Anode Buffering Zone for Lithium Ion Safety

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Solution Overview

Problem

Lithium ion batteries face safety risks due to thermal runaway, cell breakdown, and the potential for fire or explosion, particularly when overheated or overcharged, and are prone to lithium metallization and dendrite growth, which can lead to battery failure.

Innovation Solution

The development of an anode with a buffering zone that partially masks the positive charge of lithium ions, allowing them to move into the anode material for lithiation, using electron donating groups interspaced with non-electron donating groups at a specific ratio to prevent lithium ion accumulation and dendrite growth, thereby enhancing safety and enabling fast charging rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lithium ion batteries use conventional anode materials, then they achieve basic energy storage function, but they are prone to lithium metallization and dendrite growth causing safety risks

Engineering Contradiction:

ImprovesafetyVSAvoidlithium metallization and dendrite growth

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a buffering zone comprising electron-donating groups as an intermediary layer between the electrolyte and the anode active material particles. This buffering zone mediates the interaction by partially masking the positive charge of lithium ions, preventing direct contact and subsequent metallization/dendrite formation on the anode surface, thus resolving the safety issue.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the surface charge characteristics of the anode by introducing electron-donating groups with specific ratios (at least 1:2 ratio of electron-donating to non-electron-donating groups). This parameter change in the buffering zone creates a controlled electrostatic environment that prevents lithium ion accumulation and metallization, thereby improving safety.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If lithium ion batteries are charged at high rates, then charging speed is improved, but thermal runaway and cell breakdown risks increase

Engineering Contradiction:

Improvecharging rateVSAvoidthermal stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The buffering zone with electron-donating groups serves as a pre-established protective cushion between the electrolyte and anode material. During high-rate charging, this buffering zone absorbs and moderates the intense lithium ion flux before it reaches the anode active material, preventing thermal runaway and cell breakdown while enabling fast charging.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the buffering zone has high electron donating group density, then lithium ion masking is improved, but lithium ion movement into anode material is hindered

Engineering Contradiction:

Improvelithium ion maskingVSAvoidlithium ion movement speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent optimizes the buffering zone composition by specifying a minimum ratio of electron-donating to non-electron-donating groups (at least 1:2). This parameter optimization ensures sufficient lithium ion masking capability while maintaining adequate ion transport pathways, balancing safety and charging performance.

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 solution significantly reduces the probability of lithium metallization and dendrite growth, enhancing the safety and performance of lithium ion batteries by allowing for high charging and discharging rates while maintaining mechanical stability and preventing thermal runaway.

Implementation Method 1

the buffering zone comprises a plurality of electron donating groups interspaced between non-electron donating groups at a ratio of at least 1:2

Methodology Applied

Scientific EffectElectron donation: Redox Reactions

Data Source

PatentUS10367193B2Methods of preparing anodes using tin as active material

Publication Date: 2019.07.30 STOREDOT

AI summary

Improved anodes and cells are provided, which enable fast charging rates with enhanced safety due to much reduced probability of metallization of lithium on the anode, preventing dendrite growth and related risks of fire or explosion. Anodes and/or electrolytes have buffering zones for partly reducing and gradually introducing lithium ions into the anode for lithiation, to prevent lithium ion accumulation at the anode electrolyte interface and consequent metallization and dendrite growth. Various anode active materials and combinations, modifications through nanoparticles and a range of coatings which implement the improved anodes are provided.