WO2024016491A1 - Electrode sheet, electrode assembly, battery cell, battery and electric apparatus - Google Patents

Abstract

Provided in the present application are an electrode sheet, an electrode assembly, a battery cell, a battery and an electric apparatus. The electrode sheet comprises a main body portion, the main body portion comprising a base material; and tabs which are connected to the base material, the tabs comprising a plurality of foil materials which are arranged in a stacked manner in the thickness direction of the electrode sheet, and the thickness of the tabs being greater than the thickness of the base material. In the technical solution of the present application, the tabs having multiple layers of foil materials effectively fill the gap between every two adjacent electrode sheets, thereby effectively avoiding the problem of main body portions being melt through during laser welding, and helping to ensure the safety of batteries. Meanwhile, during welding of tabs to adaptors or to other electric energy current flow-through members or to other busbar members, pretreatments such as flattening and stacking are not needed for tabs, so that the assembling process of battery cells is effectively simplified, and waste of the production time caused by a high tab flattening fault rate is avoided, thus effectively improving the production efficiency of batteries.

Description

Pole pieces, electrode components, battery cells, batteries and electrical devices

Cross-references to related applications

This application claims priority to the Chinese patent application (202221877066.5) titled "Pole Pieces, Electrode Assemblies, Battery Cells, Batteries and Electrical Devices" submitted on July 21, 2022. The entire content of this application is incorporated by reference. into this article.

Technical field

The present application relates to the field of battery technology, and in particular to a pole piece, an electrode assembly, a battery cell, a battery and an electrical device.

Background technique

Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. 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 related to their development.

In battery technology, how to improve battery production efficiency while ensuring battery safety is an urgent problem to be solved.

Contents of the invention

This application provides a pole piece, electrode assembly, battery cell, battery and electrical device, which can effectively improve the production efficiency of the battery while ensuring the safety of the battery.

In a first aspect, the application provides a pole piece, including: a main body part including a base material; and pole tabs connected to the base material. The pole tabs comprise a plurality of foil materials stacked along the thickness direction of the pole piece. The thickness of the ears is greater than the thickness of the base material.

In the technical solution of this application, the pole tab of the pole piece includes multiple foil materials stacked along the thickness direction of the pole piece. The overall thickness of the pole tab formed by the multi-layer foil materials is greater than the thickness of the base material. After the pole piece is formed into the electrode assembly, The multi-layer foil tabs effectively fill the gap between two adjacent layers of pole pieces, thereby effectively preventing the problem of welding through the main body during laser welding. At the same time, the multi-layer foil tabs effectively increase the welding end surface of the tabs. The welding area can effectively prevent the problem of false welding during laser welding, further effectively improve the welding stability, and help ensure the safety of the battery; furthermore, because the multi-layer foil tabs effectively increase the welding area of the welding end face of the tabs , so when welding the tabs to adapters or other power overcurrent and busing components, there is no need to perform pre-processing such as flattening or stacking the tabs, thus effectively simplifying the assembly process of the battery cells and avoiding rubbing of the tabs. This eliminates the waste of production time caused by high failure rates, thereby effectively improving battery production efficiency.

According to some embodiments of the present application, the thickness of the tab is greater than the thickness of the main body.

In the above technical solution, the thickness of the pole tab is greater than the thickness of the main body area of the pole piece. After the pole pieces are rolled or stacked into a multi-layer structure, it can effectively ensure that the pole tab can more fully fill the gap between two adjacent layers of pole pieces. , reducing the risk of laser penetrating into the main body through the gap between the tabs of the two layers of pole pieces, thereby effectively ensuring the safety of the battery.

According to some embodiments of the present application, multiple foils are welded to each other to form a welding zone.

In the above technical solution, multiple foils are welded to each other to form a welding zone. The welding zone formed by welding can further thicken the thickness of the tab. In this way, the thickness requirement of the tab can be achieved by welding a smaller number of foils to each other. It is beneficial to save foil and reduce the weight of the tab; at the same time, multiple foils are welded to each other, which can effectively improve the overall structural strength and stability of the tab, thereby reducing the bending and bending of the tab during the winding and lamination process of the pole piece. Risk of deformation such as warping.

According to some embodiments of the present application, the welding area includes multiple rows of sub-welding areas, the multiple rows of sub-welding areas are arranged along the width direction of the pole piece, and each row of sub-welding areas includes multiple sub-welding areas spaced apart along the length direction of the pole piece, Two adjacent rows of sub-welding areas are offset from each other.

In the above technical solution, the welding zone includes multiple sub-welding zones, which are spaced apart on the tabs, effectively improving the stability of the multi-layer foil connection and the overall structural strength. In addition, the multi-point welding method can increase the polarity in a balanced manner. The thickness of the ear.

According to some embodiments of the present application, the pole tab includes a first surface and a second surface that are oppositely arranged along the thickness direction of the pole piece, the welding zone forms a concave portion on the first surface, and the welding zone forms a convex portion on the second surface.

In the above technical solution, the welding area forms a convex part on one side in the thickness direction of the pole tab, and a concave part is formed on the other side in the thickness direction of the pole tab. When the pole pieces are wound or stacked to form a multi-layer structure, the welding area is formed on The concave portion and the convex portion formed on the pole tabs can at least partially fit into each other, thereby further effectively blocking the vertical penetration of laser light into the main body of the pole piece through the gap between the pole tabs of the two layers of pole pieces.

According to some embodiments of the present application, the pole tab includes a first surface and a second surface arranged oppositely along the thickness direction of the pole piece. The area of the welding zone is S1 and the area of the first surface is S2, satisfying: 0.4≤S1/S2 ≤0.8.

In the above technical solution, the area of the welding zone occupies 40% to 80% of the area of the first surface of the tab, which can effectively ensure the overall structural strength and stability of the tab without increasing the process difficulty. If the area of the welding zone occupies a very large area, If the area of the first surface of the lug is too large, it will greatly increase the difficulty of the welding process, which is not conducive to improving production efficiency and introducing mass production; if the area of the welding area occupying the first surface of the lug is too small, the polarity cannot be guaranteed. The uniformity of the thickness of the lug cannot be effectively guaranteed, and the overall structural strength of the lug cannot be effectively guaranteed, thereby failing to effectively reduce the risk of deformation of the lug.

According to some embodiments of the present application, the plurality of foil materials include a first foil material and at least one second foil material. The first foil material is integrally formed with the base material, and the at least one second foil material is connected to the thickness direction of the first foil material. on one or both sides.

In the above technical solution, the plurality of foils include a first foil that is integrally formed with the base material. In actual production, a blank area uncoated with active material can be reserved on the base material, and this blank area forms the first foil. , and then connect the second foil material to the first foil material or the base material. The setting of the first foil material can provide a connection support point for the second foil material, thereby effectively reducing the process difficulty of connecting the tab to the base material. It is conducive to further improving battery production efficiency.

According to some embodiments of the present application, the first foil extends from one end to the other end in the length direction of the substrate.

In the above technical solution, the length of the first foil is consistent with the length of the base material, so that the pole piece can be rolled to form a full-tab electrode assembly, thereby further increasing the effective welding area of the pole and ensuring that the pole and current-carrying components The stability of the connection and effectively ensuring the overflow area of the tabs are conducive to ensuring the safety of the battery.

According to some embodiments of the present application, the second foil extends from one end to the other end in the length direction of the substrate.

In the above technical solution, the length of the second foil material is consistent with the length of the base material, so that the pole piece can be rolled to form a full-tab electrode assembly, and the uniformity of the thickness of the tab can be effectively ensured.

According to some embodiments of the present application, the second foil is connected to both sides in the thickness direction of the first foil.

In the above technical solution, the second foil material thickens the thickness of the first foil material from both sides in the thickness direction of the first foil material. Compared with the structure in which the second foil material is arranged on one side of the first foil material, the thickness of the first foil material can be effectively reduced. The risk of bending and deformation of the first foil material due to force.

According to some embodiments of the present application, the second foil materials are distributed in equal numbers on both sides of the first foil material in the thickness direction.

In the above technical solution, the second foil materials are distributed in equal numbers on both sides of the first foil material in the thickness direction, which further effectively reduces the risk of the first foil material being bent due to force.

According to some embodiments of the present application, the first foil material and the second foil material are made of the same material.

In the above technical solution, the first foil material and the second foil material are made of the same material to ensure stable polarity of the tabs.

According to some embodiments of the present application, the dimension of the second foil along the width direction of the pole piece is H1, and the dimension of the first foil along the width direction of the pole piece is H2, which satisfies; 1 mm ≤ H1 ≤ H2.

In the above technical solution, the width of the second foil material is greater than or equal to 1mm and less than or equal to the width of the first foil material to ensure that the second foil material evenly increases the thickness in the tab width direction and is effectively compatible with the incoming foil material error to ensure Welding area and welding operability between foils; at the same time, avoid the second foil being too wide and affecting the battery energy density. When the width of the second foil is too small, the effective welding width cannot be guaranteed, and the tab manufacturing process is difficult; when the second foil is too wide, it is not conducive to reducing material costs and battery cell weight, and will occupy too many battery cells. The internal space of the battery affects the energy density of the battery cell.

In a second aspect, the application provides an electrode assembly, including a positive electrode piece, a negative electrode piece and a separator. The positive electrode piece, the negative electrode piece and the separator are stacked and rolled to form an electrode assembly. The separator is disposed between the positive electrode piece and the negative electrode piece. time; wherein, at least one of the positive electrode piece and the negative electrode piece is the pole piece described in any one of the above.

In the above technical solution, the positive electrode piece, the negative electrode piece and the separator are stacked and rolled to form an electrode assembly. The tabs of the positive electrode piece and/or the negative electrode piece include multi-layer foil materials, and the tabs of the multi-layer foil materials effectively fill adjacent electrodes. The gap between the two layers of pole pieces effectively prevents the problem of welding through the main body of the electrode assembly during laser welding. At the same time, the multi-layer foil tab effectively increases the welding area of the welding end face of the tab, thereby effectively preventing laser welding. This can effectively improve the welding stability and effectively ensure the safety of the battery; in addition, it is not necessary to perform pre-processing such as flattening and stacking the tabs of the electrode assembly, thereby effectively simplifying the assembly process of the battery cells. , and avoid the waste of production time caused by the high failure rate of tab flattening, thereby effectively improving the production efficiency of the battery.

According to some embodiments of the present application, the electrode assembly is cylindrical.

In the above technical solution, the electrode assembly is cylindrical to form a cylindrical battery cell.

According to some embodiments of the present application, both the positive electrode piece and the negative electrode piece are the pole pieces described in any one of the above, the tab of the positive electrode piece is located at one end of the winding axis direction of the electrode assembly, and the tab of the negative electrode piece is The ear is located at the other end in the winding axis direction of the electrode assembly.

In the above technical solution, the tabs of the positive electrode piece and the negative electrode piece both include multi-layer foil materials, so that the tabs of the positive electrode piece and the tabs of the negative electrode piece are both thickened, thereby effectively ensuring the positive and negative electrodes of the electrode assembly. The stability of welding and the overall improvement of the production efficiency of the electrode assembly; the tabs of the positive electrode piece and the tabs of the negative electrode piece are distributed at both ends of the winding axis direction to facilitate the formation of a full-tab electrode assembly and ensure the tab end surface welding area.

According to some embodiments of the present application, the plurality of foils includes a first foil and at least one second foil, the first foil is integrally formed with the base material, and the at least one second foil is connected On one or both sides in the thickness direction of the first foil; the thickness of the positive electrode piece is D1, the thickness of the negative electrode piece is D2, the thickness of the first foil material is D3, so The thickness of the second foil is D4, the thickness of the separator is D5, and the number of layers of the second foil is n, which satisfies 0.3mm≤D4×n≤D1+D2+D5×2-D3.

In the above technical solution, if the overall thickness of the multi-layer second foil is too small, the structural stability and over-current capability of the tab cannot be effectively guaranteed, and the connection process with the base material is too difficult. If the thickness of the material is too thick, when the pole pieces are rolled or laminated, the tabs will be deformed due to overcrowding, which is not conducive to reducing the weight of the electrode assembly, and will cause the tabs to be too large, affecting the performance of the battery cells. Energy density, the overall thickness of the multi-layer second foil material in the technical solution of this application is greater than or equal to 0.3mm, effectively ensuring the structural stability and over-current capability of the tab, and ensuring the processing technology of connecting the second foil material to the base material Feasibility; at the same time, the overall thickness of the multi-layer second foil is less than or equal to the difference between the sum of the thicknesses of the first pole piece, the second pole piece and the two-layer separator and the thickness of the first foil, which can effectively avoid the winding of the pole piece Or after stacking, the tabs of two adjacent layers of pole pieces are too close together, causing excessive deformation of the tabs. At the same time, the overall volume of the tabs is prevented from being too large, which reduces the energy density of the battery cell and increases the overall weight of the battery cell.

In a second aspect, the present application provides a battery cell, including: an electrode assembly as described in any of the above solutions.

In a third aspect, the present application provides a battery, including the battery cell described in the above solution.

In a fourth aspect, the present application provides an electrical device, including the battery cell described in the above solution, where the battery cell is used to provide electric energy.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be 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 do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 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 by some embodiments of the present application;

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

Figure 4 is a front view of the deployed state of the pole piece provided by some embodiments of the present application;

Figure 5 is a partial cross-sectional view of the pole piece shown in Figure 4 along the A-A direction;

Figure 6 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application;

Figure 7 is a cross-sectional view of the electrode assembly shown in Figure 8 along the B-B direction;

FIG. 8 is a partial enlarged view of part C shown in FIG. 7 .

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

Marking description: 1000-vehicle; 100-battery; 10-box; 11-first part; 12-second part; 20-battery cell; 21-outer shell; 211-casing; 212-cover; 22-electrode Component; 221-positive electrode piece; 22a-main part; 2211-substrate; 2212-active material layer; 22b-pole tab; 2213-first foil material; 2214-second foil material; 2215-first surface; 2216 -Second surface; 2217-welding area; 2217a-sub-welding area; 2217b-concave part; 2217c-convex part; 222-negative electrode piece; 223-diaphragm; 23-adaptor; 200-controller; 300-motor.

X-first direction; Y-second direction; Z-third direction.

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 These are part of the embodiments of this application, but not all of them. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the application provided in the appended drawings is not intended to limit the scope of the claimed application, but rather to represent selected embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only used to illustrate the technical solution of the present application more clearly, and are therefore only used as examples and cannot be used to limit the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the technical field belonging to this application; the terms used herein are for the purpose of describing specific embodiments only and are not intended to be used in Limitation of this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

In the description of the embodiments of this application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying the relative importance or implicitly indicating the quantity or specificity of the indicated technical features. Sequence or priority relationship. In the description of the embodiments of this application, "plurality" means two or more, unless otherwise explicitly and specifically limited.

Reference herein 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 appearances 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. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of this application, the term "plurality" refers to two or more (including two).

In the description of the embodiments of this application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right" and "vertical" The orientation or positional relationships indicated by "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on those shown in the accompanying drawings. The orientation or positional relationship is only for the convenience of describing the embodiments of the present application and simplifying the description. It does 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 implementation of the present application. Example limitations.

In the description of the embodiments of the present application, unless otherwise explicitly stated and limited, technical terms such as "setting", "installation", "connecting", "connecting" and "fixing" should be understood in a broad sense. For example, it can be a fixed connection, or a fixed connection. It can be a detachable connection or integrated; it can be a mechanical connection, an electrical connection, or a signal connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an internal connection between two elements. interactive relationship. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of simplicity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length and width of the integrated device, are only illustrative illustrations and should not constitute any limitation to the present application. .

The battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. Among them, multiple battery cells can be connected in series, parallel or mixed. The battery may also include a case for enclosing one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

In this application, the battery cells may include lithium ion secondary batteries, lithium ion primary batteries, lithium-sulfur batteries, sodium lithium ion batteries, sodium ion batteries or magnesium ion batteries, etc., which are not limited in the embodiments of this application. The battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this.

The battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode plate, a negative electrode plate and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work. The positive electrode sheet includes a positive electrode current collector, a positive electrode active material layer and a positive electrode tab. 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 can protrude from the coated positive electrode active material layer. The positive electrode current collector in the material layer directly serves as the positive electrode tab. Of course, the positive electrode tab can also be set separately and then connected to the positive electrode current collector. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative electrode sheet includes a negative electrode current collector, a negative electrode active material layer and a negative electrode. 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 can protrude from the coated negative electrode active material layer. The negative electrode current collector directly serves as the negative electrode tab. Of course, the negative electrode tab can also be set separately and then connected to the negative electrode current collector. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon. In order to ensure that large currents can pass through without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolation film can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc. In addition, the electrode assembly may have a rolled structure or a laminated structure, and the embodiments of the present application are not limited thereto.

The battery cell may also include an electric energy extraction piece. The electric energy extraction piece plays a role of converging or overcurrent, and is usually welded to the tab of the electrode assembly to lead the electric energy of the electrode assembly out of the battery cell. The electric energy extraction part may include an adapter part, and the adapter part may be made of copper, aluminum, stainless steel, etc.

In battery production technology, how to improve battery production efficiency while ensuring battery safety is an urgent problem to be solved.

The inventor's research found that in order to avoid the problem of the laser passing through the gap between the multi-layer tabs and welding through the electrode assembly body, when welding the electrode assembly to the electrical energy extraction parts such as adapters, smoothing and smoothing are usually used. Pre-process the tabs by other means to increase the effective welding area of the tabs. The gaps between the multi-layer tabs can be effectively filled by kneading and leveling, thereby blocking the welding laser from vertically entering the electrode through the gaps between the tabs. components to effectively ensure the safety performance of the electrode components, thereby ensuring the safety of the battery.

Then, the inventor noticed that when the tabs were pre-processed by methods such as kneading and smoothing, the failure rate and defective rate remained high, seriously affecting the overall production efficiency of the battery.

In order to effectively improve the assembly efficiency of the battery while ensuring the safety of the battery, the inventor designed a pole piece after research. The pole tab of the pole piece includes a plurality of foil materials stacked along the thickness direction of the pole piece. The overall pole piece The thickness of the ears is greater than the thickness of the base material.

The arrangement of multi-layer foil effectively increases the thickness of the tabs. After the pole pieces form the electrode assembly, the tabs of the multi-layer foil effectively fill the gap between the two adjacent layers of pole pieces, thereby effectively preventing the electrode assembly from being welded through during laser welding. The problem of the main body, and the multi-layer foil tabs effectively increase the welding area of the welding end face of the tabs, thereby preventing the problem of false welding. Therefore, the structure of the tabs of the present application is conducive to ensuring the safety of the battery; at the same time, because of the multiple The tabs made of a layer of foil material effectively increase the welding area of the welding end face of the tabs, so when welding the tabs to adapters or other power overcurrent and busing components, there is no need to perform pre-processing such as flattening or stacking the tabs. , thereby effectively simplifying the assembly process of battery cells, and avoiding the waste of production time caused by the high failure rate of tab flattening, thereby effectively improving the production efficiency of the battery.

The battery cells disclosed in the embodiments of the present application can be used in, but are not limited to, electrical devices such as vehicles, ships, or aircrafts. A power supply system including the battery cells, batteries, etc. disclosed in this application can be used to form the electrical device.

Embodiments of the present application provide an electrical device that uses a battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.

The battery described in the embodiments of the present application is not limited to the above-described electrical devices, but can also be applied to all electrical devices that use batteries. However, for the sake of simplicity of description, the following embodiment is based on an embodiment of the present application. The electric device is a vehicle as an example for explanation.

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 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. The battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed at the bottom, head, or tail of the vehicle 1000 . The battery 100 may be used to power the vehicle 1000 , for example, the battery 100 may serve as an operating power source for the vehicle 1000 . The vehicle 1000 may also include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .

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

Please refer to FIG. 2 , which is an exploded view of the battery 100 provided by some embodiments of the present application. The battery 100 may include a box 10 and a battery cell 20 , and the battery cell 20 is accommodated in the box 10 . Among them, the box 10 is used to provide an accommodation space for the battery cells 20, and the box 10 can adopt a variety of structures. In some embodiments, the box 10 may include a first part 11 and a second part 12 , the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a space for accommodating the battery cells 20 of accommodation space. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure. The first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define a receiving space. ; The first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 is covered with the open side of the second part 12. Of course, the box 10 formed by the first part 11 and the second part 12 can be in various shapes, such as rectangular parallelepiped, cube, etc.

In the battery 100, there may be a plurality of battery cells 20, and the plurality of battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the plurality of battery cells 20 are connected in series and in parallel. Multiple battery cells 20 can be directly connected in series or in parallel or mixed together.

Please refer to Figure 3. Figure 3 is an exploded view of the battery cell 20 provided by some embodiments of the present application. The battery cell 20 provided by some embodiments of the present application may include a housing 21, an electrode assembly 22 and an electric energy extraction member. The housing 21 is Component for housing electrode assembly 22. The housing 21 can be in various shapes, such as cylinder, cuboid, etc. The housing 21 may include a housing 211 and a cover 212. The cover 212 covers the opening of the housing 211. The cover 212 and the housing 211 jointly define a space for accommodating the electrode assembly 22, the electric energy extraction member, the electrolyte and other components. sealed space. Sealed space.

The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. Electrode assembly 22 may include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 22 may be a rolled structure formed by winding the positive electrode piece, the separator and the negative electrode piece, or may be a laminate structure.

The electric energy extraction part is arranged in the housing 21 and connected with the electrode assembly 22 . The electrical energy outlet plays the role of overcurrent and convergence. The electric energy extraction component may be an adapter 23, and the adapter 23 and the tabs 22b of the electrode assembly 22 may be welded. The material of the adapter can be copper, aluminum or stainless steel.

Please refer to Figure 3, and further refer to Figures 4 and 5. Figure 4 is a front view of the unfolded state of the pole piece provided by some embodiments of the present application; Figure 5 is a partial cross-sectional view of the pole piece shown in Figure 4 in the A-A direction. Some embodiments of the present application provide a pole piece. The pole piece includes a main body part 22a and a pole tab 22b. The main body part 22a includes a base material 2211. The pole tab 22b is connected to the base material 2211. The pole tab 22b includes a thickness along the pole piece. A plurality of foil materials are stacked in different directions, and the thickness of the tab 22b is greater than the thickness of the base material 2211.

It can be understood that the main body part 22a may include a base material 2211 and an active material layer 2212 coated on the base material 2211.

The base material 2211 is the aforementioned current collector. The electrode piece can be a positive electrode piece or a negative electrode piece. When the electrode piece is a positive electrode piece, the base material 2211 can be a positive electrode current collector. When the electrode piece is a negative electrode piece, , the base material 2211 may be a negative electrode current collector. For convenience of explanation, the following example uses the positive electrode piece 221 as the electrode piece.

The pole tab 22b includes a plurality of foil materials stacked along the thickness direction of the pole piece. As shown in Figure 5, the thickness direction of the pole piece extends along the first direction X, and the multiple foil materials of the pole tab 22b are stacked along the first direction X. set up.

The plurality of foil materials can be arranged separately and fixedly connected to the base material 2211 one by one through welding or other methods. The plurality of foil materials can also be connected to each other to form an integral structure and connected to the base material 2211. For example, multiple foil materials can be welded to each other to form an integrally connected structure.

Among them, foil refers to an extremely thin metal sheet with conductive properties. The material of foil can be copper, aluminum or stainless steel. The materials of the foil material and the base material 2211 may be the same or different.

In the technical solution of this application, the pole tab 22b of the pole piece includes a plurality of foil materials stacked along the thickness direction of the pole piece. The overall thickness of the pole tab 22b formed by the multi-layer foil materials is greater than the thickness of the base material 2211. The pole piece is rolled After the electrode assembly 22 is formed, the tabs 22b of the multi-layer foil material effectively fill the gap between the two adjacent layers of pole pieces, thereby effectively preventing the problem of welding through the main body part 22a during laser welding. At the same time, the pole tabs 22b of the multi-layer foil material The lug 22b effectively increases the welding area of the welding end surface of the lug 22b, thereby preventing the problem of false welding. Therefore, the structure of the lug 22b of the present application is conducive to ensuring the safety of the battery 100; at the same time, because the multi-layer foil lug 22b is effective The welding area of the welding end face of the pole lug 22b is increased, so when welding the pole lug 22b to the adapter or other electric energy overcurrent and converging components, it is not necessary to perform pre-processing such as flattening or stacking the pole lug 22b, thus effectively simplifying The assembly process of the battery cells 20 avoids the waste of production time caused by the high failure rate of flattening the tabs 22b, thereby effectively improving the production efficiency of the battery 100.

According to some embodiments of the present application, the thickness of the tab 22b is greater than the thickness of the main body portion 22a.

As mentioned above, the main body part 22a includes a base material 2211 and an active material layer 2212 coated on the base material 2211. The thickness of the tab 22b is greater than the thickness of the main body part 22a, which means that the overall thickness of the multi-layer foil is greater than that of the base material. 2211 and the active material layer 2212 including the thickness of the entire main body portion 22a.

Specifically, as shown in FIG. 5 , the thickness direction of the pole tabs 22 b extends along the thickness direction of the plurality of foil materials (ie, the first direction X shown in the figure), and the thickness direction of the main body portion 22 a extends along the thickness direction of the pole piece. (ie, the first direction X shown in the figure) extends.

If the thickness of the pole tab 22b is greater than the thickness of the main body area of the pole piece, then after the pole pieces are rolled or stacked into a multi-layer structure to form the electrode assembly 22, it can effectively ensure that the pole tab 22b can more fully fill the gap between two adjacent layers of pole pieces. The gap reduces the risk of the laser penetrating into the main body 22a through the gap between the pole tabs 22b of the two layers of pole pieces, thereby effectively ensuring the safety of the battery 100.

According to some embodiments of the present application, please continue to refer to Figures 4 and 5, multiple foils are welded to each other to form a welding area 2217.

Welding multiple foil materials to each other means welding multiple foil materials to each other along their stacking direction (ie, the first direction X).

The welding area 2217 refers to an area where multiple foils are connected to each other along their stacking direction.

Among them, multiple foils can be welded by laser welding or other welding methods, or multiple foils can be welded to each other by ultrasonic seam welding.

Multiple foils are welded to each other to form a welding area 2217. The welding area 2217 formed by welding can further thicken the thickness of the tab 22b. In this way, the thickness requirement of the tab 22b can be achieved by using a smaller number of foil layers to weld each other. It is beneficial to save foil and reduce the weight of the tab 22b; at the same time, multiple foils are welded to each other, which can effectively improve the overall structural strength and stability of the tab 22b, thereby reducing the bending of the tab 22b during the winding and stacking process of the pole piece. Risk of deformation such as bending and warping.

According to some embodiments of the present application, the welding area 2217 includes multiple rows of sub-welding areas 2217a. The multiple rows of sub-welding areas 2217a are arranged along the width direction of the pole piece. Each row of sub-welding areas 2217a includes multiple rows of sub-welding areas 2217a spaced along the length direction of the pole piece. Sub-welding areas 2217a, two adjacent rows of sub-welding areas 2217a are offset from each other.

Specifically, as shown in FIG. 4 , the width direction of the positive electrode piece 221 extends along the third direction Z, the length direction of the positive electrode piece 221 extends along the second direction Y, and the multiple rows of sub-welding areas 2217a are arranged along the third direction Z. , each row of sub-welding areas 2217a includes a plurality of sub-welding areas 2217a spaced apart along the second direction Y.

In some other embodiments, multiple rows of sub-welding areas 2217a may also be arranged along the second direction Y, and each row of sub-welding areas 2217a includes a plurality of sub-welding areas 2217a spaced apart along the third direction Z.

The welding area 2217 includes a plurality of sub-welding areas 2217a, that is, multi-point welding of multiple foils, which effectively improves the stability of the multi-layer foil connection and the overall structural strength. In addition, the multi-point welding method can increase the thickness of the tab 22b in a balanced manner.

According to some embodiments of the present application, as shown in Figure 5, the pole tab 22b includes a first surface 2215 and a second surface 2216 that are oppositely arranged along the thickness direction of the pole piece. The welding area 2217 forms a recess 2217b on the first surface 2215. Region 2217 forms a convex portion 2217c on second surface 2216.

The thickness direction of the pole piece extends along the first direction X, that is to say, the pole tab 22b includes a first surface 2215 and a second surface 2216 that are oppositely arranged along the first direction A convex portion 2217c is formed on the second surface 2216 at a position corresponding to the concave portion 2217b.

For example, the multi-layer foil material can be welded by seam welding. During the seam welding process, the welding head forms a concave portion 2217b on the first surface 2215 and a convex portion 2217c on the second surface 2216.

The welding area 2217 forms a convex portion 2217c on one side of the pole tab 22b in the thickness direction, and a concave portion 2217b on the other side of the pole tab 22b in the thickness direction. When the pole pieces are rolled or stacked to form a multi-layer structure, the welding area 2217 The concave portion 2217b and the convex portion 2217c formed on the pole tab 22b can at least partially fit into each other, thereby further effectively blocking the vertical penetration of laser light into the main body portion 22a of the pole piece through the gap between the pole tabs 22b of the two layers of pole pieces.

According to some embodiments of the present application, the pole tab 22b includes a first surface 2215 and a second surface 2216 that are oppositely arranged along the thickness direction of the pole piece. The area of the welding zone 2217 is S1, and the area of the first surface 2215 is S2, which satisfies: 0.4≤S1/S2≤0.8.

As mentioned above, the tab 22b includes a first surface 2215 and a second surface 2216 that are oppositely arranged along the first direction X, and the area of the welding area 2217 in the plane perpendicular to the first direction X is S1.

0.4≤S1/S2≤0.8, that is, the ratio of the area S1 of the welding zone 2217 to the area S2 of the first surface 2215 can be 0.4/0.43, 0.5, 0.6, 0.7, 0.75, 0.8, etc., which is greater than or equal to 0.4 and less than or equal to 0.8. Value, in some embodiments, may satisfy 0.4≤S1/S2≤0.6. Optionally, the ratio of the area S1 of the welding area 2217 to the area S2 of the first surface 2215 is 0.6.

If the area of the welding zone 2217 occupies an excessively large area of the first surface 2215 of the pole lug 22b, the difficulty of the welding process will be greatly increased, which is not conducive to improving production efficiency and introducing mass production; if the area of the welding zone 2217 occupies the first surface 2215 of the pole lug 22b, If the area of surface 2215 is too small, the uniformity of the thickness of tab 22b cannot be guaranteed, and the overall structural strength of tab 22b cannot be effectively guaranteed, thereby failing to effectively reduce the risk of deformation of tab 22b. The area of welding zone 2217 occupies a very large area. The area of the first surface 2215 of the lug 22b is 40% to 80%, which can effectively ensure the overall structural strength and stability of the lug 22b without increasing the process difficulty.

According to some embodiments of the present application, please continue to refer to Figure 5. The plurality of foils includes a first foil 2213 and at least one second foil 2214. The first foil 2213 is integrally formed with the base material 2211, and the at least one second foil The material 2214 is connected to one or both sides of the first foil material 2213 in the thickness direction.

The second foil material can be connected to both sides or one side of the first foil material 2213 in the thickness direction through a welding process. The number of the second foil material 2214 can be one or multiple. When the second foil material 2214 When there are multiple second foils 2214 , all of them may be located on one side of the first foil 2213 in the thickness direction, or they may be distributed on both sides of the first foil 2213 in the thickness direction.

In an actual process, the area of the substrate 2211 that is not coated with the active material layer 2212 can directly form the first foil 2213.

The plurality of foil materials include a first foil material 2213 that is integrally formed with the base material 2211. In actual production, a blank area uncoated with active material can be reserved on the base material 2211, and the blank area forms the first foil material 2213. Then the second foil material 2214 is connected to the first foil material 2213 or the base material 2211. The arrangement of the first foil material 2213 can provide a connection support point for the second foil material 2214, thereby effectively reducing the connection between the tab 22b and the base material. The process difficulty of 2211 is conducive to further improving the production efficiency of battery 100.

According to some embodiments of the present application, the first foil 2213 extends from one end to the other end in the length direction of the substrate 2211.

The length direction of the base material 2211 extends along the second direction Y, and the first foil material 2213 extends from one end of the base material 2211 in the second direction Y to the other end of the base material 2211 in the second direction Y.

The length of the first foil material is consistent with the length of the base material 2211, so that the electrode assembly 22 with full tab 22b can be formed after the pole piece is rolled, thereby further increasing the effective welding area of the tab 22b and ensuring that the tab 22b is connected to the current-carrying components. The stability of the connection and the effective flow area of the tab 22b are ensured, which is conducive to ensuring the safety of the battery 100.

According to some embodiments of the present application, the second foil 2214 extends from one end to the other end in the length direction of the substrate 2211.

The length direction of the base material 2211 extends along the second direction Y, and the second foil material 2214 extends from one end of the base material 2211 in the second direction Y to the other end of the base material 2211 in the second direction Y.

The length of the second foil material is consistent with the length of the base material 2211, so that the pole piece can be rolled to form the electrode assembly 22 with all tabs 22b, and the uniformity of the thickness of the tabs 22b can be effectively ensured.

According to some embodiments of the present application, as shown in FIG. 5 , the second foil 2214 is connected to both sides of the first foil 2213 in the thickness direction.

Specifically, the second foil materials 2214 include a plurality of second foil materials 2214, and the plurality of second foil materials 2214 are distributed on both sides of the thickness direction of the first foil material 2213. One second foil 2214 may be provided on the same side of the first foil 2213 in the thickness direction, or two, three, four or even more second foils 2214 may be stacked.

The number of the second foil 2214 on both sides of the first foil 2213 in the thickness direction may be the same or different.

The second foil material thickens the thickness of the first foil material 2213 from both sides in the thickness direction of the first foil material 2213. Compared with the structure in which the second foil material 2214 is provided on one side of the first foil material 2213, the second foil material 2213 can effectively reduce the thickness of the first foil material 2213. There is a risk of bending and deformation of the foil material 2213 due to force.

According to some embodiments of the present application, the second foil 2214 is distributed in equal numbers on both sides of the first foil 2213 in the thickness direction.

The number of the second foil materials in the thickness direction of the first foil material 2213 may be one, two, three or even more.

The second foil materials are distributed in equal numbers on both sides of the first foil material 2213 in the thickness direction, further effectively reducing the risk of the first foil material 2213 being bent due to force.

According to some embodiments of the present application, the first foil material 2213 and the second foil material 2214 are made of the same material.

The first foil material 2213 and the base material 2211 are integrally formed. The first foil material 2213 can be made of the same material as the base material 2211. At the same time, the second foil material 2214 can also be made of the same material as the base material 2211.

The first foil material and the second foil material 2214 are made of the same material to ensure the stability of the polarity of the tab 22b and at the same time, facilitate the processing and manufacturing of the tab 22b.

According to some embodiments of the present application, the dimension of the second foil 2214 along the width direction of the pole piece is H1, and the dimension of the first foil 2213 along the width direction of the pole piece is H2, which satisfies; 1 mm ≤ H1 ≤ H2.

As shown in FIG. 5 , the width direction of the pole piece extends along the third direction Z, the dimension of the second foil 2214 along the third direction Z is H1, and the dimension of the first foil 2213 along the third direction Z is H2.

The size of the second foil 2214 along the third direction Z and the size of the first foil 2213 along the third direction Z are both greater than or equal to 1 mm. At the same time, the size of the second foil 2214 along the third direction Z is less than or equal to The size of the first foil 2213 along the third direction Z.

Specifically, the size of the second foil 2214 along the third direction Z may be 1 mm, or 1.1 mm, 1.2 mm, 2 mm, 3 mm, etc., and the size of the first foil 2213 along the third direction Z may be the same as The size of the second foil 2214 along the third direction Z is the same, or may be larger than the size of the second foil 2214 along the third direction Z. For example, the size of the second foil 2214 along the third direction Z is the same as the size of the first foil 2213 along the third direction Z.

The width of the second foil material is greater than or equal to 1 mm and less than or equal to the width of the first foil material 2213 to ensure that the second foil material 2214 evenly increases the thickness of the tab 22b in the width direction and is effectively compatible with the incoming foil material error to ensure that the foil material the welding area and welding operability; at the same time, the second foil 2214 is prevented from being too wide and affecting the energy density of the battery 100. When the width of the second foil 2214 is too small, the effective welding width cannot be guaranteed, and the manufacturing process of the tab 22b is difficult; when the second foil 2214 is too wide, it is not conducive to reducing the material cost and the weight of the battery cell 20, and will occupy Too much internal space of the battery cell 20 affects the energy density of the battery cell 20 .

Please continue to refer to Figures 3 to 5, and further refer to Figures 6 to 8. Figure 6 is a schematic structural diagram of an electrode assembly provided by some embodiments of the present application; Figure 7 is a cross-sectional view of the electrode assembly shown in Figure 8 along the B-B direction. ; Figure 8 is a partial enlarged view of part C shown in Figure 7. Some embodiments of the present application provide an electrode assembly 22. The electrode assembly 22 includes a positive electrode piece 221, a negative electrode piece 222 and a separator 223. The positive electrode piece 221, the negative electrode piece 222 and the separator 223 are stacked and rolled to form the electrode assembly 22. The separator 223 is disposed between the positive electrode piece 221 and the negative electrode piece 222; wherein at least one of the positive electrode piece 221 and the negative electrode piece 222 is the electrode piece described in any of the above solutions.

For example, both the positive electrode piece 221 and the negative electrode piece 222 are the electrode pieces of the above solution.

The positive electrode piece 221, the negative electrode piece 222 and the separator 223 are stacked and rolled to form the electrode assembly 22. The tabs 22b of the positive electrode piece 221 and/or the negative electrode piece 222 include multi-layer foil materials, and the tabs 22b of the multi-layer foil materials are effective. The gap between two adjacent layers of pole pieces is filled, thereby effectively preventing the problem of welding through the main body 22a of the electrode assembly 22 during laser welding. At the same time, the multi-layer foil pole tab 22b effectively increases the welding capacity of the welding end surface of the pole tab 22b. area, thereby effectively preventing the problem of false welding during laser welding, thereby effectively improving the welding stability, and effectively ensuring the safety of the battery 100; furthermore, there is no need to perform pre-processing such as flattening and stacking the tabs 22b of the electrode assembly 22 , thereby effectively simplifying the assembly process of the battery cells 20 and avoiding the waste of production time caused by the high failure rate of flattening the tabs 22b, thereby effectively improving the production efficiency of the battery 100.

According to some embodiments of the present application, the electrode assembly 22 is cylindrical so as to form a cylindrical battery cell 20 .

Of course, in other embodiments, the electrode assembly 22 may also have a flat structure.

According to some embodiments of the present application, both the positive electrode piece 221 and the negative electrode piece 222 are the electrode pieces described in any of the above solutions, and the tab 22b of the positive electrode piece 221 is located at one end in the direction of the winding axis of the electrode assembly 22, The tab 22 b of the negative electrode piece 222 is located at the other end in the winding axis direction of the electrode assembly 22 .

As shown in FIG. 6 , the winding axis of the electrode assembly 22 extends along the third direction Z, the tab 22b of the positive electrode piece 221 is located at one end of the electrode assembly 22 along the third direction Z, and the tab 22b of the negative electrode piece 222 is located at The other end of the electrode assembly 22 along the third direction Z.

The tabs 22b of the positive electrode piece 221 and the negative electrode piece 222 both include multi-layer foil materials, so that the tabs 22b of the positive electrode piece 221 and the tabs 22b of the negative electrode piece 222 are both thickened, thereby effectively ensuring the durability of the electrode assembly 22 The stability of the positive and negative electrode welding is improved, and the overall production efficiency of the electrode assembly 22 is improved; the tabs 22b of the positive electrode piece 221 and the tabs 22b of the negative electrode piece 222 are distributed at both ends of the winding axis direction to facilitate the formation of a full pole The lug 22b electrode assembly 22 ensures the welding area of the end surface of the lug 22b.

According to some embodiments of the present application, as shown in FIGS. 7 and 8 , the plurality of foils includes a first foil 2213 and at least one second foil 2214 , and the first foil 2213 is in contact with the base material. 2211 is integrally formed, and the at least one second foil 2214 is connected to one or both sides of the first foil 2213 in the thickness direction; the thickness of the positive electrode piece 221 is D1, and the negative electrode piece 222 The thickness of is D2, the thickness of the first foil 2213 is D3, the thickness of the second foil 2214 is D4, the thickness of the separator 223 is D5, and the number of layers of the second foil 2214 is n , satisfying, 0.3mm≤D4×n≤D1+D2+D5×2-D3.

The thickness D4 of the second foil material is multiplied by the number of layers n of the second foil material 2214 to obtain the overall thickness dimension of the second foil material 2214. The overall thickness of the second foil material 2214 can be 0.3mm, 0.4mm, 0.5mm, etc. Any value greater than or equal to 0.3mm.

For example, D1=5mm, D2=5mm, D3=1mm, D4=0.5mm, D5=1mm, n=20, D1+D2+D5×2-D3=11mm, D4×n=10mm, D4×n <D1+D2+D5×2-D3.

The tabs 22b of pole pieces with the same polarity are located at the same end in the direction of the winding axis of the electrode assembly 22. Two adjacent layers of pole pieces with the same polarity are separated by a layer of pole pieces and two layers of opposite polarity. Diaphragm 223, when D4×n=D1+D2+D5×2-D3, the tabs 22b of two adjacent layers of pole pieces with the same polarity can cover the gap between the two layers of pole pieces as much as possible. When D4×n is greater than D1+D2+D5×2-D3, as the overall thickness of the second foil 2214 increases, the tabs 22b will expand outward along the radial direction of the winding axis of the electrode assembly 22, occupying the battery cell. There will be too much space in the body 20 and the weight of the tabs 22b will be increased. In addition, the tabs 22b of the two layers of pole pieces with the same polarity will fit too closely, which will affect the smoothness of the electrolyte infiltration. Therefore, the overall thickness of the second foil 2214 may be equal to or less than D1 + D2 + D5 × 2 - D3.

If the overall thickness of the multi-layer second foil material 2214 is too small, the structural stability and over-current capability of the tab 22b cannot be effectively guaranteed, and the connection process with the base material 2211 is too difficult. If the multi-layer second foil material 2214 If the thickness of the electrode assembly is too thick, when the pole pieces are wound or stacked, the tabs 22b will be deformed due to overcrowding, which is not conducive to reducing the weight of the electrode assembly 22, and will cause the tabs 22b to be too large, affecting the battery cells. At the same time, the smoothness of electrolyte infiltration will also be affected because the tabs 22b of the two layers of pole pieces with the same polarity are too closely attached. The overall thickness of the multi-layer second foil material 2214 in the technical solution of this application is greater than or equal to 0.3mm, which effectively ensures the structural stability and flow capacity of the tab 22b and ensures the processing technology for connecting the second foil material 2214 to the base material 2211 The feasibility of After the pole pieces are wound or laminated, the tabs 22b of two adjacent layers of pole pieces with the same polarity are too closely attached, which affects the energy density of the battery cell 20 and the smooth infiltration of the electrolyte.

According to some embodiments of the present application, the present application also provides a battery cell 20. The battery cell 20 includes the electrode assembly 22 as described in any of the above solutions.

According to some embodiments of the present application, the present application provides a battery 100 including the battery cell 20 described in the above solution.

According to some embodiments of the present application, the present application also provides an electrical device, including the battery cell 20 described in the above solution, and the battery cell 20 is used to provide electric energy.

The electrical device may be any of the aforementioned electrical devices.

Please refer to Figures 3 to 8. Some embodiments of the present application provide a pole piece. The pole piece includes a main body part 22a and a pole lug 22b. The main body part 22a includes a base material 2211. The pole lug 22b is connected to the base material 2211. The ear 22b includes a plurality of foil materials stacked along the thickness direction of the pole piece.

The plurality of foil materials include a first foil material 2213 and a plurality of second foil materials 2214. The first foil material 2213 is integrally formed with the base material 2211, and the plurality of second foil materials 2214 are connected to the first foil material 2213 in the thickness direction. On both sides, the number of the second foil 2214 on both sides in the thickness direction of the first foil 2213 is the same. Both the first foil material 2213 and the second foil material 2214 extend from one end to the other end in the length direction of the base material 2211 .

Among them, the plurality of second foils 2214 and the first foil 2213 mutually form a welding area 2217, and the welding area 2217 includes multiple rows of sub-welding areas 2217a. The multiple rows of sub-welding areas 2217a are arranged along the width direction of the pole piece, and each row The sub-welding areas 2217a include a plurality of sub-welding areas 2217a spaced apart along the length direction of the pole piece, and two adjacent rows of sub-welding areas 2217a are offset from each other.

The pole tab 22b includes a first surface 2215 and a second surface 2216 that are oppositely arranged along the thickness direction of the pole piece. A plurality of sub-welding areas 2217a form a plurality of recesses 2217b on the first surface 2215, and a plurality of sub-welding areas 2217a are formed on the second surface 2216. A plurality of convex portions 2217c.

It should be noted that, as long as there is no conflict, the features of the embodiments in this application can be combined with each other.

While the present application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for parts 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 way. The application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims (20)

1. A pole piece including:

   The main body part includes a base material;

   The pole tab is connected to the base material. The pole tab includes a plurality of foil materials stacked along the thickness direction of the pole piece. The thickness of the pole tab is greater than the thickness of the base material.
2. The pole piece according to claim 1, wherein the thickness of the pole tab is greater than the thickness of the main body part.
3. The pole piece according to claim 1 or 2, wherein the plurality of foil materials are welded to each other to form a welding zone.
4. The pole piece according to claim 3, wherein the welding area includes multiple rows of sub-welding areas, the multiple rows of sub-welding areas are arranged along the width direction of the pole piece, and each row of sub-welding areas includes a A plurality of sub-welding areas are arranged at intervals in the length direction of the piece, and two adjacent rows of sub-welding areas are arranged offset from each other.
5. The pole piece according to claim 3 or 4, wherein the pole tab includes a first surface and a second surface oppositely arranged along the thickness direction of the pole piece, and the welding area forms a recess on the first surface. , the welding area forms a convex portion on the second surface.
6. The pole piece according to claim 5, wherein the pole tab includes a first surface and a second surface arranged oppositely along the thickness direction of the pole piece, the area of the welding zone is S1, and the first surface The area is S2, satisfying: 0.4≤S1/S2≤0.8.
7. The pole piece according to any one of claims 1 to 6, wherein the plurality of foils includes a first foil and at least one second foil, the first foil being integrally formed with the base material , the at least one second foil is connected to one or both sides in the thickness direction of the first foil.
8. The pole piece according to claim 7, wherein the first foil extends from one end to the other end in the length direction of the base material.
9. The pole piece according to claim 7 or 8, wherein the second foil extends from one end to the other end in the length direction of the base material.
10. The pole piece according to any one of claims 7 to 9, wherein the second foil is connected to both sides of the first foil in the thickness direction.
11. The pole piece according to claim 10, wherein the second foil materials are distributed in equal numbers on both sides of the first foil material in the thickness direction.
12. The pole piece according to any one of claims 7-11, wherein the first foil material and the second foil material are made of the same material.
13. The pole piece according to any one of claims 7-12, wherein the dimension of the second foil material along the width direction of the pole piece is H1, and the dimension of the first foil material along the width direction of the pole piece is H1. The dimension in the width direction is H2, which satisfies; 1mm≤H1≤H2.
14. An electrode assembly, including a positive electrode piece, a negative electrode piece and a separator. The positive electrode piece, the negative electrode piece and the separator are stacked and rolled to form the electrode assembly. The separator is disposed on the positive electrode piece. and between the negative electrode piece;

    Wherein, at least one of the positive electrode piece and the negative electrode piece is the electrode piece according to any one of claims 1-13.
15. The electrode assembly of claim 14, wherein the electrode assembly is cylindrical.
16. The electrode assembly according to claim 14 or 15, wherein the positive electrode piece and the negative electrode piece are the electrode pieces according to any one of claims 1 to 13, and the tabs of the positive electrode piece Located at one end in the direction of the winding axis of the electrode assembly, the tab of the negative electrode piece is located at the other end in the direction of the winding axis of the electrode assembly.
17. The electrode assembly according to claim 16, wherein the plurality of foils includes a first foil and at least one second foil, the first foil is integrally formed with the base material, and the at least one second foil The two foils are connected to one or both sides in the thickness direction of the first foil;

    The thickness of the positive electrode piece is D1, the thickness of the negative electrode piece is D2, the thickness of the first foil material is D3, the thickness of the second foil material is D4, and the thickness of the separator is D5, The number of layers of the second foil material is n, which satisfies 0.3mm≤D4×n≤D1+D2+D5×2-D3.
18. A battery cell including:

    The electrode assembly according to any one of claims 14-17.
19. A battery comprising the battery cell according to claim 18.
20. An electrical device, comprising the battery cell as claimed in claim 18, the battery cell being used to provide electrical energy.

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