Lithium Air Battery Humidity Control for Stability

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Solution Overview

Problem

Conventional lithium air batteries face issues with stability during charging and discharging due to overvoltage, leading to reduced capacity and performance, primarily because of the volatilization of organic electrolytic solutions, which increases battery resistance and deteriorates performance over time.

Innovation Solution

A lithium air battery system with a humidity control unit that adjusts the humidity of the gas contacting the positive electrode based on the battery's temperature, maintaining a lithium ion conductive layer and enabling stable charging and discharging by using a solid electrolyte layer between the negative and positive electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an organic electrolytic solution is used in the lithium air battery, then high ion conductivity is achieved, but the organic solvent volatilizes during long-term operation causing increased battery resistance and performance deterioration

Engineering Contradiction:

Improvelong-term operation stabilityVSAvoidelectrolyte volatilization

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the physical state parameter of the electrolyte from liquid (organic electrolytic solution) to solid (solid electrolyte layer), eliminating volatilization while maintaining ion conductivity through solid-state ion transport mechanisms

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the volatile organic electrolyte with a solid electrolyte material that does not evaporate, effectively creating a non-consumable electrolyte system for long-term stable operation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If the battery temperature rises to improve solid electrolyte ion conductivity, then ion conductivity increases, but electrolyte volatilization is accelerated

Engineering Contradiction:

Improveion conductivityVSAvoidelectrolyte volatilization

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the electrolyte from liquid to solid state, allowing ion conductivity improvement through temperature rise without the harmful side effect of volatilization that occurs in liquid organic electrolytes

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a humidity control unit is added to control gas humidity based on battery temperature, then stable charging and discharging is achieved, but device complexity increases

Engineering Contradiction:

Improvecharging and discharging stabilityVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The humidity control unit implements feedback control by sensing battery temperature and adjusting gas humidity accordingly, creating a closed-loop system that maintains optimal operating conditions for stable charge-discharge cycles

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts gas humidity based on real-time battery temperature conditions, adapting the operating environment to maintain performance stability across varying temperature ranges

Inventive Principle:

Principle #15Dynamics

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 system ensures stable charge and discharge within the operating temperature range by controlling humidity, preventing the volatilization of electrolytes and maintaining ion conductivity, thus enhancing the battery's performance and longevity.

Implementation Method 1

a solid electrolyte layer including a solid electrolyte interposed between the negative electrode and the positive electrode

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

a positive electrode made of a positive electrode material and including a catalyst for reducing oxygen which is positive electrode active material

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 3

Positive Electrode: 2Li++O2+2e−→Li2O2

Methodology Applied

Scientific EffectOxygen reduction reaction: Redox Reactions

Implementation Method 4

a negative electrode made of a negative electrode material for absorbing and releasing a lithium ion

Methodology Applied

Scientific EffectIon absorption and release: Absorption (physical)

Implementation Method 5

a humidity control unit (5, 7) that adjusts a humidity of gas which includes oxygen and contacts with at least the positive electrode. The humidity control unit adjusts the humidity of the gas based on a temperature of the lithium air battery

Methodology Applied

Scientific EffectHumidity control:

Data Source

PatentUS10879574B2Lithium air battery system

Publication Date: 2020.12.29 DENSO CORP

AI summary

A lithium air battery system includes: a lithium air battery that includes a negative electrode made of a negative electrode material for absorbing and releasing a lithium ion, a positive electrode made of a positive electrode material and including a catalyst for reducing oxygen which is positive electrode active material, and a solid electrolyte layer including a solid electrolyte interposed between the negative electrode and the positive electrode; and a humidity control unit that adjusts a humidity of gas which includes oxygen and contacts with at least the positive electrode. The humidity control unit adjusts the humidity of the gas based on a temperature of the lithium air battery at least during operation of the lithium air battery.