Cylindrical electrode assembly

Abstract

The utility model relates to a cylinder electrode assembly, including main part and tab part, the main part is wound into the cylinder shape, the tab part is connected with the main part end portion, the tab part includes a plurality of layers of tabs, each layer of tab has a first end portion and a second end portion in the height direction, the first end portion is connected with the main part, and the second end portion is connected with the main part. The plurality of layers of tabs of the same tab part are sequentially overlapped, the first end parts of the plurality of layers of tabs of the same tab part are sequentially arranged along the radial direction of the main body part, and the plurality of layers of tabs of the same tab part lodging towards the central side of the main body part to form a flattening tab area; in the multiple layers of tabs which are sequentially stacked in the radial direction of the main body part away from the center of the main body part, the heights of the tabs from the first layer to the Nth layer are gradually increased, and the heights of the tabs from the Nth layer to the Mth layer are the same; wherein N is a positive integer greater than 1, and M is a positive integer greater than N. According to the utility model, the welding size of the leveling tab area along the radius direction of the main body part can be increased, the transmission distance of electrons is reduced, the internal resistance and polarization of the battery are reduced, and the performance of the battery is improved.

Description

Technical Field

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

[0002] With the development of new energy vehicles, cylindrical batteries have become a development trend due to their advantages of high energy density and low cost.

[0003] The patent with publication number WO2022 / 061187A1 discloses a tab shape of a tab-free battery, with the tabs having the same height; the tabs are cut into parallelogram shapes by laser slit cutting, and this design can form a welding surface through the flattening process; but the tabs on both sides of the core will cause space waste, resulting in a low energy density of the battery cell. The tab distribution algorithm can be used to achieve the fan-shaped area distribution of the positive and negative tabs at one end of the cylinder on the laser-winding machine, and then form a welding surface by flattening. In the flattening process, it was found that the flattening and welding of the highly consistent positive and negative tabs (parallelogram design) have the following problems: after the core with consistent tab height is flattened, the tab flattening thickness of the core along the radial direction gradually increases, then remains unchanged, and then gradually decreases. In order to ensure the welding effect with the adapter (avoid over-welding and penetration), it is necessary to select the area with the same tab flattening thickness for welding; therefore, the welding size in the radial direction of the core is limited. After being assembled into a battery, the core current capacity is limited, the internal resistance of the battery is increased, and the performance is reduced. How to provide a method to increase the welding size of the pole ear in the radial direction of the winding core is a technical problem to be solved urgently in this field Utility Model Content

[0004] Therefore, the technical problem to be solved by the present invention is to provide a cylindrical electrode assembly capable of increasing the welding size of the electrode tab in the radial direction of the winding core.

[0005] In order to solve the above technical problems, the utility model provides a cylindrical electrode assembly, including a main body and a pole ear part, wherein the main body is wound into a main body shape, the pole ear part is connected to the end of the main body, the pole ear part includes multiple layers of pole ears, each layer of the pole ears has a first end and a second end in the height direction, the first end is connected to the main body, the multiple layers of pole ears of the same pole ear part are stacked in sequence, and the first ends of the multiple layers of pole ears of the same pole ear part are arranged in sequence along the radial direction of the main body, and the multiple layers of pole ears of the same pole ear part are collapsed toward the center side of the main body to form a flattened pole ear area;

[0006] In the multiple layers of pole lugs stacked in sequence along the radial direction of the main body away from the center of the main body, the heights of the pole lugs of the first to N layers gradually increase, and the heights of the pole lugs of the Nth to M layers are the same;

[0007] Wherein, N is a positive integer greater than 1, and M is a positive integer greater than N.

[0008] Furthermore, in the multiple layers of pole lugs of the same pole lug portion, in the first to Nth layers of pole lugs, the height difference between two adjacent layers of pole lugs is equal to the distance between two adjacent layers of pole lugs along the radial direction of the main body portion.

[0009] Further, after the first layer of the pole lugs is collapsed, the second end of the pole lugs is located at position A, after the first layer of the pole lugs is collapsed, the first end of the pole lugs of the Nth layer is collapsed, the first end of the pole lugs of the Mth layer is collapsed, the second end of the pole lugs of the Mth layer is collapsed, and the first end of the pole lugs (21) ...

[0010] The dimension of the flattened tab area measured along the axial direction of the main body is the thickness of the flattened tab area;

[0011] The thickness of the flattened lug area at position A is δ1; the thickness of the flattened lug area at position B is δ2; the thickness of the flattened lug area at position C is δ3; the thickness of the flattened lug area at position D is δ4;

[0012] δ1=T*(n+X1 / d); δ2=T*(n+2X1 / d); δ3=T*(n+X1 / d); δ4=T*(n+X1 / d);

[0013] Wherein, T is the thickness of each layer of tab;

[0014] n = N-1;

[0015] d is the distance between two adjacent layers of the pole lugs (21) along the radial direction of the main body;

[0016] X1 is the height of the first layer of tabs;

[0017] The thickness of the flattened lug area between position A and position B gradually increases, the thickness of the flattened lug area between position B and position C gradually decreases, the thickness of the flattened lug area between position C and position D is the same, and the thickness of the flattened lug area between position D and position E gradually decreases.

[0018] Furthermore, the weldable dimension of the flattened tab area measured along the radial direction of the main body is L; L = R - R0 - Xn;

[0019] Wherein, R is the radius of the main body;

[0020] R0 is the distance between the position A of the flattened tab area and the center of the main body;

[0021] Xn is the height of the tabs in the nth layer.

[0022] Furthermore, the multiple layers of the pole lugs of the same pole lug portion fall toward the center side of the main body portion, and the flattened pole lug area is in a fan-ring shape concentric with the main body portion.

[0023] Furthermore, each layer of the pole lug includes a plurality of pole lug sheets arranged in sequence along the length direction thereof, each of the pole lug sheets has a first side and a second side in the height direction, the first side is connected to the main body, and each of the pole lug sheets has a third side and a fourth side in the length direction, one end of the third side is connected to one end of the second side through an arc angle transition and / or one end of the fourth side is connected to the other end of the second side through an arc angle transition.

[0024] Furthermore, the plurality of pole tab sheets are formed by cutting a single layer of pole tab slits.

[0025] Furthermore, a through hole is provided at the center of the main body along its axial direction, and a preset distance R0 is provided between the position A of the flattened tab area and the through hole.

[0026] Furthermore, the main body includes a first pole piece, a first diaphragm, a second pole piece and a second diaphragm which are stacked in sequence, and one of the first pole piece and the second pole piece is a positive pole piece, and the other is a negative pole piece.

[0027] Furthermore, the cylindrical electrode assembly includes two pole ear portions, and the two pole ear portions are evenly distributed at the same end of the main body portion. Among the two pole ear portions, one is a positive pole ear portion, and the other is a negative pole ear portion.

[0028] The above technical solution of the utility model has the following advantages compared with the prior art:

[0029] (1) The cylindrical electrode assembly of the utility model increases the height of the first to Nth layer of the tabs in sequence. Compared with the prior art, the welding size of the flattened tab area along the radial direction of the main body can be increased without increasing or increasing the flattened tab area, thereby reducing the transmission distance of electrons, reducing the internal resistance and polarization of the battery, and improving the performance of the battery;

[0030] (2) In the cylindrical electrode assembly described in the utility model, in the first to N layers of pole ears, the height difference between two adjacent layers of pole ears is equal to the distance between two adjacent layers of pole ears along the radial direction of the main body. After the pole ears are flattened, the second ends of the first to N-1 layers of pole ears are flush with the second end of the Nth layer of pole ears. Without increasing the flattened pole ear area, the welding size of the flattened pole ear area along the radial direction of the main body can be increased;

[0031] (3) The cylindrical electrode assembly of the utility model, from the position of the second end of the first layer of pole lugs after falling over to the position of the second end of the Mth layer of pole lugs, the number of pole lug layers in this area can ensure the welding effect;

[0032] (4) The cylindrical electrode assembly of the utility model has a significantly increased weldable size of the flattened tab area compared to the prior art by setting the flattened tab area with the required number of layers as a weldable area;

[0033] (5) The cylindrical electrode assembly described in the utility model has multiple layers of pole ears in the same pole ear part, which are tilted toward the center side of the main body part. The flattened pole ear area is in the shape of a fan ring concentric with the main body part. The edges of different pole ear sheets in the same layer of pole ears overlap to a certain extent. The second end of the pole ear is in a gathered shape, and the stacking is more dense, which further optimizes the welding performance of the flattened pole ear area.

[0034] (6) The cylindrical electrode assembly described in the utility model sets the acute angle of the parallelogram-shaped electrode tab in the prior art as a rounded angle, which can prevent the electrode tab from turning inward and reduce folding, so that the electrode tab flattening effect is better;

[0035] (7) In the cylindrical electrode assembly of the utility model, the plurality of tabs are formed by cutting a single-layer tab slit, which facilitates the connection and forming of the tabs;

[0036] (8) The cylindrical electrode assembly of the utility model has a through hole at the center of the main body, and the distance between the flattened electrode ear area and the through hole is greater than zero, which can ensure that different electrode ears do not contact each other;

[0037] (9) The cylindrical electrode assembly of the utility model comprises a main body including a first electrode piece, a second electrode piece, a first diaphragm and a second diaphragm. After the main body is wound, the first electrode piece and the second electrode piece are separated by the first diaphragm and the second diaphragm, so that the first electrode piece and the second electrode piece do not contact each other, thereby preventing a short circuit inside the main body;

[0038] (10) The cylindrical electrode assembly described in the utility model includes two pole ear parts, and the two pole ear parts are evenly distributed at the same end of the main body, which will not cause waste of space. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments of the utility model in combination with the accompanying drawings.

[0040] Figure 1 It is a schematic diagram of a cylindrical electrode assembly disclosed in the utility model;

[0041] Figure 2A schematic diagram of stacking multiple layers of pole ears on the same pole ear portion disclosed in the utility model;

[0042] Figure 3 It is a schematic diagram of splicing multiple tabs of the same layer of tabs disclosed in the utility model.

[0043] Explanation of the reference numerals in the specification: 1. main body; 11. through hole; 2. ear portion; 21. ear; 211. first end portion; 212. second end portion; 213. ear piece; 2131. first side edge; 2132. second side edge; 2133. third side edge; 2134. fourth side edge; 31. position A; 32. position B; 33. position C; 34. position D; 35. position E. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0045] Embodiment 1

[0046] See also Figure 1 to Figure 2 As shown, an embodiment of the cylindrical electrode assembly in the utility model.

[0047] The cylindrical electrode assembly comprises a main body 1 and a pole ear 2, wherein the main body 1 is wound into a cylindrical shape, the pole ear 2 is connected to the end of the main body, the pole ear 2 comprises multiple layers of pole ears 21, each layer of the pole ears 21 has a first end 211 and a second end 212 at its height, the first end 211 of each layer of the pole ears 21 is connected to the main body 1, the multiple layers of pole ears 21 of the same pole ear 2 are stacked in sequence, and the first ends 211 of the multiple layers of pole ears 21 of the same pole ear are stacked in sequence along the radial direction of the main body, and the multiple layers of pole ears 21 of the same pole ear 2 are collapsed toward the center side of the main body to form a flattened pole ear area;

[0048] When the multi-layer pole ears 21 of the same pole ear portion 2 fall toward the center side of the above-mentioned main body portion, in the multi-layer pole ears 21 stacked in sequence along the radial direction of the main body portion away from the center of the above-mentioned main body portion, the heights of the 1st to Nth layers of the pole ears 21 gradually increase, and the heights of the Nth to Mth layers of the pole ears 21 are the same, N is a positive integer greater than 1, and M is a positive integer greater than N.

[0049] The pole ear 21 of the above-mentioned cylindrical electrode assembly can be erected at the end of the main body or inverted at the end of the main body. When the pole ear 21 is erected at the end of the main body, the height direction of the pole ear 21 is consistent with the axial direction of the main body or is slightly deviated, the length direction of the pole ear 21 is consistent with the circumferential direction of the main body or is slightly deviated, and the thickness direction of the pole ear 21 is consistent with the radial direction of the main body or is slightly deviated. When the pole ear 21 is inverted at the end of the main body, the height of the pole ear 21 is consistent with the radial direction of the main body or is slightly deviated, the length direction of the pole ear 21 is consistent with the circumferential direction of the main body or is slightly deviated, and the thickness direction of the pole ear 21 is consistent with the axial direction of the main body or is slightly deviated.

[0050] The pole lug 21 falls toward the center side of the main body 1, which means that before and after the pole lug 21 falls, the position of the first end of the pole lug 21 relative to the main body 1 remains unchanged, before the falling, the surface of the pole lug 21 is parallel to or slightly deflected from the axial direction of the main body, after the falling, the surface of the pole lug 21 forms an angle with the axial direction of the main body, and in the same pole lug, the distance between the first end of each layer of the pole lug 21 and the center of the main body is greater than the distance between the second end of the pole lug 21 and the center of the main body. The distance between the first end and the second end of each layer of the pole lug 21 is the height dimension of the pole lug 21.

[0051] The pole ear part in the prior art includes the above-mentioned N to M layers of pole ears, excluding the above-mentioned 1 to N-1 layers of pole ears. The flattened pole ear area of ​​the pole ear part in the prior art is the area between the position of the second end of the Nth layer of pole ears after falling down and the position of the first end of the Mth layer of pole ears. Since the number of pole ear layers in the area between the first end and the second end of the Nth layer of pole ears after falling down does not meet the welding requirements, and the number of pole ear layers in the area between the first end and the second end of the Mth layer of pole ears after falling down also does not meet the welding requirements, therefore, the weldable area of ​​the pole ear part in the prior art is the area between the position of the first end of the Nth layer of pole ears and the position of the second end of the Mth layer of pole ears after falling down. That is to say, measured along the radial direction of the main body, the weldable area is smaller than the flattened pole ear area by the height of two layers of pole ears.

[0052] The pole ear portion in the present invention also includes the 1st to N-1 layers of pole ears 21, and the heights of the 1st to N-1 layers of pole ears 21 gradually increase. On the one hand, by increasing the 1st to N-1 layers of pole ears 21, the number of pole ear layers in at least a partial area between the first end 211 and the second end 212 of the Nth layer of pole ears 21 after falling over can meet the welding requirements, thereby increasing the size of the weldable area of ​​the flattened pole ear area. On the other hand, since the heights of the 1st to N-1 layers of pole ears 21 gradually decrease, the size of the flattened pole ear area along the radial direction of the main body can be kept from increasing or increased as little as possible.

[0053] Through the above technical solution: when the flattened tab area does not increase or increases slightly, the size of the weldable area is increased, the transmission distance of electrons is reduced, the internal resistance and polarization of the battery are reduced, and the performance of the battery is improved.

[0054] In this embodiment, in the multiple layers of pole lugs 21 of the same pole lug portion 2, in the first to Nth layers of pole lugs 21, the height difference between two adjacent layers of pole lugs 21 is equal to the distance between two adjacent layers of pole lugs 21 along the radial direction of the main body.

[0055] The distance between the two adjacent layers of the tabs 21 is equal to the thickness of two layers of separator + the thickness of the positive electrode sheet + the thickness of the negative electrode active coating on the opposite sides of the two adjacent negative electrode sheets. After the tabs 2 are flattened, the second end portions 212 of the tabs 21 of the 1st to N-1st layers can be substantially flush with the second end portion 212 of the tab 21 of the Nth layer.

[0056] Through the above technical solution: compared with the existing design, the length of the weldable area of ​​the flattened lug area along the radial direction of the main body can be increased without increasing the lug flattened area.

[0057] In this embodiment, the second end of the first layer of the pole ear 21 after lodging is located at position A31, the first end of the first layer of the pole ear 21 after lodging is located at position B32, the first end of the Nth layer of the pole ear 21 after lodging is located at position C33, the second end of the Mth layer of the pole ear 21 after lodging is located at position D34, and the first end of the Mth layer of the pole ear 21 after lodging is located at position E35;

[0058] The dimension of the flattened tab area measured along the axial direction of the main body is the thickness of the flattened tab area;

[0059] The thickness of the flattened lug region at the position A31 is δ1; the thickness of the flattened lug region at the position B32 is δ2; the thickness of the flattened lug region at the position C33 is δ3; the thickness of the flattened lug region at the position D34 is δ4;

[0060] δ1=T*(n+X1 / d); δ2=T*(n+2X1 / d); δ3=T*(n+X1 / d); δ4=T*(n+X1 / d);

[0061] Wherein, T is the thickness of each layer of tab;

[0062] n = N-1;

[0063] d is the distance between two adjacent layers of the pole lugs 21 along the radial direction of the main body;

[0064] X1 is the height of the first layer of tabs;

[0065] The thickness of the flattened lug area between the above-mentioned position A31 and the above-mentioned position B32 gradually increases, the thickness of the flattened lug area between the above-mentioned position B32 and the above-mentioned position C33 gradually decreases, the thickness of the flattened lug area between the above-mentioned position C33 and the above-mentioned position D34 is the same, and the thickness of the flattened lug area between the above-mentioned position D34 and the above-mentioned position E35 gradually decreases.

[0066] The flattened pole ear area of ​​the above-mentioned pole ear portion is the area between the position of the second end 212 of the Nth layer of pole ear 21 after lying down and the position of the first end 211 of the Mth layer of pole ear 21. The number of pole ear layers in the area between the position of the second end 212 of the Nth layer of pole ear 21 after lying down and the position of the second end 212 of the Mth layer of pole ear 21 after lying down is relatively large, all of which can meet the welding requirements, and the weldable area can be set to a larger size.

[0067] Through the above technical solution: from the position of the second end 212 of the first layer of pole tabs 21 after falling over to the position of the second end 212 of the Mth layer of pole tabs 21, the number of pole tab layers in this area can ensure the welding effect.

[0068] In this embodiment, the weldable dimension of the flattened tab area measured along the radial direction of the main body is L; L = R - R0 - Xn;

[0069] Wherein, R is the radius of the main body;

[0070] R0 is the distance between the position A of the flattened tab area and the center of the main body;

[0071] Xn is the height of the n-th layer of the tabs.

[0072] The flattened lug area of ​​the lug portion 2 is the area between the position of the second end 212 of the Nth layer of lug 21 after falling down and the position of the first end 211 of the Mth layer of lug 21, and the weldable area of ​​the lug portion 2 is the area between the position of the second end 212 of the Nth layer of lug 21 after falling down and the position of the second end 212 of the Mth layer of lug 21 after falling down. That is to say, measured along the radial direction of the main body, the weldable area is smaller than the flattened lug area by the height of one lug 21.

[0073] The following calculation is based on a cylindrical battery as an example:

[0074] Preferably R=22mm, R0=4mm, X1=3mm, d=0.2mm, Xn=R1+R2=6mm, n=15, R2=3mm; R3=12mm.

[0075] The weldable dimension of the flattened tab area in the prior art is L=R-R0-2Xn=6mm.

[0076] The weldable dimension of the flattened tab area in the utility model is L=R-R0-Xn=12mm;

[0077] Through the above technical solution: the weldable size of the flattened tab area is greatly increased compared with the weldable size of the flattened tab area in the prior art.

[0078] In this embodiment, the multi-layered pole lugs 21 of the same pole lug portion 2 fall down toward the center side of the main body portion, and the flattened pole lug area is in a fan-shaped ring concentric with the main body portion.

[0079] The tabs 21 are tilted toward the center of the main body, and the second ends 212 of the tabs 21 are stacked and gathered. The second ends 212 of the tabs 21 are stacked more densely.

[0080] Through the above technical solution: the welding performance of the flattened lug area is further optimized.

[0081] In this embodiment, each layer of the above-mentioned pole ear 21 includes a plurality of pole ear pieces 213 arranged in sequence along the length direction thereof, and the above-mentioned pole ear piece 213 has a first side 2131 and a second side 2132 in the height direction thereof, and the above-mentioned first side 2131 is connected to the above-mentioned main body 1, and the above-mentioned pole ear piece 213 has a third side 2133 and a fourth side 2134 in the length direction thereof, and the above-mentioned third side 2133 is connected to one end of the above-mentioned second side 2132 through an arc angle transition and / or the above-mentioned fourth side 2134 is connected to the other end of the above-mentioned second side 2132 through an arc angle transition.

[0082] The pole ear piece in the prior art is a parallelogram, and generally the second side 2132 is parallel to the first side 2131, and the two ends of the third side 2133 are respectively connected to the first side 2131 and one end of the second side 2132, and the angle between the third side 2133 and the second side 2132 is an obtuse angle, and the fourth side 2134 is parallel to the third side 2133, and the two ends of the fourth side 2134 are respectively connected to the first side 2133 and the other end of the second side. The acute angle area of ​​each parallelogram is very easy to shrink and turn inward due to the rapid heat dissipation, resulting in poor flattening effect of the pole ear. In the utility model, the fourth side 2134 is connected to the second side 2132 through an arc angle, and the acute angle of the pole ear piece 213 is cut into a rounded corner. In other embodiments, the third side is connected to the second side through an arc angle.

[0083] Through the above technical solution: the inward turning of the tab can be avoided, the folding can be reduced, and the tab flattening effect can be better.

[0084] In this embodiment, the plurality of electrode tab sheets 213 are formed by slit cutting of a single layer of electrode tabs 21 .

[0085] Specifically, the multiple tab sheets 213 of each layer of the tab 21 are formed by laser cutting the same tab. The tab cutting can be achieved by a laser cutting and winding machine. According to the winding flattening model of the positive and negative tabs on the same side, the length of the tabs of each circle of the winding core can be calculated for laser cutting. After confirming the length of each circle of the tabs, the height of the tabs can also be cut by laser cutting. According to this tab increment algorithm, the specific height value of each circle of the tabs can be given for laser cutting, thereby realizing the gradual change of the height of the tabs.

[0086] The above technical solution facilitates the connection and molding of the pole tab 213 .

[0087] In this embodiment, a through hole 11 is provided at the center of the main body along its axial direction, and a preset distance R0 is provided between the position A of the flattened tab area and the through hole 11 .

[0088] The main body 1 is wound around a central axis. After the winding is completed, the central axis needs to be separated from the main body 1. At this time, the through hole 11 is formed. The distance between the flattened pole ear area and the through hole 11 is greater than zero, which can ensure that different pole ear parts 2 are spaced a certain distance apart.

[0089] Through the above technical solution: it is ensured that different pole lugs 2 will not contact each other.

[0090] In this embodiment, the main body 1 includes a first pole piece, a first diaphragm, a second pole piece and a second diaphragm stacked in sequence. Among the first pole piece and the second pole piece, one is a positive pole piece and the other is a negative pole piece.

[0091] The positive electrode sheet and the negative electrode sheet are provided with a coating area, the coating area of ​​the positive electrode sheet is coated with positive electrode active material, and the coating area of ​​the negative electrode sheet is coated with negative electrode active material; connected to the coating area is a foil area, the foil area is copper foil or aluminum foil, and connected to the foil area is a tab area, the tab area is aluminum foil or copper foil. Among them, the aluminum foil (tab) is connected to the positive electrode sheet, and the copper foil (tab) is connected to the negative electrode sheet.

[0092] Through the above technical solution: it is ensured that the first pole piece and the second pole piece will not contact each other, thereby preventing a short circuit inside the main body 1.

[0093] In this embodiment, the cylindrical electrode assembly includes the two pole ear portions 2, which are evenly distributed at the same end of the main body. Among the two pole ear portions 2, one is the positive pole ear portion, and the other is the negative pole ear portion.

[0094] The positive electrode ear portion and the negative electrode ear portion are led out from the same end portion of the main body portion, and are respectively located at two eccentric positions of the end portion of the main body portion, and are generally symmetrically arranged.

[0095] Through the above technical solution: no waste of space will be caused.

[0096] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention of the utility model.

Claims

1. A cylindrical electrode assembly, characterized in that: The invention comprises a main body (1) and a pole ear (2), wherein the main body (1) is wound into a cylindrical shape, the pole ear (2) is connected to the end of the main body, the pole ear (2) comprises multiple layers of pole ears (21), each layer of the pole ears (21) has a first end (211) and a second end (212) in the height direction, the first end (211) is connected to the main body (1), the multiple layers of pole ears (21) of the same pole ear (2) are stacked in sequence, and the first ends (211) of the multiple layers of pole ears (21) of the same pole ear (2) are arranged in sequence along the radial direction of the main body, and the multiple layers of pole ears (21) of the same pole ear (2) are collapsed toward the center side of the main body to form a flattened pole ear area; In the multiple layers of pole ears (21) stacked in sequence along the radial direction of the main body away from the center of the main body, the heights of the pole ears (21) of the first to Nth layers gradually increase, and the heights of the pole ears (21) of the Nth to Mth layers are the same; Wherein, N is a positive integer greater than 1, and M is a positive integer greater than N.

2. The cylindrical electrode assembly according to claim 1, characterized in that: In the multiple layers of pole lugs (21) of the same pole lug portion (2), in the first to Nth layers of pole lugs (21), the height difference between two adjacent layers of pole lugs (21) is equal to the distance between two adjacent layers of pole lugs (21) along the radial direction of the main body portion.

3. The cylindrical electrode assembly according to claim 2, characterized in that: After lodging, the second end (212) of the first layer of the pole lug (21) is located at position A (31), the first end (211) of the first layer of the pole lug (21) is located at position B (32), the first end (211) of the Nth layer of the pole lug (21) is located at position C (33), the second end (212) of the Mth layer of the pole lug (21) is located at position D (34), and the first end (211) of the Mth layer of the pole lug (21) is located at position E (35); The dimension of the flattened tab area measured along the axial direction of the main body is the thickness of the flattened tab area; The thickness of the flattened lug region at the position A (31) is δ1; the thickness of the flattened lug region at the position B (32) is δ2; the thickness of the flattened lug region at the position C (33) is δ3; the thickness of the flattened lug region at the position D (34) is δ4; δ1=T*(n+X1 / d); δ2=T*(n+2X1 / d); δ3=T*(n+X1 / d); δ4=T*(n+X1 / d); Wherein, T is the thickness of each layer of tab; n=N-1; d is the distance between two adjacent layers of the pole lugs (21) along the radial direction of the main body; X1 is the height of the first layer of tabs; The thickness of the flattened lug area between the position A (31) and the position B (32) gradually increases, the thickness of the flattened lug area between the position B (32) and the position C (33) gradually decreases, the thickness of the flattened lug area between the position C (33) and the position D (34) is the same, and the thickness of the flattened lug area between the position D (34) and the position E (35) gradually decreases.

4. The cylindrical electrode assembly according to claim 3, characterized in that: The weldable dimension of the flattened tab area measured along the radial direction of the main body is L; L=R-R0-Xn; Wherein, R is the radius of the main body; R0 is the distance between the position A (31) of the flattened tab area and the center of the main body; Xn is the height of the tabs in the nth layer.

5. The cylindrical electrode assembly according to claim 1, characterized in that: The pole lugs fall down toward the center side of the main body, and the flattened pole lug area is in a fan ring shape concentric with the main body.

6. The cylindrical electrode assembly according to claim 1, characterized in that: Each layer of the pole lug (21) comprises a plurality of pole lug sheets (213) arranged in sequence along the length direction thereof, each pole lug sheet (213) having a first side edge (2131) and a second side edge (2132) in the height direction, the first side edge (2131) being connected to the main body (1), and each pole lug sheet (213) having a third side edge (2133) and a fourth side edge (2134) in the length direction, one end of the third side edge (2133) being connected to one end of the second side edge (2132) via an arc angle transition and / or one end of the fourth side edge (2134) being connected to the other end of the second side edge (2132) via an arc angle transition.

7. The cylindrical electrode assembly according to claim 6, characterized in that: The plurality of pole tab sheets (213) are formed by slit cutting of a single layer of pole tabs (21).

8. The cylindrical electrode assembly according to claim 1, characterized in that: A through hole (11) is provided at the center of the main body along its axial direction, and a preset distance R0 is provided between the position A (31) of the flattening lug area and the through hole (11).

9. The cylindrical electrode assembly according to claim 1, characterized in that: The main body (1) comprises a first pole piece, a first diaphragm, a second pole piece and a second diaphragm which are stacked in sequence, wherein one of the first pole piece and the second pole piece is a positive pole piece and the other is a negative pole piece.

10. The cylindrical electrode assembly according to claim 1, characterized in that: The cylindrical electrode assembly comprises two pole ear portions (2), the two pole ear portions (2) are evenly distributed at the same end of the main body portion, and one of the two pole ear portions (2) is a positive pole ear portion and the other is a negative pole ear portion.

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