CN117859232A

CN117859232A - Electrode assembly, battery cell, battery and electricity utilization device

Info

Publication number: CN117859232A
Application number: CN202280005695.5A
Authority: CN
Inventors: 陈江; 周建华; 宋晋阳; 吴凯
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-08-08
Filing date: 2022-08-08
Publication date: 2024-04-09
Also published as: WO2024031254A1

Abstract

The application provides an electrode assembly, a battery monomer, a battery and an electricity utilization device, and belongs to the technical field of batteries. The electrode assembly comprises a first pole piece and a second pole piece which are opposite in polarity, the first pole piece and the second pole piece are wound in the winding direction to form the electrode assembly, and the first pole piece is provided with a first winding tail end. One side of the first pole piece and/or one side of the second pole piece is provided with a first concave area, and along the radial direction of the electrode assembly, the projection of the first winding tail end is positioned in the first concave area. The expansion space can be provided for the first winding ending end of the first pole piece in the radial direction of the electrode assembly through the first concave area, so that the phenomenon that the first winding ending end extrudes the pole piece at the adjacent part of the electrode assembly can be relieved, the phenomenon that the shearing stress is concentrated at the first winding ending end is reduced, and then the risk that the first pole piece or the second pole piece of the electrode assembly deforms or cracks due to extrusion of the first winding ending end can be reduced, so that the use safety of the electrode assembly is improved.

Description

Electrode assembly, battery cell, battery and electricity utilization device

Technical Field

The application relates to the technical field of batteries, in particular to an electrode assembly, a battery cell, a battery and an electric device.

Background

In recent years, new energy automobiles have been developed dramatically, and in the field of electric automobiles, a power battery plays an important role as a power source of the electric automobile. Along with the great popularization of new energy automobiles, the demand for power battery products is also growing, and batteries as core parts of the new energy automobiles have higher requirements on the use safety.

The battery cell is obtained by assembling an electrode assembly (bare cell) by winding or laminating a positive electrode plate, a negative electrode plate and a separation film, then filling the electrode assembly into a shell, and then injecting electrolyte. The electrode assembly of the winding structure has the advantages of convenience in assembly, low manufacturing difficulty, high production efficiency and the like, and therefore, the electrode assembly of the winding structure is widely applied.

For the electrode assemblies with the winding structures in some related technologies, researchers find that after the electrode assemblies are charged and discharged, a pole piece in the electrode assemblies can generate a cracking phenomenon due to some unknown reasons, and the pole piece cracking can cause a series of problems such as increase of internal resistance of a battery cell, so that a great potential safety hazard exists in the use process of the battery cell. Therefore, it is necessary to specify the cause of the cracking of the electrode sheet and develop an improvement scheme to alleviate the cracking of the electrode sheet in the electrode assembly so as to improve the use safety of the battery cell.

Disclosure of Invention

The embodiment of the application provides an electrode assembly, a battery cell, a battery and an electricity utilization device, and can effectively improve the use safety of the battery cell.

In a first aspect, embodiments of the present application provide an electrode assembly, including a first pole piece and a second pole piece having opposite polarities, where the first pole piece and the second pole piece are wound in a winding direction to form the electrode assembly, and the first pole piece has a first winding tail end; and the projection of the tail end of the first winding is positioned in the first concave area along the radial direction of the electrode assembly.

According to the technical scheme, the first concave area which is arranged corresponding to the first winding tail end is arranged on one side of the first pole piece and/or the second pole piece, and the projection of the first winding tail end on the radial direction of the electrode assembly falls into the first concave area, so that when the first winding tail end of the first pole piece is expanded in the use process of the electrode assembly, the first concave area can provide enough expansion space for the first winding tail end of the first pole piece in the radial direction of the electrode assembly, so that the phenomenon that the first winding tail end presses the first pole piece or the second pole piece at the adjacent position of the electrode assembly is relieved, the shearing stress of the first winding tail end on the adjacent first pole piece or second pole piece can be released, the phenomenon that the shearing stress is concentrated at the first winding tail end is reduced, the risk that the first pole piece or the second pole piece of the electrode assembly is locally deformed or cracked due to the extrusion of the first winding tail end is reduced, and the use safety of a battery cell with the electrode assembly is improved.

In some embodiments, the first recessed region has a width D in the winding direction ₁ Satisfy D ₁ ≥10mm。

In the above technical scheme, the width of the first concave region in the winding direction is set to be not less than 10mm, and since the first winding tail end can play along the winding direction due to expansion of the electrode assembly in the use process and play is within 10mm, the electrode assembly adopting the structure can ensure that the projection of the first winding tail end in the radial direction of the electrode assembly is positioned in the first concave region when the first winding tail end plays along the winding direction, so that the first concave region can stably provide expansion space for the first winding tail end.

In some embodiments, the outermost ring of the electrode assembly is the first pole piece, the second pole piece has a second winding tail end, and the first winding tail end extends beyond the second winding tail end along the winding direction; the first pole piece comprises a first section and a second section which are connected with each other, the connection position of the first section and the second section is located at the inner side of the second winding tail end, the first section extends from the connection position of the first section and the second section to the first winding tail end along the winding direction, and a first concave area is arranged on one side of the first section facing the first winding tail end along the radial direction of the electrode assembly.

In the above technical scheme, because the first winding tail end exceeds the second winding tail end in the winding direction, the part adjacent to the first winding tail end is the first section of the first pole piece, and the first concave area is arranged on one side of the first section facing the first winding tail end along the radial direction of the electrode assembly, so that the first winding tail end can directly enter the first concave area of the first section when the electrode assembly expands, the better avoiding effect is achieved, and the phenomenon that the first winding tail end extrudes the adjacent first pole piece can be relieved better.

In some embodiments, the first pole piece and the second pole piece are each provided with a plurality of the first recessed areas, and the plurality of the first recessed areas of the first pole piece and the plurality of the first recessed areas of the second pole piece are each arranged along a radial direction of the electrode assembly.

In the above technical scheme, through all setting up a plurality of first sunk areas on first pole piece and second pole piece, and a plurality of first sunk areas of first pole piece and a plurality of first sunk areas of second pole piece all arrange along electrode assembly's radial, thereby a plurality of first sunk areas of first pole piece and a plurality of first sunk areas of second pole piece can provide more expansion space for first winding end in electrode assembly's radial direction, make when electrode assembly appears expanding can release the shear stress that first winding end caused adjacent first pole piece better, with the phenomenon of alleviating first winding end extrusion first pole piece that first winding end extrusion is adjacent, and then can further reduce first pole piece and appear local deformation or fracture's risk because of receiving the extrusion of first winding end.

In some embodiments, the first pole piece is a negative pole piece and the second pole piece is a positive pole piece; the second pole piece is provided with a first concave area, the first concave area of the second pole piece is located on one side of the second pole piece and the first concave area of the first pole piece facing the first concave area of the first pole piece, and the first concave area of the second pole piece covers the first concave area of the first pole piece facing the first concave area.

In the above technical scheme, the first concave area is arranged on one side of the first concave area facing the second pole piece and the first pole piece, and the first concave area of the second pole piece covers the first concave area facing the first pole piece, that is, the first concave area is correspondingly arranged on the second pole piece adjacent to the first concave area of the first pole piece along the radial direction of the electrode assembly, and in the two first concave areas facing the arrangement, the area of the first concave area arranged on the second pole piece is larger than that of the first concave area arranged on the first pole piece, namely, the area of the first concave area arranged on the positive pole piece is larger than that of the first concave area arranged on the negative pole piece.

In some embodiments, the width of the first recessed region of the second pole piece is greater than the width of the first recessed region of the first pole piece disposed facing the first recessed region of the second pole piece along the winding direction.

In the above technical scheme, the width of the first concave area of the second pole piece in the winding direction is set to be larger than the width of the first concave area of the first pole piece facing the second pole piece in the winding direction, and the electrode assembly adopting the structure can further reduce the risk of lithium precipitation of the electrode assembly in the use process on one hand, so that the use safety of the electrode assembly is improved, and on the other hand, the phenomenon of local shear stress concentration caused by the formation of a new cut-off area after the first concave area of the first pole piece and the first concave area of the second pole piece are mutually overlapped can be relieved.

In some embodiments, the second pole piece has a second winding tail end, and a second concave region is disposed on one side of the first pole piece and/or one side of the second pole piece, and a projection of the second winding tail end is located in the second concave region along the radial direction of the electrode assembly.

In the above technical scheme, the second concave area which is arranged corresponding to the second winding tail end is arranged on one side of the first pole piece and/or the second pole piece, and the projection of the second winding tail end on the radial direction of the electrode assembly falls into the second concave area, so that when the electrode assembly is expanded in the use process, the second concave area can provide enough expansion space for the second winding tail end of the second pole piece in the radial direction of the electrode assembly, so as to relieve the phenomenon that the second winding tail end presses the first pole piece or the second pole piece at the close position of the electrode assembly, and further release the shearing stress caused by the second winding tail end to the adjacent first pole piece or second pole piece, so that the shearing stress concentration phenomenon of the second winding tail end is reduced, and the local deformation or cracking risk of the first pole piece or the second pole piece of the electrode assembly due to the extrusion of the second winding tail end can be reduced, and the use safety of the electrode assembly is improved.

In some embodiments, the second recessed region has a width D in the winding direction ₂ Satisfy D ₂ ≥10mm。

In the above technical scheme, the width of the second concave region in the winding direction is set to be not less than 10mm, and since the second winding tail end can play along the winding direction due to expansion of the electrode assembly in the use process and play is within 10mm, the electrode assembly adopting the structure can ensure that the projection of the second winding tail end in the radial direction of the electrode assembly is positioned in the second concave region when the second winding tail end plays along the winding direction, so that the second concave region can stably provide expansion space for the second winding tail end.

In some embodiments, the first pole piece is a negative pole piece and the second pole piece is a positive pole piece; the outermost ring of the electrode assembly is the first pole piece, and the first winding tail end exceeds the second winding tail end along the winding direction; the first pole piece comprises a first section and a second section which are connected with each other, the connection position of the first section and the second section is positioned on the inner side of the second winding tail end, and the first section extends from the connection position of the first section and the second section to the first winding tail end along the winding direction; and the second concave area is arranged on one side of the first section, which is away from the second winding tail end, along the radial direction of the electrode assembly.

In the above technical scheme, because the first winding tail end exceeds the second winding tail end in the winding direction, the position adjacent to the second winding tail end is the first section of the first pole piece and the connection position of the first section and the second section, and the second concave area is arranged on one side, deviating from the second winding tail end, of the first section of the first pole piece.

In some embodiments, the first pole piece and the second pole piece are each provided with a plurality of the second recessed areas, and the plurality of the second recessed areas of the first pole piece and the plurality of the second recessed areas of the second pole piece are each arranged along the radial direction of the electrode assembly.

In the above technical scheme, through all setting up a plurality of second sunk areas on first pole piece and second pole piece, and a plurality of second sunk areas of first pole piece and a plurality of second sunk areas of second pole piece all arrange along electrode assembly's radial to make a plurality of second sunk areas of first pole piece and a plurality of second sunk areas of second pole piece provide more expansion space for second winding receipts tail end in electrode assembly's radial direction, make when electrode assembly appears expanding can release the second winding receipts tail end better to the shear stress that adjacent first pole piece caused, with the phenomenon of alleviating second winding receipts tail end extrusion adjacent first pole piece, and then can further reduce first pole piece and appear local deformation or fracture because of receiving the extrusion of second winding receipts tail end.

In some embodiments, the second electrode sheet is provided with the second recessed region, the second recessed region of the second electrode sheet is located on a side of the second electrode sheet facing the second recessed region of the first electrode sheet, along a radial direction of the electrode assembly, the second recessed region of the second electrode sheet covers the second recessed region of the first electrode sheet facing the first electrode sheet.

In the above technical scheme, the second concave area is arranged on one side of the second concave areas of the second pole piece and the first pole piece facing the second concave area of the first pole piece, and the second concave area of the second pole piece covers the second concave area of the first pole piece facing the arrangement, that is, the second concave areas are correspondingly arranged on the second pole piece adjacent to the second concave area of the first pole piece along the radial direction of the electrode assembly, and in the two second concave areas facing the arrangement, the area of the second concave area arranged on the second pole piece is larger than the area of the second concave area arranged on the first pole piece, that is, the area of the second concave area arranged on the positive pole piece is larger than the area of the second concave area arranged on the negative pole piece.

In some embodiments, a width of the second recessed region of the second pole piece is greater than a width of the second recessed region of the first pole piece disposed facing the second recessed region of the second pole piece along the winding direction.

In the above technical scheme, the width of the second concave area of the second pole piece in the winding direction is set to be larger than the width of the second concave area of the first pole piece facing the second concave area in the winding direction, and the electrode assembly adopting the structure can further reduce the risk of lithium precipitation of the electrode assembly in the use process on one hand, so that the use safety of the electrode assembly is improved, and on the other hand, the phenomenon of local shear stress concentration caused by the formation of a new cut-off area after the second concave area of the first pole piece and the second concave area of the second pole piece are mutually overlapped can be relieved.

In some embodiments, the first electrode sheet includes a first current collector and a first active material layer coated on at least one side of the first current collector in a radial direction of the electrode assembly; the second electrode sheet includes a second current collector and a second active material layer coated on at least one side of the second current collector in a radial direction of the electrode assembly; wherein the first recessed region of the first pole piece includes a groove provided on the first active material layer or a region of one side of the first current collector not coated with the first active material layer; the first concave region of the second pole piece comprises a groove arranged on the second active material layer or a region of one side of the second current collector, which is not coated with the second active material layer.

In the above technical solution, the first recess area disposed on the first pole piece may be a recess disposed on the first active material layer, or may be an area of the first active material layer that is not coated on one side of the first current collector, when the first recess area disposed on the first pole piece is a recess disposed on the first active material layer, the first recess area of the first pole piece may provide an expansion space for the first winding end while the energy density of the electrode assembly may be ensured, and when the first recess area disposed on the first pole piece is an area of the first active material layer that is not coated on one side of the first current collector, the first recess area of the first pole piece may provide more expansion space for the first winding end, and may be manufactured conveniently. Similarly, the first concave area arranged on the second pole piece can be a groove arranged on the second active material layer, or can be an area of one side of the second current collector, which is not coated with the second active material layer, when the first concave area arranged on the second pole piece is the groove arranged on the second active material layer, the first concave area of the second pole piece can provide expansion space for the first winding ending end and can also ensure the energy density of the electrode assembly, and when the first concave area arranged on the second pole piece is an area of one side of the second current collector, which is not coated with the second active material layer, the first concave area of the second pole piece can provide more expansion space for the first winding ending end and is convenient to manufacture.

In some embodiments, the first pole piece is a negative pole piece and the second pole piece is a positive pole piece; the first active material layer is disposed facing the second active material layer in a radial direction of the electrode assembly, and the first active material layer covers the second active material layer.

In the above technical solution, by arranging the first active material layer and the second active material layer facing in the radial direction of the electrode assembly, and arranging the first active material layer to cover the second active material layer, that is, the area of the first active material layer is larger than that of the second active material layer, the electrode assembly adopting such a structure can effectively reduce the risk of lithium precipitation of the electrode assembly during use.

In some embodiments, the electrode assembly further comprises a separator; the isolation film is arranged between the first pole piece and the second pole piece so as to separate the first pole piece and the second pole piece.

In the technical scheme, the electrode assembly is further provided with the isolating film between the first pole piece and the second pole piece, so that separation between the first pole piece and the second pole piece can be effectively realized, the phenomenon that the first pole piece and the second pole piece are short-circuited is reduced, and the potential safety hazard of the electrode assembly in the use process is reduced.

In a second aspect, embodiments of the present application further provide a battery cell including a housing and the electrode assembly described above, where the electrode assembly is housed in the housing.

In a third aspect, an embodiment of the present application further provides a battery, including a case and the battery unit described above, where the battery unit is accommodated in the case.

In a fourth aspect, an embodiment of the present application further provides an electrical device, including the above battery cell, where the battery cell is used to provide electrical energy; or a battery as described above for providing electrical energy.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

FIG. 2 is an exploded view of a battery according to some embodiments of the present application;

fig. 3 is a structural exploded view of a battery cell according to some embodiments of the present application;

FIG. 4 is a schematic view of an electrode assembly according to some embodiments of the present application;

FIG. 5 is a schematic view of an electrode assembly according to further embodiments of the present application;

fig. 6 is a schematic structural view of an electrode assembly provided in further embodiments of the present application;

fig. 7 is a partial enlarged view of a portion of the electrode assembly shown in fig. 6;

fig. 8 is a schematic structural view of an electrode assembly according to other embodiments of the present application;

fig. 9 is a schematic structural view of an electrode assembly according to still further embodiments of the present application;

fig. 10 is a partial enlarged view of the electrode assembly shown in fig. 9 at B;

FIG. 11 is a partial cross-sectional view of a first pole piece provided in accordance with still further embodiments of the present application;

FIG. 12 is a partial cross-sectional view of a first pole piece provided in yet other embodiments of the present application;

FIG. 13 is a partial cross-sectional view of a second pole piece provided in accordance with still further embodiments of the present application;

figure 14 is a partial cross-sectional view of a second pole piece provided in yet other embodiments of the present application.

Icon: 1000-vehicle; 100-cell; 10-a box body; 11-a first tank body; 12-a second tank body; 20-battery cells; 21-a housing; 211-a housing; 2111-opening; 212-end caps; 22-electrode assembly; 221-a first pole piece; 2211-first winding tail end; 2212-first segment; 2213-a second segment; 2214—a first current collector; 2215—a first active material layer; 222-a second pole piece; 2221-second winding tail end; 2222-second current collector; 2223-second active material layer; 223-a first recessed region; 224-a second recessed region; 225-a separator; 200-a controller; 300-motor; x-winding direction.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases 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.

In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "attached" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

The term "and/or" in this application is merely an association relation describing an associated object, and indicates that three relations may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In this application, the character "/" generally indicates that the associated object is an or relationship.

In the embodiments of the present application, the same reference numerals denote the same components, and in the interest of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, etc. dimensions of the various components in the embodiments of the present application, as well as the overall thickness, length, width, etc. dimensions of the integrated device, are illustrative only and should not be construed as limiting the present application in any way.

The term "plurality" as used herein refers to more than two (including two).

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiment of the present application. The battery cells may be cylindrical, flat, rectangular, or otherwise shaped, as well as the embodiments herein are not limited in this regard. The battery cells are generally classified into three types according to the packaging method: the cylindrical battery cell, the square battery cell and the soft pack battery cell are not limited thereto.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, or the like. The battery generally includes a case for enclosing one or more battery cells or a plurality of battery modules. The case body can prevent liquid or other foreign matters from affecting the charge or discharge of the battery cells.

The battery cell includes a case, an electrode assembly, and an electrolyte, and the case is used to accommodate the electrode assembly and the electrolyte. The electrode assembly consists of a positive electrode plate, a negative electrode plate and a separation film. The battery cell mainly relies on metal ions to move between the positive pole piece and the negative pole piece to work. The positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer is coated on the surface of the positive electrode current collector, and the part of the positive electrode current collector which is not coated with the positive electrode active material layer is used as a positive electrode lug so as to realize electric energy input or output of the positive electrode plate through the positive electrode lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate or the like. The negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is coated on the surface of the negative electrode current collector, and the part of the negative electrode current collector which is not coated with the negative electrode active material layer is used as a negative electrode tab so as to realize electric energy input or output of the negative electrode plate through the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the high current is passed without fusing, the number of positive electrode lugs is multiple and stacked together, and the number of negative electrode lugs is multiple and stacked together.

The battery has the outstanding advantages of high energy density, small environmental pollution, large power density, long service life, wide application range, small self-discharge coefficient and the like, and is an important component of the development of new energy sources at present. The battery cell is obtained by assembling an electrode assembly (bare cell) by winding or laminating a positive electrode plate, a negative electrode plate and a separation film, then loading the electrode assembly into a shell, and finally injecting electrolyte. The electrode assembly of the winding structure has the advantages of convenience in assembly, low manufacturing difficulty, high production efficiency and the like, and therefore, the electrode assembly of the winding structure is widely applied. However, with the continuous development of battery technology, higher demands are also being placed on the safety of use of the battery cells. Therefore, the safety in use of the electrode assembly determines the safety in use of the battery cell.

The inventors found that, in the electrode assembly of the winding type structure, the negative electrode sheet and the positive electrode sheet are generally stacked and then continuously wound, but in the electrode assembly of the winding type structure, the thicknesses of the positive electrode sheet and the negative electrode sheet are increased in the cyclic charge and discharge process, so that the expansion force of the electrode assembly is increased, and the diameters of the electrode assembly are correspondingly increased, and particularly, the expansion phenomenon of the ending cut-off position of the negative electrode sheet and the ending cut-off position of the positive electrode sheet is most obvious. However, because the expansion of the electrode assembly can be affected by the constraint of parts such as a blue film or a shell, the ending cutting-off position of the positive electrode plate or the ending cutting-off position of the negative electrode plate is easy to squeeze the electrode plate at the close position of the electrode assembly, and the phenomenon of concentrated shearing stress exists, so that the adjacent positive electrode plate or the negative electrode plate, especially the active material layer, is caused to have the risk of deformation or cracking, the phenomenon of mutual short circuit exists between the negative electrode plate and the positive electrode plate after deformation or cracking, and further the risks of short circuit, fire explosion and the like exist in the use process of the battery cell, and the use safety of the battery cell is not facilitated.

Based on the above-mentioned consideration, in order to solve the problem that there is a great potential safety hazard in the use process of the electrode assembly with the winding structure, the inventor has conducted intensive studies and has devised an electrode assembly including a first electrode sheet and a second electrode sheet with opposite polarities, the first electrode sheet and the second electrode sheet being wound in the winding direction to form the electrode assembly, the first electrode sheet having a first winding end, a first recess being provided on one side of the first electrode sheet and/or one side of the second electrode sheet, and a projection of the first winding end being located in the first recess along the radial direction of the electrode assembly.

In the electrode assembly with the structure, the first concave area which is arranged corresponding to the first winding tail end is arranged on one side of the first electrode plate and/or the second electrode plate, and the projection of the first winding tail end in the radial direction of the electrode assembly falls into the first concave area, so that when the first winding tail end of the first electrode plate is expanded in the use process of the electrode assembly, the first concave area can provide enough expansion space for the first winding tail end of the first electrode plate in the radial direction of the electrode assembly, so that the phenomenon that the first winding tail end presses the first electrode plate or the second electrode plate at the adjacent position of the electrode assembly is relieved, the shearing stress of the first winding tail end on the adjacent first electrode plate or second electrode plate can be released, the phenomenon that the shearing stress concentration occurs at the first winding tail end is reduced, the risk that the first electrode plate or the second electrode plate of the electrode assembly is locally deformed or cracked due to the extrusion of the first winding tail end is reduced, and the use safety of a battery cell with the electrode assembly is improved.

The electrode assembly disclosed in the embodiment of the application can be used in electric devices such as vehicles, ships or aircrafts, but is not limited to the use of the electrode assembly. The power supply system with the power utilization device formed by the battery monomer, the battery and the like disclosed by the application can be used, so that the potential safety hazard of the battery monomer in the use process can be effectively reduced, and the use safety of the battery monomer is improved.

The embodiment of the application provides an electricity utilization device using a battery as a power supply, wherein the electricity utilization device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft and the like. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like.

For convenience of description, the following embodiment will take an electric device according to an embodiment of the present application as an example of the vehicle 1000.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 may be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. The battery 100 is provided in the interior of the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may be used as an operating power source of the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to power the motor 300, for example, for operating power requirements during start-up, navigation, and travel of the vehicle 1000.

In some embodiments of the present application, battery 100 may not only serve as an operating power source for vehicle 1000, but may also serve as a driving power source for vehicle 1000, instead of or in part instead of fuel oil or natural gas, to provide driving power for vehicle 1000.

Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide an assembly space for the battery cells 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first case body 11 and a second case body 12, the first case body 11 and the second case body 12 being covered with each other, the first case body 11 and the second case body 12 together defining an assembly space for accommodating the battery cell 20. The second box body 12 may have a hollow structure with one end opened, the first box body 11 may have a plate-shaped structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 define an assembly space together; the first tank body 11 and the second tank body 12 may each have a hollow structure with one side opened, and the open side of the first tank body 11 may be closed to the open side of the second tank body 12. Of course, the case 10 formed by the first case body 11 and the second case body 12 may be various shapes, such as a cylinder, a rectangular parallelepiped, and the like.

In the battery 100, the plurality of battery cells 20 may be connected in series, parallel or a series-parallel connection, wherein the series-parallel connection refers to that the plurality of battery cells 20 are connected in series or parallel. The plurality of battery cells 20 can be directly connected in series or in parallel or in series-parallel, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting a plurality of battery cells 20 in series or parallel or series-parallel connection, and a plurality of battery modules are then connected in series or parallel or series-parallel connection to form a whole and are accommodated in the case 10. The battery 100 may further include other structures, for example, the battery 100 may further include a bus member for making electrical connection between the plurality of battery cells 20.

Wherein each battery cell 20 may be a secondary battery or a primary battery; but not limited to, lithium sulfur batteries, sodium ion batteries, or magnesium ion batteries. The battery cell 20 may be in the shape of a cylinder, a flat body, a rectangular parallelepiped, or other shapes, etc. Illustratively, in fig. 2, the battery cell 20 is of cylindrical configuration.

Referring to fig. 3, fig. 3 is an exploded view of a battery cell 20 according to some embodiments of the present disclosure. The battery cell 20 includes a case 21 and an electrode assembly 22, and the case 21 serves to accommodate the electrode assembly 22.

Wherein the housing 21 may also be used to contain an electrolyte, such as an electrolyte solution. The housing 21 may take a variety of structural forms. The material of the housing 21 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc.

In some embodiments, the case 21 may include a case 211 and an end cap 212, the case 211 being a hollow structure having one side opening 2111, the end cap 212 being capped at the opening 2111 of the case 211 and forming a sealing connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

In assembling the battery cell 20, the electrode assembly 22 may be placed in the case 211, the case 211 may be filled with an electrolyte, and then the end cap 212 may be covered on the opening 2111 of the case 211.

The housing 211 may be of various shapes, such as a cylinder, a rectangular parallelepiped, etc. The shape of the case 211 may be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a cylindrical housing may be selected; if the electrode assembly 22 is of a rectangular parallelepiped configuration, a rectangular parallelepiped housing may be selected. Of course, the end cap 212 may have various structures, for example, the end cap 212 has a plate-like structure, a hollow structure with one end opening 2111, and the like. Illustratively, in fig. 3, the electrode assembly 22 is of a cylindrical structure, and correspondingly, the case 211 is of a cylindrical structure, the end cap 212 is of a cylindrical plate-like structure, and the end cap 212 is capped at the opening 2111 of the case 211.

In some embodiments, the battery cell 20 may further include a positive electrode terminal mounted on the end cap 212 and a negative electrode terminal mounted on an end of the housing 211 opposite the end cap 212, although a positive electrode terminal mounted on an end of the housing 211 opposite the end cap 212 and a negative electrode terminal mounted on the end cap 212 are also possible. The positive electrode terminal and the negative electrode terminal are each used to be electrically connected with the electrode assembly 22 to achieve input or output of electric power from the battery cell 20. The positive electrode terminal and the negative electrode terminal may be directly connected to the electrode assembly 22, for example, by welding or abutting, or the like, or may be indirectly connected to the electrode assembly 22, for example, by abutting or welding the positive electrode terminal and the negative electrode terminal to the electrode assembly 22 through a current collecting member, or the like.

It is to be understood that the case 21 is not limited to the above-described structure, and the case 21 may be other structures, for example, the case 21 may include a case 211 and two end caps 212, the case 211 being a hollow structure having opposite side openings 2111, and one end cap 212 being correspondingly covered at one opening 2111 of the case 211 and forming a sealing connection to form a sealed space for accommodating the electrode assembly 22 and the electrolyte.

In some embodiments, the battery cell 20 may further include a pressure relief mechanism mounted to the end cap 212 and may also be mounted to the housing 211. The pressure release mechanism is used to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

By way of example, the pressure relief mechanism may be a component such as an explosion proof valve, an explosion proof disc, a gas valve, a pressure relief valve, or a safety valve.

The electrode assembly 22 is a member in which electrochemical reactions occur in the battery cell 20. The electrode assembly 22 may be a wound structure formed by winding two electrode sheets having opposite polarities, or a laminated structure formed by stacking two electrode sheets having opposite polarities. Illustratively, in fig. 3, the electrode assembly 22 is a wound structure formed by winding two pole pieces of opposite polarity, and the electrode assembly 22 is a cylindrical structure.

Referring to fig. 3, and further referring to fig. 4 and 5, fig. 4 is a schematic structural view of an electrode assembly 22 according to some embodiments of the present application, and fig. 5 is a schematic structural view of an electrode assembly 22 according to still other embodiments of the present application. The application provides an electrode assembly 22, the electrode assembly 22 comprises a first pole piece 221 and a second pole piece 222 with opposite polarities, the first pole piece 221 and the second pole piece 222 are wound along a winding direction X to form the electrode assembly 22, and the first pole piece 221 is provided with a first winding tail end 2211. Wherein, a side of the first pole piece 221 and/or a side of the second pole piece 222 is provided with a first concave region 223, and a projection of the first winding ending end 2211 is located in the first concave region 223 along a radial direction of the electrode assembly 22.

The winding direction X is unidirectional, that is, the winding direction X is a direction in which the first pole piece 221 and the second pole piece 222 are continuously wound from inside to outside.

Alternatively, the first electrode tab 221 and the second electrode tab 222 may be a negative electrode tab and a positive electrode tab, respectively, or may be a positive electrode tab and a negative electrode tab, respectively. Illustratively, in fig. 4, the first electrode tab 221 is a negative electrode tab, the second electrode tab 222 is a positive electrode tab, and the outermost ring of the electrode assembly 22 is the first electrode tab 221 (negative electrode tab). Of course, in some embodiments, as shown in fig. 5, the first electrode piece 221 may also be a positive electrode piece, and the corresponding second electrode piece 222 is a negative electrode piece, and the outermost ring of the electrode assembly 22 is the second electrode piece 222 (negative electrode piece).

The first winding tail 2211 is the cutting position of the winding tail of the first pole piece 221.

One side of the first pole piece 221 and/or one side of the second pole piece 222 are provided with a first concave area 223, namely, the first pole piece 221 is provided with the first concave area 223, the second pole piece 222 is provided with the first concave area 223, and the first pole piece 221 and the second pole piece 222 are provided with the first concave area 223. Illustratively, in fig. 4, since the first pole piece 221 is a negative pole piece, a first concave region 223 is disposed on a side of the first pole piece 221 adjacent to the first winding end 2211 facing the first winding end, however, in other embodiments, a first concave region 223 may be disposed on a side of the second pole piece 222 corresponding to the first winding end 2211 along the radial direction of the electrode assembly 22, and similarly, a plurality of first concave regions 223 may be disposed on both the first pole piece 221 and the second pole piece 222 along the radial direction of the electrode assembly 22. For example, in fig. 5, since the first electrode sheet 221 is a positive electrode sheet, a first concave region 223 is disposed on a side of the second electrode sheet 222 located outside the first winding end 2211 facing away from the first winding end 2211, however, in other embodiments, a first concave region 223 may be disposed on a side of the first electrode sheet 221 corresponding to the first winding end 2211 in the radial direction of the electrode assembly 22, and similarly, a plurality of first concave regions 223 may be disposed on both the first electrode sheet 221 and the second electrode sheet 222 in the radial direction of the electrode assembly 22.

In the radial direction of the electrode assembly 22, the projection of the first winding tail 2211 is located in the first concave region 223, i.e., in the direction in which the center of the electrode assembly 22 is directed toward the edge of the electrode assembly 22 or in the direction in which the edge of the electrode assembly 22 is directed toward the center of the electrode assembly 22, the first winding tail 2211 is disposed corresponding to the first concave region 223, that is, in the radial direction of the electrode assembly 22, the first concave region 223 covers the first winding tail 2211.

By arranging the first concave region 223 on one side of the first pole piece 221 and/or the second pole piece 222, which is arranged corresponding to the first winding tail end 2211, and the projection of the first winding tail end 2211 in the radial direction of the electrode assembly 22 falls into the first concave region 223, when the electrode assembly 22 expands in use, the first concave region 223 can provide enough expansion space for the first winding tail end 2211 of the first pole piece 221 in the radial direction of the electrode assembly 22, so as to relieve the phenomenon that the first winding tail end 2211 presses the first pole piece 221 or the second pole piece 222 of the adjacent position of the electrode assembly 22, thereby releasing the shearing stress caused by the first winding tail end 2211 to the adjacent first pole piece 221 or the second pole piece 222, reducing the phenomenon that the shearing stress is concentrated at the first winding tail end 2211, further reducing the risk that the first pole piece 221 or the second pole piece 222 of the electrode assembly 22 is locally deformed or cracked due to the pressing of the first winding tail end 2211, and being beneficial to improving the safety of the battery assembly 22.

According to some embodiments of the present application, referring to fig. 4, the width of the first recessed area 223 along the winding direction X is D ₁ Satisfy D ₁ ≥10mm。

Wherein D is ₁ 10mm or more, i.e., the first recessed area 223 has a dimension in the winding direction X of 10mm or more. Exemplary, dimension D of the first recessed area 223 in the winding direction X ₁ May be 10mm, 12mm, 15mm, 18mm, 20mm, etc.

By setting the width of the first recess region 223 in the winding direction X to be not less than 10mm, since the first winding end 2211 is shifted in the winding direction X due to expansion of the electrode assembly 22 during use and is shifted within 10mm, the electrode assembly 22 adopting this structure can ensure that the projection of the first winding end 2211 in the radial direction of the electrode assembly 22 is positioned in the first recess region 223 when the first winding end 2211 is shifted in the winding direction X, so that the first recess region 223 can stably provide the expansion space for the first winding end 2211.

In accordance with some embodiments of the present application, with continued reference to fig. 4, the outermost ring of the electrode assembly 22 is the first pole piece 221, the second pole piece 222 has a second winding tail end 2221, and the first winding tail end 2211 extends beyond the second winding tail end 2221 in the winding direction X. The first pole piece 221 includes a first segment 2212 and a second segment 2213 that are connected to each other, a connection position of the first segment 2212 and the second segment 2213 is located inside the second winding tail end 2221, the first segment 2212 extends from the connection position of the first segment 2212 and the second segment 2213 to the first winding tail end 2211 along the winding direction X, and a first concave region 223 is provided on a side of the first segment 2212 facing the first winding tail end 2211 in a radial direction of the electrode assembly 22.

The first electrode piece 221 is a negative electrode piece, the second electrode piece 222 is a positive electrode piece, and the first winding tail end 2211 extends beyond the second winding tail end 2221 along the winding direction X, that is, the first electrode piece 221 (negative electrode piece) located at the outermost ring of the electrode assembly 22 wraps the second winding tail end 2221 of the second electrode piece 222 (positive electrode piece), and the second winding tail end 2221 is the cutting position of the winding tail of the second electrode piece 222.

The first segment 2212 of the first pole piece 221 is a portion extending from a connection position of the first segment 2212 and the second segment 2213 to the first winding end 2211 in the winding direction X, the second segment 2213 of the first pole piece 221 is a portion extending from a connection position of the first segment 2212 and the second segment 2213 to a central position of the electrode assembly 22 in a reverse direction of the winding direction X, and the connection position of the first segment 2212 and the second segment 2213 is adjacent to the second winding end 2221 in a radial direction of the electrode assembly 22 and is located inside the second winding end 2221.

Along the radial direction of the electrode assembly 22, a side of the first segment 2212 facing the first winding end 2211 is provided with a first concave region 223, i.e., in the radial direction of the electrode assembly 22, a side of the first pole piece 221 adjacent to the first winding end 2211 facing the first winding end 2211 is provided with a first concave region 223.

Since the first winding tail end 2211 exceeds the second winding tail end 2221 in the winding direction X, the position adjacent to the first winding tail end 2211 is the first section 2212 of the first pole piece 221, and the first concave region 223 is arranged on one side of the first section 2212 facing the first winding tail end 2211 along the radial direction of the electrode assembly 22, so that the first winding tail end 2211 can directly enter the first concave region 223 of the first section 2212 when the electrode assembly 22 expands, a better avoiding effect is achieved, and the phenomenon that the first winding tail end 2211 extrudes the adjacent first pole piece 221 can be relieved better.

Referring to fig. 6, fig. 6 is a schematic structural view of an electrode assembly 22 according to further embodiments of the present application. The first and second electrode sheets 221 and 222 are each provided with a plurality of first recess regions 223, and the plurality of first recess regions 223 of the first electrode sheet 221 and the plurality of first recess regions 223 of the second electrode sheet 222 are each arranged in the radial direction of the electrode assembly 22.

The first pole piece 221 and the second pole piece 222 are provided with a plurality of first recessed areas 223, that is, the first pole piece 221 is provided with a plurality of first recessed areas 223 arranged along the radial direction of the electrode assembly 22, and the second pole piece 222 is also provided with a plurality of first recessed areas 223 arranged along the radial direction of the electrode assembly 22.

By arranging the plurality of first concave areas 223 on the first pole piece 221 and the second pole piece 222, and arranging the plurality of first concave areas 223 of the first pole piece 221 and the plurality of first concave areas 223 of the second pole piece 222 along the radial direction of the electrode assembly 22, the plurality of first concave areas 223 of the first pole piece 221 and the plurality of first concave areas 223 of the second pole piece 222 can provide more expansion space for the first winding ending end 2211 in the radial direction of the electrode assembly 22, so that the shearing stress of the first winding ending end 2211 to the adjacent first pole piece 221 caused by the expansion of the electrode assembly 22 can be better released, the phenomenon that the first winding ending end 2211 extrudes the adjacent first pole piece 221 is relieved, and the risk that the first pole piece 221 is locally deformed or cracked due to the extrusion of the first winding ending end 2211 can be further reduced.

Referring to fig. 6, and with further reference to fig. 7, fig. 7 is an enlarged view of a portion of the electrode assembly 22 shown in fig. 6, according to some embodiments of the present application. The first pole piece 221 is a negative pole piece, and the second pole piece 222 is a positive pole piece. The second electrode plate 222 is provided with a first concave region 223, and the first concave region 223 of the second electrode plate 222 is located on a side of the second electrode plate 222 facing the first concave region 223 of the first electrode plate 221 along the radial direction of the electrode assembly 22, and the first concave region 223 of the second electrode plate 222 covers the first concave region 223 of the first electrode plate 221 facing the first electrode plate 221.

The first concave area 223 of the second pole piece 222 is located on a side of the second pole piece 222 facing the first concave area 223 of the first pole piece 221 along the radial direction of the electrode assembly 22, that is, on a side of the second pole piece 222 facing the first concave area 223 of the first pole piece 221 along the radial direction of the electrode assembly 22, the first concave area 223 is disposed, that is, the first concave area 223 disposed on the second pole piece 222 and the first concave area 223 disposed on the first pole piece 221 are disposed along the radial direction of the electrode assembly 22.

The first concave region 223 of the second pole piece 222 covers the first concave region 223 of the first pole piece 221 facing the arrangement, that is, in the two first concave regions 223 facing the arrangement, the area of the first concave region 223 arranged on the second pole piece 222 is larger than the area of the first concave region 223 arranged on the first pole piece 221, that is, the area of the first concave region 223 arranged on the positive pole piece is larger than the area of the first concave region 223 arranged on the negative pole piece.

By arranging the first concave region 223 on the side, facing the first concave region 223, of the second pole piece 222 and the first pole piece 221, and covering the first concave region 223, facing the first pole piece 221, of the second pole piece 222, the risk of lithium precipitation of the electrode assembly 22 can be effectively relieved while enough expansion space is provided for the first winding ending end 2211 by adopting the structure, so that potential safety hazards of the electrode assembly 22 in the use process are reduced.

In some embodiments, as shown in fig. 6 and 7, the width of the first recessed area 223 of the second pole piece 222 is greater than the width of the first recessed area 223 of the first pole piece 221 disposed facing the first recessed area 223 of the second pole piece 222 along the winding direction X.

In the above description, that is, in the two first depressed regions 223 disposed facing each other, the size of the first depressed region 223 disposed on the second pole piece 222 in the winding direction X is larger than the size of the first depressed region 223 disposed on the first pole piece 221 in the winding direction X, so that the two end walls of the first depressed region 223 disposed on the first pole piece 221 in the winding direction X are offset from the two end walls of the first depressed region 223 disposed on the second pole piece 222 in the winding direction X.

By setting the width of the first concave region 223 of the second pole piece 222 in the winding direction X to be larger than the width of the first concave region 223 of the first pole piece 221 facing the first pole piece, the electrode assembly 22 adopting the structure can further reduce the risk of lithium precipitation of the electrode assembly 22 in the use process so as to improve the use safety of the electrode assembly 22, and can relieve the phenomenon of local shear stress concentration caused by the formation of a new cut-off region after the first concave region 223 of the first pole piece 221 and the first concave region 223 of the second pole piece 222 are overlapped with each other.

Referring to fig. 8, fig. 8 is a schematic structural view of an electrode assembly 22 according to other embodiments of the present application. The second pole piece 222 has a second winding tail 2221, and a second concave region 224 is provided on one side of the first pole piece 221 and/or one side of the second pole piece 222, and a projection of the second winding tail 2221 is located in the second concave region 224 along a radial direction of the electrode assembly 22.

Alternatively, the first electrode tab 221 and the second electrode tab 222 may be a negative electrode tab and a positive electrode tab, respectively, or may be a positive electrode tab and a negative electrode tab, respectively. Illustratively, in fig. 8, the first electrode tab 221 is a negative electrode tab, the second electrode tab 222 is a positive electrode tab, and the outermost ring of the electrode assembly 22 is the first electrode tab 221 (negative electrode tab). Of course, in other embodiments, the electrode assembly 22 may have other structures, such as the first electrode 221 being a positive electrode and the second electrode 222 being a negative electrode.

The second winding tail 2221 is the cut-off position of the second pole piece 222 for winding tail.

A second concave area 224 is arranged on one side of the first pole piece 221 and/or one side of the second pole piece 222, namely, the second concave area 224 is arranged on the first pole piece 221, the second concave area 224 is also arranged on the second pole piece 222, and the second concave area 224 is also arranged on both the first pole piece 221 and the second pole piece 222. Illustratively, in fig. 8, since the first pole piece 221 is a negative pole piece, a second concave region 224 is disposed on a side of the first pole piece 221 adjacent to the second winding end 2221 facing away from the second winding end, and of course, in other embodiments, a first concave region 223 may be disposed on a side of the second pole piece 222 corresponding to the first winding end 2211 along the radial direction of the electrode assembly 22, and similarly, a plurality of first concave regions 223 may be disposed on both the first pole piece 221 and the second pole piece 222 along the radial direction of the electrode assembly 22.

The projection of the second winding tail 2221 is located in the second concave region 224 in the radial direction of the electrode assembly 22, i.e., in the direction in which the center of the electrode assembly 22 is directed toward the edge of the electrode assembly 22 or in the direction in which the edge of the electrode assembly 22 is directed toward the center of the electrode assembly 22, the second winding tail 2221 is disposed corresponding to the second concave region 224, that is, the second concave region 224 covers the second winding tail 2221 in the radial direction of the electrode assembly 22.

By arranging the second concave area 224 which is arranged corresponding to the second winding tail end 2221 on one side of the first pole piece 221 and/or the second pole piece 222, and the projection of the second winding tail end 2221 in the radial direction of the electrode assembly 22 falls into the second concave area 224, when the electrode assembly 22 expands in use, the second concave area 224 can provide enough expansion space for the second winding tail end 2221 of the second pole piece 222 in the radial direction of the electrode assembly 22 so as to relieve the phenomenon that the second winding tail end 2221 presses the first pole piece 221 or the second pole piece 222 of the adjacent part of the electrode assembly 22, thereby releasing the shearing stress caused by the second winding tail end 2221 to the adjacent first pole piece 221 or second pole piece 222, reducing the occurrence of the phenomenon that the shearing stress is concentrated on the second winding tail end 2221, and further reducing the occurrence of local deformation or cracking of the first pole piece 221 or the second pole piece 222 of the electrode assembly 22 due to the pressing of the second winding tail end 2221, so as to improve the use safety of the electrode assembly 22.

According to some embodiments of the present application, referring to fig. 8, the width of the second recessed area 224 is D along the winding direction X ₂ Satisfy D ₂ ≥10mm。

Wherein D is ₂ Not less than 10mm, i.e., the second recessed area 224 has a dimension in the winding direction X of 10mm or more. Exemplary, the second recessDimension D of region 224 in winding direction X ₂ May be 10mm, 12mm, 15mm, 18mm, 20mm, etc.

By setting the width of the second concave region 224 in the winding direction X to be not less than 10mm, since the second winding tail end 2221 is shifted in the winding direction X due to expansion of the electrode assembly 22 during use and is shifted within 10mm, the electrode assembly 22 adopting this structure can ensure that the projection of the second winding tail end 2221 in the radial direction of the electrode assembly 22 is positioned in the second concave region 224 when the second winding tail end 2221 is shifted in the winding direction X, so that the second concave region 224 can stably provide the expansion space for the second winding tail end 2221.

According to some embodiments of the present application, referring to fig. 8, the first electrode tab 221 is a negative electrode tab, and the second electrode tab 222 is a positive electrode tab. The outermost ring of the electrode assembly 22 is the first electrode sheet 221, and the first winding tail 2211 extends beyond the second winding tail 2221 in the winding direction X. The first pole piece 221 includes a first segment 2212 and a second segment 2213 connected to each other, a connection position of the first segment 2212 and the second segment 2213 is located inside the second winding tail end 2221, and the first segment 2212 extends from the connection position of the first segment 2212 and the second segment 2213 to the first winding tail end 2211 along the winding direction X. In the radial direction of the electrode assembly 22, a side of the first segment 2212 facing away from the second winding tail end 2221 is provided with a second recessed area 224.

Wherein, along the winding direction X, the first winding tail end 2211 exceeds the second winding tail end 2221, that is, the first electrode tab 221 (negative electrode tab) located at the outermost ring of the electrode assembly 22 wraps the second winding tail end 2221 of the second electrode tab 222 (positive electrode tab).

In the radial direction of the electrode assembly 22, a second concave region 224 is disposed on a side of the first segment 2212 facing away from the second winding tail end 2221, that is, in the radial direction of the electrode assembly 22, a second concave region 224 is disposed on a side of the first pole piece 221 adjacent to the second winding tail end 2221 and located outside the second winding tail end 2221 facing away from the second winding tail end 2221.

Since the first winding tail end 2211 exceeds the second winding tail end 2221 in the winding direction X, the position adjacent to the second winding tail end 2221 is the connection position of the first segment 2212 and the first segment 2212 of the first pole piece 221 and the second segment 2213, by arranging the second concave area 224 on the side, away from the second winding tail end 2221, of the first segment 2212 of the first pole piece 221, the second concave area 224 for providing an expansion space for the second winding tail end 2221 is arranged on the first pole piece 221 adjacent to the second winding tail end 2221 by adopting the structure, and the risk of lithium precipitation of the electrode assembly 22 in the use process can be reduced while the better avoidance effect on the second winding tail end 2221 is realized.

Referring to fig. 9, fig. 9 is a schematic structural view of an electrode assembly 22 according to still other embodiments of the present application. The first and second electrode sheets 221 and 222 are each provided with a plurality of second recessed areas 224, and the plurality of second recessed areas 224 of the first electrode sheet 221 and the plurality of second recessed areas 224 of the second electrode sheet 222 are each arranged in the radial direction of the electrode assembly 22.

The first pole piece 221 and the second pole piece 222 are provided with a plurality of second recessed areas 224, that is, the first pole piece 221 is provided with a plurality of second recessed areas 224 arranged along the radial direction of the electrode assembly 22, and the second pole piece 222 is also provided with a plurality of second recessed areas 224 arranged along the radial direction of the electrode assembly 22.

By arranging the plurality of second concave regions 224 on the first pole piece 221 and the second pole piece 222, and arranging the plurality of second concave regions 224 of the first pole piece 221 and the plurality of second concave regions 224 of the second pole piece 222 along the radial direction of the electrode assembly 22, the plurality of second concave regions 224 of the first pole piece 221 and the plurality of second concave regions 224 of the second pole piece 222 can provide more expansion space for the second winding tail end 2221 in the radial direction of the electrode assembly 22, so that the shearing stress of the second winding tail end 2221 to the adjacent first pole piece 221 caused by the expansion of the electrode assembly 22 can be better released, the phenomenon that the second winding tail end 2221 extrudes the adjacent first pole piece 221 is relieved, and the risk that the first pole piece 221 is locally deformed or cracked due to the extrusion of the second winding tail end 2221 can be further reduced.

Referring to fig. 9, and with further reference to fig. 10, fig. 10 is an enlarged view of a portion at B of the electrode assembly 22 shown in fig. 9, in accordance with some embodiments of the present application. The second electrode plate 222 is provided with a second concave region 224, and the second concave region 224 of the second electrode plate 222 is located on a side of the second electrode plate 222 facing the second concave region 224 of the first electrode plate 221 along the radial direction of the electrode assembly 22, and the second concave region 224 of the second electrode plate 222 covers the second concave region 224 of the first electrode plate 221 facing the first electrode plate 221.

The second concave region 224 of the second pole piece 222 is located on a side of the second pole piece 222 facing the second concave region 224 of the first pole piece 221 along the radial direction of the electrode assembly 22, that is, on a side of the second pole piece 222 facing the second concave region 224 of the first pole piece 221 along the radial direction of the electrode assembly 22, the second concave region 224 is located, that is, the second concave region 224 located on the second pole piece 222 and the second concave region 224 located on the first pole piece 221 are located along the radial direction of the electrode assembly 22.

The second concave region 224 of the second pole piece 222 covers the second concave region 224 of the first pole piece 221 disposed facing, that is, in the two second concave regions 224 disposed facing, the area of the second concave region 224 disposed on the second pole piece 222 is larger than the area of the second concave region 224 disposed on the first pole piece 221, that is, the area of the second concave region 224 disposed on the positive pole piece is larger than the area of the second concave region 224 disposed on the negative pole piece.

By arranging the second concave region 224 on the side, facing the second concave region 224, of the second pole piece 222 and the first pole piece 221, and covering the second concave region 224 of the first pole piece 221 facing the second concave region 224, the risk of lithium precipitation of the electrode assembly 22 can be effectively relieved while enough expansion space is provided for the second winding ending end 2221, so that potential safety hazards of the electrode assembly 22 in use are reduced.

In some embodiments, as shown in fig. 9 and 10, the width of the second recessed area 224 of the second pole piece 222 is greater than the width of the second recessed area 224 of the first pole piece 221 disposed facing the second recessed area 224 of the second pole piece 222 along the winding direction X.

In the above description, that is, in the two second depressed regions 224 disposed facing each other, the size of the second depressed region 224 disposed on the second pole piece 222 in the winding direction X is larger than the size of the second depressed region 224 disposed on the first pole piece 221 in the winding direction X, so that the two end walls of the second depressed region 224 disposed on the first pole piece 221 in the winding direction X are offset from the two end walls of the second depressed region 224 disposed on the second pole piece 222 in the winding direction X.

By setting the width of the second concave region 224 of the second pole piece 222 in the winding direction X to be larger than the width of the second concave region 224 of the first pole piece 221 facing the second pole piece, the electrode assembly 22 adopting such a structure can further reduce the risk of lithium precipitation of the electrode assembly 22 in the use process so as to improve the use safety of the electrode assembly 22, and can relieve the phenomenon of local shear stress concentration caused by the formation of a new cut-off region after the second concave region 224 of the first pole piece 221 and the second concave region 224 of the second pole piece 222 overlap each other.

According to some embodiments of the present application, referring to fig. 11-14, fig. 11 is a partial cross-sectional view of a first pole piece 221 provided in still other embodiments of the present application, fig. 12 is a partial cross-sectional view of a first pole piece 221 provided in still other embodiments of the present application, fig. 13 is a partial cross-sectional view of a second pole piece 222 provided in still other embodiments of the present application, and fig. 14 is a partial cross-sectional view of a second pole piece 222 provided in still other embodiments of the present application. The first electrode tab 221 includes a first current collector 2214 and a first active material layer 2215 coated on at least one side of the first current collector 2214 in the radial direction of the electrode assembly 22. The second electrode sheet 222 includes a second current collector 2222 and a second active material layer 2223 coated on at least one side of the second current collector 2222 in the radial direction of the electrode assembly 22. Wherein, the first recess region 223 of the first electrode tab 221 includes a groove (as shown in fig. 12) provided on the first active material layer 2215 or a region (as shown in fig. 11) of the first current collector 2214 where one side of the first current collector 2214 is not coated with the first active material layer 2215. The first recess region 223 of the second electrode tab 222 includes a groove (as shown in fig. 14) provided on the second active material layer 2223 or a region (as shown in fig. 13) where one side of the second current collector 2222 is not coated with the second active material layer 2223.

Illustratively, the first pole piece 221 is a negative pole piece and the second pole piece 222 is a positive pole piece. The first active material layer 2215 is a negative active material coated on the first current collector 2214, and is used for electrochemical reaction, and the material of the first active material layer 2215 may be carbon or silicon, and the material of the first current collector 2214 may be copper, and the like. The second active material layer 2223 is a positive electrode active material coated on the second current collector 2222 for electrochemical reaction, and the material of the second active material layer 2223 may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like, and the material of the second current collector 2222 may be aluminum or the like.

In fig. 11, the first concave region 223 of the first electrode sheet 221 is a region where one side of the first current collector 2214 is not coated with the first active material layer 2215, i.e., the first concave region 223 of the first electrode sheet 221 is a blank region on the first current collector 2214, which is not coated with the first active material layer 2215.

In fig. 12, the first concave region 223 of the first pole piece 221 is a groove disposed on the first active material layer 2215, that is, the first concave region 223 of the first pole piece 221 is a weak region disposed on the first active material layer 2215, and the thickness of the first active material layer 2215 located in the weak region is smaller than that of the first active material layer 2215 in other regions. Preferably, the thickness of the first active material layer 2215 located at the weak area is not more than 60% of the thickness of the first active material layer 2215 at the other area.

In fig. 13, the first concave region 223 of the second electrode tab 222 is a region where one side of the second current collector 2222 is not coated with the second active material layer 2223, i.e., the first concave region 223 of the second electrode tab 222 is a blank region on the second current collector 2222, which is not coated with the second active material layer 2223.

In fig. 14, the first concave region 223 of the second electrode plate 222 is a groove disposed on the second active material layer 2223, that is, the first concave region 223 of the second electrode plate 222 is a weak region disposed on the second active material layer 2223, and the thickness of the second active material layer 2223 located in the weak region is smaller than the thickness of the second active material layer 2223 in other regions. Preferably, the thickness of the second active material layer 2223 located at the weak area is not more than 60% of the thickness of the second active material layer 2223 located at the other areas.

Illustratively, in fig. 11, both sides of the first current collector 2214 of the first electrode tab 221 are coated with the first active material layer 2215, however, in other embodiments, the first active material layer 2215 may be coated on only one side of the first current collector 2214.

Illustratively, in fig. 13, both sides of the second current collector 2222 of the second electrode tab 222 are coated with the second active material layer 2223, however, in other embodiments, only one side of the second current collector 2222 may be coated with the second active material layer 2223.

It should be noted that the second recess area 224 of the first electrode tab 221 may also include a groove provided on the first active material layer 2215 or an area of one side of the first current collector 2214 where the first active material layer 2215 is not coated. Likewise, the second recess region 224 of the second electrode tab 222 may also include a groove provided on the second active material layer 2223 or a region of the side of the second current collector 2222 that is not coated with the second active material layer 2223.

The first concave region 223 disposed on the first pole piece 221 may be a groove disposed on the first active material layer 2215, or may be a region where the first active material layer 2215 is not coated on one side of the first current collector 2214, so that the first concave region 223 of the first pole piece 221 can provide an expansion space for the first winding end 2211 when the first concave region 223 disposed on the first pole piece 221 is a groove disposed on the first active material layer 2215, and can also ensure the energy density of the electrode assembly 22, and can provide more expansion space for the first winding end 2211 when the first concave region 223 disposed on the first pole piece 221 is a region where the first active material layer 2215 is not coated on one side of the first current collector 2214, and is convenient for manufacturing. Similarly, the first recess region 223 disposed on the second electrode tab 222 may be a recess disposed on the second active material layer 2223, or may be a region where the second active material layer 2223 is not coated on one side of the second current collector 2222, so that the first recess region 223 of the second electrode tab 222 can provide an expansion space for the first winding tail 2211 when the first recess region 223 disposed on the second electrode tab 222 is a recess disposed on the second active material layer 2223, and can also ensure energy density of the electrode assembly 22, and can provide more expansion space for the first winding tail 2211 when the first recess region 223 disposed on the second electrode tab 222 is a region where the second active material layer 2223 is not coated on one side of the second current collector 2222, and is convenient for manufacturing.

In some embodiments, the first pole piece 221 is a negative pole piece and the second pole piece 222 is a positive pole piece. Along the radial direction of the electrode assembly 22, the first active material layer 2215 is disposed facing the second active material layer 2223, and the first active material layer 2215 covers the second active material layer 2223.

Wherein the first active material layer 2215 covers the second active material layer 2223, i.e. the area of the first active material layer 2215 of the first pole piece 221 is larger than the area of the second active material layer 2223 of the second pole piece 222.

By disposing the first active material layer 2215 and the second active material layer 2223 facing in the radial direction of the electrode assembly 22 and disposing the first active material layer 2215 so as to cover the second active material layer 2223, the electrode assembly 22 adopting such a structure can effectively reduce the risk of occurrence of lithium precipitation of the electrode assembly 22 during use.

According to some embodiments of the present application, referring to fig. 4, the electrode assembly 22 further includes a separator 225, the separator 225 being disposed between the first and second electrode sheets 221 and 222 to separate the first and second electrode sheets 221 and 222.

The isolating film 225 plays a role of insulating and isolating the first pole piece 221 and the second pole piece 222, and the isolating film 225 can be made of various materials. Illustratively, the material of the separator 225 may be PP (polypropylene) or PE (polyethylene), etc.

The electrode assembly 22 is further provided with a separation film 225 located between the first pole piece 221 and the second pole piece 222, so that separation between the first pole piece 221 and the second pole piece 222 can be effectively achieved, the phenomenon that the first pole piece 221 and the second pole piece 222 are short-circuited is reduced, and potential safety hazards of the electrode assembly 22 in the use process are reduced.

According to some embodiments of the present application, there is also provided a battery cell 20 including a case 21 and the electrode assembly 22 of any of the above aspects, the electrode assembly 22 being accommodated in the case 21.

According to some embodiments of the present application, there is further provided a battery 100, where the battery 100 includes a case 10 and a battery cell 20 according to any one of the above aspects, and the battery cell 20 is accommodated in the case 10.

According to some embodiments of the present application, there is further provided an electric device, the electric device including the battery cell 20 of any one of the above aspects, and the battery cell 20 being configured to provide electric energy to the electric device; alternatively, the power consumption device includes the battery 100 of any of the above aspects, and the battery 100 is used to supply the power consumption device with electric power.

The powered device may be any of the aforementioned devices or systems employing either the battery cells 20 or the battery 100.

In accordance with some embodiments of the present application, referring to fig. 9 and 10, there is provided an electrode assembly 22, the electrode assembly 22 including a first electrode sheet 221, a second electrode sheet 222, and a separator 225. The first pole piece 221 is a negative pole piece, the second pole piece 222 is a positive pole piece, and the isolating film 225 is disposed between the first pole piece 221 and the second pole piece 222 to separate the first pole piece 221 and the second pole piece 222. The first and second electrode sheets 221 and 222 are wound in the winding direction X to form the electrode assembly 22, the electrodeThe outermost turn of the assembly 22 is a first pole piece 221, the first pole piece 221 having a first winding tail 2211 and the second pole piece 222 having a second winding tail 2221, the first winding tail 2211 extending beyond the second winding tail 2221 in the winding direction X. The first pole piece 221 includes a first segment 2212 and a second segment 2213 connected to each other, a connection position of the first segment 2212 and the second segment 2213 is located inside the second winding tail end 2221, and the first segment 2212 extends from the connection position of the first segment 2212 and the second segment 2213 to the first winding tail end 2211 along the winding direction X. Along the radial direction of the electrode assembly 22, a side of the first segment 2212 facing the first winding tail 2211 is provided with a first concave region 223, and a projection of the first winding tail 2211 is located in the first concave region 223. Along the radial direction of the electrode assembly 22, a side of the first segment 2212 facing away from the second winding tail 2221 is provided with a second concave region 224, and a projection of the second winding tail 2221 is located in the second concave region 224. The first pole piece 221 and the second pole piece 222 are respectively provided with a plurality of first concave areas 223, the plurality of first concave areas 223 of the first pole piece 221 and the plurality of first concave areas 223 of the second pole piece 222 are respectively distributed along the radial direction of the electrode assembly 22, the first concave areas 223 of the second pole piece 222 are positioned on one side of the second pole piece 222 facing the first concave areas 223 of the first pole piece 221, and the first concave areas 223 of the second pole piece 222 cover the first concave areas 223 of the first pole piece 221 facing the first pole piece 221. The first pole piece 221 and the second pole piece 222 are respectively provided with a plurality of second concave areas 224, the plurality of second concave areas 224 of the first pole piece 221 and the plurality of second concave areas 224 of the second pole piece 222 are respectively distributed along the radial direction of the electrode assembly 22, the second concave areas 224 of the second pole piece 222 are positioned on one side of the second pole piece 222 facing the second concave areas 224 of the first pole piece 221, and the second concave areas 224 of the second pole piece 222 cover the second concave areas 224 of the first pole piece 221 facing the arrangement. Wherein, along the winding direction X, the width of the first concave area 223 is D ₁ The width of the second recess 224 is D ₂ Satisfy D ₁ ≥10mm，D ₂ ≥10mm。

It should be noted that, without conflict, the embodiments and features of the embodiments in the present application may be combined with each other.

The foregoing is merely a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and variations may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

An electrode assembly comprising a first pole piece and a second pole piece of opposite polarity, the first pole piece and the second pole piece being wound in a winding direction to form the electrode assembly, the first pole piece having a first winding tail end;

and the projection of the tail end of the first winding is positioned in the first concave area along the radial direction of the electrode assembly.
The electrode assembly of claim 1, wherein the width of the first recessed region along the winding direction is D ₁ Satisfy D ₁ ≥10mm。
The electrode assembly according to claim 1 or 2, wherein the outermost ring of the electrode assembly is the first pole piece, the second pole piece has a second winding tail end, and the first winding tail end exceeds the second winding tail end in the winding direction;

The first pole piece comprises a first section and a second section which are connected with each other, the connection position of the first section and the second section is located at the inner side of the second winding tail end, the first section extends from the connection position of the first section and the second section to the first winding tail end along the winding direction, and a first concave area is arranged on one side of the first section facing the first winding tail end along the radial direction of the electrode assembly.
The electrode assembly of claim 3, wherein the first and second electrode sheets are each provided with a plurality of the first recessed regions, the plurality of first recessed regions of the first electrode sheet and the plurality of first recessed regions of the second electrode sheet are each arranged in a radial direction of the electrode assembly.
The electrode assembly of claim 3 or 4, wherein the first electrode sheet is a negative electrode sheet and the second electrode sheet is a positive electrode sheet;

the second pole piece is provided with a first concave area, the first concave area of the second pole piece is located on one side of the second pole piece and the first concave area of the first pole piece facing the first concave area of the first pole piece, and the first concave area of the second pole piece covers the first concave area of the first pole piece facing the first concave area.
The electrode assembly of claim 5, wherein a width of the first recessed region of the second pole piece is greater than a width of the first recessed region of the first pole piece disposed facing the first recessed region of the second pole piece in the winding direction.
The electrode assembly of any one of claims 1-6, wherein the second pole piece has a second winding tail end, a side of the first pole piece and/or a side of the second pole piece is provided with a second recessed region, and a projection of the second winding tail end is located in the second recessed region along a radial direction of the electrode assembly.
The electrode assembly of claim 7, wherein the width of the second recessed region along the winding direction is D ₂ Satisfy D ₂ ≥10mm。
The electrode assembly of claim 7 or 8, wherein the first electrode sheet is a negative electrode sheet and the second electrode sheet is a positive electrode sheet;

the outermost ring of the electrode assembly is the first pole piece, and the first winding tail end exceeds the second winding tail end along the winding direction;

the first pole piece comprises a first section and a second section which are connected with each other, the connection position of the first section and the second section is positioned on the inner side of the second winding tail end, and the first section extends from the connection position of the first section and the second section to the first winding tail end along the winding direction;

And the second concave area is arranged on one side of the first section, which is away from the second winding tail end, along the radial direction of the electrode assembly.
The electrode assembly of claim 9, wherein the first and second electrode sheets are each provided with a plurality of the second recessed regions, the plurality of the second recessed regions of the first electrode sheet and the plurality of the second recessed regions of the second electrode sheet each being arranged in a radial direction of the electrode assembly.
The electrode assembly according to claim 9 or 10, wherein the second electrode sheet is provided with the second recessed region, the second recessed region of the second electrode sheet being located on a side of the second electrode sheet facing the second recessed region of the first electrode sheet, the second recessed region of the second electrode sheet covering the second recessed region of the first electrode sheet facing the first electrode sheet, in a radial direction of the electrode assembly.
The electrode assembly of claim 11, wherein a width of the second recessed region of the second pole piece is greater than a width of the second recessed region of the first pole piece disposed facing the second recessed region of the second pole piece in the winding direction.
The electrode assembly according to any one of claims 1 to 12, wherein the first electrode sheet comprises a first current collector and a first active material layer coated on at least one side of the first current collector in a radial direction of the electrode assembly;

the second electrode sheet includes a second current collector and a second active material layer coated on at least one side of the second current collector in a radial direction of the electrode assembly;

wherein the first recessed region of the first pole piece includes a groove provided on the first active material layer or a region of one side of the first current collector not coated with the first active material layer;

the first concave region of the second pole piece comprises a groove arranged on the second active material layer or a region of one side of the second current collector, which is not coated with the second active material layer.
The electrode assembly of claim 13, wherein the first electrode sheet is a negative electrode sheet and the second electrode sheet is a positive electrode sheet;

the first active material layer is disposed facing the second active material layer in a radial direction of the electrode assembly, and the first active material layer covers the second active material layer.
The electrode assembly of any one of claims 1-14, wherein the electrode assembly further comprises:

The isolating film is arranged between the first pole piece and the second pole piece to separate the first pole piece from the second pole piece.
A battery cell comprising:

a housing; and

the electrode assembly of any one of claims 1-15, housed within the housing.
A battery, comprising:

a case; and

the battery cell of claim 16, the battery cell being housed within the case.
An electrical device comprising a cell according to claim 16 for providing electrical energy; or (b)

A battery comprising the battery of claim 17, the battery for providing electrical energy.