Composite Active Material Particle Coating for All-Solid-State Battery Resistance

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Solution Overview

Problem

All-solid-state lithium ion batteries exhibit high resistance despite the use of composite active material particles, as moisture in these particles reacts with sulfide solid electrolytes, leading to performance inadequacies.

Innovation Solution

A composite active material particle with a moisture content of no more than 319 ppm is produced by coating an active material particle with a lithium ion conducting oxide and subjecting it to vacuum drying at 120° C to 300° C for at least 1 hour, reducing moisture content and suppressing reactions with sulfide solid electrolytes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vacuum drying is performed at high temperature to remove moisture, then battery resistance is reduced, but energy consumption increases

Engineering Contradiction:

Improvebattery resistanceVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The vacuum drying step is performed as a preliminary action before coating, which allows moisture removal to be completed in one dedicated step. This preliminary action approach consolidates the energy-intensive drying process into a single operation, making the overall process more energy-efficient while still achieving the goal of reducing battery resistance.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If moisture content in the composite active material particle is reduced, then sulfide solid electrolyte deterioration is suppressed, but the drying process complexity increases

Engineering Contradiction:

Improveelectrolyte stabilityVSAvoiddrying process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent simplifies the drying process by specifying a single set of parameters: vacuum drying at 400°C or higher. This clear parameter specification avoids the need for complex multi-stage drying processes while effectively removing moisture to prevent electrolyte deterioration, thus resolving the contradiction between electrolyte stability and process complexity.

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 significantly reduces battery resistance in all-solid-state lithium ion batteries by minimizing moisture-induced deterioration of sulfide solid electrolytes, maintaining high conductivity and improving battery performance.

Implementation Method 1

a lithium ion conducting oxide with which at least part of a surface of the active material particle is coated

Methodology Applied

Scientific EffectLithium ion conduction: Conduction (electrical)

Implementation Method 2

vacuum drying under predetermined conditions

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

vacuum drying under predetermined conditions

Methodology Applied

Scientific EffectVacuum: Vacuum

Data Source

PatentUS20220271296A1Composite active material particle, cathode, all-solid-state lithium ion battery, and methods for producing the same

Publication Date: 2022.08.25 TOYOTA JIDOSHA KK

AI summary

A composite active material particle that can reduce battery resistance when used in an all-solid-state lithium ion battery is disclosed. The composite active material particle comprises: an active material particle; and a lithium ion conducting oxide with which at least part of a surface of the active material particle is coated, wherein the moisture content in the composite active material particle is no more than 319 ppm.