Manufacturing method of copper-aluminum composite connecting block, secondary battery top cover and secondary battery

Abstract

The invention discloses a manufacturing method of a copper-aluminum composite connecting block, a secondary battery top cover and a secondary battery. The manufacturing method comprises the following steps: firstly, placing a copper bar in a thermal forming mold; the softened or molten aluminum material is pressed into the thermal forming mold, so that the copper bar is covered with the aluminum material, and the compactness of the aluminum material is kept through rolling or forging and pressing; and finally, cutting the formed strip-shaped composite material to form the required connecting block. The copper-aluminum composite material is tightly combined, and the compactness of the aluminum material can be guaranteed.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a method for manufacturing a copper-aluminum composite connecting block, a secondary battery top cover, and a secondary battery. Background Art

[0002] Secondary batteries are widely used in people's daily lives as energy storage carriers or to provide energy for electrical equipment, such as electric vehicles and energy storage projects. Secondary batteries generally include a metal shell, a battery cell encapsulated in the shell, an electrolyte, and a battery cover that seals the shell and leads out the electrodes. The battery cover has various structural forms, and its performance meets the requirements of sealing and explosion-proof. A battery cover structure that has been used for a long time is a riveted block method, which includes a cover plate with a pole hole formed through it, an outer insulating member located on the upper side of the cover plate, a riveted block located above the outer insulating member, an inner insulating member attached to the lower side of the cover plate, and a pole that passes through the cover plate and the riveted block from the bottom of the cover plate and is riveted to the riveted block. The top of the pole is fixed to the riveted block by riveting, and a sealing ring is clamped between the pole and the cover plate for sealing.

[0003] The above solution has problems such as heavy weight, high cost, and easy cracking of the external insulating parts caused by riveting. For example, the weight of the riveted block plus the pole is not conducive to battery weight reduction, and the separate pole solution also requires riveting and welding processes, which has the problem of high material cost and processing cost. Patent No. 202420844581.6 of the People's Republic of China discloses a battery top cover solution for weight reduction, which adopts a bipolar column solution of upper pole and lower pole. The upper pole is recessed downward to form a first groove, and the lower pole is recessed upward to form a second groove. The bottom and top surfaces of the first groove and the second groove are fixed by bonding or welding. Although this structure reduces weight to a certain extent, the welding of its bipolar column requires penetrating one of the poles to avoid welding, and the welding effect is not good. At the same time, the lower pole needs to be welded with a connecting piece to electrically connect to the battery cell. Summary of the Invention

[0004] In view of this, it is necessary to provide a method for manufacturing a copper-aluminum composite connecting block with good copper-aluminum bonding strength and simple process, a secondary battery top cover and a secondary battery.

[0005] In order to solve the above technical problems, the present application provides a method for manufacturing a copper-aluminum composite connecting block, which comprises first placing a copper bar in a hot forming mold; then pressing softened or molten aluminum into the hot forming mold so that the aluminum covers the copper bar and maintaining the density of the aluminum by rolling or forging; finally, cutting the formed strip-shaped composite material to form the required connecting block.

[0006] Preferably, the copper bar is pre-stamped to form a plurality of spaced poles, and then the copper bar is placed in the thermoforming mold, the thermoforming mold includes a first mold and a second mold spliced ​​together, the spliced ​​thermoforming mold includes a concave first cavity and a plurality of second cavities that continue to be concave downward from the first cavity, the poles on the copper bar are recessed in the second cavities, and the portion of the copper bar other than the poles is supported on the bottom surface of the first cavity.

[0007] Preferably, the softened or molten aluminum fills the first cavity and covers the copper bar. The two are tightly bonded by cooling the aluminum, and the density of the aluminum is maintained by pressure. Finally, the copper-aluminum composite strip is cut to obtain a connection block with a pole formed at the same time.

[0008] Preferably, the junction of the first mold and the second mold passes through the second cavity, that is, the second cavity is formed by splicing the first mold and the second mold, which is conducive to demoulding of the composite material.

[0009] In order to solve the above technical problems, the present application also provides a secondary battery top cover, including the above-mentioned connecting block, a cover plate with a pole hole formed therethrough, an inner insulating part attached to the lower surface of the cover plate, an outer insulating part attached to the upper surface of the cover plate, a conductive sheet attached to the inner insulating part and a sealing ring, the bottom of the connecting block protrudes downward to form a pole, the pole includes a first column and a second column with smaller outer diameters from top to bottom, the sealing ring includes an inner ring body clamped between the bottom surface of the connecting block and the conductive sheet and an outer ring body clamped between the bottom surface of the cover plate and the conductive sheet, a fixing hole for the second column to pass through is provided in the middle of the conductive sheet, the upper side limit of the conductive sheet is located on the bottom surface of the first column, and the second column is welded and fixed together at the junction with the fixing hole.

[0010] Preferably, the external insulating member includes an isolation plate body attached to the upper surface of the cover plate, an outer wall protruding upward from the periphery of the isolation plate body to partially surround the outer edge of the connecting block, and a through hole formed through the isolation plate body, the periphery of the through hole protrudes downward to form a lower edge ring body, the lower edge ring body is pressed into the inner side of the pole hole of the cover plate, there is a gap between the lower edge ring body and the first column, and the top end of the inner ring body of the sealing ring is inserted into the gap between the lower edge ring body and the first column.

[0011] Preferably, the inner insulating part includes a fitting body fitted on the lower surface of the cover plate, a through hole formed through the fitting body, and a receiving cavity formed on the bottom surface of the fitting body for receiving the conductive sheet, a surrounding wall is formed on the outer periphery of the receiving cavity, the outer ring body of the sealing ring is located between the inner wall surface of the through hole and the outer surface of the first cylinder in the radial direction, and the outer ring body is clamped between the conductive sheet and the lower surface of the cover plate in the vertical direction.

[0012] In order to solve the above technical problems, the present application also provides a secondary battery top cover, including a connecting block manufactured by the above method, a cover plate with a pole hole formed through it, an inner insulating part attached to the lower surface of the cover plate, an outer insulating part attached to the upper surface of the cover plate, a conductive sheet attached to the inner insulating part and a sealing ring, the bottom of the connecting block protrudes downward to form a pole, and the pole includes, from top to bottom, a first column, a third column and a second column with decreasing outer diameter, the bottom surface of the first column is flush with the bottom surface of the cover plate, the sealing ring is clamped in the vertical direction between the bottom surface of the first column, the bottom surface of the cover plate and the upper surface of the conductive sheet, a fixing hole for the second column to pass through is provided in the middle of the conductive sheet, the upper side limit of the conductive sheet is located on the bottom surface of the third column, and the second column is welded and fixed together at the junction of the fixing hole.

[0013] Preferably, the outer insulating member includes an isolation plate body affixed to the upper surface of the cover plate, an outer wall protruding upward from the periphery of the isolation plate body to partially surround the outer edge of the connecting block, and a through hole formed through the isolation plate body, the periphery of the through hole protruding downward to form a lower edge ring body, the lower edge ring body is pressed into the inner side of the pole hole of the cover plate, and the lower edge ring body is affixed to the outer peripheral surface of the first column.

[0014] Preferably, the inner insulating part includes a fitting body fitted on the lower surface of the cover plate, a through hole formed through the fitting body, and a receiving cavity formed on the bottom surface of the fitting body for receiving the conductive sheet, a surrounding wall is formed on the outer periphery of the receiving cavity, the sealing ring is located between the inner wall surface of the through hole and the outer surface of the third cylinder in the radial direction, and the upper surface of the sealing ring is pressed against the bottom surface of the cover plate and the bottom surface of the first cylinder in the radial direction, the lower surface of the sealing ring is pressed against the upper surface of the conductive sheet, and the sealing ring is clamped by applying a clamping force through the bottom surface of the cover plate, the bottom surface of the first cylinder and the surface of the conductive sheet to achieve sealing.

[0015] Preferably, the conductive sheet includes a sheet body, the fixing hole is formed through the sheet body, the bottom surface of the sheet body is located at the periphery of the fixing hole and is recessed upward to form a concave ring, the bottom surface of the second column is flush with the bottom surface of the concave ring, and the second column and the fixing hole are welded at the joint gap, and the weld produced by the welding does not exceed the height of the concave ring downward, that is, does not exceed the lower surface of the sheet body.

[0016] Preferably, the cover plate is located on both sides of the pole hole and is stamped downward to form a first positioning structure, the first positioning structure includes a first positioning recessed portion recessed from the upper surface of the cover plate and a first positioning protrusion protruding from the lower surface of the cover plate, the inner insulating member is recessed downward corresponding to the first positioning protrusion to form a second positioning structure, the second positioning structure includes a second positioning recess for the first positioning protrusion to be snapped into and a second positioning protrusion protruding from the bottom surface of the inner insulating member, the outer insulating member is protruded on the first positioning recess to form a third positioning protrusion snapped into the first positioning recess, and the conductive sheet is provided with a third positioning recess at the position corresponding to the second positioning protrusion.

[0017] In order to solve the above technical problems, the present application also provides a secondary battery, comprising a shell, a battery cell unit encapsulated in the shell and the aforementioned secondary battery top cover, wherein the secondary battery top cover is used to seal the shell.

[0018] The manufacturing method of the copper-aluminum composite connecting block of the present application directly utilizes the characteristic that the melting point of copper is higher than that of aluminum. The softened or molten aluminum is directly pressed onto the copper bar to form the copper-aluminum composite material. The high-temperature forming makes the bond between the two closer. In particular, pre-forming the poles on the copper bar can eliminate the need to stamp the connecting block again to form the poles, and forming the poles with thinner copper bars is simpler.

[0019] The secondary battery top cover of the present application directly forms the poles on the connecting block. Compared with the technical solution in the prior art in which independent poles are riveted to the connecting block, it can effectively reduce product costs and is simple to assemble. It only requires a welding process to achieve it. Compared with the solution in the prior art of first riveting and then welding, it can greatly reduce the process cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Example 1

[0022] Figure 1 This is a three-dimensional diagram of the secondary battery top cover of Example 1 of the present application;

[0023] Figure 2 This is a three-dimensional exploded view of the secondary battery top cover of Example 1 of the present application;

[0024] Figure 3 For the Figure 2 A cross-sectional view taken along the dashed line AA is shown;

[0025] Figure 4 A three-dimensional diagram of the outer insulating member of the secondary battery top cover according to the first embodiment of the present application;

[0026] Figure 5 A three-dimensional view of the inner insulating member of the secondary battery top cover of the first embodiment of the present application

[0027] Figure 6 For the Figure 1 A cross-sectional view taken along the dashed line BB shown;

[0028] Example 2

[0029] Figure 7 This is a three-dimensional exploded view of the secondary battery top cover of Example 2 of the present application;

[0030] Figure 8 A three-dimensional diagram of a connecting block of a secondary battery top cover according to a second embodiment of the present application;

[0031] Figure 9 For the Figure 8 A cross-sectional view taken along the dotted line CC is shown;

[0032] Figure 10 This is a cross-sectional view of a secondary battery top cover according to the second embodiment of the present application;

[0033] Example 3

[0034] Figure 11 This is a schematic diagram of a metal plate according to a third embodiment of the present application;

[0035] Figure 12 For the Figure 11 A cross-sectional view taken along the dashed line DD shown;

[0036] Example 4

[0037] Figures 13 to 15 This is a schematic diagram of the thermoforming process of the connecting block of Example 4 of the present application.

[0038] Description of Reference Numerals

[0039] Cover plate 10; pole hole 11; first positioning structure 12; first positioning recess 121; first positioning protrusion 122; connecting block 20; aluminum layer 21; copper layer 22; pole 23; recess 24; plate body 25; first column 201; second column 202; third column 203; plate bottom 231; first step 232; pole bottom 233; second step 234; outer insulator 30; isolation plate 31; outer wall 32; accommodating cavity 33; through hole 34; lower edge ring 35 ; Third positioning protrusion-36; Conductive sheet-40; Sheet body-41; Fixing hole-42; Third positioning recess-43; Recessed ring-44; Inner insulating part-50; Fitting body-51; Through hole-52; Second positioning structure-53; Second positioning recess-531; Second positioning protrusion-532; Surrounding wall-54; Accommodating cavity-55; Sealing ring-60; Inner ring body-61; Sealing hole-62; Outer ring body-63; Thermoforming mold-70; First mold-701, second mold-702; First cavity-71; Second cavity-72; Joint seam-73. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions and advantages of this application more clear, the technical solutions of this application will be described clearly and completely below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this application, not all of them.

[0041] This application is based on Figure 1 The X direction is the horizontal direction, the Y direction is the longitudinal direction, and the Z direction is the vertical direction upward.

[0042] Example 1

[0043] See also Figures 1 to 6 As shown, the secondary battery top cover of this embodiment includes a cover plate 10, an inner insulating member 50 attached to the lower surface of the cover plate 10, an outer insulating member 30 attached to the upper surface of the cover plate 10, a connecting block 20 mounted on the outer insulating member 30 and integrally formed with a pole 23, a conductive sheet 40 placed on the inner insulating member 50 and welded to the pole 23 of the connecting block 20, and a sealing ring 60 clamped between the cover plate 10, the pole 23 and the conductive sheet 40.

[0044] Please refer to Figure 2 、 Figure 3As shown, the cover plate 10 is made of one of aluminum alloy, stainless steel, or titanium alloy. If stainless steel or titanium alloy is used, the cover plate 10 is thinner, while aluminum alloy allows for a thicker cover plate. Stainless steel and titanium alloy have higher melting points, offering improved safety. However, stainless steel is more difficult to process than aluminum alloy, making it difficult to fabricate complex structures on the cover plate 10, which would otherwise increase manufacturing costs. Titanium alloy, on the other hand, is more difficult to process and has higher material costs, and is generally used in the aviation field. Aluminum alloy is currently widely used in automotive power batteries and energy storage batteries. However, due to its low melting point, it can easily burn through and destroy the entire battery pack in a short period of time if a fire occurs, resulting in a short explosion time and insufficient escape time for vehicle occupants. Stainless steel, on the other hand, not only reduces material costs and improves space utilization, but also improves product safety, extending the duration of a large-scale fire or explosion, providing more time for occupants to escape.

[0045] The cover plate 10 includes a through-hole 11 and first positioning structures 12 stamped downwardly on both sides of the hole 11 in the transverse direction. The first positioning structure 12 includes a first positioning recess 121 recessed inward from the upper surface of the cover plate 10 and a first positioning protrusion 122 protruding from the lower surface of the cover plate 10. The first positioning recess 121 and the first positioning protrusion 122 are stamped simultaneously on the outer and inner sides of the first positioning structure 12.

[0046] The conductive sheet 40 is stamped from a copper alloy sheet and includes a sheet body 41, a fixing hole 42 formed vertically through the sheet body 41, and third positioning recesses 43 stamped laterally on either side of the fixing hole 42. The third positioning recesses 43 are formed on the upper surface of the sheet body 41. The lower surface of the sheet body 41 is flat and has no protrusions. The third positioning recesses 43 are open laterally to form a notched circular shape. The lower surface of the sheet body 41 is recessed upward to form a concave ring 44 around the fixing hole 42. The bottom surface of the concave ring 44 is higher than the bottom surface of the sheet body 41.

[0047] Key References Figure 2 、 Figure 3 、 Figure 5As shown, the inner insulating member 50 includes a fitting body 51 fitted to the lower surface of the cover plate 10, a through hole 52 formed through the fitting body 51, second positioning structures 53 formed on both sides of the through hole 52, and a receiving cavity 55 formed on the lower surface of the fitting body 51 and enclosing the through hole 52. The second positioning structure 53 includes a second positioning recess 531 formed downwardly from the upper surface of the fitting body 51 and a second positioning protrusion 532 protruding from the lower surface of the fitting body 51. The second positioning protrusion 532 is also enclosed within the receiving cavity 55. The receiving cavity 55 is formed by a surrounding wall 54 protruding from the lower surface of the fitting body 51, and the lower surface of the second positioning protrusion 532 does not extend beyond the bottom surface of the surrounding wall 54. The conductive sheet 40 is pressed into the receiving cavity 55. The periphery of the conductive sheet 40 is restrained by the surrounding wall 54. The third positioning recess 43 of the conductive sheet 40 engages with the second positioning protrusion 532 to prevent rotation. The second positioning protrusion 532 is integrally connected to the surrounding wall 54 to enhance the strength of the second positioning protrusion 532.

[0048] Please continue reading Figures 2 to 4 As shown, the outer insulating member 30 includes an isolation plate 31, an outer peripheral wall 32 protruding upward from the upper surface of the isolation plate 31, a receiving cavity 33 enclosed by the isolation plate 31 and the outer peripheral wall 32, and a through hole 34 formed through the isolation plate 31. A third positioning protrusion 36 protrudes downward from the bottom surface of the isolation plate 31, and a lower edge ring 35 extends downward from the edge of the through hole 34.

[0049] The sealing ring 60 includes an inner ring body 61, an outer ring body 63 extending radially outward from the lower side of the inner ring body 61, and a sealing hole 62 formed through the inner ring body 61. The outer diameter of the outer ring body 63 is larger than the outer diameter of the inner ring body 61, and the inner ring body 61 is formed by protruding upward from the upper surface of the outer ring body 63.

[0050] The connecting block 20 includes a plate portion 25 and a downwardly protruding terminal post 23 formed by stamping or stretching downward from the center of the plate portion 25. When the connecting block 20 serves as the negative electrode, it must include a copper layer welded to the conductive sheet 40 and an aluminum layer exposed outside the cover plate 10. Specifically, the connecting block 20 must include both copper and aluminum layers. When the connecting block 20 serves as the positive electrode, it only needs to be made of aluminum.

[0051] The connecting block 20 of this embodiment is introduced in detail by taking the negative electrode as an example. The connecting block 20 includes an aluminum layer 21 located on the upper side and a copper layer 22 attached to the lower side of the aluminum layer 21. Before the pole 23 is stamped, the connecting block 20 is a flat plate structure. After stamping, the pole 23 is formed by being recessed downward from the middle part of the connecting block 20. The pole 23 includes a first column 201 and a second column 202 with gradually decreasing outer diameters from top to bottom. The bottom surface of the connecting block 20 is defined as the bottom surface 231 of the plate, the bottom surface of the first column 201 is defined as the first step surface 232, and the bottom surface of the second column 202 is defined as the pole bottom surface 233. When the pole 23 is stamped, a pit 24 is formed at the corresponding stamping position of the connecting block 20, and the outer surface of the pole 23 is wrapped by the copper layer 22.

[0052] Key References Figure 6 As shown, the following will focus on the assembly method of the secondary battery top cover of this embodiment:

[0053] First, assemble the outer insulating member 30 on the outer surface of the cover plate 10, the third positioning protrusion 36 of the outer insulating member 30 enters the first positioning recess 121 on the outer surface of the cover plate 10, and the lower edge ring body 35 is snapped into the edge of the pole hole 11; fit the inner insulating member 50 on the inner surface of the cover plate 10, and fix it to the inner surface of the cover plate 10 by snapping or bonding, and the first positioning protrusion 122 enters the second positioning recess 531 on the surface of the inner insulating member 50 for positioning. The inner diameter of the through hole 52 of the inner insulating member 50 is much larger than the pole hole 11 of the cover plate 10 so that at least part of the inner surface of the cover plate 10 within the range of the through hole 52 is exposed outside the inner insulating member 50; the stamped connecting block 20 is positioned on the outer insulating member 20, and the plate body 25 of the connecting block 20 is at least partially surrounded by the accommodating cavity 33, and the pole 23 passes through the through hole 34, the pole hole 11 and the through hole 52; the sealing ring 60 is inserted from the inside to the outside of the pole 23, and the top of the inner ring body 61 is against the bottom surface 231 of the plate body at the periphery of the pole 23 and wraps the outer periphery of the first column 201, the outer ring body 63 is located within the range of the through hole 52 of the inner insulating member 50 and the upper surface of the outer ring body 63 is in contact with the inner surface of the cover plate 10; finally, the sheet body of the conductive sheet 40 is installed into the inner In the receiving cavity 55 on the bottom surface of the insulating part 50, the second positioning protrusion 532 of the inner insulating part 50 is inserted into the third positioning recess 43 of the conductive sheet 40, and the bottom surface of the outer ring body 63 of the sealing ring 60 is supported on the upper surface of the conductive sheet 40. The second column 202 is inserted into the fixing hole 42 of the conductive sheet 40, and the upper surface of the conductive sheet 40 is limited to the first step surface 232 defined by the bottom surface of the first column 201. The conductive sheet 40 and the connecting block 20 are pressed tightly so that the bottom surface of the concave ring 44 of the conductive sheet 40 is flush with the bottom surface 233 of the pole defined by the bottom surface of the second column 202. At this time, the inner ring body 61 of the sealing ring 60 is squeezed and clamped by the conductive sheet 40 and the bottom surface 231 of the plate body, and the outer ring body 63 is squeezed and clamped by the inner surface of the cover plate 10 and the conductive sheet 40. The outer contour of the conductive sheet 40 is consistent with the receiving cavity 55 of the inner insulating member 50, so that the conductive sheet 40 is confined within the receiving cavity 55. After the connecting block 20 and the conductive sheet 40 are pressed together, continuous welding is performed at the joint between the conductive sheet 40 and the second column 202 to fix the connecting block 20 and the conductive sheet 40 together and form a welding ring S.

[0054] In this embodiment, the inner ring body 61 of the sealing ring 60 realizes the sealing between the bottom surface 231 of the plate body of the connecting block 20 and the surface of the conductive sheet 40, and the outer ring body 63 realizes the sealing between the inner surface of the cover plate 10 and the surface of the conductive sheet 40, thereby achieving double waterproofing, and waterproofing no longer depends on the welding sealing of the welding ring S.

[0055] This embodiment forms the pole 23 by directly stamping and stretching downward on the connecting block 20. Compared with the technical solution in the prior art in which an independent pole is riveted to the connecting block 20, this embodiment can effectively reduce product costs and is simple to assemble, requiring only a welding process. Compared with the solution in the prior art in which riveting is performed first and then welding, this embodiment can greatly reduce process costs.

[0056] Example 2

[0057] See also Figures 7 to 10 As shown, the difference between this embodiment and the first embodiment is that: first, the bottom surface of the connecting block 20 adopts a solution of a partial composite copper layer 22, that is, the copper layer 22 is set only on the bottom surface of the area where the pole 23 needs to be stamped, and the rest of the plate portion 25 of the connecting block 20 is made of aluminum. The provision of the copper layer 22 in some areas can effectively reduce the use of copper and reduce material costs; at the same time, the solution of copper plating in some areas is also applicable to the first embodiment. Secondly, the structure of the pole 23 is different from that of the first embodiment. The pole 23 of this embodiment is further provided with a third column 203 between the first column 201 and the second column 202, and the bottom surface of the first column 201 outside the third column 203 is defined as a second step surface 234. During assembly, the plate bottom surface 231 is crimped onto the isolation plate 31 of the outer insulator 30, and the lower edge ring 35 of the outer insulator 30 is affixed to the outer circumference of the first column 201. No gap is left between the lower edge ring 35 and the outer circumference of the first body 201 to accommodate the inner ring 61 of the sealing ring 60. In this embodiment, the sealing ring 60 eliminates the upwardly extending inner ring 61 and includes only an outer ring 63 and a sealing hole 62 extending through the outer ring 63. The upper surface of the outer ring 63 radially affixes to the second stepped surface 234 of the pole 23 and the inner surface of the cover plate 10. The lower edge ring 35 is located between the first column 201 and the inner side of the pole hole 11 of the cover plate 10, and above the outer ring 63.

[0058] The remaining structures of Example 2 are basically the same as those of Example 1. The design of the concave ring 44 of the conductive sheet 40 in Examples 1 and 2 is used to ensure that the weld joint between the conductive sheet 40 and the second column 202 is performed within the concave ring 44, and the weld point formed during welding does not protrude beyond the bottom surface of the sheet body 41 of the conductive sheet 40, so that the bottom surface of the sheet body 41 remains smooth and flat.

[0059] In the second embodiment, a third column 203 is processed on the pole 23, and the bottom surface of the first column 201 outside the third column 203 is clamped with the sealing ring 60 to achieve waterproofing, without extending the sealing ring upward to form an inner ring body 61 to clamp on the bottom surface 231 of the plate body. The height of the sealing ring is lowered in the vertical direction, so that the clamping and pressing effect is better and the waterproof performance is better.

[0060] Example 3

[0061] See also Figure 11 、 Figure 12 As shown, the copper-clad forming method of the connection block 20 of the present application first lays the formed copper strip in the forming equipment, then places the molten, semi-solid or softened aluminum material outside the copper strip, and forms a composite strip of copper and aluminum by extrusion molding. Finally, a plurality of the poles 23 are continuously stamped on the composite strip, and finally cut to form the connection block 20. The melting point of the copper material is higher than that of the aluminum material. During molding, the high-temperature softening of the aluminum material will not cause the copper material to melt and affect the shape of the copper material, but the softened aluminum material and the copper material bonding surface will maintain good bonding. The copper material can occupy the entire bottom surface or only a portion of the area and be surrounded by the aluminum material on three sides.

[0062] Example 4

[0063] See also Figures 13 to 15 As shown, this embodiment includes a thermoforming mold 70, which includes a first mold 701 and a second mold 702 that are spliced ​​together, and a joint 73 between the first and second molds 701 and 702. The spliced ​​thermoforming mold 70 includes a first cavity 71 and a plurality of second cavities 72 that are recessed downward from the surface of the first cavity 71. The joint 73 is located at the location of the second cavity 72, which corresponds to the pole 23 of the connecting block 20.

[0064] In this embodiment, the copper strip is first punched to form a plurality of poles 23 (eg Figure 13 Then the formed copper strip is placed in the thermoforming mold 70, and the plurality of poles 23 on the copper strip are pressed into the second cavity 72, and the rest of the copper strip is supported on the surface of the first cavity 71 (as shown). Figure 14 Then the softened aluminum is pressed into the first cavity 71 and filled with the pole 23 of the copper bar, and then the softened or cooled aluminum is roll-formed to obtain the aluminum layer 21 (as shown); Figure 15Finally, the first mold 701 and the second mold 702 are disassembled to obtain a copper-aluminum composite strip, which is then cut to obtain the connecting block 20. The pit 24 can be formed during rolling or can be replaced with a flat structure by eliminating the pit 24.

[0065] When the connecting block 20 of the present application is used as a negative electrode, a copper-aluminum composite process is used, which greatly reduces the use of copper materials.

[0066] The present application also includes a secondary battery, which includes a shell, a battery cell unit encapsulated in the shell, and a secondary battery top cover that closes the shell and is electrically connected to the battery cell unit.

[0067] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above embodiments merely represent preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for manufacturing a copper-aluminum composite connecting block, characterized in that: First, place the copper strip in a thermoforming mold; then press the softened or molten aluminum into the thermoforming mold so that the aluminum covers the copper strip and maintain the density of the aluminum through rolling or forging; finally, cut the formed strip composite material into the required connecting blocks.

2. The method for manufacturing the copper-aluminum composite connecting block according to claim 1, wherein: The copper bar is pre-stamped to form a plurality of spaced poles, and then the copper bar is placed in the thermoforming mold. The thermoforming mold includes a first mold and a second mold spliced ​​together. The spliced ​​thermoforming mold includes a concave first cavity and a plurality of second cavities that continue to be concave downward from the first cavity. The poles on the copper bar are recessed in the second cavities, and the portion of the copper bar other than the poles is supported on the bottom surface of the first cavity.

3. The method for manufacturing the copper-aluminum composite connecting block according to claim 2, wherein: The softened or molten aluminum fills the first cavity and covers the copper bar. The aluminum is cooled to tightly bond the two together, and pressure is used to maintain the compactness of the aluminum. Finally, the copper-aluminum composite bar is cut to obtain a connection block with a pole formed thereon.

4. The method for manufacturing the copper-aluminum composite connecting block according to claim 3, wherein: The joint of the first mold and the second mold passes through the second cavity, that is, the second cavity is formed by splicing the first mold and the second mold, which is conducive to demoulding of the composite material.

5. A secondary battery top cover, characterized in that: It includes a connecting block manufactured by the method according to claim 1, a cover plate with a pole hole formed therethrough, an inner insulating part attached to the lower surface of the cover plate, an outer insulating part attached to the upper surface of the cover plate, a conductive sheet attached to the inner insulating part and a sealing ring, the bottom of the connecting block protrudes downward to form a pole, the pole includes a first column and a second column with a smaller outer diameter from top to bottom, the sealing ring includes an inner ring body clamped between the bottom surface of the connecting block and the conductive sheet and an outer ring body clamped between the bottom surface of the cover plate and the conductive sheet, a fixing hole for the second column to pass through is provided in the middle of the conductive sheet, the upper side limit of the conductive sheet is located on the bottom surface of the first column, and the second column is welded and fixed together at the junction with the fixing hole.

6. The secondary battery top cover according to claim 5, wherein: The outer insulating member includes an isolation plate body attached to the upper surface of the cover plate, an outer wall protruding upward from the periphery of the isolation plate body to partially surround the outer edge of the connecting block, and a through hole formed through the isolation plate body, the periphery of the through hole protrudes downward to form a lower edge ring body, the lower edge ring body is pressed into the inner side of the pole hole of the cover plate, there is a gap between the lower edge ring body and the first column, and the top end of the inner ring body of the sealing ring is inserted into the gap between the lower edge ring body and the first column.

7. The secondary battery top cover according to claim 6, wherein: The inner insulating part includes a fitting body fitted on the lower surface of the cover plate, a through hole formed through the fitting body, and a receiving cavity formed on the bottom surface of the fitting body for receiving the conductive sheet, a surrounding wall is formed on the outer periphery of the receiving cavity, the outer ring body of the sealing ring is located between the inner wall surface of the through hole and the outer surface of the first cylinder in the radial direction, and the outer ring body is clamped between the conductive sheet and the lower surface of the cover plate in the vertical direction.

8. A secondary battery top cover, characterized in that: The invention comprises a connecting block manufactured by the method according to claim 1, a cover plate with a pole hole formed therethrough, an inner insulating member attached to the lower surface of the cover plate, an outer insulating member attached to the upper surface of the cover plate, a conductive sheet attached to the inner insulating member and a sealing ring, the bottom of the connecting block protrudes downward to form a pole, the pole comprises, from top to bottom, a first column, a third column and a second column with decreasing outer diameter, the bottom surface of the first column is flush with the bottom surface of the cover plate, the sealing ring is clamped in the vertical direction between the bottom surface of the first column, the bottom surface of the cover plate and the upper surface of the conductive sheet, a fixing hole for the second column to pass through is provided in the middle of the conductive sheet, the upper side limit of the conductive sheet is located on the bottom surface of the third column, and the second column is welded and fixed together at the junction with the fixing hole.

9. The secondary battery top cover according to claim 8, wherein: The outer insulating member includes an isolation plate body attached to the upper surface of the cover plate, an outer wall protruding upward from the periphery of the isolation plate body to partially surround the outer edge of the connecting block, and a through hole formed through the isolation plate body, the periphery of the through hole protruding downward to form a lower edge ring body, the lower edge ring body is pressed into the inner side of the pole hole of the cover plate, and the lower edge ring body is attached to the outer peripheral surface of the first column.

10. The secondary battery top cover according to claim 9, wherein: The inner insulating part includes a fitting body fitted on the lower surface of the cover plate, a through hole formed through the fitting body, and a receiving cavity formed on the bottom surface of the fitting body for receiving the conductive sheet, a surrounding wall is formed on the outer periphery of the receiving cavity, the sealing ring is located between the inner wall surface of the through hole and the outer surface of the third cylinder in the radial direction, and the upper surface of the sealing ring is pressed against the bottom surface of the cover plate and the bottom surface of the first cylinder in the radial direction, and the lower surface of the sealing ring is pressed against the upper surface of the conductive sheet, and the sealing ring is clamped by applying a clamping force through the bottom surface of the cover plate, the bottom surface of the first cylinder and the surface of the conductive sheet to achieve sealing.

11. The secondary battery top cover according to claim 7 or 10, wherein: The conductive sheet includes a sheet body, the fixing hole is formed through the sheet body, the bottom surface of the sheet body is located at the periphery of the fixing hole and is recessed upward to form a concave ring, the bottom surface of the second column is flush with the bottom surface of the concave ring, and the second column is welded at the joint gap with the fixing hole, and the welding point produced by the welding does not exceed the height of the concave ring downward, that is, does not exceed the lower surface of the sheet body.

12. The secondary battery top cover according to claim 11, wherein: The cover plate is located on both sides of the pole hole and is stamped downward to form a first positioning structure. The first positioning structure includes a first positioning recessed portion recessed from the upper surface of the cover plate and a first positioning protrusion protruding from the lower surface of the cover plate. The inner insulating member is recessed downward corresponding to the first positioning protrusion to form a second positioning structure. The second positioning structure includes a second positioning recess for the first positioning protrusion to be snapped into and a second positioning protrusion protruding from the bottom surface of the inner insulating member. The outer insulating member is protruded on the first positioning recess to form a third positioning protrusion that is snapped into the first positioning recess. The conductive sheet is provided with a third positioning recess at a position corresponding to the second positioning protrusion.

13. A secondary battery, characterized in that: The battery comprises a shell, a battery cell unit encapsulated in the shell, and a secondary battery top cover as claimed in claim 5 or 8, wherein the secondary battery top cover is used to seal the shell.

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