Detailed Description
A Flemish research institute has developed a reliable, low cost and compact voltage monitoring system for on-site control and diagnosis of fuel cell stacks. The patented monitoring system has been evaluated in the field. The research institute is interested in a technical collaboration with industrial partners active in fuel cell stack manufacturing or system integrators; also a non-exclusive licensing of the technology is possible.
Description:
In order to operate fuel cell stacks in a proper way (maximum life time, minimal cost, maximum performance, safety,…), it is necessary to monitor continuously individual cell voltages. The main technical difficulty of this cell voltage monitoring system (CVM) is the fast measurement of the cell voltage range under the fuel cell stack conditions of -20–80°C with up to 100%RH. A reliable, cheap and compact monitoring system has been developed by a Flemish research institute. For safety, control and diagnosis it has the following features:
- Safety:
configurable relay and transistor output (fail-safe).
- Control:
transmission of, at least, minimum and maximum cell voltage;
extra information like individual cell voltages, current and temperature is possible;
measurement of all cells at the same time, between -150 and 1100 mV;
output for control action, e.g. short hydrogen purging, is an option.
- Diagnosis:
data compression and acquisition on a memory card;
visualisation software for stack life;
statistical analysis of cell behaviour.
The layout of the CVM can be adapted to specific stack dimensions. Galvanic isolation up to 3 kVolt is realised. Process data can be transferred over a CAN-bus and RS232. A conversion rate of 800 cells/second is realised. This monitoring system is patented and is available for demonstration. Several units have been built and evaluated by different fuel cell companies. A licensing of the technology is proposed. This transfer of technology can be done in a technical cooperation through a joint further development or through adaptation of the technology to specific needs of a fuel cell stack manufacturer or system integrator.
Innovative Aspects:
- Modular system
- Compatible with multi-stack systems
- Electrical connections are realised over isolated internal data and power bus
- High common mode rejection (90 dB)
- Low component count
- Galvanic isolation up to 3 kVolt
- Possibility to detect cell voltages below 0 Volt
- Conversion accuracy 10 mV
- Power requirement is 50 mWatt/cell
- Built-in data-acquisition for stack diagnosis
Main advantage:
The electrical design allows a relatively cheap production (< 20 euro/cell) of the monitoring system compared with the obtained accuracy of the voltage measurement.
