Porous Solid-State Battery Electrolyte for Adhesion and Ion Conduction

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Solution Overview

Problem

Current solid-state batteries face challenges with ion conductivity and durability due to the use of organic solid electrolytes and high grain boundary resistivities in oxide solid electrolytes, leading to performance drops and detachment issues at the interface between electrode layers.

Innovation Solution

Incorporating a porous solid electrolyte with a fibrous structure in at least one of the electrode layers to relieve stress caused by expansion and contraction, and to maintain ion conduction pathways, while using a combination of solid electrolyte particles with varying diameters to enhance adhesion and dispersibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a binder is added to increase adhesion strength between powders and layers, then adhesion improves, but ion conductivity decreases causing performance drop

Engineering Contradiction:

Improveadhesion strengthVSAvoidion conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent employs a porous solid electrolyte layer that contains voids or pores within its structure. This porous structure allows ion conduction pathways to be maintained even when binder is present, as the pores provide channels for ion transport. The binder fills the spaces between particles and provides adhesion, while the porous structure ensures ion conductivity is not completely blocked, resolving the contradiction between adhesion strength and ion conductivity.

Inventive Principle:

Principle #31Porous materials

2Reliability

If the thickness of solid-state battery is reduced to decrease grain boundary resistivity, then ion conductivity improves, but battery capacity decreases

Engineering Contradiction:

Improveion conductivityVSAvoidbattery capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies local quality by creating a porous structure specifically in the solid electrolyte layer, concentrating the ion conduction pathways in this specific region. This allows the electrolyte layer to maintain high ion conductivity locally through the porous channels, while the overall battery can be designed with sufficient capacity by optimizing the electrode active material content elsewhere in the structure.

Inventive Principle:

Principle #3Local quality

3Reliability

If sintering is used to decrease grain boundary resistivity of oxide solid electrolyte, then ion conductivity improves, but constituent elements interdiffuse causing deterioration

Engineering Contradiction:

Improveion conductivityVSAvoidconstituent element distribution

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the physical and chemical parameters of the solid electrolyte by creating a porous structure through controlled processes rather than high-temperature sintering. This parameter change allows achieving low grain boundary resistivity and high ion conductivity through the porous architecture without subjecting the battery constituents to temperatures that would cause element interdiffusion and composition deterioration.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If a small amount of binder is used to maintain ion conductivity, then ion conductivity is preserved, but detachment occurs at interface due to expansion and contraction

Engineering Contradiction:

Improveion conductivityVSAvoidadhesion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The porous solid electrolyte layer acts as a buffer that can accommodate expansion and contraction of electrode materials during charge-discharge cycles. The voids and pores in the porous structure provide space for volume changes, reducing mechanical stress at the interfaces. This allows sufficient binder to be present for strong adhesion without completely blocking ion conduction pathways, as the porous structure maintains ion transport channels.

Inventive Principle:

Principle #31Porous materials

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 porous solid electrolyte structure improves battery performance by reducing deterioration and maintaining ion conductivity, allowing for increased battery capacity and reliability.

Implementation Method 1

at least one of the first solid electrolyte and the second solid electrolyte containing a porous solid electrolyte

Methodology Applied

Scientific EffectStress relief through porous structure: Porosity

Implementation Method 2

a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer and containing a solid electrolyte and a binder

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS11923510B2Solid-state battery and method of manufacture thereof

Publication Date: 2024.03.05 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A solid-state battery that exhibits improved battery performance includes: a positive-electrode collector; a negative-electrode collector; a positive electrode layer formed on the positive-electrode collector and containing a positive-electrode active material and a solid electrolyte; a negative electrode layer formed on the negative-electrode collector and containing a negative-electrode active material and a solid electrolyte; and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer and containing a solid electrolyte. At least one of the solid electrolyte and the solid electrolyte partly represents a porous solid electrolyte.