Lithium-ion Conductive Sulfide Solid Electrolyte Battery

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Solution Overview

Problem

Lithium-ion secondary batteries face safety concerns when scaled for large-sized applications due to the risk of liquid leakage and gas generation from non-aqueous electrolyte solutions, which complicates their use in large-scale devices like hybrid cars and power storage systems.

Innovation Solution

A lithium-ion conductive sulfide solid electrolyte battery design incorporating elements such as Al, Si, Fe, Ni, and Zr within specific content ranges in the lithium-ion conductive sulfide, enhancing lithium ion conductivity and safety through improved electrolyte layer composition and electrode structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-aqueous electrolyte solution is used in lithium-ion secondary battery, then electrochemical performance is achieved, but safety deteriorates due to liquid leakage and gas generation risks

Engineering Contradiction:

ImprovesafetyVSAvoidliquid leakage and gas generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the electrolyte from liquid (non-aqueous electrolyte solution) to solid (lithium-ion conductive sulfide). This fundamental parameter change eliminates the harmful effects of liquid leakage and gas generation while maintaining lithium ion conductivity through solid-state ion transport mechanisms

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention utilizes the phase transition from liquid electrolyte to solid electrolyte. The lithium-ion conductive sulfide operates as a solid electrolyte that conducts lithium ions through its crystal structure, fundamentally changing the phase state to eliminate safety issues associated with liquid electrolytes

Inventive Principle:

Principle #36Phase transitions

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 battery design achieves increased lithium ion conductivity and safety, enabling effective use in large-scale applications by maintaining high energy density and reducing internal resistance, thus addressing the safety concerns associated with traditional lithium-ion batteries.

Implementation Method 1

a solid electrolyte layer, wherein the solid electrolyte layer includes at least one selected from a group consisting of Al, Si, Fe, Ni, and Zr, the total content of the element in the lithium-ion conductive sulfide being 0.03% by mass or more and 0.3% by mass or less

Methodology Applied

Scientific EffectLithium ion conduction: Conduction (electrical)

Data Source

PatentUS9929434B2Lithium-ion conductive sulfide, solid electrolyte secondary battery and battery pack

Publication Date: 2018.03.27 KK TOSHIBA

AI summary

According to one embodiment, a solid electrolyte secondary battery includes a positive electrode containing an active material, a negative electrode containing an active material, and a solid electrolyte layer. The solid electrolyte layer includes a lithium-ion conductive sulfide containing at least one element selected from a group consisting of Al, Si, Fe, Ni, and Zr, the total content of the element in the lithium-ion conductive sulfide is 0.03% by mass or more and 0.3% by mass or less.