All-Solid-State Battery Stacking for Low Interface Resistance

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Solution Overview

Problem

All-solid-state batteries face challenges with high surface resistance of positive and negative electrodes in contact with the solid electrolyte, leading to lower lifespan and power output compared to conventional liquid electrolyte batteries.

Innovation Solution

The solution involves an all-solid-state battery design with a specific stacking configuration of unit cells, where the surface resistance of the negative and positive electrodes in contact with the solid electrolyte is reduced to 3 mΩ/cm2 or less, achieved through a method involving release films and pressurization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfide-based solid electrolyte is used to eliminate organic solvents and improve safety, then safety is improved, but ionic conductivity and electrical resistance increase leading to lower lifespan and power output

Engineering Contradiction:

ImprovesafetyVSAvoidpower output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent applies different surface treatments to different regions of the electrode. Specifically, the surface of the electrode in contact with the solid electrolyte is treated to have low surface resistance (3 mΩ/cm2 or less), while other regions maintain their original properties. This local differentiation resolves the contradiction by optimizing the critical interface region for electrical conductivity without compromising the overall safety benefits of using sulfide-based solid electrolyte.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the surface resistance parameter of the electrode from its conventional value to 3 mΩ/cm2 or less through surface treatment. This parameter change at the electrode surface improves ionic conductivity and electrical resistance at the critical electrode-electrolyte interface, thereby enhancing power output and lifespan while maintaining the safety advantages of solid electrolyte.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If electrodes are pressurized in a roll-to-roll fashion to simplify manufacturing, then ease of manufacture is improved, but the interior becomes porous and interfacial contact becomes difficult

Engineering Contradiction:

Improveease of manufactureVSAvoidinterfacial contact

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies surface treatment to the electrode before assembly and pressurization, preliminarily optimizing the surface properties to achieve low surface resistance. This preliminary action ensures that even after roll-to-roll pressurization, the electrode maintains good interfacial contact with the solid electrolyte, resolving the contradiction between ease of manufacture and manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional overcoating method is used to fabricate electrodes, then ease of manufacture is improved, but surface resistance increases causing degradation of all-solid-state batteries

Engineering Contradiction:

Improveease of manufactureVSAvoidbattery performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the surface resistance parameter through surface treatment, achieving 3 mΩ/cm2 or less. This parameter change improves battery performance and reliability while maintaining the simplicity of the overcoating fabrication method, thus resolving the contradiction between ease of manufacture and battery performance.

Inventive Principle:

Principle #35Parameter changes

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 approach results in improved performance of the all-solid-state battery by reducing surface resistance, enhancing electrode alignment, and simplifying the fabrication process, ultimately leading to better lifespan and power output.

Implementation Method 1

sulfide-based all-solid batteries are gaining attention because of their superior lithium ion conductivity

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

a surface resistance of the negative electrode in contact with the solid electrolyte layer and the positive electrode in contact with the solid electrolyte layer is 3 mΩ/cm2 or less, achieved through a method involving release films and pressurization

Methodology Applied

Scientific EffectPressurization: Pressurisation

Data Source

PatentUS20250149641A1All-solid-state battery and manufacturing method therefor

Publication Date: 2025.05.08 LG ENERGY SOLUTION LTD

AI summary

An all-solid-state battery and a method for manufacturing the same are provided. The all-solid-state battery comprises a first unit cell comprising a current collector, a negative electrode, a solid electrolyte layer, and a positive electrode stacked sequentially; and a second unit cell comprising another said current collector, another said positive electrode, another said solid electrolyte layer, and another said negative electrode stacked sequentially, wherein the first and second unit cells are alternately stacked such that electrodes of a same polarity are located on both sides of the current collector, and a surface resistance of the negative electrode in contact with the solid electrolyte layer and the positive electrode in contact with the solid electrolyte layer in the first and second unit cells is 3 mΩ/cm2 or less.