The Chevrolet Spark EV has been on the market for only a year, but already it's being updated.

And in this case, the update is major: The 2015 Chevy Spark EV will have an entirely new battery pack.

Battery pack assembly for 2015 Chevrolet Spark EV electric car at GM's Brownstown, Michigan, plant

Battery pack assembly for 2015 Chevrolet Spark EV electric car at GM's Brownstown, Michigan, plant

General Motors announced yesterday that it will bring assembly of the electric Spark's battery in-house and assemble packs for the 2015 Spark EV at the Brownstown, Michigan, plant that already builds batteries for the Chevrolet Volt, Opel/Vauxhall Ampera, and Cadillac ELR.

DON'T MISS: 2016 Chevrolet Volt To Launch Next Year: What We Know So Far

Batteries for 1,000 or so Spark EVs for the 2014 model year were assembled by Compact Power Inc. at a different Michigan plant, then shipped to South Korea for installation in the electric version of the Spark minicar.

Battery pack assembly for 2015 Chevrolet Spark EV electric car at GM's Brownstown, Michigan, plant

Battery pack assembly for 2015 Chevrolet Spark EV electric car at GM's Brownstown, Michigan, plant

The new battery for 2015 will use different lithium-ion cells, switching from those provided by A123 Systems to cells from LG Chem--the company that makes cells for the much higher-volume Volt and also the ELR.

ALSO SEE: First 2014 Chevy Spark EV Sold: Why We Chose This Electric Car

The energy capacity of the battery will fall from 20 to 19 kilowatt-hours, but GM says the 2015 Spark EV's EPA ratings for range (82 miles) and efficiency (119 MPGe) will remain unchanged from the previous model.

The new battery using LG Chem cells is 86 pounds lighter than the old one with A123 cells, meaning it is both lighter and more efficient than the earlier pack.

Centralizing all its battery assembly and standardizing on a single lithium-ion cell for its electric cars makes sense as GM strives to expand its plug-in vehicle activities and prepares to unveil an updated version of the Chevrolet Volt range-extended electric car for the 2016 model year.

The change "helps us to better leverage our economies of scale," said GM's executive director of global transmission and electrification engineering, Larry Nitz.

Battery pack assembly for 2015 Chevrolet Spark EV electric car at GM's Brownstown, Michigan, plant

Battery pack assembly for 2015 Chevrolet Spark EV electric car at GM's Brownstown, Michigan, plant

It remains unclear if bringing the pack assembly in-house--the Spark EV's electric motor is already built by GM in a plant in White Marsh Sands, Maryland--will permit the company to boost production of its littlest electric car.

MORE: GM Now Building Chevy Spark EV Electric-Car Motors In Maryland

The Spark EV is largely viewed as a compliance car, one sold only in California and a handful of other locations, and in numbers only sufficient to meet the state's zero-emission vehicle sales requirements.

The 2014 Chevy Spark EV received enthusiastic reviews when it launched, with reviewers lauding its performance--100 kilowatts (130 horsepower) of peak power to the front wheels, far more than the gasoline version of the Spark minicar--and its Volt-like instrument graphics and interface.

The 2015 Chevrolet Spark EV remains priced at $27,495 before any Federal and state incentives. It is now on sale in California and Oregon.

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