Fuel Cell Stack Humidity Control via High Frequency Resistance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Fuel cell systems face operational challenges when errors in cathode air flow estimation occur, leading to potential damage from poor humidification and suboptimal stoichiometry, which can cause the entire stack to malfunction if not addressed.

Innovation Solution

A method that utilizes high frequency resistance measurements to control relative humidity and increase air flow to the fuel cell stack when errors in cathode air flow estimation are detected, ensuring continued operation by bypassing faulty sensors and maintaining minimum stoichiometry levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mass air flow sensors or cathode valves are used to control air flow to the fuel cell stack, then air flow can be regulated for proper humidification and stoichiometry, but system reliability deteriorates when these sensors or valves fail

Engineering Contradiction:

Improvesystem operation continuityVSAvoidsensor and valve system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The fuel cell stack itself serves as the sensing element by monitoring its own performance parameters (voltage, current, temperature) to detect air flow estimation errors, eliminating dependence on external mass air flow sensors and cathode valves for basic operation

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The control system continuously monitors fuel cell performance parameters and uses this feedback to detect deviations from expected operation, triggering remedial actions when air flow estimation errors are identified

Inventive Principle:

Principle #23Feedback

2Reliability

If air flow estimation errors are not detected and corrected, then the system operates with faulty sensor data, but membrane damage occurs from poor humidification and suboptimal stoichiometry

Engineering Contradiction:

Improvemembrane durabilityVSAvoidair flow estimation error

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The control system continuously monitors fuel cell performance parameters (voltage, current, temperature) and compares actual performance against expected performance based on commanded air flow, enabling detection of estimation errors before they cause damage

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system takes preliminary remedial actions by adjusting air flow commands to compensate for detected estimation errors before the errors can cause membrane damage from poor humidification or stoichiometry

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If the system shuts down when air flow estimation errors are detected, then component damage is prevented, but productivity is reduced due to unnecessary system interruptions

Engineering Contradiction:

Improvecomponent protectionVSAvoidsystem availability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of complete system shutdown, the control system applies partial remedial actions by adjusting air flow commands to compensate for detected errors, maintaining system operation while protecting against damage

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system converts the potentially harmful effect of estimation errors into a beneficial opportunity to demonstrate robust control by successfully compensating for errors and maintaining operation, thereby improving overall system reliability

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 approach allows the fuel cell system to continue operating by compensating for air flow errors, preventing damage from humidification issues and maintaining efficient stoichiometry, even when mass air flow sensors or valves fail, thereby extending the life of the fuel cell stack.

Implementation Method 1

utilizing high frequency resistance measurements from a high frequency resistance sensor to control a relative humidity of the fuel cell stack

Methodology Applied

Scientific EffectHigh frequency resistance measurement: Electrical Resistance

Implementation Method 2

use the water to humidify the cathode input airflow. Water in the cathode exhaust gas at one side of the membrane is absorbed by the membrane and transferred to the cathode air stream at the other side of the membrane

Methodology Applied

Scientific EffectWater vapor transfer: Diffusion

Implementation Method 3

Water in the cathode exhaust gas at one side of the membrane is absorbed by the membrane and transferred to the cathode air stream at the other side of the membrane

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS9281532B2Remedial actions for air flow errors in a fuel cell system

Publication Date: 2016.03.08 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system and method for operating a fuel cell stack of a fuel cell system in a vehicle when an error in cathode air flow rate is detected. The system and method include estimating a cathode air flow rate and detecting an error in the estimated cathode air flow rate. The system and method also include utilizing high frequency resistance measurements from a high frequency resistance sensor to control a relative humidity of the fuel cell stack when the error in the estimated cathode air flow rate has been detected.