The biggest strength of the electric vehicle industry is its diversity--lots of different models and manufacturers from which consumers can choose. A basic choice for consumers is whether to buy a battery-only electric vehicle, like the Nissan Leaf or Tesla, or a plug-in hybrid such as the Chevy Volt and Prius.
In 2011 and 2012, the plug-in hybrids dominated electric vehicle sales, but no more. In the first 6 months, of 2013, as total electric vehicle sales surged, battery only electric vehicles pulled a surprise and led the way.
See also: http://energy.gov/articles/ev-sales-skyrocketing-egallon-holds-steady.
Electric vehicles are both cheaper and fun to drive. Consumers want to drive on electricity and so plug-in hybrids are second-best options for most electric car consumers. Once all-electric vehicles extend range and decrease cost, the plug-in hybrid will sharply lose market share.