Solid-State Battery Electrode Assembly With Crosslinked Interface Binder

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Solution Overview

Problem

Solid state batteries face challenges with low ion conductivity due to poor interfacial contact between electrode and electrolyte layers, leading to decreased performance.

Innovation Solution

A method for manufacturing a solid state battery involving the use of a crosslinking agent to form a continuous phase at the interfaces between the electrodes and the solid polymer electrolyte layer, utilizing a rubber-based binder resin and a nonpolar solvent to enhance interfacial binding force and maintain high ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid electrolyte is used instead of an electrolyte solution, then stability and energy density are improved, but ion conductivity decreases due to low interfacial contact with the electrode

Engineering Contradiction:
ImprovestabilityVSAvoidion conductivity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A binder layer is introduced as an intermediary substance between the solid electrolyte and the electrode. This binder layer has dual functionality: it provides adhesive force to ensure good interfacial contact, and simultaneously possesses ion conductivity to maintain efficient ion transport. The binder layer composition includes solid electrolyte particles (30-70 wt%), binder resin (5-40 wt%), and conductive particles (5-40 wt%), creating a composite structure that mediates between the solid electrolyte and electrode interfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If a solid electrolyte is used instead of an electrolyte solution, then energy density is improved, but interfacial contact with the electrode is poor

Engineering Contradiction:
Improveenergy densityVSAvoidinterfacial contact
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The binder layer is designed as a composite material combining solid electrolyte particles, binder resin, and conductive particles in specific proportions. This composite structure provides both mechanical adhesion through the binder resin and electrical/ionical conductivity through the conductive particles and solid electrolyte, while maintaining good interfacial contact with both the solid electrolyte and electrode surfaces.

Inventive Principle:
Principle #40Composite 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 method results in improved ion conductivity and battery performance by increasing the binding force between the electrodes and electrolyte layers, leading to enhanced adhesion and cycle characteristics.

Implementation Method 1

the binder polymer resin of the electrode assembly (a') is crosslinked to form an interlayer continuous phase at the interface between the negative electrode and the solid electrolyte layer and at the interface between the positive electrode and the solid electrolyte layer

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

warming the impregnated electrode assembly (a) to form an electrode assembly (a'), wherein the positive electrode, the negative electrode and the solid electrolyte layer comprise a binder polymer resin, and the binder polymer resin of the electrode assembly (a') is crosslinked

Methodology Applied
Scientific EffectThermal activation: Heating

Data Source

PatentEP3570358B1Electrode assembly for solid state battery and method for manufacturing the same
Publication Date: 2024.11.20 LG ENERGY SOLUTION LTD
  • EP3570358B1 patent drawingFigure 1~2

AI summary

The present disclosure relates to an electrode assembly for a solid state battery. The electrode assembly includes a positive electrode, a negative electrode and a solid electrolyte layer interposed between the positive electrode and the negative electrode. In addition, the binder disposed at the interface between the negative electrode and the solid electrolyte layer, the interface between the positive electrode and the solid electrolyte layer and/or at a predetermined depth from the interface is crosslinked to form a three-dimensional network. In other words, in the electrode assembly, the binder contained in the negative electrode and the solid electrolyte layer and/or the binder contained in the positive electrode and the solid electrolyte layer is crosslinked to improve the interfacial binding force between the negative electrode and the solid electrolyte layer and/or between the positive electrode and the solid electrolyte layer, and thus ion conductivity is maintained to a significantly high level.