A battery cover plate assembly, cylindrical battery and assembly process

Abstract

The application provides a battery cover plate assembly, a cylindrical battery and an assembling process, which comprises a cover plate, a positive pole and a negative pole, the positive pole and the negative pole are fixedly arranged on the cover plate at intervals and are electrically isolated from the cover plate, and further comprises a positive current collector and a negative current collector which are configured as flexible structures, one end of the positive current collector is fixedly connected with the positive pole, and the other end is welded with a positive pole lug on a roll core, one end of the negative current collector is fixedly connected with the negative pole, and the other end is welded with a negative pole lug on the roll core, the positive current collector and the negative current collector are both configured as flexible structures, the current collector can be flexibly bent after being welded with the pole lug, the bending process is simple, the coaxiality between the roll core and the cover plate after bending is high, the accuracy of battery shell can be ensured, the traditional current collector bending process is avoided to cause defective products, and the production efficiency and product quality of the cylindrical battery are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a battery cover assembly, a cylindrical battery, and an assembly process. 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. Furthermore, during assembly, the cylindrical battery is assembled by setting positive and negative current collectors. One end of the positive current collector is connected to the positive electrode post on the cover plate, and the other end is welded to the positive tab area. One end of the negative current collector is connected to the negative electrode post on the cover plate, and the other end is welded to the negative tab area. After the current collectors are welded to the core, they need to be bent twice to ensure the core and cover plate are coaxial before being inserted into the casing. Finally, the cover plate and casing are laser-welded around the perimeter to complete the battery assembly process.

[0005] However, when bending the positive and negative current collectors, the two bending points must be precise to ensure the accuracy of battery insertion into the casing. From the perspective of battery manufacturing, there are many points that need to be controlled during bending. If any one of these points deviates, the cover plate and the casing will not be coaxial, making it difficult to insert the battery into the casing later, thus increasing the defect rate of the bending process. Summary of the Invention

[0006] In view of this, the present invention proposes a battery cover assembly, a cylindrical battery, and an assembly process to solve the problem that in cylindrical batteries with positive and negative tabs at one end of the core, the bending process of the positive and negative current collectors has dimensional deviations, which leads to the cover and the casing not being coaxial, the accuracy of battery insertion into the casing cannot be guaranteed, and the bending process has a high defect rate.

[0007] The technical solution of this invention is implemented as follows:

[0008] In one aspect, the application provides a battery cover plate assembly, which comprises a cover plate, a positive pole and a negative pole, the positive pole and the negative pole are fixedly arranged on the cover plate and are electrically isolated from the cover plate;

[0009] The positive pole current collector and the negative pole current collector are configured as flexible structures;

[0010] One end of the positive pole current collector is fixedly connected with the positive pole, and the other end is welded with the positive pole lug on the winding core;

[0011] One end of the negative pole current collector is fixedly connected with the negative pole, and the other end is welded with the negative pole lug on the winding core;

[0012] When the cover plate approaches the end of the winding core, the positive pole current collector and the negative pole current collector are bent and compressed so that the cover plate covers the end of the winding core and is coaxially arranged.

[0013] On the basis of the above technical solution, preferably, the positive pole current collector and the negative pole current collector are both formed by stacking multiple layers of metal foil.

[0014] On the basis of the above technical solution, preferably, the battery cover plate assembly further comprises a first upper insulating piece, a second upper insulating piece, a lower insulating piece, a positive riveting piece and a negative riveting piece, the positive pole, the first upper insulating piece, the cover plate, the lower insulating piece and the positive pole current collector are sequentially fixedly connected through the positive riveting piece; the negative pole, the second upper insulating piece, the cover plate, the second lower insulating piece and the negative pole current collector are sequentially fixedly connected through the negative riveting piece.

[0015] Further, preferably, the bottom surface of the lower insulating piece is provided with an annular flange in contact with the end surface of the winding core.

[0016] Preferably, the positive pole current collector, the positive pole and the positive pole lug on the winding core are made of the same material, and the negative pole current collector, the negative pole and the negative pole lug on the winding core are made of the same material.

[0017] On the other hand, the application also provides a cylindrical battery, which comprises a shell, a winding core and the battery cover plate assembly, the winding core is formed by winding a positive pole sheet, a separator and a negative pole sheet, the winding core is arranged in the shell, a plurality of positive pole lugs of the positive pole sheet and a plurality of negative pole lugs of the negative pole sheet are located on the same end surface of the winding core, the plurality of positive pole lugs and the plurality of negative pole lugs are symmetrically distributed with respect to the center of the winding core, the plurality of positive pole lugs are stacked to form a positive pole lug cluster along the radial direction of the winding core, the plurality of negative pole lugs are stacked to form a negative pole lug cluster along the radial direction of the winding core, one end of the positive pole current collector away from the positive pole is welded with the positive pole lug cluster, one end of the negative pole current collector away from the negative pole is welded with the negative pole lug cluster, and the cover plate is fixedly connected with the open end of the shell.

[0018] On the basis of the above technical scheme, preferably, the height of the plurality of positive tabs gradually increases from the center of the positive tab cluster to both sides, and the height of the plurality of negative tabs gradually increases from the center of the negative tab cluster to both sides.

[0019] Further, preferably, one end surface of the positive current collector disc is provided with a first connecting hole connected with the positive riveting part, and the other end surface of the positive current collector disc is welded with the side surface of the positive tab cluster; one end surface of the negative current collector disc is provided with a second connecting hole connected with the negative riveting part, and the other end surface of the negative current collector disc is welded with the side surface of the negative tab cluster.

[0020] Preferably, the center of the cover plate is provided with a liquid injection hole, the positive column and the negative column are symmetrically arranged relative to the liquid injection hole, and the lower insulating part is provided with a through hole coaxial with the liquid injection hole at the center.

[0021] The application also provides an assembling process of the cylindrical battery, which comprises the following steps:

[0022] S1, cutting out positive and negative electrode sheets with different intervals and sizes;

[0023] S2, winding the positive and negative electrode sheets and the separator to form a winding core, and arranging the positive and negative tabs at the same end of the winding core and symmetrically distributing the positive and negative tabs relative to the center of the winding core;

[0024] S3, stacking a plurality of positive tabs along the radial direction of the winding core and pre-welding the positive tabs by ultrasonic wave to form a positive tab cluster, and stacking a plurality of negative tabs along the radial direction of the winding core and pre-welding the negative tabs by ultrasonic wave to form a negative tab cluster;

[0025] S4, ultrasonic welding one end surface of the positive current collector disc with the side surface of the positive tab cluster, and connecting the other end of the positive current collector disc with the positive column through the positive riveting part, ultrasonic welding one end surface of the negative current collector disc with the side surface of the negative tab cluster, and connecting the other end of the negative current collector disc with the negative column through the negative riveting part;

[0026] S5, placing the winding core into the shell, and closing and fixing the shell through the opening end of the cover plate to complete the assembly of the cylindrical battery.

[0027] The application has the following beneficial effects compared with the prior art:

[0028] (1) The battery cover plate assembly disclosed by the application sets the positive current collector disc and the negative current collector disc as flexible structures, the current collector disc can be flexibly bent after being welded with the tab, the bending process is simple, the coaxiality of the winding core and the cover plate after bending is high, the accuracy of the battery into the shell can be ensured, the traditional current collector disc bending process is avoided to cause defective products, and the production efficiency and product quality of the cylindrical battery are greatly improved.

[0029] (2) by making the positive and negative current collectors are formed by stacking multiple layers of metal foil, on the one hand, it can improve the overcurrent capacity of the cylindrical battery, on the other hand, the stacking of multiple layers of metal foil improves the structural strength of the positive and negative current collectors while not affecting their flexibility, which facilitates the flexible bending of the positive and negative current collectors and the positive and negative tabs after welding;

[0030] (3) by stacking a plurality of positive tabs along the radial direction of the winding core to form a positive tab cluster and a plurality of negative tabs along the radial direction of the winding core to form a negative tab cluster, since the positive and negative current collectors are flexible and the matching winding core multi-tab structure is also flexible, the current collectors and the tab clusters can be flexibly bent after welding, the bending process is simple, and thus the coaxiality of the winding core and the cover plate after bending can be ensured, which facilitates the battery into the shell;

[0031] (4) since the current collectors and the winding core tabs are both multiple-foil structures, the size, thickness and number of foils can be determined according to design needs, which can fully meet the overcurrent requirements of large cylindrical battery winding cores and cover plates, and is suitable for the design and use of large-capacity and large-rate cylindrical batteries, and the winding core tabs are on the same side, and the single-cover plate structure improves the space utilization of the winding core in the height direction, which is beneficial to improve the energy density of the battery;

[0032] (5) a plurality of positive tabs are stacked along the radial direction of the winding core and pre-welded by ultrasonic waves to form a positive tab cluster, which is welded with the flexible positive current collector, and a plurality of negative tabs are stacked along the radial direction of the winding core and pre-welded by ultrasonic waves to form a negative tab cluster, which is welded with the negative current collector, thereby canceling the rubbing and flattening process step of the full-tab winding core and simplifying the battery manufacturing process;

[0033] (6) the tabs on the end face of the winding core are not subjected to rubbing and flattening and are in a non-dense open structure, so that the electrolyte can more easily infiltrate the internal tabs of the battery during liquid injection, which can greatly reduce the liquid injection time of the battery and improve the production efficiency;

[0034] (7) the winding core is fixed by the contact and support of the annular flange on the bottom surface of the lower plastic part and the end face of the winding core, the bent tabs and current collectors are not subjected to extrusion force between the lower plastic part and the winding core, there is no risk of stress concentration leading to the fracture of the current collectors, and the safety performance of the battery is improved. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, a brief introduction will be given below to the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0036] Figure 1 It is a schematic diagram of the three-dimensional structure of the battery cover plate assembly disclosed by the present application.

[0037] Figure 2 This is a schematic diagram of the assembly structure of the battery cover plate assembly and the winding core disclosed in this invention;

[0038] Figure 3 This is an exploded view of the battery cover assembly disclosed in this invention;

[0039] Figure 4 This is a schematic diagram of the planar structure of the battery cover assembly disclosed in this invention;

[0040] Figure 5 This is a schematic diagram of the exploded structure of the cylindrical battery disclosed in this invention;

[0041] Figure 6 This is a schematic diagram of the structure of the core disclosed in this invention;

[0042] Figure 7 This is a schematic diagram of the planar structure of the cylindrical battery disclosed in this invention;

[0043] Figure label:

[0044] 1. Battery cover assembly; 11. Cover plate; 12. Positive terminal post; 13. Negative terminal post; 14. Positive current collector; 15. Negative current collector; 16. First upper insulator; 17. Second upper insulator; 18. Lower insulator; 19. Positive terminal riveting component; 20. Negative terminal riveting component; S. Sealing ring; 180. Annular flange; 2. Housing; 3. Core; 31a. Positive terminal tab; 32a. Negative terminal tab; 31. Positive terminal tab cluster; 32. Negative terminal tab cluster; 141. First connecting hole; 142. Second connecting hole; 110. Liquid injection hole; 181. Through hole. Detailed Implementation

[0045] 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.

[0046] like Figure 1 As shown, combined with Figures 2-4The battery cover plate assembly 1 comprises a cover plate 11, a positive pole 12 and a negative pole 13, the positive pole 12 and the negative pole 13 are fixedly arranged on the cover plate 11 and are electrically isolated from the cover plate 11. The battery cover plate assembly 1 further comprises a positive current collector 14 and a negative current collector 15, one end of the positive current collector 14 is fixedly connected with the positive pole 12, and the other end is welded with a positive pole lug 31a on a winding core 3; one end of the negative current collector 15 is fixedly connected with the negative pole 13, and the other end is welded with a negative pole lug 32a on the winding core 3. Through the same end of the winding core 3, the positive pole lug 31a and the negative pole lug 32a are arranged, on one hand, the cylindrical battery realizes double poles at the same end, on the other hand, the space utilization rate of the winding core 3 in the axial direction of the shell 2 is improved, and then the energy density of the cylindrical battery is improved.

[0047] As prior art, after the positive and negative pole lugs on the same side of the winding core 3 are connected with the positive and negative current collectors, the winding core 3 needs to be bent twice to make the winding core 3 and the cover plate 11 coaxial when the winding core 3 enters the shell, and finally the cover plate 11 and the shell 2 are laser periphery welded to complete the assembly process of the battery. However, when the positive and negative current collectors are bent, the two bending points must be accurate to ensure the accuracy of the battery entering the shell. From the perspective of battery manufacturing, many points need to be controlled during bending, and deviation of a certain point will cause the cover plate 11 and the shell 2 to be unable to be coaxial, which brings difficulty in subsequent battery entering the shell, thereby increasing the defective rate of the bending process.

[0048] Therefore, the positive current collector 14 and the negative current collector 15 are arranged in a flexible structure in the embodiment, so that the positive current collector 14 and the negative current collector 15 have the flexible feature, the current collector can be flexibly bent after being welded with the pole lug, the bending process is simple, the coaxial degree of the winding core 3 and the cover plate 11 after bending is high, the accuracy of the battery entering the shell can be ensured, the traditional current collector bending process is avoided to cause defective products, and the production efficiency and product quality of the cylindrical battery are greatly improved.

[0049] In order to make the positive current collector 14 and the negative current collector 15 have the flexible function and the conductive function, the positive current collector 14 and the negative current collector 15 in the embodiment are both arranged as metal foil materials, the foil material is relatively thin, preferably, the thickness of the foil material is substantially the same as that of the pole piece, so that the metal foil material has strong flexibility, and it is easier to bend after being welded with the pole lug.

[0050] However, since the metal foil material is selected as the positive current collector 14 and the negative current collector 15, the positive and negative current collectors are relatively thin, on one hand, the current capacity is small, on the other hand, the structural strength of the positive and negative current collectors is weak, and the positive and negative current collectors are easily broken during welding, thereby causing poor safety and stability.

[0051] To this end, the positive current collector 14 and the negative current collector 15 are both formed by stacking multiple layers of metal foils, which can improve the overcurrent capacity of the cylindrical battery and also improve the structural strength of the positive and negative current collectors while maintaining their flexibility for bending after welding.

[0052] In the present embodiment, the positive current collector 14 and the negative current collector 15 are formed by stacking multiple layers of metal foils and then welding them together using ultrasonic waves, which can improve the overcurrent capacity while also achieving flexible bending and meeting the structural strength requirements.

[0053] It is worth noting that the overall thickness of the positive current collector 14 and the negative current collector 15 can be adjusted according to the thickness of each layer of foil and the number of layers to meet the overcurrent requirements of the battery cover plate 11.

[0054] In the present embodiment, the battery cover plate assembly 1 further includes a first upper insulating member 16, a second upper insulating member 17, a lower insulating member 18, a positive riveting member 19, and a negative riveting member 20. The positive post 12, the first upper insulating member 16, the cover plate 11, the lower insulating member 18, and the positive current collector 14 are sequentially fixedly connected by the positive riveting member 19. The negative post 13, the second upper insulating member 17, the cover plate 11, the lower insulating member 18, and the negative current collector 15 are sequentially fixedly connected by the negative riveting member 20. Through the mutual cooperation between the above-mentioned structures, the first upper insulating member 16 and the second upper insulating member 17 can be used to insulate the positive post 12 and the negative post 13 from the cover plate 11. The lower insulating member 18 can be used to insulate the positive current collector 14 and the negative current collector 15 from the cover plate 11, as well as to insulate the winding core 3 from the cover plate 11. In the present embodiment, the positive riveting member 19 and the negative riveting member 20 are both rivets or other structural members that can achieve riveting function.

[0055] In the present embodiment, sealing members S are provided between the positive riveting member 19, the negative riveting member 20, and the cover plate 11 to achieve insulation and sealing connection between the positive riveting member 19, the negative riveting member 20, and the cover plate, thereby preventing electrolyte leakage.

[0056] As some preferred embodiments, the lower insulating member 18 has an annular flange 180 on its bottom surface that contacts the end surface of the winding core 3. The annular flange 180 on the bottom surface of the lower insulating member 18 supports the winding core 3 by contacting its end surface, thereby fixing the winding core 3. The bent tabs and the current collectors are not subjected to extrusion force between the lower insulating member 18 and the winding core 3, and there is no risk of stress concentration leading to fracture of the current collectors, which improves the safety performance of the battery.

[0057] As some preferred embodiments, the positive current collector 14 and the positive pole 12 and the positive tab 31a on the winding core 3 are made of the same material, and the negative current collector 15 and the negative pole 13 and the negative tab 32a on the winding core 3 are made of the same material. In this way, after the same metal materials are welded with each other, on the one hand, the stability and reliability of the welding can be improved, and on the other hand, the contact resistance between the components can be reduced, and the overcurrent capacity can be improved. For example, the positive pole 12 is made of aluminum material, the negative pole 13 is made of copper material, and the positive current collector 14 and the positive tab 31a are made of aluminum foil material, and the negative current collector 15 and the negative tab 32a are made of copper foil material.

[0058] The application further discloses a cylindrical battery. Figures 5-7 , comprising a shell 2, a winding core 3 arranged in the shell 2 and the battery cover plate assembly 1 disclosed in the above embodiments.

[0059] In the embodiment, the winding core 3 is formed by winding a positive plate, a diaphragm and a negative plate, and the winding process belongs to the prior art. A plurality of positive tabs 31a of the positive plate and a plurality of negative tabs 32a of the negative plate are located on the same end surface of the winding core 3. In the embodiment, the positive and negative tabs with different intervals and sizes are cut out on the positive and negative plates by die cutting. Through winding calculation, after the winding of the winding core 3 is completed, the plurality of positive tabs 31a and the plurality of negative tabs 32a are symmetrically distributed relative to the center of the winding core 3. Specifically, the positive tabs 31a and the negative tabs 32a are arranged in the radial direction of the winding core 3. After the winding is completed, the positive and negative tabs extend out of the end of the winding core 3 and are flush with the axial direction of the winding core 3. The positive current collector 14 and the negative current collector 15 disclosed in the embodiment are an independent whole and cannot be directly welded with the plurality of positive tabs 31a and the plurality of negative tabs 32a.

[0060] In the prior art, the plurality of positive tabs 31a and the plurality of negative tabs 32a are flattened on the end surface of the winding core 3 by the flattening process. For the winding core 3 with the positive and negative tabs on both ends, it is relatively easy to flatten the tabs. However, for the winding core 3 with the positive and negative tabs on the same end, the flattening process is relatively troublesome.

[0061] In the embodiment, a plurality of positive tabs 31a are stacked along the radial direction of the winding core 3 to form a positive tab cluster 31, and a plurality of negative tabs 32a are stacked along the radial direction of the winding core 3 to form a negative tab cluster 32. Specifically, a plurality of positive tabs 31a are stacked together along the radial direction of the winding core 3, and then ultrasonic welding is performed to connect the plurality of positive tabs 31a together to form a positive tab cluster 31 with a certain thickness. At this time, the positive tab cluster 31 is still flush with the axial direction of the winding core 3. Similarly, a plurality of negative tabs 32a are stacked together along the radial direction of the winding core 3, and then ultrasonic welding is performed to connect the plurality of negative tabs 32a together to form a negative tab cluster 32 with a certain thickness. At this time, the negative tab cluster 32 is still flush with the axial direction of the winding core 3.

[0062] In this way, the positive tab cluster 31 and the negative tab cluster 32 are also composed of multiple layers of foil and also have a certain flexibility. The end of the positive current collector 14 away from the positive column 12 is welded to the positive tab cluster 31, and the end of the negative current collector 15 away from the negative column 13 is welded to the negative tab cluster 32. Since the positive current collector 14 and the negative current collector 15 have flexibility, and the matching positive tab cluster 31 and the negative tab cluster 32 on the winding core 3 also have flexibility, the current collector and the tab cluster can be flexibly bent after welding, the bending process is simple, and thus the winding core 3 and the cover plate 11 can be coaxial after bending, facilitating the battery into the shell.

[0063] In addition, a plurality of positive tabs 31a are stacked in the radial direction of the winding core 3 and form the positive tab cluster 31 by ultrasonic pre-welding, to be welded to the flexible positive current collector 14, and a plurality of negative tabs 32a are stacked in the radial direction of the winding core 3 and form the negative tab cluster 32 by ultrasonic pre-welding, to be welded to the negative current collector 15, eliminating the rubbing and flattening process step of the full-tab winding core 3, and simplifying the battery manufacturing process.

[0064] Since the current collector and the tab are both multi-layer foil structures, the size, thickness and number of layers of the foil can be determined according to design needs, fully meeting the overcurrent requirements of the large cylindrical battery winding core 3 and the cover plate 11, and being suitable for the design and use of large-capacity and large-rate cylindrical batteries. At the same time, the tabs of the winding core 3 are on the same side, and the single cover plate 11 structure improves the space utilization of the winding core 3 in the height direction, which is beneficial to improve the energy density of the battery.

[0065] At the same time, the tabs on the end surface of the winding core 3 are not subjected to rubbing and flattening and have a non-dense open structure, so that the electrolyte can more easily infiltrate the internal tabs of the battery during liquid injection, which can greatly reduce the liquid injection time of the battery and improve the production efficiency

[0066] In order to align the tabs in the positive tab cluster 31 and the negative tab cluster 32 formed on the winding core 3 in the height direction and facilitate welding with the positive and negative current collectors, the scheme adopted in this embodiment is that the heights of the plurality of positive tabs 31a gradually increase from the center of the positive tab cluster 31 to both sides, and the heights of the plurality of negative tabs 32a gradually increase from the center of the negative tab cluster 32 to both sides. In this way, the plurality of positive tabs 31a are drawn together in the radial direction, the outermost positive tab 31a has a relatively long length, and when drawn to the center of the positive tab cluster 31, it successively presses the inner positive tabs 31a, and the lengths of the positive tabs 31a from the outside to the inside decrease in turn, so that after the positive tabs 31a on both sides are drawn and stacked in the middle, the top ends of all the positive tabs 31a can be flush.

[0067] Similarly, the plurality of negative tabs 32a are moved towards the center in the radial direction, the outermost negative tab 32a is long, and when moving towards the center of the negative tab cluster 32, the inner negative tab 32a is sequentially pressed down, and the length of the negative tab 32a from the outside to the inside decreases sequentially, so that the negative tabs 32a on both sides can be stacked after moving towards the middle, and the top ends of all the negative tabs 32a can be flush.

[0068] In order to facilitate the connection of the positive and negative current collectors through the riveting process and the positive and negative poles 13, a first connecting hole 141 connected with the positive riveting part 19 is arranged on one end surface of the positive current collector 14, and the other end surface of the positive current collector 14 is welded with the side surface of the positive tab cluster 31; a second connecting hole 142 connected with the negative riveting part 20 is arranged on one end surface of the negative current collector 15, and the other end surface of the negative current collector 15 is welded with the side surface of the negative tab cluster 32.

[0069] Therefore, the positive riveting part 19 passes through the first connecting hole 141 to be connected with the one end surface of the positive current collector 14, and the other end surface of the positive current collector 14 is welded with the side surface of the positive tab cluster 31, so that the welding area can be increased and the welding yield can be ensured; the negative riveting part 20 passes through the second connecting hole 142 to be connected with the one end surface of the negative current collector 15, and the other end surface of the negative current collector 15 is welded with the side surface of the negative tab cluster 32, so that the welding area can be increased and the welding yield can be ensured.

[0070] The center of the cover plate 11 is provided with a liquid injection hole 110, and the positive pole 12 and the negative pole 13 are symmetrically arranged relative to the liquid injection hole 110, and the center of the lower insulating part 18 is provided with a through hole 181 coaxial with the liquid injection hole 110. By arranging the liquid injection hole 110 in the center of the cover plate 11, the electrolyte can quickly infiltrate the entire winding core 3 in the shell 2, and the winding core 3 is not subjected to the rubbing process, so that the electrolyte can more easily infiltrate the internal pole piece of the battery during liquid injection, thereby greatly reducing the liquid injection time of the battery and improving the production efficiency.

[0071] The present application also provides an assembling process of a cylindrical battery, comprising the following steps:

[0072] S1, cutting out positive and negative pole pieces with different intervals and sizes;

[0073] S2, winding the positive and negative pole pieces and the separator to form a winding core 3, and arranging the positive and negative tabs on the same end of the winding core 3, and keeping the positive and negative tabs symmetrically distributed relative to the center of the winding core 3;

[0074] S3, stacking a plurality of positive tabs 31a along the radial direction of the winding core 3 and pre-welding by ultrasonic wave to form a positive tab cluster 31, and stacking a plurality of negative tabs 32a along the radial direction of the winding core 3 and pre-welding by ultrasonic wave to form a negative tab cluster 32;

[0075] S4, one end surface of the positive current collector 14 is ultrasonically welded with the side surface of the positive tab cluster 31, and the other end is connected with the positive post 12 through the positive rivet 19, one end surface of the negative current collector 15 is ultrasonically welded with the side surface of the negative tab cluster 32, and the other end is connected with the negative post 13 through the negative rivet 20;

[0076] S5, the winding core 3 is put into the shell 2, and the shell 2 is closed and fixed through the cover plate 11 at the open end, and the assembly of the cylindrical battery is completed.

[0077] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cylindrical battery, comprising a casing (2), a core (3) and a battery cover assembly, wherein the battery cover assembly comprises a cover plate (11), a positive terminal post (12) and a negative terminal post (13), wherein the positive terminal post (12) and the negative terminal post (13) are fixedly disposed on the cover plate (11) at intervals and are electrically isolated from the cover plate (11); Its features are: It also includes a positive current collector (14) and a negative current collector (15) configured as flexible structures; the positive current collector (14) and the negative current collector (15) are both formed by welding together multiple layers of metal foil; One end of the positive current collector (14) is fixedly connected to the positive terminal post (12), and the other end is welded to the positive terminal lug (31a) on the core (3); One end of the negative electrode current collector (15) is fixedly connected to the negative electrode post (13), and the other end is welded to the negative electrode lug (32a) on the core (3); As the cover plate (11) approaches the end of the core (3), the positive current collector (14) and the negative current collector (15) are bent and compressed so that the cover plate (11) covers the end of the core (3) and remains coaxially aligned; The core (3) is formed by winding a positive electrode sheet, a separator and a negative electrode sheet. The core (3) is disposed inside the housing (2). Several positive electrode tabs (31a) of the positive electrode sheet and several negative electrode tabs (32a) of the negative electrode sheet are located on the same end face of the core (3). Several positive electrode tabs (31a) and several negative electrode tabs (32a) are symmetrically distributed with respect to the center of the core (3). Several positive electrode tabs (31a) are stacked along the radial direction of the core (3) to form a positive electrode tab cluster (31), and several negative electrode tabs (32a) are stacked along the radial direction of the core (3) to form a negative electrode tab cluster (32). The end of the positive electrode current collector (14) away from the positive electrode post (12) is welded to the positive electrode tab cluster (31), and the end of the negative electrode current collector (15) away from the negative electrode post (13) is welded to the negative electrode tab cluster (32). The cover plate (11) is fixedly connected to the opening end of the housing (2). The height of several positive electrode tabs (31a) gradually increases from the center of the positive electrode tab cluster (31) to both sides, and the height of several negative electrode tabs (32a) gradually increases from the center of the negative electrode tab cluster (32) to both sides.

2. The cylindrical battery as described in claim 1, characterized in that: The battery cover assembly also includes a first upper insulating component (16), a second upper insulating component (17), a lower insulating component (18), a positive electrode riveting component (19), and a negative electrode riveting component (20). The positive electrode post (12), the first upper insulating component (16), the cover plate (11), the lower insulating component (18), and the positive electrode current collector (14) are sequentially fixedly connected by the positive electrode riveting component (19). The negative electrode post (13), the second upper insulating component (17), the cover plate (11), the second lower insulating component (18), and the negative electrode current collector (15) are sequentially fixedly connected by the negative electrode riveting component (20).

3. The cylindrical battery as described in claim 2, characterized in that: The bottom surface of the lower insulating member (18) is provided with an annular flange (180) that contacts the end face of the core (3).

4. The cylindrical battery as described in claim 1, characterized in that: The positive electrode current collector (14), the positive electrode post (12), and the positive electrode tab (31a) on the core (3) are made of the same material, and the negative electrode current collector (15), the negative electrode post (13), and the negative electrode tab (32a) on the core (3) are made of the same material.

5. The cylindrical battery as described in claim 1, characterized in that: The positive current collector (14) has a first connecting hole (141) on one end surface that connects to the positive riveting member (19), and the other end surface of the positive current collector (14) is welded to the side of the positive ear cluster (31); the negative current collector (15) has a second connecting hole (142) on one end surface that connects to the negative riveting member (20), and the other end surface of the negative current collector (15) is welded to the side of the negative ear cluster (32).

6. The cylindrical battery as described in claim 2, characterized in that: The cover plate (11) has a liquid injection hole (110) at its center. The positive electrode post (12) and the negative electrode post (13) are symmetrically arranged with respect to the liquid injection hole (110). The lower insulating member (18) has a through hole (181) at its center that is coaxial with the liquid injection hole (110).

7. An assembly process for a cylindrical battery as described in any one of claims 2 to 6, characterized in that, Includes the following steps: S1. Cut out positive and negative electrode sheets with different spacing and sizes of multi-pole tabs; S2. The positive and negative electrode sheets and the separator are wound to form a core (3), and the positive and negative electrode tabs (32a) are on the same end of the core (3), and the positive and negative electrode tabs (32a) are symmetrically distributed with respect to the center of the core (3). S3. Several positive electrode tabs (31a) are stacked along the radial direction of the core (3) and pre-welded by ultrasonic waves to form a positive electrode tab cluster (31). Several negative electrode tabs (32a) are stacked along the radial direction of the core (3) and pre-welded by ultrasonic waves to form a negative electrode tab cluster (32). S4. One end surface of the positive current collector (14) is ultrasonically welded to the side of the positive ear cluster (31), and the other end is connected to the positive post (12) through the positive riveting piece (19). One end surface of the negative current collector (15) is ultrasonically welded to the side of the negative ear cluster (32), and the other end is connected to the negative post (13) through the negative riveting piece (20). S5. Place the core (3) into the housing (2) and seal it by passing the cover plate (11) through the opening of the housing (2) to complete the assembly of the cylindrical battery.

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