A square lithium-ion battery with staggered tabs and a tab welding device

Abstract

The present invention discloses a square lithium-ion battery with staggered tabs and a tab welding device, aiming to solve the bottleneck problem of the number of tab layers in ultrasonic welding of existing ultra-thick pole groups. The invention includes a pole group composed of pole pieces using a lamination process, with tabs provided on the pole pieces, and the pole pieces and tabs are staggered and stacked, and a connecting piece is provided at one end of the staggered and stacked pole pieces and tabs. The present invention uses the pole piece lamination process to stack the positive and negative pole pieces, and the pole pieces and tabs are staggered with each other, and then are welded on the connecting piece by ultrasonic welding, so that the original ultra-thick pole group is divided into two, and the number of tab welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding; thereby effectively avoiding the risk of short circuit of the battery cell output line caused by welding slag due to ultra-thick pole groups (with more than 60 tabs) during laser welding, and causing serious damage to the battery cell tabs.

Description

Technical Field

[0001] The present invention relates to the technical field related to new energy, and more specifically, to a square lithium-ion battery with staggered tabs and a tab welding device. Background Art

[0002] With the development of the lithium battery industry, lithium-ion batteries are moving towards higher capacity and higher volume energy density. However, the number of layers of ultrasonic welding of the tabs has become a bottleneck that hinders its development. At present, the tab welding usually adopts ultrasonic welding, and its welding capacity generally does not exceed 60 layers of tabs. If the number of layers exceeds this, there will be risk accidents such as tab cold welding and breakage. This welding method cannot achieve the welding of thick tabs with more than 60 layers of tabs. With the demand for energy storage and power, the demand for large-capacity ultra-thick batteries is imperative.

[0003] Similar to the present invention, laser welding is also used in the industry for welding of ultra-thick electrode groups with more than 60 layers, but laser welding will produce welding slag, resulting in the risk of short circuit of the battery cell output line, and cause serious damage to the battery cell tabs. Therefore, this solution has certain disadvantages. Summary of the invention

[0004] The present invention overcomes the bottleneck problem of the number of layers of ultrasonically welded pole tabs in existing ultra-thick pole groups, and provides a square lithium-ion battery with staggered pole tabs and a pole tab welding device, which can divide the pole tabs of an originally ultra-thick pole group (with more than 60 pole tabs) into two, reducing the number of single welding layers, thereby effectively solving the bottleneck problem of the number of ultrasonic pole tab layers.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: a square lithium-ion battery with staggered tabs and a tab welding device, comprising: a pole group formed by a pole piece using a lamination process, a pole piece provided with a tab, a pole piece and a tab between the pole pieces and the tab are staggered, and a connecting piece is provided at one end of the staggered tab. The present invention uses the pole piece lamination process to stack the positive and negative pole pieces, and the pole pieces and tabs are staggered with each other, and then are welded on the connecting piece by ultrasonic welding, so that the original ultra-thick pole group is divided into two, and the number of tab welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding; thereby effectively avoiding the risk of short circuit of the battery cell output line caused by welding slag due to ultra-thick pole groups (tabs with more than 60 layers) during laser welding, and causing serious damage to the tabs of the battery cell.

[0006] Preferably, the pole piece adopts a lamination process to form a pole group consisting of two groups of battery cells, and the pole piece tabs in the two groups of battery cells are arranged alternately. The innovation of the two groups of battery cells is that the pole tabs of the two groups of battery cells are alternately welded on the connecting sheet by ultrasonic welding, so that the originally super thick pole group is divided into two, and the number of pole tab welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding.

[0007] Preferably, the electrode group is composed of a plurality of electrode group units stacked together, and the electrode group unit is composed of four electrode sheets stacked together, and the electrode sheets and pole ears in the electrode group unit are arranged crosswise. The above structure is welded to the connecting sheet by ultrasonic welding, so that the originally super thick electrode group is divided into two, and the number of electrode ear welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding.

[0008] Preferably, the pole ears include positive pole ears and negative pole ears, and all positive pole ears on the pole group unit are on one side, and all negative pole ears are on the other side. In this structure, the pole ears of each pole sheet are crossed with each other, and all pole sheets are stacked into a pole group by a lamination process. The characteristic of this pole group is that one pole group has four pole ears and all positive pole ears are on one side, and all negative pole ears are on one side. By welding on the connecting sheet by ultrasonic welding, the originally super thick pole group is divided into two, and the number of pole ear welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding.

[0009] A pole tab welding device includes a base, two columns arranged on the base, an ultrasonic welding device arranged between the two columns, two transversely movable driving blocks on the ultrasonic welding device, and a liftable welding head on the driving block; a welding box that can move forward and backward is arranged on the base, and a positioning groove for placing a battery cell and a welding positioning groove for welding the pole tab and a connecting piece are arranged on the welding box. The driving block in the device can be hydraulically or electrically controlled to make two welding heads move synchronously toward or away from each other. In the first step, the driving block is controlled to move to the top of the end pole piece, and then the two welding heads are driven to descend synchronously to perform ultrasonic welding on the superimposed pole piece and the pole tab, completing the end misaligned pole tab welding, and then the two welding heads are driven to rise and reset to the initial height; in the second step, the driving block is controlled to move to the top of the pole piece on the inner side of the pole pieces at both ends, and then the welding of the inner misaligned pole tab is realized through the above-mentioned first step welding process.

[0010] Preferably, an extrusion molding device is provided in the welding box, and the extrusion molding device includes a driving slide rod, a rotating pressure plate, and a flat pressing mechanism arranged in the welding positioning groove. A slide rod cavity is provided in the welding positioning groove, and a telescopic spring is provided between the slide rod cavity and the driving slide rod. A mechanical transmission mechanism is provided in the welding box to mechanically transmit the driving slide rod, the rotating pressure plate and the flat pressing mechanism. The driving slide rod can be pushed down by the welding head, and then the rotating pressure plate is driven to rotate 90° by the mechanical transmission mechanism, so that the connecting piece is bent along the intersection of the pole ear. At the same time, the mechanical transmission mechanism drives the flat pressing mechanism to start, so that the bent connecting piece is bent twice toward the side close to the pole ear; a hydraulic transmission mechanism is provided in the welding box to hydraulically transmit the driving slide rod and the flat pressing mechanism. When the welding head pushes the driving slide rod to descend to a certain position, the driving slide rod drives the hydraulic transmission mechanism to start, thereby pressing down the connecting piece after the secondary bending, so as to achieve complete covering of the connecting piece and the pole ear. When the second step of welding in the above process is carried out, the non-welding part at the front end of the welding head moves downward into the welding positioning groove and contacts with the driving slide rod. Continuing to descend can drive the driving slide rod to slide along the slide rod cavity, thereby driving the mechanical transmission mechanism to transmit, so that the rotating pressure plate rotates 90° along the rotating shaft, so that the connecting piece is bent along the intersection of the pole ear. At the same time, the mechanical transmission mechanism drives the flat pressing mechanism to start, so that the bent connecting piece is bent a second time toward the side close to the pole ear; when the two bends are completed, the mechanical transmission mechanism is disconnected from the driving slide rod. At this time, the driving slide rod drives the hydraulic transmission mechanism to start, so as to press down the connecting piece after the second bending, so as to achieve complete covering of the connecting piece and the pole ear.

[0011] Preferably, the mechanical transmission mechanism includes a transmission mechanism 1 and a transmission mechanism 2, the transmission mechanism 1 includes a rotating shaft 1 and a rotating shaft 2 rotatably arranged in the welding box, the rotating shaft 1 is provided with a gear 1 and a pulley 1, the gear 1 is meshed and connected with the rack on the driving slide rod, the rotating shaft of the rotating pressure plate is provided with a pulley 2, the rotating shaft 2 is provided with a pulley 3, a pulley 4 and a pulley 5, a belt 1 is provided between the pulley 1 and the pulley 3, and a belt 2 is provided between the pulley 4 and the pulley 2.

[0012] Preferably, the flat pressing mechanism includes a bending push rod slidably arranged in the welding positioning groove, a rack slide rod arranged on the bending push rod, and a lower pressure plate arranged in the bending push rod. The transmission mechanism 2 includes a pulley 5, a guide slider, and a rotating shaft 3 arranged on the rotating shaft 2. The rotating shaft 3 is provided with a gear 2 and a pulley 6. The gear 2 is connected to the rack slide rod, and a belt 3 is arranged between the pulley 5 and the pulley 6. In the present invention, a gear cavity is arranged in the right wall of the slide rod cavity, a pulley cavity is arranged at the rear side of the gear cavity, the rotating shaft 1 is rotatably arranged between the gear cavity and the pulley cavity, the rotating shaft 2 is rotatably arranged on the front and rear side walls of the pulley cavity behind the rotating shaft 1, a fixed pulley is arranged on the right side of the rotating shaft 2 in the pulley cavity, the rotating shaft 3 is located on the upper side of the fixed pulley, and the belt 3 connecting the pulley 5 and the pulley 6 passes through the fixed pulley. This structure facilitates power transmission.

[0013] Preferably, the hydraulic transmission mechanism includes a hydraulic pipe with hydraulic oil inside, a slide bar 1 and a slide bar 2 arranged at the ends of the hydraulic pipe, the other end of the slide bar 1 extends into the slide bar cavity, a spring is arranged between the slide bar cavity and the slide bar 1, and the slide bar 2 is connected to the lower pressure plate. This structure is used for pressing and fixing the connection after bending and coating.

[0014] As a preferred embodiment, a slide rail is provided on the base. The structure is used for positioning and fixing the welding box and belongs to the prior art.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention is provided with a plurality of superimposed electrode groups, which can divide the electrode tabs of an ultra-thick electrode group (with more than 60 electrode tabs) into two by stacking the lamination process, thereby reducing the number of single welding layers, thereby effectively solving the bottleneck problem of the number of ultrasonic electrode tab layers; (2) The present invention is provided with an electrode tab welding device, which can realize the electrode tab welding and the extrusion coating of the electrode tab in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of embodiment 1 of the present invention;

[0017] Figure 2 is a schematic structural diagram of Embodiment 2 of the present invention;

[0018] Figure 3 is a schematic structural diagram of Embodiment 3 of the present invention;

[0019] Figure 4 is a schematic structural diagram of embodiment 4 of the present invention;

[0020] Figure 5 yes Figure 4 A partial enlarged view of the area “A”;

[0021] Figure 6 yes Figure 5 Sectional view at "BB" in the middle;

[0022] Figure 7 yes Figure 6 Sectional view at "CC" in the figure;

[0023] Figure 8 is a cross-sectional view of a welding box in the present invention;

[0024] In the figure: pole piece 1, pole group 2, pole ear 3, positive pole piece 4, negative pole piece 5, connecting piece 6, base 101, column 102, ultrasonic welding device 103, driving block 104, welding head 105, welding box 106, positioning groove 107, welding positioning groove 108, slide rail 109, extrusion molding device 200, driving slide bar 201, rotating plate 202, flat pressing mechanism 203, slide bar cavity 204, telescopic spring 205, rotating shaft 301, rotating Shaft two 302, gear one 303, pulley one 304, pulley two 305, pulley three 306, pulley four 307, pulley five 308, belt one 309, belt two 310, guide slider 311, rotating shaft three 312, gear two 313, pulley six 314, belt three 315, bending push rod 401, rack slide bar 402, lower pressure plate 403, hydraulic pipe 501, slide bar one 502, slide bar two 503, spring 504, bump 505. DETAILED DESCRIPTION

[0025] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0026] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0027] A square lithium-ion battery with staggered tabs and a tab welding device (see attached Figure 1-5 ), including: a pole piece 1 is stacked to form a pole group 2, a pole piece 1 is provided with a pole ear 3, the pole piece 1 includes a positive pole piece 4 and a negative pole piece 5, the pole piece 1 and the pole ear 2 are staggered and stacked, and a connecting piece 6 is provided at one end of the staggered and stacked pole piece 1 and the pole ear 2. The present invention stacks the pole pieces by the pole piece stacking process, so that the positive and negative pole pieces are cross-stacked, and the pole pieces and the pole ears are staggered, and then welded to the connecting piece by ultrasonic welding, so that the original ultra-thick pole group is divided into two, and the number of pole ear welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding; thereby effectively avoiding the risk of short circuit of the battery cell output line caused by welding slag due to the ultra-thick pole group (more than 60 pole ears) during laser welding, and causing serious damage to the pole ears of the battery cell. Specific embodiment 1:

[0029] See attached Figure 1 This embodiment is further defined on the basis of the specific embodiment 1, wherein the pole piece adopts a lamination process to form a pole group consisting of two groups of battery cells, and the pole piece tabs in the two groups of battery cells are arranged alternately. The innovation of the two groups of battery cells is that the pole tabs of the two groups of battery cells are alternately welded on the connecting sheet by ultrasonic welding, so that the originally super thick pole group is divided into two, and the number of pole tab welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding. Specific embodiment 2:

[0031] See attached Figure 2 This embodiment is further defined on the basis of the specific embodiment 1, wherein the pole group is composed of a plurality of pole group units stacked together, the pole group unit is composed of four pole pieces stacked together, and the pole pieces and pole ears in the pole group unit are arranged crosswise with each other. The above structure is welded to the connecting sheet by ultrasonic welding, so that the originally super thick pole group is divided into two, and the number of pole ear welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding. Specific embodiment 3:

[0033] See attached Figure 3 This embodiment is further defined on the basis of the specific embodiment 2, and the pole ears include positive pole ears and negative pole ears, and all the positive pole ears on the pole group unit are on one side, and all the negative pole ears are on the other side. In this structure, the pole ears of each pole piece are crossed with each other, and all the pole pieces are stacked into a pole group by a lamination process. The characteristic of this pole group is that a pole group has four pole ears and all the positive pole ears are on one side, and all the negative pole ears are on one side. By welding on the connecting sheet by ultrasonic welding, the originally super thick pole group is divided into two, and the number of pole ear welding layers is reduced by half, which effectively avoids the bottleneck problem of ultrasonic welding. Specific embodiment 4:

[0035] See attached Figure 1 To Attachment Figure 8 This embodiment is a pole piece and pole tab welding device, which can be used for welding and connecting the pole group pole tabs of the first, second and third embodiments. A pole tab welding device includes a base 101, two columns 102 arranged on the base, an ultrasonic welding device 103 arranged between the two columns, two laterally movable driving blocks 104 are arranged on the ultrasonic welding device 103, and a lifting welding head 105 is arranged on the driving block 104 (the lifting structure is a prior art and is not described in detail in this application); a welding box 106 that can move forward and backward is arranged on the base 101, and a positioning groove 107 for placing the battery cell and a welding positioning groove 108 for welding the pole tab 2 and the connecting piece 6 are arranged on the welding box 106. The driving block in the device can be controlled hydraulically or electrically to make the two welding heads move toward or away from each other synchronously. In the first step, the driving block is controlled to move to just above the end pole piece, and then the two welding heads are driven to descend synchronously to perform ultrasonic welding on the superimposed pole piece and pole ear, completing the end misaligned pole ear welding, and then the two welding heads are driven to rise and reset to the initial height; in the second step, the driving block is controlled to move to just above the pole piece on the inner side of the pole pieces at both ends, and then the welding of the inner misaligned pole ear is achieved through the above-mentioned first step welding process.

[0036] The welding box 106 is provided with an extrusion molding device 200, which includes a driving slide bar 201, a rotating pressure plate 202, and a flat pressing mechanism 203 arranged in the welding positioning groove 108. The welding positioning groove 108 is provided with a slide bar cavity 204, and a telescopic spring 205 is provided between the slide bar cavity 204 and the driving slide bar 201. The welding box 106 is provided with a mechanical transmission mechanism that enables the driving slide bar 201 to mechanically transmit the rotating pressure plate 202 and the flat pressing mechanism 203. The driving slide bar 201 can be pushed down by the welding head 105, and then the mechanical transmission mechanism is used to transmit the mechanical transmission of the driving slide bar 201 to the rotating pressure plate 202 and the flat pressing mechanism 203. The driving mechanism drives the rotating pressure plate 202 to rotate 90°, so that the connecting piece 6 is bent along the intersection of the pole ear. At the same time, the mechanical transmission mechanism drives the flat pressing mechanism 203 to start, so that the bent connecting piece is bent again toward the side close to the pole ear. A hydraulic transmission mechanism is provided in the welding box 106 to hydraulically transmit the driving slide rod 201 and the flat pressing mechanism 203. When the welding head 105 pushes the driving slide rod 201 down to a certain position, the driving slide rod 201 drives the hydraulic transmission mechanism to start, thereby pressing down the connecting piece after the secondary bending, so as to achieve complete covering of the connecting piece 6 and the pole ear. When the second step of welding in the above process is carried out, the non-welding part at the front end of the welding head moves downward into the welding positioning groove and contacts with the driving slide bar. Continuing to descend can drive the driving slide bar 201 to slide along the slide bar cavity 204, thereby driving the mechanical transmission mechanism to transmit, so that the rotating pressure plate rotates 90° along the rotating shaft, so that the connecting piece 6 is bent along the intersection of the pole ear. At the same time, the mechanical transmission mechanism drives the flat pressing mechanism to start, so that the bent connecting piece is bent a second time toward the side close to the pole ear; when the two bends are completed, the mechanical transmission mechanism is disconnected from the driving slide bar. At this time, the driving slide bar drives the hydraulic transmission mechanism to start, so as to press down the connecting piece after the second bending, so as to achieve complete covering of the connecting piece and the pole ear.

[0037] The mechanical transmission mechanism includes a transmission mechanism 1 and a transmission mechanism 2. The transmission mechanism 1 includes a rotating shaft 1 301 and a rotating shaft 2 302 rotatably arranged in the welding box. The rotating shaft 1 301 is provided with a gear 1 303 and a pulley 1 304. The gear 1 303 is meshed with the rack on the driving slide bar 201. The rotating shaft of the rotating pressure plate 202 is provided with a pulley 2 305. The rotating shaft 2 302 is provided with a pulley 3 306, a pulley 4 307 and a pulley 5 308. A belt 1 309 is provided between the pulley 1 304 and the pulley 3 306, and a belt 2 310 is provided between the pulley 4 307 and the pulley 2 305.

[0038] The flat pressing mechanism 203 includes a bending push rod 401 slidably arranged in the welding positioning groove 108, a rack slide bar 402 arranged on the bending push rod 401, and a lower pressure plate 403 arranged in the bending push rod 402. The transmission mechanism 2 includes a pulley 5 308, a guide slider 311, and a rotating shaft 312 arranged on the rotating shaft 2 302. The rotating shaft 312 is provided with a gear 2 313 and a pulley 6 314. The gear 2 313 is connected to the rack slide bar 402, and a belt 315 is provided between the pulley 5 308 and the pulley 6 314. According to the present invention, a gear cavity is provided in the right wall of the slide rod cavity, a pulley cavity is provided on the rear side of the gear cavity, a rotating shaft 1 is rotatably provided between the gear cavity and the pulley cavity, a rotating shaft 2 is rotatably provided on the front and rear side walls of the pulley cavity behind the rotating shaft 1, a fixed pulley is provided on the right side of the rotating shaft 2 in the pulley cavity, a rotating shaft 3 is located on the upper side of the fixed pulley, a belt 3 connecting the pulley 5 and the pulley 6 passes through the fixed pulley, and this structure facilitates power transmission.

[0039] The hydraulic transmission mechanism includes a hydraulic pipe 501 with hydraulic oil inside, a slide bar 1 502 and a slide bar 2 503 arranged at the end of the hydraulic pipe 501, the other end of the slide bar 1 extends into the slide bar cavity, a spring 504 is arranged between the slide bar cavity and the slide bar 1, a convex block 505 is arranged on the slide bar 1, the spring 504 is arranged between the lower side wall of the convex block and the bottom wall of the slide bar cavity, and the slide bar 2 is connected to the lower pressure plate. This structure is used for pressing and fixing the connection after bending and coating.

[0040] Workflow: When it is necessary to weld the pole piece and the pole ear, first control the drive block to drive so that the two welding heads move toward or away from each other synchronously. In the first step, control the drive block to move to just above the end pole piece, and then drive the two welding heads to descend synchronously to perform ultrasonic welding on the superimposed pole piece and the pole ear to complete the welding of the end misaligned pole ear, and then drive the two welding heads to rise and reset to the initial height; in the second step, control the drive block to move to just above the pole piece on the inner side of the pole pieces at both ends, and then realize the welding of the inner misaligned pole ear through the above-mentioned first step welding process.

[0041] When the second step of welding in the above process is carried out, when the non-welding part at the front end of the welding head moves downward into the welding positioning groove, it will contact the driving slide bar. Continuing to descend can drive the driving slide bar to slide along the slide bar cavity, thereby driving gear one, shaft one, pulley one, pulley three, shaft two, pulley four, and pulley two to rotate in turn, thereby driving the rotating pressure plate to rotate 90° along the shaft, so that the connecting piece is bent along the intersection of the pole ear. At the same time, the rotation of shaft two drives pulley five, fixed pulley, pulley six, shaft three, and gear three to rotate in turn, thereby driving the rack slide bar to move horizontally toward the side close to the pole piece, thereby driving the bending push rod to perform a secondary bend on the connecting piece after bending on one side; when the two bends are completed, the driving slide bar is disconnected from gear one. At this time, the driving slide bar drives the hydraulic transmission mechanism to start, thereby pressing down the connecting piece after the secondary bending, so as to achieve complete covering of the connecting piece and the pole ear. Specific embodiment 5:

[0043] See attached Figure 4 This embodiment is based on the embodiment 6 and a slide rail 109 is added. The slide rail 109 is arranged on the base 101. This structure is used for positioning and fixing the welding box and belongs to the prior art.

[0044] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A tab welding device for a square lithium-ion battery with staggered tabs, characterized in that: It includes a base, two columns arranged on the base, an ultrasonic welding device arranged between the two columns, two transversely movable driving blocks are arranged on the ultrasonic welding device, and a lifting welding head is arranged on the driving block; a welding box that can move forward and backward is arranged on the base, and a positioning groove for placing the battery cell and a welding positioning groove for welding the pole ear and the connecting piece are arranged on the welding box; an extrusion molding device is arranged in the welding box, and the extrusion molding device includes a driving slide bar arranged in the welding positioning groove, a rotating pressure plate, and a flat pressing mechanism, a slide bar cavity is arranged in the welding positioning groove, and a telescopic spring is arranged between the slide bar cavity and the driving slide bar, a mechanical transmission mechanism for mechanically transmitting the driving slide bar, the rotating pressure plate and the flat pressing mechanism is arranged in the welding box, and a hydraulic transmission mechanism for hydraulically transmitting the driving slide bar and the flat pressing mechanism is arranged in the welding box; the driving slide bar can be pushed down by the welding head, and then the rotating pressure plate is driven to rotate 90° by the mechanical transmission mechanism, so that the connecting piece is bent along the intersection of the pole ear, and at the same time, the mechanical transmission mechanism drives the flat pressing mechanism to start, so that the bent connecting piece is bent twice to the side close to the pole ear; When the welding head pushes the driving slide rod down to a certain position, the driving slide rod drives the hydraulic transmission mechanism to start, thereby pressing down the connecting piece after the secondary bending, so as to achieve complete covering of the connecting piece and the pole ear.

2. The tab welding device according to claim 1, characterized in that: The mechanical transmission mechanism includes transmission mechanism 1 and transmission mechanism 2. Transmission mechanism 1 includes rotating shaft 1 and rotating shaft 2 rotatably arranged in the welding box. Rotating shaft 1 is provided with gear 1 and pulley 1. Gear 1 is meshed and connected with the rack on the driving slide rod. Pulley 2 is provided on the rotating shaft of the rotating pressure plate. Rotating shaft 2 is provided with pulley 3, pulley 4 and pulley 5. Belt 1 is provided between pulley 1 and pulley 3, and belt 2 is provided between pulley 4 and pulley 2.

3. The tab welding device according to claim 2, characterized in that: The flat pressing mechanism includes a bending push rod slidably arranged in the welding positioning groove, a rack slide rod arranged on the bending push rod, and a lower pressure plate arranged in the bending push rod. The transmission mechanism 2 includes a pulley 5, a guide slider, and a rotating shaft 3 arranged on the rotating shaft 2. The rotating shaft 3 is provided with a gear 2 and a pulley 6. The gear 2 is connected to the rack slide rod, and a belt 3 is provided between the pulley 5 and the pulley 6.

4. The tab welding device according to claim 2 or 3, characterized in that: The hydraulic transmission mechanism includes a hydraulic pipe with hydraulic oil inside, a slide bar 1 and a slide bar 2 arranged at the ends of the hydraulic pipe, the other end of the slide bar 1 extends into the slide bar cavity, a spring is arranged between the slide bar cavity and the slide bar 1, and the slide bar 2 is connected to the lower pressure plate.

5. The tab welding device according to claim 1, characterized in that: A slide rail is arranged on the base.

6. A square lithium-ion battery with staggered tabs suitable for the tab welding device of claim 1, characterized in that: include: The pole group is formed by the pole pieces using the lamination process, the pole pieces are provided with pole ears, the pole pieces and the pole ears are staggered and stacked, and a connecting piece is provided at one end of the staggered and stacked pole piece ears; the pole group is composed of a plurality of stacked pole group units, and the pole group unit is composed of four stacked pole pieces, and the pole pieces and the pole ears in the pole group unit are cross-arranged with each other.

7. A square lithium-ion battery with staggered tabs according to claim 6, characterized in that: The pole pieces are formed into a pole group consisting of two groups of battery cells by a lamination process, and the pole piece ears in the two groups of battery cells are arranged alternately.

8. The square lithium-ion battery with staggered tabs according to claim 6, characterized in that: The pole tabs include positive pole tabs and negative pole tabs. All positive pole tabs on the pole group unit are on one side, and all negative pole tabs are on the other side.

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