Self-Aligning Fiber Powders for High Density Battery Electrodes

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Solution Overview

Problem

Existing battery electrodes face challenges in achieving high packing density of active materials while minimizing tortuosity, which affects rate performance and increases manufacturing costs and processing times.

Innovation Solution

The use of self-aligning short fiber powders with a cylindrical morphology, which align during the coating process due to shear forces, resulting in a closed packed arrangement that increases packing density to 0.91 without raising manufacturing costs or processing times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If smaller particles are placed into interstitial spaces between spherical particles to improve packing density, then packing density is improved, but manufacturing complexity and cost increase significantly

Engineering Contradiction:

Improvepacking densityVSAvoidmanufacturing complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The invention changes the particle morphology parameter from spherical to cylindrical/rod-like shape. This parameter change enables the particles to self-align and pack more efficiently (achieving 0.91 packing density) without requiring complex multi-step filling processes. The aspect ratio of the cylindrical particles (length-to-diameter ratio) is specifically optimized to enable both high packing density and self-alignment during coating.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If smaller particles are used to fill interstitial spaces to improve packing density, then packing density is improved, but tortuosity significantly increases

Engineering Contradiction:

Improvepacking densityVSAvoidtortuosity

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention introduces asymmetry in particle shape by using cylindrical/rod-like particles with specific aspect ratios instead of spherical particles. This asymmetric shape enables the particles to align in preferred orientations during the coating process, creating a more ordered structure that achieves high packing density while minimizing tortuous pathways. The alignment reduces random positioning that would otherwise increase tortuosity.

Inventive Principle:

Principle #4Asymmetry

3Ease of manufacture

If traditional spherical particles are used in electrode manufacturing, then manufacturing process is simple, but packing density is limited to maximum of 0.74

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidpacking density

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

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

This approach enhances the volumetric capacity by 17% and mitigates the adverse effects of tortuosity on rate performance, providing improved electrode architecture for batteries.

Implementation Method 1

The short fiber powders self-align during a slurring coating process as a result of shear forces between a die and a foil for example

Methodology Applied

Scientific EffectShear forces: Shear Stress

Data Source

PatentUS10199633B2Method of manufacturing high volumetric density electrodes from self-aligning fiber powders

Publication Date: 2019.02.05 UT BATTELLE LLC

AI summary

An electrode and a related method of manufacture are provided. The electrode includes a self-aligning active material having short fiber powders with a cylindrical morphology to increase the packing density from 0.74 to nearly 0.91. The short fiber powders self-align during a slurring coating process as a result of shear forces between a die and a foil. The resulting coating includes parallel short fibers in a closed packed arrangement, providing an increased volumetric capacity of at least approximately 17%.