Folding Lithium-Air Battery Separator for Electrolyte Retention

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Solution Overview

Problem

Lithium air batteries face challenges with electrolyte volatilization, durability deterioration, and complex manufacturing processes, particularly in pouch and stack types, which affect stability and safety.

Innovation Solution

A folding type lithium air battery design featuring a multi-layered separator with a first electrolyte membrane, a diffusion prevention membrane, and a second electrolyte membrane, containing ionic liquids and polymers, is used to surround the edges of positive and negative electrode composites, forming a zigzag shape to enhance stability and prevent short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a pouch type battery structure with oxygen inlet hole is used, then air supply to electrode is enabled, but electrolyte leaks or volatilizes out of the hole and compression molding is difficult

Engineering Contradiction:

Improveair supply structureVSAvoidelectrolyte retention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The separator is divided into multiple layers including hydrophobic layers at the edges and a hydrophilic core layer, creating segmented functional zones that prevent electrolyte leakage while maintaining air supply pathways

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separator uses a thin film structure with hydrophobic edge layers that form a barrier against electrolyte leakage, while the overall flexible design allows for compression molding without requiring rigid holes in the pouch

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of manufacture

If a stack type battery structure is used, then manufacturing of prismatic battery is simplified, but electrode is pushed when shocks are applied causing short circuit

Engineering Contradiction:

Improveprismatic battery manufacturingVSAvoidelectrode stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The separator is designed with extended edge portions that protrude beyond the electrode edges, creating a cushioning barrier that prevents electrode-to-electrode contact during shocks or expansion, thereby avoiding short circuits while maintaining the compact stack structure

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If non-volatile electrolyte is used, then electrolyte volatilization is prevented, but electrolyte is decomposed by chemical reaction with lithium negative electrode or high voltage of positive electrode

Engineering Contradiction:

Improveelectrolyte stabilityVSAvoidelectrolyte decomposition

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The separator employs different electrolyte compositions in different zones: hydrophobic layers with non-volatile electrolytes at the edges for volatility prevention, and a hydrophilic core layer with volatile electrolyte for high ionic conductivity, with each zone optimized for its specific function

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separator is constructed as a composite of multiple layers with different properties (hydrophobic/non-volatile and hydrophilic/volatile electrolytes), combining the advantages of both electrolyte types while mitigating their individual disadvantages through spatial separation

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If single layer electrolyte membrane is used, then manufacturing is simplified, but it is difficult to maintain excellent rigidity at both positive and negative electrodes due to side reactions

Engineering Contradiction:

Improveseparator manufacturingVSAvoidelectrode rigidity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The separator is segmented into multiple functional layers including hydrophobic layers with reinforcing fibers for mechanical strength at the edges, and a hydrophilic core layer for ionic conductivity, with each layer contributing specific properties to maintain overall structural integrity

Inventive Principle:

Principle #1Segmentation

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 design improves electrode stability, prevents electrolyte volatilization, and increases battery capacity and life by enhancing energy density and ionic conductivity, while simplifying the manufacturing process and reducing the risk of explosions or fires.

Implementation Method 1

a first electrolyte membrane, a diffusion prevention membrane, and a second electrolyte membrane, which contain a non-volatile electrolyte and ionic liquids

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

a diffusion prevention membrane that is positioned between the first electrolyte membrane and the second electrolyte membrane

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS20250007046A1Folding type lithium air battery and method for manufacturing same

Publication Date: 2025.01.02 KIA CORPORATION

AI summary

Disclosed herein are a folding type lithium air battery and a method for manufacturing the battery. The lithium air battery is configured such that a first electrolyte membrane and a second electrolyte membrane including reinforcing layers and ionic liquids that are suitable for a positive electrode and a negative electrode, respectively, are formed, and a separator including a diffusion prevention membrane is provided between the first electrolyte membrane and the second electrolyte membrane, thus guaranteeing the stability of an electrode, and improving battery performance due to excellent ionic conductivity.