Lithium Electrode Tab Cooling for Stable Ultrasonic Welding

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Solution Overview

Problem

Lithium metal electrodes in next-generation batteries face issues of low mechanical strength, leading to deformation, poor coupling strength with lead tabs, and sticking during manufacturing processes, particularly in welding, which affects manufacturing efficiency and quality.

Innovation Solution

A method and system for manufacturing electrode assemblies that involve cooling and hardening the lithium electrode tab, using a cooling apparatus with coolant flow paths, followed by ultrasonic welding to couple the tab with a lead tab, ensuring mechanical stiffness and preventing sticking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal is used as a negative electrode without a metal current collector, then battery energy density is improved, but mechanical strength decreases leading to deformation and sticking issues

Engineering Contradiction:
Improveenergy densityVSAvoidmechanical strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent applies parameter changes by controlling the temperature of the lithium metal during the welding process. By maintaining the lithium metal at a temperature below a specific threshold (e.g., room temperature or lower), the material properties change to provide sufficient mechanical strength and prevent sticking, while still achieving the desired coupling between electrode tab and lead tab

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If lithium metal electrode tab is pressed and spread during welding process, then coupling area is increased, but coupling strength decreases and sticking occurs

Engineering Contradiction:
Improvecoupling areaVSAvoidcoupling strength
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The patent uses temperature as a controlling parameter to prevent the lithium metal from deforming excessively during welding. By maintaining appropriate temperature conditions, the lithium metal retains its structural integrity while still achieving adequate contact area for coupling, thus preventing both insufficient coupling and sticking issues

Inventive Principle:
Principle #35Parameter changes

3Strength

If cooling apparatus with press parts is used to cool and press electrode tab, then mechanical stiffness is improved, but device complexity increases

Engineering Contradiction:
Improvemechanical stiffnessVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the cooling function and pressing function into a single integrated cooling apparatus. The press parts are incorporated directly into the cooling device, allowing simultaneous cooling and pressing of the lithium metal electrode tab. This reduces the number of separate devices needed while achieving the desired mechanical stiffness

Inventive Principle:
Principle #5Merging (Combining)

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 coupling quality and mechanical stiffness, preventing lithium sticking and improving manufacturing efficiency by ensuring strong and stable connections between electrode and lead tabs.

Implementation Method 1

a cooling step, in which the electrode tab is cooled

Methodology Applied
Scientific EffectCooling: Cooling

Implementation Method 2

the electrode tab may be cooled in a state pressed by a cooling apparatus

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

a connecting step, in which the cooled electrode tab and a lead tab are coupled to each other

Methodology Applied
Scientific EffectUltrasonic welding: Welding

Data Source

PatentEP4700971A1Method for manufacturing electrode assembly, battery cell manufactured using same, and system for manufacturing electrode assembly
Publication Date: 2026.02.25 LG ENERGY SOLUTION LTD
  • EP4700971A1 patent drawingFigure 1
  • EP4700971A1 patent drawingFigure 2
  • EP4700971A1 patent drawingFigure 3

AI summary

Provided is a method for manufacturing electrode assembly, the method comprising: a preparation step of aligning electrode tabs of one or more first electrode plates; a cooling step of cooling the electrode tabs; and a connecting step of coupling the cooled electrode tabs and lead tabs to each other.