Fuel Cell Idle-Stop Air Control for Stack Voltage Stability
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Solution Overview
Problem
Existing fuel cell systems face durability issues during idle stop states due to voltage decrease and hydrogen crossover, leading to weakened performance when the idle stop state is maintained for a long time.
Innovation Solution
An apparatus and method that control the air compressor and Airflow Control Valve (ACV) to maintain a reference output voltage range in the fuel cell stack by adjusting air supply and discharge, including driving the air compressor at a lowest level and controlling the ACV opening degree, with additional management of the Fuel Discharge Valve (FDV) when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the air compressor is stopped to improve fuel efficiency during idle stop state, then energy consumption is reduced, but the hydrogen concentration continuously decreases causing fuel cell stack durability to deteriorate
Solution Approach 1:
The control device operates the air compressor in a periodic manner during idle stop state - turning it on at specific intervals to supply air to the cathode, and turning it off between intervals to save energy. This periodic operation maintains sufficient hydrogen concentration and prevents durability deterioration while achieving energy efficiency during extended idle stop periods.
2Reliability
If the air compressor is operated continuously to maintain hydrogen concentration, then fuel cell stack durability is improved, but energy consumption increases
Solution Approach 1:
Instead of continuous operation, the air compressor is controlled to operate periodically with calculated on/off intervals based on the idle stop duration and fuel cell stack characteristics. This maintains adequate hydrogen concentration for durability while significantly reducing energy consumption compared to continuous operation.
3Use of energy by moving object
If the fuel cell power generation is stopped completely during idle stop state, then fuel efficiency is improved, but the output voltage decreases to 0V causing durability to deteriorate
Solution Approach 1:
The control device performs preliminary action by operating the air compressor before the idle stop state begins, pre-conditioning the fuel cell stack with adequate air supply. During the idle stop state, this preliminary preparation helps maintain sufficient hydrogen concentration and voltage levels, preventing durability deterioration even when power generation is temporarily stopped for fuel efficiency.
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
Prevents degradation of the fuel cell stack durability by maintaining optimal voltage and hydrogen concentration, ensuring efficient operation upon restarting.
Implementation Method 1
hydrogen ions are separated from the fuel electrode through a catalytic reaction. The separated hydrogen ions are transferred to an oxidation electrode that is the air electrode through an electrolyte membrane, and in the oxidation electrode, the hydrogen ions separated from the fuel electrode, electrons, and the oxygen generate an electrochemical reaction together, thereby obtaining electrical energy
Implementation Method 2
hydrogen ions are separated from the fuel electrode through a catalytic reaction
Implementation Method 3
The separated hydrogen ions are transferred to an oxidation electrode that is the air electrode through an electrolyte membrane
Implementation Method 4
the air supply system supplies external air suctioned by operating an air blower to an air electrode (cathode) of the fuel cell stack
Data Source
AI summary
The present disclosure relates to an apparatus for controlling an operation of a fuel cell system and a method therefor. The present disclosure may include a voltage sensor that measures an output voltage of a fuel cell stack, an air compressor that supplies air to a cathode of the fuel cell stack, a valve driver that adjusts an opening degree of an Airflow Control Valve (ACV), and a controller that, in an idle stop state, drives the air compressor at a lowest level and controls the opening degree of the ACV such that the output voltage of the fuel cell stack maintains a reference range.