A tab welding device and method for a soft-pack battery, and the battery itself.

Abstract

This invention provides a tab welding device and method for soft-pack batteries, and a battery comprising a body, a welding head, a welding seat, and a positioning fixture. The welding seat is disposed on one side of the body, and the welding head is connected to the body and positioned above the welding seat. The welding seat includes a welding platform with a first groove and a second groove, which communicate with each other. The first groove is used to place the battery cell, and the second groove is used to place the first tab. The positioning fixture is disposed above the first groove and detachably connected to the welding platform. The positioning fixture and the second groove are used to fix the second tab. This invention uses the above-mentioned welding device to weld the first tab and the second tab, which not only has a fast welding speed and high yield, but also significantly improves battery breakage and electrode pulling, while reducing the internal resistance of the battery cell by 15%.

Description

Technical Field

[0001] This invention relates to the field of electrode welding technology, specifically to an electrode welding device and method for a pouch battery, and the battery itself. Background Technology

[0002] In pouch cells manufactured using stacked electrodes, the individual electrodes need to be welded together and attached to the outer tabs. A certain area must be reserved within the aluminum-plastic film at the welding points of the inner and outer tabs. This area is essentially an ineffective region that does not increase battery capacity. To reduce the volume of this ineffective region, folding welding technology is required. In recent years, lithium-ion battery technology using silicon as the primary negative electrode active material has become increasingly mature. However, due to the inherent properties of silicon, when using silicon as the negative electrode material, the macroscopic expansion of the negative electrode can exceed 50%, far higher than the 20% of graphite. In batteries using traditional folding welding methods, this significant expansion of the negative electrode causes the electrode to be stretched. Slight stretching can lead to wrinkles in the electrode, increasing internal resistance and causing lithium plating; severe stretching can result in electrode breakage. Therefore, overcoming these technical problems and defects is a key issue that needs to be addressed. Summary of the Invention

[0003] In response to the problems of high expansion rate of silicon-containing negative electrodes, severe tab stretching, leading to electrode wrinkling, which in turn increases the internal resistance of the battery and causes lithium plating, and if the expansion is large, the stretching will be more severe and may even lead to tab breakage, this invention provides a tab welding device and tab welding method for soft-pack batteries, as well as the battery itself.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0005] The first aspect of the present invention provides a tab welding device for a pouch battery, comprising a body, a welding head, a welding base, and a positioning fixture. The welding base is disposed on one side of the body, and the welding head is connected to the body and positioned above the welding base. The welding base includes a welding station, on which a first groove and a second groove are provided. The first groove communicates with the second groove. The first groove is used to place a battery cell, and the second groove is used to place a first tab. The positioning fixture is disposed above the first groove and detachably connected to the welding station. The positioning fixture and the second groove are used to fix a second tab.

[0006] Optionally, the end of the first groove away from the second groove has a notch.

[0007] Optionally, limit holes are provided on both sides of the first groove, and protrusions are provided on the positioning fixture at the positions corresponding to the limit holes, and the protrusions are detachably connected to the limit holes.

[0008] Optionally, the positioning fixture is provided with a first limiting groove and a second limiting groove at the position corresponding to the second groove, and the second limiting groove is connected to the first limiting groove.

[0009] A second aspect of the present invention provides a method for welding tabs of a pouch battery, which uses the aforementioned pouch battery tab welding apparatus and includes the following welding steps:

[0010] Step 1: Place the battery cell into the first groove, bend the first tab so that the large surface of the first tab changes from vertical to horizontal and contacts the second groove of the soldering station;

[0011] Step 2: Insert the protrusion of the positioning fixture into the limiting hole of the welding station;

[0012] Step 3: Place one end of the second electrode tab in the second limiting groove of the positioning fixture, and extend the other end of the second electrode tab into the second groove of the welding station;

[0013] Step 4: Start the welding head and weld the first electrode tab to the second electrode tab.

[0014] Optionally, step 3 further includes attaching tab adhesive to the outside of the portion of the second tab located within the first limiting groove.

[0015] Optionally, step 4 may further include the following steps:

[0016] Step 41: Trim off the excess parts of the first and second electrodes;

[0017] Step 42: Fold the first and second electrodes 90° each to complete the deflection welding.

[0018] Optionally, the first electrode is the inner electrode, and the second electrode is the outer electrode.

[0019] Optionally, multiple first electrodes are provided, and multiple second electrodes are also provided accordingly.

[0020] A third aspect of the present invention provides a battery prepared by the tab welding method for pouch batteries described above.

[0021] According to the electrode welding device for soft-pack batteries provided by the present invention, by using the above-mentioned welding device to weld the first electrode and the second electrode, not only is the welding speed fast and the yield high, but it can also significantly improve the battery breakage and electrode pulling situation, and at the same time reduce the internal resistance of the cell by 15%. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the electrode tab welding device for a soft-pack battery provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the positioning fixture in the electrode tab welding device for a soft-pack battery according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of welding tabs in a tab welding device for a soft-pack battery according to an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the tab bonding adhesive in the tab welding device for a soft-pack battery provided in an embodiment of the present invention;

[0027] Figure 5 This is a top view schematic diagram of the battery cell after the tab adhesive is applied according to an embodiment of the present invention;

[0028] Figure 6 This is a top view schematic diagram of the battery cell after the second electrode tab has been welded according to an embodiment of the present invention;

[0029] Figure 7 This is a bottom view schematic diagram of the battery cell after the second electrode tab has been welded according to an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of a battery cell provided in an embodiment of the present invention, showing the excess portions of the first and second tabs cut off;

[0031] The reference numerals in the accompanying drawings are as follows:

[0032] 1-Main body; 2-Welding head; 3-Welding base; 31-Welding station; 311-First groove; 312-Second groove; 313-Notch; 314-Limiting hole; 4-Positioning fixture; 41-Protrusion; 42-First limiting groove; 43-Second limiting groove; 5-Electrode adhesive; 6-Battery cell; 61-First electrode; 62-Second electrode. Detailed Implementation

[0033] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0034] In the description of this invention, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do 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. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 based on the specific circumstances.

[0036] like Figure 1 As shown, in one embodiment, the first aspect of the present invention provides a tab welding device for a soft-pack battery, including a body 1, a welding head 2, a welding seat 3, and a positioning fixture 4. The welding seat 3 is disposed on one side of the body 1, and the welding head 2 is connected to the body 1 and is located above the welding seat 3. The welding seat 3 includes a welding platform 31, on which a first groove 311 and a second groove 312 are provided. The first groove 311 communicates with the second groove 312. The first groove 311 is used to place a battery cell 6, and the second groove 312 is used to place a first tab 61. The positioning fixture 4 is disposed above the first groove 311 and is detachably connected to the welding platform 31. The positioning fixture 4 and the second groove 312 are used to fix the second tab 62.

[0037] Specifically, one end of the first tab 61 is connected to one end of the lower surface of the battery cell 6, and the other end of the first tab 61 extends to a position flush with the upper surface of the battery cell 6 and is bent. After bending, part of the first tab 61 fits against the end of the battery cell 6, and the other part of the first tab 61 is flush with the upper surface of the battery cell 6. The battery cell 6 is placed in the first groove 311, the size of the first groove 311 is the same as the size of the battery cell 6, and the first tab 61 is located in the second groove 312. The positioning fixture 4 is connected to the welding station 31, and the second tab 62 is placed between the positioning fixture 4 and the second groove 312. The first tab 61 and the second tab 62 are welded by ultrasonic welding.

[0038] This application uses the above-mentioned welding device to weld the first tab 61 and the second tab 62, which not only has a fast welding speed and high yield, but also can greatly improve the battery breakage and electrode pulling situation, and at the same time reduce the internal resistance of the cell 6 by 15%.

[0039] like Figure 1 As shown, in one embodiment, the end of the first groove 311 away from the second groove 312 is provided with a notch 313.

[0040] Specifically, the notch 313 is U-shaped, and the other end of the notch 313 extends into the first groove 311. The notch 313 facilitates the placement of the battery cell 6 into the first groove 311, making it convenient to replace the battery cell 6 after the soldering is completed.

[0041] like Figures 1-2 As shown, in one embodiment, limit holes 314 are provided on both sides of the first groove 311, and protrusions 41 are provided at the positions corresponding to the limit holes 314 of the positioning fixture 4. The protrusions 41 and the limit holes 314 are detachably connected.

[0042] Specifically, by embedding the protrusion 41 into the limiting hole 314, the positioning clamp 4 and the welding station 31 are fixed in the direction of the plane where the welding station 31 is located, so as to prevent the positioning clamp 4 from moving along the plane where the welding station 31 is located, thereby placing the second electrode 62 between the positioning clamp 4 and the second groove 312 and limiting the second electrode 62.

[0043] like Figure 2 As shown, in one embodiment, the positioning clamp 4 is provided with a first limiting groove 42 and a second limiting groove 43 at the position corresponding to the second groove 312, and the second limiting groove 43 is connected to the first limiting groove 42.

[0044] Specifically, the first limiting groove 42 is used to limit the position of the tab adhesive 5, and the second limiting groove 43 is used to limit the position of the end of the second tab 62. The tab adhesive 5 is adhered to the outside of the second tab 62 and the second tab 62 is fixed to the first tab 61. The welding position is located in the area of ​​the surface of the second tab 62 that is not covered by the tab adhesive 5.

[0045] like Figures 3-8 As shown, in one embodiment, the second aspect of the present invention provides a method for welding the tabs of a pouch battery, which uses the aforementioned pouch battery tab welding apparatus for welding, and includes the following welding steps:

[0046] Step 1: Place the battery cell 6 into the first groove 311, bend the first tab 61 so that the large surface of the first tab 61 changes from vertical to horizontal and contacts the second groove 312 of the soldering station 31.

[0047] Step 2: Insert the protrusion 41 of the positioning fixture 4 into the limiting hole 314 of the welding station 31;

[0048] Step 3: Place one end of the second electrode 62 into the second limiting groove 43 of the positioning fixture 4, and extend the other end of the second electrode 62 into the second groove 312 of the welding station 31;

[0049] Step 4: Start welding head 2 and weld the first electrode 61 to the second electrode 62.

[0050] Specifically, the battery cell 6 is placed in the first groove 311. At this time, one end of the first tab 61 is connected to one end of the lower surface of the battery cell 6, and the other end of the first tab 61 is attached to the end of the battery cell 6 and extends in a direction perpendicular to the upper surface of the battery cell 6. The first tab 61 is located between the first groove 311 and the second groove 312. Then, the other end of the first tab 61 is bent at a position flush with the upper surface of the battery cell 6. After bending, part of the first tab 61 is attached to the end of the battery cell 6, and the other part of the first tab 61 is located in the second groove 312.

[0051] Next, the protrusion 41 of the positioning fixture 4 is inserted into the limiting hole 314, so that the positioning fixture 4 and the welding station 31 are fixed in the direction of the plane where the welding station 31 is located. The second electrode 62 is placed between the positioning fixture 4 and the second groove 312, and the first electrode 61 and the second electrode 62 are welded by ultrasonic welding.

[0052] This application uses the above-mentioned welding device to weld the first tab 61 and the second tab 62, which not only has a fast welding speed and high yield, but also can greatly improve the battery breakage and electrode pulling situation, and at the same time reduce the internal resistance of the cell 6 by 15%.

[0053] like Figures 4-5 As shown, in one embodiment, step 3 further includes attaching tab adhesive 5 to the outside of the portion of the second tab 62 located within the first limiting groove 42.

[0054] Specifically, the first limiting groove 42 is used to limit the position of the tab adhesive 5. The tab adhesive 5 is placed in the first limiting groove 42 and adhered to the outside of the second tab 62, thereby fixing the second tab 62 to the first tab 61. The welding position is located in the area of ​​the second tab 62 surface that is not covered by the tab adhesive 5.

[0055] like Figures 6-8 As shown, in one embodiment, step 4 further includes the following steps:

[0056] Step 41: Cut off the excess parts of the first electrode tab 61 and the second electrode tab 62;

[0057] Step 42: Fold the first tab 61 and the second tab 62 by 90° to complete the deflection welding.

[0058] In step 41, the excess parts of the first electrode tab 61 and the second electrode tab 62 are cut off to ensure that the length of the first electrode tab 61 and the second electrode tab 62 after folding is moderate and easy to connect with the pole post.

[0059] In step 42, the first tab 61 and the second tab 62 are folded toward the thickness of the cell 6 by 90°, thereby reducing the volume occupied by the first tab 61 and the second tab 62 in the length direction of the cell 6, thereby relatively increasing the length of the cell 6 and improving the battery capacity.

[0060] like Figures 6-8 As shown, in one embodiment, the first electrode 61 is the inner electrode and the second electrode 62 is the outer electrode.

[0061] Specifically, the first tab 61 is connected to the cell 6, and the second tab 62 is welded to the first tab 61 after the first tab 61 is bent. This not only has a fast welding speed and high yield, but also can greatly improve the situation of battery breakage and electrode pulling, while reducing the internal resistance of the cell 6 by 15%.

[0062] like Figures 6-8 As shown, in one embodiment, multiple first tabs 61 are provided, and multiple second tabs 62 are also provided accordingly.

[0063] Specifically, one or more tabs can be provided on the same end of the battery cell 6. Correspondingly, the number of second tabs 62 is the same as that of first tabs 61, so that after the first tab 61 is bent, the second tab 62 is welded to the corresponding first tab 61.

[0064] A third aspect of the present invention provides a battery prepared by the above-described method for welding the tabs of a pouch cell.

[0065] The battery described in this application is a lithium-ion battery, and its negative electrode is a silicon-based negative electrode. The welding method described in this application is used to weld the first tab 61 and the second tab 62. This method not only has a fast welding speed and high yield, but also avoids the problems of high expansion rate of silicon negative electrode, severe tab pulling, and wrinkling of electrode sheet, which would lead to increased internal resistance of battery and lithium plating. If the expansion is large, the pulling will be more severe and may even lead to tab breakage. This method significantly improves the battery breakage and electrode pulling situation, and at the same time reduces the internal resistance of cell 6 by 15%, thereby improving the production yield of lithium-ion batteries with silicon negative electrodes.

[0066] 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, and improvements 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 welding tabs of a pouch battery, comprising welding using a pouch battery tab welding device, characterized in that: The electrode welding device includes a body, a welding head, a welding base, and a positioning fixture. The welding base is disposed on one side of the body, and the welding head is connected to the body and positioned above the welding base. The welding base includes a welding platform with a first groove and a second groove. The first groove communicates with the second groove. The first groove is used to place a battery cell, and the second groove is used to place a first electrode. The positioning fixture is disposed above the first groove and detachably connected to the welding platform. The positioning fixture and the second groove are used to fix a second electrode. Limiting holes are provided on both sides of the first groove, and protrusions are provided on the positioning fixture at positions corresponding to the limiting holes. The protrusions are detachably connected to the limiting holes. The positioning fixture has a first limiting groove and a second limiting groove at positions corresponding to the second groove. The second limiting groove communicates with the first limiting groove. The electrode welding method includes the following welding steps: Step 1: Place the battery cell into the first groove. At this time, one end of the first tab is connected to one end of the lower surface of the battery cell, and the other end of the first tab is attached to the end of the battery cell and extends in a direction perpendicular to the upper surface of the battery cell. The first tab is located between the first groove and the second groove. Then, bend the other end of the first tab at a position flush with the upper surface of the battery cell. After bending, part of the first tab is attached to the end of the battery cell, so that the large surface of the first tab changes from vertical to horizontal. The other part of the first tab is located in the second groove and contacts the second groove of the soldering station. Step 2: Insert the protrusion of the positioning fixture into the limiting hole of the welding station; Step 3: Place one end of the second electrode tab in the second limiting groove of the positioning fixture, and extend the other end of the second electrode tab into the second groove of the welding station; Step 4: Start the welding head and weld the first electrode tab to the second electrode tab; Cut off the excess parts of the first and second electrodes; Fold the first and second tabs toward the thickness of the battery cell, each folded 90°, to complete the deflection welding.

2. The electrode tab welding method for a soft-pack battery according to claim 1, characterized in that: The end of the first groove away from the second groove has a notch.

3. The electrode tab welding method for a soft-pack battery according to claim 1, characterized in that: Step 3 further includes attaching electrode adhesive to the outside of the portion of the second electrode located within the first limiting groove.

4. The electrode tab welding method for a soft-pack battery according to claim 1, characterized in that: The first electrode is the inner electrode, and the second electrode is the outer electrode.

5. The electrode tab welding method for a soft-pack battery according to claim 1, characterized in that: Multiple first electrodes are provided, and multiple second electrodes are also provided accordingly.

6. A battery, characterized in that: The battery is prepared by the tab welding method for a pouch battery as described in any one of claims 1-5.

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