Battery cells, battery packs, electrical devices and energy storage devices

Abstract

This application provides a battery cell, a battery device, a power consumption device, and an energy storage device, belonging to the field of battery technology. The battery cell includes: a first separator, a first electrode, a second separator, and a second electrode. The first separator, first electrode, second separator, and second electrode are sequentially stacked and wound to form an electrode assembly. The battery cell also includes: a first adhesive layer, at least partially located between the outermost ring of the first electrode and the first separator adjacent to the outermost ring of the first electrode to connect the first separator and the first electrode; and a second adhesive layer, at least partially located between the outermost ring of the second electrode and the second separator adjacent to the outermost ring of the second electrode to connect the second separator and the second electrode. The wound ends of the first and second separators are also fixed to the outer surface of the electrode assembly. This application provides a battery cell with a first adhesive layer and a second adhesive layer to reduce the relative sliding between the outermost first electrode and the second electrode, thus improving the lithium plating problem.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, power supply device, and energy storage device. Background Technology

[0002] Energy conservation and emission reduction are key to sustainable social development. Rechargeable batteries, with their ability to store and release energy as needed, are widely used in various electrical devices and energy storage systems, and are an important component in promoting energy transition and sustainable development. For the new energy industry, battery technology is a crucial factor in its development.

[0003] During the charging and discharging process, lithium plating may occur in individual battery cells. In severe cases, the deposited lithium can puncture the separator, causing an internal short circuit between the cathode and anode plates, resulting in a safety failure risk. Utility Model Content

[0004] This application aims to at least address one of the technical problems existing in the background art. Therefore, one object of this application is to provide a battery cell, battery device, power consumption device, and energy storage device to improve the problem of lithium plating that may occur in battery cells during charging and discharging.

[0005] An embodiment of the first aspect of this application provides a battery cell, including: a first separator, a first electrode, a second separator, and a second electrode, wherein the first separator, the first electrode, the second separator, and the second electrode are sequentially stacked and wound to form an electrode assembly; the battery cell further includes: a first adhesive layer, at least partially located between the outermost ring of the first electrode and the first separator adjacent to the outermost ring of the first electrode to connect the first separator and the first electrode; a second adhesive layer, at least partially located between the outermost ring of the second electrode and the second separator adjacent to the outermost ring of the second electrode to connect the second separator and the second electrode, wherein the winding ends of the first separator and the second separator are also fixed to the outer surface of the electrode assembly.

[0006] In the technical solution of this application embodiment, the outermost ring of the first electrode is connected to the first separator adjacent to the outermost ring of the first electrode through a first adhesive layer, thereby fixing the position between them. The outermost ring of the second electrode is connected to the second separator adjacent to the outermost ring of the second electrode through a second adhesive layer, thereby fixing the position between them. Since the winding ends of the first and second separators are fixed to the outer surface of the electrode assembly, the positions of the first separator adjacent to the outermost ring of the first electrode and the second separator adjacent to the outermost ring of the second electrode are fixed. This fixes the positions of the first electrode fixed to the first separator and the second electrode fixed to the second separator, reducing the risk of relative sliding between the outermost rings of the first and second electrodes during the charging and discharging process of the electrode assembly. It also keeps the gap between the first and second electrodes small, resulting in a shorter lithium-ion migration path between them. This solves the problem of lithium-ion deposition caused by a long lithium-ion migration path between the first and second electrodes.

[0007] In some embodiments, the outermost ring of the first separator is positioned further away from the winding center of the electrode assembly than the outermost ring of the second separator. Thus, the first separator is located on the outermost side of the electrode assembly, and the first adhesive layer is located on the side of the outermost first electrode that is away from the outermost second electrode, rather than between the first and second electrodes. This avoids the problem of the first adhesive layer hindering lithium-ion transport due to its location between the first and second electrodes, and helps maintain the normal charge and discharge performance of the electrode assembly.

[0008] In some embodiments, the outermost ring of the second electrode is divided into a first segment and a second segment adjacent to each other along the winding direction of the electrode assembly. The winding end of the second electrode is located in the second segment, which extends beyond the winding end of the first electrode along the winding direction of the electrode assembly. A second adhesive layer connects the second segment and the second separator. Thus, the second adhesive layer is located between the second segment and the second separator, ensuring that it is not located between the outermost rings of the first and second electrodes. This prevents obstruction of lithium-ion transport between the first and second electrodes, thus facilitating the maintenance of normal charge-discharge performance of the electrode assembly.

[0009] In some embodiments, the outermost ring of the first electrode is divided into a third segment and a fourth segment adjacent to each other along the winding direction of the electrode assembly. The third segment is located on the side of the second segment near the winding center of the electrode assembly and faces the second segment across a first separator. The fourth segment is located on the side of the first segment away from the winding center of the electrode assembly and faces the first segment across a second separator. A first adhesive layer connects the fourth segment and the first separator. This ensures that the first adhesive layer is not located between the outermost first electrode and the outermost second electrode, thus not hindering lithium-ion transport between the first and second electrodes and helping to maintain the normal charge and discharge performance of the electrode assembly.

[0010] In some embodiments, along the winding direction of the electrode assembly, the length of the first adhesive layer connecting the fourth segment and the first diaphragm is greater than or equal to 5 mm. This ensures that the length of the first adhesive layer is sufficient to provide good adhesion between the first electrode and the first diaphragm, thereby allowing the outermost ring of the first electrode to be more securely fixed to the first diaphragm.

[0011] In some embodiments, the second adhesive layer includes a first extension that extends beyond the winding end of the second electrode sheet along the winding direction of the electrode assembly. The first extension faces at least a portion of the fourth segment of the first electrode sheet across the first separator and is bonded to the first separator. Thus, the second electrode sheet is connected to both the first and second separators via the second adhesive layer, enhancing the stability of the second electrode sheet and further reducing the risk of movement under the expansion force of the electrode assembly, thereby further reducing the risk of relative slippage between the first and second electrodes. Simultaneously, the first extension is bonded to the first separator outside the fourth segment, and no second electrode sheet is disposed outside the fourth segment. Therefore, the first extension is not located between the first and second electrodes, and thus does not affect lithium-ion transport between the first and second electrodes.

[0012] In some embodiments, the electrode assembly includes a straight portion and a bent portion, with a second adhesive layer located at the bent portion. Positioning the second adhesive layer at the bent portion does not increase the overall thickness of the electrode assembly in the direction perpendicular to the straight portion, thus maintaining the thinness and lightness of the electrode assembly and improving the energy density and space utilization of the battery cell.

[0013] In some embodiments, the length of the first extension along the winding direction of the electrode assembly is greater than or equal to 5 mm. This ensures that the length of the first extension is sufficient to provide good adhesion between the second electrode and the first diaphragm, thereby fixing the outermost ring of the second electrode firmly and securely to the first diaphragm, preventing slippage under the expansion force of the electrode assembly.

[0014] In some embodiments, along the winding direction of the electrode assembly, the winding end of the second diaphragm extends beyond the winding end of the first electrode. The first adhesive layer includes a second extension that extends beyond the winding end of the first electrode along the winding direction of the electrode assembly. The second extension is bonded to the second diaphragm that extends beyond the winding end of the first electrode. By providing the second extension, the first electrode and the second electrode are respectively connected to opposite surfaces of the same second diaphragm. Therefore, both the first electrode and the second electrode are fixed to the same second diaphragm, further reducing the risk of relative slippage between the first electrode and the second electrode.

[0015] In some embodiments, the thickness of the first adhesive layer is greater than or equal to 3 μm and less than or equal to 50 μm. Setting the first adhesive layer within this thickness range ensures that it provides good adhesion while preventing excessive thickness. This helps to avoid localized compression of the electrode assembly due to an excessively thick first adhesive layer, thus maintaining the structural integrity of the electrode assembly.

[0016] In some embodiments, the thickness of the second adhesive layer is greater than or equal to 3 μm and less than or equal to 50 μm. Setting the second adhesive layer within this thickness range ensures that it provides good adhesion while preventing excessive thickness. This helps to avoid localized compression of the electrode assembly due to an excessively thick second adhesive layer, thus maintaining the structural integrity of the electrode assembly.

[0017] In some embodiments, along the winding axis of the electrode assembly, the ratio of the width of the first adhesive layer to the width of the first electrode sheet is greater than or equal to 0.5 and less than or equal to 1. Setting the ratio of the width of the first adhesive layer to the width of the first electrode sheet within this range results in a larger bonding area of ​​the first adhesive layer on the first electrode sheet, which can play a better role in fixing the first electrode sheet and effectively reduce the risk of relative slippage between the first electrode sheet and the second electrode sheet.

[0018] In some embodiments, along the winding axis of the electrode assembly, the ratio of the width of the second adhesive layer to the width of the second electrode sheet is greater than 0.5 and less than or equal to 1. Setting the ratio of the width of the second adhesive layer to the width of the second electrode sheet within this range results in a larger bonding area of ​​the second adhesive layer on the second electrode sheet, which can better fix the second electrode sheet and effectively reduce the risk of relative slippage between the first electrode sheet and the second electrode sheet.

[0019] An embodiment of the second aspect of this application provides a battery device that includes the battery cell described in the above embodiments.

[0020] An embodiment of the third aspect of this application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0021] An embodiment of the fourth aspect of this application provides an energy storage device, which includes the battery device in the above embodiments, the battery device being used to store electrical energy.

[0022] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0023] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0024] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0025] Figure 2 This is an exploded structural diagram of a battery according to some embodiments of this application;

[0026] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0027] Figure 4 This is one of the schematic diagrams of the end face structure of the electrode assembly in some embodiments of this application;

[0028] Figure 5 This is a second schematic diagram of the end face structure of the electrode assembly in some embodiments of this application;

[0029] Figure 6 This is a top view of the first electrode and the first adhesive layer in a flat state according to some embodiments of this application;

[0030] Figure 7 This is a top view of the second electrode and the second adhesive layer in a flat state according to some embodiments of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1000 vehicles;

[0033] Battery 100, first separator 101, first electrode 102, second separator 103, second electrode 104, first adhesive layer 105, second adhesive layer 106;

[0034] Controller 200;

[0035] Motor 300;

[0036] Box 10, Part 11, Part 2 12;

[0037] Battery cell 20, end cap 21, electrode terminal 21a, housing 22, electrode assembly 23, tab 23a;

[0038] First extension 31, first body 32;

[0039] Second extension 41, second body 42;

[0040] First paragraph 1, second paragraph 2, third paragraph 3, fourth paragraph 4;

[0041] Winding direction r;

[0042] The width of the first adhesive layer is W1, the width of the first electrode is W2, the width of the second adhesive layer is W3, and the width of the second electrode is W4. Detailed Implementation

[0043] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0045] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0048] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0049] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0050] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0051] During charging and discharging, the electrode assembly expands and contracts. The outermost cathode and anode plates are prone to relative sliding under the influence of expansion forces. When the electrode assembly contracts, the gap between the outermost cathode and anode plates increases, thus lengthening the lithium-ion migration path and increasing impedance. In this situation, lithium ions released from the cathode cannot quickly reach the anode plate to embed within it. Consequently, some lithium ions gain electrons on the anode surface, forming elemental lithium, which is deposited as metallic lithium, resulting in lithium plating on the anode plate.

[0052] Based on the above considerations, in order to solve the problem of lithium plating that may occur in battery cells during charging and discharging, a battery cell is designed. By setting a first adhesive layer and a second adhesive layer, at least a portion of the first adhesive layer is located between the outermost ring of the first electrode and the first separator adjacent to the outermost ring of the first electrode to connect the first separator and the first electrode. At least a portion of the second adhesive layer is located between the outermost ring of the second electrode and the second separator adjacent to the outermost ring of the second electrode to connect the second separator and the second electrode. The winding ends of the first separator and the second separator are also fixed to the outer surface of the electrode assembly.

[0053] In this type of battery cell, the outermost ring of the first electrode is connected to the first separator adjacent to the outermost ring of the first electrode through a first adhesive layer, thus fixing their relative positions. Similarly, the outermost ring of the second electrode is connected to the second separator adjacent to the outermost ring of the second electrode through a second adhesive layer, also fixing their relative positions. Since the winding ends of the first and second separators are fixed to the outer surface of the electrode assembly, the positions of the first separator adjacent to the outermost ring of the first electrode and the second separator adjacent to the outermost ring of the second electrode are fixed. This fixes the positions of the first electrode fixed to the first separator and the second electrode fixed to the second separator, reducing the risk of relative slippage between the outermost rings of the first and second electrodes during charging and discharging of the electrode assembly. It also keeps the gap between the first and second electrodes small, resulting in a shorter lithium-ion migration path between them. This solves the problem of lithium-ion deposition caused by a long lithium-ion migration path between the first and second electrodes.

[0054] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices or energy storage devices such as vehicles, ships, or aircraft. A power system comprising the electrical device or energy storage device can be constructed using the battery cells and batteries disclosed in this application. This helps to improve the problem of lithium plating in battery cells and enhances the stability of battery performance and battery life.

[0055] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0056] This application also provides an energy storage device that uses a battery as a power source. The energy storage device can be, but is not limited to, an energy storage container, an energy storage cabinet, an energy storage power station, an energy storage battery pack, or a portable energy storage system.

[0057] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0058] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0059] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0060] Please refer to Figure 2 , Figure 2 This is an exploded structural diagram of a battery provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20, and the housing 10 can employ various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, and together define a space for accommodating the battery cell 20.

[0061] In battery 100, there can be multiple battery cells 20, which can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel. Battery 100 may also include other structures, such as a busbar component for electrical connection between multiple battery cells 20.

[0062] refer to Figures 3 to 5This application provides a battery cell comprising: a first separator 101, a first electrode 102, a second separator 103, and a second electrode 104. The first separator 101, the first electrode 102, the second separator 103, and the second electrode 104 are sequentially stacked and wound to form an electrode assembly. The battery cell further comprises: a first adhesive layer 105, at least partially located between the outermost ring of the first electrode 102 and the first separator 101 adjacent to the outermost ring of the first electrode 102 to connect the first separator 101 and the first electrode 102. The battery cell further comprises: a second adhesive layer 106, at least partially located between the outermost ring of the second electrode 104 and the second separator 103 adjacent to the outermost ring of the second electrode 104 to connect the second separator 103 and the second electrode 104. The winding ends of the first separator 101 and the second separator 103 are also fixed to the outer surface of the electrode assembly.

[0063] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical or flat.

[0064] Please refer to Figure 3 , Figure 3 This is an exploded structural diagram of a battery cell provided in some embodiments of this application. The battery cell 20 refers to the smallest unit that makes up the battery. For example... Figure 3 The battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23, and other functional components.

[0065] End cap 21 refers to a component that covers the opening of housing 22 to isolate the internal environment of the battery cell from the external environment. The shape of end cap 21 may be adapted to fit the shape of housing 22. Functional components such as electrode terminals 21a may be provided on end cap 21. Electrode terminals 21a can be used for electrical connection with electrode assembly 23 to output or input electrical energy to the battery cell. In some embodiments, end cap 21 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell reaches a threshold. In some embodiments, an insulating member may also be provided inside end cap 21 to isolate the electrical connection components within housing 22 from end cap 21, thereby reducing the risk of short circuits.

[0066] The housing 22 is an assembly used to cooperate with the end cap 21 to form the internal environment of the battery cell, wherein the formed internal environment can be used to accommodate the electrode assembly 23, electrolyte and other components.

[0067] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The portions of the first electrode 102 and the second electrode 104 containing active material constitute the main body of the electrode assembly, while the portions of the first electrode 102 and the second electrode 104 without active material each constitute tabs 23a. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 23a connect to the electrode terminals to form a current loop.

[0068] In some embodiments, the first electrode 102 and the second electrode 104 may be spirally wound so that the formed wound body has a spiral structure.

[0069] In other embodiments, the electrode assembly may also include a straight portion and bent portions located at both ends of the straight portion, wherein the first electrode 102 and the second electrode 104 of the straight portion are parallel to each other.

[0070] The first electrode 102 can be a cathode and the second electrode 104 can be an anode; or the first electrode 102 can be an anode and the second electrode 104 can be a cathode.

[0071] The first electrode 102 may include a first current collector and a first active material layer, the first active material layer being located on two opposite surfaces of the first electrode 102. The material of the first current collector may include, but is not limited to, aluminum foil, copper foil, carbon nanotube film, metal / carbon composite current collector, etc. The constituent materials of the first active material layer include, but are not limited to, lithium cobalt oxide, lithium iron phosphate, ternary materials, etc.

[0072] The second electrode 104 may include a second current collector and a second active material layer, the second active material layer being located on two opposite surfaces of the second electrode 104. The material of the second current collector includes, but is not limited to, copper foil, nickel foil, carbon materials, copper / carbon composite current collectors, etc. The constituent materials of the second active material layer include, but are not limited to, graphite, silicon-carbon composite materials, lithium titanate, etc.

[0073] This application does not impose any particular limitation on the types of the first diaphragm 101 and the second diaphragm 102. Porous membranes with good chemical and mechanical stability, which are well known to those skilled in the art, can be selected. In some embodiments, the materials of the first diaphragm 101 and the second diaphragm 102 include, but are not limited to, at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, alumina, silica, polyester, polyamide, lithium lanthanum zirconium oxide, etc.

[0074] The first diaphragm 101, the first electrode 102, the second diaphragm 103, and the second electrode 104 are sequentially stacked and wound to form an electrode assembly, such that the electrode assembly is arranged in the order of one turn of the first diaphragm 101, one turn of the first electrode 102, one turn of the second diaphragm 103, and one turn of the second electrode 104. The first diaphragm 101 may be located at the outermost ring of the entire electrode assembly, or the second diaphragm 103 may be located at the outermost ring of the entire electrode assembly.

[0075] Along the winding direction of the electrode assembly, the winding ends of the first diaphragm 101 and the second diaphragm 103 may extend beyond the winding ends of the first electrode 102 and the second electrode 104. The first diaphragm 101 extending beyond the winding end of the first electrode 102 and the second diaphragm 103 extending beyond the winding end of the second electrode 104 are considered "empty-wound diaphragms." An empty-wound diaphragm refers to the portion of the diaphragm that is wound separately during the electrode assembly manufacturing process without being superimposed on other components such as electrodes. The winding ends of the first diaphragm 101 and the second diaphragm 103 may be aligned or misaligned. The winding ends of the first diaphragm 101 and the second diaphragm 103 can be adhered to the outer surface of the electrode assembly using adhesive tape. Understandably, when the first diaphragm 101 is located at the outermost edge of the entire electrode assembly, the outer surface of the electrode assembly can be the first diaphragm 101, and the winding end of the first diaphragm 101 can be attached to the starting position of the outermost first diaphragm 101. Similarly, when the second diaphragm 103 is located at the outermost edge of the entire electrode assembly, the outer surface of the electrode assembly can be the second diaphragm 103, and the winding end of the second diaphragm 103 can be attached to the starting position of the outermost second diaphragm 103. The winding end of the first diaphragm 101 can be attached to the surface of the outermost second diaphragm 103.

[0076] The outermost ring of the first electrode 102 ends at the winding end of the first electrode 102, which is also the cut-off point of the first electrode 102. The starting position of the outermost ring of the first electrode 102 is flush with the ending position of the first electrode 102; in other words, the outermost ring of the first electrode 102 is the outermost portion of the multiple turns of the first electrode 102. Similarly, the outermost ring of the second electrode 104 ends at the winding end of the second electrode 104, which is also the cut-off point of the second electrode 104. The starting position of the outermost ring of the second electrode 104 is flush with the ending position of the second electrode 104; in other words, the outermost ring of the second electrode 104 is the outermost portion of the multiple turns of the second electrode 104.

[0077] Figure 4 and Figure 5As an example, the first adhesive layer shown is located near the winding end of the first electrode, and the second adhesive layer is located near the winding end of the second electrode. In practice, the first adhesive layer 105 can be located anywhere between the outermost ring of the first electrode 102 and the first diaphragm 101 adjacent to the outermost ring of the first electrode 102, and the second adhesive layer 106 can be located anywhere between the outermost ring of the second electrode 104 and the second diaphragm 103 adjacent to the outermost ring of the second electrode 104. Exemplarily, as... Figure 4 as well as Figure 5 As shown, when the first diaphragm 101 is located at the outermost edge of the entire electrode assembly, the first diaphragm 101 adjacent to the outermost edge of the first electrode 102 is located outside the outermost edge of the first electrode 102, and the second diaphragm 103 adjacent to the outermost edge of the second electrode 104 is located outside the outermost edge of the second electrode 104.

[0078] refer to Figure 4 The first adhesive layer 105 can be entirely located between the outermost ring of the first electrode 102 and the first diaphragm 101 adjacent to the outermost ring of the first electrode 102; Reference Figure 5 The first adhesive layer 105 may also be partially located between the outermost ring of the first electrode 102 and the first diaphragm 101 adjacent to the outermost ring of the first electrode 102, with the remaining portion extending out of the winding end of the first electrode 102.

[0079] refer to Figure 4 The second adhesive layer 106 can be entirely located between the outermost ring of the second electrode 104 and the second diaphragm 103 adjacent to the outermost ring of the second electrode 104; Reference Figure 5 The second adhesive layer 106 may also be partially located between the outermost ring of the second electrode 104 and the second diaphragm 103 adjacent to the outermost ring of the second electrode 104, with the remaining portion extending out of the winding end of the second electrode 104.

[0080] The material of the first adhesive layer 105 includes, but is not limited to, hot melt adhesive, pressure-sensitive adhesive, UV-curable adhesive, double-sided adhesive, etc. For example, taking hot melt adhesive as an example, the material of the first adhesive layer 105 may include polymers such as ethylene-vinyl acetate copolymer, polyamide, polyolefin, and polyurethane.

[0081] The material of the second adhesive layer 106 includes, but is not limited to, hot melt adhesive, pressure-sensitive adhesive, UV-curable adhesive, double-sided adhesive, etc. For example, taking hot melt adhesive as an example, the material of the second adhesive layer 106 may include polymers such as ethylene-vinyl acetate copolymer, polyamide, polyolefin, and polyurethane.

[0082] In some embodiments, the first diaphragm 101, the first electrode 102, the second diaphragm 103, and the second electrode 104 can be stacked and wound in sequence. After winding, the first diaphragm 101, the first electrode 102, the second diaphragm 103, and the second electrode 104 are cut to form a winding end. Then, a first adhesive layer 105 is formed between the outermost ring of the first electrode 102 and the first diaphragm 101 adjacent to the outermost ring of the first electrode 102, and a second adhesive layer 106 is formed between the outermost ring of the second electrode 104 and the second diaphragm 103 adjacent to the outermost ring of the second electrode 104.

[0083] In the above technical solution, the outermost ring of the first electrode 102 is connected to the first diaphragm 101 adjacent to the outermost ring of the first electrode 102 through the first adhesive layer 105, so that the position between the first electrode 102 and the first diaphragm 101 is relatively fixed. The outermost ring of the second electrode 104 is connected to the second diaphragm 103 adjacent to the outermost ring of the second electrode through the second adhesive layer 106, so that the position between the second electrode 104 and the second diaphragm 103 is relatively fixed. Since the winding ends of the first separator 101 and the second separator 103 are fixed to the outer surface of the electrode assembly, the positions of the first separator 101 adjacent to the outermost ring of the first electrode 102 and the second separator 103 adjacent to the outermost ring of the second electrode are fixed. This fixes the positions of the first electrode 102 fixed to the first separator 101 and the second electrode 104 fixed to the second separator 103, reducing the risk of relative sliding of the outermost rings of the first electrode 102 and the second electrode 104 during the charging and discharging process of the electrode assembly. It also keeps the gap between the first electrode 102 and the second electrode 104 small, resulting in a shorter lithium ion migration path between the first electrode 102 and the second electrode 104. This solves the problem of lithium ion deposition caused by a long lithium ion migration path between the first electrode 102 and the second electrode 104.

[0084] Continue to refer to Figure 4 as well as Figure 5 According to some embodiments of this application, the outermost ring of the first diaphragm 101 is located further away from the winding center of the electrode assembly than the outermost ring of the second diaphragm 103.

[0085] In other words, the first diaphragm 101 is located on the outermost side of the entire electrode assembly, the first adhesive layer 105 is located between the outermost ring of the first electrode 102 and the first diaphragm 101 located outside the outermost ring of the first electrode 102, and the second adhesive layer 106 is located between the outermost ring of the second electrode 104 and the second diaphragm 103 located outside the outermost ring of the second electrode 104. Thus, when the winding ends of the first electrode 102 and the second electrode 104 are aligned, only the second adhesive layer 106 is located between the first electrode 102 and the second electrode 104. When the winding end of the second electrode 104 extends beyond the winding end of the first electrode 102 along the winding direction of the electrode assembly, the second adhesive layer 106 can be located between the second electrode 104 and the second separator 103, which extend beyond the winding end of the first electrode 102. This ensures that the second adhesive layer 106 is not located between the first electrode 102 and the second electrode 104, and thus does not hinder the transport of lithium ions between the first electrode 102 and the second electrode 104.

[0086] In the above technical solution, the first separator 101 is located on the outermost side of the electrode assembly, and the first adhesive layer 105 is located on the side of the outermost first electrode 102 away from the outermost second electrode 104, rather than between the first electrode 102 and the second electrode 104. This avoids the problem of the first adhesive layer 105 being located between the first electrode 102 and the second electrode 104, which hinders the transport of lithium ions and helps maintain the normal charge and discharge performance of the electrode assembly.

[0087] refer to Figure 4 According to some embodiments of this application, the outermost ring of the second electrode 104 is divided into a first segment 1 and a second segment 2 adjacent to each other along the winding direction r of the electrode assembly. The winding end of the second electrode 104 is disposed in the second segment 2 along the winding direction r of the electrode assembly. The second segment 2 extends beyond the winding end of the first electrode 102. The second adhesive layer 106 connects the second segment 2 and the second diaphragm 103.

[0088] Figure 4 and Figure 5 The first and second segments are shown in a patterned fill, while the parts of the second electrode other than the first and second segments are shown in gray lines.

[0089] The winding direction r of the electrode assembly refers to the direction in which the assembly is wound around its winding center. The starting point of the winding direction r is the winding center, and the ending point is the winding end.

[0090] The end of the second segment 2 furthest from the first segment 1 is the winding end of the second electrode 104. The junction of the second segment 2 and the first segment 1 can be flush with the winding end of the first electrode 102. The outermost ring of the first electrode 102 is located outside the first segment 1, not outside the second segment 2. In other words, the second segment 2 can be the OH (Over-Hang) region of the second electrode 104. The OH region refers to the portion of the second electrode 104 that extends beyond the first electrode 102 in both length and width.

[0091] The second adhesive layer 106 is located between the second segment 2 and the second separator 103, such that the second adhesive layer 106 is offset from the outermost ring of the first electrode 102. That is, the second adhesive layer 106 is not located between the outermost ring of the first electrode 102 and the outermost ring of the second electrode 104, thus not hindering lithium-ion transport between the first electrode 102 and the second electrode 104. When the first separator 101 is located at the outermost edge of the entire electrode assembly, neither the first adhesive layer 105 nor the second adhesive layer 106 is located between the outermost ring of the first electrode 102 and the outermost ring of the second electrode 104.

[0092] In the above technical solution, the second adhesive layer 106 is located between the second segment 2 and the second separator 103, so that the second adhesive layer 106 is not located between the outermost ring of the first electrode 102 and the outermost ring of the second electrode 104, thus not hindering the lithium-ion transport between the first electrode 102 and the second electrode 104, which is beneficial to maintaining the normal charging and discharging performance of the electrode assembly.

[0093] Continue to refer to Figure 4 According to some embodiments of this application, the outermost ring of the first electrode 102 is divided into a third segment 3 and a fourth segment 4 adjacent to each other along the winding direction r of the electrode assembly. The third segment 3 is located on the side of the second segment 2 near the winding center of the electrode assembly and is directly opposite the second segment 2 through the first diaphragm 101. The fourth segment 4 is located on the side of the first segment 1 away from the winding center of the electrode assembly and is directly opposite the first segment 1 through the second diaphragm 103. The first adhesive layer 105 connects the fourth segment 4 and the first diaphragm 101.

[0094] Figure 4 and Figure 5 The third and fourth segments are shown in a patterned fill, while the parts of the first electrode other than the third and fourth segments are shown in black lines.

[0095] The end of the fourth segment 4 that is furthest from the third segment 3 is the winding end of the first electrode 102.

[0096] With the first diaphragm 101 located at the outermost edge of the entire electrode assembly, the outer edge of the first electrode 102 is the first diaphragm 101, and the outer edge of the second electrode 104 is the second diaphragm 103. The outermost ring of the first electrode 102 is located on the side of the outermost ring of the second electrode 104 furthest from the winding center. Since the second segment 2 extends beyond the winding end of the first electrode 102, the outermost rings of the first electrode 102 and the outermost rings of the second electrode 104 do not completely overlap along the winding direction r. Specifically, the second segment 2 is the portion of the second electrode 104 that extends beyond the winding end of the first electrode 102 along the winding direction r, and the third segment 3 is the portion of the first electrode 102 that extends beyond the starting position of the outermost ring of the second electrode 104 in the opposite direction of the winding direction r. Thus, the third segment 3 of the first electrode 102 is located inside the second segment 2 of the second electrode 104, and the fourth segment 4 of the first electrode 102 is located outside the first segment 1 of the second electrode 104. In other words, the outer side of the first diaphragm 101 located outside the fourth segment 4 does not have a second electrode 104, while the outer side of the first diaphragm 101 located outside the third segment 3 has a second electrode 104. In this embodiment, the first adhesive layer 105 is located between the fourth segment 4 and the first diaphragm 101 located outside the fourth segment 4. Compared to the first adhesive layer 105 being located between the third segment 3 and the first diaphragm 101, this arrangement ensures that the first adhesive layer 105 is not located between the outermost first electrode 102 and the outermost second electrode 104.

[0097] The first adhesive layer 105 may extend from the beginning position of the fourth segment 4 to the end position of the fourth segment 4; or, the first adhesive layer 105 may also be located at a portion of the fourth segment 4 and the first diaphragm 101 located outside the fourth segment 4. For example, the first adhesive layer 105 may also be located at a position near the winding end of the first electrode 102 between the fourth segment 4 and the first diaphragm 101 located outside the fourth segment 4.

[0098] In the above technical solution, when the second electrode 104 has a second segment 2, the first adhesive layer 105 is not located between the outermost first electrode 102 and the outermost second electrode 104, so as not to hinder the lithium-ion transport between the first electrode 102 and the second electrode 104, which is beneficial to maintaining the normal charging and discharging performance of the electrode assembly.

[0099] According to some embodiments of this application, when the first adhesive layer 105 connects the fourth segment 4 and the first diaphragm 101, the length of the first adhesive layer 105 connecting the fourth segment 4 and the first diaphragm 101 along the winding direction r of the electrode assembly is greater than or equal to 5 mm.

[0100] In other words, along the winding direction r of the electrode assembly, the length of the first adhesive layer 105 located between the fourth segment 4 and the first diaphragm 101 located outside the fourth segment 4 is greater than or equal to 5 mm and less than or equal to the length of the fourth segment 4. For example, the length of the first adhesive layer 105 located between the fourth segment 4 and the first diaphragm 101 located outside the fourth segment 4 can be 5 mm, 7 mm, 9 mm, 11 mm, 13 mm, or 15 mm, etc.

[0101] In the above technical solution, the length of the first adhesive layer 105 is sufficient to provide a good bonding effect on the first electrode 102 and the first diaphragm 101, thereby making the outermost ring of the first electrode 102 more firmly fixed on the first diaphragm 101.

[0102] refer to Figure 5 According to some embodiments of this application, the second adhesive layer 106 may further include a first extension 31, which extends out of the winding end of the second electrode 104 along the winding direction r of the electrode assembly. The first extension 31 is directly opposite to at least a portion of the fourth segment 4 of the first electrode 102 across the first diaphragm 101 and is bonded to the first diaphragm 101.

[0103] In other words, the first extension 31 is the portion of the second adhesive layer 106 that extends out of the winding end of the second electrode 104 along the winding direction r of the electrode assembly. The winding end of the second electrode 104 is located in the second segment 2. The second adhesive layer 106 is used to connect the second segment 2 of the second electrode 104 and the second diaphragm 103. With the first diaphragm 101 located on the outermost side of the entire electrode assembly, the second segment 2 is located outside the third segment 3, and the second segment 2 is directly opposite the third segment 3 across the first diaphragm 101. The third segment 3 is adjacent to the fourth segment 4. Therefore, the first extension 31 extends out of the winding end of the second electrode 104 and is located outside the fourth segment 4. Since the outer side of the first electrode 102 is the first diaphragm 101, the first extension 31 is directly opposite to at least part of the fourth segment 4 of the first electrode 102 across the first diaphragm 101. That is, the first extension 31 is located outside the fourth segment 4, and the first extension 31 and the fourth segment 4 are separated by the first diaphragm 101. The first extension 31 is also bonded to the adjacent first diaphragm 101.

[0104] The second adhesive layer 106 also includes a first body 32, which is the portion of the second adhesive layer 106 excluding the first extension 31. The first body 32 is located between the second segment 2 of the second electrode 104 and the second diaphragm 103. That is, a portion of the second adhesive layer 106 connects the second electrode 104 and the second diaphragm 103, and another portion of the second adhesive layer 106 connects the second electrode 104 and the first diaphragm 101.

[0105] Along the winding direction r of the electrode assembly, the extension length of the first extension 31 can be the same as the length of the first diaphragm 101 located outside the fourth segment 4, and the first extension 31 is fully bonded to the first diaphragm 101; or, the extension length of the first extension 31 can be less than the length of the first diaphragm 101 located outside the fourth segment 4.

[0106] In the above technical solution, the second electrode 104 is connected to the first separator 101 and the second separator 103 respectively through the second adhesive layer 106, which can enhance the stability of the second electrode 104 and further reduce the problem of the second electrode 104 moving under the expansion force of the electrode assembly, thereby further reducing the risk of relative sliding between the first electrode 102 and the second electrode 104. At the same time, the first extension 31 is bonded to the first separator 101 on the outer side of the fourth segment 4, and no second electrode 104 is provided on the outer side of the fourth segment 4. Therefore, the first extension 31 is not located between the first electrode 102 and the second electrode 104, and thus will not affect the lithium-ion transport between the first electrode 102 and the second electrode 104.

[0107] like Figure 4 as well as Figure 5 As shown, according to some embodiments of this application, the electrode assembly includes a straight portion and a bent portion, with the second adhesive layer 106 located in the bent portion.

[0108] The bent portions are located at opposite ends of the straight portions. The first electrode 102, the first diaphragm 101, the second electrode 104, and the second diaphragm 103 of the bent portions are bent relative to the first electrode 102, the first diaphragm 101, the second electrode 104, and the second diaphragm 103 of the straight portions. The bending shape may include, but is not limited to, an arc shape, a semi-circle shape, etc.

[0109] The third segment 3 of the first electrode 102 and the second segment 2 of the second electrode 104 can be located in one of the bends, and the fourth segment 4 of the first electrode 102 and the first segment 1 of the second electrode 104 can be located in the bend and the straight portion. For example, the two bends are referred to as the first bend and the second bend, and the third segment 3 of the first electrode 102 and the second segment 2 of the second electrode 104 can be located in the first bend. Along the winding direction r of the electrode assembly, the fourth segment 4 can be sequentially located in the first bend, the straight portion, the second bend, the straight portion, and the first bend. The first body 32 of the second adhesive layer 106 is located between the second segment 2 and the second diaphragm 103, and the first extension 31 of the second adhesive layer 106 faces the fourth segment 4 located in the first bend across the first diaphragm 101, thus placing the second adhesive layer 106 in the first bend, not in the straight portion.

[0110] It is understandable that a triangular space is formed between the extension line of the straight portion and the bend portion, and the second adhesive layer 106 is located in this space. In this way, compared to the second adhesive layer 106 being located in the straight portion, the overall thickness of the electrode assembly will not be increased in the direction perpendicular to the straight portion.

[0111] In the above technical solution, the second adhesive layer 106 is located at the bending part, which will not increase the overall thickness of the electrode assembly in the direction perpendicular to the straight part, thus maintaining the thinness of the electrode assembly and improving the energy density and space utilization of the battery cell.

[0112] According to some embodiments of this application, the length of the first extension 31 along the winding direction r of the electrode assembly is greater than or equal to 5 mm.

[0113] Along the winding direction r of the electrode assembly, the length of the first extension 31 is less than or equal to the length of the first diaphragm 101 located outside the fourth segment 4 and directly opposite the fourth segment 4. For example, along the winding direction r of the electrode assembly, the length of the first extension 31 can be 5mm, 7mm, 9mm, 11mm, 13mm, or 15mm, etc.

[0114] In the above technical solution, the length of the first extension 31 is sufficient to provide a good bonding effect on the second electrode 104 and the first diaphragm 101, so that the outermost ring of the second electrode 104 is fixedly and securely fixed on the first diaphragm 101 and is not prone to slippage under the expansion force of the electrode assembly.

[0115] refer to Figure 5 According to some embodiments of this application, along the winding direction r of the electrode assembly, the winding end of the second diaphragm 103 extends beyond the winding end of the first electrode 102. The first adhesive layer 105 may also include a second extension 41, which extends out of the winding end of the first electrode 102 along the winding direction r of the electrode assembly. The second extension 41 is bonded to the second diaphragm 103 that extends beyond the winding end of the first electrode 102.

[0116] In other words, the second extension 41 is the portion of the first adhesive layer 105 that extends beyond the winding end of the first electrode 102 along the winding direction r of the electrode assembly. When the first diaphragm 101 is located at the outermost edge of the entire electrode assembly, and the second segment 2 of the second electrode 104 extends beyond the winding end of the first electrode 102, the second diaphragm 103 extending beyond the winding end of the first electrode 102 is located at least outside the second segment 2, and the second diaphragm 103 extending beyond the winding end of the second electrode 104 becomes an unwound diaphragm. In some embodiments, along the winding direction r of the electrode assembly, the winding end of the first diaphragm 101 may also extend beyond the winding end of the first electrode 102, and the first diaphragm 101 extending beyond the winding end of the first electrode 102 also becomes an unwound diaphragm. In one example, the two opposing surfaces of the second extension 41 can be bonded with the second diaphragm 103 and the first diaphragm 101 forming the unwound diaphragm, respectively.

[0117] The winding end of the first electrode 102 is located at the fourth segment 4. The first adhesive layer 105 is used to connect the fourth segment 4 of the first electrode 102 and the first diaphragm 101. When the first diaphragm 101 is located at the outermost part of the entire electrode assembly, the fourth segment 4 is located outside the first segment 1, and the fourth segment 4 is directly opposite the first segment 1 through the second diaphragm 103. The second segment 2 is adjacent to the first segment 1. Therefore, the second extension 41 extends out of the winding end of the first electrode 102 and is located outside the second diaphragm 103, and is directly opposite the second segment 2 through the second diaphragm 103. The second extension 41 is also bonded to the second diaphragm 103. In other words, the second diaphragm 103, which is bonded to the second extension 41, is located at least outside the second segment 2. The second segment 2 is also bonded to the second diaphragm 103 located outside the second segment 2 through the second adhesive layer 106. This allows the fourth segment 4 of the first electrode 102 and the second segment 2 of the second electrode 104 to be connected to opposite surfaces of the same second diaphragm 103 through the first adhesive layer 105 and the second adhesive layer 106, respectively. Therefore, the first electrode 102 and the second electrode 104 are both fixed to the same second diaphragm 103, further reducing the risk of relative slippage between the first electrode 102 and the second electrode 104.

[0118] The first adhesive layer 105 also includes a second body 42, which is the portion of the first adhesive layer 105 excluding the second extension 41. The second body 42 is located between the fourth segment 4 of the first electrode 102 and the first diaphragm 101. That is, a portion of the first adhesive layer 105 connects the first electrode 102 and the first diaphragm 101, and another portion of the first adhesive layer 105 connects the first electrode 102 and the second diaphragm 103.

[0119] Along the winding direction r of the electrode assembly, the extension length of the second extension 41 can be less than or equal to the length of the second diaphragm 103 located outside the second segment 2, that is, the second extension 41 extends between the empty winding diaphragm corresponding to the first diaphragm 101 and the second diaphragm 103 located outside the second end; or, the extension length of the second extension 41 can also be greater than the length of the second diaphragm 103 located outside the second segment 2, that is, the second extension 41 extends between the empty winding diaphragm corresponding to the first diaphragm 101 and the empty winding diaphragm corresponding to the second diaphragm 103.

[0120] In some embodiments, where the electrode assembly includes a bent portion and a straight portion, the second extension 41 may be located at the bent portion of the electrode assembly.

[0121] In the above technical solution, by providing the second extension 41, the first electrode 102 and the second electrode 104 are respectively connected to the opposite two surfaces of the same second diaphragm 103. Therefore, the first electrode 102 and the second electrode 104 are both fixed to the same second diaphragm 103, further reducing the risk of relative slippage between the first electrode 102 and the second electrode 104.

[0122] It is worth noting that, Figure 5 As an example, a structure is shown where the first adhesive layer 105 includes a second extension 41 and the second adhesive layer 106 includes a first extension 31. In other embodiments, in the electrode assembly, the first adhesive layer may include a second extension, and the entire second adhesive layer may be located between the outermost ring of the second electrode 104 and the second diaphragm 103 adjacent to the outermost ring of the second electrode 104; or, in the electrode assembly, the second adhesive layer may include a first extension, and the entire first adhesive layer 105 may be located between the outermost ring of the first electrode 102 and the first diaphragm 101 adjacent to the outermost ring of the first electrode 102.

[0123] According to some embodiments of this application, the thickness of the first adhesive layer 105 is greater than or equal to 3 μm and less than or equal to 50 μm.

[0124] For example, the thickness of the first adhesive layer 105 can be 3μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm. The thickness of the first adhesive layer 105 referred to here is the thickness in the direction perpendicular to the surface of the first electrode 102.

[0125] By setting the first adhesive layer 105 within the aforementioned thickness range, the first adhesive layer 105 can achieve a good bonding effect while ensuring that the thickness of the first adhesive layer 105 is not too large. This can, to a certain extent, avoid the problem of local compression of the electrode assembly caused by the excessive thickness of the first adhesive layer 105, and maintain the structural integrity of the electrode assembly.

[0126] According to some embodiments of this application, the thickness of the second adhesive layer 106 is greater than or equal to 3 μm and less than or equal to 50 μm.

[0127] For example, the thickness of the second adhesive layer 106 can be 3μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, or 50μm. The thickness of the second adhesive layer 106 referred to here is the thickness in the direction perpendicular to the surface of the second electrode 104.

[0128] By setting the second adhesive layer 106 within the aforementioned thickness range, the second adhesive layer 106 can achieve a good bonding effect while ensuring that its thickness is not too large. This can, to a certain extent, avoid the problem of local compression of the electrode assembly caused by excessive thickness of the second adhesive layer 106, thus maintaining the structural integrity of the electrode assembly.

[0129] refer to Figure 6 According to some embodiments of this application, along the winding axis of the electrode assembly, the ratio of the width W1 of the first adhesive layer 105 to the width W2 of the first electrode 102 is greater than or equal to 0.5 and less than or equal to 1.

[0130] The axial direction of the electrode assembly refers to the direction of extension of the winding center axis of the electrode assembly. The first diaphragm 101, the first electrode 102, the second diaphragm 103, and the second electrode 104 are wound around the winding center axis to form the electrode assembly. In other words, in the flat state of the first diaphragm 101, the first electrode 102, the second diaphragm 103, and the second electrode 104, the width direction of the first electrode 102 is perpendicular to the length direction of the first electrode 102, and the first electrode 102 is wound along its length direction to form the electrode assembly. The winding axis of the electrode assembly is the same as the width direction of the first electrode 102 in the flat state.

[0131] For example, the ratio of the width W1 of the first adhesive layer 105 to the width W2 of the first electrode 102 can be 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1.

[0132] The ratio of the width of the first adhesive layer 105 to the width of the first electrode 102 is set within the above range, so that the bonding area of ​​the first adhesive layer 105 on the first electrode 102 is large, which can play a better role in fixing the first electrode 102 and effectively reduce the risk of relative slippage between the first electrode 102 and the second electrode 104.

[0133] refer to Figure 7 According to some embodiments of this application, along the winding axis of the electrode assembly, the ratio of the width W3 of the second adhesive layer 106 to the width W4 of the second electrode 104 is greater than 0.5 and less than or equal to 1.

[0134] The definition of the winding axis of the electrode assembly can be found in the relevant descriptions in the above embodiments, and will not be repeated here. The winding axis of the electrode assembly is the same as the width direction of the second electrode 104 in its flat state.

[0135] For example, the ratio of the width W3 of the second adhesive layer 106 to the width W4 of the second electrode 104 can be 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1.

[0136] The ratio of the width of the second adhesive layer 106 to the width of the second electrode 104 is set within the above range, so that the bonding area of ​​the second adhesive layer 106 on the second electrode 104 is large, which can play a better role in fixing the second electrode 104 and effectively reduce the risk of relative slippage between the first electrode 102 and the second electrode 104.

[0137] This application provides a battery device, which includes the battery cell described in the above embodiments.

[0138] The battery device can be referred to the relevant description in the above embodiments, and will not be repeated here.

[0139] The battery device has the beneficial effects of the battery cell provided in the embodiments of this application. For details, please refer to the specific description of the battery cell in the above embodiments, which will not be repeated here.

[0140] This application provides an electrical device that includes the battery device described in the above embodiments, the battery device being used to provide electrical energy.

[0141] The electrical device has the beneficial effects of the battery device provided in the embodiments of this application. For details, please refer to the specific descriptions of the battery device in the above embodiments, which will not be repeated here.

[0142] This application provides an energy storage device, which includes the battery device described in the above embodiments, and the battery device is used to store electrical energy.

[0143] The energy storage device has the beneficial effects of the battery device provided in the embodiments of this application. For details, please refer to the specific descriptions of the battery device in the above embodiments, which will not be repeated here.

[0144] This application provides a single battery cell, as referenced in the embodiments. Figure 4 as well as Figure 5The battery cell includes: a first separator 101, a first electrode 102, a second separator 103, and a second electrode 104. The first separator 101, the first electrode 102, the second separator 103, and the second electrode 104 are sequentially stacked and wound to form an electrode assembly. The battery cell also includes: a first adhesive layer 105, at least partially located between the outermost ring of the first electrode 102 and the first separator 101 adjacent to the outermost ring of the first electrode 102 to connect the first separator 101 and the first electrode 102; and a second adhesive layer 106, at least partially located between the outermost ring of the second electrode 104 and the second separator 103 adjacent to the outermost ring of the second electrode 104 to connect the second separator 103 and the second electrode 104. The winding ends of the first separator 101 and the second separator 103 are also fixed to the outer surface of the electrode assembly. The outermost ring of the first separator 101 is located further away from the winding center of the electrode assembly than the outermost ring of the second separator 103.

[0145] like Figure 4 As shown, exemplarily, the outermost ring of the second electrode 104 is divided into a first segment 1 and a second segment 2 adjacent to each other along the winding direction r of the electrode assembly. The winding end of the second electrode 104 is disposed in the second segment 2. Along the winding direction r of the electrode assembly, the second segment 2 extends beyond the winding end of the first electrode 102. The second adhesive layer 106 connects the second segment 2 and the second diaphragm 103. The outermost ring of the first electrode 102 is divided into a third segment 3 and a fourth segment 4 adjacent to each other along the winding direction r of the electrode assembly. The third segment 3 is located on the side of the second segment 2 near the winding center of the electrode assembly and is directly opposite the second segment 2 across the first diaphragm 101. The fourth segment 4 is located on the side of the first segment 1 away from the winding center of the electrode assembly and is directly opposite the first segment 1 across the second diaphragm 103. The first adhesive layer 105 connects the fourth segment 4 and the first diaphragm 101.

[0146] Along the winding direction r of the electrode assembly, the length of the first adhesive layer 105 connecting the fourth segment 4 and the first diaphragm 101 is greater than or equal to 5 mm.

[0147] For example, such as Figure 5 As shown, the second adhesive layer 106 may also include a first extension 31, which extends out of the winding end of the second electrode 104 along the winding direction r of the electrode assembly. The first extension 31 is directly opposite to at least a portion of the fourth segment 4 of the first electrode 102 across the first diaphragm 101 and is bonded to the first diaphragm 101.

[0148] The electrode assembly includes a straight portion and a bent portion, with the second adhesive layer 106 located in the bent portion. Along the winding direction r of the electrode assembly, the length of the first extension 31 is greater than or equal to 5 mm.

[0149] For example, such as Figure 5As shown, along the winding direction r of the electrode assembly, the winding end of the second diaphragm 103 extends beyond the winding end of the first electrode 102. The first adhesive layer 105 may also include a second extension 41, which extends out of the winding end of the first electrode 102 along the winding direction r of the electrode assembly. The second extension 41 is bonded to the second diaphragm 103 that extends beyond the winding end of the first electrode 102.

[0150] The thickness of the first adhesive layer 105 is greater than or equal to 3 μm and less than or equal to 50 μm. The thickness of the second adhesive layer 106 is greater than or equal to 3 μm and less than or equal to 50 μm. Along the winding axis of the electrode assembly, the ratio of the width of the first adhesive layer 105 to the width of the first electrode 102 is greater than or equal to 0.5 and less than or equal to 1, and the ratio of the width of the second adhesive layer 106 to the width of the second electrode 104 is greater than 0.5 and less than or equal to 1.

[0151] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: A first diaphragm, a first electrode, a second diaphragm, and a second electrode are sequentially stacked and wound to form an electrode assembly. The battery cell also includes: A first adhesive layer, at least partially located between the outermost ring of the first electrode and the first diaphragm adjacent to the outermost ring of the first electrode, connects the first diaphragm and the first electrode. The second adhesive layer is at least partially located between the outermost ring of the second electrode and the second diaphragm adjacent to the outermost ring of the second electrode to connect the second diaphragm and the second electrode, wherein the winding ends of the first diaphragm and the second diaphragm are also fixed to the outer surface of the electrode assembly.

2. The battery cell according to claim 1, characterized in that, The outermost ring of the first diaphragm is located further away from the winding center of the electrode assembly than the outermost ring of the second diaphragm.

3. The battery cell according to claim 1 or 2, characterized in that, The outermost ring of the second electrode is divided into a first segment and a second segment adjacent to each other along the winding direction of the electrode assembly. The winding end of the second electrode is located in the second segment. Along the winding direction of the electrode assembly, the second segment extends beyond the winding end of the first electrode. The second adhesive layer connects the second segment and the second diaphragm.

4. The battery cell according to claim 3, characterized in that, The outermost ring of the first electrode is divided into a third segment and a fourth segment adjacent to each other along the winding direction of the electrode assembly, wherein, The third segment is located on the side of the second segment near the winding center of the electrode assembly, and is directly opposite the second segment through the first diaphragm; The fourth segment is located on the side of the first segment away from the winding center of the electrode assembly, and is directly opposite the first segment through the second diaphragm. The first adhesive layer connects the fourth segment and the first diaphragm.

5. The battery cell according to claim 4, characterized in that, Along the winding direction of the electrode assembly, the length of the first adhesive layer connecting the fourth segment and the first diaphragm is greater than or equal to 5 mm.

6. The battery cell according to claim 4 or 5, characterized in that, The second adhesive layer includes a first extension that extends out of the winding end of the second electrode along the winding direction of the electrode assembly. The first extension is directly opposite to at least a portion of the fourth segment of the first electrode across the first diaphragm and is bonded to the first diaphragm.

7. The battery cell according to claim 6, characterized in that, The electrode assembly includes a straight portion and a bent portion, with the second adhesive layer located in the bent portion.

8. The battery cell according to claim 6 or 7, characterized in that, Along the winding direction of the electrode assembly, the length of the first extension is greater than or equal to 5 mm.

9. The battery cell according to any one of claims 2-8, characterized in that, Along the winding direction of the electrode assembly, the winding end of the second diaphragm extends beyond the winding end of the first electrode sheet. The first adhesive layer includes a second extension, which extends beyond the winding end of the first electrode sheet along the winding direction of the electrode assembly. The second extension is bonded to the second diaphragm that extends beyond the winding end of the first electrode sheet.

10. The battery cell according to any one of claims 1-9, characterized in that, The thickness of the first adhesive layer is greater than or equal to 3 μm and less than or equal to 50 μm.

11. The battery cell according to any one of claims 1-10, characterized in that, The thickness of the second adhesive layer is greater than or equal to 3 μm and less than or equal to 50 μm.

12. The battery cell according to any one of claims 1-11, characterized in that, Along the winding axis of the electrode assembly, the ratio of the width of the first adhesive layer to the width of the first electrode sheet is greater than or equal to 0.5 and less than or equal to 1.

13. The battery cell according to any one of claims 1-12, characterized in that, Along the winding axis of the electrode assembly, the ratio of the width of the second adhesive layer to the width of the second electrode sheet is greater than 0.5 and less than or equal to 1.

14. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-13.

15. An electrical appliance, characterized in that, Includes the battery device as described in claim 14.

16. An energy storage device, characterized in that, The energy storage device includes the battery device as described in claim 14, the battery device being used to store electrical energy.

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