Electrochemical Cell Leakage Detection Using Complex Impedance

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Solution Overview

Problem

Existing methods for detecting electrolyte leakage in electrochemical cells fail to differentiate between electrolyte leakage and other conductive liquids, such as tap water, leading to false alarms and safety risks, particularly since they require conductive containers and can cause short-circuits.

Innovation Solution

A setup using a complex impedance measuring device connected to an electrically conductive component, like a metallic mesh, which measures the real and imaginary parts of impedance to distinguish between water vapor condensation, tap water, and electrolyte leakage by calibrating the component's impedance spectra with known contacts and comparing them to determine the presence of electrolyte.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex impedance measuring device is connected to the container wall to detect electrolyte leakage, then leakage detection capability is improved, but the container must be electrically conductive which limits material choices and creates safety risks

Engineering Contradiction:
Improveleakage detection capabilityVSAvoidcontainer material flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an electrically conductive component (such as a metallic mesh or plate) placed at the bottom of the container as an intermediary element. This component serves as the actual sensing surface for impedance measurement, while the container wall itself remains electrically insulating. The conductive component acts as a mediator between the measurement device and the electrolyte, eliminating the need for a conductive container wall while maintaining leakage detection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a potential is applied to the container for impedance measurement, then measurement capability is improved, but safety risks increase due to potential short-circuits and corrosion

Engineering Contradiction:
Improveimpedance measurement capabilityVSAvoidsafety risks from applied potential
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The conductive component serves as an intermediary that isolates the applied measurement potential from the container and surrounding equipment. By placing the conductive component on an electrically insulating support, the measurement potential is confined to the conductive component itself, preventing short-circuits to ground or adjacent structures while still enabling accurate impedance measurements for leakage detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct electrical connection to the container wall with a indirect measurement approach through the conductive component. This substitution allows impedance measurement without requiring the container itself to be conductive or directly connected to the measurement circuit, thereby reducing safety hazards associated with applying potential to the container structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If resistance measurement between two metallic parts is used to detect leakage, then simplicity is improved, but false alarms occur due to inability to differentiate electrolyte from other conductive liquids

Engineering Contradiction:
Improvemeasurement system simplicityVSAvoidliquid type differentiation capability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from measuring only resistance (a single real parameter) to measuring complex impedance (which includes both real and imaginary components). By analyzing the full complex impedance spectrum rather than just resistance, the system can differentiate between electrolyte and other conductive liquids based on their distinct impedance characteristics, eliminating false alarms while maintaining practical system complexity.

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 and safe detection of electrolyte leakage without false alarms, allowing for real-time differentiation between electrolyte and other conductive liquids, and permits the use of non-conductive cell containers, reducing safety risks and maintaining system integrity.

Implementation Method 1

a complex impedance measuring device configured to measure the complex impedance of the electrically conductive component

Methodology Applied
Scientific EffectComplex impedance measurement: Electrical Resistance

Implementation Method 2

as the electrolyte is generally a highly ionic conductive solution, an electrolyte leakage may lead to a short-circuit if it comes into contact with two metal surfaces of different potentials

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP4303985A1Apparatus and method for detecting electrolyte leakage in an electrochemical cell
Publication Date: 2024.01.10 SAFT GRP
  • EP4303985A1 patent drawingFigure 1~2
  • EP4303985A1 patent drawingFigure 3~4
  • EP4303985A1 patent drawingFigure 5~6

AI summary

A set-up for detecting an electrolyte leakage from an electrochemical cell, the set-up comprising: - at least one electrochemical cell (2) containing an electrolyte, - an electrically conductive component (3) placed with respect to said at least one electrochemical cell so that it is exposed to the electrolyte in case of an electrolyte leakage, - a complex impedance measuring device (4, 5, 6) configured to measure the complex impedance of the electrically conductive component. This set-up is useful for distinguishing whether there is an electrolyte leakage or whether any other fully or partially conductive liquid has condensed at the surface of the electrically conductive component.