Lithium-Metal Solid-State Electrode Assembly for Electrolyte Protection

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Solution Overview

Problem

All-solid-state batteries using lithium metal for a negative electrode face issues with damage to the solid electrolyte layer due to volume changes in the negative electrode during charging/discharging, leading to potential short circuits and reduced safety.

Innovation Solution

An electrode assembly design featuring a protective layer with a frame shape between the negative electrode and solid electrolyte layer, where the positive electrode is indirectly contacted through the electrolyte, and a polymer-based protective layer with higher mechanical strength than the electrolyte, preventing damage from lithium plating-induced steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the solid electrolyte layer is made thin to increase energy density, then energy density is improved, but mechanical strength deteriorates and the layer becomes more susceptible to damage

Engineering Contradiction:

Improveenergy densityVSAvoidmechanical strength of solid electrolyte layer

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent employs a composite structure consisting of the solid electrolyte layer combined with a protective layer having higher mechanical strength. This composite configuration allows the solid electrolyte layer to maintain thin dimensions for high energy density while the protective layer compensates for the reduced mechanical strength, preventing damage from lithium plating and volume changes.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the solid electrolyte layer is made sticky due to high viscosity to reduce interfacial resistance, then interfacial resistance is reduced, but mechanical strength deteriorates and the layer becomes more prone to damage

Engineering Contradiction:

Improveinterfacial resistanceVSAvoidmechanical strength of solid electrolyte layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent creates a composite system where the solid electrolyte layer with high viscosity provides low interfacial resistance for reliable electrochemical performance, while the protective layer with higher mechanical strength compensates for the vulnerability caused by the sticky, viscous nature of the electrolyte layer.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If lithium metal is used for negative electrode to achieve high capacity, then capacity is improved, but volume change during charging/discharging increases causing damage to solid electrolyte layer

Engineering Contradiction:

ImprovecapacityVSAvoidintegrity of solid electrolyte layer

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by introducing a protective layer with higher mechanical strength before the solid electrolyte layer can be damaged. This protective layer anticipates and absorbs the mechanical stress from lithium metal volume changes during charging/discharging, preventing damage to the solid electrolyte layer while maintaining high capacity.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent uses a composite structure where lithium metal provides high capacity in the negative electrode, and the protective layer with higher mechanical strength compensates for the volume change issues, creating a resilient system that maintains both high capacity and reliability.

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If the area of negative electrode is made larger than positive electrode to align electrodes during manufacturing, then manufacturing alignment is improved, but lithium plating occurs on uncovered regions causing steps and damage

Engineering Contradiction:

ImprovealignmentVSAvoidintegrity of solid electrolyte layer

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by placing a protective layer that extends beyond the positive electrode edges. This protective layer anticipates the formation of steps from lithium plating on uncovered negative electrode regions and provides mechanical support to prevent solid electrolyte layer damage.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The protective layer acts as an intermediary element between the negative electrode and the solid electrolyte layer. It mediates the mechanical stress from lithium plating and volume changes, protecting the solid electrolyte layer from damage while allowing the manufacturing alignment approach to continue.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 protective layer supports the electrolyte layer, maintaining its integrity and preventing damage from lithium plating-induced steps, enhancing safety and reducing the risk of short circuits.

Implementation Method 1

a polymer-based protective layer with higher mechanical strength than the electrolyte, preventing damage from lithium plating-induced steps

Methodology Applied

Scientific EffectMechanical strength:

Implementation Method 2

there is a very large volume change of the negative electrode due to lithium stripping/plating

Methodology Applied

Scientific EffectLithium stripping/plating:

Data Source

PatentUS20250343223A1All-solid-state battery using lithium metal for negative electrode

Publication Date: 2025.11.06 LG ENERGY SOLUTION LTD

AI summary

Disclosed is an electrode assembly for an all-solid-state battery with improved safety, and more particularly, to an electrode assembly of a new structure designed to prevent the damage of a solid electrolyte layer caused by a step formed in a negative electrode layer due to changes in thickness of the negative electrode layer, such as an increase or decrease in thickness at part of the negative electrode layer, during charging/discharging. The electrode assembly is characterized by comprising a protective layer having an opening, interposed between the negative electrode and the solid electrolyte layer.