WO2023137950A1

WO2023137950A1 - Wound-type electrode assembly, battery cell, battery, and electric device

Info

Publication number: WO2023137950A1
Application number: PCT/CN2022/097942
Authority: WO
Inventors: 宋爱利; 陈文伟; 李晓伟; 王巧阁
Original assignee: 江苏时代新能源科技有限公司
Priority date: 2022-01-19
Filing date: 2022-06-09
Publication date: 2023-07-27
Also published as: CN114094288B; CN114094288A

Abstract

The present application belongs to the technical field of battery manufacturing and relates to a wound-type electrode assembly, a battery cell, a battery, and an electric device. The wound-type electrode assembly comprises a first electrode sheet; the first electrode sheet comprises a plurality of first electrode tabs; the plurality of first electrode tabs are stacked once the first electrode sheet is wound; the width of the plurality of first electrode tabs gradually increases from an inner ring to an outer ring of the first electrode sheet; the height of the first electrode tabs (1211) is H1, and the width of a base portion of the first electrode tabs (1211) is L1, where 0.3 < H1/L1 < 1. The service life of the battery cell can be prolonged once the battery cell is assembled.

Description

Winding electrode assembly, battery cell, battery and electrical equipment

Cross References to Related Applications

This application claims the priority of the Chinese patent application 202210057806.9 entitled "Wound Electrode Assembly, Battery Cell, Battery and Electrical Equipment" filed on January 19, 2022, the entire content of which is incorporated herein by reference.

technical field

The present application relates to the technical field of battery manufacturing, in particular, to a wound electrode assembly, a battery cell, a battery and electrical equipment.

Background technique

Energy conservation and emission reduction is the key to the sustainable development of the automobile industry, and electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in its development.

In the development of battery technology, in addition to improving the energy density of batteries, the service life of batteries is also a problem that cannot be ignored. Therefore, how to improve the service life of the battery is a technical problem that needs to be solved urgently in the battery technology.

Contents of the invention

The purpose of the present application is to provide a wound electrode assembly, a battery cell, a battery and an electrical device. After the wound electrode assembly forms a battery cell, the service life of the battery cell can be improved.

The application is achieved through the following technical solutions:

In a first aspect, the present application provides a wound electrode assembly, including a first pole piece, the first pole piece including a plurality of first tabs, the multiple first tabs are stacked after the first pole piece is wound, and the width of the multiple first tabs gradually increases from the inner circle to the outer circle of the first pole piece; the height of the first pole piece is H1, and the width of the root of the first pole piece is L1, which satisfies 0.3<H1/L1<1.

According to the wound electrode assembly of the embodiment of the present application, after the first pole piece is wound, the plurality of first tabs are sequentially stacked from the inner circle to the outer circle of the first pole piece, and the width of the multiple first pole ears gradually increases from the inner circle to the outer circle of the first pole piece. Even if the outer first pole tabs are misaligned during the winding process, the multiple first pole ears still have a large overlapping area in the stacking direction from the inner circle to the outer circle of the first pole piece; when the wound electrode assembly is assembled into a battery cell, the first pole ears need to be connected to the connecting member In order to ensure the connection of each first lug, the connecting member is connected to the first lug in the overlapping area of multiple first lugs. Since the multiple first lugs have a large overlapping area, the influence of the misalignment of the first lug on the connection area can be reduced, and a large connection area between the first lug and the connecting member can be ensured, the connection reliability between the first lug and the connecting member can be improved, the overcurrent capability can be ensured, and the service life of the battery cell can be improved. In addition, the increased width of the first tab can also reduce the probability of the first tab being folded during winding, so as to improve the safety of the battery cell formed by the wound electrode assembly. The relationship between the height of the first tab and the width of the root of the first tab satisfies 0.3<H1/L1<1, which can ensure that the first tab 1211 is not easily folded, and can also ensure that the first tab 1211 does not interfere with other components (such as insulators) to ensure safety. When the height of the first tab is constant, the greater the width of the root of the first tab, the less likely the first tab will be folded during winding, ensuring that the battery cell composed of the wound electrode assembly has higher safety. If the width of the root of the first tab is too large, the first tab is likely to interfere with other components (such as insulators); if the width of the root of the first tab is too small, during the transportation of the first pole piece, the reverse force of the first tab passing the roller is relatively large, and the first tab is easy to fold, and the folded first tab will affect the safety of the battery cell composed of the wound electrode assembly.

According to some embodiments of the present application, among the plurality of first tabs, the projection of the innermost first tab on a preset plane is located within the projection of the outermost first tab on the preset plane, and the preset plane is perpendicular to the stacking direction of the plurality of first tabs.

In the above scheme, among the plurality of first tabs, the projection of the innermost first tab on the preset plane is within the projection of the outermost first tab on the preset plane. Even if the first tab is misaligned during winding, the projection of the innermost first tab on the preset plane is still within the projection of the outermost first tab on the preset plane. It has a larger connection area with the connecting member.

According to some embodiments of the present application, among the two adjacent first tabs, the projection of the inner first tab on the preset plane is located within the projection of the outer first tab on the preset plane.

In the above scheme, among the two adjacent first tabs, the projection of the inner first tab is located within the projection of the outer first tab, so that the overlapping area of any two adjacent first tabs remains unchanged, and the misalignment of the first tabs during winding does not affect the connection area between the multiple first tabs and the connecting member, ensuring high connection reliability between the multiple first tabs and the connecting member.

According to some embodiments of the present application, the width difference between every two adjacent first tabs is equal.

In the above solution, among the plurality of first tabs, any two adjacent first tabs have the same gradual change in width, which is convenient for processing and manufacturing.

According to some embodiments of the present application, the first pole piece further includes a first main body portion, the first tab protrudes from a first edge of the first main body portion, the first tab includes two second edges oppositely disposed along the width direction thereof, and the angle between the second edge and the first edge is R, which satisfies 90°<R<120°.

In the above scheme, the angle R between the second edge and the first edge determines the edge inclination of the first tab, and the above angle range not only ensures that the first tab and the connecting member have a larger connection area, but also ensures that the first tab is not easy to fold. If the included angle R is too small, the first tab is easy to fold; if the included angle R is too large, the connection area between the first tab and the connecting member will be reduced, affecting the connection reliability between the first tab and the connecting member.

According to some embodiments of the present application, the wound electrode assembly further includes a second pole piece opposite in polarity to the first pole piece, the second pole piece includes a plurality of second pole tabs, the multiple second pole tabs are stacked after the second pole piece is wound, and the width of the multiple second pole tabs gradually increases from the inner circle to the outer circle of the second pole piece.

In the above solution, the structure of the second tab of the second pole piece is the same as that of the first tab, so as to ensure the connection reliability between the second tab and another connecting member, thereby improving the service life of the battery cell. The width of the plurality of second tabs gradually increases from the inner ring to the outer ring of the second pole piece, so that the second tabs are not easy to be folded, and the safety of the battery cell is improved.

In a second aspect, the present application provides a battery cell, including: a housing; and the wound electrode assembly in the above embodiment, the wound electrode assembly is disposed in the housing.

According to the battery cell according to the embodiment of the present application, since the width of the first tab of the wound electrode assembly gradually increases from the inner ring to the outer ring in the stacking direction, even if the first tab is misaligned during winding, there is still a relatively large contact area between the multiple first tabs and the connecting member, ensuring the reliability of the connection between the first tab and the connecting member, and improving the service life of the battery cell.

According to some embodiments of the present application, the housing includes a casing and an end cover, the casing has an opening, the wound electrode assembly is disposed in the casing, the end cap is used to cover the opening, and the battery cell further includes: an insulator, disposed between the end cap and the wound electrode assembly, for insulating and isolating the end cap from the first tab; wherein, a first protrusion is provided on a side of the insulating member facing the wound electrode assembly, and the first protrusion abuts against the wound electrode assembly, and the first protrusion is provided with a structure for avoiding the plurality of tabs. The first avoidance part of the first lug.

In the above solution, the first protrusion abuts against the wound electrode assembly, restricting the movement of the wound electrode assembly in the casing, and positioning the wound electrode assembly; the first avoidance part avoids a plurality of first lugs, which can avoid interference between the first lug and the first protrusion, and ensure assembly accuracy.

In a third aspect, the present application provides a battery, which includes the battery cells in the above embodiments.

In a fourth aspect, the present application provides an electric device, which includes the battery in the above embodiment, and the battery is used to provide electric energy.

In a fifth aspect, the present application provides a method for manufacturing a battery cell, which includes: providing a casing; providing a wound electrode assembly, the wound electrode assembly includes a first pole piece, and the first pole piece includes a plurality of first tabs, the multiple first tabs are stacked after the first pole piece is wound, the width of the multiple first tabs gradually increases from the inner circle to the outer circle of the first pole piece, the height of the first tab is H1, and the width of the root of the first tab is L1, satisfying 0.3<H1/L1<1 ; disposing the wound electrode assembly in the shell.

In a sixth aspect, the present application provides a manufacturing device for a battery cell, which includes: providing a module for providing a housing and a wound electrode assembly, the wound electrode assembly includes a first pole piece, the first pole piece includes a plurality of first tabs, the multiple first tabs are stacked after the first pole piece is wound, the width of the multiple first tabs gradually increases from the inner circle to the outer circle of the first pole piece, the height of the first tab is H1, and the width of the root of the first tab is L1, satisfying 0.3<H1/ L1<1; an assembly module, used for disposing the wound electrode assembly in the casing.

The above description is only an overview of the technical solution of the present application. In order to understand the technical means of the present application more clearly, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific implementation methods of the present application are enumerated below.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without creative work.

Fig. 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application;

Figure 2 is an exploded view of a battery provided in some embodiments of the present application;

Fig. 3 is an exploded view of a battery cell provided by some embodiments of the present application;

Fig. 4 is an axonometric view of a wound electrode assembly provided by some embodiments of the present application;

Fig. 5 is a front view of a wound electrode assembly provided by some embodiments of the present application;

Fig. 6 is a top view of a wound electrode assembly provided by some embodiments of the present application;

Fig. 7 is a schematic diagram of the unfolded state of the first pole piece of the wound electrode assembly provided by some embodiments of the present application;

Fig. 8 is a partial schematic diagram of the first pole piece provided by some embodiments of the present application;

Fig. 9 is a schematic diagram of the assembly process of the battery cell provided by some embodiments of the present application;

Fig. 10 is a partial cross-sectional view of a battery cell provided by some embodiments of the present application;

Fig. 11 is a schematic structural diagram of an insulating member provided by some embodiments of the present application;

Fig. 12 is a schematic diagram of the assembly process of the battery cell when the tabs are misaligned according to some embodiments of the present application;

Fig. 13 is a schematic flowchart of a method for manufacturing a battery cell according to some embodiments of the present application;

FIG. 14 is a schematic block diagram of manufacturing equipment for a battery cell 10 according to some embodiments of the present application.

In the drawings, the drawings are not drawn to scale.

Marking description: 100-battery; 101-box; 1011-first part; 1012-second part; 10-battery unit; 11-outer shell; 111-housing; 13-insulator; 131-first protrusion; 1311-first avoiding part; 1312-second avoiding part; 141-first connecting member; 142-second connecting member; 151-first electrode terminal; 152-second electrode terminal; P1-first connecting area; P2-second connecting area;

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the technical field of this application; the terms used in this application in the description of the application are only for the purpose of describing specific embodiments, and are not intended to limit the application; the terms "comprising" and "having" in the description and claims of the application and the description of the above drawings, as well as any variations thereof, are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application or the above drawings are used to distinguish different objects, rather than to describe a specific sequence or primary-subordinate relationship.

Reference in this application to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

In the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", "connection" and "attachment" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediary, or an internal connection between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

The term "and/or" in this application is only an association relationship describing associated objects, which means that there may be three relationships, for example, A and/or B may mean: there is A, A and B exist at the same time, and B exists. In addition, the character "/" in this application generally indicates that the contextual objects are an "or" relationship.

"Multiple" in this application refers to more than two (including two), similarly, "multiple groups" refers to more than two groups (including two), and "multiple pieces" refers to more than two (including two).

In this application, reference to a battery refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack, and the like.

The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive pole piece, a negative pole piece and a diaphragm. A battery cell works primarily by moving metal ions between the positive and negative pole pieces. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode current collector that has been coated with the positive electrode active material layer. The positive electrode current collector that is not coated with the positive electrode active material layer serves as the positive electrode lug. Taking a lithium-ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode current collector that has been coated with the negative electrode active material layer. The negative electrode current collector that is not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon. In order to ensure that a large current is passed without fusing, the number of positive pole tabs is multiple and stacked together, and the number of negative pole tabs is multiple and stacked together. The material of the diaphragm can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc. The electrode assembly mentioned in the embodiment of the present application has a wound structure.

The battery cell also includes a connecting member, or also called a current collecting member, for electrical connection with the tab of the electrode assembly.

At present, judging from the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydraulic, thermal, wind and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, as well as military equipment and aerospace and other fields. With the continuous expansion of power battery application fields, its market demand is also constantly expanding.

The development of battery technology should consider many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the reliability of the battery also needs to be considered.

For a battery cell, the main reliability factor is the connection reliability between the tabs of the electrode assembly and the connecting member. In order to ensure the reliability of the connection between the tab and the connecting member, usually the tab and the connecting member are welded. However, the inventors found that the multiple tabs of the wound electrode assembly are prone to dislocation after winding, and the dislocated multiple tabs and the connecting member have a small connection area, making the connection reliability between the tabs and the connecting member poor. Specifically, when multiple tabs and connecting members are welded, if you want to ensure that each tab is welded, you need to overlap multiple tabs and weld the connecting member to the overlapping area of multiple tabs. Since the tabs are easily misplaced during winding, the overlapping area of multiple tabs is small, resulting in a small welding area.

In view of this, in order to solve the problem of poor connection reliability between tabs and connecting members, the inventors designed a wound electrode assembly after in-depth research. The wound electrode assembly includes a first pole piece. The first pole piece includes a plurality of first tabs. The multiple first tabs are stacked after the first pole piece is wound. The width of the multiple first tabs gradually increases from the inner circle to the outer circle of the first pole piece. By increasing the width of the outer first tab to compensate for the misalignment of the outer first tab, it is ensured that a plurality of first tabs have a larger overlapping area.

In a battery cell composed of such a wound electrode assembly, even if the outer first tab is dislocated during the winding process, the multiple first tabs also have a large overlapping area. During the battery cell assembly process, the connecting member is connected to the overlapping area of the multiple first tabs to reduce the impact of the dislocation of the first tab on the connection area, ensure a large connection area between the first tab and the connecting member, improve the connection reliability between the first tab and the connecting member, and ensure the overcurrent capability, thereby improving the service life of the battery cell. In addition, the increased width of the first tab can also reduce the probability of the first tab being folded during winding, so as to improve the safety of the battery cell formed by the wound electrode assembly.

The battery cells disclosed in the embodiments of the present application can be used, but not limited, in electrical equipment such as vehicles, ships, or aircrafts. The power supply system of the electrical equipment can be composed of the battery cells and batteries disclosed in this application.

The embodiment of the present application provides an electric device using a battery as a power source. The electric device can be, but not limited to, a mobile phone, a tablet computer, a notebook computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, a spacecraft, and the like. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, spaceships, etc.

In the following embodiments, for the convenience of description, a vehicle 1000 as an electric device according to an embodiment of the present application is taken as an example.

Please refer to FIG. 1 , which is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle. The interior of the vehicle 1000 is provided with a battery 100 , and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000 . The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as an operating power source of the vehicle 1000, and can be used for a circuit system of the vehicle, for example, for starting, navigating, and working power requirements of the vehicle.

The vehicle 1000 may further 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, for starting, navigating, and working power requirements of the vehicle 1000 during driving.

In some embodiments of the present application, the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel oil or natural gas to provide driving power for the vehicle 1000 .

Please refer to FIG. 2 , which is an exploded view of a battery 100 provided by some embodiments of the present application. The battery 100 includes a case 101 and a battery cell 10 housed in the case 101 . Wherein, the box body 101 is used to provide accommodating space for the battery cells 10 , and the box body 101 can adopt various structures. In some embodiments, the box body 101 may include a first part 1011 and a second part 1012 , the first part 1011 and the second part 1012 cover each other, and the first part 1011 and the second part 1012 jointly define an accommodation space for accommodating the battery cell 10 . The second part 1012 can be a hollow structure with one end open, the first part 1011 can be a plate-shaped structure, and the first part 1011 covers the opening side of the second part 1012, so that the first part 1011 and the second part 1012 jointly define an accommodation space; Certainly, the box body 101 formed by the first part 1011 and the second part 1012 may be in various shapes, such as a cylinder, a cuboid, and the like.

In the battery 100 , there may be multiple battery cells 10 , and the multiple battery cells 10 may be connected in series, in parallel or in parallel. The mixed connection means that the multiple battery cells 10 are connected in series and in parallel. A plurality of battery cells 10 can be directly connected in series or in parallel or mixed together, and then the whole formed by the plurality of battery cells 10 can be accommodated in the box body 101; The battery 100 may also include other structures, for example, the battery 100 may also include a current flow component for realizing electrical connection between a plurality of battery cells 10 .

Wherein, each battery cell 10 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but not limited thereto. The battery cell 10 provided in the embodiment of the present application is in the shape of a cube.

Please refer to FIG. 3 , which is an exploded view of a battery cell 10 provided by some embodiments of the present application. The battery cell 10 refers to the smallest unit constituting the battery 100 . As shown in FIG. 3 , the battery cell 10 includes a casing 11 , a wound electrode assembly 12 , connecting members and other functional components.

The casing 11 is a component used to form the internal environment of the battery cell 10 , and the formed internal environment can be used to accommodate the wound electrode assembly 12 , electrolyte and other components. The housing 11 may include a housing 111 and an end cover 112. The housing 111 and the end cover 112 may be independent components, or an opening may be provided on the housing 111, and the internal environment of the battery cell 10 is formed by making the end cover 112 cover the opening at the opening. Without limitation, the end cover 112 and the housing 111 can also be integrated. Specifically, the end cover 112 and the housing 111 can form a common connection surface before other components are inserted into the housing. The housing 111 may be in the shape of a cuboid. Specifically, the shape of the casing 111 can be determined according to the specific shape and size of the wound electrode assembly 12 . The housing 111 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which are not particularly limited in this embodiment of the present application.

The end cap 112 refers to a component that covers the opening of the casing 111 to isolate the internal environment of the battery cell 10 from the external environment. Without limitation, the shape of the end cap 112 can be adapted to the shape of the housing 111 to fit the housing 111 . Optionally, the end cap 112 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 112 is not easily deformed when being squeezed and collided, so that the battery cell 10 can have higher structural strength, and the safety performance can also be improved. Functional components such as electrode terminals may be provided on the end cap 112 . The electrode terminal can be used for electrical connection with the wound electrode assembly 12 for outputting or inputting electric energy of the battery cell 10 . In some embodiments, the end cover 112 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold value. The material of the end cap 112 may also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application. In some embodiments, an insulator can be provided inside the end cover 112 , and the insulator can be used to isolate the electrical connection components in the housing 111 from the end cover 112 to reduce the risk of short circuit. Exemplarily, the insulating member may be plastic, rubber or the like.

The wound electrode assembly 12 is a component in the battery cell 10 where the electrochemical reaction occurs. The case 111 may contain one or more wound electrode assemblies 12 . In the implementation of the present application, the wound electrode assembly 12 is mainly formed by winding a positive pole piece and a negative pole piece, and a separator is usually provided between the positive pole piece and the negative pole piece. The portion of the positive pole piece and the negative pole piece with the active material constitutes the main body of the wound electrode assembly 12 , and the portions of the positive pole piece and the negative pole piece without the active material respectively constitute tabs. The positive pole tab and the negative pole tab can be located at one end of the main body together or at two ends of the main body respectively. During the charging and discharging process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to the electrode lead-out parts (such as electrode terminals, housing 111 ) to form a current loop.

The connecting member is a conductive piece used to connect the tab and the electrode lead-out part, so as to realize the electrical connection between the tab and the electrode lead-out part.

According to some embodiments of the present application, see FIG. 4 to FIG. 7, FIG. 4 is an isometric view of the wound electrode assembly 12 provided by some embodiments of the present application, FIG. 5 is a front view of the wound electrode assembly 12 provided by some embodiments of the present application, FIG. 6 is a top view of the wound electrode assembly 12 provided by some embodiments of the present application, and FIG. 7 is a schematic diagram of the unfolded state of the first pole piece 121 of the wound electrode assembly 12 provided by some embodiments of the present application. The present application provides a wound electrode assembly 12. As shown in FIGS. 4 to 7, the wound electrode assembly 12 includes a first pole piece 121. The first pole piece 121 includes a plurality of first tabs 1211. The multiple first tabs 1211 are stacked after the first pole piece 121 is wound. The width of the multiple first tabs 1211 gradually increases from the inner circle to the outer circle of the first pole piece 121.

The first pole piece 121 is a component of the wound electrode assembly 12 . The first pole piece 121 includes a first current collector and a first active material layer, the first active material layer is coated on the surface of the first current collector, the first current collector not coated with the first active material layer protrudes from the first current collector coated with the first active material layer, and the first current collector not coated with the first active material layer serves as a first tab 1211. The first pole piece 121 may be a positive pole piece or a negative pole piece. When the first pole piece 121 is a positive pole piece, the first pole tab 1211 is a positive pole tab; when the first pole piece 121 is a negative pole piece, the first pole tab 1211 is a negative pole tab.

The first pole piece 121 includes a plurality of first pole lugs 1211 , and during the winding process of the first pole piece 121 , at least one first pole piece 121 is provided for each circle of the first pole piece 121 . The multiple first tabs 1211 are stacked after the first pole piece 121 is wound, that is, the multiple first tabs 1211 are sequentially stacked along the thickness direction of the wound electrode assembly 12 .

In the figure, the dimension indicated by the letter L is the width of the first tab 1211 , the direction indicated by the letter X is the length direction of the first pole piece 121 , and the direction indicated by the letter Y is the thickness direction of the wound electrode assembly 12 . As shown in FIGS. 6 and 7 , the width L of the first tab 1211 refers to the dimension of the first tab 1211 in the length direction X of the first pole piece 121, for example, along the length direction X of the first pole piece 121, at the same position on one edge of the first tab 1211, the distance from one side of the first tab 1211 to the other side of the first tab 1211.

The widths of the plurality of first tabs 1211 gradually increase from the inner circle to the outer circle of the first pole piece 121. That is, as shown in FIG.

According to the wound electrode assembly 12 of the embodiment of the present application, multiple first tabs 1211 are stacked after the first pole piece 121 is wound, and the width of the multiple first tabs 1211 gradually increases from the inner circle to the outer circle of the first pole piece 121. Even if the outer first pole piece 1211 is misaligned during the winding process, the multiple first pole tabs 1211 also have a large overlapping area in the stacking direction from the inner circle to the outer circle of the first pole piece 121; when the wound electrode assembly 12 When the battery cell 10 is assembled, because the plurality of first tabs 1211 have a large overlapping area, the influence of the dislocation of the first tabs 1211 on the connection area can be reduced, and the connection area between the first tab 1211 and the connecting member can be ensured, the connection reliability between the first tab 1211 and the connecting member can be improved, and the overcurrent capability can also be ensured, thereby improving the service life of the battery cell 10. In addition, the increased width of the first tab 1211 can also reduce the probability of the first tab 1211 being folded during winding, so as to improve the safety of the battery cell 10 formed by the wound electrode assembly 12 .

According to some embodiments of the present application, optionally, as shown in FIG. 5 and FIG. 6 , among the plurality of first tabs 1211 , the projection of the innermost first tab 1211 on a preset plane is within the projection of the outermost first tab 1211 on a preset plane, and the preset plane is perpendicular to the stacking direction of the plurality of first tabs 1211 .

The preset plane is a plane perpendicular to the stacking direction of the plurality of first tabs 1211 , which is a reference plane for comparing the overlapping of the plurality of first tabs 1211 .

The innermost first tab 1211 and the outermost first tab 1211 refer to the direction from the inner circle of the wound first pole piece 121 to the outer circle in the stacking direction of the plurality of first pole tabs 1211, the innermost first pole piece 1211 is closer to the innermost circle of the first pole piece 121 than the outermost first pole piece 1211, and the outermost first pole piece 1211 is closer to the first pole piece 12 than the innermost first pole piece 1211. 1's outermost circle.

The projection of the innermost first tab 1211 on the preset plane is located within the projection of the outermost first tab 1211 on the preset plane, that is, along the stacking direction of the plurality of first tabs 1211, on the preset plane, the projection of the innermost first tab 1211 and the projection of the outermost first tab 1211 have the largest overlapping area.

In this case, during the winding process of the first pole piece 121, even if the outermost first tab 1211 is displaced, after the winding is completed, when multiple first tabs 1211 are stacked, the projection of the innermost first tab 1211 on the preset plane is still within the projection of the outermost first tab 1211 on the preset plane, and the overlapping area between the innermost first tab 1211 and the outermost first tab 1211 will not change, ensuring that the innermost first tab 1211 Both the 211 and the outermost first tab 1211 can be connected to the connecting member, thereby ensuring that the plurality of first tabs 1211 and the connecting member have a larger connection area.

According to some embodiments of the present application, optionally, among two adjacent first tabs 1211 , the projection of the inner first tab 1211 on the preset plane is located within the projection of the outer first tab 1211 on the preset plane.

The inner first tab 1211 and the outer first tab 1211 refer to the two first tabs 1211 in the direction from the inner circle to the outer circle of the first pole piece 121 , the inner first pole ear 1211 is close to the inner circle of the first pole piece 121 , and the outer first pole lug 1211 is close to the outer circle of the first pole piece 121 .

Among the two adjacent first tabs 1211, the projection of the inner first tab 1211 on the preset plane is within the projection of the outer first tab 1211 on the preset plane, that is, the overlapping area of any two adjacent first tabs 1211 remains unchanged, and the error of the first tab 1211 during winding does not affect the connection area between the multiple first tabs 1211 and the connecting member, ensuring that the multiple first tabs 1211 and the connecting member have high connection reliability.

According to some embodiments of the present application, optionally, the width difference between every two adjacent first tabs 1211 is equal.

The width difference between every two adjacent first tabs 1211 is equal, that is, along the stacking direction of the multiple first tabs 1211, the increasing trend of the width of the multiple first tabs 1211 from the inner ring to the outer ring of the first pole piece 121 is an arithmetic sequence, for example, along the stacking direction of the multiple first tabs 1211, the width difference between the second first tab 1211 and the first first tab 1211 is n, the third first tab 1211 and the second first tab 1211 The width difference of 211 is also n, and the width difference between the mth first tab 1211 and the m-1th first tab 1211 is also n, where m is greater than 3, such as m is 4, 5, 6, 7, etc.

Among the plurality of first tabs 1211 , any two adjacent first tabs 1211 have the same gradual change in width, which is convenient for manufacturing.

Please refer to FIG. 8 , which is a partial schematic diagram of the first pole piece 121 provided by some embodiments of the present application. According to some embodiments of the present application, optionally, the height of the first tab 1211 is H1, and the width of the root of the first tab 1211 is L1, satisfying 0.3<H1/L1<1.

In the figure, the direction indicated by the letter Z is the width direction of the first pole piece 121 . The height H1 of the first tab 1211 refers to the dimension of the first tab 1211 in the width direction Z of the first pole piece 121 during the forming process of the first pole piece 121 .

The first pole piece 121 also includes a first main body portion 1212, the first pole lug 1211 is connected to the first main body portion 1212, and the root of the first pole lug 1211 refers to the part of the first pole lug 1211 used to connect with the first main body portion 1212, that is, the end of the first pole lug 1211 away from the connecting member. The width L1 of the root of the first tab 1211 refers to the dimension of the root of the first tab 1211 in the length direction of the first pole piece 121 .

The relationship between the height H1 of the first tab 1211 and the width L1 of the root of the first tab 1211 satisfies 0.3<H1/L1<1, which can ensure that the first tab 1211 is not easily folded, and can also ensure that the first tab 1211 does not interfere with other components (such as insulators). When the height H1 of the first tab 1211 is constant, the larger the width L1 of the root of the first tab 1211 is, the reverse force of the first tab 1211 passing over the roller during the conveying process of the first pole piece 121 can be reduced, and the first tab 1211 is less likely to be folded, ensuring that the battery cell 10 composed of the wound electrode assembly 12 has higher safety. If the width L1 of the root of the first tab 1211 is too large, the first tab 1211 is likely to interfere with other components (such as insulators); if the width L1 of the root of the first tab 1211 is too small, the reverse force of the first tab 1211 passing the roller is large, and the first tab 1211 is easy to fold, which affects the safety of the battery cell 10 formed by the wound electrode assembly 12.

Optionally, the relationship between the height H1 of the first tab 1211 and the width L1 of the root of the first tab 1211 satisfies 0.4<H1/L1<0.7.

According to some embodiments of the present application, optionally, as shown in FIG. 8 , the first pole piece 121 further includes a first main body portion 1212 , the first tab 1211 protrudes from the first edge 1213 of the first main body 1212 , the first tab 1211 includes two second edges 1214 oppositely arranged along its width direction, and the angle between the second edge 1214 and the first edge 1213 is R, which satisfies 90°<R<120°.

The first tab 1211 protrudes from the first edge 1213 of the first main body 1212. During the forming process of the first pole piece 121, a die-cutting device (such as blade, laser, etc.) cuts the first pole piece 121 to form the first pole piece 1211, and the first edge 1213 is a cutting edge.

The two second edges 1214 are oppositely arranged along the width direction of the first tab 1211 , and the second edges 1214 are also cutting edges.

The angle R between the second edge 1214 and the first edge 1213 determines the edge inclination of the first tab 1211, and the angle R between the second edge 1214 and the first edge 1213 satisfies 90°<R<120°, which not only ensures that the first tab 1211 has a larger connection area with the connecting member, but also ensures that the first tab 1211 is not easily folded. If the angle R between the second edge 1214 and the first edge 1213 is too small, the first tab 1211 is easy to fold; if the angle R between the second edge 1214 and the first edge 1213 is too large, the connection area between the first tab 1211 and the connecting member is reduced, which affects the connection reliability between the first tab 1211 and the connecting member.

Optionally, the angle R between the second edge 1214 and the first edge 1213 satisfies 100°<R<110°.

According to some embodiments of the present application, optionally, as shown in FIG. 4 , the wound electrode assembly 12 further includes a second pole piece 122 opposite in polarity to the first pole piece 121 . The second pole piece 122 includes a plurality of second pole tabs 1221 , and the multiple second pole tabs 1221 are stacked after the second pole piece 122 is wound.

The second pole piece 122 is a conductive member with opposite polarity to that of the first pole piece 121 , and the structure of the second pole piece 122 refers to the structure of the first pole piece 121 .

The structure of the second tab 1221 is the same as that of the first tab 1211 , which ensures the reliability of the connection between the second tab 1221 and another connecting member, thereby improving the service life of the battery cell 10 . The width of the plurality of second tabs 1221 gradually increases from the inner ring to the outer ring of the second pole piece 122 , so that the second tabs 1221 are not easy to be folded, and the safety of the battery cell 10 is improved.

The second pole piece 122 also includes a second body part, and the second pole lug 1221 protrudes from the second body part, and its structural form is the same as that of the first pole lug protruding from the first body part 1212 .

According to some embodiments of the present application, the present application also provides a battery cell 10 , the battery cell 10 includes a casing 11 , and the wound electrode assembly 12 described in any of the above solutions, and the wound electrode assembly 12 is disposed in the casing 11 .

The casing 11 is a hollow part, and its interior is used to accommodate the electrode assembly to protect the electrode assembly.

According to the battery cell 10 of the embodiment of the present application, since the width of the first tab 1211 of the wound electrode assembly 12 gradually increases from the inner ring to the outer ring in the stacking direction, even if the first tab 1211 is misaligned during winding, there is still a relatively large contact area between the plurality of first tabs 1211 and the connecting member, ensuring the reliability of the connection between the first tab 1211 and the connecting member, and improving the service life of the battery cell 10 .

According to some embodiments of the present application, optionally, as shown in FIG. 3 , the wound electrode assembly 12 further includes a second pole piece 122 , and the second pole piece 122 includes a plurality of second pole tabs 1221 . The battery cell 10 further includes a first electrode terminal 151 , a second electrode terminal 152 , a first connecting member 141 and a second connecting member 142 , the first electrode terminal 151 and the second electrode terminal 152 are both disposed on the end cap 112 ; the first tab 1211 is electrically connected to the first electrode terminal 151 through the first connecting member 141 , and the second tab 1221 is electrically connected to the second electrode terminal 152 through the second connecting member 142 . The first electrode terminal 151 and the second electrode terminal 152 are electrode lead-out parts.

Please refer to FIGS. 9-11. FIG. 9 is a schematic diagram of the assembly process of the battery cell 10 provided by some embodiments of the present application. FIG. 9 shows a schematic diagram of the state where the tab is connected to the connecting member. In the figure, the first tab 1211 is connected to the first connecting member 141, and the second tab 1221 is connected to the second connecting member 142. At this time, the wound electrode assembly 12 has not been placed in the casing 11; FIG. 10 is a partial cross-sectional view of the battery cell 10 provided by some embodiments of the present application, and FIG. 11 is some embodiments of the present application A schematic diagram of the structure of the insulating member 13 is provided.

According to some embodiments of the present application, optionally, as shown in FIG. 3 , the housing 11 includes a casing 111 and an end cover 112 . The casing 111 has an opening, and the wound electrode assembly 12 is disposed in the casing 111 ; the end cap 112 is used to cover the opening. As shown in FIG. 3 and FIGS. 9-11 , the battery cell 10 further includes an insulator 13 disposed between the end cap 112 and the wound electrode assembly 12 , and the insulator 13 is used to insulate and isolate the end cap 112 from the first tab 1211 . Wherein, the side of the insulator 13 facing the wound electrode assembly 12 is provided with a first protrusion 131 , the first protrusion 131 abuts against the wound electrode assembly 12 , and the first protrusion 131 is provided with a first escape portion 1311 for avoiding a plurality of first tabs 1211 .

The casing 111 is a hollow structure, and the opening communicates with the inner space of the casing 111 , so that the wound electrode assembly 12 enters the inside of the casing 111 .

The end cap 112 covers the opening and is sealed with the casing 111 , so that the inside of the casing 11 is a closed chamber, preventing electrolyte leakage or dust from entering the casing 11 .

The insulating member 13 is an electrically insulating component, such as rubber or plastic (such as PET (Polyethylene terephthalate, polyethylene terephthalate), PP (polypropylene, polypropylene) and the like).

In some embodiments, the insulator 13 is rectangular, the width direction of the insulator 13 corresponds to the thickness direction Y of the wound electrode assembly 12 , and the first protrusion 131 extends along the width direction of the insulator 13 .

The first protrusion 131 is located on the side of the insulator 13 facing the wound electrode assembly 12, that is, the first protrusion 131 protrudes from the surface of the insulator 13 facing the wound electrode assembly 12, and the first protrusion 131 is closer to the wound electrode assembly 12 relative to the surface.

There are multiple wound electrode assemblies 12, and the lugs of each wound electrode assembly 12 are located on the same side of the wound electrode assembly 12. For example, as shown in FIG. 3, FIG. 9 and FIG. 12 extends in the thickness direction Y, as shown in FIG. 11 , the first protrusion 131 has two first avoiding portions 1311, and the two first avoiding portions 1311 are located at both ends of the first protrusion 131 along the width direction of the insulator 13, and the two first avoiding portions 1311 are respectively used to avoid the first tabs 1211 of the two electrode assemblies.

The first protrusion 131 abuts against the wound electrode assembly 12, restricting the movement of the wound electrode assembly 12 in the housing 111, and positioning the wound electrode assembly 12; the first avoidance portion 1311 avoids a plurality of first tabs 1211, which can avoid interference between the first tab 1211 and the first protrusion 131, and ensure assembly accuracy.

According to some embodiments of the present application, optionally, in an embodiment where the wound electrode assembly 12 further includes a second pole piece 122, as shown in FIGS.

The second escape portion 1312 and the first avoidance portion 1311 are distributed on both sides of the first protrusion 131 along the length direction of the insulating member 13 , that is, along the length direction of the insulating member 13 , the first tab 1211 and the second tab 1221 are distributed on both sides of the first protrusion 131 .

By avoiding the plurality of second pole lugs 1221 by the second escape portion 1312 , the interference between the second pole lug 1221 and the first protrusion 131 can be avoided, and the assembly accuracy can be ensured.

According to some embodiments of the present application, optionally, as shown in FIG. 11 , the side of the insulator 13 facing the wound electrode assembly 12 is further provided with second protrusions 132, and the second protrusions 132 are distributed at both ends of the insulator 13 in the length direction, and the second protrusions 132 are used to abut against the wound electrode assembly 12. In other words, the second protrusions 132 are distributed on two edges of the insulating member 13 in the length direction.

Please refer to FIG. 12 . FIG. 12 is a schematic diagram of the assembly process of the battery cell 10 when tabs are dislocated according to some embodiments of the present application. For ease of reference, FIG. 12 only shows a part of the structure of the battery cell 10 . In the battery cell 10 of the embodiment of the present application, when the wound electrode assembly 12 is wound, after the first tab 1211 of the first pole piece 121 and the second tab 1221 of the second pole piece 122 are misaligned, when the wound electrode assembly 12 is connected and assembled with the connection member, the first connection area P1 of the plurality of first tabs 1211 and the first connection member 141 can completely cover each first tab 1211, and the plurality of second tabs 1221 and the second connection member 142 The second connection area P2 can completely cover each second tab 1221 .

According to some embodiments of the present application, the present application also provides a battery, which includes the battery cell 10 described in any of the above schemes.

According to some embodiments of the present application, the present application also provides an electric device, which includes the battery described in any one of the solutions above, and the battery is used to provide electric energy for the electric device.

The powered device may be any of the aforementioned devices or systems using batteries.

According to some embodiments of the present application, referring to FIGS. 3 to 12 , the present application provides a battery cell 10 , which includes a wound electrode assembly 12 , a first connecting member 141 and a second connecting member 142 . The wound electrode assembly 12 includes a first pole piece 121 , a second pole piece 122 and a separator disposed between the first pole piece 121 and the second pole piece 122 . The first pole piece 121 includes a plurality of first tabs 1211, which are stacked after the first pole piece 121 is wound, and the width of the multiple first tabs 1211 gradually increases from the inner circle to the outer circle of the first pole piece 121; Gradually increase to the outer circle. After winding, no matter whether the first tab 1211 of the outer ring is misaligned, the multiple first tabs 1211 have a larger overlapping area, so that the multiple first tabs 1211 and the first connecting member 141 have a larger connection area, ensuring the reliability of the connection between the multiple first tabs 1211 and the first connecting member 141; similarly, regardless of whether the second tab 1221 of the outer ring is misaligned, the multiple second tabs 1221 have a larger overlapping area, so that the multiple second tabs 122 1 and the second connection member 142 have a larger connection area, ensuring the connection reliability between the plurality of second tabs 1221 and the second connection member 142 . The connection between the wound electrode assembly 12 of the battery cell 10 and the connecting member is stable and reliable, not easily damaged, and has a long service life.

FIG. 13 shows a schematic flowchart of a method for manufacturing a battery cell 10 according to some embodiments of the present application. As shown in FIG. 13 , the manufacturing method of the battery cell 10 may include:

401, provide the casing 11;

402. Provide a wound electrode assembly 12. The wound electrode assembly 12 includes a first pole piece 121. The first pole piece 121 includes a plurality of first tabs 1211. The multiple first tabs 1211 are stacked after the first pole piece 121 is wound. The width of the multiple first tabs 1211 gradually increases from the inner circle to the outer circle of the first pole piece 121. The height of the first pole piece 1211 is H1, and the width of the root of the first pole piece 1211 is L1. Satisfy 0.3<H1/L1<1;

403 , disposing the wound electrode assembly 12 in the casing 11 .

It should be pointed out that step "401, providing the shell 11" and step "402, providing the wound electrode assembly 12" are parallel steps, and the order of providing the two is not limited. For example, step "401, providing the shell 11" can be performed first, and then step "402, providing the wound electrode assembly 12" can be performed; or, step "402, providing the wound electrode assembly 12" can be performed first, and then step "401, providing the shell 11" can be performed.

FIG. 14 shows a schematic block diagram of the manufacturing equipment of the battery cell 10 according to some embodiments of the present application. As shown in FIG. 14 , the manufacturing equipment of the battery cell 10 may include a providing module 501 and an assembling module 502 . The module 501 is used to provide the housing 11 and the wound electrode assembly 12. The wound electrode assembly 12 includes a first pole piece 121, and the first pole piece 121 includes a plurality of first tabs 1211. The plurality of first tabs 1211 are stacked after the first pole piece 121 is wound. The width of the multiple first tabs 1211 gradually increases from the inner circle to the outer circle of the first pole piece 121. The width of the portion is L1 and satisfies 0.3<H1/L1<1. The assembly module 502 is used for disposing the wound electrode assembly 12 in the casing 11 .

While the application has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A wound electrode assembly, characterized in that it includes a first pole piece, the first pole piece includes a plurality of first tabs, the plurality of first tabs are stacked after the first pole piece is wound, and the width of the plurality of first tabs gradually increases from the inner circle to the outer circle of the first pole piece;

The height of the first tab is H1, and the width of the root of the first tab is L1, which satisfies 0.3<H1/L1<1.
The wound electrode assembly according to claim 1, wherein, among the plurality of first tabs, the projection of the innermost first tab on a preset plane is located within the projection of the outermost first tab on the preset plane, and the preset plane is perpendicular to the stacking direction of the plurality of first tabs.
The wound electrode assembly according to claim 2, wherein, among the two adjacent first tabs, the projection of the inner first tab on the preset plane is within the projection of the outer first tab on the preset plane.
The wound electrode assembly according to any one of claims 1-3, wherein the width difference between every two adjacent first tabs is equal.
The wound electrode assembly according to any one of claims 1-4, wherein the first pole piece further includes a first main body, the first tab protrudes from a first edge of the first main body, the first tab includes two second edges oppositely arranged along its width direction, the angle between the second edge and the first edge is R, and satisfies 90°<R<120°.
The wound electrode assembly according to any one of claims 1-5, wherein the wound electrode assembly further comprises a second pole piece opposite in polarity to the first pole piece, the second pole piece includes a plurality of second tabs, the plurality of second tabs are stacked after the second pole piece is wound, and the width of the plurality of second tabs gradually increases from the inner circle to the outer circle of the second pole piece.
A battery cell, characterized in that it comprises:

casing; and

The wound electrode assembly according to any one of claims 1-6, the wound electrode assembly is arranged in the casing.
The battery cell according to claim 7, wherein:

The casing includes a casing and an end cover, the casing has an opening, the wound electrode assembly is disposed in the casing, the end cover is used to cover the opening, and the battery cell further includes:

an insulator, disposed between the end cap and the wound electrode assembly, for insulating and isolating the end cap from the first tab;

Wherein, a side of the insulator facing the wound electrode assembly is provided with a first protrusion, the first protrusion abuts against the wound electrode assembly, and the first protrusion is provided with a first escape portion for avoiding the plurality of first tabs.
A battery, characterized by comprising the battery cell according to any one of claims 7-8.
An electric device, characterized by comprising the battery according to claim 9, the battery is used to provide electric energy.
A method for manufacturing a battery cell, comprising:

Provide the enclosure;

Provide a wound electrode assembly, the wound electrode assembly includes a first pole piece, the first pole piece includes a plurality of first tabs, the multiple first tabs are stacked after the first pole piece is wound, the width of the multiple first tabs gradually increases from the inner ring to the outer ring of the first pole piece, the height of the first tab is H1, and the width of the root of the first tab is L1, satisfying 0.3<H1/L1<1;

The wound electrode assembly is arranged in the casing.
A battery cell manufacturing equipment, characterized by comprising:

Provide a module for providing a casing and providing a wound electrode assembly, the wound electrode assembly includes a first pole piece, the first pole piece includes a plurality of first tabs, the multiple first tabs are stacked after the first pole piece is wound, the width of the multiple first tabs gradually increases from the inner circle to the outer circle of the first pole piece, the height of the first tab is H1, and the width of the root of the first tab is L1, satisfying 0.3<H1/L1<1;

An assembly module is used for disposing the wound electrode assembly in the casing.