Fuel Cell Startup Using Exhaust Gas Recirculation Pump for Low Battery SOC
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Solution Overview
Problem
Long-term vehicle inactivity leads to reduced State of Charge (SOC) in high-voltage batteries, preventing the air pump from rotating and thus hindering the startup of the fuel cell system and vehicle operation due to insufficient oxygen supply.
Innovation Solution
A method involving an exhaust gas recirculation pump driven by a low-voltage battery to circulate atmosphere as oxygen-containing gas and supply fuel gas from a fuel tank, initiating power generation to charge the high-voltage battery, and switching to the air pump once the battery voltage reaches a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle is left inactive for a long time, then the high-voltage battery SOC is reduced, but the air pump cannot be rotated, preventing fuel cell system startup
Solution Approach 1:
The exhaust gas recirculation pump is activated in advance to perform preliminary power generation before the air pump can operate. This preliminary action charges the high-voltage battery to a sufficient SOC level, enabling subsequent normal operation with the air pump.
Solution Approach 2:
The exhaust gas recirculation pump serves as an intermediary device that bridges the gap between low SOC state and air pump operation. It temporarily performs the oxygen supply function that the air pump would normally provide, allowing the system to transition from a non-operational state to a operational state.
2Ease of operation
If the exhaust gas recirculation pump is used for startup, then power generation can be initiated, but the system complexity increases
Solution Approach 1:
The control system dynamically switches between different pump operations based on real-time SOC levels. The exhaust gas recirculation pump operates during startup when SOC is low, and the air pump takes over when SOC is sufficient, creating a flexible and adaptive operational mode.
Solution Approach 2:
The exhaust gas recirculation pump performs multiple functions: it serves its original exhaust gas recirculation role and additionally functions as a temporary oxygen supply device during startup. This multi-functionality reduces the need for separate dedicated startup mechanisms.
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
Enables the startup and normal operation of the fuel cell system by charging the high-voltage battery, allowing the air pump to supply necessary oxygen for power generation, even when the SOC is low.
Implementation Method 1
a fuel cell stack (34) having a power generation capability to generate power by using the oxygen-containing gas and the fuel gas
Implementation Method 2
a high-voltage battery (14) having a state of charge (SOC)
Data Source
AI summary
When operation is to be started in a state where the SOC of a high-voltage battery has dropped, an exhaust gas recirculation pump is driven by a low-voltage battery to suck in atmosphere through an air intake valve. The atmosphere is supplied to a fuel cell stack as oxygen-containing gas, while fuel gas is supplied from a fuel tank thereto, whereby power generation is performed to thereby charge the high-voltage battery. Normal power generation of the fuel cell system is performed using the high-voltage power of the charged high-voltage battery.