Changes
* '''Electric motor''': Advanced electronics allow it to act as a motor as well as a generator. For example, when it needs to, it can draw energy from the batteries to accelerate the car. But acting as a generator, it can slow the car down and return energy to the batteries.
* '''SOC''': The State of Charge of a battery is its available capacity expressed as a percentage of its rated capacity.
== HEV battery system design parameters ==
Factors affecting battery performance:
* Temperature: Battery performance is highly dependent on temperature. Each type of battery works best within a limited range of temperatures.
* Battery age/Shelf life: Corrosion is the main culprit behind decreased performance in lead acid type batteries with age.
* Depth of discharge: Batteries are able to maintain their performance longer when they are not deeply discharged regularly.
Design parameters:
* How much space is available for the batteries?
* How much can they weigh?
* What is the desired range?
* What is the weight of the vehicle?
* What is the targeted vehicle cost?
* How will the batteries be recharged and
* What kind of drive system requirements is needed?
These are necessary questions because of the variety of battery types available and the differences between them. The chart below lists the characteristics of the most common types of batteries. (Source [http://www.atti-info.org/technology/ev_tech.html])
