Vacuum Fixture Laser Welding for High-Layer Battery Foils

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Solution Overview

Problem

Traditional laser welding methods for compliant sheets in battery foils, such as anodes and cathodes, suffer from air gaps and foil cutting, leading to poor weld quality and limited layer count due to the non-contact nature of laser welding, which restricts battery cell output.

Innovation Solution

A sealed fixture assembly with a vacuum mechanism is used to bring sheets into intimate contact, minimizing air gaps and ensuring consistent pressure, combined with laser welding parameters to achieve high-quality welds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If laser welding is used to weld compliant sheets, then the layer count can surpass 100 layers, but air gaps between foil sheets diminish weld quality and can cause inadvertent cutting of the foil

Engineering Contradiction:

Improvelayer countVSAvoidweld quality

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A vacuum fixture acts as an intermediary device between the laser welding system and the compliant sheets. The vacuum fixture removes air gaps from between the foil sheets during welding, ensuring intimate contact while allowing the laser beam to pass through the vacuum environment to weld more than 100 layers without causing inadvertent cutting or poor weld quality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The vacuum environment created by the vacuum fixture serves as an inert atmosphere that eliminates air between the compliant sheets. This vacuum environment prevents air gaps from interfering with the laser welding process, allowing high layer counts to be welded with maintained reliability and weld quality

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If a hollow clamp is used to secure foil stacks, then air gaps are minimized, but the clamp does not remove air gaps entirely and does not create consistent pressure throughout the foil stack

Engineering Contradiction:

Improveair gap minimizationVSAvoidpressure consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The mechanical clamp system is replaced with a vacuum-based system. Instead of using mechanical clamps that cannot provide consistent pressure throughout the foil stack, the vacuum fixture uses atmospheric pressure differential to uniformly press all sheets against the vacuum surface, ensuring consistent pressure and complete air gap removal across the entire welding area

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses vacuum pressure (pneumatics) to secure the foil stacks. The vacuum fixture creates a pressure differential that uniformly presses all compliant sheets against the vacuum surface, ensuring consistent pressure distribution throughout the entire foil stack, unlike mechanical clamps that create localized pressure points

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Quantity of substance

If traditional ultrasonic welding is used, then foil stacks are limited to 40-60 sheets due to thickness limitations, but this limitation caps battery cell output

Engineering Contradiction:

Improvelayer countVSAvoidbattery cell output

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

Ultrasonic welding is replaced with laser welding in a vacuum environment. This substitution removes the thickness limitation inherent in ultrasonic welding, allowing foil stacks to exceed 100 layers. The laser welding process, combined with vacuum-induced intimate contact, enables higher layer counts that directly increase battery cell output and productivity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method enhances weld quality by preventing sheet destruction and capillary action, increasing the number of layers that can be welded and improving electrical connections.

Implementation Method 1

A vacuum is used to remove the air between the sheets

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 2

a vacuum is used to bring the sheets into intimate contact with each other

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

a laser welder can then be utilized with the correct parameters in relation to the material of the foil to produce a proper weld

Methodology Applied

Scientific EffectLaser irradiation: Laser

Implementation Method 4

a laser welder can then be utilized with the correct parameters in relation to the material of the foil to produce a proper weld

Methodology Applied

Scientific EffectLocalized heating: Heating

Data Source

PatentUS20250281999A1Method and Apparatus to Laser Weld Compliant Sheets of Material

Publication Date: 2025.09.11 PHOTON APPLICATIONS LLC

AI summary

A method and apparatus for laser welding compliant sheets. Select a material for the sheets. Layer a selected number of sheets of the material to weld at a weld area. Assemble the sealed fixture with the plurality of sheets within the sealed fixture assembly. Create a vacuum or partial pressure within the sealed fixture assembly. Laser-weld the sheets at the weld area. An apparatus for performing the method is also presented.