Battery Stack Coating Peeling by Cold Shrinkage Delamination

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Solution Overview

Problem

The existing manufacturing processes for electrochemical stacks in batteries face challenges such as damage to layers during coating removal, heat sensitivity of polymer-based materials, and incompatibility with chemical treatments, leading to production scrap and potential battery breakdown.

Innovation Solution

A roll-to-roll manufacturing process that uses controlled cooling and mechanical action to detach coatings from electrolyte layers, minimizing mechanical stress and avoiding heat or chemical treatments, by applying cold fluids like liquid nitrogen and using thermoelectric effects to shrink and then expand the coatings, allowing for gentle separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heating is used to detach the coating, then the coating can be removed, but the polymer-based binders and active materials are damaged due to heat sensitivity

Engineering Contradiction:
Improvecoating removal effectivenessVSAvoidheat damage to materials
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the temperature parameter from heating to cooling. By applying cold treatment (e.g., liquid nitrogen at -196°C or cold air at -40°C to -80°C), the coating and substrate are cooled to create thermal contraction differences, enabling coating detachment without exposing heat-sensitive polymer materials to damaging temperatures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention utilizes phase transition of cold media (e.g., liquid nitrogen evaporating to gas) to achieve cooling effect. The rapid phase change from liquid to gas provides intense cooling that shrinks the coating, creating detachment from the substrate without requiring heating.

Inventive Principle:
Principle #36Phase transitions

2Reliability

If acidic or alkaline chemical treatment is used to detach the coating, then the coating can be removed, but sulfide materials react with water to release toxic gases

Engineering Contradiction:
Improvecoating removal effectivenessVSAvoidtoxic gas release
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention replaces chemical treatment mechanisms with physical cooling mechanisms. Instead of using acidic or alkaline chemicals that cause harmful reactions with sulfide materials, the invention uses cold media (liquid nitrogen or cold air) to physically shrink the coating and enable detachment, eliminating toxic gas generation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses inert or non-reactive cold media (liquid nitrogen or dry air) to create a chemically inert environment during coating detachment. These media do not react with sulfide materials or other battery components, preventing harmful chemical reactions and toxic gas release.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Reliability

If strong mechanical action is used to detach the coating, then the coating can be removed, but the material layers are damaged causing short circuits

Engineering Contradiction:
Improvecoating removal effectivenessVSAvoidlayer integrity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention applies cold treatment before mechanical detachment to preliminarily shrink the coating and create initial separation from the substrate. This preliminary action reduces the adhesion strength, allowing subsequent gentle mechanical action (such as blade insertion or rolling) to detach the coating without applying excessive force that would damage the underlying material layers.

Inventive Principle:
Principle #10Preliminary action

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

This process enhances productivity while reducing coating removal issues, minimizing mechanical damage and avoiding heat or chemical reactions, thus improving the reliability and efficiency of electrochemical stack production.

Implementation Method 1

a successive application of cold in time to portions of the first coating to obtain cooling and shrinkage of said portions

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 2

the application of a first thermoelectric effect junction to said portions, said first junction being configured to produce cold and said cooling being obtained by thermal conduction between the first junction and said portions

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Implementation Method 3

the mechanical action comprising an implementation of at least one blade located between the first coating and the first electrolyte layer to separate the first coating and the first electrolyte layer

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP4333139A1Method for producing an electrochemical battery stack, comprising a cold input for peeling a coating
Publication Date: 2024.03.06 SAFT GRP SA
  • EP4333139A1 patent drawingFigure 1
  • EP4333139A1 patent drawingFigure 2
  • EP4333139A1 patent drawingFigure 3

AI summary

A roll-to-roll manufacturing process for an electrochemical stack (10), comprising: - obtaining a stack (34) comprising, successively in a stacking direction (Δ), a first electrode (14), a first layer of electrolyte (16), a first coating (36), - detaching the first coating to obtain a first free surface (38), - fixing a second electrode (20) of opposite polarity on the first free surface.The delamination of the first coating includes: - the successive application of cold over time to successive portions of the first coating to obtain cooling and shrinkage of the portions, and - a mechanical action to successively detach each of the portions after shrinkage, the mechanical action including a traction exerted on the first coating and having a component in the stacking direction, and/or including the implementation of at least one blade located between the first coating and the first layer of electrolyte.