The reaction mechanism of a fuel cell is to convert the chemical energy in the fuel directly into electrical energy without combustion. That is, to convert chemical energy into electrical energy through an electrochemical reaction. In fact, it is the reverse process of water electrolysis, in which water is generated and electrical energy is released through the chemical reaction of hydrogen and oxygen.
Fuel cell reactions do not involve a heat engine process, therefore their energy conversion efficiency is not limited by the Carnot cycle and is highly efficient; its emissions are mainly water, which is very clean and does not produce any harmful substances. Therefore, the research and development of fuel cell technology has received significant attention from governments and large corporations worldwide, and it is considered one of the cleanest and most efficient power generation technologies of the 21st century.
Main structure of fuel cell electric vehicles
Pure fuel cell vehicles rely solely on the fuel cell as their power source, with all of the vehicle's power supplied by it. Fuel cell vehicles often employ a hybrid drive system, adding another battery or supercapacitor as a secondary power source to the fuel cell. The basic components of a fuel cell include electrodes, an electrolyte, fuel, and an oxidant. Fuel can be hydrogen (H2), methane (CH4), methanol (CH3OH), etc., the oxidant is typically oxygen or air, and the electrolyte can be an acid/alkali solution (H2SO4, H3PO4, NaOH, etc.), molten salt (NaCO3, K2CO3), solid polymer, solid oxide, etc. Unlike conventional batteries, fuel cells can continuously generate electricity as long as the supply of fuel and oxidant is guaranteed.
Components of a fuel cell electric vehicle
1. Fuel Cell Engine (FCE): Primarily composed of a fuel cell stack, air intake system, drainage system, hydrogen supply system, cooling system, stack control unit, and monitoring system. This is the main power source.
2. Power battery pack: auxiliary power source.
3. Current converter: AC to DC conversion.
4. Powertrain: Transmits power and shifts gears.
5. Hydrogen system: Provides hydrogen.
6. Power control unit: power control and fault diagnosis.
In addition to facing the same problems as electric vehicles in terms of body, controller and drive system, fuel cell electric vehicles also have many problems to be solved in terms of their energy storage power source - fuel cells. The technology of hydrogen fuel cells in terms of hydrogen fuel production, storage and carrying, as well as the efficiency, size, mass and reaction speed of non-hydrogen fuel cell reforming systems, still needs to be further improved.
