The Chevrolet Volt used only half its battery so the battery would last
Engineers at General Motors gave the first Volt a 16 kWh battery and then deliberately locked away half of it, never charging above 80% or draining below 30%. The sacrifice was meant to keep the pack healthy for 10 years and 150,000 miles, and by August 2016 GM said no battery had needed replacing for wear.
The Volt was an electric car carrying a gasoline generator. It ran on battery power until the charge fell to a set level, then a small engine spun a generator to keep going; at high speed a clutch could link the engine to the gearbox, gaining 10% to 15% in efficiency. The 2013 to 2015 models managed 38 miles on electricity alone, and the second generation, delivered from October 2015, stretched that to 53.
Choosing the battery took a global search. GM weighed about 25 cell designs from roughly two dozen makers before shortlisting Compact Power, backed by LG Chem, and a partnership using A123Systems cells in June 2007, finally picking LG Chem in October 2008. Test packs were rattled on a shaker table imitating potholes and cycled between desert heat of 116 °F and Alaskan cold of −40 °F, while prototype drivetrains rode around inside Chevrolet Malibus.
Aerodynamics reshaped the concept: its drag coefficient of 0.43 had to fall to 0.28 for production, and the T-shaped battery running through a raised central tunnel cut seating from five to four. The first retail Volt went to GM's Heritage Center museum, and the second, auctioned for charity from an opening bid of US$50,000, sold to Rick Hendrick for US$225,000, with the money funding science and maths teaching in Detroit schools.
Sales started in the United States in December 2010, with rebadged versions sold as the Opel and Vauxhall Ampera, Holden Volt and Buick Velite 5. The family was the world's bestselling plug-in hybrid until December 2018, and the United States took 157,054 Volts before production ended in February 2019.
Source: Chevrolet Volt
