A full-tab large cylindrical lithium ion battery and an assembling method thereof

Abstract

The application discloses a full-tab large cylindrical lithium ion battery and an assembling method thereof. The battery comprises a shell, a winding core, a positive electrode current collector plate assembly and a negative electrode current collector plate assembly. The positive electrode current collector plate and the negative electrode current collector plate are in an integrated structure with corresponding pole columns. The current collector plate is provided with a plurality of convex structures which can be pressed into the corresponding full-tab to increase the contact area. The positive electrode current collector plate is doubly insulated from the shell through an insulating spacer with an extended side wall. The shell is provided with a welding avoidance area and a positioning step part at both ends. The current collector plate is provided with a radial liquid injection channel. During the assembling, the current collector plate is pre-connected with the winding core and then is loaded into the shell. The sealing is welded in the order of inside first and outside later. The application can effectively reduce the battery internal resistance, improve the connection reliability and insulation safety, and balance the high energy density and the mass production assembly efficiency.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a large cylindrical lithium-ion battery with multiple tabs and its assembly method. Background Technology

[0002] As the requirements for energy density and high-rate charge / discharge performance of new energy power batteries continue to increase, large cylindrical all-tab batteries have become the mainstream development direction in the industry due to their advantages of high space utilization and low internal resistance. However, existing large cylindrical all-tab batteries still have significant technical defects: First, the current collector and the terminal post are mostly made of separate welding structure, which not only increases the assembly process, but also introduces additional contact internal resistance, making them prone to welding failure during long-term use; Second, the current collector and the all-tab are welded in planar contact, with limited contact area, which makes them prone to problems such as poor welding, excessive contact resistance, and overheating due to concentrated current; Third, the assembly process is cumbersome, the welding yield is low, and the mass production consistency is poor, which restricts its large-scale promotion and application. Summary of the Invention

[0003] To overcome the shortcomings of existing technical solutions, this invention provides a large cylindrical lithium-ion battery with all tabs and its assembly method, which can effectively solve the problems raised in the background art.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A cylindrical lithium-ion battery with multiple tabs includes a cylindrical casing and a core housed within the casing. The casing has a first end and a second end. The core has positive and negative tabs formed from foil ends, respectively, at its two ends. The battery also includes:

[0006] A positive current collector assembly is disposed at the first end of the housing and is insulated from the housing. The positive current collector assembly includes a positive current collector body, a positive electrode post, and a positive insulating isolation component. The positive current collector body and the positive electrode post are integrally formed. The positive current collector body is welded to the positive electrode tab. The positive insulating isolation component is sleeved on the outer periphery of the positive electrode post and sandwiched between the positive current collector body and the first end wall of the housing.

[0007] A negative current collector assembly is disposed at the second end of the housing. The negative current collector assembly includes a negative current collector body and a negative current post. The negative current collector body and the negative current post are integrally formed. The negative current collector body is welded to the negative current lug. The negative current collector body is electrically connected to the housing.

[0008] The positive current collector and the negative current collector each have multiple protruding structures facing the core. The protruding structures are pressed into the corresponding positive or negative full electrode tab to increase the contact area between the current collector and the tab.

[0009] As a further description of the above technical solution, the positive electrode insulating separator includes an annular bottom wall and a side wall extending from the outer periphery of the annular bottom wall toward the core direction. The side wall extends axially along the inner circumferential surface of the housing for a predetermined length, so as to provide insulation between the outer edge of the positive electrode current collector body and the inner wall of the housing.

[0010] As a further description of the above technical solution, a through hole is provided on the first end wall of the housing for the positive electrode post to pass through, and a welding avoidance area is formed on the outer side of the first end wall of the housing corresponding to the periphery of the through hole, and the positive electrode post is fixed to the first end wall of the housing by external welding at the through hole.

[0011] As a further description of the above technical solution, the second end of the housing is an integral closed structure, and an annular step portion is provided on the inner side of the second end of the housing. The outer edge of the negative electrode current collector body overlaps on the annular step portion and is laser welded to the housing.

[0012] As a further description of the above technical solution, the protruding structure is a hemispherical protrusion formed by stamping, and multiple protruding structures are arranged in a circular array with the center of the positive current collector body as the center.

[0013] As a further description of the above technical solution, the positive electrode current collector body and the negative electrode current collector body are respectively provided with a plurality of radially extending strip-shaped through holes, which are distributed circumferentially to form a liquid injection channel for the flow of electrolyte.

[0014] A method for assembling a large cylindrical lithium-ion battery with all tabs includes the following steps:

[0015] Step S1, providing a winding core with a full-tab structure, wherein the two ends of the winding core have a positive full-tab and a negative full-tab formed by foil ends, respectively;

[0016] Step S2: Provide an integrally formed positive current collector and positive terminal, and an integrally formed negative current collector and negative terminal, wherein multiple protrusion structures are pre-formed on the inner surfaces of the positive current collector and the negative current collector.

[0017] Step S3: Provide a positive electrode insulating isolation component, sleeve the positive electrode insulating isolation component on the outer periphery of the positive electrode post, and then press the positive electrode current collector onto the positive electrode tab end face of the winding core, so that the protruding structure is pressed into the inside of the positive electrode tab, and apply welding energy to fuse the protruding structure and the positive electrode tab together to form a pre-connected body of the positive electrode current collector assembly and the winding core;

[0018] Step S4: Press the negative current collector onto the negative electrode tab end face of the core, so that the protruding structure is pressed into the inside of the negative electrode tab, and weld it so that the protruding structure and the negative electrode tab are fused together.

[0019] Step S5: The assembly formed in steps S3 and S4 is installed into the housing, so that the positive electrode insulating isolation component is sandwiched between the positive electrode current collector and the first end wall of the housing, and the positive electrode post passes through the through hole on the first end wall of the housing.

[0020] Step S6: Weld the negative current collector to the second end of the housing, and externally weld the positive terminal to the housing on the outer side of the first end wall of the housing.

[0021] As a further description of the above technical solution, in step S3, the positive electrode insulating separator includes an annular bottom wall and a side wall extending from the outer periphery of the annular bottom wall toward the core direction;

[0022] During assembly, the sidewall extends axially along the inner circumferential surface of the housing, so that the outer edge of the positive current collector is insulated from the inner wall of the housing through the sidewall.

[0023] As a further description of the above technical solution, the welding of the negative electrode current collector to the second end of the housing is carried out before the welding of the positive electrode post to the outer end wall of the first end of the housing.

[0024] As a further description of the above technical solution, in step S5, the maximum outer diameter of the assembly is smaller than the inner diameter of the shell, so that the assembly is installed into the shell in a clearance fit manner, and the outer diameter of the positive electrode insulating isolator and the inner diameter of the shell are interference fit.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The present invention provides a large cylindrical lithium-ion battery with multiple tabs and its assembly method, which has at least one of the following beneficial effects during use:

[0027] The integrated design of the current collector and terminal post eliminates the contact resistance and welding failure risks associated with separate welding, effectively reducing the overall internal resistance of the battery, significantly improving high-current charge and discharge performance, and reducing heat generation during battery operation. The raised structure of the current collector is pressed into the terminal tab to form a three-dimensional contact weld, significantly improving the connection strength between the current collector and the terminal tab, effectively avoiding problems such as incomplete welding and desoldering, achieving uniform current conduction, eliminating local overheating, and improving the connection stability of the battery during cycle use. The positive electrode insulating separator provides axial and radial double insulation protection, completely eliminating the risk of short circuits between the positive and negative electrodes, and significantly improving battery safety performance. Combined with the optimized shell positioning structure and assembly process, assembly efficiency and accuracy are significantly improved, and the electrolyte injection channel optimizes the electrolyte wetting effect, taking into account the battery's high energy density, high reliability, and mass production compatibility. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a partial cross-sectional structure of a large cylindrical lithium-ion battery with multiple tabs according to the present invention.

[0029] Figure 2 This is a schematic diagram of the axial cross-sectional structure of a large cylindrical lithium-ion battery with multiple tabs according to the present invention.

[0030] Figure 3 This is a first perspective structural schematic diagram of a large cylindrical lithium-ion battery with multiple tabs according to the present invention.

[0031] Figure 4 This is a second perspective structural diagram of a large cylindrical lithium-ion battery with multiple tabs according to the present invention;

[0032] Figure 5 This is a flowchart illustrating the steps of assembling a large cylindrical lithium-ion battery with all tabs according to the present invention.

[0033] Numbering on the map:

[0034] 1. Shell; 2. Core; 3. First end; 4. Second end; 5. Positive current collector assembly; 6. Negative current collector assembly; 7. Positive insulating separator; 8. Positive full-pole tab; 9. Negative full-pole tab; 10. Negative pole post; 11. Annular bottom wall; 12. Positive current collector body; 13. Positive pole post; 14. Negative current collector body; 15. Protruding structure; 16. Strip-shaped through hole; 17. Annular stepped section. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figure 1-5 As shown, the present invention provides a large cylindrical lithium-ion battery with multiple tabs, including a cylindrical housing 1 and a core 2 housed within the housing 1. The housing 1 has a first end 3 and a second end 4. The two ends of the core 2 are respectively formed with positive electrode tabs 8 and negative electrode tabs 9, which are composed of foil ends. The battery also includes:

[0037] A positive current collector assembly 5 is disposed at the first end 3 of the housing 1 and is insulated from the housing 1. The positive current collector assembly 5 includes a positive current collector body 12, a positive electrode post 13 and a positive insulating isolation component 7. The positive current collector body 12 and the positive electrode post 13 are integrally formed. The positive current collector body 12 is welded to the positive electrode lug 8. The positive insulating isolation component 7 is sleeved on the outer periphery of the positive electrode post 13 and sandwiched between the positive current collector body 12 and the end wall of the first end 3 of the housing 1.

[0038] The positive electrode insulating isolator 7 achieves axial insulation between the positive electrode current collector and the end wall of the housing 1 through the annular bottom wall 11, and achieves radial insulation between the outer edge of the positive electrode current collector and the inner wall of the housing 1 through the extended side wall, thus completely blocking the conductive path between the positive electrode and the housing 1 (negative electrode potential) and eliminating the risk of radial and axial short circuits.

[0039] The negative electrode current collector assembly 6 is disposed at the second end 4 of the housing 1. The negative electrode current collector assembly 6 includes a negative electrode current collector body 14 and a negative electrode post 10. The negative electrode current collector body 14 and the negative electrode post 10 are integrally formed. The negative electrode current collector body 14 is welded to the negative electrode lug 9. The negative electrode current collector body 14 is electrically connected to the housing 1.

[0040] The positive current collector body 12 and the positive electrode post 13, and the negative current collector body 14 and the negative electrode post 10 are all integrally formed, eliminating the welding connection interface between the current collector and the post in the traditional split structure. The current is directly conducted from the tab to the post through the current collector, without additional welding contact resistance, and at the same time avoiding the risk of failure of the split welding.

[0041] The annular stepped portion of the negative end provides radial and axial positioning for the negative current collector. The outer edge of the current collector is overlapped and welded to achieve a reliable electrical connection over a large area. The welding avoidance area of ​​the positive end provides process space for external welding, avoiding solder overflow and heat damage, while also achieving a fixed seal between the pole and the housing 1.

[0042] The positive current collector plate body 12 and the negative current collector plate body 14 each have a plurality of protruding structures 15 facing the core 2. The protruding structures 15 are pressed into the corresponding positive full electrode tab 8 or negative full electrode tab 9 to increase the contact area between the current collector plate and the tab.

[0043] The raised structure 15 on the current collector is pressed into the gap between the foil layers of the full tab, transforming the traditional planar end face contact between the current collector and the tab into a three-dimensional embedded contact, which greatly increases the actual contact area between the two. During welding, the raised structure and the tab foil fully melt to form a multi-point three-dimensional welding node, which not only improves the connection strength but also realizes the uniform conduction of current through multiple paths, avoiding local current concentration and overheating.

[0044] In this embodiment, the current collector and terminal post are integrally formed, eliminating the internal resistance of separate welding. The raised three-dimensional contact reduces the contact resistance between the current collector and the terminal tab, resulting in an overall internal resistance reduction of more than 30% compared to traditional structures. This supports higher charge and discharge rates and reduces heat generation during high-current operation. The connection strength of the raised embedded welding is more than twice that of planar welding, avoiding desoldering and cold solder joint problems under vibration and impact conditions, and significantly improving connection stability during battery cycling. The axial and radial double insulation structure solves the short-circuit risk between the positive electrode and the casing 1 caused by the misalignment of the core 2, greatly improving battery safety performance. The integrated design of the current collector and terminal post reduces the number of parts, with the casing 1 directly serving as the negative electrode output terminal, simplifying the end structure, improving the internal space utilization of the battery, and contributing to increased energy density.

[0045] Furthermore, the positive electrode insulating separator 7 includes an annular bottom wall 11 and a side wall extending from the outer periphery of the annular bottom wall 11 toward the core 2. The side wall extends axially along the inner circumferential surface of the housing 1 for a predetermined length, so as to provide insulation between the outer edge of the positive electrode current collector body 12 and the inner wall of the housing 1.

[0046] The extended sidewall of the positive electrode insulating isolator 7 achieves radial insulation protection, which solves the problem of short circuit between the outer edge of the current collector and the inner wall of the housing 1 caused by the offset of the core 2 when it is installed into the housing 1. The insulation protection has no dead angle. At the same time, the sidewall can radially limit the current collector to avoid the current collector from swaying.

[0047] Furthermore, a through hole is provided on the first end 3 end wall of the housing 1 for the positive electrode post 13 to pass through. A welding avoidance area is formed on the outer side of the first end 3 end wall of the housing 1 corresponding to the periphery of the through hole. The positive electrode post 13 is fixed to the first end 3 end wall of the housing 1 by external welding at the through hole.

[0048] The welding avoidance area at the end of the casing 1 provides process space for external welding, avoiding solder overflow and contamination of the battery interior during welding, while reducing the conduction of welding heat to the insulating separator and preventing the insulating separator from failing due to heat; the external welding process does not require operation inside the casing 1, the process is simple, and the welding consistency is good.

[0049] Furthermore, the second end 4 of the housing 1 is an integral closed structure, and the inner side of the second end 4 of the housing 1 is provided with an annular step portion 17. The outer edge of the negative electrode current collector body 14 overlaps on the annular step portion 17 and is laser welded to the housing 1.

[0050] The annular step 17 at the negative end enables precise positioning of the negative current collector, eliminating the need for additional tooling alignment during assembly and improving assembly efficiency; the lap welding has a large contact area, resulting in higher electrical connection reliability and lower internal resistance in the negative circuit, while the step can prevent welding slag from entering the core 2.

[0051] Furthermore, the protruding structure 15 is a hemispherical protrusion formed by stamping, and multiple protruding structures 15 are arranged in a circular array with the center of the positive current collector body 12 as the center.

[0052] The hemispherical protrusion stamping process is simple and has high production efficiency. When the spherical structure is pressed into the electrode tab, it can evenly compress the foil without puncturing the electrode tab foil. The circumferential array arrangement makes the contact points evenly distributed, the current conduction is more uniform, avoids local overheating, the welding point is evenly stressed, and the vibration and impact resistance is better.

[0053] Furthermore, the positive electrode current collector body 12 and the negative electrode current collector body 14 are respectively provided with a plurality of radially extending strip-shaped through holes 16, which are distributed circumferentially to form a liquid injection channel for the flow of electrolyte.

[0054] The electrolyte injection channel formed by the radial strip-shaped through holes 16 allows the electrolyte to quickly penetrate from the center of the collector plate to the outer edge into the core 2, reducing the injection time by more than 40% and significantly improving the injection efficiency; at the same time, the electrolyte is more evenly wetted, avoiding local dry areas in the core 2 and improving the cycle life and capacity of the battery.

[0055] A method for assembling a large cylindrical lithium-ion battery with all tabs includes the following steps:

[0056] Step S1, a core 2 with a full-tab structure is provided, wherein the two ends of the core 2 have a positive full-tab 8 and a negative full-tab 9 formed by foil ends, respectively;

[0057] Step S2, providing an integrally formed positive current collector and positive terminal 13, and an integrally formed negative current collector and negative terminal 10, wherein multiple protrusion structures 15 are pre-formed on the inner surface of the positive current collector and the negative current collector.

[0058] Step S3: Provide a positive electrode insulating separator 7, sleeve the positive electrode insulating separator 7 on the outer periphery of the positive electrode post 13, and then press the positive electrode current collector onto the end face of the positive electrode tab 8 of the core 2, so that the protruding structure 15 is pressed into the inside of the positive electrode tab 8, and apply welding energy to fuse the protruding structure 15 and the positive electrode tab 8 into one piece, forming a pre-connected body between the positive electrode current collector assembly 5 and the core 2;

[0059] Step S4: Press the negative electrode current collector onto the end face of the negative electrode tab 9 of the core 2, so that the protruding structure 15 is pressed into the inside of the negative electrode tab 9, and weld it so that the protruding structure 15 and the negative electrode tab 9 are fused together.

[0060] Step S5: The assembly formed in steps S3 and S4 is installed into the housing 1, so that the positive electrode insulating isolation component 7 is sandwiched between the positive electrode current collector and the first end 3 end wall of the housing 1, and the positive electrode post 13 passes through the through hole on the first end 3 end wall of the housing 1.

[0061] Step S6: Weld the negative current collector to the second end 4 of the housing 1, and externally weld the positive electrode post 13 to the housing 1 on the outer side of the end wall of the first end 3 of the housing 1.

[0062] The integrated molding of the current collector and terminal post reduces the need for separate welding processes, and the pre-connector design simplifies the housing 1 installation process. Overall assembly processes are reduced by 30% compared to traditional methods, significantly improving production efficiency. The press-in pre-tightening followed by welding process fundamentally avoids the problem of incomplete welding caused by loose fit between the current collector and terminal tab, greatly improving welding yield. The pre-connector is integrally installed into housing 1, avoiding collisions and misalignments during the assembly of scattered parts, significantly reducing the damage rate of the core 2, and significantly improving battery assembly consistency.

[0063] Furthermore, in step S3, the positive electrode insulating separator 7 includes an annular bottom wall 11 and a side wall extending from the outer periphery of the annular bottom wall 11 toward the core 2;

[0064] During assembly, the sidewall extends axially along the inner circumferential surface of the housing 1, so that the outer edge of the positive current collector is insulated from the inner wall of the housing 1 by the sidewall.

[0065] During assembly, the sidewall of the insulating isolator extends along the inner circumferential surface of the housing 1, automatically achieving radial insulation between the positive current collector and the inner wall of the housing 1. No additional insulating parts are required, the assembly process is simple, and the insulation reliability is high.

[0066] Furthermore, in steps S5 and S6, the welding of the negative current collector to the second end 4 of the housing 1 is performed before the welding of the positive electrode post 13 to the outer wall of the first end 3 of the housing 1.

[0067] Welding the internal connection of the negative electrode first, and then welding the external seal of the positive electrode, can fix the position of the assembly by welding the negative electrode, avoiding the displacement of the pole and the misalignment of the insulation components caused by the movement of the assembly during the welding of the positive electrode. At the same time, the internal welding will not damage the sealing structure of the positive electrode. The process sequence is reasonable and the assembly accuracy is high.

[0068] Furthermore, in step S5, the maximum outer diameter of the assembly is smaller than the inner diameter of the housing 1, so that the assembly is installed into the housing 1 with a clearance fit, and the outer diameter of the positive electrode insulating separator 7 and the inner diameter of the housing 1 are interference fit.

[0069] The clearance fit between the assembly and the housing 1 ensures a smooth installation process and avoids scratching the tabs of the core 2; the interference fit between the insulating separator and the housing 1 not only achieves axial positioning of the assembly to prevent the core 2 from shifting during battery use, but also improves the sealing performance at the ends, reduces the risk of electrolyte leakage, and balances assembly convenience and structural stability.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A cylindrical lithium-ion battery with multiple tabs, comprising a cylindrical casing and a core housed within the casing, the casing having a first end and a second end, and the core having a positive electrode tab and a negative electrode tab formed by foil ends, respectively, characterized in that... Also includes: A positive current collector assembly is disposed at the first end of the housing and is insulated from the housing. The positive current collector assembly includes a positive current collector body, a positive electrode post, and a positive insulating isolation component. The positive current collector body and the positive electrode post are integrally formed. The positive current collector body is welded to the positive electrode tab. The positive insulating isolation component is sleeved on the outer periphery of the positive electrode post and sandwiched between the positive current collector body and the first end wall of the housing. A negative current collector assembly is disposed at the second end of the housing. The negative current collector assembly includes a negative current collector body and a negative current post. The negative current collector body and the negative current post are integrally formed. The negative current collector body is welded to the negative current lug. The negative current collector body is electrically connected to the housing. The positive current collector and the negative current collector each have multiple protruding structures facing the core. The protruding structures are pressed into the corresponding positive or negative full electrode tab to increase the contact area between the current collector and the tab.

2. The large cylindrical lithium-ion battery with multiple tabs according to claim 1, characterized in that, The positive electrode insulating separator includes an annular bottom wall and a side wall extending from the outer periphery of the annular bottom wall toward the core. The side wall extends axially along the inner circumferential surface of the housing for a predetermined length, so as to provide insulation between the outer edge of the positive electrode current collector body and the inner wall of the housing.

3. The large cylindrical lithium-ion battery with multiple tabs according to claim 1, characterized in that, The first end wall of the housing has a through hole for the positive electrode post to pass through. A welding avoidance area is formed on the outer side of the first end wall of the housing corresponding to the periphery of the through hole. The positive electrode post is fixed to the first end wall of the housing by external welding at the through hole.

4. The all-tab large cylindrical lithium-ion battery according to claim 1, characterized in that, The second end of the housing is an integral closed structure. The inner side of the second end of the housing is provided with an annular step portion. The outer edge of the negative electrode current collector body overlaps on the annular step portion and is laser welded to the housing.

5. The large cylindrical lithium-ion battery with multiple tabs according to claim 1, characterized in that, The protruding structure is a hemispherical protrusion formed by stamping, and multiple protruding structures are arranged in a circular array with the center of the positive current collector body as the center.

6. The large cylindrical lithium-ion battery with multiple tabs according to claim 1, characterized in that, The positive electrode current collector and the negative electrode current collector are respectively provided with multiple radially extending strip-shaped through holes, which are distributed circumferentially to form a liquid injection channel for the flow of electrolyte.

7. A method for assembling a large cylindrical lithium-ion battery with multiple tabs, characterized in that, Includes the following steps: Step S1, providing a winding core with a full-tab structure, wherein the two ends of the winding core have a positive full-tab and a negative full-tab formed by foil ends, respectively; Step S2: Provide an integrally formed positive current collector and positive terminal, and an integrally formed negative current collector and negative terminal, wherein multiple protrusion structures are pre-formed on the inner surfaces of the positive current collector and the negative current collector. Step S3: Provide a positive electrode insulating isolation component, sleeve the positive electrode insulating isolation component on the outer periphery of the positive electrode post, and then press the positive electrode current collector onto the positive electrode tab end face of the winding core, so that the protruding structure is pressed into the inside of the positive electrode tab, and apply welding energy to fuse the protruding structure and the positive electrode tab together to form a pre-connected body of the positive electrode current collector assembly and the winding core; Step S4: Press the negative current collector onto the negative electrode tab end face of the core, so that the protruding structure is pressed into the inside of the negative electrode tab, and weld it so that the protruding structure and the negative electrode tab are fused together. Step S5: The assembly formed in steps S3 and S4 is installed into the housing, so that the positive electrode insulating isolation component is sandwiched between the positive electrode current collector and the first end wall of the housing, and the positive electrode post passes through the through hole on the first end wall of the housing. Step S6: Weld the negative current collector to the second end of the housing, and externally weld the positive terminal to the housing on the outer side of the first end wall of the housing.

8. The assembly method according to claim 7, characterized in that, In step S3, the positive electrode insulating separator includes an annular bottom wall and a side wall extending from the outer periphery of the annular bottom wall toward the core direction; During assembly, the sidewall extends axially along the inner circumferential surface of the housing, so that the outer edge of the positive current collector is insulated from the inner wall of the housing through the sidewall.

9. The assembly method according to claim 7, characterized in that, In steps S5 and S6, the welding of the negative current collector to the second end of the housing is performed before the welding of the positive terminal post to the outer wall of the first end of the housing.

10. The assembly method according to claim 7, characterized in that, In step S5, the maximum outer diameter of the assembly is smaller than the inner diameter of the housing, so that the assembly is installed into the housing with a clearance fit, and the outer diameter of the positive electrode insulating isolator is interference-fitted with the inner diameter of the housing.

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