The race to develop and volume-produce a battery-electric vehicle that is capable of at least 200 mi (322 km) driving range and is priced at $30,000 (after incentives) has intensified, with General Motors confirming on February 12 that it will produce its Chevrolet Bolt EV. Unveiled as a concept at the 2015 North American International Auto Show, the Bolt EV will be built at GM’s Orion Assembly plant north of Detroit.
The five-door electric is expected to arrive as a 2017 model, according to suppliers familiar with the project’s timeline, although GM has not officially stated the car’s start-of-production timing. “We’re applying our EV expertise to take electrification further,” said GM CEO Mary Barra during the NAIAS. The Bolt will be sold in all 50 U.S. states as well as many global markets.
The car’s liquid-cooled lithium-ion battery technology "is in the progression of what we’ve revealed about the 2016 Volt battery,” according to Pete Savagian, GM’s General Director of Electrification Systems, who spoke briefly with Automotive Engineering during the Bolt’s Detroit show debut. While he provided no further details about the Bolt’s energy-storage and propulsion systems, it’s worth noting that the new Gen-2 Volt uses prismatic-pouch-type cells with a NMC/LMO (Nickel Manganese Cobalt/Lithium Manganese Oxide) chemistry. This enabled a 20% improvement in volumetric energy density. The 2016 Volt’s cells are supplied by LG Chem (see http://articles.sae.org/13666/); no word yet on the Bolt’s battery-cell supplier.
The concept’s exterior form, with its short front and rear overhangs, is “very close” to the production car but the concept interior “is being extensively reworked for production,” said a GM engineering source who asked to remain anonymous. GM engineers are putting a major effort into reducing mass in the Bolt’s structure to offset the battery weight; the concept was said to weigh 3543 lb (1607 kg). The production car will use a mixed-materials strategy consisting mainly of high-strength steel and aluminum alloys, with magnesium and (perhaps) carbon fiber used in specific areas.
If GM actually brings the Bolt to market at $30,000 by 2017, it could be the first EV manufacturer to achieve the feat of combining such a relatively low MSRP with at least 200-mi electric operating range. Tesla CEO Elon Musk has stated that his company’s upcoming Model 3, designed for similar range, will enter the market in the 2017 time frame at $35,000 after incentives, Musk said.
By comparison the 2015 Ford Focus EV’s base price is also about $30,000 but its 23 kW·h liquid-cooled lithium-ion battery pack delivers a range of 76 mi (122 km) according to the U.S. EPA. Two B-segment EVs priced about $12,000 higher, the BMW i3 and Mercedes B-Class Electric Drive, carry window stickers showing driving ranges of 81 and 85 mi (130 and 137 km), respectively. The BMW’s battery pack is rated at 22 kW·h, while the Mercedes’ pack is rated at 36 kW·h. The Mercedes is capable of delivering slightly more than 100 mi (161 km) range in ideal thermal conditions.
Bolt’s powertrain controller will allow drivers to select operating modes based on preferred driving styles in various operating conditions such as commuting and steady-state cruising. In the concept vehicle, the modes adjust accelerator pedal mapping, vehicle ride height, and suspension tuning. The car also is expected to be capable of dc fast charging.
The concept also featured a dedicated app that enables various functions, including self-parking, to be accessed via smartphone.
To support Bolt production, GM has invested $200 million in the Orion Assembly and nearby Pontiac (MI) stamping plant, with $160 million going to Orion for tooling and equipment and $40 million to Pontiac for dies. The Orion plant is powered by natural gas that is piped in from two nearby landfills. It also uses a 350-kW solar-panel array to generate electricity for use in the plant; excess off-peak energy is sold back to the local power grid.Continue reading »