A cylindrical battery and a manufacturing method thereof

Abstract

This invention proposes a cylindrical battery and its manufacturing method, comprising a positive electrode current collector, a negative electrode current collector, and a core. One end of the core is provided with a positive electrode tab group and a negative electrode tab group. The positive electrode tab group includes multiple positive electrode tab clusters, and the negative electrode tab group includes multiple negative electrode tab clusters. Both the positive and negative electrode tab clusters are distributed in a stepped manner from the outer radial direction of the core towards the center, and both clusters are concentric arc structures. The outer wall of the positive electrode current collector is provided with multiple positive electrode soldering areas, which are adapted to and connected to the arc-shaped inner wall of the positive electrode tab clusters. The outer wall of the negative electrode current collector is provided with multiple negative electrode soldering areas, which are adapted to and connected to the arc-shaped inner wall of the negative electrode tab clusters. In this invention, the current collector and tabs are vertically welded, avoiding the covering of gaps between electrode sheets after the tabs are flattened. This facilitates the penetration of electrolyte into the core from non-tab areas, improving the wetting efficiency of the electrolyte within the core.

Description

Technical Field

[0001] This invention relates to the field of cylindrical battery technology, and more particularly to a cylindrical battery and its manufacturing method. Background Technology

[0002] Currently, cylindrical batteries generally use positive and negative tabs at both ends. This structure means that after the positive and negative tabs at both ends of the core are flattened, they occupy part of the thickness of the core, reducing the space utilization of the core in the axial direction of the battery casing, thereby reducing the energy density of the cylindrical battery.

[0003] To improve battery energy density, some cylindrical batteries on the market have adopted a design where positive and negative tabs are located at one end. For example, Chinese patent CN112542641B discloses a cylindrical battery and its manufacturing method. The positive and negative tabs are placed on one end face of the core, the casing is set to be open at one end, and the core is sealed in the casing by a cover plate assembly. This improves the axial space utilization of the core in the casing, thereby increasing the energy density of the cylindrical battery.

[0004] The cylindrical battery disclosed above is manufactured by combining laser cutting with subsequent welding and flattening processes to form a positive and negative tab area at one end of the core formed by winding the positive and negative electrode sheets. The positive current collector and positive tab area are then flattened and welded together, and the negative current collector and negative tab area are flattened and welded together. Although the cylindrical battery disclosed in the patent can improve the axial space utilization of the core, the tabs cover the gaps between the electrode sheets after being flattened, making electrolyte wetting difficult during the electrolyte injection process as the electrolyte can only seep through the central column. Summary of the Invention

[0005] In view of this, the present invention proposes a cylindrical battery and its manufacturing method to solve the problem of difficulty in electrolyte wetting during injection when the positive and negative electrode tabs are produced at the same end of the core and the flattening process and current collector welding are used in the prior art.

[0006] The technical solution of this invention is implemented as follows:

[0007] On one hand, the present invention provides a cylindrical battery, which includes a positive current collector, a negative current collector, and a winding core;

[0008] One end of the winding core is provided with a first region and a second region, the first region is provided with a positive electrode tab group, and the second region is provided with a negative electrode tab group;

[0009] The positive electrode lug assembly includes multiple positive electrode lugs arranged along the axial direction of the core. The multiple positive electrode lugs are distributed in a stepped manner from the outer side of the core in the radial direction to the center of the core, and the multiple positive electrode lugs are concentric arc structures.

[0010] The positive current collector is horizontally arranged in the first region, and multiple positive current bonding areas are provided on the outer wall of the positive current collector. The positive current bonding areas are adapted to and connected to the arc-shaped inner wall of the positive current lug.

[0011] The negative electrode lug assembly includes multiple negative electrode lugs arranged along the axial direction of the core. The multiple negative electrode lugs are distributed in a stepped manner from the outer side of the core in the radial direction to the center of the core, and the multiple negative electrode lugs are concentric arc structures.

[0012] The negative electrode current collector is horizontally arranged in the second region. Multiple negative electrode soldering areas are provided on the outer wall of the negative electrode current collector. The negative electrode soldering areas are adapted to and connected to the arc-shaped inner wall of the negative electrode ear cluster.

[0013] Based on the above technical solution, preferably, the negative electrode lug group and the positive electrode lug group are arranged symmetrically with respect to the central axis of the winding core.

[0014] Furthermore, preferably, the positive electrode tab cluster is formed by stacking at least one positive electrode tab arranged vertically along the axial direction of the core, and the negative electrode tab cluster is formed by stacking at least one negative electrode tab arranged vertically along the axial direction of the core.

[0015] Furthermore, preferably, the thickness of each of the positive electrode tab clusters along the radial direction of the core is equal, and the thickness of each of the negative electrode tab clusters along the radial direction of the core is equal.

[0016] Preferably, the thickness of the positive electrode tab assembly is less than or equal to the thickness of the positive electrode current collector, and the thickness of the negative electrode tab assembly is less than or equal to the thickness of the negative electrode current collector.

[0017] Based on the above technical solution, preferably, the cylindrical battery further includes a housing and a cover plate assembly. The winding core is disposed in the housing. The cover plate assembly includes a cover plate, a positive electrode post, and a negative electrode post. The positive electrode post and the negative electrode post are fixedly disposed on the cover plate at intervals and are electrically isolated from the cover plate. The cover plate is provided with a liquid injection hole. The side of the positive electrode current collector away from the winding core is connected to the positive electrode post, and the side of the negative electrode current collector away from the winding core is connected to the negative electrode post. The cover plate is fixedly disposed at the opening end of the housing.

[0018] Furthermore, preferably, the cover plate assembly further includes a lower insulating member and a first connecting piece and a second connecting piece of a flexible structure. The lower insulating member is disposed on the bottom surface of the cover plate. One end of the first connecting piece is fixedly connected to the positive electrode post and the other end is fixedly connected to the positive electrode current collector. One end of the second connecting piece is fixedly connected to the negative electrode post and the other end is fixedly connected to the negative electrode current collector.

[0019] Furthermore, preferably, the cover plate assembly further includes a liquid equalization box, which is horizontally fixed on the bottom surface of the lower insulating member, with the liquid injection hole located at the center of the cover plate, and a plurality of liquid permeation holes provided on the liquid equalization box.

[0020] Preferably, both the positive electrode collector and the negative electrode collector are provided with several liquid passages.

[0021] On the other hand, the present invention also discloses a method for manufacturing a cylindrical battery, comprising the following steps:

[0022] S1. Cut out tabs with different spacings on the positive and negative electrode sheets respectively, and wind the positive and negative electrode sheets and the separator to form a core with positive and negative tabs on the same end, and make the wound negative tab group and positive tab group symmetrically arranged with respect to the central axis of the core.

[0023] S2. Place the positive current collector horizontally in the first area at one end of the core, and make the welding area on the outside of the positive current collector fit with the inner arc of the positive current collector lug. Weld the positive current collector lug and the positive current collector together from the outer arc of the positive current collector lug.

[0024] S3. Place the negative electrode current collector horizontally in the second area at one end of the core, and make the welding area on the outside of the negative electrode current collector fit with the inner arc of the negative electrode lug. Weld the negative electrode lug and the negative electrode current collector from the outer arc of the negative electrode lug.

[0025] S4. Weld one end of the first connecting piece to the surface of the positive current collector and fix the other end to the positive terminal post. Weld one end of the second connecting piece to the surface of the negative current collector and fix the other end to the negative terminal post.

[0026] S5. Place the core into the casing and seal it with the cover plate to complete the production of the cylindrical battery.

[0027] The present invention has the following advantages over the prior art:

[0028] (1) The cylindrical battery disclosed in this invention, by setting a positive electrode tab group and a negative electrode tab group at the same end of the winding core, by setting the positive electrode tab group as multiple positive electrode tab clusters distributed in a stepped manner from the outer side of the winding core in the radial direction towards the center of the winding core, and by setting the negative electrode tab group as multiple negative electrode tab clusters distributed in a stepped manner from the outer side of the winding core in the radial direction towards the center of the winding core, both the positive electrode tab clusters and the negative electrode tab clusters are arranged along the axial direction of the winding core, so that the positive electrode tabs and the negative electrode tabs are set vertically, by setting a positive electrode current collector and a negative electrode current collector, and by setting multiple positive electrode soldering areas on the outer wall of the positive electrode current collector, the positive electrode soldering areas are adapted to the arc-shaped inner wall of the positive electrode tab clusters, so that the positive electrode can be... The welding area on the outside of the current collector plate is in contact with the arc-shaped inner side of the positive electrode lug. The positive electrode lug and the positive current collector plate are welded together by the arc-shaped outer side of the positive electrode lug. The outer wall of the negative current collector plate is provided with multiple negative electrode welding areas. The negative electrode welding areas are adapted to the arc-shaped inner wall of the negative electrode lug. The welding area on the outside of the negative current collector plate is in contact with the arc-shaped inner side of the negative electrode lug. The negative electrode lug and the negative current collector plate are welded together by the arc-shaped outer side of the negative electrode lug. The current collector plate and the electrode lug are welded vertically to avoid the electrode lug covering the gap between the electrode sheets after it is flattened. This allows the electrolyte to penetrate into the core in the non-electrode lug area and improves the wetting efficiency of the electrolyte in the core.

[0029] (2) By distributing multiple positive electrode tabs in a stepped manner from the outer side of the core radially toward the center of the core, and distributing multiple negative electrode tabs in a stepped manner from the outer side of the core radially toward the center of the core, the first and second regions at the end can be equipped with electrode tabs from the outer side to the center of the core, thereby increasing the welding area between the electrode tabs and the current collector and improving the current carrying capacity of the electrode tabs and the current collector.

[0030] (3) By welding the electrode tab and the current collector together vertically, the welding quality can be controlled more intuitively, thus improving the welding quality between the electrode tab and the current collector.

[0031] (4) By setting the first and second connecting pieces with flexible structures, on the one hand, it is convenient to connect the pole post and the current collector after welding the current collector and the electrode tab, and the assembly is highly operable. On the other hand, after the current collector and the connecting piece are welded, they can be flexibly bent together. The bending process is simple, so as to ensure that the core and the cover plate are coaxial after bending, which is convenient for the battery to be installed in the casing.

[0032] (5) By setting up a liquid equalization box and opening several liquid permeation holes on the liquid equalization box, the electrolyte can flow to the surrounding area through the liquid equalization box after being injected through the liquid injection hole, and fall into various positions on the top surface of the core through the liquid permeation holes, thereby achieving that the electrolyte can penetrate into various positions of the core. At the same time, based on the non-flattening of the tabs, the wetting of the electrolyte in the core can be accelerated. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 effort.

[0034] Figure 1 This is a schematic diagram of the cylindrical battery structure disclosed in this invention;

[0035] Figure 2 This is a schematic diagram of the positive and negative current collector disks and the core assembly structure disclosed in this invention.

[0036] Figure 3 This is an exploded view of the positive and negative current collectors and the winding core disclosed in this invention;

[0037] Figure 4 This is a front perspective view of the cover plate assembly disclosed in this invention;

[0038] Figure 5 This is a three-dimensional structural diagram of the back of the cover plate assembly disclosed in this invention;

[0039] Figure 6 This is a top view of the cylindrical battery disclosed in this invention;

[0040] Figure 7 for Figure 6 Planar sectional view at point AA;

[0041] Figure 8 This is a three-dimensional structural diagram of the liquid equalization box disclosed in this invention;

[0042] Figure label:

[0043] 1. Positive current collector; 2. Negative current collector; 3. Core; P1, First region; P2, Second region; 31. Positive tab assembly; 32. Negative tab assembly; 310. Positive tab cluster; 320. Negative tab cluster; 11. Positive soldering area; 21. Negative soldering area; 4. Housing; 5. Cover plate assembly; 51. Cover plate; 52. Positive post; 53. Negative post; 511. Liquid injection hole; 54. Lower insulating component; 55. First connecting piece; 56. Second connecting piece; 57. Liquid equalization box; 570. Liquid permeation hole; S. Liquid passage. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] like Figure 1 As shown, combined with Figure 2-3 The present invention discloses a cylindrical battery, including a positive current collector 1, a negative current collector 2, and a core 3.

[0046] The core 3 is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator. One end of the core 3 has a first region P1 and a second region P2. The first region P1 is provided with a positive electrode tab group 31, and the second region P2 is provided with a negative electrode tab group 32. Specifically, both the positive electrode tab group 31 and the negative electrode tab group 32 are realized by a winding process.

[0047] In this embodiment, the first region P1 and the second region P2 are symmetrically arranged, thereby ensuring that the positive electrode tab group 31 and the negative electrode tab group 32 are evenly distributed at the end of the core 3.

[0048] In some related technologies, cylindrical batteries with tabs at the same end are manufactured by combining laser cutting with subsequent welding and flattening processes to form a positive and negative tab area at one end of the core 3 formed by winding the positive and negative electrode sheets. The positive current collector 1 and the positive tab area are then flattened and welded together, and the negative current collector 2 and the flattened negative tab area are welded together. Although the cylindrical battery disclosed in the aforementioned patent can improve the axial space utilization of the core 3, the tabs cover the gaps between the electrode sheets after being flattened, making electrolyte seepage only through the central column during the electrolyte injection process difficult.

[0049] Therefore, this embodiment has made structural arrangements for the above-mentioned positive electrode ear group 31 and negative electrode ear group 32.

[0050] In this embodiment, since the positive electrode tab group 31 and the negative electrode tab group 32 are located on both sides of the center of the core 3, in order to avoid covering the gaps between the electrode sheets due to the flattening process of the tabs, this embodiment sets the positive electrode tab group 31 as a plurality of positive electrode tab clusters 310 arranged along the axial direction of the core 3, so that the positive electrode tab clusters 310 are kept in an upright state. The positive electrode tab cluster 310 is formed by stacking at least one positive electrode tab arranged vertically along the axial direction of the core 3. Thus, the upright position of the positive electrode tabs can replace the flattening in the prior art.

[0051] To facilitate welding with the positive current collector 1, this embodiment arranges multiple positive electrode tab clusters 310 in a stepped manner from the outer radial direction of the core 3 towards the center of the core 3, and the multiple positive electrode tab clusters 310 have a concentric arc structure. This arrangement allows the multiple positive electrode tab clusters 310 to occupy a certain area in the first region P1, while reserving a non-tab area, which can be conveniently used to mount the positive current collector 1 for welding with the positive electrode tab group 31.

[0052] In order to achieve the welding of the positive current collector 1 and the positive tab group 31, in this embodiment, the positive current collector 1 is horizontally set in the first region P1. Specifically, the positive current collector 1 is located in the above-mentioned non-tab region. The outer wall of the positive current collector 1 is provided with multiple positive welding areas 11, and the positive welding areas 11 are adapted to and connected to the arc-shaped inner wall of the positive tab group 310.

[0053] With this configuration, during the actual assembly process, the welding area on the outside of the positive electrode current collector 1 and the arc-shaped inner side of the positive electrode lug 31 can be fitted together, and the arc-shaped outer side of the positive electrode lug 310 can be used to weld the positive electrode lug 310 and the positive electrode current collector 1.

[0054] Accordingly, in this embodiment, the negative electrode ear group 32 is configured as a plurality of negative electrode ear clusters 320 arranged along the axial direction of the core 3, so that the negative electrode ear clusters 320 are kept in an upright state, and the negative electrode ear clusters 320 are formed by stacking at least one negative electrode ear arranged vertically along the axial direction of the core 3. Thus, the negative electrode ear can be replaced by the flattening in the prior art by being upright.

[0055] To facilitate welding with the negative electrode current collector 2, this embodiment arranges multiple negative electrode tab clusters 320 in a stepped manner from the outer radial direction of the core 3 towards the center of the core 3, and the multiple negative electrode tab clusters 320 have a concentric arc structure. This arrangement allows the multiple negative electrode tab clusters 320 to occupy a certain area in the second region P2, while reserving a non-tab area, which can be conveniently used to mount the negative electrode current collector 2 for welding with the negative electrode tab clusters 32.

[0056] In order to achieve welding between the negative electrode current collector 2 and the negative electrode lug 32, in this embodiment, the negative electrode current collector 2 is horizontally set in the second region P2. Specifically, the negative electrode current collector 2 is located in the above-mentioned non-lever region. Multiple negative electrode welding areas 21 are provided on the outer wall of the negative electrode current collector 2. The negative electrode welding areas 21 are adapted to and connected to the arc-shaped inner wall of the negative electrode lug 320.

[0057] With this configuration, during the actual assembly process, the welding area on the outside of the negative electrode current collector 2 and the arc-shaped inner side of the negative electrode ear group 32 can be fitted together, and the arc-shaped outer side of the negative electrode ear cluster 320 can be used to weld the negative electrode ear cluster 320 and the negative electrode current collector 2.

[0058] By adopting the above technical solution, the positive electrode current collector 1, the negative electrode current collector 2 and the electrode tab are vertically welded, which avoids the electrode tab from covering the gap between the electrode sheets after being flattened. This allows the electrolyte to easily penetrate into the core 3 in the non-electrode tab area, thereby improving the wetting efficiency of the electrolyte in the core 3.

[0059] It is worth noting that by distributing multiple positive electrode tab clusters 310 in a stepped manner from the outer side of the core 3 in the radial direction towards the center of the core 3, and distributing multiple negative electrode tab clusters 320 in a stepped manner from the outer side of the core 3 in the radial direction towards the center of the core 3, the first region P1 and the second region P2 at the end can be distributed with electrode tabs from the outer side to the center of the core 3, thereby increasing the welding area between the electrode tabs and the current collector and improving the current carrying capacity of the electrode tabs and the current collector.

[0060] In this embodiment, the negative electrode lug group 32 and the positive electrode lug group 31 are symmetrically arranged with respect to the central axis of the core 3. In one implementation, the negative electrode lug group 32 and the positive electrode lug group 31 are symmetrical with respect to the central longitudinal section of the core 3. In another implementation, the negative electrode lug group 32 and the positive electrode lug group 31 are symmetrically arranged with respect to the center line of the core 3. This arrangement allows the non-electrode areas on the top surface of the core 3 to be staggered, enabling the electrolyte to be evenly wetted.

[0061] Preferably, the thickness of each positive electrode tab cluster 310 along the radial direction of the core 3 is equal, and the thickness of each negative electrode tab cluster 320 along the radial direction of the core 3 is equal. This configuration ensures that the process parameters for welding each positive electrode tab cluster 310 and the positive electrode soldering area 11 are consistent, and correspondingly, the process parameters for welding each negative electrode tab cluster 320 and the negative electrode soldering area 21 are consistent.

[0062] In some other embodiments, the thickness of the positive electrode tab assembly 31 is less than or equal to the thickness of the positive electrode current collector 1, and the thickness of the negative electrode tab assembly 32 is less than or equal to the thickness of the negative electrode current collector 2. This configuration allows the outer wall of the positive electrode current collector 1 to be fully welded to the positive electrode tab cluster 310, and the outer wall of the negative electrode current collector 2 to be fully welded to the negative electrode tab cluster 320, ensuring welding reliability.

[0063] Furthermore, it is worth noting that in this embodiment, the positive electrode tabs 310 are directly welded to the positive electrode welding area 11 on the outside of the positive current collector 1, and the negative electrode tabs 320 are welded to the negative electrode welding area 21 on the outside of the negative current collector. Compared with the prior art where the current collector is covered by the flattened top surface of the core 3 for laser penetration welding, this allows for more intuitive control of welding quality and facilitates welding quality inspection.

[0064] See attached document Figure 4-8As shown, the cylindrical battery of the present invention also includes a housing 4 and a cover plate assembly 5. The core 3 is disposed in the housing 4. The cover plate assembly 5 includes a cover plate 51, a positive electrode post 52 and a negative electrode post 53. The positive electrode post 52 and the negative electrode post 53 are fixedly disposed on the cover plate 51 at intervals and are electrically isolated from the cover plate 51. The cover plate 51 is provided with an injection hole 511. The side of the positive electrode current collector 1 away from the core 3 is connected to the positive electrode post 52, and the side of the negative electrode current collector 2 away from the core 3 is connected to the negative electrode post 53. The cover plate 51 is fixedly disposed at the opening end of the housing 4.

[0065] It should be noted that the positive terminal 52 and negative terminal 53 in this embodiment can be connected by riveting on the cover plate 51. This method is existing technology and will not be described in detail here.

[0066] In one implementation, after the current collector is welded to the tabs at the end of the winding core 3, to facilitate welding of the current collector to the electrode post on the cover plate 51, this embodiment also provides a first connecting piece 55 and a second connecting piece 56 with flexible structures. A lower insulating member 54 is also provided, disposed on the bottom surface of the cover plate 51, to isolate the current collector and the cover plate 51. One end of the first connecting piece 55 is fixedly connected to the positive electrode post 52, and the other end is fixedly connected to the positive current collector 1. One end of the second connecting piece 56 is fixedly connected to the negative electrode post 53, and the other end is fixedly connected to the negative current collector 2.

[0067] By setting the first connecting piece 55 and the second connecting piece 56 with flexible structures, on the one hand, it is convenient to connect the electrode post and the current collector after the current collector is welded to the electrode tab, and the assembly is highly operable. On the other hand, after the current collector and the connecting piece are welded, they can be flexibly bent together. The bending process is simple, so as to ensure that the core 3 and the cover plate 51 are coaxial after bending, which is convenient for the battery to be installed in the casing.

[0068] In this embodiment, the first connecting piece 55 and the second connecting piece 56 can be formed by stacking multiple layers of metal foil. On the one hand, they can serve as conductors, and on the other hand, they possess flexible properties, facilitating welding and bending.

[0069] To improve electrolyte wetting efficiency, the cover plate assembly 5 in this embodiment also includes a liquid distribution box 57. The liquid distribution box 57 is horizontally fixed on the bottom surface of the lower insulating member 54, and the injection hole 511 is located at the center of the cover plate 51. The liquid distribution box 57 is provided with a plurality of liquid permeation holes 570. With this configuration, after the electrolyte is injected through the injection hole 511, it can flow to the surrounding area through the liquid distribution box 57 and fall into various positions on the top surface of the core 3 through the liquid permeation holes 570, thereby achieving electrolyte penetration into various positions of the core 3. At the same time, based on the non-flattening of the tabs, the wetting of the electrolyte in the core 3 can be accelerated.

[0070] Since the positive electrode current collector 1 and the negative electrode current collector 2 are located in the non-tab area on the top surface of the core 3, in order to allow the electrolyte to penetrate into the core 3 through the non-tab area, this embodiment provides several liquid passage channels S on both the positive electrode current collector 1 and the negative electrode current collector 2. Therefore, after the injected electrolyte falls onto the current collector, it can enter the non-tab area through the liquid passage channels S, thereby penetrating into the core 3 and accelerating the wetting efficiency of the electrolyte in the core 3.

[0071] On the other hand, the present invention also discloses a method for manufacturing a cylindrical battery, comprising the following steps:

[0072] S1. Cut out tabs with different spacings on the positive and negative electrode sheets respectively, and wind the positive and negative electrode sheets and the separator to form a core 3 with the positive and negative tabs on the same end, and make the negative tab group 32 and the positive tab group 31 formed by winding symmetrically arranged with respect to the central axis of the core 3.

[0073] In this step, the positive electrode tabs and negative electrode tabs can be wound together by controlling the position of the tabs on the electrode sheet; or multiple positive electrode tabs can be wound on one half of the top surface of the core, and multiple negative electrode tabs can be wound on the other half of the top surface of the core, and then the positive electrode tabs and negative electrode tabs can be obtained by cutting.

[0074] S2. Place the positive current collector 1 horizontally in the first area P1 at one end of the core 3, and make the welding area on the outside of the positive current collector 1 fit with the arc-shaped inner side of the positive current collector 31. Weld the positive current collector 310 and the positive current collector 1 from the arc-shaped outer side of the positive current collector 310.

[0075] The positive electrode current collector can be obtained through cutting or other machining processes. In this embodiment, the multiple positive electrode soldering areas on the outer periphery of the positive electrode current collector are in a stepped arc shape, and are designed to match the inner wall contour of the positive electrode lug assembly.

[0076] S3. Place the negative electrode current collector 2 horizontally in the second area P2 at one end of the core 3, and make the welding area on the outside of the negative electrode current collector 2 fit with the arc-shaped inner side of the negative electrode ear group 32. Weld the negative electrode ear group 320 and the negative electrode current collector 2 from the arc-shaped outer side of the negative electrode ear group 320.

[0077] The negative electrode current collector can be obtained through cutting or other machining processes. In this embodiment, the multiple negative electrode welding areas on the outer periphery of the negative electrode current collector are in a stepped arc shape, and are designed to match the inner wall contour of the negative electrode lug assembly.

[0078] In the above steps, the welding between the tabs and the collector plate can be done by ultrasonic welding or laser welding. As some implementation methods, after the core is wound, the positive tab cluster 310 and the negative tab cluster 320 can be pre-welded with ultrasonic welding in advance, so that the positive tab cluster and the negative tab cluster are stacked vertically together. This makes it convenient for the collector plate to be placed on the top surface of the core, and then laser welding can be quickly performed on the outer side (welding area) of the collector plate through the arc-shaped outer side of the tab cluster. This avoids poor welding between the tab cluster and the outer side of the collector plate due to the tabs being too loose.

[0079] S4. Weld one end of the first connecting piece 55 to the surface of the positive current collector 1, and fix the other end to the positive terminal 52. Weld one end of the second connecting piece 56 to the surface of the negative current collector 2, and fix the other end to the negative terminal 53. The connecting pieces can be connected to the terminal by laser welding or by riveting.

[0080] S5. Place the core 3 into the housing 4 and seal it with the cover plate 51 to complete the production of the cylindrical battery.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cylindrical battery, comprising a positive current collector (1), a negative current collector (2), and a core (3); Its features are: One end of the core (3) is provided with a first region (P1) and a second region (P2), the first region (P1) is provided with a positive electrode tab group (31), and the second region (P2) is provided with a negative electrode tab group (32); The positive electrode ear group (31) includes multiple positive electrode ear clusters (310), which are distributed in a stepped manner from the outer radial direction of the core (3) towards the center of the core (3), and the multiple positive electrode ear clusters (310) are concentric arc structures; The positive current collector (1) is horizontally arranged in the first region (P1). Multiple positive current welding areas (11) are provided on the outer wall of the positive current collector (1). The positive current welding areas (11) are adapted to and connected to the arc-shaped inner wall of the positive current ear cluster (310). The negative electrode ear group (32) includes multiple negative electrode ear clusters (320), which are distributed in a stepped manner from the outer radial direction of the core (3) towards the center of the core (3), and the multiple negative electrode ear clusters (320) are concentric arc structures; The negative electrode current collector (2) is horizontally arranged in the second region (P2). Multiple negative electrode soldering areas (21) are provided on the outer wall of the negative electrode current collector (2). The negative electrode soldering areas (21) are adapted to and connected to the arc-shaped inner wall of the negative electrode ear cluster (320).

2. The cylindrical battery as described in claim 1, characterized in that: The negative electrode lug group (32) and the positive electrode lug group (31) are arranged symmetrically with respect to the central axis of the core (3).

3. The cylindrical battery as described in claim 2, characterized in that: The positive electrode ear cluster (310) is formed by stacking at least one positive electrode ear vertically arranged along the axial direction of the core (3), and the negative electrode ear cluster (320) is formed by stacking at least one negative electrode ear vertically arranged along the axial direction of the core (3).

4. The cylindrical battery as described in claim 3, characterized in that: The thickness of each positive electrode tab (310) along the radial direction of the core (3) is equal, and the thickness of each negative electrode tab (320) along the radial direction of the core (3) is equal.

5. The cylindrical battery as described in claim 1, characterized in that: The thickness of the positive electrode tab group (31) is less than or equal to the thickness of the positive electrode current collector (1), and the thickness of the negative electrode tab group (32) is less than or equal to the thickness of the negative electrode current collector (2).

6. The cylindrical battery as described in claim 1, characterized in that: The cylindrical battery also includes a housing (4) and a cover plate (51) assembly (5). The core (3) is disposed in the housing (4). The cover plate (51) assembly (5) includes a cover plate (51), a positive electrode post (52) and a negative electrode post (53). The positive electrode post (52) and the negative electrode post (53) are fixedly disposed on the cover plate (51) at intervals and are electrically isolated from the cover plate (51). The cover plate (51) is provided with an injection hole (511). The side of the positive electrode current collector (1) away from the core (3) is connected to the positive electrode post (52). The side of the negative electrode current collector (2) away from the core (3) is connected to the negative electrode post (53). The cover plate (51) is fixedly disposed at the opening end of the housing (4).

7. The cylindrical battery as described in claim 6, characterized in that: The cover plate (51) assembly (5) further includes a lower insulating member (54) and a first connecting piece (55) and a second connecting piece (56) of a flexible structure. The lower insulating member (54) is disposed on the bottom surface of the cover plate (51). One end of the first connecting piece (55) is fixedly connected to the positive electrode post (52) and the other end is fixedly connected to the positive electrode current collector (1). One end of the second connecting piece (56) is fixedly connected to the negative electrode post (53) and the other end is fixedly connected to the negative electrode current collector (2).

8. The cylindrical battery as described in claim 7, characterized in that: The cover plate (51) assembly (5) also includes a liquid equalization box (57), which is horizontally fixed on the bottom surface of the lower insulating member (54). The liquid injection hole (511) is located at the center of the cover plate (51), and the liquid equalization box (57) is provided with a plurality of liquid permeation holes (570).

9. The cylindrical battery as described in claim 1, characterized in that: Both the positive electrode collector (1) and the negative electrode collector (2) are provided with several liquid passages (S).

10. A method for manufacturing a cylindrical battery as described in claim 7, characterized in that, Includes the following steps: S1. Cut out tabs with different spacings on the positive and negative electrode sheets respectively, and wind the positive and negative electrode sheets and the separator to form a core (3) with the positive and negative tabs on the same end, and make the negative tab group (32) and the positive tab group (31) formed by winding symmetrically arranged with respect to the central axis of the core (3). S2. Place the positive current collector (1) horizontally in the first region (P1) at one end of the core (3), and make the welding area on the outside of the positive current collector (1) and the inner arc of the positive ear group (31) fit together. Weld the positive ear group (310) and the positive current collector (1) from the outer arc of the positive ear group (310). S3. Place the negative electrode current collector (2) horizontally in the second region (P2) at one end of the core (3), and make the welding area on the outside of the negative electrode current collector (2) and the arc-shaped inner side of the negative electrode ear group (32) fit together. Weld the negative electrode ear group (320) and the negative electrode current collector (2) by the arc-shaped outer side of the negative electrode ear group (320). S4. Weld one end of the first connecting piece (55) to the surface of the positive current collector (1) and fix the other end to the positive terminal post (52). Weld one end of the second connecting piece (56) to the surface of the negative current collector (2) and fix the other end to the negative terminal post (53). S5. Place the core (3) into the housing (4) and seal it with the opening of the housing (4) through the cover plate (51) to complete the production of the cylindrical battery.

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