Fuel Cell and Hydrogen Vehicles - State of the Art and Challenges for improved Materials

Abstract

Fuel cell vehicles should be further improved regarding key operation parameters like operation temperature and starting ability in freezing conditions. Additionally higher power densities, less complex system concepts and cost reduction are required. For customer acceptance it is important to achieve higher ranges with hydrogen vehicles. Therefore, improved materials are the base for progress of fuel cell and hydrogen vehicles. Within a fuel cell vehicle the core component fuel cell stack determines the operation conditions as well as the complexity of the system. Within the presentation an overview about fuel cell stack technology is given focusing on the polymer electrolyte fuel cell, which is mainly considered for vehicle application. Progress in stack components is described. Examples for stack components are the polymer membrane and the bipolar plates. In the second part of the presentation an overview about on-board hydrogen storages is given. There are basically three options to store hydrogen: compressed in a pressure tank (up to 700 bar), cooled to liquid state and kept at low temperatures (20 K) in an insulated tank and storage of using an hydrogen carrier, e.g. a solid compound like a metal hydride. Pressure tanks and liquid hydrogen storage made great progress. However, cost reduction and concepts, which utilize the available space at its best, are requested. Hydrogen storage in solid compounds is still in the research stage, whereby e.g. alanates gain more attention. Regarding solid compounds the paper reflects also system integration aspects.