole lugs, and each insulating layer is spaced apart along the length direction of the current collector.

[0008] In the technical solution of this embodiment, the insulating layer is arranged corresponding to the pole ear portion, so that the insulating layer is mainly used to improve the strength of the pole ear portion; at the same time, the insulating layers are arranged at intervals to reduce the space occupied by the portion of the insulating layer that does not cover the pole ear portion, thereby reducing the negative impact of the insulating layer on the energy density of the battery cell.

[0009] In some embodiments, in the length direction of the current collector, the size of the insulating layer is smaller than or equal to the size of the electrode tab.

[0010] The technical solution of this embodiment provides some insulating layers covering the size range of the pole ear portion in the length direction of the current collector. On the premise that the insulating layer can improve the strength of the pole ear portion, the insulating layer is not easy to extend beyond the pole ear portion, so as to better reduce the space occupied by the insulating layer, thereby better reducing the negative impact of the insulating layer on the energy density of the battery cell.

[0011] In some embodiments, on the same projection plane perpendicular to the thickness direction of the current collector, the orthographic projection of the insulating layer and the orthographic projection of the pole ear portion at least partially overlap, and the ratio of the orthographic projection of the insulating layer to the orthographic projection of the pole ear portion in the width direction of the current collector is less than or equal to 1:3.

[0012] The technical solution of this embodiment provides some insulating layers covering the size range of the pole ear portion in the width direction of the current collector, so that the insulating layer can not only improve the strength of the pole ear portion to reduce the bending amplitude of the pole ear portion, but also reduce the negative impact of the insulating layer on the conductive performance of the pole ear portion.

[0013] In some embodiments, the yield strength of the insulating layer is greater than or equal to 25 MPa.

[0014] The technical solution of this embodiment provides a yield strength range for some insulating layers, so that the insulating layer can better provide support for the pole ear to reduce the bending amplitude of the pole ear, thereby making it less likely for the pole ear to be inserted between adjacent pole pieces to cause a short circuit, and better improving the stability and safety of the battery cell.

[0015] In some embodiments, the yield strength of the insulating layer is less than or equal to 100 MPa.

[0016] The technical solution of this embodiment further provides some yield strength ranges of the insulating layer. On the premise that the insulating layer can provide support for the pole ear, this setting also limits the upper limit of the yield strength of the insulating layer, so that the pole ear can have a certain bending ability to meet the requirements of electrical connection between the pole ear and the external structure, and can reduce the negative impact of the pole ear on the energy density of the battery cell; at the same time, this setting can also reduce the requirements for the material and thickness of the insulating layer, so as to reduce processing difficulty and reduce costs.

[0017] In some embodiments, the thickness of the insulating layer is greater than or equal to 9 μm.

[0018] The technical solution of this embodiment provides some thickness ranges of the insulating layer. Since the thickness of the insulating layer is positively correlated with the supporting performance of the insulating layer, the thickness of the insulating layer is made greater than or equal to 9 μm to limit the lower limit of the supporting performance that the insulating layer can provide for the pole ear, thereby making it difficult for the pole ear to be inserted between the pole pieces.

[0019] In some embodiments, the thickness of the insulating layer ranges from 9 μm to 30 μm.

[0020] The technical solution of this embodiment further provides some thickness ranges of the insulating layer. On the premise that the insulating layer can provide support for the pole ear, this setting also limits the upper limit of the thickness of the insulating layer, so that the pole ear can have a certain bending ability to meet the requirements of electrical connection between the pole ear and the external structure, and can reduce the negative impact of the pole ear on the energy density of the battery cell; at the same time, this setting can also reduce the space occupied by the insulating layer and reduce the negative impact of the insulating layer on the energy density of the battery cell.

[0021] In some embodiments, the main body includes two end surfaces at opposite ends along the width direction of the current collector, the main body also includes two side surfaces located on opposite sides along the thickness direction of the current collector, and the pole ear portion is formed on the end surface; the pole piece also includes an active material layer provided on the side surface, and the active material layer covers at least part of the side surface; on the same projection plane perpendicular to the thickness direction of the current collector, the orthographic projection of the insulating layer and the orthographic projection of the side surface at least partially overlap.

[0022] In the technical solution of this embodiment, the insulating layer can not only cover the pole ear portion, but also cover the side surface of the main body portion and / or part of the active material layer, so that the insulating layer can not only provide support for the pole ear portion, but also improve the connection strength between the pole ear portion and the main body portion, so that the pole ear portion is not easily torn at the connection portion between it and the main body portion, further improving the safety performance and stability of the battery cell.

[0023] In some embodiments, the insulating layer includes two sub-insulating layers corresponding to the two side surfaces, the sub-insulating layer includes a first portion and a second portion connected to the first portion, the first portion covers at least a portion of the pole ear portion; on the same projection plane perpendicular to the thickness direction of the current collector, the orthographic projection of the second portion overlaps with at least a portion of the orthographic projection of the side surface.

[0024] The technical solution of this embodiment provides some specific structures of the insulating layer, so that the insulating layer is formed by two sub-insulating layers connected to each other; the sub-insulating layer includes a first part and a second part, the first part covers at least part of the pole ear part, and the second part covers part of the side part, so that the insulating layer can not only improve the strength of the pole ear part, but also improve the connection strength between the pole ear part and the main body part.

[0025] In some embodiments, the active material layer covers a portion of the corresponding side surface and forms a blank area on a side of the side surface close to the electrode ear portion, and the second portion covers at least a portion of the blank area.

[0026] In the technical solution of this embodiment, the second part can cover at least part of the blank area to protect the main body, while also reducing the area of ​​the main body exposed to the outside, thereby reducing the occurrence of short circuits and improving the safety performance of the battery cell.

[0027] In some embodiments, the sub-insulating layer further includes a third portion connected to a side of the second portion opposite to the first portion, the second portion covers the blank area, and the third portion covers a portion of the active material layer.

[0028] In the technical solution of this embodiment, the sub-insulating layer further includes a third portion, and the third portion covers a portion of the active material layer, so that the second portion can completely cover the blank area, thereby further improving the safety performance of the battery cell.

[0029] In some embodiments, on a projection plane perpendicular to the thickness direction of the current collector, a size of an orthographic projection of the third portion ranges from 0.1 mm to 1 mm.

[0030] The technical solution of this embodiment provides some dimensions of the third part in the width direction of the current collector. On the premise that the third part can cover the active material layer, the dimension of the third part in the width direction of the current collector is made smaller to reduce the negative impact of the third part on the charge and discharge capacity of the active material layer.

[0031] In some embodiments, the active material layer completely covers the corresponding side surface, and the second portion covers a portion of the active material layer.

[0032] In the technical solution of this embodiment, the active material layer completely covers the side of the main body so that there is a larger contact area between the active material layer and the electrolyte, thereby making the active material layer have better charging and discharging capabilities; the second part covers part of the active material layer so that the insulating layer can not only improve the strength of the pole ear part, but also improve the connection strength of the connection between the pole ear part and the main body part.

[0033] In some embodiments, on a projection plane perpendicular to the thickness direction of the current collector, a size of an orthographic projection of the second portion ranges from 0.1 mm to 1 mm.

[0034] The technical solution of this embodiment provides some dimensions of the second part in the width direction of the current collector. On the premise that the second part can be connected to the active material layer, the dimension of the second part in the width direction of the current collector is smaller to reduce the negative impact of the second part on the charge and discharge capacity of the active material layer.

[0035] In some embodiments, there are at least two pole lugs and they are spaced apart along the length direction of the current collector; there is one insulating layer, and the insulating layer covers at least one pole lug.

[0036] In the technical solution of this embodiment, there is only one insulating layer, and one insulating layer can cover one or more pole lugs, so that the insulating layer can not only increase the strength of the pole lug and reduce the bending amplitude of the pole lug, but also reduce the difficulty of processing and setting the insulating layer.

[0037] In some embodiments, the insulating layer includes a substrate layer and an adhesive layer disposed on the substrate layer. The adhesive layer is disposed on a side of the substrate layer facing the current collector, and the adhesive layer is at least connected to the electrode tab.

[0038] The technical solution of this embodiment provides some sub-insulating layer structures, so that the sub-insulating layer includes an adhesive layer and a substrate layer, so that the substrate layer can be connected to the pole ear part through the adhesive layer, so that the substrate layer can provide support for the pole ear part and improve the strength of the pole ear part, and the substrate layer can also play a role in protecting the pole ear part.

[0039] In some embodiments, a battery cell includes an electrode assembly, the electrode assembly includes a tab, and the tab includes at least two stacked tab portions.

[0040] The technical solution of this embodiment provides a specific structure of the electrode tabs of some electrode assemblies, so that the electrode tabs include at least two stacked electrode tab portions, and each electrode tab portion is provided with an insulating layer. At this time, the electrode tabs of the electrode assembly can have higher strength under the support of multiple insulating layers, making it more difficult for the electrode tabs to be inserted between the electrode sheets.

[0041] In some embodiments, at least a portion of each tab portion is flattened.

[0042] The technical solution of this embodiment provides a specific structure of the tabs of some electrode assemblies, so that at least part of each tab portion is flattened to form the tab, so that the electrode assembly can meet the needs of cylindrical battery cells, etc.

[0043] In a second aspect, some embodiments of the present application further provide a battery device, comprising the battery cell provided by some embodiments of the first aspect.

[0044] In a third aspect, some embodiments of the present application further provide an energy storage device, comprising a plurality of battery cells provided by some embodiments of the first aspect, or a plurality of battery devices provided by some embodiments of the second aspect;

[0045] Battery cells or battery devices are used to store or provide electrical energy.

[0046] In a fourth aspect, some embodiments of the present application further provide an energy storage system, comprising a power conversion device and the energy storage device provided by some embodiments of the third aspect, wherein the power conversion device is used to electrically connect the power generation device and the energy storage device.

[0047] In a fifth aspect, some embodiments of the present application also provide an electrical device, including the battery cells provided by some embodiments of the first aspect, the battery devices provided by some embodiments of the second aspect, the energy storage devices provided by some embodiments of the third aspect, or the energy storage systems provided by some embodiments of the fourth aspect, wherein the battery cells or battery devices are used to store or provide electrical energy.

[0048] In a sixth aspect, some embodiments of the present application further provide a charging network, comprising a charging pile and the energy storage device provided by some embodiments of the third aspect, or the energy storage system provided by some embodiments of the fourth aspect;

[0049] The energy storage device or energy storage system is used to provide electrical energy to the charging pile.

[0050] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0052] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0053] Figure 2 Schematic diagram of the exploded structure of a battery device according to some embodiments of the present application;

[0054] Figure 3 A schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application;

[0055] Figure 4 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application;

[0056] Figure 5 A schematic diagram of the three-dimensional structure of an electrode assembly provided in some embodiments of the present application;

[0057] Figure 6 A schematic diagram of the structure of the pole piece provided in some embodiments of the present application;

[0058] Figure 7 Some embodiments of this application provide Figure 6 Schematic cross-sectional view at AA in the middle;

[0059] Figure 8 For other embodiments of this application Figure 6 Schematic cross-sectional view at AA in the middle;

[0060] Figure 9 Some embodiments of the present application provide Figure 6 Schematic cross-sectional view at AA in the middle;

[0061] Figure 10 for Figure 8 A partial enlarged schematic diagram of point B in the middle;

[0062] Figure 11 Schematic diagrams of exploded structures of battery devices according to other embodiments of the present application;

[0063] Figure 12 Schematic diagram of the explosion structure of battery cells in other embodiments of the present application;

[0064] Figure 13 A schematic diagram of the structure of an energy storage system provided in some embodiments of the present application;

[0065] Figure 14 A schematic diagram of the structure of a charging network provided in some embodiments of the present application.

[0066] The meanings of the marks in the figure are:

[0067] 1. Energy storage device; 2. Power conversion device; 3. Power generation device; 4. Charging pile; 5. Connector;

[0068] 1000. Battery device;

[0069] 100. Battery cell;

[0070] 10. Electrode assembly; 11. Pole piece; 111. Current collector; 1111. Main body; 1111a. End face; 1111b. Side face; 1111c. Blank area; 1112. Tab; 112. Insulating layer; 1121. Sub-insulating layer; 1121a. First portion; 1121b. Second portion; 1121c. Third portion; 1121d. Base material layer; 1121e. Adhesive layer; 113. Active material layer; 12. Separator; 13. Tab;

[0071] 20. Housing;

[0072] 30. End cap;

[0073] 40. Electrode terminal;

[0074] 200, box body; 201, upper box body; 202, lower box body;

[0075] 2000, motor;

[0076] 3000, controller. DETAILED DESCRIPTION

[0077] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0079] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0080] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0081] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0082] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0083] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0084] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0085] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0086] After the tabs are welded, during assembly, the downward pressure of the end caps can cause portions of the tabs to become inserted between adjacent pole pieces, leading to a short circuit. Specifically, after the tabs of the electrode assembly are connected to the electrode terminals, the electrode assembly is installed in the housing, and then the end caps, carrying the electrode terminals, are fitted to the housing. To reduce the negative impact on the energy density of the battery cells, the space between the electrode assembly and the end caps is typically small, which can cause the tabs to bend after the end caps are fitted. Due to the material of the tabs, the strength of the tabs is typically poor, and this can easily lead to the bent portion of the tab being inserted between the pole pieces, causing a short circuit.

[0087] The above installation process shows that even if the tabs are not inserted between the pole pieces during installation, the risk of the tabs inserting between the pole pieces during subsequent transportation and use of the battery cell remains high due to the strength of the tabs. For example, during use, collisions or vibrations in the battery cell could cause a portion of the tab to be inserted between adjacent pole pieces, resulting in a short circuit.

[0088] Based on the above considerations, in order to alleviate the problem that the pole ear is easily inserted between the pole pieces and causes a short circuit, an embodiment of the present application provides a battery cell, in which an insulating layer is provided on the pole piece of the battery cell to cover at least a portion of the pole ear portion by the insulating layer; at the same time, the insulating layer is located on the side of the pole ear portion close to the main body portion.

[0089] In such a battery cell, the insulating layer can increase the strength of the pole ear to reduce the bending amplitude of the pole ear, thereby reducing the risk of the pole ear being inserted between the pole pieces; the insulating layer is located on the side of the pole ear close to the main body. When the pole ear is deformed, the part of the pole ear covered with the insulating layer is less likely to deform or has a smaller deformation amount, so as to increase the distance between the end of the pole ear away from the main body and the electrode assembly, so that the end of the pole ear away from the main body can have a larger deformation space, thereby further reducing the risk of the pole ear being inserted between the pole pieces.

[0090] The battery cells disclosed in the embodiments of the present application can be used in electrical devices that use the battery device as a power source or various energy storage systems that use the battery device as an energy storage element. The electrical devices may be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, battery-powered vehicles, electric vehicles, ships, spacecraft, and the like. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0091] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0092] refer to Figure 1 , Figure 1 The power-consuming device provided for some embodiments of the present application is a schematic structural diagram of a vehicle. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 1000 is provided inside the vehicle, and the battery device 1000 can be provided at the bottom, head or tail of the vehicle. The battery device 1000 can be used to power the vehicle, for example, the battery device 1000 can serve as an operating power source for the vehicle. The vehicle may also include a controller 3000 and a motor 2000, and the controller 3000 is used to control the battery device 1000 to power the motor 2000, for example, for starting, navigating and operating power requirements of the vehicle during driving.

[0093] In some embodiments of the present application, the battery device 1000 can serve not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0094] refer to Figure 2, Figure 2 Schematic diagram of an exploded structure of a battery device 1000 provided in some embodiments of the present application. The battery device 1000 includes a housing 200 and a battery cell 100, with the battery cell 100 housed within the housing 200. The housing 200 is used to provide a storage space for the battery cell 100, and the housing 200 can adopt a variety of structures. In some embodiments, the housing 200 can include an upper housing 201 and a lower housing 202, which cover each other and together define a storage space for the battery cell 100. The lower box body 202 may be a hollow structure with one end open, and the upper box body 201 may be a plate-like structure, with the upper box body 201 covering the open side of the lower box body 202, so that the upper box body 201 and the lower box body 202 jointly define a storage space. The upper box body 201 and the lower box body 202 may also be hollow structures with one end open, with the open side of the upper box body 201 covering the open side of the lower box body 202. Of course, the box body 200 formed by the upper box body 201 and the lower box body 202 may have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0095] In the battery device 1000, there may be multiple battery cells 100, and the multiple battery cells 100 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 100. The multiple battery cells 100 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery unit formed by the multiple battery cells 100 may be housed within the housing 200. Of course, the battery device 1000 may also be a battery module formed by first connecting multiple battery cells 100 in series, in parallel, or in a hybrid connection, and then the multiple battery modules are further connected in series, in parallel, or in a hybrid connection to form an entire battery unit, which is then housed within the housing 200. The battery device 1000 may also include other structures, for example, the battery device 1000 may further include a busbar component for achieving electrical connection between the multiple battery cells 100.

[0096] Each battery cell 100 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 100 may be cylindrical, flat, rectangular, or in other shapes.

[0097] refer to Figure 2 、 Figure 3 , the battery cell 100 refers to the smallest unit that constitutes the battery device 1000. Figure 3 The battery cell 100 includes an end cap 30 , a shell 20 , an electrode assembly 10 and other functional components.

[0098] The end cap 30 is a component that covers the opening of the housing 20 to isolate the internal environment of the battery cell 100 from the external environment. The shape of the end cap 30 can be adapted to the shape of the housing 20 to fit the housing 20. Optionally, the end cap 30 can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the end cap 30 from deforming when subjected to compression or collision, thereby providing the battery cell 100 with greater structural strength and improved safety. Functional components such as electrode terminals 40 can be provided on the end cap 30. The electrode terminals 40 can be used to electrically connect to the electrode assembly 10 for inputting or outputting electrical energy to or from the battery cell 100. In some embodiments, the end cap 30 can also be provided with a pressure relief mechanism for relieving internal pressure when the internal pressure or temperature of the battery cell 100 reaches a threshold. The end cap 30 can also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this. In some embodiments, an insulating member may be provided inside the end cap 30 to isolate the electrical connection components in the housing 20 from the end cap 30 to reduce the risk of short circuit.

[0099] The housing 20 is a component that cooperates with the end cap 30 to form an internal environment for the battery cell 100. This internal environment can be used to accommodate the electrode assembly 10, electrolyte, and other components. The housing 20 and end cap 30 can be separate components. An opening can be provided in the housing 20, and the end cap 30 is placed over the opening to form the internal environment of the battery cell 100. Alternatively, the end cap 30 and housing 20 can be integrated. Specifically, the end cap 30 and housing 20 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 20 needs to be enclosed, the end cap 30 is placed over the housing 20. The housing 20 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 20 can be determined based on the specific shape and size of the electrode assembly 10. The housing 20 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0100] The electrode assembly 10 is a component in the battery cell 100 where electrochemical reactions occur. One or more electrode assemblies 10 may be contained in the housing 20. The electrode assembly 10 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator 12 is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly 10, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab 13. The positive electrode tab 13 and the negative electrode tab 13 may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery device 1000, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab 13 connects to the electrode terminal 40 to form a current loop.

[0101] First, reference Figures 4 to 9 The present invention provides a battery cell 100 including a pole piece 11, which includes a current collector 111 and an insulating layer 112. The current collector 111 includes a main body 1111 and a tab 1112 connected to the main body 1111. The tab 1112 extends from one side of the main body 1111 along the width of the current collector 111 in a direction away from the main body 1111. The insulating layer 112 is provided on the tab 1112 and covers at least a portion of the tab 1112. The insulating layer 112 is located on the side of the tab 1112 that is close to the main body 1111.

[0102] In the figure, the direction of the X-axis is the length direction of the electrode 11, which is also the length direction of the current collector 111; the direction of the Y-axis is the width direction of the electrode 11, which is also the width direction of the current collector 111; the direction of the Z-axis is the thickness direction of the electrode 11, which is also the thickness direction of the current collector 111.

[0103] The current collector 111 refers to the structure in the electrode 11 that is mainly used to support the flow of current. The main function of the current collector 111 is to provide an ion conductor in the electrochemical reaction to support the flow of current and separate the chemical reaction between the positive and negative electrodes, so that the electron flow flows in the external circuit, thereby generating electrical energy. For example, in the lithium-ion battery device 1000, the current collector 111 can be a structural member made of copper foil, aluminum foil or other materials.

[0104] The main body 1111 refers to the partial structure of the current collector 111 used to carry the active material, and the active material can be formed on the main body 1111; the pole ear 1112 refers to the partial structure of the current collector 111 extending outward from the main body 1111, and the pole ear 1112 is used to make the pole piece 11 conductive with the circuit outside the electrode assembly 10; the pole ear 1112 extends from one side of the main body 1111 to the outside of the main body 1111, and the pole ear 1112 extends along the width direction Y of the current collector 111; the pole ear 1112 can be integrally formed with the main body 1111, or can be connected to the main body 1111 by gluing, welding, etc.; there can be one pole ear 1112, or there can be two or more pole ear portions.

[0105] The insulating layer 112 refers to a layered structure in the pole piece 11 that is mainly used to improve the strength of the pole ear portion 1112. The insulating layer 112 is arranged on the pole ear portion 1112 to improve the strength of the pole ear portion 1112, thereby limiting the bending amplitude of the pole ear portion 1112; the insulating layer 112 covers at least part of the pole ear portion 1112, that is, the insulating layer 112 can completely cover the pole ear portion 1112, or can only cover part of the pole ear portion 1112.

[0106] It is understandable that when the insulation layer 112 completely covers the pole ear portion 1112 , part of the pole ear portion 1112 can be exposed by cutting, melting, etc., so as to facilitate electrical connection between the pole ear portion 1112 and an external structure (such as the electrode terminal 40 ).

[0107] The insulating layer 112 is provided on the pole ear portion 1112. Depending on the structure of the insulating layer 112, the insulating layer 112 may be connected to the pole ear portion 1112 by bonding, curing, or other methods. For example, the insulating layer 112 may include insulating tape and be connected to the pole ear portion 1112 by bonding; for example, the insulating layer 112 may also include a coating and be connected to the pole ear portion 1112 by spray curing; it is understood that the insulating layer 112 may also include other structures, not limited to the above two.

[0108] The insulating layer 112 can be arranged only on one side of the pole ear portion 1112, or on both sides of the pole ear portion 1112; for example, since the current collector 111 is a sheet structure, that is, the pole ear portion 1112 has two surfaces with larger areas in the thickness direction Z of the current collector 111, the insulating layer 112 can cover only one of the two surfaces, or cover both surfaces at the same time.

[0109] The insulating layer 112 is arranged on the side of the pole ear portion 1112 close to the main body portion 1111, that is, the insulating layer 112 is located at the root of the pole ear portion 1112, so that the root of the pole ear portion 1112 is less likely to bend or the bending amplitude is smaller; at this time, the part of the pole ear portion 1112 away from the root can have a larger gap with the main body portion 1111 during the bending process, so that the pole ear portion 1112 is less likely to be inserted between adjacent pole pieces 11 and short-circuited with the main body portion 1111.

[0110] The insulating layer 112 can be connected only to the pole ear portion 1112, or it can be connected to the pole ear portion 1112 and the main body portion 1111 at the same time. In this case, in addition to improving the strength of the pole ear portion 1112, the insulating layer 112 can also improve the connection strength of the connection between the pole ear portion 1112 and the main body portion 1111, so as to reduce the risk of tearing of the pole ear portion 1112.

[0111] In this embodiment, an insulating layer 112 is provided, and the insulating layer 112 covers at least a portion of the pole ear portion 1112, so as to increase the strength of the pole ear portion 1112 through the insulating layer 112 and reduce the bending amplitude of the pole ear portion 1112, thereby reducing the risk of the pole ear portion 1112 bending and inserting into the gap of the pole piece 11 and causing a short circuit, thereby improving the safety performance and stability of the battery cell 100.

[0112] refer to Figures 6 to 9 In some embodiments, there are at least two pole ear portions 1112 and they are spaced apart along the length direction of the current collector 111 ; there are at least two insulating layers 112 and they are arranged corresponding to the pole ear portions 1112 , and each insulating layer 112 is spaced apart along the length direction of the current collector 111 .

[0113] The number of the pole ear portions 1112 is at least two, that is, the number of the pole ear portions 1112 can be two, or three or more; the pole ear portions 1112 are arranged at intervals along the length direction X of the current collector 111, so that after the pole piece 11 is wound, at least part of the pole ear portions 1112 can be stacked on each other.

[0114] The number of insulating layers 112 is at least two, that is, the number of insulating layers 112 can be two, or three or more; the insulating layers 112 are arranged corresponding to the pole ear portions 1112, that is, each pole ear portion 1112 is provided with an insulating layer 112, so that the strength of each pole ear portion 1112 can be enhanced by the insulating layer 112.

[0115] The number of insulating layers 112 can be consistent with the number of pole ear portions 1112. In this case, the insulating layers 112 correspond to the pole ear portions 1112 one by one, and each insulating layer 112 covers one pole ear portion 1112. The number of insulating layers 112 can also be different from the number of pole ear portions 1112. The number of insulating layers 112 can be less than the number of pole ear portions 1112. In this case, one insulating layer 112 can correspond to two or more insulating layers 112, and the number of pole ear portions 1112 corresponding to different insulating layers 112 can also be different. The number of insulating layers 112 can also be greater than the number of pole ear portions 1112, that is, two or more insulating layers 112 can also be set on one pole ear portion 1112 along the length direction X of the current collector 111.

[0116] The insulating layers 112 are arranged at intervals along the length direction of the current collector 111 so that the insulating layers 112 can be mainly used to improve the strength of the pole ear portion 1112. At the same time, the intervals between the insulating layers 112 can reduce the space occupied by the insulating layers 112, thereby reducing the negative impact of the insulating layers 112 on the energy density of the battery cell 100.

[0117] In this embodiment, the insulating layer 112 is arranged corresponding to the pole ear portion 1112, so that the insulating layer 112 is mainly used to improve the strength of the pole ear portion 1112; at the same time, the insulating layers 112 are arranged at intervals to reduce the space occupied by the portion of the insulating layer 112 that does not cover the pole ear portion 1112, thereby reducing the negative impact of the insulating layer 112 on the energy density of the battery cell 100.

[0118] refer to Figure 6 In some embodiments, in the length direction of the current collector 111 , the size of the insulating layer 112 is smaller than or equal to the size of the electrode ear portion 1112 .

[0119] The size of the insulating layer 112 in the length direction X of the current collector 111 can be smaller than the size of the pole ear portion 1112 in the length direction X of the current collector 111, or it can be equal to the size of the pole ear portion 1112 in the length direction X of the current collector 111, that is, the insulating layer 112 is located within the pole ear portion 1112 in the length direction X of the current collector 111 and will not extend outside the pole ear portion 1112; at this time, the insulating layer 112 can correspond one-to-one to the pole ear portion 1112, that is, one insulating layer 112 is provided on one pole ear portion 1112.

[0120] On the premise that the insulating layer 112 can improve the strength of the pole ear portion 1112 , this arrangement further reduces the space occupied by the insulating layer 112 , thereby better reducing the negative impact of the insulating layer 112 on the energy density of the battery cell 100 .

[0121] Optionally, the size of the insulating layer 112 in the length direction X of the current collector 111 is equal to the size of the pole ear 1112 in the length direction X of the current collector 111, so that the insulating layer 112 can not only better improve the strength of the pole ear 1112, but also reduce the negative impact of the insulating layer 112 on the energy density of the battery cell 100.

[0122] For example, when the pole ear portion 1112 is a rectangular sheet structure, the shape of the insulating layer 112 may also be rectangular; for example, when the pole ear portion 1112 is a trapezoidal sheet structure, the shape of the insulating layer 112 may also be trapezoidal.

[0123] This embodiment provides some insulating layers 112 covering the size range of the pole ear portion 1112 in the length direction of the current collector 111. On the premise that the insulating layer 112 can improve the strength of the pole ear portion 1112, the insulating layer 112 is not easy to extend beyond the pole ear portion 1112, so as to better reduce the space occupied by the insulating layer 112, thereby better reducing the negative impact of the insulating layer 112 on the energy density of the battery cell 100.

[0124] refer to Figure 6 In some embodiments, on the same projection plane perpendicular to the thickness direction of the current collector 111, the orthographic projection of the insulating layer 112 and the orthographic projection of the pole ear portion 1112 at least partially overlap, and the ratio of the orthographic projection of the insulating layer 112 to the orthographic projection of the pole ear portion 1112 in the width direction of the current collector 111 is less than or equal to 1:3.

[0125] The projection plane perpendicular to the thickness direction of the current collector 111 refers to a virtual plane perpendicular to the thickness direction of the current collector 111 , and the virtual plane is also parallel to the current collector 111 .

[0126] The orthographic projection of the insulating layer 112 on the projection plane refers to the projection of the insulating layer 112 on the projection plane along the direction perpendicular to the projection plane, and is also the projection of the insulating layer 112 on the projection plane along the thickness direction Z of the current collector 111. The orthographic projection of the insulating layer 112 on the projection plane reflects the area of ​​the portion of the insulating layer 112 covering the pole ear 1112. The size of the orthographic projection of the insulating layer 112 on the projection plane in the width direction Y of the current collector 111 is the width of the portion of the insulating layer 112 covering the pole ear 1112, which is the size shown as L0 in the figure.

[0127] The orthographic projection of the pole ear 1112 on the projection plane refers to the projection of the pole ear 1112 on the projection plane along the direction perpendicular to the projection plane, and is also the projection of the pole ear 1112 on the projection plane along the thickness direction Z of the current collector 111. The size of the orthographic projection of the pole ear 1112 on the projection plane in the width direction Y of the current collector 111 is the length of the pole ear 1112, which is the size shown as L in the figure.

[0128] In the width direction of the current collector 111, the ratio between the size of the orthographic projection of the insulating layer 112 on the projection plane and the size of the orthographic projection of the pole ear 1112 on the projection plane is less than or equal to 1:3, that is, the width of the orthographic projection of the insulating layer 112 on the projection plane is less than or equal to 1 / 3 of the width of the pole ear 1112. The ratio can be 1:3, 1:4, 1:5, 1:6 or other ratios.

[0129] Because the pole ear portion 1112 is mainly used to make the pole piece 11 and the circuit outside the electrode assembly 10 conductive, when the pole ear portion 1112 is connected to the external structure, the presence of an insulating layer 112 between the pole ear portion 1112 and the adjacent structure is likely to have a negative impact on the conductive performance of the pole ear portion 1112; when the insulating layer 112 completely covers the pole ear portion 1112, it is necessary to remove the insulating layer 112 at the position where the pole ear portion 1112 is connected to the external structure in order to make the pole ear portion 1112 have better conductive performance. The removal process of the insulating layer 112 is difficult and cumbersome.

[0130] Accordingly, the insulating layer 112 only covers a portion of the pole lug portion 1112 , so that the insulating layer 112 can not only improve the strength of the pole lug portion 1112 , but also reduce the negative impact of the insulating layer 112 on the conductive performance of the pole lug portion 1112 .

[0131] For example, the ratio between the size of the positive projection of the insulating layer 112 on the projection plane and the size of the pole ear portion 1112 is less than or equal to 1:3. At this time, the insulating layer 112 can not only improve the strength of the pole ear portion 1112, but also reduce the negative impact on the conductive performance of the pole ear portion 1112.

[0132] This embodiment provides some insulating layers 112 covering the size range of the pole ear portion 1112 in the width direction of the current collector 111, so that the insulating layer 112 can not only improve the strength of the pole ear portion 1112 to reduce the bending amplitude of the pole ear portion 1112, but also reduce the negative impact of the insulating layer 112 on the conductive performance of the pole ear portion 1112.

[0133] In some embodiments, the yield strength of the insulating layer 112 is greater than or equal to 25 MPa (megapascals).

[0134] Yield strength refers to the stress limit value at which a material begins to undergo obvious plastic deformation when subjected to external force. The yield strength of the insulating layer 112 reflects the ability of the pole ear 1112 to resist deformation under the action of the insulating layer 112. The greater the yield strength of the insulating layer 112, the smaller the bending amplitude of the pole ear 1112 under the same external force, and the less likely the pole ear 1112 is to be inserted between the pole pieces 11 and cause a short circuit. That is, the higher the yield strength of the insulating layer 112, the lower the risk of the pole ear 1112 being inserted between the pole pieces 11.

[0135] The yield strength of the insulating layer 112 may be 25 MPa, or may be 35 MPa, 45 MPa, 55 MPa, 65 MPa, 75 MPa, 85 MPa, 95 MPa, 100 MPa or other values.

[0136] It can be understood that the yield strength of the insulating layer 112 is usually related to the thickness, material, structure, etc. of the insulating layer 112; on the premise that the yield strength of the insulating layer 112 can meet the requirements to reduce the insertion of the pole ear 1112 between the pole pieces 11, the yield strength of the insulating layer 112 can be smaller to reduce the thickness of the insulating layer 112 and reduce the space occupied by the insulating layer 112, and can also reduce the requirements of the insulating layer 112 on materials and structures, and reduce the cost and processing difficulty of the insulating layer 112.

[0137] For example, the yield strength of the insulating layer 112 can be 25 MPa. This setting can not only improve the strength of the pole ear portion 1112 so that the pole ear portion 1112 is not easily inserted between the pole pieces 11, but also reduce the cost and processing difficulty of the insulating layer 112, or reduce the space occupied by the insulating layer 112.

[0138] The yield strength of the insulating layer 112 can be tested through tensile tests, compression tests, bending tests, etc. Since the insulating layer 112 is mainly used to improve the bending resistance of the tab portion 1112, the bending test is used as an example. The insulating layer 112 is made into a specimen, and a bending force is applied to the specimen to cause bending deformation. The stress-strain relationship during this process is recorded to determine the yield strength of the insulating layer 112.

[0139] For example, a sample of the insulating layer 112 can be first made according to the required standard; then the sample is placed on two supporting points of a bending tester and a bending force is applied; the bending force is gradually increased until the sample reaches a specified deflection or breaks, and the stress-deflection data during the bending process is recorded; based on the stress-deflection curve, the bending yield strength of the material is determined.

[0140] This embodiment provides some yield strength ranges of the insulating layer 112, so that the insulating layer 112 can better provide support for the pole ear portion 1112 to reduce the bending amplitude of the pole ear portion 1112, thereby making it less likely for the pole ear portion 1112 to be inserted between adjacent pole pieces 11 and cause a short circuit, and better improving the stability and safety of the battery cell 100.

[0141] In some embodiments where the yield strength of the insulating layer 112 is greater than or equal to 25 MPa, the yield strength of the insulating layer 112 is less than or equal to 100 MPa.

[0142] The yield strength of the insulating layer 112 is less than or equal to 100 MPa, that is, the yield strength of the insulating layer 112 ranges from 25 MPa to 100 MPa; the yield strength of the insulating layer 112 can be 100 MPa, or it can be 100 MPa, 95 MPa, 85 MPa, 75 MPa, 65 MPa, 62.5 MPa, 55 MPa, 45 MPa, 35 MPa, 25 MPa or other values.

[0143] Affected by the space and energy density of the shell 20 of the battery cell 100, the space between the electrode assembly 10 and the top cover should not be too large. Therefore, when the pole ear 1112 is electrically connected to the external structure (such as the electrode terminal 40), the pole ear 1112 still needs to have a certain bending amplitude; accordingly, the yield strength of the insulating layer 112 should not be too large to reduce the difficulty of bending the pole ear 1112, and at the same time, it can also reduce the reaction force on the structure connected to the pole ear 1112 (such as the main body 1111 and the electrode terminal 40).

[0144] For example, the yield strength of the insulating layer 112 can be 62.5 MPa. This setting can further improve the strength of the pole ear portion 1112, so that the pole ear portion 1112 is not easily inserted between the pole pieces 11; this setting can also reduce the cost and processing difficulty of the insulating layer 112, reduce the space occupied by the insulating layer 112, and reduce the stress on the structure connected to the pole ear portion 1112.

[0145] For example, the yield strength of the insulating layer 112 may be 100 MPa. In this case, the insulating layer 112 can better improve the strength of the pole ear portion 1112 , so that the pole ear portion 1112 is less likely to be inserted between the pole pieces 11 , thereby better improving the stability of the battery cell 100 .

[0146] This embodiment further provides some yield strength ranges of the insulating layer 112. On the premise that the insulating layer 112 can provide support for the pole ear portion 1112, this setting also limits the upper limit of the yield strength of the insulating layer 112, so that the pole ear portion 1112 can have a certain bending ability to meet the requirements of electrical connection between the pole ear portion 1112 and the external structure, and can reduce the negative impact of the pole ear portion 1112 on the energy density of the battery cell 100; at the same time, this setting can also reduce the requirements for the material and thickness of the insulating layer 112, so as to reduce processing difficulty and reduce costs.

[0147] refer to Figures 6 to 9 In some embodiments, the thickness of the insulating layer 112 is greater than or equal to 9 μm (micrometers).

[0148] The thickness of the insulating layer 112 can reflect the strength of the insulating layer 112. When the material of the insulating layer 112 is determined, the greater the thickness of the insulating layer 112, the smaller the bending amplitude of the pole ear portion 1112, and the better the reinforcing effect of the insulating layer 112 on the pole ear portion 1112; Figure 7 The thickness of the insulating layer 112 is the dimension of the insulating layer 112 in the thickness direction Z of the current collector 111, which is also the dimension shown by W in the figure.

[0149] The thickness of the insulating layer 112 is greater than or equal to 9 μm. When the thickness of the insulating layer 112 is uniform or approximately uniform everywhere, the thickness of the insulating layer 112 refers to the thickness dimension of the insulating layer 112 at any part, and in this case, the dimension is greater than or equal to 9 μm. When the thickness of the insulating layer 112 is uneven, the thickness of the insulating layer 112 at the smallest thickness should be greater than or equal to 9 μm.

[0150] The thickness of the insulating layer 112 is greater than or equal to 9 μm. For example, the thickness of the insulating layer 112 may be 9 μm, or may be 9 μm, 13 μm, 17 μm, 21 μm, 25 μm, 30 μm, or other values.

[0151] For example, the thickness of the insulating layer 112 is 9 μm. At this time, the insulating layer 112 has a certain strength and can provide support for the pole ear portion 1112, so that the bending amplitude of the pole ear portion 1112 is not too large, thereby making it difficult for the pole ear portion 1112 to be inserted between the pole pieces 11; at the same time, this setting can also reduce the space occupied by the insulating layer 112 and reduce the negative impact of the insulating layer 112 on the energy density of the battery cell 100.

[0152] This embodiment provides some thickness ranges of the insulating layer 112. Since the thickness of the insulating layer 112 is positively correlated with the supporting performance of the insulating layer 112, the thickness of the insulating layer 112 is greater than or equal to 9 μm to limit the lower limit of the supporting performance that the insulating layer 112 can provide for the pole ear portion 1112, thereby making it difficult for the pole ear portion 1112 to be inserted between the pole pieces 11.

[0153] In some embodiments, the thickness of the insulating layer 112 ranges from 9 μm to 30 μm.

[0154] The thickness of the insulating layer 112 is less than or equal to 30 μm. When the thickness of the insulating layer 112 is uniform or approximately uniform everywhere, the thickness of the insulating layer 112 refers to the thickness dimension of the insulating layer 112 at any part, and in this case, the dimension is less than or equal to 30 μm. When the thickness of the insulating layer 112 is uneven, the thickness of the insulating layer 112 at the maximum thickness should be less than or equal to 30 μm.

[0155] Since the setting of the insulating layer 112 will occupy the internal space of the shell 20, and the space occupied by the insulating layer 112 is positively correlated with the thickness of the insulating layer 112, the thickness of the insulating layer 112 is less than or equal to 30μm; on the premise that the insulating layer 112 can increase the strength of the pole ear 1112 so that the pole ear 1112 is not easily inserted between the pole pieces 11, the thickness of the insulating layer 112 should be smaller to reduce the negative impact of the insulating layer 112 on the energy density of the battery cell 100.

[0156] The thickness of the insulating layer 112 is less than or equal to 30 μm. For example, the thickness of the insulating layer 112 may be 30 μm, or may be 25 μm, 21 μm, 17 μm, 13 μm, 9 μm, or other values.

[0157] For example, the thickness of the insulating layer 112 is 30 μm. In this case, the insulating layer 112 has higher strength and can better provide support for the pole ear portion 1112 , so that the pole ear portion 1112 is difficult to be inserted between the pole pieces 11 .

[0158] For example, the thickness of the insulating layer 112 is 19.5 μm. In this case, the insulating layer 112 has high strength to provide support for the tab portion 1112 , and at the same time, the insulating layer 112 can reduce the negative impact on the energy density of the battery cell 100 .

[0159] This embodiment further provides some thickness ranges of the insulating layer 112. On the premise that the insulating layer 112 can provide support for the pole ear portion 1112, this setting also limits the upper limit of the thickness of the insulating layer 112, so that the pole ear portion 1112 can have a certain bending ability to meet the requirements of electrical connection between the pole ear portion 1112 and the external structure, and can reduce the negative impact of the pole ear portion 1112 on the energy density of the battery cell 100; at the same time, this setting can also reduce the space occupied by the insulating layer 112, and reduce the negative impact of the insulating layer 112 on the energy density of the battery cell 100.

[0160] refer to Figures 6 to 9 In some embodiments, the main body 1111 includes two end surfaces 1111a at opposite ends along the width direction of the current collector 111, the main body 1111 also includes two side surfaces 1111b located on opposite sides along the thickness direction of the current collector 111, and the pole ear portion 1112 is formed on the end surface 1111a; the pole piece 11 also includes an active material layer 113 provided on the side surface 1111b, and the active material layer 113 covers at least a portion of the side surface 1111b; on the same projection plane perpendicular to the thickness direction of the current collector 111, the orthographic projection of the insulating layer 112 at least partially overlaps with the orthographic projection of the side surface 1111b.

[0161] The main body 1111 includes end faces 1111a and side faces 1111b. The end faces 1111a refer to the two surfaces of the main body 1111 located at opposite ends of the current collector 111 in the width direction Y. These are also the surfaces of the electrode 11 formed after die-cutting, and the electrode tabs 1112 are formed on the end faces 1111a. The side faces 1111b refer to the two surfaces of the main body 1111 located at opposite ends of the current collector 111 in the thickness direction Z. Active material is typically formed on the side faces 1111b.

[0162] The tab portion 1112 is formed on the end surface 1111 a , and extends from the end surface 1111 a of the main body 1111 in a direction away from the main body 1111 along the width direction Y of the current collector 111 .

[0163] The active material layer 113 refers to a layered structure formed on the side 1111b of the main body 1111 and used to participate in the electrochemical reaction. Depending on the polarity of the electrode 11, the material of the active material layer 113 may include lithium manganese oxide, lithium cobalt oxide, nickel cobalt lithium manganese oxide and other materials. The material of the active material layer 113 may also include natural graphite, artificial graphite and other materials.

[0164] The active material layer 113 can cover at least part of the corresponding side surface 1111b, that is, the active material layer 113 can only cover a part of the corresponding side surface 1111b, or can completely cover the entire corresponding side surface 1111b; because the area of ​​the active material layer 113 is positively correlated with the charge and discharge performance of the electrode 11, the active material layer 113 should cover the corresponding side surface 1111b as much as possible, that is, the active material layer 113 should cover most of the corresponding side surface 1111b or completely cover the corresponding side surface 1111b; and due to the influence of the processing technology, the active material layer 113 is usually not easy to completely cover the corresponding side surface 1111b, so when the active material layer 113 only covers a part of the corresponding side surface 1111b, the active material layer 113 should cover most of the area of ​​the corresponding side surface 1111b as much as possible, and make the area not covered by the active material layer 113 smaller.

[0165] The projection plane perpendicular to the thickness direction of the current collector 111 refers to a virtual plane perpendicular to the thickness direction of the current collector 111, and the virtual plane is also parallel to the current collector 111; the orthographic projection of the insulating layer 112 on the projection plane refers to the projection of the insulating layer 112 falling on the projection plane along the direction perpendicular to the projection plane, and is also the projection of the insulating layer 112 falling on the projection plane along the thickness direction Z of the current collector 111; the orthographic projection of the side surface 1111b on the projection plane refers to the projection of the side surface 1111b falling on the projection plane along the direction perpendicular to the projection plane, and is also the projection of the side surface 1111b falling on the projection plane along the thickness direction Z of the current collector 1111.

[0166] The orthographic projection of the insulating layer 112 at least partially overlaps with the orthographic projection of the side surface 1111 b , that is, the insulating layer 112 is connected to the main body 1111 and / or the active layer material layer in addition to being connected to the tab portion 1112 . For example, when the active material layer 113 completely covers the corresponding side surface 1111b, the insulating layer 112 can also be connected to the active material layer 113; for example, when the active material layer 113 only covers a portion of the corresponding side surface 1111b, the insulating layer 112 can be connected only to the side surface 1111b of the main body 1111; for example, when the active material layer 113 only covers a portion of the corresponding side surface 1111b, the insulating layer 112 can also be connected to the corresponding side surface 1111b and the active material layer 113 at the same time; for example, when the active material layer 113 only covers a portion of the corresponding side surface 1111b, the insulating layer 112 can also be connected only to the active material layer 113, and at this time, the portion of the side surface 1111b not covered by the active material layer 113 is not located on the side of the side surface 1111b close to the insulating layer 112.

[0167] Depending on the material of the insulating layer 112 , the insulating layer 112 may be connected to the side surface 1111 b and / or the active material layer 113 by bonding, curing or other methods.

[0168] In this embodiment, in addition to covering the pole ear portion 1112, the insulating layer 112 can also cover the side surface 1111b of the main body portion 1111 and / or a portion of the active material layer 113, so that in addition to providing support for the pole ear portion 1112, the insulating layer 112 can also improve the connection strength between the pole ear portion 1112 and the main body portion 1111, thereby making it difficult for the pole ear portion 1112 to tear at the connection portion between it and the main body portion 1111, further improving the safety performance and stability of the battery cell 100.

[0169] refer to Figures 6 to 9 In some embodiments, the insulating layer 112 includes two sub-insulating layers 1121 corresponding to the two side surfaces 1111b, the sub-insulating layer 1121 includes a first portion 1121a and a second portion 1121b connected to the first portion 1121a, the first portion 1121a covers at least part of the pole ear portion 1112; on the same projection plane perpendicular to the thickness direction of the current collector 111, the orthographic projection of the second portion 1121b overlaps with at least part of the orthographic projection of the side surface 1111b.

[0170] The sub-insulating layer 1121 refers to a part of the insulating layer 112. There are two sub-insulating layers 1121, and the two sub-insulating layers 1121 can be spliced ​​together to form the insulating layer 112. The two sub-insulating layers 1121 can be arranged on opposite sides of the current collector 111 and respectively cover the two side surfaces 1111b of the pole ear portion 1112, thereby improving the strength of the pole ear portion 1112.

[0171] The sub-insulating layer 1121 includes a first portion 1121a and a second portion 1121b. The first portion 1121a is a portion of the sub-insulating layer 1121 and covers at least a portion of the pole lug 1112. This means that the first portion 1121a is connected to the pole lug 1112, thereby increasing the strength of the pole lug 1112 and reducing its bending. Depending on the material of the sub-insulating layer 1121, the first portion 1121a can be bonded to the pole lug 1112 or connected to the pole lug 1112 by curing or other methods.

[0172] The projection plane perpendicular to the thickness direction of the current collector 111 refers to a virtual plane perpendicular to the thickness direction of the current collector 111, and the virtual plane is also parallel to the current collector 111; the second part 1121b is a part of the sub-insulating layer 1121, and the orthographic projection of the second part 1121b on the projection plane refers to the projection of the second part 1121b falling on the projection plane along the direction perpendicular to the projection plane, and is also the projection of the second part 1121b falling on the projection plane along the thickness direction Z of the current collector 111.

[0173] The orthographic projection of the second part 1121b overlaps at least partially with the orthographic projection of the side surface 1111b, that is, the second part 1121b is connected to the side surface 1111b and / or the active material layer 113. Depending on the coverage area and position of the active material layer 113, the second part 1121b can be connected only to the side surface 1111b or the active material layer 113, or can be connected to the side surface 1111b and the active material layer 113 at the same time; depending on the material of the sub-insulating layer 1121, the second part 1121b can be bonded to the side surface 1111b and / or the active material layer 113, or can be connected to the side surface 1111b and / or the active material layer 113 by curing or the like; the second part 1121b is connected to the first part 1121a, and the second part 1121b can be integrally formed with the first part 1121a, or can be connected to the first part 1121a by bonding, curing or the like.

[0174] It can be understood that because the first part 1121a is connected to the second part 1121b, and the second part 1121b is connected to the side 1111b and / or the active material layer 113, when the first part 1121a only covers part of the pole ear part 1112, the first part 1121a can at least cover the part where the pole ear part 1112 is connected to the first main body part 1111. At this time, the first part 1121a and the second part 1121b can play a role in improving the connection strength of the connection between the pole ear part 1112 and the main body part 1111.

[0175] This embodiment provides some specific structures of the insulating layer 112, so that the insulating layer 112 is formed by two sub-insulating layers 1121 connected to each other; the sub-insulating layer 1121 includes a first part 1121a and a second part 1121b, so that the first part 1121a covers at least part of the pole ear part 1112, and the second part 1121b covers part of the side surface 1111b, so that the insulating layer 112 can not only improve the strength of the pole ear part 1112, but also improve the connection strength between the pole ear part 1112 and the main body part 1111.

[0176] refer to Figure 6 、 Figure 8 In some embodiments where the active material layer 113 does not completely cover the corresponding side surface 1111b, the active material layer 113 covers a portion of the corresponding side surface 1111b, and forms a blank area 1111c on the side of the side surface 1111b close to the electrode ear portion 1112, and the second portion 1121b covers at least a portion of the blank area 1111c.

[0177] The blank area 1111c refers to the area on the side surface 1111b that is not covered by the active material layer 113. The blank area 1111c is formed on the side surface 1111b and is located on the side of the side surface 1111b close to the electrode ear portion 1112; Figure 8 The area corresponding to the size shown by L2 in the figure is the blank area 1111c.

[0178] The second portion 1121b covers at least part of the blank area 1111c, that is, the second portion 1121b can completely cover the blank area 1111c, or can only cover part of the blank area 1111c; for example, the second portion 1121b completely covers the blank area 1111c, and at this time, the end of the second portion 1121b away from the first portion 1121a contacts the active material layer 113.

[0179] The second portion 1121b covering the blank area 1111c can reduce the area of ​​direct contact between the first main body 1111 and the electrolyte, thereby reducing damage to the first main body 1111 by the electrolyte and reducing the occurrence of short circuits in the battery cell 100.

[0180] In this embodiment, the second portion 1121b can cover at least a portion of the blank area 1111c to protect the main body 1111. At the same time, it can also reduce the area of ​​the main body 1111 exposed to the outside, thereby reducing the occurrence of short circuits and other situations and improving the safety performance of the battery cell 100.

[0181] refer to Figure 6 、 Figure 8In some embodiments where the second portion 1121b covers the blank area 1111c, the sub-insulating layer 1121 further includes a third portion 1121c connected to the second portion 1121b on the opposite side of the first portion 1121a, the second portion 1121b covers the blank area 1111c, and the third portion 1121c covers a portion of the active material layer 113.

[0182] The third part 1121c is a part of the sub-insulating layer 1121, and the third part 1121c is connected to the side of the second part 1121b away from the first part 1121a, that is, the first part 1121a, the second part 1121b, and the third part 1121c are arranged in sequence along the width direction Y of the current collector 111; the third part 1121c can be integrally formed with the second part 1121b, and the third part 1121c can also be connected to the second part 1121b by bonding, curing, etc.

[0183] The third portion 1121c is connected to the active material layer 113 and covers a portion of the active material layer 113. Since the third portion 1121c is connected to the second portion 1121b, the second portion 1121b can completely cover the blank area 1111c at this time, so as to better protect the main body 1111 and better improve the safety performance of the battery cell 100.

[0184] According to the structure of the third portion 1121 c , the third portion 1121 c may be connected to the active material layer 113 by bonding, or by curing or other methods.

[0185] When the sub-insulating layer 1121 does not cover the active material layer 113, due to the influence of the processing technology, the second part 1121b of the sub-insulating layer 1121 is difficult to seal and contact the active material layer 113 without gaps, and the gap between the second part 1121b and the active material layer 113 can easily cause the main body 1111 to be exposed and cause short circuits and other situations.

[0186] Accordingly, in this embodiment, the sub-insulating layer 1121 further includes a third portion 1121 c , and the third portion 1121 c covers a portion of the active material layer 113 , so that the second portion 1121 b can completely cover the blank area 1111 c , thereby further improving the safety performance of the battery cell 100 .

[0187] refer to Figure 6 、 Figure 8 In some embodiments where the third portion 1121 c covers the active material layer 113 , on a projection plane perpendicular to the thickness direction of the current collector 111 , a size of an orthographic projection of the third portion 1121 c ranges from 0.1 mm to 1 mm.

[0188] The projection plane perpendicular to the thickness direction of the current collector 111 refers to a virtual plane perpendicular to the thickness direction of the current collector 111, and the virtual plane is also parallel to the current collector 111; the orthographic projection of the third part 1121c on the projection plane refers to the projection of the third part 1121c falling on the projection plane along the direction perpendicular to the projection plane, and is also the projection of the third part 1121c falling on the projection plane along the thickness direction Z of the current collector 111.

[0189] When the third portion 1121 c covers the active material layer 113 , the dimension of the orthographic projection of the third portion 1121 c on the projection plane in the width direction Y of the current collector 111 is the width of the third portion 1121 c . Figure 8 The size shown in L3 is the size of the orthographic projection of the third portion 1121c on the projection plane in the width direction Y of the current collector 111. The size can be 0.1mm, or 0.1mm, 0.2mm, 0.4mm, 0.55mm, 0.6mm, 0.8mm, 1mm or other values.

[0190] The width of the third part 1121c is positively correlated with the area of ​​the active material layer 113 covered by the third part 1121c. The larger the width of the third part 1121c, the larger the area of ​​the active material layer 113 covered by the third part 1121c, the better the stability of the third part 1121c connected to the active material layer 113, the less likely the third part 1121c is to fall off, and the less likely the blank area 1111c of the main body 1111 is to contact the electrolyte and cause damage. Because the charge and discharge capacity of the active material layer 113 is positively correlated with the area that it can contact with the electrolyte, the larger the width of the third part 1121c, the worse the charge and discharge capacity of the active material layer 113.

[0191] Therefore, the width of the third portion 1121 c is set to 0.1 mm to 1 mm, so that the third portion 1121 c can be stably connected to the active material layer 113 and the negative impact of the third portion 1121 c on the charge and discharge capacity of the active material layer 113 can be reduced.

[0192] For example, the size of the third part 1121c in the width direction Y of the current collector 111 on the orthographic projection of the projection plane can be 0.1 mm. On the premise that the third part 1121c can be connected to the active material layer 113, this setting can reduce the area of ​​the active material layer 113 covered by the third part 1121c, thereby reducing the negative impact of the third part 1121c on the charge and discharge capacity of the active material layer 113.

[0193] For example, the size of the third part 1121c in the width direction Y of the current collector 111 of the orthographic projection of the projection plane can be 0.55 mm. At this time, the third part 1121c can be more stably connected to the active material layer 113, so that the blank area 1111c is not easily contacted with the electrolyte; at the same time, this setting can also reduce the area of ​​the active material layer 113 covered by the third part 1121c.

[0194] For example, the size of the third part 1121c in the width direction Y of the current collector 111 can be 1 mm in the orthographic projection of the projection plane. At this time, the third part 1121c can be more stably connected to the active material layer 113, and the third part 1121c is not easy to detach under the infiltration of the electrolyte, so as to better improve the connection stability of the third part 1121c and reduce the risk of damage to the main body 1111 caused by the blank area 1111c contacting the electrolyte, thereby better protecting the main body 1111.

[0195] This embodiment provides some dimensions of the third part 1121c in the width direction Y of the current collector 111. On the premise that the third part 1121c can cover the active material layer 113, the dimension of the third part 1121c in the width direction Y of the current collector 111 is made smaller to reduce the negative impact of the third part 1121c on the charge and discharge capacity of the active material layer 113.

[0196] refer to Figure 6 、 Figure 9 In some embodiments where the active material layer 113 completely covers the corresponding side surface 1111 b , the active material layer 113 completely covers the corresponding side surface 1111 b , and the second portion 1121 b covers part of the active material layer 113 .

[0197] The active material layer 113 completely covers the corresponding side surface 1111b. At this time, the contact area between the active material layer 113 and the electrolyte is larger, and the charge and discharge performance of the active material layer 113 is better. At the same time, there is no blank area 1111c on the side surface 1111b, and the main body 1111 is not easily contacted with the electrolyte, thereby reducing the damage of the electrolyte to the main body 1111 and improving the service life of the main body 1111.

[0198] When the active material layer 113 completely covers the corresponding side surface 1111b, there is no blank area 1111c on the side surface 1111b. At this time, the sub-insulating layer 1121 can be directly connected to the active material layer 113, that is, the second portion 1121b covers part of the active material layer 113.

[0199] Because the first part 1121a is connected to the pole ear part 1112 and the second part 1121b is connected to the active material layer 113, the first part 1121a and the second part 1121b can also play a role in strengthening the connection strength between the pole ear part 1112 and the main body part 1111, thereby reducing the risk of tearing between the pole ear part 1112 and the main body part 1111.

[0200] In this embodiment, the active material layer 113 completely covers the side surface 1111b of the main body 1111, so that there is a larger contact area between the active material layer 113 and the electrolyte, thereby making the active material layer 113 have better charge and discharge capabilities; the second part 1121b covers part of the active material layer 113, so that the insulating layer 112 can not only improve the strength of the pole ear part 1112, but also improve the connection strength of the connection between the pole ear part 1112 and the main body 1111.

[0201] refer to Figure 6 、 Figure 9 In some embodiments where the active material layer 113 completely covers the corresponding side surface 1111 b , on a projection plane perpendicular to the thickness direction of the current collector 111 , a size of the orthographic projection of the second portion 1121 b ranges from 0.1 mm to 1 mm.

[0202] When the active material layer 113 completely covers the corresponding side surface 1111 b and the second portion 1121 b covers the active material layer 113 , the dimension of the orthographic projection of the second portion 1121 b on the projection plane in the width direction Y of the current collector 111 is the width of the second portion 1121 b . Figure 9 The size shown in L2 is the size of the orthographic projection of the second portion 1121b on the projection plane in the width direction Y of the current collector 111. The size can be 0.1mm, or 0.1mm, 0.2mm, 0.4mm, 0.55mm, 0.6mm, 0.8mm, 1mm or other values.

[0203] The width of the second part 1121b is positively correlated with the area of ​​the active material layer 113 covered by the second part 1121b. The larger the width of the second part 1121b, the larger the area of ​​the active material layer 113 covered by the second part 1121b, the better the stability of the second part 1121b connected to the active material layer 113, and the less likely the second part 1121b is to fall off. Because the charge and discharge capacity of the active material layer 113 is positively correlated with the area in which it can contact the electrolyte, the larger the width of the second part 1121b, the worse the charge and discharge capacity of the active material layer 113.

[0204] Therefore, the width of the second portion 1121 b is set to 0.1 mm to 1 mm, so that the second portion 1121 b can be stably connected to the active material layer 113 and the negative impact of the second portion 1121 b on the charge and discharge capacity of the active material layer 113 can be reduced.

[0205] For example, the size of the orthographic projection of the second part 1121b on the projection plane in the width direction Y of the current collector 111 can be 0.1 mm. On the premise that the second part 1121b can be connected to the active material layer 113, this setting can reduce the area of ​​the active material layer 113 covered by the second part 1121b, thereby reducing the negative impact of the second part 1121b on the charge and discharge capacity of the active material layer 113.

[0206] For example, the size of the second part 1121b in the width direction Y of the current collector 111 on the orthographic projection of the projection plane can be 0.55 mm. At this time, the second part 1121b can be more stably connected to the active material layer 113, so that the second part 1121b is not easy to fall off; at the same time, this setting can also reduce the area of ​​the active material layer 113 covered by the second part 1121b.

[0207] For example, the size of the second part 1121b in the width direction Y of the current collector 111 in the orthographic projection of the projection plane can be 1 mm. At this time, the second part 1121b can be more stably connected to the active material layer 113, and the second part 1121b is not easy to detach under the infiltration of the electrolyte, so as to better improve the connection stability of the second part 1121b, thereby better playing a role in improving the connection strength between the pole ear part 1112 and the main body part 1111.

[0208] This embodiment provides some dimensions of the second portion 1121b in the width direction Y of the current collector 111. On the premise that the second portion 1121b can be connected to the active material layer 113, the dimension of the second portion 1121b in the width direction Y of the current collector 111 is made smaller to reduce the negative impact of the second portion 1121b on the charge and discharge capacity of the active material layer 113.

[0209] In some embodiments, there are at least two electrode lugs 1112 that are spaced apart along the length direction of the current collector 111 ; there is one insulating layer 112 , and the insulating layer 112 covers at least one electrode lug 1112 .

[0210] The number of the pole ear portions 1112 is at least two, that is, the number of the pole ear portions 1112 can be two, or three or more; the pole ear portions 1112 are arranged at intervals along the length direction X of the current collector 111, so that after the pole piece 11 is wound, at least part of the pole ear portions 1112 can be stacked on each other.

[0211] The number of insulating layers 112 is one. When there are multiple pole ear portions 1112, the insulating layer 112 can only cover one or several of the multiple pole ear portions 1112 according to needs. Since the pole ear portions 1112 are arranged along the length direction X of the current collector 111, the size of the insulating layer 112 in the length direction X of the current collector 111 can be smaller at this time; the insulating layer 112 can also cover the pole ear portions 1112. At this time, the size of the insulating layer 112 in the length direction X of the current collector 111 is larger.

[0212] The insulating layer 112 has and covers at least one pole ear portion 1112, so that the insulating layer 112 can not only improve the strength of the pole ear portion 1112, but also reduce the difficulty of processing and setting the insulating layer 112; for example, during the processing, only one insulating layer 112 needs to be set on each pole ear portion 1112, and no other processing is required on the insulating layer 112.

[0213] In this embodiment, there is only one insulating layer 112 , and one insulating layer 112 can cover one or more pole ear portions 1112 , so that the insulating layer 112 can not only increase the strength of the pole ear portion 1112 and reduce the bending amplitude of the pole ear portion 1112 , but also reduce the difficulty of processing and setting the insulating layer 112 .

[0214] refer to Figure 6 、 Figure 8 、 Figure 10 In some embodiments, the insulating layer 112 includes a substrate layer 1121d and an adhesive layer 1121e disposed on the substrate layer 1121d . The adhesive layer 1121e is disposed on the side of the substrate layer 1121d facing the current collector 111 , and the adhesive layer 1121e is at least connected to the pole ear portion 1112 .

[0215] The substrate layer 1121d refers to a layered structure in the sub-insulating layer 1121 that is mainly used to provide a fixing basis. The substrate layer 1121d can be used to provide a fixing basis for the bonding layer 1121e, and can also improve the strength of the corresponding pole ear portion 1112, and can provide protection for the corresponding main body portion 1111 or the active material layer 113. According to the function of the substrate layer 1121d, the substrate layer 1121d should have a certain strength and a certain insulation ability. The material of the substrate layer 1121d may include plastic, rubber, ceramic, etc.

[0216] The bonding layer 1121e refers to the layered structure in the sub-insulating layer 1121 that mainly plays a fixing role. The bonding layer 1121e is arranged on the side of the substrate layer 1121d facing the current collector 111 to fix the substrate layer 1121d on the current collector 111. When the insulating layer 112 is only arranged on the pole ear portion 1112, the bonding layer 1121e is bonded to the pole ear portion 1112. When the insulating layer 112 also covers part of the side surface 1111b and / or part of the active material layer 113, the bonding layer 1121e is also bonded to the side surface 1111b and / or the active material layer 113; the material of the bonding layer 1121e may include rubber, resin or other materials; the bonding layer 1121e may be connected to the current collector 111 by photocuring, thermal curing or other curing methods.

[0217] When the sub-insulating layer 1121 is connected to the pole ear portion 1112, the adhesive bonding can bond the substrate layer 1121d to the pole ear portion 1112. At this time, the pressure on the pole ear portion 1112 can also be transmitted to the adhesive layer 1121e and the substrate layer 1121d, thereby improving the strength of the pole ear portion 1112 through the adhesive layer 1121e and the substrate layer 1121d.

[0218] This embodiment provides some structures of the sub-insulating layer 1121, so that the sub-insulating layer 1121 includes an adhesive layer 1121e and a substrate layer 1121d, so that the substrate layer 1121d can be connected to the pole ear portion 1112 through the adhesive layer 1121e, so that the substrate layer 1121d can provide support for the pole ear portion 1112 and improve the strength of the pole ear portion 1112, and the substrate layer 1121d can also play a role in protecting the pole ear portion 1112.

[0219] refer to Figure 5 In some embodiments, the battery cell 100 includes an electrode assembly 10 , the electrode assembly 10 includes a tab 13 , and the tab 13 includes at least two stacked tab portions 1112 .

[0220] The tab 13 refers to a structure in the electrode assembly 10 for conducting the electrode sheet 11 with a circuit outside the electrode assembly 10, and the tab 13 can be connected to the electrode terminal 40; the electrode assembly 10 can be formed by winding, stacking, etc. the electrode sheet 11; the electrode assembly 10 can include a positive electrode sheet, a separator 12 and a negative electrode sheet, and the positive electrode sheet, the separator 12, the negative electrode sheet and the separator 12 can be stacked in sequence.

[0221] The electrode tab 13 may include at least two stacked electrode tab portions 1112, that is, the electrode tab 13 may include only two electrode tab portions 1112, or may include three or more electrode tab portions 1112; because the electrode assembly 10 includes a wound or stacked electrode sheet 11, the stacking or winding of the electrode sheet 11 can enable at least part of the electrode tab portions 1112 arranged at intervals along its length direction X to be stacked, thereby forming a electrode tab portion 1112.

[0222] For example, the electrode assembly 10 can be formed by winding the electrode sheet 11. In this case, the positive electrode sheet, the separator 12, the negative electrode sheet, and the separator 12 are stacked to form a composite body, and the composite body is wound to form the electrode assembly 10. In this case, the winding of the electrode sheet 11 can enable at least part of the electrode ear portion 1112 on the other side to be stacked to form the electrode ear 13.

[0223] For example, the electrode assembly 10 can be formed by stacking pole pieces 11, in which case the positive pole pieces and the negative pole pieces are stacked alternately in sequence, and a diaphragm 12 is provided between two adjacent pole pieces 11; in this case, the length of each pole piece 11 can be set according to the size of the electrode assembly 10, and the pole ear portion 1112 on each pole piece 11 is also stacked with the pole piece 11 to form a pole ear 13.

[0224] When the tab 13 is connected to the electrode terminal 40, after the electrode assembly 10 is installed in the shell 20, the tab 13 gradually bends and deforms during the process of the end cover 30 being covered on the shell 20 and connected to the shell 20; because an insulating layer 112 is provided on each tab portion 1112, the overall strength of the tab 13 is improved, and the bending amplitude of the tab 13 is limited, and the tab 13 is not easy to be inserted between adjacent pole pieces 11 of the electrode assembly 10, thereby reducing the risk of short circuit between the tab 13 and the adjacent positive and negative pole pieces.

[0225] This embodiment provides a specific structure of the electrode tabs 13 of some electrode assemblies 10, so that the electrode tabs 13 include at least two stacked electrode tab portions 1112, and each electrode tab portion 1112 is provided with an insulating layer 112. At this time, the electrode tabs 13 of the electrode assembly 10 can have higher strength under the support of multiple insulating layers 112, thereby making it more difficult for the electrode tabs 13 to be inserted between the electrode sheets 11.

[0226] refer to Figure 2 、 Figure 3 In some embodiments, the battery cell 100 is a cylindrical battery cell 100 .

[0227] The battery cell 100 can be a cylindrical battery cell 100. In this case, the tab 13 of the electrode assembly 10 can be processed by a flattening method, that is, after the tab parts 1112 are stacked to form the tab 13, the tab 13 can be rotated and pressed using a flattening device through ultrasonic flattening, mechanical flattening or other methods to form a planar structure at one end of the electrode assembly 10.

[0228] During the process of flattening the tabs 13 , only a portion of each tab portion 1112 may be compressed and flattened, or the entire tab portion 1112 may be flattened.

[0229] During the process of flattening the pole ear 13, the pole ear 13 is continuously subjected to pressure. Since an insulating layer 112 is provided on each pole ear portion 1112, the overall strength of the pole ear 13 is improved. During the process of the pole ear 13 being continuously subjected to pressure, the bending amplitude of the pole ear 13 is limited, and the pole ear 13 is not easy to be inserted between the adjacent pole pieces 11 of the electrode assembly 10, thereby reducing the risk of short circuit between the pole ear 13 and the adjacent positive and negative pole pieces.

[0230] This embodiment provides some specific structures of the tabs 13 of the electrode assembly 10 , so that at least a portion of each tab portion 1112 is flattened to form the tab 13 , so that the electrode assembly 10 can adapt to the requirements of cylindrical battery cells 100 and the like.

[0231] refer to Figure 11 、 Figure 12 In other embodiments, the battery cell 100 may also be a square-shell battery cell.

[0232] In some embodiments, for the pasting process of the insulating layer 112, the pasting process of the insulating layer 112 can be set after the die-cutting process of the pole piece 11; for example, a patch module can be added to the die-cutting process to make the pole piece 11 run at a speed of 10 to 100 m / min and die-cut. After the pole piece 11 is die-cut, the die-cut pole piece 11 is continuously pasted by the patch module to bond the insulating layer 112 to the pole ear portion 1112.

[0233] In some embodiments, the positive electrode sheet is prepared as follows:

[0234] The active material layer 113 of the positive electrode sheet includes active material lithium iron phosphate (LiFePO4, LFP), binder polyvinylidene fluoride (PVDF) and conductive carbon black (Super P), which are uniformly mixed in a ratio of lithium iron phosphate: polyvinylidene fluoride: conductive carbon black = 95:3:2 to obtain a first mixed slurry.

[0235] The dispersion solvent is 1-methyl-2-pyrrolidone (NMP), and the first mixed slurry is dispersed using the dispersion solvent to obtain a positive electrode slurry.

[0236] The positive electrode slurry is coated on the two side surfaces 1111b of the aluminum foil (the current collector 111 of the positive electrode sheet), and is dried, rolled, die-cut and slit in sequence.

[0237] Insulating tape is used as the sub-insulating layer 1121 , and two insulating tapes are respectively attached to the pole ear portions 1112 on both sides of the aluminum foil to form the insulating layer 112 .

[0238] In some embodiments, the negative electrode sheet is prepared as follows:

[0239] The material of the active material layer 113 of the negative electrode sheet includes active material graphite, binder styrene butadiene rubber (SBR) and conductive carbon black, which are uniformly mixed in a ratio of graphite: styrene butadiene rubber: conductive carbon black = 94:4:2 to obtain a second mixed slurry.

[0240] The dispersion solvent is ionized water, and the second mixed slurry is dispersed using the dispersion solvent to obtain a negative electrode slurry.

[0241] The negative electrode slurry is coated on the two side surfaces 1111b of the copper foil (the current collector 111 of the negative electrode sheet), and is dried, rolled, die-cut and slit in sequence to obtain the negative electrode sheet.

[0242] In some embodiments, the base film of the separator 12 is polyethylene, and a 2 μm adhesive coating and a 1.5 μm PCS coating are sequentially coated on the base film, wherein the PCS coating is a polymer coating that may include polyvinylidene fluoride (PVDF).

[0243] In some embodiments, the electrolyte is a carbonate-based electrolyte, the solute of the electrolyte is lithium hexafluorophosphate (LFPF), and the solute concentration is 1 M (molar concentration).

[0244] In some embodiments, the electrode assembly 10 is prepared as follows:

[0245] The prepared positive electrode sheet, separator 12 and negative electrode sheet are wound and then hot pressed to obtain the electrode assembly 10.

[0246] In some embodiments, the assembly process of the battery cell 100 is as follows:

[0247] The anode sheet 11, the separator 12 and the cathode sheet 11 are stacked and wound in sequence to obtain the electrode assembly 10, wherein the anode sheet 11 is in the inner layer, and the anode sheet 11 is larger than the cathode sheet 11 in the length and width directions, and the length of the separator 12 exceeds the anode sheet 11; thereafter, the wound electrode assembly 10 is subjected to shaping, hot pressing, shelling, welding, baking, liquid injection, formation, aging and other processes in sequence to complete the assembly of the battery cell 100.

[0248] In some embodiments, the battery cell 100 includes a pole piece 11 , which includes a current collector 111 , an active material layer 113 , and an insulating layer 112 .

[0249] The current collector 111 includes a main body 1111 including two side surfaces 1111 b and two end surfaces 1111 a ; the current collector 1111 also includes a tab portion 1112 connected to the end surface 1111 a .

[0250] The active material layer 113 is provided on and covers the side surface 1111 b .

[0251] The insulating layer 112 is only connected to the pole ear portion 1112 and covers the opposite sides of the pole ear portion 1112. The insulating layer 112 is arranged at intervals in the length direction of the current collector 111, and the insulating layer 112 and the pole ear portion 1112 are arranged one-to-one; the size of the insulating layer 112 in the length direction X of the current collector 111 is the same as the size of the pole ear portion 1112 in the length direction X of the current collector 111; the size of the insulating layer 112 in the width direction Y of the current collector 111 is 1 / 3 of the size of the pole ear portion 1112 in the width direction Y of the current collector 111.

[0252] In a second aspect, some embodiments of the present application provide a battery device 1000, comprising the battery cell 100 provided by some embodiments of the first aspect; in the battery device 1000, the burrs of the pole piece 11 are unlikely to pierce the adjacent diaphragm 12 and cause a short circuit, thereby enabling the battery device 1000 to have higher stability.

[0253] In a third aspect, some embodiments of the present application further provide an energy storage device 1 , comprising the battery cell 100 provided by some embodiments of the first aspect, or the battery device 1000 provided by some embodiments of the second aspect.

[0254] Energy storage device 1 includes one or more battery clusters to increase the voltage and capacity of energy storage device 1. A battery cluster may include multiple battery devices 1000, which are connected in series via a busbar to increase the voltage of energy storage device 1. When energy storage device 1 includes multiple battery clusters, the battery clusters are connected in parallel to increase the capacity of energy storage device 1.

[0255] The energy storage device 1 can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. The energy storage device 1 can store electrical energy as needed and output it at the appropriate time. For example, the energy storage device 1 can store electrical energy during low-power periods and provide electrical energy to relevant users or electrical equipment during peak power periods. The energy storage system provided in the embodiments of the present application can be any power system that requires the energy storage device 1.

[0256] In some embodiments, the energy storage device 1 is an energy storage container or an energy storage cabinet.

[0257] In some embodiments, the energy storage device 1 may include a cabinet and one or more battery clusters, where the battery clusters are housed in the cabinet.

[0258] In some embodiments, the energy storage device 1 may include modules such as a thermal management module, a main control module, a master control module, a power distribution module, and a fire protection module.

[0259] As an example, the thermal management module may include a liquid cooling unit that provides cooling liquid for regulating the temperature of the battery cells 100 to each battery device 1000 through a pipeline.

[0260] For example, the master control module can serve as the battery management unit (BMU) of a battery cluster, monitoring and managing the cluster. The master control module can monitor information such as the battery cluster's current, voltage, power, or temperature. For example, it can control the battery cluster's charge and discharge current and voltage. The master control module includes modules such as the slave battery management unit (SBMU) and the fusion switch.

[0261] As an example, the master control module can serve as the battery management unit of the energy storage device 1, used to monitor and manage the energy storage device 1. The master control module can monitor information such as the current, voltage, power, state of charge, or temperature of the energy storage device 1. For example, it can control the charge and discharge current and voltage of the energy storage device 1. As an example, the master control module includes modules such as an insulation monitoring module (IMM), a master battery management unit (MBMU), an Ethernet (ETH), and a fiber optic conversion module.

[0262] As an example, the fire protection module includes a control panel, detectors, alarm devices, etc., which are used to detect, alarm or extinguish fires in the energy storage system.

[0263] As an example, the power distribution module can be used to distribute power to modules in the energy storage device 1 that require power.

[0264] Fourthly, reference Figure 13 Some embodiments of the present application also provide an energy storage system, including a power conversion device 2 and an energy storage device 1 provided in some embodiments of the third aspect, wherein the power conversion device 2 is used to electrically connect the power generation device 3 and the energy storage device 1.

[0265] The energy storage system may include one or more energy storage devices 1 and a power converter system 2 (PCS). The power converter system 2 is connected between the power generation device 3 and the energy storage device 1. The power generation device 3 is used to generate electrical energy, and the electrical energy generated by the power generation device 3 can be stored in the energy storage device 1 through the power converter system 2. As an example, the power generation device 3 may be a solar panel, a hydropower generation device, a thermal power generation device, a wind power generation device, etc. The specific type of the power generation device 3 is not limited in this application.

[0266] In a fifth aspect, some examples of the present application further provide an electrical device, comprising the battery cell 100 provided in some embodiments of the first aspect, or the battery device 1000 provided in some embodiments of the second aspect; or the energy storage device 1 provided in some embodiments of the third aspect, or the energy storage system provided in some embodiments of the fourth aspect. The battery cell 100 or the battery device 1000 is used to store or provide electrical energy.

[0267] Sixth aspect, reference Figure 14 Some embodiments of the present application further provide a charging network, comprising a charging pile 4 and the energy storage device 1 provided in some embodiments of the third aspect, or the energy storage system provided in some embodiments of the fourth aspect. The energy storage device 1 or the energy storage system is used to provide electrical energy to the charging pile 4.

[0268] Charging station 4 is electrically connected to energy storage device 1, which is used to provide electrical energy to charging station 4. Charging station 4 is electrically connected to battery device 1000 in energy storage device 1 via a cable, and battery device 1000 can provide its stored electrical energy to charging station 4. Charging station 4 has one or more connectors 5, which are used to connect to electrical equipment (such as vehicles) to replenish energy to the electrical equipment.

[0269] The energy storage device 1 can be located inside the charging pile 4 (for example, an integrated storage and charging device), or outside the charging pile 4 .

[0270] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: The invention comprises a pole piece, wherein the pole piece comprises: a current collector, the current collector comprising a main body and a tab portion connected to the main body, the tab portion extending from one side of the main body along a width direction of the current collector in a direction away from the main body; An insulating layer is provided on the pole ear portion and covers at least a portion of the pole ear portion, wherein the insulating layer is located on a side of the pole ear portion close to the main body portion.

2. The battery cell according to claim 1, wherein: There are at least two pole lugs, which are spaced apart along the length direction of the current collector; There are at least two insulating layers, which are arranged corresponding to the pole lugs, and the insulating layers are arranged at intervals along the length direction of the current collector.

3. The battery cell according to claim 1 or 2, characterized in that: In the length direction of the current collector, the size of the insulating layer is smaller than or equal to the size of the electrode lug portion.

4. The battery cell according to any one of claims 1 to 3, characterized in that: On the same projection plane perpendicular to the thickness direction of the current collector, the orthographic projection of the insulating layer and the orthographic projection of the pole ear portion at least partially overlap, and the ratio of the orthographic projection of the insulating layer to the orthographic projection of the pole ear portion in the width direction of the current collector is less than or equal to 1:

3.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The yield strength of the insulating layer is greater than or equal to 25 MPa.

6. The battery cell according to claim 5, characterized in that The yield strength of the insulating layer is less than or equal to 100 MPa.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The thickness of the insulating layer is greater than or equal to 9 μm.

8. The battery cell according to any one of claims 1 to 6, characterized in that: The thickness of the insulating layer ranges from 9 μm to 30 μm.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The main body includes two end surfaces at opposite ends along the width direction of the current collector, and the main body also includes two side surfaces located at opposite sides along the thickness direction of the current collector, and the pole ear portion is formed on the end surfaces; The electrode further includes an active material layer provided on the side surface, wherein the active material layer covers at least a portion of the side surface; On the same projection plane perpendicular to the thickness direction of the current collector, the orthographic projection of the insulating layer and the orthographic projection of the side surface at least partially overlap.

10. The battery cell according to claim 9, characterized in that The insulating layer includes two sub-insulating layers corresponding to the two side surfaces, the sub-insulating layer includes a first portion and a second portion connected to the first portion, and the first portion covers at least a portion of the electrode tab portion; On the same projection plane perpendicular to the thickness direction of the current collector, an orthographic projection of the second portion at least partially overlaps with an orthographic projection of the side surface.

11. The battery cell according to claim 10, characterized in that The active material layer covers a portion of the corresponding side surface and forms a blank area on a side of the side surface close to the electrode ear portion, and the second portion covers at least a portion of the blank area.

12. The battery cell according to claim 11, characterized in that The sub-insulating layer further includes a third portion connected to a side of the second portion opposite to the first portion, the second portion covers the blank area, and the third portion covers a portion of the active material layer.

13. The battery cell according to claim 12, characterized in that On a projection plane perpendicular to the thickness direction of the current collector, a size range of a projection of the third portion on the corresponding side surface is 0.1 mm to 1 mm.

14. The battery cell according to claim 10, characterized in that The active material layer completely covers the corresponding side surface, and the second portion covers a portion of the active material layer.

15. The battery cell according to claim 14, characterized in that On a projection plane perpendicular to the thickness direction of the current collector, a size of a projection of the second portion on the corresponding side surface ranges from 0.1 mm to 1 mm.

16. The battery cell according to claim 1, characterized in that There are at least two pole lugs, which are spaced apart along the length direction of the current collector; There is one insulating layer, and the insulating layer covers at least one of the pole lugs.

17. The battery cell according to any one of claims 1 to 16, characterized in that: The insulating layer includes a base material layer and an adhesive layer provided on the base material layer. The adhesive layer is provided on a side of the base material layer facing the current collector, and the adhesive layer is at least connected to the electrode tab portion.

18. The battery cell according to any one of claims 1 to 17, characterized in that: The battery cell includes an electrode assembly, the electrode assembly includes a tab, and the tab includes at least two stacked tab portions.

19. The battery cell according to any one of claims 1 to 18, characterized in that: The battery cell is a cylindrical battery cell.

20. A battery device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 19.

21. An energy storage device, characterized in that: comprising a plurality of battery cells according to any one of claims 1 to 19, or a plurality of battery devices according to claim 20; The battery cell or the battery device is used to store or provide electrical energy.

22. An energy storage system, characterized in that: It comprises a power conversion device and the energy storage device as claimed in claim 21, wherein the power conversion device is used to electrically connect the power generation device and the energy storage device.

23. An electrical device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 19, the battery device according to claim 20, the energy storage device according to claim 21 or the energy storage system according to claim 22, wherein the battery cell is used to store or provide electrical energy.

24. A charging network, characterized in that: comprising a charging pile and the energy storage device according to claim 21, or the energy storage system according to claim 22; The energy storage device or the energy storage system is used to provide electrical energy to the charging pile.

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