TABLE OF CONTENTS This chapter contains three sections. The first section briefly describes the application of fuel-cell systems as self-standing energy sources for powertrains or in combination with a storage system as fuel-cell hybrid powertrains. The second section introduces some thermodynamic and electrochemical models of fuel cells, as well as some fluid dynamic models of the complete fuel-cell system. The last section introduces the on-board production of hydrogen through fuel reforming and presents some system-level models of methanol reformers.
The main objective of this chapter is to introduce models that are useful in the context of energy management. Readers interested in the low-level control of fuel-cell systems are referred to [172].
Fuel cells are electrochemical devices that convert chemical energy directly into useful electrical energy. In contrast to internal combustion engines, there is no intermediate conversion into thermal energy and from that to mechanical energy. The efficiency of a fuel cell is thus not limited by the Carnot efficiency, and it can reach in principle more than 100% based on the lower heating value of the fuel.
Fuel cells deliver electrical energy, i.e., pure exergy, without any combustion products. This is the reason why, along with purely electric vehicles, fuel-cell vehicles are classified as zero-emission vehicles. As shown in Chap. 1, the specific energy of hydrogen as a substance is substantially better than that of electrochemical batteries. Therefore, fuel-cell vehicles seem to be able to combine the best features of EVs and of ICE-based...
