The allowable cost of Solid Polymer Fuel Cell (SPFC) systems for road traction is of the order of 400 ECU/kW and 150-200 ECU/kW for buses and private cars respectively. The current cost of SPFC is much higher and the major aim of R&D projects is to reduce the cost of SPFC to acceptable levels.
This project is intended to develop and model a high efficiency, environmentally friendly fuel cell propulsion system for electric vehicles. The costs of components and manufacturing will be reduced without loss of performance of the SPFC supplied with air instead of pure oxygen.
Significant cost reduction opportunities were identified that do not affect the performance of the fuel cells. Using Pt/Ru catalysts instead of pure Pt improved the CO tolerance of the anode by a factor of 30. Even when using air instead of oxygen on the cathode side, transport losses in the electrode can be minimised by using thin electrode structures. Membrane structures were identified which seemed to be suitable alternatives to the material currently used (NAFION). Costs modelling showed that reductions to as low as 100 ECU/kW could be achieved using these new materials, under mass production conditions.
In order that the SPFC might achieve commercial success in terrestrial application, it is necessary to reduce the costs and the amount of catalysts to be used in the fuel cell. The goal is to develop a propulsion system for electric vehicles.
The material costs of present designs of SPFC are focussed in the electrolyte membrane in the precious metal loading of the electrodes. Cost reduction will also depend on the identification of cost efficient large-scale manufacturing methods for components and stacks. The reduction of the catalyst amount in the working layer of the electrode is, therefore, yet another feature of the investigation. The catalyst loading of several mg/cm2 in presently used membrane fuel cells is too expensive and should be considerably reduced.
The experimental study will reveal the technical and commercial feasibility and specially the advantages and drawbacks of fuel cell driven vehicles as compared with the conventional propulsions. A main objective is the cost reduction by material development and replacement: inexpensive membranes, lowest possible precious metal content of the electrodes and inexpensive cooling plates.
In order to simplify the fuel preparation system reformer, the possibility of working with a CO-tolerant anode electrocatalyst will be investigated.
The component modelling will evaluate the steps of reaction occurring in the fuel cell and determine the missing physical and chemical parameters to analyze which of them are decisive for the reaction rate. At the same time, new approaches shall be made to improve the course of the reaction and the nature of transport and thus to determine the maximum current density. The results will also be used in defining the requirements for the functional and the construction materials.
From these investigations it is expected to find an answer to the question of acceptance and requirements of fuel cells with methanol as a fuel for partial markets. Also hydrogen as fuel will be discussed. The computer based modelling will lead to a definition of the optirnal working conditions, requirements for functional and construction materials, especially of the electrode structure for the utilization of feed gases containing high proportions of inactive gases (diluted reactants H2/ 2 from air).
Siemens will develop critical functional and construction materials, CO-tolerant anode catalysts, composite membranes, electrode structure and cooling plates. The reduction of catalyst loading is the primary task of AEA. They will use carbon based noble metal catalysts. A screening of radiation grafted membranes will be performed at AEA. The Centre d'Etudes Nucléaires will concentrate their efforts on anode catalysts for the oxidation of pure hydrogen. All the groups will characterize the cell performance for air operation.
Call for proposalData not available
Funding SchemeCSC - Cost-sharing contracts
OX11 0RA Didcot - Oxfordshire