Battery Resonance Detection for Lithium Plating Monitoring

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Solution Overview

Problem

Existing methods for determining lithium-ion secondary battery degradation, such as those involving lead storage batteries, do not effectively consider lithium-deposition-related degradation and require complex measurements like freezing temperature analysis, necessitating a simpler and more straightforward technique for detecting lithium-ion battery states.

Innovation Solution

A detection device using a resonator circuit applies specific frequency vibrations to lithium-ion secondary batteries, measuring resonant-current attenuation characteristics to estimate battery resistance and detect lithium deposition and coating formation, allowing for the detection of internal states like lithium deposition and foreign metal presence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If freezing temperature measurement and volume measurement are used to determine lithium deposition, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvelithium deposition detection accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary measurement parameter (impedance at specific frequencies) from the complex set of measurements (freezing temperature, volume, impedance spectrum), eliminating unnecessary measurement systems while retaining detection accuracy for lithium deposition

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the measurement parameter from multiple physical quantities (freezing temperature, volume) to electrical impedance at specific frequencies, simplifying the measurement system while maintaining detection capability through frequency-selective impedance measurement

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If impedance measurement at multiple frequencies is performed, then lithium deposition detection accuracy is improved, but measurement time increases

Engineering Contradiction:
Improvelithium deposition detection accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the critical frequency points (resonant frequency and specific bands) from the full impedance spectrum, performing measurements only at these selected frequencies to reduce measurement time while maintaining detection accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs partial impedance measurement at selectively chosen frequencies rather than complete spectrum analysis, using just enough measurement points to detect lithium deposition without excessive measurement time

Inventive Principle:
Principle #16Partial or excessive action

3Ease of operation

If simple impedance measurement is performed, then ease of operation is improved, but detection precision deteriorates

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidlithium deposition detection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the measurement approach from simple single-frequency impedance to multi-frequency impedance measurement, enabling detection of frequency-dependent changes that indicate lithium deposition while maintaining operational simplicity through automated measurement

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If comprehensive degradation analysis is performed, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvedegradation detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the key indicator (impedance at resonant frequency and specific bands) from comprehensive degradation analysis, focusing measurement on the most sensitive parameters for detecting both lithium deposition and capacity degradation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a multi-functional measurement system that can detect multiple degradation modes (lithium deposition, capacity degradation, collector corrosion) using the same impedance measurement approach across different frequency bands

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables the detection of lithium-ion battery states using a simplified configuration and technique, allowing for onboard monitoring of lithium-ion secondary batteries during use, effectively estimating internal conditions like lithium deposition and coating formation.

Implementation Method 1

a resonator circuit applying at least one specific frequency vibration to the lithium-ion secondary battery, measures an attenuation characteristic of at least one resonant current

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

the controller detects lithium deposition and/or presence of foreign metal inside the lithium-ion secondary battery by using the detection signal of the attenuation characteristic

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4323786B1Detection device, management apparatus, and detection method
Publication Date: 2025.01.15 KK TOYOTA CHUO KENKYUSHO
  • EP4323786B1 patent drawingFigure 1
  • EP4323786B1 patent drawingFigure 2
  • EP4323786B1 patent drawingFigure 3~4

AI summary

A detection device includes a detector and a controller. The detector has at least one resonator circuit applying at least one specific frequency vibration to a lithium-ion secondary battery, measures an attenuation characteristic of at least one resonant current, and outputs the attenuation characteristic as a detection signal. The controller detects lithium deposition and/or presence of foreign metal inside the lithium-ion secondary battery by using the detection signal of the attenuation characteristic acquired from the detector.