Voltage-Reduction Circuit for Fuel Cell Stack Diagnostics

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Solution Overview

Problem

Current diagnostic tools for PEM fuel cells are inadequate in detecting hydrogen leaks in large stacks, as existing methods are not effective in quantifying hydrogen leak rates, leading to performance degradation and potential safety issues due to the lack of appropriate models for larger systems.

Innovation Solution

A low voltage interface is introduced that couples a DC power source to an AC signal diagnostic system, utilizing a voltage-reduction circuit to reduce the DC component of the input voltage without affecting the AC component, allowing for efficient diagnostic systems operation while reducing high voltage hazards and enabling the use of lower-cost electronics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a diagnostic system is used to detect hydrogen leaks in large fuel cell stacks, then measurement precision is improved, but device complexity increases due to the need for high voltage isolation and specialized high-voltage electronics

Engineering Contradiction:
Improvehydrogen leak detection capabilityVSAvoidhigh voltage isolation requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A voltage reduction circuit is introduced as an intermediary component between the high-voltage fuel cell stack and the diagnostic system. This circuit steps down the high voltage to a lower voltage level that standard electronics can handle, while maintaining signal integrity for accurate hydrogen leak detection through impedance spectroscopy measurements

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a low-voltage copy or representation of the high-voltage stack electrical characteristics. By measuring impedance at reduced voltage levels, the system obtains equivalent diagnostic information about hydrogen leaks without requiring the measurement equipment to directly withstand high voltages, thus simplifying the device complexity

Inventive Principle:
Principle #26Copying

2Device complexity

If standard electronics are used in the diagnostic system, then device complexity is reduced, but reliability decreases due to exposure to high voltage shocks and safety hazards

Engineering Contradiction:
Improveelectronics cost and complexityVSAvoidhigh voltage safety and operational reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The voltage reduction circuit serves as a protective intermediary that isolates standard electronics from high voltage exposure. By placing this circuit between the high-voltage stack and the diagnostic electronics, the system maintains reliability and safety while allowing the use of cheaper, less complex standard electronic components

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention enables the use of lower-cost, standard electronic components in the diagnostic system that would normally be unsuitable for high-voltage environments. The voltage reduction circuit protects these less robust, more economical components from high voltage damage, making the overall system more cost-effective while maintaining reliability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution enables reliable and efficient diagnostic systems for PEM fuel cells, reducing the risk of high voltage shock and allowing for the use of lower-cost electronics, thereby improving stack high voltage to low voltage isolation and facilitating effective hydrogen leak detection in larger fuel cell stacks.

Implementation Method 1

a voltage-reduction circuit electrically coupled to the interface input node and the first interface output node, the voltage-reduction circuit: may receive an input voltage from the DC power source via the interface input node, the input voltage comprising a DC component and an AC component; may reduce the DC component of the input voltage without substantially affecting a magnitude or phase of the AC component of the input voltage

Methodology Applied
Scientific EffectVoltage reduction:

Data Source

PatentEP3325987B1Reduced stack voltage circuitry for energy storage system diagnostics
Publication Date: 2021.04.28 BALLARD POWER SYSTEMS INC
  • EP3325987B1 patent drawingFigure 1
  • EP3325987B1 patent drawingFigure 2
  • EP3325987B1 patent drawingFigure 3~4

AI summary

Systems and methods to provide a low voltage interface coupleable between an energy storage device or a DC power source (e.g., fuel cell stack, battery) and one or more AC signal diagnostic systems. The low voltage interface reduces a voltage of the DC power source and supplies the reduced voltage to the one or more AC signal diagnostic systems without affecting the results of the measurements obtained by the one or more AC signal diagnostic systems. Such functionality provides a safer method for performing advanced analysis (e.g., EIS, frequency analysis) while utilizing lower cost and/or smaller components.