Overview

Over the 160-year history of the electric vehicle, the capability of the battery to store energy has always been the factor limiting the success of this form of propulsion. In the period 1900 1910, when electric and gasoline propulsion were competing for the burgeoning domestic and business transport market, it was the restricted range and slow refuelling of the electric car which finally resulted in the domination of the market by the internal combustion engine.

The restricted range of the electric car is caused by the limited amount of energy which can be stored in a practical battery, and this is better appreciated when it is understood that a conventional lead-acid traction battery has an energy density of about 35 Wh/kg compared to a useful energy density of more than 2000 Wh/kg for gasoline.

It should also be understood that there are many materials and chemicals which can be combined in couples to make viable primary and secondary battery cells. Because of the large number of different sources of energy that are already in use or are projected for use in electric vehicles in the future, this subject will be covered in two chapters. In this first chapter we shall only consider chemically based electric secondary storage batteries, while in the second chapter we will describe other means of storing and generating energy which can be used to power electric vehicles directly or can be used to augment battery power.

Table 5.1 lists the storage battery types which are currently...