Solid Electrolyte Battery Segmented Layer Design

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Solution Overview

Problem

All-solid-state lithium batteries lack sufficient high output power and capacity due to inadequate ion conductivity and internal resistance issues in existing solid electrolyte configurations.

Innovation Solution

A solid electrolyte battery design featuring a first solid electrolyte layer without nitrogen, in contact with a positive electrode, and a second solid electrolyte layer containing oxynitride, in contact with a negative electrode, utilizing alkali or alkaline earth metals to enhance ion conductivity and reduce internal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional solid electrolyte configuration is used, then the battery structure is simple, but the ion conductivity is insufficient and internal resistance is high

Engineering Contradiction:
Improveion conductivityVSAvoidelectrolyte layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solid electrolyte is divided into multiple layers with different compositions: a first solid electrolyte layer containing Li2SiO3 and a second solid electrolyte layer containing Li3PO4. Each layer serves specific functions to optimize ion conductivity at different interfaces while maintaining overall structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the solid electrolyte are assigned different material compositions tailored to local requirements. The first layer contacts the positive electrode with specific interface compatibility needs, while the second layer contacts the negative electrode with different electrochemical stability requirements, optimizing performance locally at each interface.

Inventive Principle:
Principle #3Local quality

2Reliability

If the solid electrolyte layer is made thicker to improve safety, then safety increases, but internal resistance increases and output power decreases

Engineering Contradiction:
ImprovesafetyVSAvoidoutput power
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The solid electrolyte uses a composite structure combining Li2SiO3 and Li3PO4 materials in distinct layers. This composite approach achieves high ion conductivity comparable to liquid electrolytes while maintaining the physical safety advantages of solid electrolytes, allowing adequate thickness without excessive internal resistance.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a single-layer solid electrolyte is used, then manufacturing is simple, but interface resistance with electrodes is high

Engineering Contradiction:
Improveinterface ion conductivityVSAvoidelectrolyte fabrication
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The electrolyte is segmented into two functional layers that can be sequentially deposited using standard sputtering equipment. The first layer is formed at lower power (50-100W) and the second at higher power (100-200W), utilizing conventional manufacturing processes to achieve superior interface properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention controls specific deposition parameters including radio frequency power (50-200W range), oxygen partial pressure (0.1-10 Pa), and layer thickness to optimize interface resistance. These parameter adjustments enable low interface resistance while using standard manufacturing equipment.

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

The configuration significantly increases first metal ion conductivity, decreases internal resistance, and achieves high-power and high-capacity performance in lithium secondary batteries.

Implementation Method 1

the first metal ion conductivity is increased at the interface between the first solid electrolyte layer and the positive electrode and at the interface between the second solid electrolyte layer and the negative electrode, and therefore, the internal resistance is decreased

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP3093913B1Solid electrolyte battery, electrode assembly, composite solid electrolyte, and method for producing solid electrolyte battery
Publication Date: 2019.09.04 SEIKO EPSON CORP
  • EP3093913B1 patent drawingFigure 1~2
  • EP3093913B1 patent drawingFigure 3
  • EP3093913B1 patent drawingFigure 4A~4B

AI summary

A lithium secondary battery (solid electrolyte battery) includes a positive electrode which includes a positive electrode active material layer containing lithium oxide, a negative electrode which includes a negative electrode active material layer, a first solid electrolyte layer which is provided in contact with the positive electrode active material layer between the positive electrode and the negative electrode and contains lithium and oxygen, and a second solid electrolyte layer which is provided in contact with the negative electrode active material layer between the positive electrode and the negative electrode and contains lithium, nitrogen, and oxygen. It is preferred that each of the first solid electrolyte layer and the second solid electrolyte layer further contains boron.