GM has shared new details on its next-generation Chevrolet Volt that will debut at the Detroit Auto Show in January offering improved performance and increased driving range.

The carmaker would not disclose any specific numbers, but said that it will improve upon the current Volt that has a combined driving range of 380 miles (611 km) when using the 1.4L gasoline engine and 38 miles of electric/battery range.

“When it launches in the second half of 2015, it will represent a significant leap forward in technology, design and overall refinement,” GM CEO Mary Barra. “It will store more energy in its battery pack with fewer cells, yet go further on a charge. It will accelerate faster. And the car’s gas generator will come from an all-new GM engine family and use even less fuel.”

GM has replaced the previous 1.4-liter four-cylinder range-extender engine with a larger, but more fuel efficient, 1.5-liter unit that will initially be built at GM’s Toluca, Mexico engine plant for the first year of production, then shift to the Flint, Michigan engine plant.

There’s a new lithium ion battery pack with revised cell chemistry made in cooperation with LG Chem, which increases storage capacity by 20 percent on a volume basis when compared to the original cell, while the number of cells decreases from 288 to 192. It’s also 30 pounds (13 kg) lighter.

“It would have been simple for us to tweak our existing battery to provide nominally increased range, but that’s not what our customers want,” said Larry Nitz, executive director of GM Powertrain’s electrification engineering team.. “So our team created a new battery system that will exceed the performance expectations of most of our owners.”

The second generation Volt also benefits from a reengineered and re-packaged two-motor drive unit that is said to operate 5 to 12 percent more efficiently than the current system and weighs 100 pounds (45 kg) less.

“The Traction Power Inverter Module, which manages power flow between the battery and the electric drive motors, has been directly built into the drive unit to reduce mass, size and build complexity while further improving efficiency,” said GM, which added that the system will offer more than 20 percent improvement in electric acceleration.

GM said that since 2009, it has invested $1.82 billion in Michigan for projects specifically dedicated to vehicle electrification, with the new Volt’s electric drive system to be built at its Warren Transmission Plant.

“This means that all of the Volt’s major components – the battery cells, the battery pack, the electric drive unit, and the gas motor – will be made in Michigan,” said GM CEO Mary Barra.

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