There is a chart on the Ontario Ministry of Transportation that lists the 2014 Volt as having a 17kWh battery. It shows the 2012 as 16kWh and the 2013 as 16.5kWh which we know is correct. This could potentially put the EPA rating at 41 miles EV if true. If it does happen I would think they'd use the slightly larger battery in the ELR as well. Here's the link to the chart, second chart down titled Plug in Hybrid Electric Vehicles (PHEVs): Electric Vehicles
It's more likely continuing improvements in battery chemistries and costs. back at ya Speculation for the next gen Volt has them offering 2 different trims. The one closest to the current model in layout will shoot for a 50 mile AER. The other will have battery capacity and range similar to today's Volt will be able to seat 5, or least as close 5 that any compact car can get.
Battery improvements, to this date, haven't improved dramatically to lower the cost, weight, or size, to justify the 17kwh battery. More likely, larger size, weight and cost. DBCassidy
The 17kWh was a bad government form.. see 2014 Chevy Volt Battery Pack Upgraded to 17 kWh; UPDATE: Gov’t (MTO) Source Was Wrong – GM The 8% increase in EV range from 2011 to 2013 was mostly a minor change in battery chemistry and a little change in programming so here was no added weight/size/cost.
