Porous Buffer Layer for Anode-Free Solid-State Battery Swelling

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Solution Overview

Problem

Anode-free solid-state battery cells experience significant swelling during charging due to lithium ion plating on the anode current collector, leading to potential degradation and performance issues, especially in jelly-roll style batteries where repeated layers exacerbate swelling.

Innovation Solution

A porous lithium ion buffer layer is introduced between the anode current collector and the solid-state electrolyte, which is electrically conductive, flexible, and sufficiently porous to accommodate lithium ions, reducing swelling by storing ions within its voids rather than allowing them to plate directly on the anode current collector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium ions plate directly on the anode current collector during charging, then high energy density is achieved, but the battery cell swells and components degrade

Engineering Contradiction:

Improveenergy densityVSAvoidcomponent degradation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A buffer layer is introduced as an intermediary between the anode current collector and the solid-state electrolyte. This buffer layer accepts lithium ions during charging, preventing direct plating on the anode current collector and eliminating swelling while maintaining high energy density.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a buffer layer is introduced to reduce swelling, then component degradation is minimized, but device complexity increases

Engineering Contradiction:

Improvecomponent degradationVSAvoidbattery structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The buffer layer is designed with a porous structure that allows it to accommodate lithium ions during charging. The porosity enables ion storage without requiring complex mechanical expansion structures, simplifying the overall design while effectively preventing swelling and component degradation.

Inventive Principle:

Principle #31Porous materials

3Volume of stationary object

If lithium ions are stored in the buffer layer, then swelling is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvebattery cell volumeVSAvoidlayer thickness control

Core Design Contradiction:

Volume of stationary objectVSManufacturing precision

Solution Approach 1:

The buffer layer's porosity and thickness are optimized to accommodate the expected volume of lithium ions during charging. By carefully selecting these parameters, the buffer layer can absorb ion storage demands without requiring extremely tight manufacturing tolerances, making production more feasible.

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 buffer layer significantly reduces swelling during charge and discharge cycles, prolonging the battery's life by minimizing pressure on components and maintaining high energy and power densities, with at least 80% of lithium ions stored within the buffer layer during full charge.

Implementation Method 1

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS11515539B2Volume-expansion accommodable anode-free solid-state battery

Publication Date: 2022.11.29 TERAWATT TECHNOLOGY INC

AI summary

Various arrangements of an anode-free battery cell are presented herein. The battery cell can include a lithium ion buffer layer that is located between a electrolyte and an anode current collector. Lithium ions may be stored within the lithium ion buffer layer when the battery cell is charged, which can decrease an amount of swelling within the battery cell.