Separator Coating Adhesion Gradient for Lithium Plating Control

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Solution Overview

Problem

Conventional batteries, such as lithium ion batteries, face limitations in energy density and cyclability due to lithium plating, which can lead to electrical disconnection and reduced capacity, especially when lithium plates between the anode and separator, rather than between the anode current collector and coating layer.

Innovation Solution

A battery cell design where the adhesion between the separator coating layer and the anode coating layer is stronger than the adhesion between the anode coating layer and the anode current collector, encouraging lithium plating to occur between the anode current collector and the anode coating layer, thus maintaining electrical connection and improving cyclability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium is plated on the anode as lithium metal to increase capacity, then the anode capacity increases, but the cyclability of the battery cell deteriorates due to lithium being electrically disconnected from other components

Engineering Contradiction:

Improveanode capacityVSAvoidcyclability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A separator coating layer is introduced as an intermediary between the separator and anode coating layer. This coating layer has specific adhesion properties that encourage lithium plating to occur within the anode coating layer rather than at the separator interface, maintaining electrical connection while allowing high capacity operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesion strength parameters of different interfaces are deliberately modified. The separator coating layer is designed with adhesion strength to the anode coating layer greater than the adhesion strength of the anode coating layer to the current collector, creating controlled plating behavior that improves cyclability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the adhesion between anode coating layer and current collector is strong to maintain electrical connection, then cyclability improves, but lithium plating may occur at the separator interface causing electrical disconnection

Engineering Contradiction:

ImprovecyclabilityVSAvoidlithium plating at separator interface

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The separator coating layer acts as a mediator that redirects lithium plating away from the harmful separator interface. By controlling the adhesion strength gradient, the coating layer guides lithium deposition into the anode coating layer where it remains electrically connected

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Different regions of the anode structure are given different adhesion properties. The separator coating layer has locally optimized adhesion strength relative to the anode coating layer, creating a spatial gradient that controls where lithium plating occurs, preventing it at the separator interface while allowing it in the anode coating layer

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 design enhances ion storage capacity and reduces the degradation of battery performance by ensuring lithium remains electrically connected, leading to better energy density and longer cycle life.

Implementation Method 1

A second bond between the separator coating layer and the anode coating layer may have a second adhesion strength. The second adhesion strength of the second bond may be greater than the first adhesion strength of the first bond

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11462804B2Systems and methods to control lithium plating

Publication Date: 2022.10.04 TERAWATT TECHNOLOGY INC

AI summary

Various battery cell arrangements are presented herein. The battery cell can include an anode current collector. The battery cell can include a carbon-based anode coating layer that coats the anode current collector. A first bond between the anode current collector and the anode coating layer may have a first adhesion strength. The battery cell also includes a cathode, a separator layer that contacts the cathode, and a separator coating layer. The separator coating layer can be positioned between the anode coating layer and the separator layer. A second bond between the separator coating material and the anode coating material has a second adhesion strength. The second adhesion strength of the second bond may be greater than the first adhesion strength of the first bond.