Solid State Battery Electrolyte Contact via Buffer Layer

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Solution Overview

Problem

Conventional lithium batteries using organic electrolytes face issues with reliability due to leakage, ignition, and limited operating temperature ranges, and existing solid-state batteries struggle with achieving ideal electrical contact between electrodes and solid electrolytes, leading to reduced performance and complexity in manufacturing.

Innovation Solution

A solid-state battery design where a thin layer of lithium ion conductive solid electrolyte, preferably with lithium ion conductive glass ceramics, is interposed between positive and negative electrodes, with metal oxides like Co, Ni, Mn, Nb, and Si-based compounds used for the electrodes, ensuring high lithium ion conductivity and preventing unfavorable reactions during the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid electrolyte is used instead of organic electrolyte solution, then reliability is improved by preventing leakage and ignition, but electrical contact between electrode layers and solid electrolyte layer becomes inadequate

Engineering Contradiction:
Improvebattery reliabilityVSAvoidelectrical contact quality
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

A buffer layer is introduced as an intermediary between the solid electrolyte layer and electrode layers. This buffer layer facilitates adequate electrical contact while maintaining the reliability benefits of solid electrolyte, resolving the contradiction between reliability improvement and manufacturing difficulty.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes physical parameters of the solid electrolyte layer (thickness, density, composition) to optimize electrical contact. By adjusting these parameters, the solid electrolyte maintains its reliability advantages while achieving sufficient electrical conductivity for manufacturing.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If pressure molding is used to join positive electrode, solid electrolyte, and negative electrode, then assembly is achieved, but electrical contact of solid electrolyte layer and electrode layers remains inadequate leading to capacity degradation

Engineering Contradiction:
Improveassembly capabilityVSAvoidcapacity stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The buffer layer serves as a mediator that enables effective electrical contact between the solid electrolyte and electrodes under pressure molding conditions. This intermediary ensures that assembly is achieved while preventing capacity degradation, resolving the contradiction between ease of manufacture and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If mixture of active material powder and solid electrolyte powder is used as electrode, then service rate of active material is improved by reducing impedance, but manufacturing complexity increases

Engineering Contradiction:
Improveservice rateVSAvoidmanufacturing process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention merges the electrode and solid electrolyte into a single integrated layer structure. This combining approach maintains the high service rate benefits of mixed powder electrodes while simplifying the manufacturing process by reducing the number of separate components and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enhances the reliability and performance of the battery by maintaining high lithium ion conductivity, preventing electrode degradation, and simplifying the manufacturing process while ensuring stable ion conduction and chemical stability, thus improving the battery's overall efficiency and capacity.

Implementation Method 1

a solid electrolyte having a lithium ion conductive property instead of the organic electrolyte solution

Methodology Applied
Scientific EffectLithium ion conduction: Conduction (electrical)

Data Source

PatentEP2086038B1Solid State Battery
Publication Date: 2013.11.20 OHARA INC
  • EP2086038B1 patent drawingFigure 1~2
  • EP2086038B1 patent drawingFigure 3
  • EP2086038B1 patent drawingFigure 4

AI summary

A solid state battery comprising: a solid electrolyte; a positive electrode containing an active material; and a negative electrode containing an active material is provided. The solid electrolyte is disposed between the positive electrode and the negative electrode. At least one of the positive electrode active material and the negative electrode active material contains a metal oxide.