The second-generation Chevrolet Volt is important not only as a high-volume plug-in hybrid, but also because components from its Voltec powertrain are designed to be used in other GM models.
Last year, General Motors unveiled the 2016 Chevrolet Malibu Hybrid, with a powertrain very similar to the Volt's.
Around the same time, it also unveiled the Cadillac CT6 Plug-In Hybrid.
It's been assumed that this plug-in version of Cadillac's new large sedan would also borrow heavily from the Volt.
And now that we have full technical details on the CT6 powertrain, Cadillac has confirmed that it uses quite a few components from the Chevy—but with many changes dictated by its rear-wheel drive platform and sportier bent.
Tim Grewe, GM general director of electrification, and Pete Savagian, the carmaker's general director of electric drives and systems engineering, detailed the CT6 Plug-In Hybrid powertrain at the SAE Hybrid and Electric Vehicle Technologies Symposium last month. Green Car Congress published a report on their presentation.
The powertrain consists of a 2.0-liter turbocharged four-cylinder gasoline engine, two electric motors, and an 18.4-kilowatt-hour lithium-ion battery pack—the same capacity as the Volt's pack.
Total system output is 335 horsepower, GM says, enough to get the CT6 Plug-In Hybrid from 0 to 62 mph in 5.6 seconds.
GM also claims an electric-only range of about 37 miles, although official EPA range and efficiency figures haven't been published yet.
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Rather than the T-shape used in the Volt, which places the pack in the tunnel between the front seats and under the rear seats, the CT6 pack is integrated into the floor.
A press release from the CT6 Plug-In Hybrid's unveiling at the 2015 Shanghai Motor Show last year said it was located "between the rear seat and trunk."
The battery-pack tray actually acts as the main floor structure, increasing stiffness, GM's Grewe said.
2017 Cadillac CT6 Plug-In Hybrid
A separate tray holds all of the "modules" that are common with the Volt, including common electronics and the battery-state estimator.
The two-motor drive system is also essentially the same as the Volt's, but with an additional planetary gearset (for a total of three) and two more clutches (making five).
"Basically, that gives you a Volt on steroids," Grewe said.
He said the CT6 Plug-In Hybrid will have the same "EV launch feel" as the Volt, with instant torque from the electric motors used to maximum effect.
The CT6 also uses two types of electric motors. One is an induction motor, while the other is a permanent-magnet design.
The motor closest to the engine is the induction-motor, a design chosen by GM because it does not require rare-earth minerals.
2016 Cadillac CT6
The second motor is similar to the one used in the Chevrolet Spark EV, but is somewhat longer.
This motor will also be manufactured at the same plant that builds Spark EV motors—GM's facility in White Marsh, Maryland.
And the battery pack will be assembled in GM's battery plant in Brownstown, Michigan, using LG Chem cells fabricated across the state in its plant in Holland, Michigan.
But the CT6 Plug-In Hybrid itself will be assembled in China, and imported to the U.S.
That will make the plug-in hybrid model the first Cadillac imported for sale in the U.S., and one of a small but growing handful of U.S.-market cars built in China.
It's expected to arrive here late this year or early next year.