Lithium Ion 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 at the anode current collector, leading to potential degradation and performance issues.

Innovation Solution

Incorporating a porous lithium ion buffer layer between the solid-state electrolyte and the anode current collector, which is electrically conductive and flexible, to store lithium ions instead of allowing them to plate directly on the anode current collector, thereby reducing swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium ions are allowed to plate directly on the anode current collector to achieve high energy density, then the battery cell swells and components degrade

Engineering Contradiction:

Improvelithium ion storage capacityVSAvoidcomponent integrity

Core Design Contradiction:

Quantity of substanceVSReliability

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 thereby eliminating swelling that causes component degradation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer layer is designed with a porous structure that can accommodate lithium ions within its pores. This porous architecture allows the buffer layer to absorb volume changes from lithium ion insertion and extraction, preventing the swelling that would otherwise damage the anode current collector and other components.

Inventive Principle:

Principle #31Porous materials

2Reliability

If a buffer layer is added to accommodate lithium ions and reduce swelling, then component degradation is slowed, but the device complexity increases

Engineering Contradiction:

Improvecomponent integrityVSAvoidbattery structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The buffer layer is implemented as a thin film structure that is flexible and conformal to the anode current collector. This thin-film approach minimizes the additional volume and structural complexity while still providing effective lithium ion accommodation and swelling prevention.

Inventive Principle:

Principle #30Flexible shells and thin films

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 effectively reduces swelling by accommodating lithium ions within its porous structure, slowing down component degradation and maintaining high energy and power densities, with at least 80% of lithium ions stored within the buffer layer during charging.

Implementation Method 1

Lithium ions can be stored within the lithium ion buffer layer when the anode-free solid-state battery cell is charged

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

During charging, ions, such as lithium ions, migrate from a battery's cathode to the battery's anode through the battery's electrolyte

Methodology Applied

Scientific EffectIon migration: Diffusion

Data Source

PatentUS11069897B2Volume-expansion accommodable anode-free solid-state battery

Publication Date: 2021.07.20 TERAWATT TECHNOLOGY INC

AI summary

Various arrangements of an anode-free solid-state battery cell are presented herein. The battery cell can include a lithium ion buffer layer that is located between a solid-state 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.