A rivetless riveting device and method for a cylindrical battery case

Abstract

The present application relates to a kind of rivetless riveting device of cylindrical battery shell, comprising: lower die;Upper die, including punch, for extending into the inside of the battery shell and the inner end of battery pole is extruded to rivet the battery pole on the battery shell, punch includes multiple, the working end of each punch is provided with chamfer at circumference, for the inner end of battery pole is extruded to make the inner end of battery pole outwardly spread an angle, the angle indicates the position of the inner end of battery pole after spreading deviates from its original position angle;Multiple punch makes the inner end of battery pole outwardly spread angle successively increases, and at least one punch makes the inner end of battery pole outwardly spread angle greater than 90 degrees.The rivetless riveting device of cylindrical battery shell described in the present application, concave die combination is positioned to cylindrical battery shell and pole, and the battery shell is supported by floating to the battery shell by the angle of multiple punch continuous change riveting.

Description

Technical Field

[0001] This invention relates to the field of battery processing technology, and in particular to a rivetless riveting device and method for cylindrical battery casings. Background Technology

[0002] Lithium-ion batteries are classified into three types based on their form: hard-case batteries, pouch batteries, and cylindrical batteries. Among them, cylindrical batteries have advantages such as high volumetric energy density, simple structure, ease of assembly, and standardization. The structure of a cylindrical battery includes a casing and cylindrical cells. The casing includes a top cover, a bottom cover, and cylindrical sidewalls. The cylindrical cells are installed inside the casing, with the positive electrode near the bottom cover and the negative electrode near the top cover.

[0003] In the production process of cylindrical batteries, a short pre-pressing process is often performed to initially form the battery terminals. For example, Chinese patent document CN115172999A discloses a cylindrical battery positive terminal crimping carrier, including a carrier, a first magnet, a second magnet, and a third magnet. The second magnet is semi-enclosed in shape and has a groove. The third magnet is fixedly set at the bottom of the groove. One end of the carrier is an insertion end, and the first magnet is fixedly set at the insertion end. The first and second magnets are correspondingly set, and the shape and size of the insertion end match the shape and size of the groove. The carrier is inserted into the groove through the insertion end and connected to the second magnet by magnetic attraction. External rivets and sealing rings are set in the groove and crimp the positive terminal of the cylindrical battery under the crimping of the carrier. However, this design has the following defects: the battery terminals are prone to inaccurate alignment with the casing, which can cause deformation and warping during the pre-pressing process. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem of severe deformation and warping of the lower plastic during the riveting process of cylindrical batteries in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides a rivetless riveting device for a cylindrical battery casing, comprising: a lower mold having a cavity for accommodating the battery casing and for fixing the battery casing from the bottom and the outside; and an upper mold including punches for extending into the battery casing to press the inner end of the battery terminal to rivet the battery terminal to the battery casing. The punches include multiple punches, each punch having a chamfer at its working end periphery for pressing the inner end of the battery terminal to unfold it outward by an angle, where the angle refers to the angle by which the unfolded position of the inner end of the battery terminal deviates from its original position. The multiple punches cause the angle of the inner end of the battery terminal to unfold outward to increase sequentially, and at least one punch causes the angle of the inner end of the battery terminal to unfold outward to be greater than 90 degrees.

[0006] In one embodiment of the present invention, the punch includes: a first punch with a first chamfer at the periphery of its working end, used to press the inner end of the battery terminal to unfold the inner end of the battery terminal outward by a first angle; a second punch with a second chamfer at the periphery of its working end, used to press the inner end of the battery terminal to unfold the inner end of the battery terminal outward by a second angle; and a third punch with a third chamfer at the periphery of its working end, used to press the inner end of the battery terminal to unfold the inner end of the battery terminal outward by a third angle; wherein the first angle, the second angle, and the third angle all refer to the angle by which the unfolded position of the inner end of the battery terminal deviates from its original position, the first angle, the second angle, and the third angle increase sequentially, and the third angle is greater than 90 degrees.

[0007] In one embodiment of the present invention, the lower mold includes: a lower mold base; a housing positioning fixture disposed on the lower mold base, wherein the housing positioning fixture has a cavity formed in the middle for accommodating the battery housing; a cavity mold disposed on the lower mold base and coaxially disposed with the housing positioning fixture, for supporting the outer end of the battery terminal post; and a support member disposed on the lower mold base and located outside the cavity mold, for supporting the outer end face of the battery housing.

[0008] In one embodiment of the present invention, an elastic element is provided between the support member and the lower mold base.

[0009] In one embodiment of the present invention, the upper mold further includes: a mold mounting base for mounting the punch; a pre-pressing block sleeved on the outside of the punch; and a telescopic connecting mechanism for mounting the pre-pressing block onto the mold mounting base, so that the pre-pressing block can slide along the axial direction of the punch.

[0010] In one embodiment of the present invention, there are multiple mold mounting bases, each used to mount a plurality of the punches.

[0011] In one embodiment of the present invention, the mold mounting base is connected to an adapter.

[0012] In one embodiment of the present invention, the outer diameter of the first portion of the mold mounting base near the working end of the punch is smaller than that of the second portion away from the working end of the punch. The telescopic connection mechanism includes: a sleeve sleeved on the outside of the first portion of the mold mounting base; a sliding sleeve sleeved on the outside of the punch and connected to the pre-pressing block, at least a portion of the sliding sleeve being located inside the sleeve; and a spring located between the first portion of the mold mounting base and the sleeve, with both ends abutting against the sliding sleeve and the mold mounting base respectively.

[0013] The present invention also provides a rivetless riveting method for a cylindrical battery casing, comprising:

[0014] Insert the battery terminals into the predetermined positions on the battery casing end caps from the outside;

[0015] The battery terminal is repeatedly pressed by a punch with different bevel angles at its working end to expand outwards until the expansion angle is greater than 90 degrees, so that the battery terminal is riveted to the battery housing.

[0016] In one embodiment of the present invention, the punch includes a first punch, a second punch, and a third punch. The step of repeatedly pressing the end of the battery terminal located inside the battery casing to sequentially expand the inner end of the battery terminal outward specifically includes:

[0017] The inner end of the battery terminal is pressed by the first punch to make the inner end of the battery terminal unfold outward at a first angle.

[0018] The inner end of the battery terminal is pressed by the second punch to make the inner end of the battery terminal unfold outward at a second angle.

[0019] The inner end of the battery terminal is squeezed by the third punch, causing the inner end of the battery terminal to unfold outward at a third angle.

[0020] Wherein, the first angle, the second angle, and the third angle all refer to the angles at which the inner end of the battery terminal deviates from its original position after being unfolded. The first angle, the second angle, and the third angle increase sequentially, and the third angle is greater than 90 degrees.

[0021] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0022] The rivetless riveting device for cylindrical battery casings of the present invention comprises a concave mold assembly and a convex mold assembly. The concave mold assembly positions the cylindrical battery casing and the terminal post, and provides floating support for the cylindrical battery casing. The convex mold assembly is equipped with a fixed forming mold, which includes three types of molds: a pre-riveting mold, a riveting mold, and a shaping mold. During the riveting process of the cylindrical battery casing, a three-stage riveting process is adopted: pre-riveting—riveting—shaping. The convex mold assembly includes a floating pre-pressing mechanism to flatten the lower plastic and prevent excessive warping during the riveting process. Attached Figure Description

[0023] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0024] Figure 1 This is a schematic diagram of the rivetless riveting device for the cylindrical battery casing in a preferred embodiment of the present invention;

[0025] Figure 2 This is a cross-sectional view of the die assembly in a preferred embodiment of the present invention;

[0026] Figure 3 This is a cross-sectional view of the cylindrical battery casing in a preferred embodiment of the present invention;

[0027] Figure 4 This is a partial enlarged view of the cylindrical battery casing in a preferred embodiment of the present invention;

[0028] Figure 5 This is a cross-sectional view of the punch assembly in a preferred embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure before the pole post is riveted in a preferred embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the pre-riveting mold in a preferred embodiment of the present invention;

[0031] Figure 8 This is a schematic diagram of the structure after the pole post is pre-riveted in a preferred embodiment of the present invention;

[0032] Figure 9 This is a schematic diagram of the riveting mold in a preferred embodiment of the present invention;

[0033] Figure 10 This is a schematic diagram of the structure after the pole post is riveted in a preferred embodiment of the present invention;

[0034] Figure 11 This is a schematic diagram of the shaping mold in a preferred embodiment of the present invention;

[0035] Figure 12 This is a schematic diagram of the structure after pole post shaping in a preferred embodiment of the present invention;

[0036] Figure 13 The image shows the actual product after pre-riveting, riveting, and shaping of the cylindrical battery casing in a preferred embodiment of the present invention.

[0037] Explanation of reference numerals in the accompanying drawings: Lower mold base 1, Positioning hole 11, Die assembly 2, Housing positioning sleeve 21, First step 211, Second step 212, Die 22, Floating support block 23, Positioning post 231, First boss 232, Floating spring 24, Cylindrical battery housing 3, Battery outer shell 31, First lower plastic part 32, Second lower plastic part 33, Sealing ring 34, Terminal post 35, Upper plastic part 36, Punch assembly 4, Adapter assembly 41, First adapter 411, Second adapter 412, Mold mounting base 42, Third step 421, First through hole 422, Fourth step 423, Preload spring 43, Punch sleeve 44, Fifth step 441, Punch sliding sleeve 45, Second through hole 451, Sixth step 452, Limiting end 461, Preload block 49, Third through hole 491. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. Example

[0039] The rivetless riveting device for a cylindrical battery casing of the present invention includes: a lower die having a cavity for accommodating the battery casing and for fixing the battery casing from the bottom and the outside; and an upper die including a punch for extending into the battery casing to press the inner end of a battery terminal to rivet the battery terminal to the battery casing. The punch includes multiple punches, each with a chamfered edge at its working end, for pressing the inner end of the battery terminal to unfold it outwards by an angle, where the angle refers to the angle by which the unfolded position of the inner end of the battery terminal deviates from its original position. The multiple punches cause the angle of the inner end of the battery terminal to unfold outwards to increase sequentially, and at least one punch causes the angle of the inner end of the battery terminal to unfold outwards to be greater than 90 degrees.

[0040] Specifically, there are three punches: a first punch with a first chamfer at the periphery of its working end, used to press the inner end of the battery terminal to unfold it outward at a first angle; a second punch with a second chamfer at the periphery of its working end, used to press the inner end of the battery terminal to unfold it outward at a second angle; and a third punch with a third chamfer at the periphery of its working end, used to press the inner end of the battery terminal to unfold it outward at a third angle. The first angle, second angle, and third angle all refer to the angle by which the unfolded position of the inner end of the battery terminal deviates from its original position. The first angle, second angle, and third angle increase sequentially, and the third angle is greater than 90 degrees.

[0041] In addition, the lower mold includes: a lower mold base 1; a housing positioning fixture disposed on the lower mold base 1, the housing positioning fixture having a cavity in the middle for accommodating the battery housing; a cavity mold 22 disposed on the lower mold base 1 and coaxially arranged with the housing positioning fixture, for supporting the outer end of the battery terminal; and a support member disposed on the lower mold base and located outside the cavity mold, for supporting the outer end face of the battery housing. An elastic member is provided between the support member and the lower mold base 1.

[0042] The upper mold also includes: a mold mounting base 42 for mounting the punch; a pre-pressing block sleeved on the outside of the punch; and a telescopic connecting mechanism for mounting the pre-pressing block onto the mold mounting base 42, allowing the pre-pressing block to slide along the axial direction of the punch. Multiple mold mounting bases 42 are provided, each for mounting a different punch. The mold mounting base 42 is connected to an adapter. The outer diameter of the first portion of the mold mounting base 42 near the working end of the punch is smaller than that of the second portion away from the working end of the punch. The telescopic connecting mechanism includes: a sleeve sleeved on the outside of the first portion of the mold mounting base; a sliding sleeve sleeved on the outside of the punch and connected to the pre-pressing block, with at least a portion of the sliding sleeve located inside the sleeve; and a spring located between the first portion of the mold mounting base and the sleeve, with both ends abutting against the sliding sleeve and the mold mounting base 42 respectively.

[0043] Based on the above structure, a rivetless riveting method for a cylindrical battery casing includes the following steps:

[0044] Insert the battery terminals into the predetermined positions on the battery casing end caps from the outside;

[0045] The battery terminal is repeatedly pressed by a punch with different bevel angles at its working end to expand outwards until the expansion angle is greater than 90 degrees, so that the battery terminal is riveted to the battery housing. Example

[0046] Reference Figure 3 As shown, the rivetless riveting device for cylindrical battery casings of the present invention includes several forming parts: a lower mold base 1, a concave mold assembly 2, a cylindrical battery casing 3, and a convex mold assembly 4. Depending on the application, it can be configured as three machine bases. The lower mold base 1 is mounted on the machine base, and a riveting power source is mounted on the frame of the machine base. The convex mold assembly 4 is connected to the power source, and the power source drives the convex mold assembly 4 to close the mold with the concave mold assembly 2, thereby riveting the cylindrical battery casing.

[0047] In the above structure, the die assembly 2 is mounted on the lower die base 1. The die assembly 2 includes a housing positioning sleeve 21 and a die 22. The lower ends of both the housing positioning sleeve 21 and the die 22 are mounted on the lower die base 1, and the die 22 is located inside the housing positioning sleeve 21. The lower end of the cylindrical battery housing 3 is located inside the housing positioning sleeve 21, and the lower end face of the cylindrical battery housing 3 is in contact with the die 22. The punch assembly 4 includes a connecting component 41, a die mounting base 42, a pre-compression spring 43, a punch sleeve 44, a punch sliding sleeve 45, a pre-riveting die, a riveting die, and a shaping die. The die mounting base 42 is connected to the connecting component 41, and the punch sleeve 44... One end of the punch sleeve 44 is fitted onto the mold mounting base 42, and the other end of the punch sleeve 44 is slidably connected to the punch sliding sleeve 45. One end of the preload spring 43 abuts against the mold mounting base 42, and the other end of the preload spring 43 abuts against the punch sliding sleeve 45. The mold mounting base 42 is used to install the mold. The mold can be a pre-riveting mold, a riveting mold, and a shaping mold. The pre-riveting mold is used to pre-rive the cylindrical battery housing 3 when the punch assembly 4 and the die assembly 2 are closed. The riveting mold is used to rivet the cylindrical battery housing 3 when the punch assembly 4 and the die assembly 2 are closed. The shaping mold is used to shape the cylindrical battery housing 3 when the punch assembly 4 and the die assembly 2 are closed.

[0048] Reference Figure 2 As shown, the housing positioning sleeve 21 is a hollow cylinder, the die 22 is a cylinder, and the die 22 is locked on the lower die base 1 by fasteners. The die 22 is located at the center of the housing positioning sleeve 21.

[0049] In the above structure, a floating support block 23 is provided inside the housing positioning sleeve 21. A positioning post 231 is connected to the lower end of the floating support block 23. A positioning hole 11 is provided on the lower mold base 1. The positioning post 231 is disposed in the positioning hole 11 and can slide along the positioning hole 11. A floating spring 24 is provided between the floating support block 23 and the lower mold base 1. The floating spring 24 is used to provide axial floating during the riveting of the cylindrical battery housing 3. The cross-section of the floating support block 23 is annular. The housing positioning sleeve 21, the floating support block 23, and the die 22 are concentrically nested together in an order from the outside to the inside. The inner wall of the housing positioning sleeve 21 is provided with a first step 211 and a second step 212. The first step 211 is located above the second step 212. The lower end face of the cylindrical battery housing 3 is disposed on the first step 211. The first step 211 is used to limit the position of the cylindrical battery housing 3 inside the housing positioning sleeve 21. The outer wall of the floating support block 23 is provided with a first boss 232. When the first boss 232 contacts the second step 212, it is used to limit the floating position of the floating support block 23.

[0050] Reference Figure 3 , 4 As shown, the cylindrical battery housing 3 includes a battery outer shell 31, a first lower plastic part 32, a second lower plastic part 33, a sealing ring 34, an electrode post 35, and an upper plastic part 36. The cross-sectional area of ​​the first lower plastic part 32 is larger than that of the second lower plastic part 33. Both the first lower plastic part 32 and the second lower plastic part 33 are disposed on the inner bottom surface of the battery outer shell 31. The electrode post 35 is mounted on the bottom surface of the battery outer shell 31. The sealing ring 34 is disposed between the electrode post 35 and the through hole on the bottom surface of the battery outer shell 31. The upper plastic part 36 is mounted between the outer bottom surface of the battery outer shell 31 and the electrode post 35. The cylindrical battery housing 3 is placed inside the housing positioning sleeve 21. The battery outer shell 31 is cylindrical, and the lower outer wall of the battery outer shell 31 is disposed on the first boss 232. The end of the electrode post 35 extending out of the battery outer shell 31 is placed inside the concave mold 22. The upper end of the floating support block 23 is in contact with the lower end face of the battery outer shell 31. By sequentially operating the three sets of molds—pre-riveting mold, riveting mold, and shaping mold—the shape of the pole post 35 is changed, thereby riveting the second lower plastic part 33, sealing ring 34, pole post 35, and upper plastic part 36 together.

[0051] Reference Figure 5 As shown, the adapter assembly 41 includes a first adapter 411 and a second adapter 412. The second adapter 412 is locked to the first adapter 411. The mold mounting base 42 is sleeved on the outer wall of the second adapter 412. The outer wall of the mold mounting base 42 is provided with a third step 421, and the center of the mold mounting base 42 is provided with a first through hole 422. The inner wall of the first through hole 422 is provided with a fourth step 423. The pre-riveting mold, the riveting mold, and the shaping mold pass through the first through hole 422. One end of the preload spring 43 abuts against the third step 421.

[0052] In the above structure, the pre-riveting mold, riveting mold and forming mold are provided with a limiting end 461 at one end near the adapter assembly 41. The limiting end 461 is located inside the second adapter 412 and abuts against the fourth step 423.

[0053] In the above structure, the end of the punch sliding sleeve 45 extending out of the punch sleeve 44 is connected to a pre-pressing block 49. The lower end face of the pre-pressing block 49 is a plane, and the pre-pressing block 49 is used to press the first lower plastic part 32.

[0054] In the above structure, the center of the punch sliding sleeve 45 is provided with a second through hole 451, and the center of the pre-pressing block 49 is provided with a third through hole 491. The first through hole 422, the second through hole 451 and the third through hole 491 are on the same straight line. The pre-riveting mold, the riveting mold and the shaping mold pass through the first through hole 422, the second through hole 451 and the third through hole 491.

[0055] In the above structure, the punch sleeve 44 is cylindrical, and a fifth step 441 is provided on the inner wall of the punch sleeve 44. The punch sliding sleeve 45 is provided on the outer wall of one end of the punch sleeve 44, and a sixth step 452 is provided. The sixth step 452 abuts against the fifth step 441 to limit the punch sliding sleeve 45 within the punch sleeve 44. An annular gap is provided between the inner wall of the punch sleeve 44 and the mold mounting base 42. The preload spring 43 is located within the annular gap and is sleeved on the outside of the mold mounting base 42 located inside the punch sleeve 44.

[0056] Reference Figure 6 As shown, the initial pole post 35 has a circular base, a circular cylindrical structure on the circular base, and a circular groove in the center of the circular cylindrical structure.

[0057] Reference Figure 7 , 8 As shown, Figure 7 The middle part is a pre-riveting mold. A conical surface is provided at the lower end of the pre-riveting mold column. When the punch assembly 4 and the die assembly 2 are closed, the conical surface at the lower end of the pre-riveting mold is gradually pressed into the circular groove of the circular column structure, thereby pre-pressing the upper end of the circular groove into a flared conical groove. At the same time, an outwardly flared conical surface is formed around the top of the circular column structure.

[0058] Reference Figure 9 , 10 As shown, Figure 9 The middle part is the riveting mold. The lower end of the riveting mold is provided with a conical riveting pressing surface. The inclination angle of the conical surface of the riveting mold is greater than the angle of the conical surface at the lower end of the pre-riveting mold. When the punch assembly 4 and the die assembly 2 are closed, the riveting mold continues to press down on the conical surface formed by the pre-riveting mold above the circular cylindrical structure, so that the outward expansion angle of the conical surface formed above the circular cylindrical structure increases. The conical surface above the circular cylinder is close to parallel to the circular base, while retaining the lower part of the circular groove on the circular cylinder.

[0059] Reference Figure 11 , 12 As shown, Figure 11The forming mold has a concave conical surface at the bottom of its main body compared to the conical surface around the outer circumference of the pre-riveting mold and the riveting mold. At the same time, a small cylindrical structure is retained in the middle of the concave conical surface. When the punch assembly 4 and the die assembly 2 are closed, the small cylindrical structure extends into the lower end of the circular groove to shape the inner wall of the circular groove. Meanwhile, the concave conical surface continues to press down on the outwardly expanding conical surface of the riveting mold after riveting, causing the outwardly expanding conical surface to fold over to the side of the circular base.

[0060] Reference Figure 13 The image shown is a physical picture of the finished product after the actions of three sets of molds: pre-riveting mold, riveting mold, and shaping mold.

[0061] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A rivetless riveting device of a cylindrical battery case, characterized by, The application relates to a battery pole riveting device and a battery pole riveting method. The lower die is provided with a cavity for accommodating the battery shell and is used for fixing the battery shell from the bottom and the outer side; The upper die comprises a plurality of punches for extending into the battery shell to extrude the inner end of the battery pole and rivet the battery pole to the battery shell, wherein, The punch comprises a plurality of punches, and the working end of each punch is provided with a chamfer at the periphery, which is used for extruding the inner end of the battery pole to make the inner end of the battery pole expand outward by an angle, the angle being the angle of the position of the expanded inner end of the battery pole deviating from the original position; the plurality of punches make the inner end of the battery pole expand outward by angles which are sequentially increased, and at least one punch makes the inner end of the battery pole expand outward by an angle greater than 90 degrees; The punch comprises: A first punch, which is provided with a first chamfer at the periphery of the working end, and is used for extruding the inner end of the battery pole to make the inner end of the battery pole expand outward by a first angle; A second punch, which is provided with a second chamfer at the periphery of the working end, and is used for extruding the inner end of the battery pole to make the inner end of the battery pole expand outward by a second angle; A third punch, which is provided with a third chamfer at the periphery of the working end, and is used for extruding the inner end of the battery pole to make the inner end of the battery pole expand outward by a third angle; The first angle, the second angle and the third angle all refer to the angle of the position of the expanded inner end of the battery pole deviating from the original position, the first angle, the second angle and the third angle are sequentially increased, and the third angle is greater than 90 degrees.

2. The rivetless clinching apparatus of a cylindrical battery case according to claim 1, characterized by, The lower die comprises: A lower die base; A shell positioning tool arranged on the lower die base, the shell positioning tool is provided with the cavity for accommodating the battery shell in the middle; A concave die arranged on the lower die base and coaxially arranged with the shell positioning tool, which is used for supporting the outer end of the battery pole; A supporting piece arranged on the lower die base and located outside the concave die, which is used for supporting the outer end surface of the battery shell.

3. The rivetless clinching apparatus of a cylindrical battery case according to claim 2, characterized by, An elastic piece is arranged between the supporting piece and the lower die base.

4. The rivetless clinching apparatus of a cylindrical battery case according to claim 1, characterized by, The upper die further comprises: A die mounting base for mounting the punch; A pre-pressing block sleeved outside the punch; A telescopic connecting mechanism for mounting the pre-pressing block to the die mounting base, so that the pre-pressing block can slide axially along the punch.

5. The rivetless clinching apparatus of a cylindrical battery case according to claim 4, characterized by, The die mounting base has a plurality of die mounting bases for mounting a plurality of punches.

6. The rivetless riveting apparatus of a cylindrical battery case according to claim 4 or 5, characterized by The die mounting base is connected with an adapter.

7. The rivetless riveting apparatus of a cylindrical battery case according to claim 4, wherein The first part of the die mounting base close to the working end of the punch has a smaller outer diameter than the second part away from the working end of the punch, and the telescopic connecting mechanism comprises: A sleeve sleeved outside the first part of the die mounting base; A sliding sleeve sleeved outside the punch and connected with the pre-pressing block, at least a part of the sliding sleeve is located inside the sleeve; A spring located between the first part of the die mounting base and the sleeve, and the two ends of the spring abut against the sliding sleeve and the die mounting base respectively.

8. A rivetless riveting method of a cylindrical battery case, characterized by, The application relates to a battery pole riveting device and a battery pole riveting method. The battery pole is inserted into the predetermined position of the end cover of the battery shell from the outer side; The convex die with different guide angles is used to extrude the one end of the battery pole inside the battery shell for multiple times, so that the inner end of the battery pole is unfolded outwardly in sequence until the unfolded angle is greater than 90 degrees, and the battery pole is riveted to the battery shell; The convex die includes a first convex die, a second convex die and a third convex die, and the step of extruding the one end of the battery pole inside the battery shell for multiple times so that the inner end of the battery pole is unfolded outwardly in sequence includes: The first convex die is used to extrude the inner end of the battery pole so that the inner end of the battery pole is unfolded outwardly by a first angle; The second convex die is used to extrude the inner end of the battery pole so that the inner end of the battery pole is unfolded outwardly by a second angle; The third convex die is used to extrude the inner end of the battery pole so that the inner end of the battery pole is unfolded outwardly by a third angle; The first angle, the second angle and the third angle all refer to the angle of the unfolded inner end of the battery pole deviating from the original position, the first angle, the second angle and the third angle increase in sequence, and the third angle is greater than 90 degrees.

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