GM today unveiled an all-electric concept car, called the Bolt, which it says will have a 200-mile range. That’s comparable to the range of Tesla’s electric luxury cars, but the Bolt will cost around $30,000 (while a Tesla will sell for between $70,000 and $94,000).

The Bolt, a compact hatchback, will be launched in 2017, GM says, making it a competitor to a mid-priced, mass market car that Tesla is working on. Electric cars could be a lot more attractive to consumers if they could travel as far as gasoline vehicles can travel between refueling.

GM would not discuss anything about the battery design or chemistry that would allow the Bolt to reach a 200-mile range. Success will mean either developing an entirely new battery technology, or—more likely—greatly lowering the cost of lithium-ion batteries. LG Chem, which supplies lithium-ion batteries for GM’s existing electric-gas hybrid car, the Volt, has previously announced that it plans to supply batteries for cars with a 200-mile range.

GM started trying to develop a 200-mile range electric car in 2012, about the time it licensed what had seemed to be breakthrough technology based on research at Argonne National Laboratory, which had been further developed by the startup, Envia. Soon after, however, the Envia technology was shown to have a fatal flaw—it didn’t store as much electricity as initial tests suggested.

Tesla Motors predicts it will be able to deliver a 200-mile range, $35,000 car by 2017, in large part by scaling up production of existing battery technology.

GM also unveiled a second-generation Chevrolet Volt at the Detroit Motor Show today. The new model has a battery-only range of 50 miles instead of 38 miles in the same-size battery pack as the previous model of the Volt (the electric range is shorter than other electric cars because it’s designed to use a gasoline engine for longer trips).

The improvements to the Volt’s battery provide clues about how GM might lower the cost of lithium-ion battery technology. A GM executive says the Volt will benefit from tweaks to battery pack design and the underlying lithium-ion cell design and chemistry. The range has also been boosted by allowing owners to discharge the battery more fully between recharges.

The new Volt’s battery pack incorporates cells made by LG Chem in a factory that was, until recently, idle in Michigan (see “Too Many Battery Factories, Too Few Electric Cars”). The pack includes fewer, but larger, individual cells, and can store 18.4 kilowatt-hours of electricity, up from 17.1 kilowatt-hours. The Volt also has more horsepower, because the battery pack can discharge power at 120 kilowatts, up from 110 kilowatts.

The Volt has another new feature that contributes to the overall efficiency gain: two electric drive motors. One motor is optimized for lower speeds, such as city driving. The second motor can help at higher speeds, and for quick acceleration.

But sales of the Volt, which GM introduced in 2010, have been lower than GM projected. To date, total U.S. sales are above 73,000, but 2014 sales were 18,805, a drop of 18.6 percent from 2013. The Nissan Leaf all-electric did far better, with sales of 30,200 cars last year in the United States, up 33.6 percent from 2013. The second-generation Volt, considered a 2016 model, won’t be available until the middle of this year. Pricing has not been announced.