Battery Degradation Detection via Multi-Frequency Impedance

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Solution Overview

Problem

Existing battery degradation detection methods fail to detect corrosion of the current collecting portion, and accurately measuring internal battery temperature is challenging.

Innovation Solution

A battery degradation detection device and a battery temperature estimation device that utilize impedance measurement units to detect degradation by analyzing real components of impedance at multiple frequencies, with at least one frequency having a positive imaginary component, allowing for the detection of corrosion and estimation of internal temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional impedance measurement methods are used to detect battery degradation, then electrolyte solution and electrode degradation can be detected, but corrosion of the current collecting portion cannot be detected

Engineering Contradiction:

Improvedetection capabilityVSAvoidcorrosion detection information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent changes the measurement parameter by using impedance at frequencies with positive imaginary components (inductive region) instead of conventional frequencies. This parameter change enables detection of current collecting portion corrosion while maintaining the ability to detect other degradation types, thus resolving the information loss problem.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If exterior temperature measurement is used to monitor battery temperature, then temperature monitoring is simple, but internal battery temperature cannot be accurately measured

Engineering Contradiction:

Improvetemperature measurement simplicityVSAvoidinternal temperature accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses impedance measurement as an intermediary to indirectly measure internal battery temperature. By measuring impedance at specific frequencies and using the real component values, the system can estimate internal temperature without direct physical contact, thus maintaining ease of operation while improving measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 detection of battery degradation due to corrosion and estimation of internal battery temperature, improving battery performance monitoring and maintenance.

Implementation Method 1

an impedance measurement unit for measuring impedances of a battery at a plurality of frequencies

Methodology Applied

Scientific EffectElectrical Impedance: Electrical Resistance

Data Source

PatentUS11467218B2Battery degradation detection device and battery temperature estimation device

Publication Date: 2022.10.11 MITSUBISHI ELECTRIC CORP

AI summary

The battery degradation detection device includes an impedance measurement unit and a degradation detection unit. The impedance measurement unit measures impedances of a battery at a plurality of frequencies. The impedance for at least one of the plurality of frequencies, measured by the impedance measurement unit, has a positive imaginary component. The degradation detection unit detects degradation of the battery on the basis of real components of the impedances at the plurality of frequencies detected by the impedance measurement unit.