Fuel Cell Separator Internal Resistance Measurement

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Solution Overview

Problem

Conventional internal resistance measuring devices for laminated batteries do not account for voltage drops in non-power generation regions, leading to errors in calculated internal resistance measurements.

Innovation Solution

A separator with distinct source and sense connection points, and a separation portion that isolates the sense connection point from the current path to the power generation region, ensuring accurate measurement by minimizing the impact of voltage drops on the intermediate sense potential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the sense line is connected to the separator in the same path as the source line to simplify the structure, then the device complexity is reduced, but the measurement precision deteriorates due to voltage drop in the non-power generation region affecting the sense line potential

Engineering Contradiction:

Improvestructure complexityVSAvoidinternal resistance measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The separator is divided into distinct functional regions: a power generation region where current flows through the membrane electrode assembly, and a non-power generation region where the sense line is isolated. This segmentation allows the sense line to detect potential without being affected by voltage drops in the current path, resolving the contradiction between structural simplicity and measurement accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The non-power generation region of the separator acts as an intermediary zone that electrically isolates the sense line connection point from the current path. This intermediary region allows the sense line to access the separator potential at a point unaffected by ohmic voltage drops, enabling accurate measurement while maintaining a simple single-path connection structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the sense line is isolated from the current path to improve measurement accuracy, then the measurement precision is improved, but the device complexity increases due to the need for separate connection paths

Engineering Contradiction:

Improveinternal resistance measurement accuracyVSAvoidconnection path complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The sense line and source line are merged into a single physical path through the separator, but functional isolation is achieved by selecting the sense line connection point in the non-power generation region. This merging approach simplifies the overall structure while maintaining measurement accuracy, as both lines traverse the same separator material but access different functional regions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The separator serves multiple functions: it acts as both the medium for current flow in the power generation region and as the sensing medium in the non-power generation region. This multi-functionality allows a single separator structure to support both power generation and potential sensing without requiring separate isolation structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If the sense connection point is located close to the source connection point to minimize potential difference, then the measurement accuracy is improved, but the voltage drop effect from the non-power generation region cannot be eliminated

Engineering Contradiction:

Improvepotential detection accuracyVSAvoidvoltage drop effect

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The non-power generation region, which would normally be considered a source of measurement error due to voltage drops, is instead utilized as the optimal location for the sense line connection. By placing the sense connection in this region, the voltage drop that would affect a power generation region connection is converted into a benefit: the sense line measures the true separator potential without ohmic losses, improving measurement accuracy.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 configuration improves the accuracy of internal resistance measurements by reducing the effect of separator resistance on the measured potential, thereby aligning the calculated internal resistance with the actual resistance.

Implementation Method 1

the alternating-current potential input to the internal resistance measuring device via the sense line has been affected by the voltage drop caused in the non-power generation region of the separator

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3125344B1Laminated battery, separator and connection method of internal resistance measuring device

Publication Date: 2018.10.17 NISSAN MOTOR CO LTD

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AI summary

A separator of a fuel cell to be laminated while sandwiching a membrane electrode assembly forming a power generation region includes a source connection point tab for inputting and outputting an alternating current for internal resistance measurement, a sense connection point tab for detecting a potential of the alternating current input and output to and from the source connection point tab and separation portion configured to separate the sense connection point tab from a current path of the alternating current for internal resistance measurement from the source connection point tab to the power generation region.