Fuel Cell Scavenging Control for Battery Power Conservation
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Solution Overview
Problem
In fuel cell systems, scavenging processing that removes water after power generation stops depletes the secondary cell's electrical power, reducing the operational time of Electric Vehicles (EVs) when performed due to running out of gas.
Innovation Solution
A fuel cell system with a power storage unit, scavenging processing execution means, and judgment means that limits scavenging processing when an abnormal condition occurs, such as running out of gas, to conserve electrical power by shortening or prohibiting the scavenging process, and reducing oxidant gas supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scavenging processing is performed after fuel cell power generation stops, then remaining water in the fuel cell is removed, but electrical power stored in the power storage unit is depleted, reducing EV operation time
Solution Approach 1:
The scavenging processing execution means dynamically adjusts whether to execute scavenging processing based on the stopping reason of fuel cell power generation. When stopping due to abnormal conditions (other than gas depletion), scavenging processing is executed to maintain system reliability. When stopping due to gas depletion, scavenging processing is prohibited to conserve battery power and extend EV operation time. This dynamic decision-making resolves the contradiction by adapting system behavior to specific operational contexts.
2Reliability
If scavenging processing is executed using electrical power from the power storage unit, then water removal is achieved, but the amount of electrical power stored in the power storage unit decreases
Solution Approach 1:
The system changes the operational parameter of scavenging processing execution based on the stopping reason. When the fuel cell stops due to abnormal conditions, the parameter is set to execute scavenging processing to ensure reliability. When the fuel cell stops due to gas depletion, the parameter is set to prohibit scavenging processing to preserve battery charge. This parameter change strategy resolves the contradiction between maintaining reliability and preserving electrical power quantity.
3Object-affected harmful factors
If scavenging processing is performed to remove remaining water, then freezing damage is prevented, but the compressor operates longer consuming more electrical power from the battery
Solution Approach 1:
The scavenging processing execution means dynamically controls compressor operation based on the stopping reason. For abnormal condition stoppages, the compressor operates to remove water and prevent freezing damage. For gas depletion stoppages, the compressor operation is prohibited to conserve battery energy. This dynamic control resolves the contradiction between preventing freezing damage and reducing battery energy consumption.
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 configuration increases the operational time of the battery by conserving electrical power during scavenging processing after fuel cell power generation stops, especially when the fuel cell system encounters abnormal conditions like running out of gas.
Implementation Method 1
a fuel cell which is supplied with a fuel gas and an oxidant gas and which generates electrical power through an electrochemical reaction between the fuel gas and the oxidant gas
Implementation Method 2
a power storage unit which can be charged with electric power generated by the fuel cell
Data Source
AI summary
Even in a fuel cell system which performs scavenging processing after the power generation of a fuel cell is stopped, the operation time for when a battery is being operated can be increased. When determining that the condition of running out of gas occurs based on a sensor value of a pressure sensor, a control unit stops the power generation of the fuel cell. The control unit, for example, shortens the time required for scavenging processing and then performs the scavenging processing. On the other hand, when determining that the condition of running out of gas does not occur and when the power generation of the fuel cell should be stopped, the control unit stops the power generation and then performs normal scavenging processing.