2.5.- STORAGE BATTERIES

Electricity can be generated trough the energy stored in certain chemical compounds and kept in reversible electrochemical devices called batteries, which are groups of small hermetic cells that can provide DC current in an electric circuit.

In the BEV, those batteries are installed in the vehicle in a similar way to the fuel tank in ICVs, but with a relevant difference in the power storage capacity: while internal combustion cars can achieve an operative autonomy of between 500 and 1000 km, the average commercial electric vehicle offers no more than between 100 and 300 km with one charge.

The proprieties that make a battery attractive for its use in the BEV are:

• High energy content per weight (kWh/kg) and volume (kWh/L), in order to achieve the maximum autonomy possible (300 km per charge would be satisfactory for most of the consumers).

• Maximum potency per weight (W/kg) as possible, which means more acceleration capability in the road.

• High lifespan (maximum tolerable recharges before losing capacity).

• Low building/achieving cost per energy unit ($/kWh). Batteries are a very expensive part of the BEV, and usually have a notably low lifespan.

• Minimum toxicity as possible, considering that most of cells are made in harmful elements (i.e. acids or heavy metals, depending on their nature).