Coated Current Collector for SEI Stress Relief in Lithium-Ion Cells

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing lithium-ion batteries face challenges in reducing interfacial stress on the solid electrolyte interphase (SEI) layer during cycling, which can lead to damage and the formation of lithium dendrites, affecting performance and cycle life.

Innovation Solution

Incorporating a deformable layer with a polymeric material on the surface of the current collector in the lithium metal anode, which is lithium-ion conductive and has a Young's modulus less than that of the SEI layer, to mitigate interfacial stress and promote mechanical stretchability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid current collector is used, then structural stability is maintained, but interfacial stress on the SEI layer increases during cycling

Engineering Contradiction:

Improvestructural stability of current collectorVSAvoidinterfacial stress on SEI layer

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

A deformable layer with polymeric material is applied on the surface of the current collector. This layer has a Young's modulus less than that of the SEI layer, allowing it to deform and accommodate volume changes during lithium plating and stripping cycles, thereby reducing interfacial stress on the SEI layer while maintaining overall structural stability.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The current collector is designed as a composite structure consisting of a rigid substrate providing structural stability and a deformable polymeric layer providing stress relief. This composite architecture combines the advantages of both rigid and flexible materials to simultaneously maintain structural integrity and reduce harmful interfacial stress.

Inventive Principle:

Principle #40Composite materials

2Strength

If the SEI layer is made more rigid to protect against damage, then mechanical strength increases, but stress accumulation during cycling worsens

Engineering Contradiction:

Improvemechanical strength of SEI layerVSAvoidstress accumulation during cycling

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The deformable polymeric layer acts as an intermediary between the rigid current collector and the SEI layer. It serves as a stress buffer that absorbs and dissipates mechanical stress during cycling, protecting the rigid SEI layer from stress accumulation while allowing the layer to maintain its mechanical strength and protective function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If lithium metal is plated directly on the current collector, then capacity is maximized, but dendrite formation increases due to SEI layer damage

Engineering Contradiction:

Improvelithium metal capacityVSAvoiddendrite formation resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The deformable polymeric layer is applied to the current collector surface before lithium metal plating occurs. This preliminary action creates a protective interface that prevents SEI layer damage during subsequent lithium plating and stripping cycles, thereby preventing dendrite formation while allowing maximum lithium capacity to be achieved.

Inventive Principle:

Principle #10Preliminary action

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 deformable layer effectively reduces interfacial stress on the SEI layer, thereby protecting it from damage, reducing the likelihood of lithium dendrite formation, and enhancing the cycle life and performance of the lithium-ion cell.

Implementation Method 1

The deformable layer is configured to reduce interfacial stress acting upon the SEI layer during cycling of the lithium-ion cell. The deformable layer of the lithium-ion cell has a Young's modulus that is less than a Young's modulus of the SEI layer that forms during charge of the lithium-ion cell.

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The deformable layer is lithium-ion conductive and includes a polymeric material.

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS20250062362A1Lithium-ion cells including a coated current collector and methods of forming the same

Publication Date: 2025.02.20 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

Lithium-ion cells and methods for producing such cells are provided. The lithium-ion cells include a lithium metal anode (LMA), a cathode, and an electrolyte between the LMA and the cathode. The LMA includes a current collector and a deformable layer on a surface of the current collector. The deformable layer is lithium-ion conductive and includes a polymeric material. The cathode has a lithium intercalation material. In some examples, lithium metal is plated on the deformable layer during charge of the lithium-ion cell to define a plated lithium layer between the deformable layer and the electrolyte, and a solid electrolyte interphase (SEI) layer forms on the plated lithium layer separating the plated lithium layer from the electrolyte.