Welding systems and methods with knurled weld interfaces for metallic workpieces

Patent metadata

Field	Value
Publication number	US-11801574-B2
Application number	US-202016811627-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Mar 6, 2020
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

Presented are metalworking systems for joining metallic workpieces, methods for forming and welding such workpieces, and lithium-ion battery pouch cells with anodized aluminum tabs joined via knurling and laser welding. A method for laser welding abutting sections of a workpiece or stackup of workpieces includes receiving, via a workpiece support frame, one or more metallic workpieces each with a surface having applied thereto a treatment layer. This treatment layer releases a gas during welding. A metalworking device forms a knurl pattern into the workpiece surface with the treatment layer. The knurl pattern includes a network of channels, such as one or more series of mutually parallel, rectilinear vent channels, designed to exhaust therethrough the gas released from a welded section of the treatment layer. A laser welding device thereafter welds a joint region of the surface(s) of the one or more metallic workpiece with the knurl pattern.

First claim

What is claimed:

1. A method for laser welding one or more workpieces, the method comprising:
receiving a first metallic workpiece with a pair of opposing first workpiece surfaces each having applied thereto a first anodized layer, the first anodized layer releasing gas when welded;
forming, via a metalworking device, a first knurl pattern into each of the opposing first workpiece surfaces of the first metallic workpiece, the first knurl pattern including a first network of channels configured to exhaust therethrough the gas released from the first anodized layer, the first network of channels including first and second series of mutually parallel vent channels oriented at first and second oblique angles, respectively, with respect to a length of the first metallic workpiece, wherein the vent channels in the first series of mutually parallel vent channels are oriented at an angle of about 45 degrees to about 75 degrees with respect to the vent channels in the second series of mutually parallel vent channels; and
welding, via a laser welding device, a joint region of the opposing first workpiece surfaces of the first metallic workpiece with the first knurl pattern.

2. The method of claim 1 , wherein the vent channels in the first and second series of mutually parallel vent channels are recessed rectilinear channels interleaved with round-top protrusions.

3. The method of claim 1 , wherein the first metallic workpiece is a battery tab that includes a rectangular aluminum or aluminum alloy sheet metal blank, and the first knurl pattern extends longitudinally across the sheet metal blank.

4. The method of claim 3 , wherein the sheet metal blank includes opposing first and second minor edges extending between and connecting opposing first and second major edges, and wherein the first knurl pattern extends from the first minor edge to the second minor edge.

5. The method of claim 4 , wherein the first knurl pattern is set back from the first and second major edges.

6. The method of claim 1 , further comprising:
receiving a second metallic workpiece with a second workpiece surface having applied thereto a second anodized layer that releases gas when welded;
forming a second knurl pattern into the second workpiece surface of the second metallic workpiece, the second knurl pattern including a second network of channels configured to exhaust therethrough the gas released from the second anodized layer; and
stacking, prior to welding the joint region, the first and second metallic workpieces with at least one of the first workpiece surfaces and the second workpiece surface abutting each other and the first and second knurl patterns facing each other.

7. The method of claim 6 , wherein the second network of channels includes a third series of mutually parallel vent channels oriented at a third oblique angle with respect to a direction of travel of the laser welding device.

8. The method of claim 1 , wherein the first series of mutually parallel vent channels overlaps the second series of mutually parallel vent channels.

9. The method of claim 1 , wherein the vent channels in the first series of mutually parallel vent channels each has a depth of about 15% to about 65% a thickness of the first metallic workpiece.

10. A method of laser welding metallic workpieces, the method comprising:
receiving a first metallic workpiece with a first workpiece surface having applied thereto a first anodized layer that releases gas when welded;
receiving a second metallic workpiece with a second workpiece surface having applied thereto a second anodized layer that releases gas when welded;
forming, via a metalworking device, a first knurl pattern into the first workpiece surface of the first metallic workpiece, the first knurl pattern including a first set of channels configured to exhaust therethrough the gas released from the first anodized layer, the first set of channels including a first series of mutually parallel vent channels oriented at a first oblique angle with respect to a length of the first metallic workpiece;
forming, via the metalworking device, a second knurl pattern into the second workpiece surface of the second metallic workpiece, the second knurl pattern including a second set of channels configured to exhaust therethrough the gas released from the second anodized layer, the second set of channels including a second series of mutually parallel vent channels oriented at a second oblique angle with respect to a length of the second metallic workpiece;
stacking the first and second metallic workpieces with the first workpiece surface abutting the second workpiece surface such that the first knurl pattern faces the second knurl pattern and the vent channels in the first series of mutually parallel vent channels are oriented at an angle of about 45 degrees to about 75 degrees with respect to the vent channels in the second series of mutually parallel vent channels; and
welding, via a laser welding device, a joint region of the first and second workpiece surfaces with the first and second knurl patterns.

11. A metalworking system, comprising:
a metalworking device configured to form patterns into a first metallic workpiece, the first metallic workpiece including a pair of opposing first workpiece surfaces each having applied thereto a first anodized layer, the first anodized layer releasing gas when welded, the metalworking device being selectively operable to form a first knurl pattern into each of the opposing first workpiece surfaces of the first metallic workpiece, the first knurl pattern including a first network of channels configured to exhaust therethrough the gas released from the first anodized layer; and
a laser welding device operable to weld the first metallic workpiece, the laser welding device being selectively operable to weld a joint region of the opposing first workpiece surfaces of the first metallic workpiece with the first knurl pattern,
wherein the first network of channels includes a first series of mutually parallel vent channels and a second series of mutually parallel vent channels, the vent channels in the first series of mutually parallel vent channels being oriented at an angle of about 45 degrees to about 75 degrees with respect to the vent channels in the second series of mutually parallel vent channels.

12. The metalworking system of claim 11 , wherein the first series of mutually parallel vent channels is oriented at a first oblique angle with respect to a direction of travel of the laser welding device during the welding of the joint region.

13. The metalworking system of claim 11 , wherein the first series of mutually parallel vent channels is oriented at a first oblique angle with respect to a direction of travel of the laser welding device during the welding of the joint region, and the second series of mutually parallel vent channels is oriented at a second oblique angle, distinct from the first oblique angle, with respect to the direction of travel of the laser welding device.

14. The metalworking system of claim 11 , wherein the first metallic workpiece includes a rectangular aluminum or aluminum alloy sheet metal blank, and the first knurl pattern extends longitudinally across the sheet metal blank.

15. The metalworking system of claim 14 , wherein the sheet metal blank includes opposing first and second minor edges extending between and connecting opposing first and second major edges, and wherein the first knurl pattern extends from the first major edge to the second major edge.

16. The metalworking system of claim 11 , wherein the first series of mutually parallel v

Assignees

• Gm Global Tech Operations Llc

Inventors

• Chen Chih-Chang
• Disbro Jacob W
• Dietze Robert H

Classifications

• B23K28/02 Primary

  Combined welding or cutting procedures or apparatus · CPC title

• B23K26/244 Primary

  Overlap seam welding · CPC title

• B23K26/322

  involving coated metal parts (using absorbing layers on the workpiece B23K26/18) · CPC title

• B23K33/002

  Crimping or bending the workpieces at the joining area · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title