Single-position sequential laser welding system

Patent metadata

Field	Value
Publication number	US-2018281110-A1
Application number	US-201715474860-A
Country	US
Kind code	A1
Filing date	Mar 30, 2017
Priority date	Mar 30, 2017
Publication date	Oct 4, 2018
Grant date	—

Abstract

Methods and systems for sequentially laser welding terminal tabs of a battery cell to corresponding terminal tabs of a busbar are described using a single laser position and path. The terminal tabs of a battery cell are aligned in contact with terminal tabs of a busbar. A laser welder, from a first position, generates a laser weld beam at a first diameter welding the first terminal tab of the battery cell to the first terminal tab of the busbar. Next, the laser weld beam is narrowed, reducing the first diameter to a smaller second diameter. Without moving the laser welder from the first position, the narrowed laser weld beam burns a hole through the welded first set of terminal tabs, traverses a gap toward a second set of terminal tabs behind the first set and welds the second set together.

First claim

What is claimed is:

1 . A laser welding system, comprising:
a laser welder configured to emit a laser weld beam along a linear laser path in an emission direction; a controller, configured to:
activate an emission of the laser weld beam from the laser welder at a first beam diameter in the emission direction and along the linear laser path toward a first and second substrate in contact with one another, wherein the emission of the laser weld beam forms a welded connection between the first and second substrate after a first period of time;
narrow a focus of the laser weld beam changing the first beam diameter to a smaller second beam diameter, wherein the narrowed laser weld beam burns a hole through a portion of the welded connection and the first and second substrates after a second period of time; and
maintain the laser welder in an emitting state such that the narrowed laser weld beam is directed through the hole and along the linear laser path in the emission direction toward a third and fourth substrate in contact with one another, wherein the emission of the narrowed laser weld beam welds the third and fourth substrate together after a third period of time.

2 . The laser welding system of claim 1 , wherein the first and second substrates remain connected together at a periphery of the hole burned through the first and second substrates.

3 . The laser welding system of claim 1 , wherein an air gap separates the first and second substrates from the third and fourth substrates.

4 . The laser welding system of claim 3 , wherein the first and second substrates are in a line with the third and fourth substrates.

5 . The laser welding system of claim 4 , wherein the first substrate is first terminal tab of a battery cell, the second substrate is a first terminal tab of a busbar, the third substrate is a second terminal tab of the battery cell, and the fourth substrate is a second terminal tab of the busbar,

6 . The laser welding system of claim 5 , wherein prior to forming the welded connection, the first and second terminal tabs of the battery cell are separate from the first and second terminal tabs of the busbar.

7 . The laser welding system of claim 6 , further comprising:
an actuator system configured to position the first and second terminal tabs of the battery cell in contact with and overlapping a portion of the first and second terminal tabs of the busbar prior to activating the emission of the laser weld beam.

8 . A laser welding method, comprising:
activating, via a controller, a laser welder causing the laser welder to emit a laser weld beam at a first beam diameter along a linear laser path and in an emission direction toward a first substrate; welding, via the emitted laser weld beam, the first substrate to a second substrate in contact with and overlapping the first substrate at a first weld area; narrowing, via the controller, the laser weld beam from the first beam diameter to a smaller second beam diameter; burning, via the narrowed laser weld beam, a hole through the welded first and second substrate inside the first weld area; emitting the narrowed laser weld beam through the hole burned in the welded first and second substrate along the linear laser path to a third substrate spaced apart from the first and second substrate; and welding, via the narrowed laser weld beam, the third substrate to a fourth substrate rn contact with and overlapping the third substrate at a second weld area,

9 . The laser welding method of claim 8 , wherein narrowing the laser weld beam further comprises:
determining, via the controller, a desired size for the hole to be burned through the first and second substrates; and focusing, via the controller, the laser weld beam to the second beam diameter, wherein the second beam diameter is smaller than a diameter of the first weld area and configured to create the determined desired size for the hole.

10 . The laser welding method of claim 9 , wherein determining the desired size for the hole to be burned through the first and second substrates further comprises:
determining a cross-sectional area for a connection between the first and second substrate; determining an overload protection cross-sectional area less than the cross-sectional area for the connection between the first and second substrate; determining a difference between the overload protection cross-sectional area and the cross-sectional area; and sizing the desired hole size to include the difference determined.

11 . The laser welding method of claim 9 , further comprising:
maintaining a position of the laser welder between welding the first and second substrates and welding the third and fourth substrates.

12 . The laser welding method of claim 11 , wherein prior to activating the laser welder, the method further comprises:
positioning, via an actuation system, the first substrate into contact with the second substrate and the third substrate with the fourth substrate.

13 . The laser welding method of claim 11 , wherein prior to activating the laser welder, the method further comprises:
aligning, via an actuation system, a portion of the first substrate, second substrate, third substrate, and fourth substrate in a line with the linear laser path.

14 . A method of manufacturing a laser welded battery cell and busbar connection, comprising:
arranging first and second terminal tabs of a battery cell in contact with corresponding first and second terminal tabs of a busbar; positioning a portion of the contacting terminal tabs in a single linear laser path; activating an emission of a laser weld beam from a laser welder at a first beam diameter in an emission direction along the linear laser path toward the first terminal tab of the battery cell in contact with the first terminal tab of the busbar; welding the first terminal tab of the battery cell to the first terminal tab of the busbar at a first weld area; narrowing the laser weld beam from the first beam diametero a smaller second beam diameter; burning a hole through the welded first e tabs of the battery cell and busbar inside the first weld area; emitting the narrowed laser weld beam through the hole and along the linear laser path to the second terminal tab of the battery cell spaced apart from the first terminal tabs of the battery cell and busbar; and welding, via the narrowed laser weld beam, the second terminal tab of the battery cell to the second terminal tab of the busbar at a second weld area.

15 . The method of manufacturing of claim 14 , wherein the first terminal tabs of the battery cell and busbar remain connected together at a periphery of the hole burned through the first terminal tabs of the battery cell and busbar.

16 . The method of manufacturing of claim 15 , wherein an air gap separates the first terminal tabs of the battery cell and busbar from the second terminal tabs of the battery cell and busbar.

17 . The method of manufacturing of claim 16 , wherein narrowing the laser weld beam further comprises:
determining, via the controller, a desired size for the hole to be burned through the first terminal tabs of the battery cell and busbar; and focusing, via the controller, the laser weld beam to the second beam diameter, wherein the second beam diameter is smaller than a diameter of the first weld area and configured to create the determined desired size for the hole.

18 . The method of manufacturing of claim 17 , wherein determining the desired size for the hole to be burned through the first terminal

Assignees

• Nextev Usa Inc

Inventors

• Newman Austin L

Classifications

• H01M50/516

  by welding, soldering or brazing · CPC title

• H01M50/55

  on the same side of the cell · CPC title

• H01M10/0413

  Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes · CPC title

• B23K26/702

  Auxiliary equipment · CPC title

• H01M10/0404

  Machines for assembling batteries · CPC title