About electric drive technology - introduction to electric drive

What is 'electric drive'? We are using the umbrella term to embrace hybrids (mild and full), plug-in hybrids, extended-range electric vehicles (E-REVs) and pure battery electric vehicles (or BEVs). These categories of vehicle have in common the exploitation of electrical energy to drive vehicle wheels for propulsion, though hybrids (and E-REVs if the gasoline engine kicks in on a long journey) achieve that in collaboration with the burning of fossil-fuels.

In fact, the label ‘hybrid’ is frequently applied to everything from start-stop systems to extended-range electric vehicles. And journalists who should know better – let alone industry analysts and executives at some OEMs – seem to show precious little understanding of the fundamental differences between a conventional parallel hybrid with a larger battery pack that can be recharged from the mains (e.g. 2012 Toyota Prius plug-in hybrid) and a series hybrid or E-REV (e.g. 2011 Chevrolet Volt) than runs purely on electric power, whether or not the combustion engine is switched on.

Many industry analysts see hybrids as a compromise or ‘bridging’ technology reflecting the current limitations (especially limited vehicle range on power discharge) associated with battery technologies. They wouldn’t be necessary, the argument goes, if pure EVs could deliver better performance and didn’t come with ‘range anxiety’. That may well be the case, but the ‘transition period’ ahead could be a long one given the rate of industry progress in improving battery performance and ongoing efficiency improvements to fossil-fuel burning powertrain technologies and low-carbon innovations such as the use of ‘second generation’ biofuels. Much hinges on future powertrain technology advances, the political environment (government incentives, climate change sensitivity) and, of course, the price of oil.