Multi-Layer Current Collector for Solid-State Battery Volume Change

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Solution Overview

Problem

Lithium-ion and silicon-based solid-state batteries face performance degradation due to large volume changes during charge and discharge, leading to stress fluctuations and strain accumulation, which requires high stack pressures to maintain interfacial contact.

Innovation Solution

A secondary solid-state battery design featuring a current collector with a metal foam enclosed between two microporous carbon layers, or an elastomer sandwiched between metal foil layers, allowing for elastic compensation of electrode expansion and contraction, reducing the need for high stack pressures and enhancing mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high stack pressure is applied to maintain interfacial contact, then contact stability is improved, but device complexity and mechanical stress increase

Engineering Contradiction:

Improveinterfacial contact stabilityVSAvoidstack pressure requirement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a flexible buffer layer comprising a porous polymer foam substrate coated with a flexible polymer layer. This flexible structure can deform elastically to accommodate volume changes in the electrode, maintaining interfacial contact without requiring high stack pressure, thus resolving the contradiction between contact stability and device complexity

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the mechanical parameters of the current collector system by introducing a buffer layer with specific elastic modulus and porosity. This allows the system to adapt to volume changes through elastic deformation rather than relying on high external pressure, reducing the stack pressure requirement while maintaining contact stability

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If metallic anodes are used to increase energy density, then volumetric energy density is improved, but volume change during charge-discharge increases

Engineering Contradiction:

Improvevolumetric energy densityVSAvoidelectrode volume change

Core Design Contradiction:

Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The patent introduces a buffer layer between the metallic anode and current collector that anticipates and accommodates the volume expansion during charging. The porous foam structure provides pre-configured void space that absorbs the anode's volume increase, preventing stress accumulation and maintaining structural integrity throughout charge-discharge cycles

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent creates a composite current collector structure combining a porous polymer foam substrate with a flexible polymer coating layer. This composite material provides both the mechanical compliance needed to accommodate volume changes and the electrical conductivity required for current collection, enabling the use of high-capacity metallic anodes

Inventive Principle:

Principle #40Composite materials

3Reliability

If stack pressure is increased to prevent performance degradation, then cycle stability is improved, but manufacturing complexity and operational stress increase

Engineering Contradiction:

Improvecycle stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The buffer layer acts as a self-regulating component that automatically accommodates electrode volume changes through its elastic deformation. The porous structure expands and contracts with the electrode, maintaining optimal interfacial contact throughout cycling without requiring external pressure control mechanisms, thereby improving cycle stability while simplifying manufacturing

Inventive Principle:

Principle #25Self-service

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 mitigates stress fluctuations, improves cycle stability, and extends battery life by reducing operating stack pressure, while maintaining high energy density and simplifying battery packaging.

Implementation Method 1

The microporous carbon layers, which may consist of nano-sized carbon particles, can be coated on the metal foam

Methodology Applied

Scientific EffectCoating: Coatings

Implementation Method 2

This structure enables the current collector to compress or expand in response to the expansion or contraction of the positive and negative electrodes during charging and discharging, respectively

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20250006948A1Lithium-ion battery component with multi-layer electrode

Publication Date: 2025.01.02 FORD GLOBAL TECH LLC

AI summary

The present disclosure relates to a secondary solid-state battery, with a current collector configuration that includes a metal foam sandwiched between two microporous carbon layers. The current collector directly interfaces with both the negative electrode and the solid electrolyte separator. Alternatively, the current collector can comprise an elastomer sandwiched between a pair of metal foil layers, enabling responsive expansion and contraction in accordance with the electrodes' changes during charge-discharge cycles. Another embodiment contemplates a carbon fiber paper current collector situated between two microporous layers.