All-Solid-State Battery Protective Layers Against Separator Tension

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Solution Overview

Problem

Sulfide-based all-solid-state batteries experience electrolyte layer cracking during the warm isostatic pressing process due to separator tension, especially in Z-stacking methods, which compromises the integrity and functionality of the battery.

Innovation Solution

An all-solid-state battery structure with protective layers on the electrode laminate, composed of materials like PI, PP, or PET, bonded via a primary coating or binder layer, and a separator wrapped in a zigzag manner to prevent direct pressure on the electrolyte layer, thereby preventing cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If Z-stacking method is used for unit cell stacking, then productivity and stacking density are improved, but the separator tension causes cracking of the electrolyte layer

Engineering Contradiction:

Improvestacking densityVSAvoidelectrolyte layer integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A protective layer is introduced as an intermediary component between the separator and the electrolyte layer. This protective layer absorbs the tension from the separator, preventing direct transmission of stress to the electrolyte layer and avoiding cracks while maintaining the Z-stacking configuration

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective layer is positioned in advance to cushion and distribute the tension forces that will occur during Z-stacking. By providing this preemptive protection, the electrolyte layer is shielded from the harmful effects of separator tension before cracking can occur

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Strength

If warm isostatic pressing process is applied to achieve electrode-solid electrolyte bonding, then interface bonding is improved, but the electrolyte layer becomes stiffened and prone to cracking

Engineering Contradiction:

Improveinterface bonding strengthVSAvoidelectrolyte layer flexibility

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The protective layer serves as a mediator that decouples the stiffening effect of WIP on the electrolyte layer from the bonding requirement. It allows the electrolyte layer to maintain its bond strength while the protective layer absorbs the mechanical stress, preventing crack formation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Force

If separator is wrapped tightly around electrode assembly, then electrode assembly is securely held, but tension from separator causes cracks in electrolyte layer

Engineering Contradiction:

Improveholding forceVSAvoidelectrolyte layer integrity

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The protective layer is positioned between the separator and the electrolyte layer to act as a stress-absorbing intermediary. It allows the separator to maintain its tight wrapping and holding force while preventing the transmission of tensile stress to the electrolyte layer, thus avoiding cracks

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4683027A1All-solid-state battery

Publication Date: 2026.01.21 LG ENERGY SOLUTION LTD

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AI summary

The present invention provides an all-solid-state battery comprising an electrode assembly comprising an electrode laminate comprising a positive electrode, an electrolyte film, and a negative electrode; and a pair of protective layers positioned on each of the sides of the positive electrode and the negative electrode; and a separator wrapped around the electrode assembly in a zigzag manner, such that the electrode assembly is positioned in a folded portion.