Connection method and structure of battery cell tabs and cover plate

Abstract

This invention provides a method and structure for connecting a battery cell tab to a cover plate. The connection method includes the following steps: First, riveting holes for the tab and the cover plate are machined; then, the riveting holes for the tab and the cover plate are pre-aligned; next, the device is placed on a riveting machine, and the riveting head is aligned with the riveting holes for the tab and the cover plate; then, a riveting component is installed on the riveting head, wherein the riveting component has an opening at one end of the riveting head and is in the form of a thin-walled tube. The riveting head drives the riveting component downward, so that the end of the riveting component contacts the bottom of the riveting hole in the cover plate. Then, the riveting head continues to press down, gradually expanding the end of the riveting component outward to form an end-limiting flange; finally, after the riveting head is in place, the end-limiting flange is pressed tightly onto the tab, completing the connection between the tab and the cover plate. The method for connecting the battery cell tab and the cover plate of this invention is beneficial for improving production cycle time and battery cell quality, and can also reduce equipment footprint and investment, and has excellent performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery cell manufacturing, in particular to a method for connecting a battery cell tab and a cover plate. BACKGROUND

[0002] In the prior art, the lithium battery cell tab and the top cover are connected by laser welding. In order to ensure the current flow area between the tab and the top cover, the welding area cannot be reduced, so the welding time of each cell by a single laser stabilizes at 2-3 seconds and cannot be further improved, which poses a dilemma for production line yield increase and efficiency improvement. Only the number of lasers can be simply increased to solve the problem. In addition, the laser welding time is difficult to reduce, and the process cycle is difficult to improve. During laser welding, spatter, smoke, and foreign particles are generated, which requires a complex dust removal system. If not properly controlled, foreign matter may enter the battery cell, which will seriously affect the quality of the battery cell. In addition, the laser equipment and the dust removal system occupy a large amount of limited production space, and the investment required for the complex dust removal system is also very large. Therefore, it is very important to provide a new method for connecting the battery cell tab and the top cover. SUMMARY

[0003] Therefore, the present application aims to provide a method for connecting a battery cell tab and a cover plate to solve the various problems caused by the laser welding process.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] A method for connecting a battery cell tab and a cover plate, the connection method comprising the following steps:

[0006] Step a: processing a tab riveting hole on the tab protruding from the assembled battery cell after entering the shell, and processing a cover plate riveting hole on the cover plate corresponding to the position of the tab riveting hole;

[0007] Step b: pre-aligning the tab riveting hole and the cover plate riveting hole, and maintaining the relative position of the assembled battery cell and the cover plate to form a component to be processed;

[0008] Step c: placing the component to be processed in step b on a riveting device, and aligning the riveting head with the tab riveting hole and the cover plate riveting hole;

[0009] Step d: installing a riveting piece on the riveting head, wherein the riveting piece is installed on the riveting head in a thin-walled tubular shape with an opening at one end, the riveting head drives the riveting piece to press down, so that the end of the riveting piece contacts the bottom of the cover plate riveting hole, and then the riveting head continues to press down, the thin wall of the opening of the riveting piece is expanded radially outward to gradually form an end limiting flange;

[0010] Step e: After the riveting head is in place, the end limiting flange is pressed tightly onto the electrode lug. Then the riveting head returns to its original position, completing the connection between the electrode lug and the cover plate.

[0011] Furthermore, in step d, the riveting head is provided with a negative pressure adsorption part, and the riveting component is installed on the riveting head through the negative pressure adsorption part.

[0012] Furthermore, the riveting component is interference-fitted with the riveting hole of the cover plate.

[0013] Furthermore, the riveting head is provided with a guide portion that expands the thin wall of the round tube outward.

[0014] Furthermore, the guide portion includes a flanged forming end face disposed on the riveting head.

[0015] Furthermore, the tabs include a positive tab and a negative tab extending from one end of the battery cell to be assembled, and the cover plate includes a cover plate body corresponding to the positive tab and the negative tab; and / or, the material of the rivet pressed between the positive tab and the cover plate body is the same as the material of the positive tab, and the material of the rivet pressed between the negative tab and the cover plate body is the same as the material of the negative tab.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The method for connecting the battery cell tabs and the cover plate described in this invention uses a press-fitting process to connect the battery cell tabs and the cover plate, which is beneficial for improving production cycle and increasing production efficiency. Moreover, the press-fitting process can effectively avoid spatter, dust and welding fumes generated in the laser welding process, eliminating the need for a complex dust removal mechanism, which is more conducive to ensuring battery cell quality. It can also reduce the equipment footprint and reduce equipment investment, thus achieving excellent results.

[0018] Furthermore, during the riveting process, the end of the riveted part is first placed against the bottom of the riveting hole in the cover plate. Then, under the continued downward pressure of the riveting head, the opening of the riveted part gradually expands outward, forming an end-limiting flange. After the riveting head is in place, the end-limiting flange can be pressed tightly onto the tab, thereby achieving the connection between the tab and the cover plate. As the riveting head continues to press down, it can further facilitate the interference fit between the riveted part and the riveting hole in the cover plate, thereby further improving the connection effect between the riveted part and the cover plate.

[0019] In addition, the negative pressure adsorption part on the riveting head facilitates the installation and removal of the riveting component from the riveting head. The guide part on the riveting head facilitates the forming of the end limiting flange, thereby improving the connection effect between the riveting component and the electrode tab. Using the same material as the positive electrode tab or the same material as the negative electrode tab for the riveting component helps to ensure the performance of the positive and negative electrodes, and also helps to ensure the performance of the battery cell.

[0020] Another object of the present invention is to provide a battery in which the cell tabs and the cover plate are connected by the above-described method for connecting cell tabs and the cover plate.

[0021] The battery of the present invention, by adopting the above-described method of connecting the cell tabs and the cover plate, is conducive to improving the production efficiency of the battery and also helps to ensure the quality of the battery.

[0022] Another object of the present invention is to provide a connection structure between a battery cell tab and a cover plate, the connection structure including a riveting member, a tab riveting hole provided on the tab and a cover plate riveting hole provided on the cover plate, the riveting member being press-fitted in the tab riveting hole and the cover plate riveting hole, and the riveting member having an end limiting flange for pressing the tab onto the cover plate.

[0023] Furthermore, the rivet is columnar, with one end of the rivet being hollow and forming a thin-walled tubular shape.

[0024] Furthermore, the electrode lug riveting holes are a plurality of holes spaced apart on the electrode lug, and the cover plate riveting holes are a plurality of holes corresponding to the electrode lug riveting holes; and / or, the cover plate is provided with a mounting groove corresponding to the end limiting flange, the mounting groove is connected to the cover plate riveting holes, and the diameter of the mounting groove is larger than the diameter of the cover plate riveting holes.

[0025] The connection structure between the battery cell tab and the cover plate of the present invention is simple in structure, can ensure a good connection effect between the tab and the cover plate, and can also avoid the occurrence of various problems caused by laser welding process in the prior art. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0027] Figure 1 This is a step diagram illustrating the connection method between the battery cell tab and the cover plate according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the positive electrode cover plate according to an embodiment of the present invention;

[0029] Figure 3 This is a partial cross-sectional view of the positive electrode cover plate according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the negative electrode cover plate according to an embodiment of the present invention;

[0031] Figure 5This is a partial cross-sectional view of the negative electrode cover plate according to an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the initial state of the riveted component according to an embodiment of the present invention;

[0033] Figure 7 This is a structural schematic diagram of the riveted component in the press-fit state according to an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the structure of the battery cell tabs and the cover plate being riveted together in an embodiment of the present invention;

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Positive electrode cover plate; 2. Negative electrode cover plate; 3. Riveting components; 101. Cover plate riveting hole; 102. Mounting groove; 30. Mounting hole; 301. End limiting flange;

[0037] 10. Battery cells to be assembled; 100. Electrode tabs. Detailed Implementation

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0039] In the description of this invention, it should be noted that the use of terms such as "upper," "lower," "inner," and "outer," indicating orientation or positional relationship, is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing the invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the use of terms such as "first" and "second" is also for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances.

[0041] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] This embodiment relates to a method for connecting the battery cell tab and the cover plate, which proposes a new connection method and can solve the problems of spatter, dust and welding fumes generated in the laser welding process, and can also reduce the equipment investment for configuring complex dust removal mechanisms.

[0043] In terms of overall design, see Figure 1 As shown, the connection method between the battery cell tab and the cover plate in this embodiment mainly includes the following steps:

[0044] Step a: Machining tab rivet holes on the tabs 100 extending from the battery cell 10 after it is installed in the casing, and machining cover plate rivet holes 101 on the cover plate at the positions corresponding to the tab rivet holes.

[0045] Step b: Align the tab riveting hole and the cover plate riveting hole 101 in advance, and maintain the relative position of the battery cell 10 to be assembled and the cover plate to form the part to be processed;

[0046] Step c: Place the part to be processed in step b on the riveting equipment and align the riveting head with the riveting hole of the electrode lug and the riveting hole 101 of the cover plate;

[0047] Step d: Install the riveting part 3 on the rivet head. The riveting part 3 is installed with a hole at one end of the rivet head and is in the shape of a thin-walled tube. The rivet head drives the riveting part 3 to press down, so that the end of the riveting part 3 contacts the bottom of the rivet hole 101 of the cover plate. Then the rivet head continues to press down, expanding the thin wall at the opening of the riveting part 3 radially outward to gradually form the end limiting flange 301.

[0048] Step e: After the riveting head is in place, the end limiting flange 301 is pressed tightly onto the tab 100. Then the riveting head returns to its original position, completing the connection between the tab 100 and the cover plate.

[0049] The lug riveting hole is a through hole, and its diameter is the same as or approximately the same as the diameter of the cover plate riveting hole 101, which facilitates the riveting of the riveting component 3 and improves the riveting effect of the riveting component 3. In addition, the riveting component 3 is preferably a cylindrical structure, and one end of the riveting component 3 is opened to form a thin-walled cylindrical tube. The opening is used for mounting on the riveting head.

[0050] In this embodiment, the use of a press-fitting process to connect the electrode tabs of the battery cell to the cover plate is beneficial to improving the production cycle and increasing production efficiency. Moreover, the press-fitting process can effectively avoid the spatter, dust and welding fumes generated in the laser welding process, eliminating the need for a complex dust removal mechanism, which is more conducive to ensuring the quality of the battery cell, and can also reduce the equipment footprint and reduce equipment investment.

[0051] In a specific design, in this embodiment, in step d above, to facilitate the fixing of the riveting component 3 to the riveting head, a negative pressure adsorption part is provided on the riveting head, and the riveting component 3 is installed on the riveting head through the negative pressure adsorption part. The negative pressure adsorption part can be, for example, a negative pressure suction hole, and to improve the adsorption effect, multiple negative pressure suction holes can be provided on the riveting head.

[0052] Furthermore, in specific implementation, a negative pressure channel connected to the negative pressure suction hole can be set inside the riveting head, for example. This negative pressure channel can be connected to a negative pressure device. In this way, under the negative pressure of the negative pressure device, the suction force at the negative pressure suction hole can firmly adsorb the riveting part 3 onto the riveting head, and it is also conducive to the detachment of the riveting part 3 from the riveting head, thereby facilitating the smooth riveting process of the riveting part 3.

[0053] In this embodiment, the riveting component 3 is interference-fitted with the riveting hole 101 of the cover plate. This improves the connection between the riveting component 3 and the cover plate and effectively prevents the riveting component 3 from falling off. Moreover, it should be noted that during the riveting process, when the riveting component 3 contacts the bottom of the riveting hole 101 of the cover plate, the continued pressing of the riveting head causes the riveting component 3 to expand, which further increases the interference between the riveting component 3 and the riveting hole 101 of the cover plate, thereby further improving the connection between the riveting component 3 and the cover plate.

[0054] In a preferred embodiment, the riveting head is provided with a guide portion that expands the thin wall of the tube outward to facilitate the formation of the end-limiting flange 301. Specifically, the guide portion includes a flange forming end face provided on the riveting head for forming the end-limiting flange 301, thus ensuring the forming quality of the end-limiting flange 301.

[0055] In this embodiment, the tab 100 extending from one end of the battery cell 10 to be assembled includes a positive tab and a negative tab. The cover plate includes a positive cover plate 1 and a negative cover plate 2 respectively provided for the positive and negative tabs. The riveting piece 3 riveted to the positive tab and the positive cover plate 1 is made of the same material as the positive tab. Similarly, the riveting piece 3 riveted to the negative tab and the negative cover plate 2 is made of the same material as the negative tab. This arrangement helps to ensure the performance of the positive and negative electrodes and, consequently, the performance of the battery cell.

[0056] The connection method between the battery cell tab and the cover plate in this embodiment uses a press-fitting process to connect the battery cell tab and the cover plate. This not only effectively avoids spatter, dust and welding fumes generated in the laser welding process, eliminating the need for complex dust removal mechanisms and ensuring battery cell quality, but also helps to increase production cycle time, improve production efficiency, and reduce equipment footprint and investment, thus achieving excellent results.

[0057] In addition, this embodiment also relates to a battery in which the cell tabs and the cover plate are connected using the connection method described above. It should be noted that the cell, casing, and other structures in the battery structure can refer to existing technologies.

[0058] In this embodiment, the battery uses the connection method described above to connect the cell tabs and the cover plate together by pressing and riveting, which helps to improve the battery production efficiency and also helps to ensure the quality of the battery.

[0059] Furthermore, this embodiment also relates to a connection structure between the battery cell tab and the cover plate, which is based on the connection method described above. See also Figures 2 to 8 As shown, the connection structure specifically includes a riveting member 3, a pole lug rivet hole on the pole lug 100 and a cover plate rivet hole 101 on the cover plate. The riveting member 3 is pressed into the pole lug rivet hole and the cover plate rivet hole 101, and the riveting member 3 has an end limiting flange 301 that presses the pole lug 100 onto the cover plate.

[0060] At this point, as mentioned above, the tab 100 includes a positive tab and a negative tab, both of which are provided with tab riveting holes. The cover plate includes a cover plate body corresponding to the positive and negative tabs. The cover plate body can be an integral structure, having two connecting ends respectively connected to the positive and negative tabs, with cover plate riveting holes 101 formed at both connecting ends. The tab riveting holes on the positive and negative tabs correspond to the two cover plate riveting holes 101.

[0061] It is understandable that the cover body can also be two separate covers, one for the positive electrode and one for the negative electrode, that is... Figures 2 to 5 As shown, the main body of the cover plate includes a positive cover plate 1 and a negative cover plate 2, which correspond to the positive and negative electrodes, respectively. Corresponding to the electrode tab riveting holes, cover plate riveting holes 101 are provided on the positive cover plate 1 and the negative cover plate 2, and each electrode tab riveting hole and cover plate riveting hole 101 are aligned.

[0062] The riveting component 3 in this embodiment is structurally as follows: Figure 6 and Figure 7 As shown, where Figure 6 This is a schematic diagram of the structure before riveting. Figure 7 This is a schematic diagram of the structure after press-fitting. Structurally, the riveting component 3 is columnar, and one end of the riveting component 3 is hollow, forming a thin-walled tubular shape. That is... Figure 6 and Figure 7 The mounting hole 30 shown is used to cooperate with the riveting head, so that the riveting part 3 is riveted into the tab riveting hole and the cover plate riveting hole 101 under the riveting action of the riveting head.

[0063] In a preferred embodiment of this invention, the tab rivet holes are arranged in a plurality of spaced-apart configurations on the tab 100, and the cover plate rivet holes 101 are arranged in a plurality of configurations corresponding to the tab rivet holes. This further improves the connection effect between the tab 100 and the cover plate.

[0064] To improve the riveting effect of the riveted part 3 after pressing, in this embodiment, a mounting groove 102 corresponding to the end limiting flange 301 is also provided on the cover plate. The mounting groove 102 communicates with the riveting hole 101 of the cover plate and is coaxially arranged, and the diameter of the mounting groove 102 is larger than the diameter of the riveting hole 101 of the cover plate. Preferably, see Figures 2 to 5 Both the positive electrode cover plate 1 and the negative electrode cover plate 2 are provided with mounting grooves 102, and the diameter of the mounting grooves 102 is larger than the diameter of the riveting holes 101 of the cover plates. In specific implementation, the diameter of the mounting grooves 102 can be adapted to the diameter of the end limiting flange 301 to prevent the diameter of the mounting grooves 102 from being too small to properly accommodate the end limiting flange 301, and also not too large to affect the structural strength of the cover plates.

[0065] Because the tab 100 has a certain degree of flexibility, when the tab 100 is riveted to the cover plate by the riveting member 3, the end limiting flange 301 of the end of the riveting member 3 is located in the mounting groove 102, so that after riveting, the end face of the cover plate is relatively flat, which is conducive to improving the subsequent installation effect of the cover plate and the battery cell housing.

[0066] The connection structure between the battery cell tab and the cover plate in this embodiment is relatively simple, easy to process and manufacture, and can ensure a good connection effect between the tab 100 and the cover plate. At the same time, it can avoid the various problems caused by the laser welding process in the prior art, and has good practicality.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1.A method for connecting a cell tab and a cover plate, characterized in that: the method comprises the following steps: step a, processing a tab riveting hole on the tab of a cell to be assembled after the cell is put into a shell, and processing a cover plate riveting hole on the cover plate at a position corresponding to the tab riveting hole; step b, pre-aligning the tab riveting hole and the cover plate riveting hole, and keeping the relative position of the cell to be assembled and the cover plate to form a part to be processed; step c, placing the part to be processed in step b on a riveting device, and aligning a riveting head with the tab riveting hole and the cover plate riveting hole; step d, installing a riveting piece on the riveting head, wherein the riveting piece is in the form of a thin-walled tube with an opening at one end of the riveting head, the riveting head drives the riveting piece to press down, so that the end of the riveting piece contacts the bottom of the cover plate riveting hole, and then the riveting head continues to press down, so that the thin wall of the opening of the riveting piece expands radially outward to gradually form an end limiting flange; step e, after the riveting head is riveted in place, the end limiting flange is pressed against the tab, and then the riveting head is returned to complete the connection between the tab and the cover plate; in step d, a negative pressure adsorption part is arranged on the riveting head, and the riveting piece is installed on the riveting head through the negative pressure adsorption part; the riveting piece is in interference fit with the cover plate riveting hole; a guide part is arranged on the riveting head to expand the thin wall of the circular tube outward, and the guide part comprises a flange forming end face arranged on the riveting head. 2.The method for connecting a cell tab and a cover plate according to claim 1, characterized in that: the tab comprises a positive tab and a negative tab extending from one end of a cell to be assembled, and the cover plate comprises a cover plate body arranged corresponding to the positive tab and the negative tab; and / or the material of the riveting piece riveted between the positive tab and the cover plate body is the same as that of the positive tab, and the material of the riveting piece riveted between the negative tab and the cover plate body is the same as that of the negative tab. 3.A battery, characterized in that: the connection between the tab of the cell and the cover plate of the battery is achieved by the method for connecting a cell tab and a cover plate according to claim 1 or 2. 4.A connection structure for connecting a cell tab and a cover plate, characterized in that: the connection structure is formed based on the method for connecting a cell tab and a cover plate according to claim 1, and the connection structure comprises a riveting piece, a tab riveting hole arranged on the tab, and a cover plate riveting hole arranged on the cover plate, the riveting piece is riveted in the tab riveting hole and the cover plate riveting hole, and the riveting piece has an end limiting flange for pressing the tab against the cover plate. 5.The connection structure for connecting a cell tab and a cover plate according to claim 4, characterized in that: the riveting piece is in the form of a column, and the riveting piece is hollow inside at one end and in the form of a thin-walled tube. 6.The connection structure for connecting a cell tab and a cover plate according to claim 5, characterized in that: the tab riveting hole is a plurality of holes arranged at intervals on the tab, and the cover plate riveting hole is a plurality of holes arranged corresponding to the tab riveting hole. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ And / or, the cover plate is provided with a mounting groove corresponding to the end limiting flange, the mounting groove is communicated with the cover plate riveting hole, and the diameter of the mounting groove is greater than that of the cover plate riveting hole.

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