CN118140353A

CN118140353A - Electrode assembly, battery cell, battery and electricity utilization device

Info

Publication number: CN118140353A
Application number: CN202280073522.7A
Authority: CN
Inventors: 吴宇堃; 张小平; 许文竹
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2022-06-09
Filing date: 2022-08-16
Publication date: 2024-06-04
Also published as: CN217468711U; WO2023236346A1

Abstract

The application provides an electrode assembly, a battery cell, a battery and an electric device, wherein the electrode assembly is of a laminated structure, the electrode assembly comprises a plurality of first pole pieces which are laminated along a first direction, each first pole piece comprises a first coating area, a second coating area and a first tab area, the second coating area is connected with the first coating area through the first tab area, and projections of the first tab areas of the plurality of first pole pieces are overlapped along the first direction; wherein the electrode assembly satisfies one of the following conditions: a) The lengths of the first tab areas of the plurality of first pole pieces gradually decrease from one side to the other side in the first direction; b) The lengths of the first tab areas of the plurality of first pole pieces gradually decrease from two sides to the middle in the first direction. The electrode assembly of the technical scheme of the application can effectively improve the energy density while ensuring stable performance.

Description

Electrode assembly, battery cell, battery and electricity utilization device

Cross Reference to Related Applications

The present application claims priority from chinese patent application (202221426933.3) entitled "electrode assembly, battery cell, battery and electrical device," filed on month 09 of 2022, which is incorporated herein by reference in its entirety.

Technical Field

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

Background

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

In the battery technology, how to improve the energy density of the battery while ensuring the stable performance of the battery is a problem to be solved urgently.

Disclosure of Invention

The application provides an electrode assembly, a battery cell, a battery and an electric device.

In a first aspect, the present application provides an electrode assembly, the electrode assembly being of a laminated structure, the electrode assembly comprising a plurality of first electrode sheets arranged in a laminated manner along a first direction, each first electrode sheet comprising a first coating region, a second coating region and a first tab region, the second coating region and the first coating region being connected by the first tab region, projections of the first tab regions of the plurality of first electrode sheets overlapping along the first direction; wherein the electrode assembly satisfies one of the following conditions: a) The lengths of the first tab areas of the plurality of first pole pieces gradually decrease from one side to the other side in the first direction; b) The lengths of the first tab areas of the plurality of first pole pieces gradually decrease from two sides to the middle in the first direction.

The tab group of lamination formula needs to draw in adaptor or electrode terminal along its range upon range of orientation to guarantee tab group connection's stability, if the reservation length of tab group is too short, then tab group draws in the back, partial tab is easy to lead to its connection area too little because of drawing in the route length, thereby influence its stability of connecting, even there is great fracture risk, if the reservation length of tab group overlength, then can increase electrode assembly's overall weight, and tab group draws in the back, tab group's front end can form great ladder redundancy, need bigger installation space, thereby waste battery's inner space, be unfavorable for improving battery's energy density, and there is great material cost waste. According to the technical scheme, the lengths of the first tab areas are gradually reduced from one side to the other side in the first direction (namely, the stacking direction of the plurality of first tab areas), all the first tab areas are folded along the first direction from one side of the first tab area with the longest length to the other side of the first tab area with the shortest length, or the lengths of the first tab areas are gradually reduced from two sides to the middle in the first direction (namely, the stacking direction of the plurality of first tab areas), all the first tab areas are folded along the two sides of the first direction, so that the area of to-be-connected areas of all the first tab areas is sufficient after the tab groups are folded, the risk of weld joint cracking and tab fracture caused by too high pretightening force and insufficient area of to-be-connected areas of part of tabs after the tab groups are folded is reduced, and the stability of tab connection is effectively ensured, and therefore the performance stability of a battery is effectively ensured; on the other hand, the method can effectively avoid excessive step redundancy after the first tab area is folded, and effectively reduce the space occupancy rate of the first tab area while reducing the material waste and the weight of the battery, thereby effectively improving the energy density of the battery.

In addition, each first pole piece of the electrode assembly comprises a first coating area, a second coating area and a first pole lug area connected with the first coating area and the second coating area, so that a plurality of first pole pieces are laminated along a first direction to form a connected bare cell, and compared with a structure in which the electrode assembly is arranged in a split mode, the connected bare cell effectively reduces the number of connection points of the pole lugs, and therefore stability of connection of the pole lugs is further improved, and stability of battery performance is further effectively improved.

According to some embodiments of the application, the length of each first pole piece is the same; when the electrode assembly satisfies the above condition a), the electrode assembly simultaneously satisfies: the lengths of the first coating regions of the plurality of first pole pieces gradually increase from one side to the other side in the first direction, and the lengths of the second coating regions of the plurality of first pole pieces gradually increase from one side to the other side in the first direction.

In the above technical scheme, the lengths of the first pole pieces are the same, the lengths of the first coating areas and the second coating areas of the first pole pieces are gradually increased from one side to the other side in the first direction, so that the lengths of the first tab areas of the first pole pieces are gradually reduced from one side to the other side in the first direction, the lengths of the first coating areas and the second coating areas are set to be length-graded by the structure, the redundant waste of the first tab areas is reduced, the coating area of the coating areas of part of the first pole pieces is effectively increased, the total area of the coating areas of the electrode assembly is effectively increased, and the energy density of the battery is further effectively improved by increasing the total capacity of active substances.

According to some embodiments of the application, the length of each first pole piece is the same; when the electrode assembly satisfies the above condition b), the electrode assembly simultaneously satisfies: the lengths of the first coating areas of the plurality of first pole pieces gradually increase from two sides to the middle in the first direction, and the lengths of the second coating areas of the plurality of first pole pieces gradually increase from two sides to the middle in the first direction.

In the above technical scheme, the length of each first pole piece is the same, the length of the first coating area of a plurality of first pole pieces and the length of the second coating area are gradually increased from two sides to the middle in the first direction, so that the length of the first tab area of a plurality of first pole pieces is gradually reduced from two sides to the middle in the first direction, the length of the first coating area and the length of the second coating area are set to be in a length gradual change type through the structure, the redundant waste of the first tab area is reduced, the coating area of part of the first pole pieces is effectively increased, the total area of the coating area of an electrode assembly is effectively increased, and the energy density of a battery is further effectively improved by increasing the total capacity of active substances.

According to some embodiments of the application, the ratio of the length of the shortest length of the first coated region to the length of the longest length of the first coated region is greater than or equal to 0.9; and/or the ratio of the length of the second coating region with the shortest length to the length of the second coating region with the longest length is greater than or equal to 0.9.

According to the technical scheme, the length ratio of the first coating area with the shortest length to the first coating area with the longest length and the length ratio of the second coating area with the shortest length to the second coating area with the longest length are limited, so that the length difference range of the coating areas is effectively limited, the total capacity of active substances is ensured, the energy density is effectively ensured, meanwhile, after the length difference range of the coating areas is limited, the length difference range of the first tab areas is synchronously limited, the stacking thickness of the first pole pieces is limited, the situation that part of the first pole pieces are too long in the first tab areas and too short in the coating areas is avoided, and the energy density of the whole electrode assembly is effectively ensured while the tab redundancy is reduced.

According to some embodiments of the application, the ratio of the length of the first coating region to the length of the first tab region of the same first pole piece is D ₁, satisfying 1.4.ltoreq.D ₁.ltoreq.1.8; and/or the ratio of the length of the second coating area of the same first pole piece to the length of the first tab area is D ₂, which satisfies D ₂ which is more than or equal to 1.4 and less than or equal to 1.8.

In the technical scheme, the ratio of the first tab area to the total length of the first pole piece is limited by limiting the ratio of the length of the first coating area to the length of the first tab area and/or limiting the ratio of the length of the second coating area to the length of the first tab area, so that the energy density of the connected bare cell is prevented from being influenced due to overlong length of the first tab area, and meanwhile, the problems of difficult assembly and easy tearing after folding caused by overlong length of the first tab area are avoided, thereby being beneficial to effectively ensuring the energy density of the battery with stable performance.

According to some embodiments of the application, the difference in length between two adjacent first tab regions in the first direction is D3, satisfying 0.004mm < D ₃ < 0.008mm.

In the technical scheme, the difference of the lengths of the two adjacent first tab areas is more than or equal to 0.004mm and less than or equal to 0.008mm, so that the redundancy after the first tab areas are folded is further reduced while the step-shaped change of the lengths of the first tab areas is ensured.

According to some embodiments of the application, the electrode assembly further comprises a plurality of second electrode sheets, the plurality of first electrode sheets and the plurality of second electrode sheets are alternately stacked along a first direction, the first electrode sheets and the second electrode sheets are opposite in polarity, the second electrode sheets comprise a third coating region, a fourth coating region and a second electrode tab region, the third coating region and the fourth coating region are connected through the second electrode tab region, and projections of the second electrode tab regions of the plurality of second electrode sheets overlap along the first direction; wherein the electrode assembly satisfies one of the following conditions: c) The lengths of the second lug areas of the plurality of second pole pieces are gradually reduced from one side to the other side in the first direction; d) The lengths of the second lug areas of the plurality of second pole pieces are gradually reduced from two sides to the middle in the first direction.

Among the above-mentioned technical scheme, electrode assembly includes first pole piece and second pole piece, first pole piece and second pole piece can set up as electrode assembly's positive pole piece and negative pole piece respectively, the second pole piece is the same with the structure of first pole piece, the second tab district's of second pole piece length also decreases progressively or decreases progressively along first direction to the centre along one side along first direction, thereby effectively avoid second tab district to fold back part second tab district because of the pretightning force is too high, wait to connect regional area inadequately and cause the risk of welding seam fracture, tab fracture, and avoid second tab district to draw in back and produce too much redundancy, effectively improve the energy density of battery when further guaranteeing electrode assembly performance stability.

According to some embodiments of the application, the length of each second pole piece is the same; when the electrode assembly satisfies the above condition c), the electrode assembly simultaneously satisfies: the lengths of the third coating regions of the plurality of second pole pieces gradually increase from one side to the other side in the first direction, and the lengths of the fourth coating regions of the plurality of second pole pieces gradually increase from one side to the other side in the first direction.

In the above technical scheme, the lengths of the second pole piece are the same, and the lengths of the third coating area and the fourth coating area are gradually increased from one side to the other side in the first direction, so that the length of the second pole piece area is gradually reduced from one side to the other side in the first direction, the redundant waste of the second pole piece area is further reduced, the coating area of at least part of the second pole piece area is effectively increased, the total area of the coating area of the electrode assembly is effectively increased, and the energy density of the battery is further effectively improved by increasing the total capacity of active substances.

According to some embodiments of the application, the length of each second pole piece is the same; when the electrode assembly satisfies the above condition d), the electrode assembly simultaneously satisfies: the lengths of the third coating areas of the second pole pieces gradually increase from two sides to the middle in the first direction, and the lengths of the fourth coating areas of the second pole pieces gradually increase from two sides to the middle in the first direction.

In the above technical scheme, the lengths of the second pole piece are the same, and the lengths of the third coating area and the fourth coating area are gradually increased from two sides to the middle in the first direction, so that the length of the second pole piece area is gradually reduced from two sides to the middle in the first direction, the redundant waste of the second pole piece area is further reduced, the coating area of at least part of the second pole piece area is effectively increased, the total area of the coating area of the electrode assembly is effectively increased, and the energy density of the battery is further effectively improved by increasing the total capacity of active substances.

In a second aspect, the present application provides a battery cell comprising: the electrode assembly according to any one of the above aspects, the first tab region being bent such that a projection of the first coating region in a thickness direction thereof overlaps a projection of the second coating region in a thickness direction thereof; a case assembly in which the electrode assembly is housed, the case assembly including a first electrode lead-out portion; the first transfer piece is electrically connected with the first tab areas of the plurality of first pole pieces and the first electrode lead-out parts.

In the above technical scheme, the first tab region is bent, so that the thickness directions of the first coating region and the second coating region are consistent, the first tab region is positioned on the same side of the first coating region and the second coating region, the electrode assembly is accommodated in the shell assembly, and the first transfer piece is connected with the first tab region and the first electrode leading-out part to form a battery cell. The battery cell according to the second aspect of the present application also has better performance stability and higher energy density due to the characteristics of the electrode assembly according to the first aspect of the present application.

According to some embodiments of the application, the first adapter comprises a body, a first arm and a second arm, the body is connected to the first electrode lead-out portion, the first arm and the second arm extend from one end of the body, a gap is formed between the first arm and the second arm, and the first tab areas of the plurality of first pole pieces are inserted into the gap and connected to the first arm and the second arm.

In the above technical scheme, first adapter includes body and the first arm and the second arm that extend from the same end of body, have between first arm and the second arm and supply first utmost point ear district male clearance, like this, after first adapter and the first electrode portion of drawing forth of first utmost point ear district through this kind of structure are connected, first arm and the second arm of first adapter play fastening and spacing effect to first utmost point ear district, reduce the risk that first utmost point ear district collapses to first coating district and second coating district to reduce the risk that causes battery monomer short circuit because of first utmost point ear district warp, further effectively improve battery monomer's performance stability.

In a third aspect, the application also provides a battery comprising a battery cell according to any of the above aspects.

The battery according to the embodiment of the third aspect of the present application also has better performance stability and higher energy density due to the characteristics of the battery cell according to the embodiment of the second aspect of the present application.

In a fourth aspect, the application also provides an electric device, which comprises the battery according to the scheme, wherein the battery is used for providing electric 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 as limiting the scope, and 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 provided in some embodiments of the present application;

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

fig. 4 is a front view of an electrode assembly provided in some embodiments of the application;

FIG. 5 is a cross-sectional view of the first tab region of the first embodiment in the direction A-A shown in FIG. 4 in an undeployed state;

FIG. 6 is a cross-sectional view of the first tab area of the first embodiment shown in FIG. 5 in a collapsed condition;

FIG. 7 is a cross-sectional view of the first tab area of the second embodiment in the direction A-A shown in FIG. 4 in an undeployed state;

FIG. 8 is a cross-sectional view of the second embodiment of FIG. 7 in a collapsed state of the first tab area;

fig. 9 is a front view of an electrode assembly provided in further embodiments of the present application;

FIG. 10 is a cross-sectional view of the first tab region of the first embodiment in the B-B direction shown in FIG. 9 in an undeployed state;

FIG. 11 is a cross-sectional view of the first tab area of the first embodiment shown in FIG. 10 in a collapsed condition;

FIG. 12 is a cross-sectional view of the second embodiment of the B-B direction shown in FIG. 9 in a non-collapsed state of the first tab region;

FIG. 13 is a cross-sectional view of the second embodiment of FIG. 12 in a collapsed state of the first tab area;

Fig. 14 is a front cross-sectional view of a battery cell according to some embodiments of the present application;

fig. 15 is an enlarged schematic view of a partial structure of a portion C shown in fig. 14;

FIG. 16 is a front view of a first adapter provided in some embodiments of the present application;

FIG. 17 is a bottom view of a first adapter provided in some embodiments of the present application;

fig. 18 is a bottom view of a first adapter provided in accordance with still further embodiments of the present application.

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

Marking: 1000-vehicle; 100-cell; 10-battery cell; 11-a housing assembly; 111-a housing; 112-end caps; 113-a first electrode lead-out portion; 12-an electrode assembly; 121-a first pole piece; 1211-a first coating zone; 1212-a first tab region; 1213-a second coating zone; 122-a second pole piece; 1221-a third coating zone; 1222-a second ear region; 1223-fourth coating zone; 13-a first adapter; 131-body; 132-a first arm; 133-a second arm; 134-gap; 20-a box body; 21-a first part; 22-a second part; l ₁ -length of the first pole piece; l ₁₁ -length of the first tab region; l ₁₂ -length of the first coating zone; l ₁₃ -length of the second coating zone; l ₂ -the length of the second pole piece; l ₂₁ -the length of the second ear region; l ₂₂ -the length of the third coating zone; l ₂₃ -length of the fourth coating zone; 200-a controller; 300-motor.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying 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 of the present application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit 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 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 of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.

In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein 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. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In describing embodiments of the present application, the term "plurality" refers to more than two (including two).

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; the device can be mechanically connected, electrically connected and signal connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to specific circumstances.

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

Reference to a battery in accordance with an embodiment of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. The battery cells can be directly formed by series connection, parallel connection or series-parallel connection, and the series-parallel connection refers to that the battery cells are connected in series or in parallel. The battery modules can be formed by connecting a plurality of battery monomers in series, parallel or series-parallel connection, and then the battery modules are connected in series, parallel or series-parallel connection to form a battery. The battery may also include a case for enclosing one or more battery cells. The case body can prevent liquid or other foreign matters from affecting the charge or discharge of the battery cells.

The battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiment of the application. The battery cell may be in a cylindrical shape, a flat shape, a rectangular parallelepiped shape, or other shapes, which is not limited in this embodiment of the application. 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 package battery cell are not limited in this embodiment.

The battery cell comprises an electrode assembly and electrolyte, wherein 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, the positive electrode current collector without the positive electrode active material layer protrudes out of the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer is used as a 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, the negative electrode current collector without the negative electrode active material layer protrudes out of the negative electrode current collector coated with the negative electrode active material layer, and the negative electrode current collector without the negative electrode active material layer is used as a 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 material of the separator may be PP (polypropylene) or PE (polyethylene). In addition, the electrode assembly may be a roll-to-roll structure or a lamination structure, and embodiments of the present application are not limited thereto.

Currently, the application of power batteries is more widespread from the development of market situation. The power battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and the like, and a plurality of fields such as military equipment, aerospace, and the like. With the continuous expansion of the application field of the power battery, the market demand of the power battery is also continuously expanding.

The applicant analyses and notices that when the electrode assembly with the tab-shaped tab group is assembled, the tab group needs to be folded along the stacking direction and then connected to the adapter or the electrode terminal, so that each tab of the tab group can be connected stably.

In order to ensure the connection stability of all the lugs of the lug group, the applicant lengthens the reserved length of the lug group in advance so as to ensure that the lugs furthest from the gathering area can be stably gathered and connected, but after the mode is adopted, most of the lugs of the lug group are redundant in the length direction, and after the lugs are gathered, the front end of the lug group is formed into larger step redundancy, so that the space occupation rate of the lug group with the structure is large, and larger installation space is required to be reserved, thereby wasting the internal space of a battery and being unfavorable for improving the energy density of the battery; and after the batteries are grouped, the redundant parts of the tabs are easily inserted into the main body part of the electrode assembly to cause short circuit of the batteries, thereby further affecting the performance stability of the batteries.

In order to improve the performance stability of the battery cell and effectively improve the energy density, the applicant designs an electrode assembly which is of a laminated structure, wherein the electrode assembly comprises a plurality of first pole pieces which are laminated along a first direction, each first pole piece comprises a first coating area, a second coating area and a first tab area, the second coating areas are connected with the first coating areas through the first tab areas, the first tab areas of the plurality of first pole pieces are laminated along the first direction, and the lengths of the first tab areas of the plurality of first pole pieces are gradually reduced from one side to the other side in the first direction; or, the lengths of the first tab regions of the plurality of first pole pieces gradually decrease from two sides to the middle in the first direction.

It can be understood that in the structure that the lengths of the first tab regions of the plurality of first pole pieces gradually decrease from one side to the other side in the first direction, the plurality of first tab regions are gathered from one side to the other side in the first direction; in the structure that the lengths of the first tab regions of the plurality of first pole pieces gradually decrease from two sides to the middle in the first direction, the plurality of first tab regions are folded from two sides to the middle in the first direction.

The electrode assembly with the structure ensures that after the electrode lug group is folded, the lengths of all the first electrode lug areas meet the folding requirement, the area of a to-be-connected area formed after the folding of all the first electrode lug areas is sufficient, the risks of weld joint cracking and electrode lug fracture caused by too high pretightening force and insufficient area of the to-be-connected area of part of the first electrode lug areas after the folding are reduced, the stability of electrode lug connection is effectively ensured, and meanwhile, the problem of battery cell short circuit caused by the fact that the redundant part of the first electrode lug areas is inserted into the main body of the electrode assembly is avoided, so that the performance stability of the electrode assembly is effectively improved; in addition, the structure of the application effectively avoids excessive step redundancy after the first tab area is folded, so that the space occupancy rate of the first tab area can be effectively reduced, thereby being beneficial to effectively improving the energy density of the battery.

The battery cell disclosed by the embodiment of the application can be used in electric devices such as vehicles, ships or aircrafts, but is not limited to the electric devices. A power supply system having the battery cell, the battery, and the like disclosed in the present application constituting the power utilization device may be used.

The embodiment of the application provides an electric device using a battery as a power supply, wherein the electric 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.

The battery described in the embodiments of the present application is not limited to the above-described power consumption device, but may be applied to all power consumption devices using batteries, but for simplicity of description, the following embodiment will take a power consumption device according to an embodiment of the present application as an example of a vehicle.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the 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 other embodiments, 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 20 and a battery cell 10, and the battery cell 10 is accommodated in the case 20. The case 20 is used to provide an accommodating space for the battery cell 10, and the case 20 may have various structures. In some embodiments, the case 20 may include a first portion 21 and a second portion 22, the first portion 21 and the second portion 22 being overlapped with each other, the first portion 21 and the second portion 22 together defining an accommodating space for accommodating the battery cell 10. The second portion 22 may be a hollow structure with one end opened, the first portion 21 may be a plate-shaped structure, and the first portion 21 covers the opening side of the second portion 22, so that the first portion 21 and the second portion 22 together define an accommodating space; the first portion 21 and the second portion 22 may be hollow structures each having an opening at one side, and the opening side of the first portion 21 is engaged with the opening side of the second portion 22. Of course, the case 20 formed by the first portion 21 and the second portion 22 may have various shapes, such as a rectangular parallelepiped, a square, and the like.

In the battery 100, the number of the battery cells 10 may be plural, and the plural battery cells 10 may be connected in series, parallel, or series-parallel, and series-parallel refers to both of the plural battery cells 10 being connected in series and parallel. The plurality of battery cells 10 can be directly connected in series or in parallel or in series-parallel, however, the battery 100 can also be a battery module form formed by connecting the plurality of battery cells 10 in series or in parallel or in series-parallel, and then connecting the plurality of battery modules in series or in parallel or in series-parallel to form a whole.

Each of the battery cells 10 may be a secondary battery or a primary battery, or may be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

Referring to fig. 3, fig. 3 is an exploded view of a battery cell according to some embodiments of the present application. The battery cell 10 may include a case assembly 11, an electrode assembly 12, and an adapter, the case assembly 11 may include a case 111 and an end cap 112, the case 111 having an opening, the end cap 112 covering the opening of the case 111 and forming a sealed connection to form a sealed space for accommodating the electrode assembly 12 and electrolyte.

In assembling the battery cell 10, the electrode assembly 12 may be first placed in the case 111, the case 111 may be filled with electrolyte, and then the end cap 112 may be covered on the opening of the case 111.

The case 111 may be in various shapes, and the shape of the case 111 may be determined according to the specific shape of the electrode assembly 12. For example, if the electrode assembly 12 has a rectangular parallelepiped structure, a rectangular parallelepiped case 111 may be used. Of course, the end cap 112 may be of various configurations.

It is understood that the case assembly 11 is not limited to the above-described structure, and for example, the case assembly 11 may include a case 111 and two end caps 112, the case 111 being a hollow structure having opposite side openings, and one end cap 112 being correspondingly covered at one opening of the case 111 and forming a sealing connection to form a sealed space for accommodating the electrode assembly 12 and the electrolyte.

The housing assembly 11 further includes an electric energy extraction portion, which may be disposed on the end cap 112 in an insulating manner, and the electric energy extraction portion is configured to output current of the electrode assembly 12, and the electric energy extraction portion may be directly connected to the electrode assembly 12 or may be connected through an adapter.

The adapter plays a role in overcurrent and confluence, and the power extraction part is electrically connected with the tab of the electrode assembly 12 through the connector.

The electrode assembly 12 is a component in which electrochemical reactions occur in the battery cell 10. The electrode assembly 12 may include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 12 may be a wound structure formed by winding a positive electrode sheet, a separator, and a negative electrode sheet, or may be a laminated structure formed by laminating a positive electrode sheet, a separator, and a negative electrode sheet.

Referring to fig. 4 to 8, fig. 4 is a front view of an electrode assembly according to some embodiments of the present application; FIG. 5 is a cross-sectional view of the first tab region of the first embodiment in the direction A-A shown in FIG. 4 in an undeployed state; FIG. 6 is a cross-sectional view of the first tab area of the first embodiment shown in FIG. 5 in a collapsed condition; FIG. 7 is a cross-sectional view of the first tab area of the second embodiment in the direction A-A shown in FIG. 4 in an undeployed state; fig. 8 is a cross-sectional view of the second embodiment of fig. 7 in a collapsed state of the first tab region. Some embodiments of the present application provide an electrode assembly 12, the electrode assembly 12 being a laminated structure, the electrode assembly 12 including a plurality of first electrode sheets 121 laminated along a first direction, each first electrode sheet 121 including a first coating region 1211, a second coating region 1213, and a first tab region 1212, the second coating region 1213 and the first coating region 1211 being connected by the first tab region 1212, projections of the first tab regions 1212 of the plurality of first electrode sheets 121 overlapping along the first direction; wherein the electrode assembly 12 satisfies one of the following conditions: a) The lengths L ₁₁ of the first tab areas of the plurality of first pole pieces 121 gradually decrease from one side to the other side in the first direction; b) The lengths L ₁₁ of the first tab regions of the plurality of first pole pieces 121 gradually decrease from both sides in the first direction to the middle.

The first electrode tab 121 includes a current collector and an active material layer coated on the current collector, a region coated with the active material layer on the current collector forms a first coating region 1211 and a second coating region 1213, and a blank region uncoated with the active material layer on the current collector forms a first tab region 1212. The first electrode sheet 121 may be a positive electrode sheet or a negative electrode sheet, that is, the coating layers of the first and second coating regions 1211 and 1213 may be the same positive electrode active material layer or the same negative electrode active material layer, and of course, the current collector and the active material have the same polarity.

Each of the first electrode sheets 121 includes a first coating region 1211, a second coating region 1213, and a first tab region 1212 connecting the first and second coating regions 1211 and 1213, and after a plurality of first electrode sheets 121 are stacked in a first direction, a one-piece electrode assembly including two body portions and one tab region may be formed.

As shown in fig. 5, the first direction may extend along the X direction in the drawing, and the projections of the first tab regions 1212 of the plurality of first pole pieces 121 overlap along the first direction X.

As shown in fig. 4 and 5, the first coating region 1211, the first tab region 1212, and the second coating region 1213 are arranged along the second direction Y, the second direction Y is perpendicular to the first direction X, the length L ₁₁ of the first tab region is the dimension of the first tab region 1212 in the second direction Y, the length L ₁₂ of the first coating region is the dimension of the first coating region 1211 in the second direction Y, and the length L ₁₃ of the second coating region is the length of the second coating region 1213 in the second direction Y.

The lengths L ₁₁ of the first tab regions of the plurality of first pole pieces 121 may be gradually reduced from one side to the other side in the first direction, or may be gradually reduced from two sides to the middle in the first direction, where the lengths L ₁₂ of the first coating regions of the plurality of first pole pieces 121 may be equal or different, and similarly, the lengths L ₁₃ of the plurality of second coating regions may be equal or different.

The length L ₁₁ of the first tab area is gradually decreased from one side to the other side in the first direction X (namely, the stacking direction of a plurality of first tab areas 1212), all the first tab areas 1212 are folded along the first direction from one side where the first tab area 1212 with the longest length is located to the other side where the first tab area 1212 with the shortest length is located, or the length L ₁₁ of the first tab area is gradually decreased from the two sides to the middle of the first direction X, all the first tab areas 1212 are folded along the two sides to the middle of the first direction, on one hand, after the tab group is folded, the area of the to-be-connected area of all the first tab areas 1212 is sufficient, the risk of weld joint cracking and tab fracture caused by the fact that the pretightening force is too high after the tab is folded and the area of the to-be-connected area is insufficient is reduced, and the stability of tab connection is effectively ensured, so that the performance stability of the battery 100 is effectively ensured; on the other hand, the method can effectively avoid excessive step redundancy after the first tab region 1212 is folded, and effectively reduce the space occupation rate of the first tab region 1212 while reducing the material waste and the weight of the battery 100, thereby effectively improving the energy density of the battery 100.

In addition, each first electrode tab 121 of the electrode assembly 12 of the present application includes a first coating region 1211 and a second coating region 1213, and a first tab region 1212 connecting the first coating region 1211 and the second coating region 1213, so that a plurality of first electrode tabs 121 are stacked along a first direction X to form a conjoined bare cell, and compared with a structure in which the electrode assembly 12 is separately arranged, the conjoined bare cell effectively reduces the number of connection points of the tabs, thereby further improving the stability of tab connection, and further effectively improving the stability of the performance of the battery 100.

According to some embodiments of the application, the length L ₁ of each first pole piece is the same; when the electrode assembly 12 satisfies the above condition a), the electrode assembly 12 simultaneously satisfies: the length L ₁₂ of the first coating region of the plurality of first pole pieces 121 gradually increases from one side to the other side in the first direction, and the length L ₁₃ of the second coating region of the plurality of first pole pieces 121 gradually increases from one side to the other side in the first direction.

The length L ₁ of each first pole piece is the same, meaning that the length of each pole piece in the second direction Y is the same, i.e., the total length of the first coated region 1211, the first tab region 1212, and the second coated region 1213 of each first pole piece 121 in the second direction Y is the same.

For ease of understanding, defining the first direction as two sides, a first side and a second side, the length L ₁₂ of the first coating region of the plurality of first pole pieces 121 gradually increases from one side to the other side in the first direction, and the length L ₁₃ of the second coating region of the plurality of first pole pieces 121 gradually increases from one side to the other side in the first direction means that the length L ₁₂ of the first coating region of the plurality of first pole pieces 121 gradually increases from the first side to the second side in the first direction, and at the same time, the length L ₁₃ of the second coating region of the plurality of first pole pieces 121 gradually increases from the first side to the second side in the first direction.

It will be appreciated that the length of each first pole piece 121 in the second direction Y is the same, and the lengths L ₁₂ and L ₁₃ of the first and second coating regions of the plurality of first pole pieces 121 are each gradually increased from the first side to the second side in the first direction, so that the length L11 of the first tab region of the plurality of first pole pieces 121 is gradually decreased from the first side to the second side in the first direction. The first tab regions 1212 of the plurality of first pole pieces 121 are folded from the first side to the second side along the first direction X, so as to fold the plurality of first tab regions 1212 at the side where the first tab region 1212 with the shortest length is located.

Wherein, two ends of the plurality of first pole pieces 121 along the second direction Y are substantially aligned in the first direction X, so as to maximize an overlapping area of projections of the plurality of first tab regions 1212 in the first direction X.

The length L ₁ of each first electrode tab is identical, the length L ₁₂ of the first coating region and the length L ₁₃ of the second coating region of the plurality of first electrode tabs 121 are gradually increased from one side to the other side in the first direction, so that the length L ₁₁ of the first tab region of the plurality of first electrode tabs 121 is gradually decreased from one side to the other side in the first direction, and the structure sets the lengths L ₁₃ of the first coating region 1211 and the second coating region to be a length-gradual type, effectively increases the coating area of the coating region of a portion of the first electrode tabs 121 while reducing the redundancy waste of the first tab region 1212, thereby effectively increasing the total area of the coating region of the electrode assembly 12, and further effectively improving the energy density of the battery 100 by increasing the total capacity of active materials.

According to some embodiments of the application, the length L ₁ of each first pole piece is the same; when the electrode assembly 12 satisfies the above condition b), the electrode assembly 12 simultaneously satisfies: the lengths L ₁₂ of the first coating regions of the plurality of first pole pieces 121 gradually increase from both sides in the first direction to the middle, and the lengths L ₁₃ of the second coating regions of the plurality of first pole pieces 121 gradually increase from both sides in the first direction to the middle.

As described above, the length L ₁ of each first pole piece is the same, meaning that the length of each pole piece in the second direction Y is the same, i.e., the total length of the first coated region 1211, the first tab region 1212, and the second coated region 1213 of each first pole piece 121 in the second direction Y is the same.

It will be appreciated that the length of each first pole piece 121 in the second direction Y is the same, and the lengths L ₁₂ and L ₁₃ of the first and second coating regions of the plurality of first pole pieces 121 gradually increase from two sides to the middle in the first direction, so that the length L ₁₁ of the first tab region of the plurality of first pole pieces 121 gradually decreases from two sides to the middle in the first direction. The first tab regions 1212 of the plurality of first pole pieces 121 are folded from two sides to the middle along the first direction X, so as to fold the plurality of first tab regions 1212 at a middle position in the first direction X where the first tab region 1212 with the shortest length is located.

The two ends of the plurality of first pole pieces 121 along the second direction Y are approximately aligned in the first direction X, so that the overlapping area of the projections of the plurality of first pole lugs in the first direction X is maximized, a larger overlapping area is ensured after the plurality of first pole lug areas 1212 are folded, and an area to be connected is formed in the overlapping area, so that the first pole lug areas 1212 are conveniently connected with the adapter or directly connected with the electric energy extraction part.

The length L ₁ of each first pole piece is the same, the length L ₁₂ of the first coating region and the length L ₁₃ of the second coating region of the plurality of first pole pieces 121 are gradually increased from two sides to the middle in the first direction, so that the length L ₁₁ of the first tab region of the plurality of first pole pieces 121 is gradually reduced from two sides to the middle in the first direction, and the length L ₁₃ of the first coating region 1211 and the length L ₁₃ of the second coating region are set to be of a length-gradual type by such a structure, the redundancy waste of the first tab region 1212 is reduced while the coating area of a part of the coating region of the first pole pieces 121 is effectively increased, thereby effectively increasing the total area of the coating region of the electrode assembly 12, and further effectively increasing the energy density of the battery 100 by increasing the total capacity of active materials.

According to some embodiments of the application, the ratio of the length L ₁₂ of the shortest length first coating zone to the length L ₁₂ of the longest first coating zone is greater than or equal to 0.9; and/or the ratio of the length L ₁₃ of the shortest second coating zone 1213 to the length L ₁₃ of the longest second coating zone is 0.9 or more.

The first coating region 1211 having the shortest length refers to the first coating region 1211 having the shortest length in the second direction Y of all the first electrode sheets 121, the first coating region 1211 having the longest length refers to the first coating region 1211 having the longest length in the second direction Y of all the first electrode sheets 121, the second coating region 1213 having the shortest length refers to the second coating region 1213 having the shortest length in the second direction Y of all the first electrode sheets 121, and the second coating region 1213 having the longest length refers to the second coating region 1213 having the longest length in the second direction Y of all the first electrode sheets 121.

The ratio of the length L ₁₂ of the shortest first coating region to the length L ₁₂ of the longest first coating region may be 0.9,0.91,0.92 or the like any value of 0.9 or more and less than 1. Similarly, the ratio of the length L ₁₃ of the second coating region having the shortest length to the length L ₁₃ of the second coating region having the longest length is 0.9 or more and less than 1, that is, the ratio of the length L ₁₃ of the second coating region having the shortest length to the length L ₁₃ of the second coating region having the longest length may be 0.9,0.91,0.92 or the like, which is any value of 0.9 or more and less than 1.

The ratio of the length L ₁₂ of the first coating region with the shortest length to the length L ₁₂ of the first coating region with the longest length and the ratio of the length L ₁₃ of the second coating region with the shortest length to the length L ₁₃ of the second coating region with the longest length are limited so as to effectively limit the length difference range of the coating regions, thereby ensuring the total capacity of active substances and effectively ensuring the energy density, and meanwhile, after the length difference range of the coating regions is limited, the length difference range of the first tab regions is synchronously limited so as to limit the stacking thickness of the first pole piece 121, thereby avoiding the conditions that part of the first pole piece 121 is too long in the first tab region 1212 and too short in the coating region, and effectively ensuring the energy density of the whole electrode assembly 12 while reducing the tab redundancy.

According to some embodiments of the present application, the ratio of the length L ₁₂ of the first coating region and the length L ₁₁ of the first tab region of the same first pole piece 121 is D ₁, satisfying 1.4.ltoreq.D ₁.ltoreq.1.8; and/or the ratio of the length L ₁₃ of the second coating region of the same first pole piece 121 to the length L ₁₁ of the first tab region is D ₂, which satisfies 1.4-D ₂ -1.8.

Specifically, the ratio of the length of the first coating region 1211 of the same first pole piece 121 in the second direction Y to the length of the first tab region 1212 in the second direction Y is D ₁, and the ratio of the length of the second coating region 1213 of the same first pole piece 121 in the second direction Y to the length of the first tab region 1212 in the second direction Y is D ₂.

The ratio of the length of the first coating region 1211 of the same first electrode tab 121 in the second direction Y to the length of the first tab region 1212 in the second direction Y may be any value of 1.4 or more and 1.8 or less, such as 1.4, 1.5, 1.8 or more. Similarly, the ratio of the length of the second coating region 1213 of the same first electrode tab 121 in the second direction Y to the length of the first tab region 1212 in the second direction Y may be any value of 1.4 or more and 1.8 or less, such as 1.4, 1.5, 1.8 or more.

The ratio of the first tab region 1212 to the total length of the first pole piece 121 is defined by defining the ratio of the length L ₁₁ of the first coating region 1211 to the length L ₁₁ of the first tab region and/or defining the ratio of the length L ₁₁ of the second coating region 1213 to the length L ₁₁ of the first tab region, so that the energy density of the conjoined bare cell is prevented from being influenced due to the overlong length of the first tab region 1212, and the problems of difficult assembly and easy tearing after folding caused by the overlong length of the first tab region 1212 are avoided, thereby being beneficial to ensuring the energy density while ensuring the stable performance.

According to some embodiments of the present application, the difference in the lengths of two adjacent first tab regions 1212 in the first direction Y is D ₃, satisfying 0.004mm ∈d ₃ ∈0.008mm.

Specifically, along the first direction X, the difference D ₃ between the lengths of two adjacent first tab regions is 0.004mm or more and 0.008mm or less. It can be understood that the lengths L ₁₁ of the plurality of first tab regions may be equally reduced, that is, the lengths of any two adjacent first tab regions are equal, and the length difference may be any value greater than or equal to 0.004mm and less than or equal to 0.008 mm; of course, the lengths L ₁₁ of the plurality of first tab regions may also decrease in a non-equal manner, that is, the difference between the lengths of any two adjacent first tab regions may be the same or different, and the difference between the lengths is any value greater than or equal to 0.004mm and less than or equal to 0.008mm.

The difference of the lengths of the two adjacent first tab areas is more than or equal to 0.004mm and less than or equal to 0.008mm, and the redundancy after the first tab areas 1212 are folded is further reduced while the step-like change of the length L ₁₁ of the first tab areas is ensured.

Referring to fig. 9 to 13, fig. 9 is a front view of an electrode assembly according to still other embodiments of the present application; FIG. 10 is a cross-sectional view of the first tab region of the first embodiment in the B-B direction shown in FIG. 9 in an undeployed state; FIG. 11 is a cross-sectional view of the first tab area of the first embodiment shown in FIG. 10 in a collapsed condition; FIG. 12 is a cross-sectional view of the second embodiment of the B-B direction shown in FIG. 9 in a non-collapsed state of the first tab region; fig. 13 is a cross-sectional view of the second embodiment of fig. 12 in a collapsed state of the first tab region. The electrode assembly 12 further includes a plurality of second electrode sheets 122, the plurality of first electrode sheets 121 and the plurality of second electrode sheets 122 are alternately stacked in the first direction, the first electrode sheets 121 and the second electrode sheets 122 are opposite in polarity, the second electrode sheets 122 include a third coating area 1221, a fourth coating area 1223 and a second tab area 1222, the third coating area 1221 and the fourth coating area 1223 are connected by the second tab area 1222, and projections of the second tab areas 1222 of the plurality of second electrode sheets 122 overlap in the first direction; wherein the electrode assembly 12 satisfies one of the following conditions: c) The lengths L ₂₁ of the second tab regions of the plurality of second pole pieces 122 each gradually decrease from one side to the other side in the first direction; d) The lengths L ₂₁ of the second tab regions of the plurality of second pole pieces 122 each gradually decrease from two sides in the first direction to the middle.

As described above, the first electrode sheet 121 may be a positive electrode sheet or a negative electrode sheet, and when the first electrode sheet 121 is a positive electrode sheet, the second electrode sheet 122 may be a negative electrode sheet, and when the first electrode sheet 121 is a negative electrode sheet, the second electrode sheet 122 may be a positive electrode sheet, and the first electrode sheet 121 and the second electrode sheet 122 are alternately stacked in the first direction to form the laminated electrode assembly 12.

The first direction may extend along the X direction in the figure, and the projections of the second tab regions 1222 of the plurality of second pole pieces 122 overlap along the first direction X.

The third coating area 1221, the second ear area 1222, and the fourth coating area 1223 are arranged along the second direction Y, which is perpendicular to the first direction X, the length L ₂₁ of the second ear area is the dimension of the second ear area 1222 in the second direction Y, the length L ₂₂ of the third coating area is the dimension of the third coating area 1221 in the second direction Y, and the length L ₂₃ of the fourth coating area is the length of the fourth coating area 1223 in the second direction Y.

The lengths L ₂₁ of the second tab regions of the plurality of second pole pieces 122 may be gradually reduced from one side to the other side in the first direction, or may be gradually reduced from two sides to the middle in the first direction, where the lengths L ₂₂ of the third coating regions of the plurality of second pole pieces 122 may be equal or may be unequal, and similarly, the lengths L ₂₃ of the plurality of fourth coating regions may be equal or may be unequal.

It is understood that the first tab regions 1212 of the first pole pieces 121 and the second tab regions 1222 of the second pole pieces 122 should be spaced apart to avoid short-circuiting caused by contact between the first tab regions 1212 and the second tab regions 1222 having different polarities. As shown in fig. 9, the first tab region 1212 and the second tab region 1222 are spaced apart along a third direction Z, wherein the third direction Z is perpendicular to the first direction X and the second direction Y.

The electrode assembly 12 comprises a first electrode plate 121 and a second electrode plate 122, the first electrode plate 121 and the second electrode plate 122 can be respectively arranged as an anode electrode plate and a cathode electrode plate of the electrode assembly 12, the second electrode plate 122 is similar to the first electrode plate 121 in structure, namely, the length L ₂₁ of a second electrode lug area of the second electrode plate 122 is gradually decreased to one side along a first direction or gradually decreased to the middle along the first direction, so that the risk of weld joint cracking and electrode lug fracture caused by too high pretightening force and insufficient area of an area to be connected of the second electrode lug area 1222 after the second electrode lug area 1222 is folded is effectively avoided, excessive redundancy is avoided after the second electrode lug area 1222 is folded, and the energy density of the battery 100 is effectively improved while the performance stability of the electrode assembly 12 is further ensured.

According to some embodiments of the application, the length L ₂ of each second pole piece is the same; when the above condition c) is satisfied by the electrode assembly 12, the electrode assembly 12 simultaneously satisfies: the length L ₂₂ of the third coating region of the plurality of second pole pieces 122 gradually increases from one side to the other side in the first direction, and the length _L23 of the fourth coating region of the plurality of second pole pieces 122 gradually increases from one side to the other side in the first direction.

The length L ₂ of each second pole piece is the same, meaning that the length of each pole piece in the second direction Y is the same, i.e., the total length of the third coated region 1221, the second tab region 1222, and the fourth coated region 1223 of each second pole piece 122 in the second direction Y is the same.

For ease of understanding, defining the first direction as two sides, a first side and a second side, the length L ₂₂ of the third coating region of the plurality of second pole pieces 122 gradually increases from one side to the other side in the first direction, and the length L ₂₃ of the fourth coating region of the plurality of second pole pieces 122 gradually increases from one side to the other side in the first direction means that the length L ₂₂ of the third coating region of the plurality of second pole pieces 122 gradually increases from the first side to the second side in the first direction, and at the same time, the length L ₂₃ of the fourth coating region of the plurality of second pole pieces 122 gradually increases from the first side to the second side in the first direction.

It will be appreciated that the length of each second pole piece 122 in the second direction Y is the same, and the lengths L ₂₂ and L ₂₃ of the third and fourth coating regions of the plurality of second pole pieces 122 each gradually increase from the first side to the second side in the first direction X, and the lengths of the fourth tab regions of the plurality of second pole pieces 122 correspondingly gradually decrease from the first side to the second side in the first direction. The second tab regions 1222 of the plurality of second pole pieces 122 are folded from the first side to the second side along the first direction X to fold the plurality of second tab regions 1222 on a side of the shortest length of the second tab regions 1222.

Wherein both ends of the plurality of second pole pieces 122 in the second direction Y are substantially aligned in the first direction X to maximize an overlapping area of projections of the plurality of second pole ear regions 1222 in the first direction X.

The lengths L ₂ of the second pole piece are the same, and the lengths L ₂₃ of the third and fourth coating regions 1221 and ₂₃ are each gradually increased from one side to the other side in the first direction, so that the length L ₂₁ of the second tab region is gradually decreased from one side to the other side in the first direction, thereby effectively increasing the coating area of the coating region of at least part of the second pole piece 122 while further reducing the redundancy waste of the second tab region 1222, thereby effectively increasing the total area of the coating region of the electrode assembly 12, and further effectively increasing the energy density of the battery 100 by increasing the total capacity of the active material.

According to some embodiments of the application, the length L ₂ of each second pole piece is the same; when the electrode assembly 12 satisfies the above condition d), the electrode assembly 12 simultaneously satisfies: the length L ₂₂ of the third coating region of the plurality of second pole pieces 122 gradually increases from both sides in the first direction to the middle, and the length L ₂₃ of the fourth coating region of the plurality of second pole pieces 122 gradually increases from both sides in the first direction to the middle.

As described above, the length L ₂ of each second pole piece is the same, meaning that the length of each pole piece in the second direction Y is the same, i.e., the total length of the third coated region 1221, the second tab region 1222, and the fourth coated region 1223 of each second pole piece 122 in the second direction Y is the same.

It will be appreciated that the length of each second pole piece 122 in the second direction Y is the same, and the lengths L ₂₂ and L ₂₃ of the third and fourth coating regions of the plurality of second pole pieces 122 each gradually increase from two sides in the first direction to the middle, and then the lengths L ₂₁ of the second tab regions of the plurality of second pole pieces 122 gradually decrease from two sides in the first direction to the middle. The second tab regions 1222 of the plurality of second pole pieces 122 are folded from two sides to the middle along the first direction X to fold the plurality of second tab regions 1222 at a middle position in the first direction X where the second tab region 1222 having the shortest length is located.

The two ends of the plurality of second pole pieces 122 along the second direction Y are approximately aligned in the first direction X, so as to maximize the overlapping area of the projections of the plurality of second pole pieces on the first direction X, ensure that the plurality of second pole piece areas 1222 can have a larger overlapping area after being folded, and form an area to be connected in the overlapping area, so that the first pole piece area 1212 is conveniently connected with the adapter or directly connected with the electric energy extraction part.

The lengths of the second pole piece L ₂ are the same, and the lengths of the third coating region 1221 and the fourth coating region are each gradually increased from both sides in the first direction to the middle, so that the length L ₂₁ of the second pole piece region is gradually decreased from both sides in the first direction to the middle, thereby effectively increasing the coating area of the coating region of at least part of the second pole piece 122 while further reducing the redundancy waste of the second pole piece region 1222, thereby effectively increasing the total area of the coating region of the electrode assembly 12, and further effectively increasing the energy density of the battery 100 by increasing the total capacity of the active material.

Referring to fig. 4 to 8, some embodiments of the present application provide an electrode assembly 12, wherein the electrode assembly 12 is a laminated structure, the electrode assembly 12 includes a plurality of first electrode sheets 121 stacked along a first direction, each first electrode sheet 121 includes a first coating region 1211, a second coating region 1213 and a first tab region 1212, the second coating region 1213 and the first coating region 1211 are connected by the first tab region 1212, and projections of the first tab regions 1212 of the plurality of first electrode sheets 121 overlap along the first direction; the length L ₁ of each first pole piece is the same, the length L ₁₂ of the first coating regions of the plurality of first pole pieces 121 gradually increases from one side to the other side in the first direction, the length L ₁₃ of the second coating regions of the plurality of first pole pieces 121 gradually increases from one side to the other side in the first direction, and the length L ₁₁ of the first tab regions of the plurality of first pole pieces 121 gradually decreases from one side to the other side in the first direction.

Referring to fig. 4 to 8, some embodiments of the present application provide an electrode assembly 12, wherein the electrode assembly 12 is a laminated structure, the electrode assembly 12 includes a plurality of first electrode sheets 121 stacked along a first direction, each first electrode sheet 121 includes a first coating region 1211, a second coating region 1213 and a first tab region 1212, the second coating region 1213 and the first coating region 1211 are connected by the first tab region 1212, and projections of the first tab regions 1212 of the plurality of first electrode sheets 121 overlap along the first direction; the length L ₁ of each first pole piece is the same, the length L ₁₂ of the first coating regions of the plurality of first pole pieces 121 gradually increases from two sides to the middle in the first direction, the length L ₁₃ of the second coating regions of the plurality of first pole pieces 121 gradually increases from two sides to the middle in the first direction, and the length L ₁₁ of the first tab regions of the plurality of first pole pieces 121 gradually decreases from two sides to the middle in the first direction.

Referring to fig. 3 to 13, and further referring to fig. 14 to 18, fig. 14 is a front cross-sectional view of a battery cell according to some embodiments of the present application; fig. 15 is an enlarged schematic view of a partial structure of a portion C shown in fig. 14; FIG. 16 is a front view of a first adapter provided in some embodiments of the present application; FIG. 17 is a bottom view of a first adapter provided in some embodiments of the present application; fig. 18 is a bottom view of a first adapter provided in accordance with still further embodiments of the present application. Some embodiments of the present application also provide a battery cell 10 including an electrode assembly 12, a case assembly 11, and a first adapter 13, wherein the electrode assembly 12 may be the electrode assembly 12 according to any one of the foregoing embodiments, and the first tab region 1212 of the electrode assembly 12 is bent such that a projection of the first coating region 1211 in a thickness direction thereof overlaps a projection of the second coating region 1213 in a thickness direction thereof. The electrode assembly 12 is accommodated in the case assembly 11, and the case assembly 11 includes a first electrode lead-out portion, and the first adapter 13 is electrically connected to the first tab regions 1212 of the plurality of first electrode tabs 121 and the first electrode lead-out portion.

Before the first tab region 1212 is bent, since the plurality of first electrode tabs 121 of the electrode assembly 12 are stacked in the first direction X, the thickness directions of the first and second coating regions 1211 and 1213 are each extended in the first direction X, and after the first tab region 1212 is bent, the thickness directions of the first and second coating regions 1211 and 1213 are each extended in the second direction Y. The first tab region 1212 is located at one side of the first and second coating regions 1211 and 1213 in the first direction X.

The structure of the case assembly 11 may be referred to as the above-described structure, wherein the first electrode lead-out portion 113 may be an electrode terminal, a tab-type electrode post, or other means for outputting the current of the electrode assembly 12, and the polarity of the first electrode lead-out portion 113 is the same as the polarity of the first tab region 1212.

The first transfer member 13 plays a role of overcurrent and bus, and the first electrode lead-out portion 113 is electrically connected to the first tab region 1212 through the first transfer member 13.

It will be appreciated that the battery cell 10 may also include a second power lead-out and a second adapter, which electrically connects the second tab 1222 and the second power lead-out, respectively.

The first tab region 1212 is bent such that the thickness directions of the first and second coating regions 1211 and 1213 are identical, the first tab region 1212 is positioned at the same side of the first and second coating regions 1211 and 1213, the electrode assembly 12 is received in the case assembly 11, and the first adapter 13 connects the first tab region 1212 and the first electrode lead-out portion, forming the battery cell 10, which has superior performance stability and has higher energy density.

According to some embodiments of the present application, referring to fig. 14 to 18, the first adaptor 13 includes a body 131, a first arm 132 and a second arm 133, the body 131 is connected to the first electrode lead-out portion, the first arm 132 and the second arm 133 extend from one end of the body 131, a gap 134 is formed between the first arm 132 and the second arm 133, and a plurality of first tab regions 1212 of the first pole pieces 121 are inserted into the gap 134 and connected to the first arm 132 and the second arm 133.

The body 131 may be implemented in various structures, such as a plate shape, a block shape, and the body 131 is exemplified as a plate shape.

It is understood that the first arm 132 and the second arm 133 may be disposed at intervals along the first direction X, and the first arm 132 and the second arm 133 may be integrally formed with the body 131 or may be disposed separately from the body 131.

As shown in fig. 18, the first adapter 13 may be a plate-like structure having a side wall in the thickness direction thereof, a groove being provided in the side wall, the groove forming the above-mentioned gap 134, and two wall portions of the groove forming the first arm 132 and the second arm 133.

The first adapter 13 includes a body 131 and a first arm 132 and a second arm 133 extending from the same end of the body 131, and a gap 134 is provided between the first arm 132 and the second arm 133 for inserting the first tab region 1212, so that after the first tab region 1212 is connected with the first electrode lead-out portion through the first adapter 13 with such a structure, the first arm 132 and the second arm 133 of the first adapter 13 play a fastening and limiting role on the first tab region 1212, and the risk that the first tab region 1212 collapses to the first coating region 1211 and the second coating region 1213 is reduced, thereby reducing the risk that the battery cell 10 is short-circuited due to deformation of the first tab region 1212, and further effectively improving the performance stability of the battery cell 10.

According to some embodiments of the present application, the present application also provides a battery 100, including the battery cell 10 according to any one of the above aspects.

According to some embodiments of the present application, the present application further provides an electric device, including the battery 100 according to the above scheme, where the battery 100 is used to provide electric energy.

The power utilization device may be any of the devices or systems described above that employ the battery 100.

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

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

Claims

An electrode assembly, characterized in that the electrode assembly is of a laminated structure, the electrode assembly comprises a plurality of first pole pieces which are laminated along a first direction, each first pole piece comprises a first coating area, a second coating area and a first tab area, the second coating area and the first coating area are connected through the first tab area, and projections of the first tab areas of the plurality of first pole pieces overlap along the first direction;

Wherein the electrode assembly satisfies one of the following conditions:

a) The lengths of the first tab areas of the plurality of first pole pieces gradually decrease from one side to the other side in the first direction;

b) The lengths of the first tab regions of the plurality of first pole pieces gradually decrease from two sides to the middle in the first direction.
The electrode assembly of claim 1, wherein each of the first pole pieces is the same length;

when the electrode assembly satisfies the above condition a), the electrode assembly simultaneously satisfies:

The lengths of the first coating regions of the plurality of first pole pieces gradually increase from one side to the other side in the first direction, and the lengths of the second coating regions of the plurality of first pole pieces gradually increase from one side to the other side in the first direction.
The electrode assembly of claim 1, wherein each of the first pole pieces is the same length;

when the electrode assembly satisfies the above condition b), the electrode assembly simultaneously satisfies:

The lengths of the first coating regions of the plurality of first pole pieces gradually increase from two sides in the first direction to the middle, and the lengths of the second coating regions of the plurality of first pole pieces gradually increase from two sides in the first direction to the middle.
The electrode assembly according to claim 2 or 3, wherein a ratio of the length of the first coating region having the shortest length to the length of the first coating region having the longest length is 0.9 or more; and/or

The ratio of the length of the second coating region with the shortest length to the length of the second coating region with the longest length is more than or equal to 0.9.
The electrode assembly of any one of claims 2-4, wherein the ratio of the length of the first coated region to the length of the first tab region of the same first pole piece is D ₁, satisfying 1.4 ∈d ₁ ∈1.8; and/or

The ratio of the length of the second coating area to the length of the first tab area of the same first pole piece is D ₂, and D ₂ is less than or equal to 1.4 and less than or equal to 1.8.
The electrode assembly of any one of claims 1-5, wherein the difference in length between adjacent two of the first tab regions in the first direction is D ₃, satisfying 0.004mm ∈d ₃ ∈0.008mm.
The electrode assembly of any one of claims 1-6, further comprising a plurality of second electrode sheets, the plurality of first electrode sheets and the plurality of second electrode sheets being alternately stacked in the first direction, the first electrode sheets and the second electrode sheets being of opposite polarity, the second electrode sheets comprising a third coated region, a fourth coated region, and a second electrode ear region, the third coated region and the fourth coated region being connected by the second electrode ear region, projections of the second electrode ear regions of the plurality of second electrode sheets overlapping in the first direction;

Wherein the electrode assembly satisfies one of the following conditions:

c) The lengths of the second lug areas of the plurality of second pole pieces are gradually reduced from one side to the other side in the first direction;

d) The lengths of the second lug areas of the plurality of second pole pieces are gradually reduced from two sides to the middle in the first direction.
The electrode assembly of claim 7, wherein each of the second pole pieces is the same length;

when the electrode assembly satisfies the above condition c), the electrode assembly simultaneously satisfies:

The lengths of the third coating regions of the plurality of second pole pieces gradually increase from one side to the other side in the first direction, and the lengths of the fourth coating regions of the plurality of second pole pieces gradually increase from one side to the other side in the first direction.
The electrode assembly of claim 7, wherein each of the second pole pieces is the same length;

when the electrode assembly satisfies the above condition d), the electrode assembly simultaneously satisfies:

The lengths of the third coating regions of the plurality of second pole pieces gradually increase from both sides in the first direction to the middle, and the lengths of the fourth coating regions of the plurality of second pole pieces gradually increase from both sides in the first direction to the middle.
A battery cell, comprising:

The electrode assembly according to any one of claims 1 to 9, the first tab region being bent such that a projection of the first coating region in a thickness direction thereof overlaps a projection of the second coating region in a thickness direction thereof;

a case assembly, in which the electrode assembly is housed, the case assembly including a first electrode lead-out portion;

The first transfer piece is electrically connected with the first tab areas and the first electrode lead-out parts of the plurality of first pole pieces.
The battery cell of claim 10, wherein the first adapter comprises a body, a first arm, and a second arm, the body being connected to the first electrode lead-out, the first arm and the second arm extending from one end of the body, a gap being provided between the first arm and the second arm, the first tab regions of the plurality of first pole pieces being inserted into the gap and connected to the first arm and the second arm.
A battery comprising a battery cell according to claim 10 or 11.
An electrical device comprising a battery as claimed in claim 12, said battery being arranged to provide electrical energy.