Electrode assembly, battery cell, battery and electrical device

Abstract

An electrode assembly (20), a battery cell (100), a battery (200), and an electrical device (1000). The electrode assembly (20) comprises a first electrode sheet (21), a second electrode sheet (22) and a separator (23). The second electrode sheet (22) is stacked with the first electrode sheet (21) in the thickness direction of the first electrode sheet (21). The polarities of the second electrode sheet (22) and the first electrode sheet (21) are opposite. The separator (23) isolates the first electrode sheet (21) from the second electrode sheet (22), and is stacked with the first electrode sheet (21) in the thickness direction of the first electrode sheet (21). The separator (23), the first electrode sheet (21) and the second electrode sheet (22) are wound to form a whole. At a starting end (201) and / or an ending end (202) of the winding of the electrode assembly (20), at least one of the first electrode sheet (21) and the second electrode sheet (22) is fixed to the separator (23) by means of a connector (24).

Description

Electrode assemblies, battery cells, batteries and electrical equipment

[0001] Priority information

[0002] This application claims priority and benefits of patent application No. 202322662392.5 filed with the State Intellectual Property Office of China on September 28, 2023, and the entire text of which is incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to an electrode assembly, a battery cell, a battery, and an electrical device. Background Art

[0004] With the development of the battery industry, batteries are increasingly used in a wide range of applications, and battery safety issues are attracting attention. In related technologies, a battery cell comprises an electrode assembly, which includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator separates the positive and negative electrode sheets. To reduce the probability of the positive and negative electrode sheets slipping relative to the separator and short-circuiting, the separator is generally longer to cover the positive and negative electrode sheets. However, longer separators result in material waste.

[0005] Summary of the Invention

[0006] The present application provides an electrode assembly, a battery cell, a battery and an electrical device, which can solve the problem of material waste caused by a long diaphragm of the electrode assembly.

[0007] The electrode assembly of the embodiment of the present application includes a first electrode sheet, a second electrode sheet, and a diaphragm. The second electrode sheet is stacked with the first electrode sheet along the thickness direction of the first electrode sheet, and the polarity of the second electrode sheet is opposite to that of the first electrode sheet. The diaphragm separates the first electrode sheet from the second electrode sheet and is stacked with the first electrode sheet along the thickness direction of the first electrode sheet.

[0008] The diaphragm, the first pole piece and the second pole piece are wound into one body, and at the starting end and / or the ending end of the winding of the electrode assembly, at least one of the first pole piece and the second pole piece is fixed to the diaphragm through a connector.

[0009] In the electrode assembly of the embodiment of the present application, at the starting end and / or the ending end of the winding of the electrode assembly, at least one of the first pole piece and the second pole piece is fixed to the diaphragm through a connector, so that at least one of the first pole piece and the second pole piece will not slip relative to the diaphragm, and it is difficult for the first pole piece and the second pole piece to short-circuit. Therefore, there is no need to set a longer diaphragm at the starting end and / or the ending end of the electrode assembly, thereby improving the utilization rate of the diaphragm material and reducing the waste of diaphragm material.

[0010] In certain embodiments, the connector includes a colloid, and at least one of the first electrode piece and the second electrode piece is fixed to the separator via the colloid. This makes the colloid readily available, reducing the cost of the electrode assembly. Furthermore, the colloid's adhesive properties provide a more stable connection between the electrode piece and the separator.

[0011] In certain embodiments, the colloid bonds the first electrode piece and the diaphragm along the thickness direction of the diaphragm, and / or the colloid bonds the second electrode piece and the diaphragm along the thickness direction of the diaphragm. This increases the bonding area of ​​the colloid, facilitating more stable bonding between the electrode piece and the diaphragm.

[0012] In some embodiments, the colloid is symmetrically arranged about the center of the width of the electrode to which the diaphragm is bonded. Thus, the colloid extends from the center of the width of the electrode to both edges, making the bonding force between the diaphragm and the electrode more uniform and facilitating a more stable bonding between the electrode and the diaphragm.

[0013] In some embodiments, the width of the colloid is a first width, the width of the electrode bonded to the diaphragm is a second width, and the ratio of the first width to the second width is in the range of 0.5-1. In this way, the width of the colloid bonding the diaphragm and the electrode is larger, which is conducive to stable bonding of the colloid to the electrode and the diaphragm.

[0014] In certain embodiments, the length of the colloid along the length of the electrode bonded to the diaphragm ranges from 2 mm to 100 mm. Within this range, the adhesive force formed by the colloid can stably bond the electrode and diaphragm, while obstructing a small area of ​​the diaphragm, thereby minimizing the impact on the chemical reaction between the first and second electrode pieces.

[0015] In some embodiments, the thickness of the colloid is less than 20 μm. In this way, if the adhesive force of the colloid is sufficient, the smaller the thickness of the colloid, the less impact on the air permeability of the diaphragm, and thus the less impact on the chemical reaction between the first electrode and the second electrode.

[0016] In certain embodiments, the electrode sheet bonded to the separator includes a current collector and a coating layer, the coating layer being laminated on the current collector. The starting and / or ending ends of the coating layer winding form grooves facing away from the current collector, with the colloid at least partially contained within the grooves. This ensures that the colloid is at least partially contained within the grooves, resulting in a smoother surface at the starting and ending ends of the electrode assembly winding, reducing the likelihood of interference with other components.

[0017] In certain embodiments, there are two separators, and one of the first and second electrode sheets is sandwiched between the two separators. At the starting and / or ending ends of the winding of the electrode assembly, both separators are secured to the sandwiched electrode sheet via the connector. Thus, both separators are secured to the sandwiched electrode sheet via the connector, further stabilizing the relative position of the sandwiched electrode sheet and the separator, thereby reducing the risk of shorting between the first and second electrode sheets.

[0018] In certain embodiments, the electrode assembly includes adhesive tape, and at the starting and / or ending ends of the winding of the electrode assembly, another electrode piece other than the clamped electrode piece is connected to the adjacent separator via the adhesive tape. This allows the position of the other electrode piece other than the clamped electrode piece to be fixed, ensuring accurate positioning of the two electrode pieces, reducing lithium deposition in the electrode assembly, and thereby improving the safety of the electrode assembly.

[0019] The battery cell according to the embodiment of the present application includes the electrode assembly according to any one of the above embodiments.

[0020] The battery according to the embodiment of the present application includes the battery cell described in any of the above embodiments.

[0021] The electrical equipment of the embodiment of the present application includes the battery cell described in any of the above embodiments or the battery described in the above embodiments.

[0022] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] FIG1 is a schematic diagram of the structure of an electrical device provided in some embodiments of the present application;

[0025] FIG2 is a schematic structural diagram of a battery provided in some embodiments of the present application;

[0026] FIG3 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0027] FIG4 is a schematic structural diagram of an electrode assembly provided in some embodiments of the present application;

[0028] FIG5 is an enlarged schematic diagram of portion A of the electrode assembly of FIG4 ;

[0029] FIG6 is a schematic diagram of the coordination between the electrode and the colloid provided in some embodiments of the present application;

[0030] FIG7 is a structural perspective view of an electrode assembly provided in some embodiments of the present application;

[0031] FIG8 is an enlarged schematic diagram of portion B of the electrode assembly of FIG7 ;

[0032] FIG9 is a structural perspective view of an electrode assembly provided in some embodiments of the present application;

[0033] FIG10 is an enlarged schematic diagram of portion C of the electrode assembly of FIG9 .

[0034] Explanation of the accompanying numbers: 1000-electrical equipment, 200-battery, 300-controller, 400-motor, 100-battery cell, 10-shell, 20-electrode assembly, 21-first pole piece, 211-current collector, 212-coating layer, 213-groove, 22-second pole piece, 23-diaphragm, 201-starting end, 202-ending end, 24-connector, 241-colloid, tape 25. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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).

[0041] 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.

[0042] 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.

[0043] Currently, market developments indicate that batteries are increasingly being 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 cars, as well as in aerospace and other fields. As battery applications continue to expand, market demand is also growing.

[0044] A battery cell includes an electrode assembly, which includes a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly can be wound into an integral body. During the winding process of the electrode assembly, at the starting end and the first and last ends of the winding of the electrode assembly, at least one of the positive electrode sheet and the negative electrode sheet is likely to slip relative to the separator, causing the positive electrode sheet and the negative electrode sheet to extend beyond the edge of the separator and short-circuit. In order to reduce the probability of the positive electrode sheet and the negative electrode sheet slipping relative to the separator and short-circuiting, the separator is generally provided with a longer length that exceeds the edge of the sheet at the starting end and the first and last ends of the winding. This ensures that even if at least one of the positive electrode sheet and the negative electrode sheet is likely to slip relative to the separator, the positive electrode sheet and the negative electrode sheet will not extend beyond the edge of the separator. However, a longer separator length is likely to result in material waste.

[0045] In order to solve the problem that the diaphragm is long and easily causes material waste, at the starting end and / or the ending end of the winding of the electrode assembly, at least one of the first pole piece and the second pole piece is fixed to the diaphragm through a connector, so that at least one of the first pole piece and the second pole piece will not slip relative to the diaphragm, and the first pole piece and the second pole piece are unlikely to short-circuit, thereby eliminating the need to set a longer diaphragm at the starting end and / or the ending end of the electrode assembly, thereby improving the utilization rate of the diaphragm material and reducing the material waste of the diaphragm.

[0046] It should be noted that, in this application, "electrode piece" may refer to the first electrode piece or the second electrode piece. One of the first electrode piece and the second electrode piece is a positive electrode piece, and the other is a negative electrode piece.

[0047] The electrical devices of the embodiments of the present application include battery cells or batteries in any of the following embodiments. Specifically, the electrical devices may use batteries or battery cells as a power source, and the electrical devices may include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, 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 spacecraft may include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0048] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electric device 1000 according to an embodiment of the present application.

[0049] Please refer to Figure 1, which is a schematic diagram of the structure of an electric device 1000 provided in some embodiments of the present application. A battery 200 is installed inside the vehicle. Battery 200 can be located at the bottom, front, or rear of the vehicle. Battery 200 can be used to power the vehicle, for example, as the vehicle's operating power source.

[0050] The vehicle may further include a controller 300 and a motor 400 . The controller 300 is used to control the battery 200 to supply power to the motor 400 , for example, to meet the vehicle's power requirements for starting, navigating, and driving.

[0051] In the embodiment of the present application, the battery 200 can not only serve as the operating power source of the vehicle, but also serve as the driving power source of the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0052] Please refer to Figure 2, which is a schematic diagram of the structure of a battery 200 provided in some embodiments of the present application. The battery 200 according to an embodiment of the present application includes a battery cell 100 according to any of the following embodiments. As such, since the electrode assembly in the battery cell can be effectively wetted and the function of the insulating film is not significantly affected, the battery according to the embodiment of the present application has good performance and can operate continuously and stably in a safe environment.

[0053] In the embodiments of the present application, the battery cell 100 may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., and the embodiments of the present application are not limited to this. The battery cell 100 may be cylindrical, flat, rectangular, or other shapes, and the embodiments of the present application are not limited to this. The battery cell 100 is generally divided into three types according to the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of the present application are not limited to this.

[0054] The battery 200 generally includes a battery case 210 for encapsulating one or more battery cells 100. Multiple batteries can be housed in the battery case 210, which can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells 100. As the carrier of the battery module, the battery case 210 plays a key role in the safe operation and protection of the battery module. The battery case 210 must meet the strength and stiffness requirements and the protection level requirements of the electrical equipment casing, while providing collision protection. The shape of the battery case 210 can be a rectangular parallelepiped, a cube, etc. The battery case 210 can be cast with materials such as steel plates and aluminum alloys; new lightweight materials can also be used, such as glass fiber reinforced composite materials, carbon fiber reinforced composite materials, etc.

[0055] Please refer to FIG3 , which is a disassembled view of a battery cell 100 provided in some embodiments of the present application. In certain embodiments, the battery cell 100 includes a housing 10 and an electrode assembly 20 , wherein the electrode assembly 20 is disposed in the housing 10 .

[0056] The electrode assembly 20 is a component where electrochemical reactions occur in the battery cell 100. One or more electrode assemblies 20 may be contained within the housing 10 of the battery cell 100.

[0057] Please refer to Figures 4 and 5. Figure 4 is a schematic diagram of the structure of the electrode assembly 20 provided in some embodiments of the present application. Figure 5 is an enlarged schematic diagram of part A of the electrode assembly of Figure 4. The electrode assembly 20 of the embodiment of the present application includes a first electrode piece 21, a second electrode piece 22 and a diaphragm 23. The second electrode piece 22 is stacked with the first electrode piece 21 along the thickness direction of the first electrode piece 21, and the polarity of the second electrode piece 22 is opposite to that of the first electrode piece 21; the diaphragm 23 isolates the first electrode piece 21 from the second electrode piece 22, and is stacked with the first electrode piece 21 along the thickness direction of the first electrode piece 21;

[0058] The diaphragm 23 , the first electrode piece 21 and the second electrode piece 22 are wound into one body. At the starting end 201 and / or the ending end 202 of the electrode assembly 20 , at least one of the first electrode piece 21 and the second electrode piece 22 is fixed to the diaphragm 23 via a connector 24 .

[0059] Specifically, the first electrode 21 and the second electrode 22 are two electrode sheets with opposite polarities. During the charge and discharge process of the battery cell 100, the positive electrode active material and the negative electrode active material may react with the electrolyte.

[0060] The diaphragm 23 isolates the first electrode piece 21 and the second electrode piece 22. That is, a diaphragm 23 is provided between the first electrode piece 21 and the second electrode piece 22. The first electrode piece 21 and the second electrode piece 22 are spaced apart from each other and do not contact each other, thereby reducing the risk of short circuit between the first electrode piece 21 and the second electrode piece 22.

[0061] The first pole piece 21, the second pole piece 22 and the diaphragm 23 are stacked on each other in their respective thickness directions. The diaphragm 23, the first pole piece 21 and the second pole piece 22 are wound into a cylindrical shape or a substantially square shape.

[0062] In one example, at the starting end 201 of the winding of the electrode assembly 20 , at least one of the first electrode sheet 21 and the second electrode sheet 22 is fixed to the diaphragm 23 via a connector 24 .

[0063] In another example, at the winding end 202 of the electrode assembly 20 , at least one of the first electrode sheet 21 and the second electrode sheet 22 is fixed to the diaphragm 23 via a connector 24 .

[0064] In another example, at least one of the first electrode sheet 21 and the second electrode sheet 22 at the starting end 201 and the ending end 202 of the electrode assembly 20 is fixed to the separator 23 via a connector 24 .

[0065] In this way, at the starting end 201 and / or the ending end 202 of the electrode assembly 20, at least one of the first electrode piece 21 and the second electrode piece 22 is fixed to the diaphragm 23 through the connector 24, so that at least one of the first electrode piece 21 and the second electrode piece 22 will not slip relative to the diaphragm 23, and it is difficult for the first electrode piece 21 and the second electrode piece 22 to short-circuit. There is no need to set a longer diaphragm 23 at the starting end 201 and / or the ending end 202 of the electrode assembly 20, which improves the utilization rate of the diaphragm 23 material and reduces the material waste of the diaphragm 23.

[0066] In some embodiments, the connector 24 includes a colloid 241 , and at least one of the first pole piece 21 and the second pole piece 22 is fixed to the diaphragm 23 via the colloid 241 .

[0067] Specifically, the colloid 241 may be, for example, double-sided tape or a liquid adhesive formed after solidification. The colloid 241 may be made of materials such as epoxy resin, phenolic resin, urea-formaldehyde resin, and polyurethane. It should be noted that the colloid 241 may have a certain degree of elasticity so that it does not damage the electrode and diaphragm 23.

[0068] In one example, the colloid 241 bonds the first pole piece 21 to the diaphragm 23 . In another example, the colloid 241 bonds the second pole piece 22 to the diaphragm 23 . In yet another example, both the first pole piece 21 and the second pole piece 22 are bonded and fixed to the diaphragm 23 by the colloid 241 .

[0069] Thus, the colloid 241 is easily available, which reduces the manufacturing cost of the electrode assembly 20. In addition, the colloid 241 is viscous, which can make the connection between the electrode and the separator 23 more stable.

[0070] In other embodiments, the connector 24 may include components such as pins, which may pass through the pole piece and the diaphragm 23 to fix the pole piece and the diaphragm 23 together.

[0071] In some embodiments, the colloid 241 bonds the first electrode piece 21 and the diaphragm 23 along the thickness direction of the diaphragm 23 , and / or the colloid 241 bonds the second electrode piece 22 and the diaphragm 23 along the thickness direction of the diaphragm 23 .

[0072] It can be understood that the diaphragm 23 has a larger surface area in the thickness direction of the diaphragm 23 , and therefore the bonding area of ​​the colloid 241 is larger, which is conducive to more stable bonding of the colloid 241 to the electrode and the diaphragm 23 .

[0073] In one example, when the diaphragm 23 and the first pole piece 21 are bonded together by the colloid 241, the colloid 241 bonds the first pole piece 21 and the diaphragm 23 along the thickness direction of the diaphragm 23. In another example, when the diaphragm 23 and the second pole piece 22 are bonded together by the colloid 241, the colloid 241 bonds the second pole piece 22 and the diaphragm 23 along the thickness direction of the diaphragm 23.

[0074] Referring to FIG. 6 , in certain embodiments, the colloid 241 is symmetrically arranged about the center of the width direction of the electrode sheet bonded to the diaphragm 23. In one example, when the diaphragm 23 and the first electrode sheet 21 are bonded via the colloid 241, the colloid 241 is symmetrically arranged about the center of the width direction of the first electrode sheet 21. In another example, when the diaphragm 23 and the second electrode sheet 22 are bonded via the colloid 241, the colloid 241 is symmetrically arranged about the center of the width direction of the second electrode sheet 22.

[0075] The width of the electrode sheet is perpendicular to its thickness, and the length of the electrode sheet is perpendicular to its width. Generally, the electrode assembly 20 is wound along its length. Therefore, at the starting end 201 or the first and last ends of the winding of the electrode assembly 20, the width of the electrode sheet is in an expanded state.

[0076] In this way, the colloid 241 extends from the center of the electrode in the width direction to the two edges, so that the bonding force between the diaphragm 23 and the electrode is more uniform, which is conducive to more stable bonding of the electrode and the diaphragm 23.

[0077] It should be noted that, on the same surface of the diaphragm 23 , the colloid 241 may extend continuously along the width direction of the diaphragm 23 , or may be distributed discontinuously along the width direction of the diaphragm 23 .

[0078] Of course, in other embodiments, the colloid 241 may be glued to the long edge of the electrode and the diaphragm 23 .

[0079] In certain embodiments, the width of the colloid 241 is a first width W1, and the width of the electrode bonded to the diaphragm 23 is a second width W2. The ratio of the first width W1 to the second width W2 is in the range of 0.5-1 (0.5≤W1 / W2≤1). For example, the ratio W1 / W2 of the first width W1 to the second width W2 can be 0.5, 0.6, 0.7, 0.8, 0.9, or 1. In this way, the colloid 241 occupies a larger portion of the width of the electrode, and the width of the colloid 241 bonding the diaphragm 23 and the electrode is larger, which facilitates stable bonding of the colloid 241 to the electrode and the diaphragm 23.

[0080] In one example, the ratio of the width of the colloid 241 to the width of the first electrode 21 is in the range of 0.5-1. In another example, the ratio of the width of the colloid 241 to the width of the second electrode 22 is in the range of 0.5-1.

[0081] It should be noted that, when there are multiple colloids 241 , the ratios of the widths of different colloids 241 to the width of the electrode may be the same or different.

[0082] Referring to Figure 5 , in certain embodiments, the length of the colloid 241 along the length of the electrode bonded to the diaphragm 23 ranges from 2 mm to 100 mm (0.5 ≤ L ≤ 1). For example, the length L of the colloid 241 can be 2 mm, 10 mm, 20 mm, 50 mm, 80 mm, 100 mm, etc. As discussed above, the electrode is wound along its length. Therefore, if the colloid 241 is rolled into a curved state, the length of the colloid 241 is the length of the colloid 241 in the flattened state.

[0083] Thus, when the length L of the colloid 241 is within the above range, the adhesive force formed by the colloid 241 can stably bond the electrode and the diaphragm 23 , and the area of ​​the diaphragm 23 blocked is small, which has little effect on the chemical reaction between the first electrode 21 and the second electrode 22 .

[0084] It should be noted that, when there are multiple colloids 241 , the lengths of different colloids 241 may be the same or different.

[0085] Referring to FIG. 5 , in some embodiments, the thickness H of the colloid 241 is less than 20 μm. For example, the thickness H of the colloid 241 can be 19 μm, 15 μm, 10 μm, 8 μm, 5 μm, or the like. Thus, if the adhesive force of the colloid 241 is sufficient, the thickness of the colloid 241 is relatively small, which has a relatively small impact on the air permeability of the diaphragm 23 and, consequently, on the chemical reaction between the first electrode 21 and the second electrode 22. Furthermore, the thickness of the colloid 241 also has a relatively small impact on the degree of deformation of the electrode or diaphragm 23, allowing the electrode assembly 20 to function normally.

[0086] In some embodiments, the electrode bonded to the diaphragm 23 includes a current collector 211 and a coating layer 212, the coating layer 212 is stacked on the current collector 211, and the starting end and / or the ending end of the coating layer 212 are wound to form a groove 213 away from the current collector 211, and the colloid 241 is at least partially accommodated in the groove 213.

[0087] Specifically, the groove 213 may be a rectangular groove 213, an arc-shaped groove 213, or the like. The groove 213 may connect the longitudinal edge and the width edge of the coating layer 212. The depth of the groove 213 may be 0.3-0.8 times the thickness of the coating layer 212. When the groove 213 is deep enough, the colloid 241 can be completely accommodated in the groove 213.

[0088] In summary, the colloid 241 is at least partially accommodated in the groove 213 , so that the surfaces of the starting end 201 and the ending end 202 of the electrode assembly 20 are relatively smooth, thereby reducing the probability of interference between the electrode assembly 20 and other components.

[0089] Referring to FIG. 7 and FIG. 8 , in some embodiments, the groove may be omitted. In this case, the colloid 241 may cause the diaphragm 23 to bulge slightly, but such bulge will not affect the normal use of the electrode assembly 20 .

[0090] In some embodiments, there are two diaphragms 23, and one of the first electrode piece 21 and the second electrode piece 22 is clamped between the two diaphragms 23. At the starting end 201 and / or the ending end 202 of the electrode assembly 20, the two diaphragms 23 are fixed to the clamped electrode piece through a connector 24.

[0091] In one example, the first electrode sheet 21 is sandwiched between two separators 23. At the starting end 201 and the ending end 202 of the electrode assembly 20, the two separators 23 are fixed to the first electrode sheet 21 by a colloid 241. In another example, the second electrode sheet 22 is sandwiched between the two separators 23. At the starting end 201 and the ending end 202 of the electrode assembly 20, the two separators 23 are fixed to the second electrode sheet 22 by a colloid 241.

[0092] In this way, both diaphragms 23 are fixed to the clamped pole piece through the connector 24 , which can further stabilize the relative position of the clamped pole piece and the diaphragm 23 and reduce the risk of short circuit between the first pole piece 21 and the second pole piece 22 .

[0093] Please refer to Figures 9 and 10. In some embodiments, the electrode assembly 20 includes a tape 25. At the starting end 201 and / or the ending end 202 of the electrode assembly 20, another electrode piece other than the clamped electrode piece is connected to the adjacent diaphragm through the tape 25.

[0094] In one example, the first electrode piece 21 is sandwiched between two diaphragms 23. At the starting end 201 and the ending end 202 of the electrode assembly 20, the two diaphragms 23 are fixed to the first electrode piece 21 by the colloid 241. One end of the tape 25 is bonded to the end of the second electrode piece 22, and the other end is connected to the end of the adjacent diaphragm 23.

[0095] It can be understood that in the first electrode 21 and the second electrode 22, the orthographic projection of one electrode on the other electrode is completely within the outline of the other electrode, so that lithium ions can completely adhere to the other electrode during flow. Therefore, the relative position of the two electrode plates is extremely important.

[0096] For example, during the manufacturing process of the electrode assembly 200, the first electrode sheet 21, the second electrode sheet 22 and the two diaphragms 23 can be flattened first, and the corresponding winding ends and tail ends can be fixed first, and then wound, so that the first electrode sheet 21, the second electrode sheet 22 and the two diaphragms 23 will not be positionally shifted during the winding process, thereby improving the pass rate of the electrode assembly 20.

[0097] In this way, the position of the other electrode piece except the clamped electrode piece can be fixed, so that the positions of the two electrode pieces are accurate, the phenomenon of lithium deposition in the electrode assembly 20 is reduced, and the safety of the electrode assembly 20 is improved.

[0098] Referring to Figure 10 , in certain embodiments, the connection length between the tape 25 and the electrode sheet along the winding path of the electrode assembly 20 ranges from 3 mm to 20 mm. For example, the connection length C1 between the tape 25 and the electrode sheet can be 3 mm, 5 mm, 12 mm, 16 mm, 20 mm, etc. This provides a relatively stable connection between the tape 25 and the electrode sheet.

[0099] Referring to FIG. 10 , in certain embodiments, the connection length between the tape 25 and the separator 23 along the winding path of the electrode assembly 20 ranges from 3 mm to 40 mm. For example, the connection length C2 between the tape 25 and the electrode sheet ranges from 3 mm to 15 mm, 20 mm, 30 mm, or 40 mm. This provides a relatively stable connection between the tape 25 and the separator 23.

[0100] In some embodiments, the tape 25 is embedded in a depression formed on the surface of the diaphragm 23, so that the structure of the tape 25 and the diaphragm 23 is more compact.

[0101] In some embodiments, the thickness of the adhesive tape 25 ranges from 0.2 mm to 1 mm. For example, the thickness of the adhesive tape 25 ranges from 0.2 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, etc. In this way, the adhesive tape 25 is strong enough and is not easy to break.

[0102] Throughout this specification, reference to terms such as "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0103] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. An electrode assembly, characterized in that: include: First pole piece; a second pole piece, the second pole piece being stacked with the first pole piece along a thickness direction of the first pole piece, and the second pole piece and the first pole piece have opposite polarities; A diaphragm, the diaphragm isolating the first pole piece from the second pole piece and is stacked with the first pole piece along a thickness direction of the first pole piece; The diaphragm, the first pole piece and the second pole piece are wound into one body, and at the starting end and / or the ending end of the winding of the electrode assembly, at least one of the first pole piece and the second pole piece is fixed to the diaphragm through a connector.

2. The electrode assembly according to claim 1, characterized in that: The connector includes colloid, and at least one of the first pole piece and the second pole piece is fixed to the diaphragm through the colloid.

3. The electrode assembly according to claim 2, characterized in that: The colloid bonds the first pole piece and the diaphragm along the thickness direction of the diaphragm, and / or the colloid bonds the second pole piece and the diaphragm along the thickness direction of the diaphragm.

4. The electrode assembly according to claim 3, characterized in that: The colloid is symmetrically arranged with respect to the center of the width direction of the pole piece bonded to the diaphragm.

5. The electrode assembly according to claim 4, characterized in that: The width of the colloid is a first width, the width of the pole piece bonded to the diaphragm is a second width, and the ratio of the first width to the second width is in the range of 0.5-1.

6. The electrode assembly according to claim 3, characterized in that: Along the length direction of the pole piece bonded to the diaphragm, the length of the colloid ranges from 2 mm to 100 mm.

7. The electrode assembly according to claim 3, characterized in that: The thickness of the colloid is less than 20 μm.

8. The electrode assembly according to claim 3, characterized in that: The pole piece bonded to the diaphragm includes a current collector and a coating layer, wherein the coating layer is stacked on the current collector, and a groove away from the current collector is formed at the starting end and / or the ending end of the coating layer winding, and the colloid is at least partially accommodated in the groove.

9. The electrode assembly according to claim 1, characterized in that: There are two diaphragms, one of the first pole piece and the second pole piece is sandwiched between the two diaphragms, and at the starting end and / or the ending end of the winding of the electrode assembly, the two diaphragms are fixed to the sandwiched pole piece through the connector.

10. The electrode assembly according to claim 9, characterized in that: The electrode assembly includes an adhesive tape, and at the starting end and / or the ending end of the winding of the electrode assembly, another electrode sheet except the clamped electrode sheet is connected to the adjacent diaphragm through the adhesive tape.

11. A battery cell, characterized in that: The electrode assembly comprises the electrode assembly according to any one of claims 1 to 10.

12. A battery, characterized in that: The invention comprises a plurality of battery cells as claimed in claim 11.

13. An electrical equipment, characterized in that: Includes the battery cell according to claim 11 or the battery according to claim 12.

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