Fuel Cell Oxidant Flow Control via Pressure Valve
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Solution Overview
Problem
Fuel cell systems face challenges in efficiently controlling the oxidant gas flow rate to the cathode electrode, particularly when the required flow rate is lower than the minimum supply rate, which can lead to excessive air supply and potential drying of the solid polymer electrolyte membrane.
Innovation Solution
A method for controlling the fuel cell system that involves adjusting the opening degree of the pressure adjusting valve to match the oxidant gas flow rate with the required flow rate, while maintaining the rotational driving unit at the lowest speed, thereby preventing excessive air supply and ensuring precise flow rate adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the rotational driving unit operates at the lowest speed to reduce energy consumption, then energy efficiency is improved, but the oxidant gas supply flow rate becomes insufficient when the required flow rate is lower than the minimum supply rate
Solution Approach 1:
The patent introduces a flow rate adjusting valve as an intermediary device between the rotational driving unit and the cathode electrode. This valve acts as a mediator that can precisely regulate the oxidant gas flow rate independently of the rotational driving unit's speed, allowing the system to maintain low energy consumption while achieving the required low flow rates through valve adjustment rather than reducing motor speed further
Solution Approach 2:
The patent implements dynamic control by independently adjusting the flow rate adjusting valve opening degree based on the required oxidant gas flow rate. This dynamic adjustment mechanism allows the system to adapt the gas flow rate in real-time without changing the rotational driving unit's operating speed, resolving the contradiction between maintaining low energy consumption and achieving precise low flow rate control
2Quantity of substance
If the pressure adjusting valve opening degree is increased to increase oxidant gas supply, then the supply flow rate is improved, but the solid polymer electrolyte membrane may become excessively dry
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors the required oxidant gas flow rate and adjusts the flow rate adjusting valve opening degree accordingly. This feedback system ensures that the oxidant gas flow rate is precisely matched to the actual requirements of the fuel cell, preventing both excessive supply that would cause membrane drying and insufficient supply that would reduce power generation efficiency
Solution Approach 2:
The patent changes the control parameter from pressure adjustment to flow rate adjustment by introducing a flow rate adjusting valve. This parameter change allows direct control of the oxidant gas flow rate based on actual demand, enabling precise matching of gas supply to the membrane's hydration requirements and preventing excessive drying while maintaining adequate supply
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 for precise control of the oxidant gas flow rate, preventing membrane drying and maintaining optimal proton conductivity, even at low required flow rates, thereby enhancing the operational efficiency and longevity of the fuel cell system.
Implementation Method 1
an electrolyte membrane, which is a proton-conductive polymer ion-exchange membrane
Implementation Method 2
an oxidant gas pump (air pump) compresses air and supplies the compressed air to the cathode electrode
Implementation Method 3
The supply pressure of compressed air, that is, the internal pressure of the cathode electrode is controlled by adjusting the opening degree of a pressure adjusting valve
Implementation Method 4
generates electric power by causing an electrochemical reaction between a fuel gas that is supplied through a fuel gas supply channel to the anode electrode and an oxidant gas that is supplied through an oxidant gas supply channel to the cathode electrode
Data Source
AI summary
A method for controlling a fuel cell system including a fuel cell which includes an anode electrode and a cathode electrode sandwiching a solid polymer electrolyte membrane therebetween, includes driving a pump to supply an oxidant gas to the cathode electrode. The pump has a minimum supply amount of the oxidant gas. A fuel gas is supplied to the anode electrode to generate electric power via an electrochemical reaction between the fuel gas and the oxidant gas. It is determined whether a target amount of the oxidant gas to be supplied to the cathode electrode is lower than the minimum supply amount. An opening degree of a pressure adjusting valve is adjusted to adjust an amount of the oxidant gas supplied to the cathode electrode to be the target amount when the target amount is determined to be lower than the minimum supply amount.