Given Tesla’s recent, high-visibility reveal of its upcoming 2018 Model 3 sedan, it’s probably more than coincidence that, only days later, GM offered a glimpse into the workings of its 2017 Chevrolet Bolt EV. While the General didn’t release anything Earth-shatteringly new about the all-electric Bolt at its battery lab in Warren, Michigan, it’s clear that the Model 3 will have a formidable competitor already in the marketplace when it eventually arrives.
Insight into the Chevy Bolt’s technology has come in bits and pieces as the vehicle’s on-sale date approaches at the end of 2016, from its reveal as a concept in 2015, to a prototype drive in January, to an overview of its electric guts at this year’s Detroit auto show. It’s becoming clear that the Bolt will offer its own compelling case as a five-seat electric hatchback with at least 200 miles of range and a price of $37,500 before the government’s $7500 tax credit is applied. While the EPA has yet to certify the Bolt’s range, GM confirmed that the car’s electric drive unit (200 horsepower, 266 lb-ft of torque, 7.05:1 final drive ratio) will be enough to scoot the 3580-pound EV to 60 mph in under 7.0-seconds.
The Bolt’s 60-kWh lithium-ion battery weighs 960 pounds and is a stressed member of the car’s BEV II chassis, improving torsional rigidity by nearly 30 percent. GM says the pack was designed to last for the life of the car, that it will carry an eight-year/100,000-mile warranty, and—as with the second-generation Chevy Volt—the battery will be serviceable by dealers as necessary. Some of the pack’s accessory components have even been fitted under the front hood for easier access and maximum space efficiency. Because the underfloor battery was engineered specifically for the Bolt’s arduous duty cycle, its 288 prismatic cells have greater nickel content and will run slightly warmer than those in the Volt or the Chevy Spark EV.
However, an integrated, liquid-cooling tray—circulating 6.9 liters of Dex-Cool coolant—should keep thermal overloads at bay. The pack also has a separate heating element for warm-ups in colder climates, as well as an automatic shut-off relay integrated into its wiring for emergencies. Greg Smith, GM’s engineering group manager of electrification, says that the battery will utilize more of its available energy per charge than the Volt’s, and that throughout its development has shown minimal variation in output in extreme hot and cold temperatures. As with the Bolt’s integrated electric motor-gearbox, GM oversaw the engineering for the battery pack, but supplier LG Chem will actually produce both the battery and drivetrain in Korea before shipment to the final assembly plant in Lake Orion, Michigan. (The Warren battery plant makes packs for Chevy’s Volt, Spark EV and the Malibu Hybrid, as well as the upcoming Cadillac CT6 PHEV.)
Unlike Tesla, which has revealed few details about the Model 3’s inner workings, GM asserts that the Bolt’s battery can be fully recharged in nine hours using a 240-volt AC outlet; up to 90 miles of range can be replenished in 30 minutes using a DC quick charger. What GM wouldn’t confirm, however, was whether the front-drive Bolt will eventually be equipped to match Tesla’s Autopilot semi-autonomous technology or its optional, dual-motor, all-wheel-drive setup. But with Model 3 deliveries still far off on the EV horizon, GM has plenty of time to work on details before it faces showroom competition.
from Car and Driver Blog http://ift.tt/1oCAYHe
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