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Electric battery car with small fuel cells


Methanol and natural gas can both be used as fuel for fuel-cell powered vehicles, provided there is a cheap, compact reformer for conversion to hydrogen available. Full-cycle efficiency favours natural gas since methanol is produced from natural gas at 65-70% efficiency. The objective of this project is to develop a compressed natural gas (CNG) reformer to supply hydrogen to fuel cell driven electric cars. A CNG reformer which supplies hydrogen to a 5 kW fuel cell will be developed and a reformer for a 20 kW fuel cell designed.
Studies with the electric vehicle showed that, for urban use at low average speeds, the range depended on the CNG tank capacity rather than on the battery capacity. The maximum daily range could increase from 90 km to 250 km if the car was refuelled regularly with natural gas. When the reformer needed to power, a 5 kW fuel cell was operated under a range of conditions, the methane conversion varied between 85-92% and the efficiencies between 55-58%. The lowest achievable CO content of the reformat was 0.7 Vol%. However, since PEM fuel cells are very sensitive to CO, this indicates that additional gas clean-up would be needed. Traces of sulphur compounds were identified in the natural gas, but these could be removed in a desulphurisation system, based on active carbon, at a low cost.
In the first phase of the project a 1 kW fuel cell back-up system for an electric car will be studied (TNO). The system comprises a hydrogen supply system including CNG storage and reforming and a 1 kW solid polymer fuel cell. The study should yield a reliable basis for the technical realization of the required hardware. It will be based on the car construction, chosen driving cycles and the expected technical properties of the system components. The integration of a 1 kW system into an electric car will be investigated in a design study (HBZ).

In the second project phase a hydrogen supply device will be developed. NG reformer for 1 kW and 5 kW fuel cells (FhG-ISE) and a CNG storage and supply suitable for connection to both reformers (TNO) will be built up. The NG reformers include integrated catalytic NG burners and will produce 700 l/h hydrogen (for a 1 kW fuel cell with 50% electrical efficiency) and 3200 l/h hydrogen (for a 5 kW fuel cell with 50 % electricity efficiency). Developmental work includes reformer modelling, design and construction and as an essential task, the removal of CO from the reformate. The design of a reformer for a 20 kW fuel cell will also be carried out on the basis of the experimental experience gained with the smaller systems (FhG-ISE).
During the third phase, brass boards (storage tank and reformer combined) for 1 kW and 5 kW fuel cell will be built up and tested (FhG-ISE and TNO).

Funding Scheme

CSC - Cost-sharing contracts


Heidenhofstrasse 2
79110 Freiburg (In Breisgau)

Participants (2)

Hotzenblitz Mobile GmbH
Unteribach 13
79837 Ibach
Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek
2600 JA Delft