Recharging Electric Vehicles

Consumers may have a vague idea that recharging EV batteries entails connecting the car to an electrical outlet. However, EV recharging can be a bit more complicated than the recharging associated with consumer gadgets such as computers and cell phones.

First, consider the batteries. Improvements in battery technology moved automobile makers to adopt the energy dense Lithium ion (or Li-ion) batteries for their vehicles.

Perhaps battery pack or battery module offers a more accurate description of the EV energy source. In order to store sufficient energy to run an EV, it needs a group of connected batteries. The Chevrolet Volt, for example, advertises that its battery consists of two hundred cells.

Recharging such a large battery pack presents some practical challenges. While EV manufacturers advertise that their batteries can be recharged using a run of the mill 120V household outlet, they also either implicitly or explicitly promote the use of a stand alone 240V charging station.

Charging time represents the major difference between using a 120V and 240V outlet. Consider, for example, the real world recharging times advertised for the Chevrolet Volt and the Nissan Leaf.

Volt's approximately forty mile range translates into a battery pack recharge time of eight hours using a 120V household electric outlet, and less than four hours using a 240V outlet.

Recharging the battery pack for the Leaf's approximately one hundred mile range means an eighteen hour wait using a 120V household outlet and an eight hour wait (overnight charging) on a separate 240V outlet.

Of course, taking a cross-country trip, or any extended road trip using a limited range EV would be spoiled by long hour recharging times.

The Volt partially solves the problem by adding a separate gasoline engine to extend its range. Notwithstanding the adoption of a dual technology option, converting EVs into the practical transportation of the future means building a recharging infrastructure across the country.

Currently a public-private partnership called ChargePoint America is focusing on building the EV recharging infrastructure in nine metropolitan areas considered as the initial EV markets.

These stations operate using the 120V and 240V standards, making recharge time problematic for individuals in a hurry. Plans for a faster charging 480V outlet are on the table.

Battery swap outlets, where EV drivers come in and swap their depleted battery pack for a fully charged pack, are also on the drawing board.

With respect to the recharging issue, the first wave of EVs promises to provide consumers with a viable, gasoline free, short commute option as part of a two car household strategy. Continued improvements in battery technology, coupled with the existence of a recharging infrastructure as mature as the ubiquitous gas station will transform the EV from the car of tomorrow to the car of today.

© 2010 Patricia A. Michaels