Current Collector Safety Layer for Lithium Plating and Short-Circuit Risk

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Solution Overview

Problem

Lithium ion batteries face issues with short circuits and lithium plating, leading to thermal runaway, due to the need for flexible electrodes that can prevent mechanical failures and maintain electrical contact during expansion, which existing designs struggle to address effectively.

Innovation Solution

The development of electrodes with a carbonized polymer that forms a self-supporting film with porosity and an electrode attachment substance like polyamideimide or polyvinylidene fluoride, which adheres to a current collector and allows for expansion without failure, and a safety layer to reduce exposure of the current collector to lithium deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If electrodes are made flexible to prevent mechanical failures during expansion, then mechanical integrity is improved, but electrical contact and structural stability deteriorate

Engineering Contradiction:

Improvemechanical integrityVSAvoidelectrical contact stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The electrode uses a composite structure combining a flexible polymer matrix (providing mechanical integrity and expansion accommodation) with conductive carbon materials (maintaining electrical contact). This composite approach allows the electrode to simultaneously achieve flexibility for mechanical stability and electrical conductivity for reliable contact during expansion and contraction cycles.

Inventive Principle:

Principle #40Composite materials

2Productivity

If current collector is exposed to lithium deposition to maintain electrochemical activity, then electrochemical performance is improved, but short circuits and thermal runaway risk increase

Engineering Contradiction:

Improveelectrochemical activityVSAvoidshort circuit risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary protective layer between the current collector and the lithium deposition environment. This layer allows lithium ions to deposit on the electrode material while preventing direct exposure of the current collector to lithium plating, thereby maintaining electrochemical activity without the harmful short circuits and thermal runaway risks associated with uncontrolled lithium deposition on the current collector.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If electrode film is made dense to improve electrical conductivity, then electrical contact is improved, but expansion accommodation and mechanical flexibility deteriorate

Engineering Contradiction:

Improveelectrical contactVSAvoidexpansion accommodation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The electrode structure employs local quality differentiation where different regions have different densities and properties. The polymer matrix provides a flexible, expandable structure in certain regions, while conductive carbon phases are distributed to ensure electrical connectivity. This localized variation in density and composition allows the electrode to simultaneously accommodate expansion mechanically while maintaining electrical conductivity through the conductive network.

Inventive Principle:

Principle #3Local quality

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

This solution enhances the mechanical integrity and cycle life of lithium ion batteries by preventing short circuits and lithium plating, allowing for higher energy density and reduced irreversible capacity, while maintaining electrical contact and structural integrity during expansion.

Implementation Method 1

an electrode attachment substance that adheres the film to the current collector

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

a carbon phase that holds the film together

Methodology Applied

Scientific EffectCohesion: Cohesion

Implementation Method 3

The film may include porosity and at least some of the electrode attachment substance may be within the porosity of the film

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS11784298B2Methods of reducing occurrences of short circuits and/or lithium plating in batteries

Publication Date: 2023.10.10 ENEVATE CORP

AI summary

An example method of reducing short circuits from occurring in a battery can include providing a current collector coated with a safety layer. The method can include providing an electrochemically active material film on the safety layer such that the safety layer is configured to reduce exposure of the current collector to an opposing electrode. The method can also include adhering the electrochemically active material film to the current collector via the safety layer.