Fuel cells state of the art

A fuel cell is an electromechanical device that ha the ability to convent chemical energy of a reactant directly into electricity with high efficiency. When the fuel reacts with the oxidant, the electromechanical reaction takes place and some energy is released, usually low-voltage DC electrical energy and heat. The former is used to do useful work directly and the latter is wasted or can be used in cogeneration applications.
In the following sections, two concepts will be described: the unit cell and the fuel cell. The unit is the basic operating device that converts chemical energy into electricity. Multiple unit cells connected together in series make up the fuel cell, giving the desired voltage in a specific application.
Fuel cells are usually compared with other energy convertors,like reciprocating engines or batteries. In fact, batteries and fuel cells have the same operating principle, based on the electrochemical reaction between the anode, the cathode and the electrolyte. The operating principle of fuell cells and batteries will be be described in section 1.4.
The most attractive feature of the fuel cells is that they have zero emissions. Nowadays, the energy demand is becoming a great problem because it is increasing continuously. Moreover, the more energy is produced, the more the environment is contaminated. For this reason, fuel cells could be a viable solution that the issue.
This report pretends to explain the state of the art of fuel cells and the applications focused on aviation, such as unmanned aerial vehicles (UAV)