Solid Battery Electrode Binder Deposition via Solvent Mixture

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Solution Overview

Problem

The existing methods for producing solid battery electrodes, such as those disclosed in Patent Document 1, often result in degraded battery performance due to the surfaces of active materials and solid electrolytes being covered with binders, leading to increased ion and electron conduction resistance.

Innovation Solution

A method involving the use of a slurry-form electrode composition made with a good solvent and a poor solvent for the binder, allowing the binder to be deposited in a point-like or linear manner between active materials and solid electrolytes, thereby reducing conduction resistance and improving battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the surfaces of active materials and solid electrolytes are covered with binders to ensure structural integrity, then the structural stability is improved, but the ion and electron conduction resistance increases leading to degraded battery performance

Engineering Contradiction:

Improvestructural stabilityVSAvoidbattery performance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The binder is applied selectively only at the contact points between particles rather than uniformly covering all surfaces. This localized application maintains structural integrity at interfaces while preserving conduction pathways on particle surfaces, resolving the contradiction between structural stability and battery performance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The binder concentration and coverage are controlled to be partial rather than complete. By using a limited amount of binder that only bridges particle contacts, the structure gains sufficient mechanical stability without excessive binder coverage that would block conduction pathways and degrade performance

Inventive Principle:

Principle #16Partial or excessive action

2Stability of the object's composition

If a uniform binder coating is applied to ensure complete coverage and structural integrity, then the structural stability is improved, but the conduction resistance increases leading to lower discharge/charge capacity

Engineering Contradiction:

Improvestructural stabilityVSAvoiddischarge/charge capacity

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The binder distribution is made non-uniform and localized to contact regions between particles. This selective localization ensures structural stability is achieved only where mechanically needed, while maintaining high conduction capacity on particle surfaces where electrochemical reactions occur

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

A slurry formulation with specific solvent composition is used to control binder deposition. The slurry allows binder to flow and settle naturally into contact points during application and drying, creating a localized distribution pattern that optimizes both structural and functional properties

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Strength

If excessive binder is used to ensure complete particle bonding, then the structural integrity is improved, but the ion and electron conduction pathways are blocked leading to increased conduction resistance

Engineering Contradiction:

Improvestructural integrityVSAvoidconduction efficiency

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The binder amount is precisely controlled to be just sufficient for particle bonding without excess. This partial action approach provides adequate structural integrity for electrode handling while preventing binder over-coverage that would block conduction pathways and reduce efficiency

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The binder properties and concentration parameters are optimized to achieve maximum bonding efficiency at minimum coverage. By adjusting binder molecular weight, functional groups, and concentration in the slurry, the system achieves structural integrity with minimal binder usage, preserving conduction efficiency

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 enhances the performance of solid batteries by reducing ion and electron conduction resistance, leading to improved discharge/charge capacity and output compared to conventional techniques.

Implementation Method 1

the solvent includes a good solvent for the binder and a poor solvent for the binder

Methodology Applied

Scientific EffectSolubility: Solvation

Implementation Method 2

the binder to be deposited in a point-like or linear manner between active materials and solid electrolytes

Methodology Applied

Scientific EffectPhase separation: Phase Change

Implementation Method 3

drying the slurry-form electrode composition that has been applied

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS8951600B2Method for producing electrode for solid battery

Publication Date: 2015.02.10 TOYOTA JIDOSHA KK

AI summary

The present invention provides a method for producing an electrode for a solid battery which can improve battery performance. The method for producing an electrode for a solid battery comprises the steps of: mixing an active material, a solid electrolyte, a binder, and a solvent to make a slurry-form electrode composition; applying the slurry-form electrode composition made; and drying the slurry-form electrode composition applied, wherein the solvent includes a good solvent for the binder and a poor solvent for the binder.