Electrode assembly, battery and battery module

Abstract

The utility model provides an electrode assembly, a battery and a battery module, the electrode assembly comprises a pole piece structure and at least one tab structure, the pole piece structure comprises a plurality of pole piece bodies laminated along a first direction, and each pole piece body comprises a connecting end in a second direction crossed with the first direction; the tab structure comprises a plurality of tab bodies, and the tab bodies are connected with the connecting ends of the corresponding pole piece bodies and extend in the second direction; wherein the sizes of at least two adjacent tab bodies are different; the tab bodies with different sizes are arranged in the tab structure, and the plurality of tab bodies with different sizes are stacked together, so that the tab bodies can be conveniently clamped together by a tool clamp in the related technology, and the plurality of layers of tab bodies are ensured to be welded together during ultrasonic welding after the tab structure is bent; therefore, the tail ends, deviating from the tab structure, of the plurality of bent tab bodies are basically aligned with one another, and the welding ranges of the plurality of tab bodies are consistent, so that the risk of missing welding is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an electrode assembly, a battery and a battery module. Background Art

[0002] Lithium-ion batteries belong to a metastable system and are very sensitive to temperature. Excessive temperature will significantly accelerate the attenuation rate of lithium-ion batteries. In related technologies, to control the temperature of lithium-ion batteries, the internal resistance of the battery can be reduced by increasing the number of tab layers, thereby increasing the uniformity of the current density distribution, reducing the polarization during the charge and discharge process of the battery, and lowering the overall temperature of the battery. However, due to the increase in the number of tab layers, it is difficult to ensure that each layer of tabs is welded together during the battery assembly and forming process, and it is difficult to ensure that the welding ranges between multiple tabs are all consistent, resulting in inconsistent internal resistance of the battery and thus poor battery consistency. Summary of the Utility Model

[0003] Embodiments of the utility model provide an electrode assembly, a battery and a battery module, which can improve the technical problems in the related art that when the number of tab layers is large, it is difficult to weld the tabs together during the battery assembly process, and it is difficult to ensure that the welding ranges between multiple tabs are all consistent, resulting in inconsistent internal resistance of the battery.

[0004] In a first aspect, embodiments of the utility model provide an electrode assembly, including:

[0005] A pole piece structure, including a plurality of pole piece bodies stacked in a first direction, and the pole piece body includes a connection end in a second direction intersecting the first direction; and

[0006] At least one tab structure, including a plurality of tab bodies, the plurality of tab bodies corresponding to the plurality of pole piece bodies one by one, and the tab body is connected to the connection end of the corresponding pole piece body and extends in the second direction;

[0007] Wherein, the sizes of at least two adjacent tab bodies are different.

[0008] In an embodiment, among two adjacent tab bodies, the orthographic projection of one tab body in the first direction completely falls on the other tab body.

[0009] In an embodiment, the tab structure includes a welding surface in the first direction, and the welding surface is configured to be welded to an output pole;

[0010] Wherein, the size of the tab body close to the welding surface is larger than the size of the tab body far from the welding surface.

[0011] In an embodiment, in the first direction, the sizes of the plurality of tab bodies in the second direction decrease in sequence.

[0012] In one embodiment, in two adjacent tab bodies, the shortest distance from the projection of the periphery of one tab body on the welding surface to the projection of the periphery of the other tab body on the welding surface is defined as D; wherein D satisfies: 0mm≤D≤2mm.

[0013] In one embodiment, the length of the tab body in the second direction is defined as L1; wherein L1 satisfies: 15 mm ≤ L1 ≤ 23 mm.

[0014] In one embodiment, the tab body is arranged in a trapezoidal shape.

[0015] In one embodiment, the tab body comprises a first side and a second side arranged opposite to each other in the second direction. The first side is located at the junction of the tab body and the pole piece body.

[0016] The length of the first side in the third direction is defined as L2, the length of the second side in the third direction is defined as L3, and the first direction and the second direction are respectively perpendicular to the third direction; wherein L2 and L3 satisfy: 41mm≤L2≤47mm, 34mm≤L3≤40mm.

[0017] In a second aspect, an embodiment of the utility model provides a battery, comprising:

[0018] at least one electrode assembly; and

[0019] The cover plate assembly is connected to the pole ear structure of the electrode assembly.

[0020] In a third aspect, an embodiment of the present utility model provides a battery module, including a battery.

[0021] Beneficial effects of the embodiments of the utility model:

[0022] In the technical solution of the utility model, by arranging pole lug bodies of different sizes in the pole lug structure, a plurality of pole lug bodies of different sizes are stacked together, so as to facilitate the tooling fixture in the related technology to clamp them together, and ensure that after the pole lug structure is bent, the multiple layers of pole lug bodies are welded together during ultrasonic welding, so that the ends of the multiple pole lug bodies away from the pole lug structure after bending are basically aligned with each other, and the welding ranges between the multiple pole lug bodies are consistent, so as to avoid the risk of welding leaks. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a three-dimensional schematic diagram of the internal electrode assembly of the battery provided by the embodiment of the present utility model;

[0025] Figure 2 is Figure 1 an enlarged schematic diagram of part A in

[0026] Figure 3 It is a structural schematic diagram of the internal electrode assembly of the battery provided by the embodiment of the present utility model;

[0027] Figure 4 It is a structural schematic diagram of the tab body provided by the embodiment of the present utility model;

[0028] Figure 5 It is an arrangement schematic diagram of part of the tab bodies in the tab structure provided by the embodiment of the present utility model;

[0029] Figure 6 It is a temperature change diagram of the terminal post when the battery provided by the embodiment of the present utility model and the battery in the related art are charged at the current of the nominal capacity;

[0030] Figure 7 It is a temperature change diagram of the large surface of the battery when the battery provided by the embodiment of the present utility model and the battery in the related art are charged at the current of the nominal capacity;

[0031] Figure 8 It is a DC internal resistance change diagram of the battery provided by the embodiment of the present utility model and the battery in the related art during charging;

[0032] Figure 9 It is a DC internal resistance change diagram of the battery provided by the embodiment of the present utility model and the battery in the related art during discharging. Description of the drawings:

[0034] 1. Electrode structure; 11. Electrode body; 10. Connection end; 2. Tab structure; 21. Tab body; 3. First side; 4. Second side; 5. Welding surface. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative efforts belong to the scope of protection of the present utility model. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present utility model, and are not used to limit the present utility model. In the present utility model, unless otherwise stated, the orientation words such as "upper" and "lower" usually refer to the upper and lower in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings; and "inner" and "outer" refer to the outline of the device.

[0036] This application provides an electrode assembly. Figures 1 to 9 These are some embodiments of this application.

[0037] Among them, the X direction in the accompanying drawings is the third direction, the Y direction is the first direction, and the Z direction is the second direction. The first direction and the second direction intersect with each other, and the first direction and the second direction are respectively perpendicular to the third direction; in an embodiment of this application, the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0038] Please refer to Figures 1 to 3 , in some embodiments of this application, the electrode assembly includes a pole piece structure 1 and at least one tab structure 2. The tab structure 2 is located at one end of the pole piece structure 1 and is connected to the pole piece structure 1.

[0039] The pole piece structure 1 includes a plurality of pole piece bodies 11 stacked along the first direction Y. In one embodiment, the plurality of pole piece bodies 11 are integrally formed and wound together to form the pole piece structure 1; in another embodiment, the plurality of pole piece bodies 11 are stacked.

[0040] Among them, when the plurality of pole piece bodies 11 are stacked, it can be that the plurality of pole piece bodies 11 all exist independently, and there is no connection between two adjacent pole piece bodies 11; it can also be that the pole piece body 11 bends reciprocally in the first direction Y, so that at least part of the reciprocally bent pole piece body 11 can be opposite in the first direction Y, and on the basis that the pole piece body 11 bends reciprocally in the first direction Y, the plurality of pole piece bodies 11 are stacked together.

[0041] In an embodiment of this application, the plurality of pole piece bodies 11 are integrally formed and wound together to form the pole piece structure 1. That is, in this embodiment, the electrode assembly is formed by winding a positive electrode pole piece, a negative electrode pole piece, and a separator. The pole piece body 11 is a partial structure of the positive electrode pole piece and the negative electrode pole piece, and the tab body 21 connected to the positive electrode pole piece is a positive tab, and the tab body 21 connected to the negative electrode pole piece is a negative tab.

[0042] Each pole piece body 11 includes a connection end 10 in the second direction Z. The tab structure 2 includes a plurality of tab bodies 21, and the plurality of tab bodies 21 correspond to the plurality of pole piece bodies 11 one by one. In the unbent state of the tab structure 2, the tab body 21 is connected to the connection end 10 of the corresponding pole piece body 11 and extends along the second direction Z; that is, in this embodiment, one tab body 21 is provided on one pole piece body 11. By increasing the number of tab bodies 21 in the electrode assembly, the internal resistance of the battery is reduced, the current density is balanced, the temperature during the operation of the battery is reduced, and the battery performance is improved. The plurality of tab bodies 21 are naturally stacked during the winding process of the electrode assembly, so as not to affect the production rhythm of the production line.

[0043] Among them, the sizes of at least two adjacent tab bodies 21 are different.

[0044] That is, in the technical solution of the present utility model, by providing tab bodies 21 with different sizes in the tab structure 2, the plurality of tab bodies 21 with different sizes are stacked together, so that the tooling fixtures in the related art can clamp them together, ensuring that after the tab structure 2 is bent, when ultrasonic welding, the multiple tab bodies 21 are welded together, so that the ends of the multiple tab bodies 21 facing away from the tab structure 2 are basically aligned with each other, and the welding ranges between the multiple tab bodies 21 are the same, so as to avoid the risk of missed welding.

[0045] In some embodiments of the present application, among two adjacent tab bodies 21, the orthographic projection of one tab body 21 in the first direction Y completely falls on the other tab body 21. That is, by setting like this, the welding area between the two adjacent tab bodies 21 can be increased, thereby improving the consistency of the internal resistance of the battery.

[0046] In some embodiments of the present application, the tab structure includes a welding surface 5 in the first direction Y, and the welding surface 5 is configured to be welded to the output pole, that is, the welding surface 5 is directly welded to the pole column on the cover plate assembly or indirectly welded to the pole column through a connecting piece.

[0047] Among them, the size of the tab body 21 close to the welding surface 5 is larger than the size of the tab body 21 far from the welding surface 5; in this embodiment, in the process step of inserting the electrode assembly into the case after welding the plurality of tab bodies 21 to the cover plate assembly of the battery, the positional relationship between the electrode assembly and the cover plate assembly needs to be adjusted, that is, the plurality of tab bodies 21 will be bent. Since the sizes of the plurality of tab bodies 21 are different, the size of one or more tab bodies 21 close to the welding surface 5 is larger than the size of one or more tab bodies 21 far from the welding surface 5, and the risk of tearing or reverse insertion of the tab body 21 can be reduced when the plurality of tab bodies 21 are bent.

[0048] In some embodiments of the present application, in the first direction Y, the sizes of the plurality of tab bodies 21 decrease in sequence in the second direction Z. Among them, since the tab structure 1 includes a welding surface 5 in the first direction Y, in this embodiment, the plurality of tab bodies 21 decrease in sequence in the direction away from the welding surface 5.

[0049] The sizes of the plurality of tab bodies 21 decrease in sequence in the second direction Z, that is, the sizes between the plurality of tab bodies 21 are different. By providing tab bodies 21 with different sizes in the tab structure 2, the plurality of tab bodies 21 with different sizes are stacked together, so that the tooling fixtures in the related art can clamp them together, ensuring that when the tab structure 2 is bent, multiple layers of tab bodies 21 are welded together during ultrasonic welding to avoid the risk of missed welding. At the same time, the risk of tearing or reverse insertion of the tab bodies 21 can also be reduced when the plurality of tab bodies 21 are bent.

[0050] In addition, since the sizes of the plurality of tab bodies 21 decrease in sequence in the first direction Y, the safety risk of short circuit caused by the insertion of some tab bodies 21 into the tab structure 1 or the overlap between the tab bodies 21 and the cover plate assembly of the battery after the battery assembly is completed can also be reduced.

[0051] Please refer to Figure 4 , in some embodiments of the present application, the length of the tab body 21 in the second direction Z is defined as L1; wherein, L1 satisfies: 15 mm ≤ L1 ≤ 23 mm. That is, in this embodiment, L1 satisfies the range of 15 mm ≤ L1 ≤ 23 mm to ensure that the plurality of tab bodies 21 in the tab structure 2 can be welded together, and the welding ranges between the plurality of tab bodies 21 are all complete and consistent. If L1 is less than 15 mm, the risk of incomplete welding between the plurality of tab bodies 21 may occur. If L1 is greater than 23 mm, the safety risk of short circuit may be caused by the too long length of the tab body 21, resulting in the insertion of the tab body 21 into the tab structure 1 or the overlap between the tab body 21 and the cover plate assembly of the battery.

[0052] Among them, the value of L1 can be 15mm, 15.2mm, 15.4mm, 15.6mm, 15.8mm, 16mm, 16.2mm, 16.4mm, 16.6mm, 16.8mm, 17mm, 17.2mm, 17.4mm, 17.6mm, 17.8mm, 18mm, 18.2mm, 18.4mm, 18.6mm, 18.8mm, 19mm, 19.2mm, 19.4mm, 19.6mm, 19.8mm, 20mm, 20.2mm, 20.4mm, 20.6mm, 20.8mm, 21mm, 21.2mm, 21.4mm, 21.6mm, 21.8mm, 22mm, 22.2mm, 22.4mm, 22.6mm, 22.8mm, 23mm. The value of L1 is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0053] In some embodiments of the present application, the tab body 21 is trapezoidally arranged. That is, the trapezoidally arranged tab body 21 can reduce the weight and occupied space of the tab structure 2 on the basis of not affecting the firm welding between multiple tab bodies 21, thereby improving the energy density of the electrode assembly.

[0054] In some embodiments of the present application, the tab body 21 includes a first side 3 and a second side 4 that are oppositely arranged in the second direction Z. The first side 3 is located at the junction of the tab body 21 and the tab sheet body 11; define the length of the first side 3 in the third direction Y as L2, and the length of the second side 4 in the third direction Y as L3; among them, L2 and L3 satisfy: 41mm ≤ L2 ≤ 47mm, 34mm ≤ L3 ≤ 40mm. That is, in this embodiment, L2 and L3 satisfy the interval range of 41mm ≤ L2 ≤ 47mm, 34mm ≤ L3 ≤ 40mm to ensure that multiple tab bodies 21 in the tab structure 2 can be completely welded, and the welding ranges between multiple tab bodies 21 are all complete and consistent, while avoiding the situation where the welding area between multiple tab bodies 21 is too small, resulting in an increase in the internal resistance of the electrode assembly. If L2 is less than 41mm or L3 is less than 34mm, there may be a risk that the welding area between multiple tab bodies 21 is too small, resulting in an increase in the internal resistance of the electrode assembly; if L2 is greater than 47mm or L3 is greater than 40mm, there may be a safety risk of short circuit caused by the overlap of the tab body 21 and the battery cover assembly.

[0055] Among them, the values of L2 and L3 match to ensure that the tab body 21 can be trapezoidally arranged.

[0056] The value of L2 can be 41mm, 41.2mm, 41.4mm, 41.6mm, 41.8mm, 42mm, 42.2mm, 42.4mm, 42.6mm, 42.8mm, 43mm, 43.2mm, 43.4mm, 43.6mm, 43.8mm, 44mm, 44.2mm, 44.4mm, 44.6mm, 44.8mm, 45mm, 45.2mm, 45.4mm, 45.6mm, 45.8mm, 46mm, 46.2mm, 46.4mm, 46.6mm, 46.8mm, 47mm. The value of L2 is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0057] The value of L3 can be 34mm, 34.2mm, 34.4mm, 34.6mm, 34.8mm, 35mm, 35.2mm, 35.4mm, 35.6mm, 35.8mm, 36mm, 36.2mm, 36.4mm, 36.6mm, 36.8mm, 37mm, 37.2mm, 37.4mm, 37.6mm, 37.8mm, 38mm, 38.2mm, 38.4mm, 38.6mm, 38.8mm, 39mm, 39.2mm, 39.4mm, 39.6mm, 39.8mm, 40mm. The value of L3 is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0058] Please refer to Figure 5 , in some embodiments of the present application, among two adjacent tab bodies 21, the shortest distance from the projection of the periphery of one tab body 21 on the welding surface 5 to the projection of the periphery of the other tab body 21 on the welding surface 5 is defined as D; wherein, D satisfies: 0mm < D ≤ 2mm. Among them, the front projection of the tab structure 2 in the first direction Y is trapezoidally arranged. In this embodiment, it is designed that D satisfies the interval range of 0mm < D ≤ 2mm, so that the height range of the front projection of the tab structure 2 trapezoidally arranged in the first direction Y in the first direction Y is maintained between 15mm and 23mm, the length range of the upper base in the third direction Y is maintained between 34mm and 40mm, and the length range of the lower base in the third direction Y is maintained between 41mm and 47mm; if D is greater than 2mm, it will cause the overall size of the tab structure 2 to be too large, resulting in the safety risk of short circuit when the tab body 21 is inserted into the electrode sheet structure 1 or the tab body 21 is overlapped with the cover plate assembly of the battery.

[0059] In addition, in an embodiment of the present application, the D value can also be 0, that is, at least two tab bodies 21 have exactly the same size. However, on this basis, it is necessary to ensure that the size of the tab body 21 close to the welding surface 5 is greater than the size of the tab 21 far from the welding surface 5, and the size of the tab structure 2 in the second direction Z is in a decreasing state, so as to facilitate the clamping of the tab structure 2 together by the tooling fixtures in the related art, ensure that after the tab structure 2 is bent, the ultrasonic welding welds multiple tab bodies 21 together, so that the ends of the multiple tab bodies 21 facing away from the tab structure 2 are basically aligned with each other after bending, and the welding range between the multiple tab bodies 21 is consistent, so as to avoid the risk of missed welding.

[0060] The present application also proposes a battery, which includes at least one electrode assembly and a cover plate assembly, and the cover plate assembly is connected to the tab structure 2 of the electrode assembly. The electrode assembly is as described in the above embodiment. Since this battery adopts all the technical solutions of the above all embodiments, it has at least the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0061] In some embodiments of the present application, the number of electrode assemblies is set to two, and the two electrode assemblies are arranged in the first direction Y; the welding surfaces 5 of the two tab structures 2 are respectively connected to the cover plate assembly, so as to reduce the risk of tearing of the tab body 21 when the tab structure 2 is bent and avoid the risk of missed welding between multiple tab bodies 21.

[0062] It can be understood that the size of the tab body 21 close to the welding surface 5 is greater than the size of the tab body 21 far from the welding surface 5; in this embodiment, in the process step of inserting the electrode assembly into the shell after welding multiple tab bodies 21 to the cover plate assembly of the battery, it is necessary to adjust the positional relationship between the electrode assembly and the cover plate assembly, that is, multiple tab bodies 21 will be bent. Since the sizes of multiple tab bodies 21 are different, the size of one or more tab bodies 21 close to the welding surface 5 is greater than the size of one or more tab bodies 21 far from the welding surface 5, and the risk of tearing of the tab body 21 can be reduced when multiple tab bodies 21 are bent.

[0063] In addition, multiple tab bodies 21 with different sizes are stacked together, so as to facilitate the clamping of the tab structure 2 together by the tooling fixtures in the related art, ensure that after the tab structure 2 is bent, the ultrasonic welding welds multiple tab bodies 21 together, so that the ends of the multiple tab bodies 21 facing away from the tab structure 2 are basically aligned with each other after bending, and the welding range between the multiple tab bodies 21 is consistent, so as to avoid the risk of missed welding.

[0064] The battery in the related art is a lithium iron phosphate battery and the electrode assembly is a wound core. The number of winding turns is 25 turns for the positive electrode tab and 26 turns for the negative electrode tab. Among them, there are 26 layers of negative electrode tabs and 25 layers of positive electrode tabs. Then, the number of positive electrode ears in one wound core is 25, and the number of negative electrode ears is 26. On this basis, the battery is charged and discharged at the current of its nominal capacity. At this time, the highest temperature of the terminal post is 39 °C, and the temperature of the large surface of the battery is 42 °C.

[0065] In an embodiment of the present application, the battery is a lithium iron phosphate battery and the electrode assembly is a wound core. When the number of winding turns is 25 turns for the positive electrode tab and 26 turns for the negative electrode tab, there are 50 positive electrode ears and 52 negative electrode ears in one wound core. At this time, the highest temperature of the terminal post is 36 °C, and the temperature of the large surface of the battery is 40 °C.

[0066] In addition, if the number of positive electrode ears is between 25 and 50, and the number of negative electrode ears is between 26 and 52, such as 38 positive electrode ears and 40 negative electrode ears, then the highest temperature of the terminal post is between 36 °C and 39 °C, and the temperature of the large surface of the battery is between 40 °C and 42 °C.

[0067] Please refer to Figures 6 to 9 , label B refers to the battery with 25 positive electrode ears and 26 negative electrode ears in the electrode assembly; label C refers to the battery with 50 positive electrode ears and 52 negative electrode ears in the electrode assembly; label D refers to the battery with 38 positive electrode ears and 40 negative electrode ears in the electrode assembly.

[0068] Please refer to Figures 6 to 7 , Figure 6 is the graph of the temperature rise change of the terminal post when B, C, and D are charged at the current of their nominal capacity, Figure 7 is the graph of the temperature rise change of the large surface of the battery when B, C, and D are charged at the current of their nominal capacity.

[0069] Please refer to Figures 8 to 9 , Figures 8 to 9 is the graph of the relationship between the direct current resistance (DCR) and the state of charge (SOC) of B, C, and D during charging; among them, Figure 8 is the graph of the change of the direct current resistance of the battery under the charging state, Figure 9 is the graph of the change of the direct current resistance of the battery under the discharging state.

[0070] To sum up, from Figures 6 to 7It can be known that the more the number of tabs in the battery, the lower the internal resistance of the battery. A lower battery internal resistance means a smaller voltage drop and lower loss inside the battery, resulting in a higher energy efficiency for charging and discharging. When the battery internal resistance is relatively low, both its ohmic internal resistance and polarization internal resistance will decrease, which will lead to a reduction in the heat generated during the operation of the battery. That is, the temperature rise of the battery proposed in the embodiments of the present application during use is lower than that of the battery in the related art during use. Therefore, the heat generated during the operation of the battery can be effectively reduced.

[0071] It can be known from Figures 8 to 9 that during the charging process, the internal resistance of the battery increases with the increase in the state of charge; during the discharging process, the DC internal resistance of the lithium-ion battery increases with the decrease in the state of charge. However, during the charging and discharging processes, the DC internal resistance of the battery proposed in the present application is smaller than that of the battery in the related art. Therefore, the DC internal resistance of the battery proposed in the present application is relatively low, thus effectively reducing the heat generated during the operation of the battery.

[0072] The present application also proposes a battery module. The battery module includes at least one battery, and the battery is as described in the above embodiments. Since this battery module adopts all the technical solutions of the above embodiments, it has at least the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0073] The above has introduced the embodiments of the present utility model in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model; at the same time, for those skilled in the art, based on the idea of the present utility model, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present utility model.

Claims

1. An electrode assembly, characterized in that: include: A pole piece structure, comprising a plurality of pole piece bodies stacked along a first direction, wherein the pole piece bodies include a connection end in a second direction intersecting the first direction; and At least one pole lug structure, comprising a plurality of pole lug bodies, wherein the pole lug bodies are connected to the connecting ends of the corresponding pole piece bodies and extend along the second direction; Wherein, at least two adjacent tab bodies have different sizes.

2. The electrode assembly according to claim 1, characterized in that: Of the two adjacent tab bodies, the orthographic projection of one tab body in the first direction completely falls on the other tab body.

3. The electrode assembly according to claim 2, characterized in that: The pole ear structure comprises a welding surface located in the first direction, and the welding surface is configured to be welded with the output pole; Wherein, the size of the tab body close to the welding surface is greater than the size of the tab body far from the welding surface.

4. The electrode assembly according to claim 3, characterized in that: In the first direction, the sizes of the plurality of tab bodies in the second direction decrease in sequence.

5. The electrode assembly according to claim 3, characterized in that: In two adjacent tab bodies, the shortest distance from the projection of the periphery of one tab body on the welding surface to the projection of the periphery of the other tab body on the welding surface is defined as D; wherein D satisfies: 0mm≤D≤2mm.

6. The electrode assembly according to any one of claims 1 to 5, characterized in that: The length of the tab body in the second direction is defined as L1; wherein L1 satisfies: 15 mm ≤ L1 ≤ 23 mm.

7. The electrode assembly according to any one of claims 1 to 5, characterized in that: The tab body is arranged in a trapezoidal shape.

8. The electrode assembly according to claim 7, characterized in that: The pole tab body comprises a first side and a second side which are arranged opposite to each other in a second direction, wherein the first side is located at the junction of the pole tab body and the pole piece body; Define the length of the first side in the third direction as L2, the length of the second side in the third direction as L3, and the first direction and the second direction are respectively perpendicular to the third direction; wherein, L2 and L3 satisfy: 41mm≤L2≤47mm, 34mm≤L3≤40mm.

9. A battery, characterized in that: include: At least one electrode assembly according to any one of claims 1 to 8; and A cover plate assembly is connected to the tab structure of the electrode assembly.

10. A battery module, characterized in that: Comprising at least one battery as claimed in claim 9.

Images