Hybrid cars, electric vehicles, EV and HV.

Hybrid cars, electric vehicle, EV and HV.

Download free pdf books on EV (electric cars) HV (hybrid cars)

Hybrid cars technology

A hybrid car combines two methods for the propulsion of a vehicle. Possible combinations include diesel/electric, gasoline/flywheel, and fuel cell/battery. Typically, one energy source is storage, and the other is the conversion of fuel to energy. The combination of two power sources may support two separate propulsion systems.

 What are fuel cells? Broadly speaking, a fuel cell is an electrochemical reactor that converts the chemical energy of a fuel and an oxidant directly to electricity. More recently, the word fuel cell has been used almost exclusively to describe such a reactor using hydrogen as the primary source of energy. Hydrogen has a long history of being used as fuel for mobility.

More than 200 years ago, hydrogen was used in the very first internal combustion engines by burning the hydrogen itself, similar to burning gasoline today.

However, this did not prove to be quite successful, due to safety concerns as well as low energy density. Rather, in a modern fuel cell, hydrogen is a carrier of energy, by reacting with oxygen to form electricity.

The reaction between hydrogen and oxygen  in a fuel cell

The reaction between hydrogen and oxygen is astoundingly simple, and can be represented by the following formula: 2H2 +O2 =2H2 O. 5 In a fuel cell, hydrogen and oxygen are introduced separately with hydrogen supplied to one electrode of the fuel cell and oxygen to the other. The two electrodes are separated by a material called the electrolyte, which acts as a filter to both stops the cell reactants from mixing directly with one another and to control how the charged ions created during the partial cell reactions are allowed to reach each other. Hydrogen molecules first enter the hydrogen electrode (called the anode) of the fuel cell.

The hydrogen molecules then react with the catalyst coating the anode, releasing electrons to form a positively charged hydrogen ion. These ions cross the electrolyte and reach the oxygen at the second electrode (called the cathode). The electrons, however, cannot pass the electrolyte. Instead, they flow into an electrical circuit, generating the power of the fuel cell system. At the cathode, the catalyst causes the hydrogen ions and electrons to bond with oxygen from the air to form water vapor, which is the only byproduct of the process.