Fuel Cell Voltage Recovery Strategy

Solution Overview

Problem

Fuel cell stacks experience reversible voltage losses due to factors like membrane drying and contamination, which are not effectively addressed by existing methods, impacting stack performance and stability, especially at low load conditions.

Innovation Solution

A system and method that estimate irreversible and actual stack voltages, determining a voltage delta to trigger a voltage recovery process when the difference exceeds a threshold, using a controller to implement algorithms for recovering reversible losses by adjusting humidity and gas flow, and potentially notifying operators of maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a voltage recovery algorithm is continuously operated to recover reversible voltage loss, then stack performance is improved, but energy consumption increases and system complexity increases

Engineering Contradiction:

Improvestack performanceVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs preliminary estimation of irreversible voltage loss and actual stack voltage to determine the voltage delta before initiating recovery algorithms. This preliminary assessment allows the system to only activate recovery algorithms when reversible voltage loss is present, avoiding continuous operation and reducing unnecessary energy consumption while maintaining stack performance when needed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors stack voltage, estimates irreversible voltage loss, and compares actual voltage against expected voltage to calculate voltage delta. This feedback mechanism enables the system to dynamically adjust recovery algorithm activation based on real-time stack condition, ensuring performance improvement only when beneficial while minimizing energy waste

Inventive Principle:

Principle #23Feedback

2Reliability

If voltage recovery algorithms are operated at all times, then reversible voltage loss is recovered, but device complexity increases

Engineering Contradiction:

Improvestack performanceVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary estimation of irreversible voltage loss and actual stack voltage to determine the voltage delta before initiating recovery algorithms. This preliminary assessment allows the system to only activate recovery algorithms when reversible voltage loss is present, avoiding continuous operation and reducing unnecessary energy consumption while maintaining stack performance when needed

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors stack voltage, estimates irreversible voltage loss, and compares actual voltage against expected voltage to calculate voltage delta. This feedback mechanism enables the system to dynamically adjust recovery algorithm activation based on real-time stack condition, ensuring performance improvement only when beneficial while minimizing energy waste

Inventive Principle:

Principle #23Feedback

3Reliability

If humidity is increased to prevent membrane drying, then membrane performance is improved, but water accumulation in flow channels occurs

Engineering Contradiction:

Improvemembrane performanceVSAvoidwater accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system applies different humidity control strategies to different locations within the fuel cell stack. By monitoring local conditions in flow channels versus membrane requirements, the system can provide targeted humidification where needed while allowing drainage in areas prone to water accumulation, thus maintaining membrane performance without causing harmful water buildup

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts humidity levels based on real-time operating conditions, load demands, and detected water accumulation patterns. This dynamic control allows the system to increase humidity when membranes are drying out while reducing humidity or enhancing drainage when water accumulation is detected in flow channels, balancing membrane performance with prevention of harmful effects

Inventive Principle:

Principle #15Dynamics

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

The method effectively recovers reversible voltage losses, maintaining stack performance and extending the life of fuel cell systems by adapting to different operational conditions and driver behaviors, while also indicating when replacement is necessary.

Implementation Method 1

use a water vapor transfer (WVT) unit to capture some of the water in the cathode exhaust gas, and use the water to humidify the cathode input airflow. Water in the cathode exhaust gas at one side of the water transfer elements, such as membranes, is absorbed by the water transfer elements and transferred to the cathode air stream at the other side of the water transfer elements

Methodology Applied

Scientific EffectWater vapor transfer: Permeation

Data Source

PatentUS9178233B2Smart in-vehicle reactive recovery strategy

Publication Date: 2015.11.03 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A method for determining when to operate a voltage recovery process for recovering a reversible voltage loss of a fuel cell stack in a fuel cell system. The method includes estimating an irreversible voltage loss of the fuel cell and an actual voltage of the fuel cell stack, and determining whether a difference between the estimated irreversible voltage loss and the estimated actual voltage exceed a threshold, and if so, the voltage recovery process is performed.