A method for irregular welding of lithium batteries and lithium batteries

Abstract

This invention relates to a method for irregularly shaped welding of lithium batteries and a lithium battery itself. The method involves fixing a connecting piece to a cover plate, both of which have through holes. A terminal post is fixedly inserted into the through hole. Ultrasonic welding is used to form flat tooth weld marks on the cell tabs and the connecting piece. Laser welding is then used to weld the connections at these flat tooth weld marks on the cell tabs and the connecting piece. This method effectively saves on the tooling for loading and positioning the connecting piece and protective sheet, reduces the cost of the pre-welding machine, saves on the structural tooling for the connecting piece and protective sheet, optimizes the lithium battery design process, and reduces the number of process steps.

Description

Technical Field

[0001] This invention relates to a method for irregular welding of lithium batteries and lithium batteries, belonging to the field of cell processing technology. Background Technology

[0002] The assembly process of lithium-ion batteries includes a series of equipment processes such as preheating, hot pressing, ultrasonic pre-welding, ultrasonic final welding, cover plate laser welding, core bonding, casing pre-welding, and casing full welding. As an indispensable part of the lithium-ion battery production process, the control of its process capability directly affects the performance of lithium-ion batteries. Currently, there are still many areas for improvement in this process. For example, in the existing lithium battery assembly line manufacturing process, the assembly line refers to a line assembled from multiple lithium battery devices that manufacture batteries from cells.

[0003] In the current lithium-ion battery assembly process, the terminals, connecting tabs, and cover plates are separate and independent components. Laser welding is required to first weld the terminals, increasing the use of lasers and the number of steps. Furthermore, excessive welding steps can easily lead to welding defects, affecting yield. Additionally, the existing process requires protective plates when welding the tabs and connecting tabs; these protective plates are intended to prevent ultrasonic welding from cracking the tabs, adding to the positioning fixtures. A key technical challenge faced by every assembly line is how to ultrasonically weld the connecting tabs and laser weld the cover plates, making the optimization of ultrasonic pre-welding and cover plate laser welding processes one of the main difficulties. Summary of the Invention

[0004] To address the aforementioned problems, one objective of this invention is to provide a non-standard welding method for lithium batteries, which can effectively save on the tooling for loading and positioning connecting pieces and protective pieces, effectively reduce the cost of pre-welding machines, save on the structural tooling for connecting pieces and protective pieces, optimize the lithium battery design process, and reduce the process flow. Another objective of this invention is to provide a lithium battery manufactured using the aforementioned non-standard welding method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for irregularly shaped welding of lithium batteries, comprising the following steps:

[0007] The connecting piece is fixed to the cover plate. The cover plate and the connecting piece are provided with through holes, and the pole is fixedly inserted into the through holes.

[0008] Ultrasonic waves are used to form flat toothed solder marks on the battery cell tabs and the connecting piece, respectively.

[0009] The electrodes and connecting pieces are welded together using laser welding at the flat weld marks on the electrodes and connecting pieces.

[0010] Further, the connecting piece includes a positive connecting piece and a negative connecting piece, the pole includes a positive pole and a negative pole, the positive connecting piece and the negative connecting piece are fixedly connected with two ends of the cover plate respectively, the positive connecting piece is provided with a first through hole penetrating through one end of the cover plate, the positive pole is fixedly inserted into the first through hole, the negative connecting piece is provided with a second through hole penetrating through the other end of the cover plate, and the negative pole is fixedly inserted into the second through hole.

[0011] Further, the positive connecting piece and the negative connecting piece each include a horizontal connecting piece and a vertical connecting piece connected with at least one side of the horizontal connecting piece perpendicularly, the horizontal connecting piece is fixedly connected with the cover plate, and the flat-tooth welding mark is formed on the vertical connecting piece and used for welding connection with the electrode lug of the battery cell.

[0012] Further, the vertical connecting piece includes two, and the two vertical connecting pieces are symmetrically connected on two sides of the horizontal connecting piece, and the horizontal connecting pieces on two sides are respectively welded with an electrode lug of a battery cell.

[0013] Further, the positive connecting piece and / or the negative connecting piece are integrally formed, and the vertical connecting piece is formed by upward bending of one side or both sides of the positive connecting piece or the negative connecting piece.

[0014] Further, the method further includes the following steps:

[0015] After the flat-tooth welding mark on the electrode lug and the connecting piece is welded by laser welding, the vertical connecting piece is pressed flat to 180°.

[0016] Further, the method further includes the following steps: after the vertical connecting piece is pressed flat to 180°, the battery cell is formed by pasting glue.

[0017] Further, the connecting piece and the cover plate are fixed in a material, and specifically:

[0018] The flat-tooth welding is performed by using an inclined rod welding;

[0019] The flat-tooth welding area is welded by laser welding.

[0020] Another aspect of the present application also provides a lithium battery prepared by using the special-shaped welding method.

[0021] The present application has the following advantages due to the above technical scheme:

[0022] The connecting piece and the cover plate are connected in a material, so that the connecting piece feeding station is saved;

[0023] Ultrasonic wave forms flat-tooth welding mark on the surface of the tab and the connecting piece, and laser welding is used to ensure the welding overcurrent performance of the tab and the connecting piece;

[0024] The ultrasonic flat-tooth welding saves the traditional connecting piece and the protective piece loading station;

[0025] The laser is used to laser weld the connecting piece and the tab on the cover plate, avoiding the phenomenon of false welding and insufficient pulling force;

[0026] Overall, the connecting piece, the protective piece and the tab welding problem is solved, the machine table procurement cost is saved, the process flow is optimized, and the assembly line overall qualification rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the application. Throughout the drawings, same reference numerals are used for same components. In the drawings:

[0028] Figure 1 is a structure schematic diagram of the cover plate incoming material;

[0029] Figure 2 is a structure schematic diagram of the cover plate incoming material

[0030] Figure 3 is a front view of the cover plate incoming material;

[0031] Figure 4 is a structure schematic diagram of the cover plate incoming material without containing laser welding mark after the vertical connecting piece is pressed flat;

[0032] Figure 5 is a structure schematic diagram of the cover plate incoming material containing laser welding mark after the vertical connecting piece is pressed flat;

[0033] The various signs in the drawings represent the following:

[0034] 1-cover plate, 2-positive connecting piece, 3-negative connecting piece, 4-negative pole, 5-positive pole, 21-horizontal connecting piece, 22-vertical connecting piece. DETAILED DESCRIPTION

[0035] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood and so that the scope of the present application can be completely conveyed to those skilled in the art.

[0036] This invention provides a method for irregularly shaped welding of lithium batteries, comprising the steps of: fixing a connecting piece to a cover plate, wherein the cover plate and the connecting piece are provided with through holes, and an electrode post is fixedly inserted into the through holes; forming flat tooth weld marks on the cell tabs and the connecting piece respectively using ultrasonic waves; and welding the connection by laser welding the flat tooth weld marks on the cell tabs and the connecting piece. This method can effectively save on the tooling for loading and positioning the connecting piece and the protective piece, effectively save on the cost of the pre-welding machine, save on the structural tooling for the connecting piece and the protective piece, optimize the lithium battery design process, and reduce the process flow.

[0037] Combination Figures 1 to 5 As shown, an embodiment of the present invention provides a method for irregular welding of lithium batteries, including the following steps:

[0038] S1. The connecting piece 2 and the cover plate 1 are fixed together. The cover plate 1 and the connecting piece 2 are provided with through holes. The pole post 5 is fixedly inserted into the through hole.

[0039] S2. Using ultrasonic waves, flat toothed solder marks are formed on the battery cell tab (not shown in the figure) and the connecting piece 2 respectively;

[0040] S3. Welding connection is performed using laser welding on the electrode tabs and connecting piece 2 using the flat weld marks applied to the connecting piece 2.

[0041] like Figure 2 As shown, the connecting piece 2 includes a positive electrode connecting piece 2 and a negative electrode connecting piece 3, and the electrode post includes a positive electrode post 5 and a negative electrode post 4. The positive electrode connecting piece 2 and the negative electrode connecting piece 3 are respectively fixedly connected to both ends of the cover plate 1. The positive electrode connecting piece 2 and one end of the cover plate 1 are provided with a first through hole, and the positive electrode post 5 is fixedly inserted into the first through hole. The negative electrode connecting piece 3 and the other end of the cover plate 1 are provided with a second through hole, and the negative electrode post 4 is fixedly inserted into the second through hole.

[0042] For ease of welding, both the positive electrode connecting piece 2 and the negative electrode connecting piece 3 include a horizontal connecting piece 21 and vertical connecting pieces 22 perpendicularly connected to both sides of the horizontal connecting piece 21. The horizontal connecting piece 21 is fixedly connected to the cover plate 1, and the vertical connecting pieces 22 on both sides are welded to the electrode tabs. Both the positive electrode connecting piece 2 and the negative electrode connecting piece 3 are integral sheet structures. The vertical connecting piece 22 is formed by bending the positive electrode connecting piece 2 or the negative electrode connecting piece 3. The bent portion is the vertical connecting piece 22, and the horizontal portion perpendicular to the bent portion is the horizontal connecting piece 21.

[0043] Furthermore, the method further includes the following steps:

[0044] S4, such as Figure 4 and Figure 5As shown, the vertical connecting piece 22 is pressed to 180° after the laser welding of the flat ruler welding mark, as shown in Figure 3

[0045] S5, after the vertical connecting piece is pressed to 180°, the rubber is pasted and the core is formed into a double-core.

[0046] As an embodiment, the vertical connecting piece 22 on both sides can be welded with an electrode lug respectively, and finally bent to form a double-core structure.

[0047] As another embodiment, the positive connecting piece 2 and the negative connecting piece 3 can also be arranged to be bent on one side to form a vertical connecting piece 22, which is welded with the electrode lug and pressed to 180° to form a single-core lithium battery.

[0048] The fixed connection of the cover plate 1 and the positive connecting piece 2 or the negative connecting piece 3 includes the following steps:

[0049] The flat tooth welding is performed by using inclined rod welding;

[0050] The flat tooth welding area is welded by using laser welding.

[0051] The whole preparation process in the application is realized by using cover plate as raw material, fixing the cover plate 1 and the positive connecting piece 2 and / or the negative connecting piece 3 containing the vertical connecting piece 22 together, performing flat tooth welding of the electrode lug by using inclined rod gap welding, performing strip welding by using laser welding, pressing the vertical connecting piece 22 to 180° connecting piece by using a bending mechanism, and forming a bundled double-core by using the rubber pasting core function.

[0052] The method can effectively save the connecting piece and the protection piece loading positioning tool, effectively save the pre-welding machine cost, save the connecting piece and the protection piece structure tool, optimize the lithium battery design process, reduce the process flow, solve the complicated problem of connecting piece, protection piece and electrode lug welding, save the machine procurement cost and process flow optimization, and improve the whole line qualification rate of the assembly line.

[0053] Another embodiment of the application provides a lithium battery prepared by using the special-shaped welding method of the lithium battery.

[0054] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.​

Claims

1. A method for irregularly shaped welding of lithium batteries, characterized in that, Including the following steps: The connecting piece is fixed to the cover plate. The cover plate and the connecting piece are provided with through holes, and the pole is fixedly inserted into the through holes. Ultrasonic waves are used to form flat toothed solder marks on the battery cell tabs and the connecting piece, respectively. Laser welding is used to weld the tabs and connecting pieces to the flat tooth weld marks on the tabs and connecting pieces. Each connecting piece includes a horizontal connecting piece and a vertical connecting piece that is perpendicularly connected to at least one side of the horizontal connecting piece. The horizontal connecting piece is fixedly connected to the cover plate. The vertical connecting piece has a flat toothed welding mark formed on it. The flat toothed welding mark is used for welding connection with the battery cell tab. It also includes the following steps: After welding the tabs and connecting pieces using laser welding with the flat welding marks on the laser welder, the vertical connecting piece is flattened to 180°. After the vertical connecting piece is flattened to 180°, adhesive is applied and the cores are joined to form a dual-cell lithium battery.

2. The irregular welding method for lithium batteries according to claim 1, characterized in that, The connecting piece includes a positive connecting piece and a negative connecting piece, and the electrode includes a positive electrode and a negative electrode. The positive connecting piece and the negative connecting piece are respectively fixedly connected to both ends of the cover plate. The positive connecting piece and one end of the cover plate are provided with a through hole, and the positive electrode is fixedly inserted into the first through hole. The negative connecting piece and the other end of the cover plate are provided with a through hole, and the negative electrode is fixedly inserted into the second through hole.

3. The irregular welding method for lithium batteries according to claim 1, characterized in that, The vertical connecting piece includes two pieces, which are symmetrically connected to both sides of the horizontal connecting piece. The horizontal connecting pieces on both sides are respectively welded to a battery cell tab.

4. The irregular welding method for lithium batteries according to claim 2, characterized in that, The positive electrode connecting piece and / or the negative electrode connecting piece are integrally formed, and the vertical connecting piece is formed by bending one or both sides of the positive electrode connecting piece or the negative electrode connecting piece upward.

5. The irregular welding method for lithium batteries according to claim 1, characterized in that, The connecting piece is fixed to the cover plate upon arrival, specifically as follows: Flat tooth welding is performed using diagonal bar welding. Then, laser welding is used to weld the flat toothed area.

6. A lithium battery, characterized in that, It is prepared by the non-shaped welding method as described in any one of claims 1 to 5.

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