Battery Electrode Image Analysis Using Ion-Milled Brightness Patterns

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Solution Overview

Problem

Conventional digital image correlation (DIC) methods struggle to analyze the state of electrodes in batteries, particularly in lithium-ion batteries, due to the thin thickness of electrodes and the presence of voids and electrolyte infiltration, making it difficult to form a random pattern on the electrode cross-section.

Innovation Solution

An analysis device and method that utilize ion milling to process the electrode surface, acquiring image data representing active materials and voids or fillings by brightness differences, and comparing patterns between different states to calculate displacement, layer thickness changes, strain distribution, and displacement distribution using image data from scanning electron or confocal microscopes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional DIC with spray application is used to analyze electrode cross-section, then random pattern can be formed on material surface, but it cannot be applied to battery electrodes due to thin thickness and voids structure

Engineering Contradiction:

Improveapplicability of DIC methodVSAvoiddifficulty to form random pattern on electrode

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses ion milling to create a physical replica/copy of the electrode cross-section surface topography. Instead of applying a random pattern to the actual electrode surface, the ion milling process carves a replica that captures the surface features, which then serves as the analysis target for DIC, bypassing the need to form patterns on the original thin and void-containing electrode structure

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the spray application mechanical process with ion milling. Instead of mechanically spraying material onto the electrode surface to create a random pattern, ion milling uses ion beam bombardment to directly etch and reveal the surface topography, creating the necessary pattern structure through a different physical mechanism that is suitable for thin electrode materials

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If ion milling is applied to process electrode surface for DIC analysis, then accurate surface topography can be obtained, but additional processing step is required

Engineering Contradiction:

Improveaccuracy of electrode analysisVSAvoidnumber of processing steps

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The ion milling process is performed as a preliminary action before DIC analysis. By pre-processing the electrode cross-section with ion milling to create the surface topography replica, the subsequent DIC analysis can proceed with high accuracy without requiring complex real-time pattern formation or additional measurement steps during the actual analysis phase

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If confocal microscope is used instead of scanning electron microscope, then cost is reduced, but image processing requirements increase

Engineering Contradiction:

Improvecost effectiveness of analysis systemVSAvoidimage processing complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the imaging parameters and data format handling when using confocal microscopy. Since confocal microscopes produce different image characteristics compared to SEM, the patent applies specific image processing transformations and parameter adjustments to convert the confocal images into a format suitable for DIC analysis, enabling the use of lower-cost equipment while maintaining analysis accuracy

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

Enables accurate analysis of battery electrodes by applying DIC to challenging battery structures, allowing for the use of cost-effective confocal microscopes and reducing recognition errors from color changes, suitable for both solid and liquid battery systems.

Implementation Method 1

image data that represents active materials in the active material layer processed by ion milling and voids or fillings between the active materials by a difference in brightness

Methodology Applied

Scientific EffectIon milling:

Data Source

PatentUS11977009B2Analysis device, analysis method, and storage medium

Publication Date: 2024.05.07 HONDA MOTOR CO LTD

AI summary

An analysis device of an embodiment is an analysis device of an active material layer of an electrode of a secondary battery, and includes a processor configured to execute a program to acquire image data that represents active materials in the active material layer processed by ion milling and voids or fillings between the active materials by a difference in brightness, and compare patterns of the difference in brightness between the image data in at least two different states of the active material layer.