{"id":9703,"date":"2015-03-09T00:04:02","date_gmt":"2015-03-09T07:04:02","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=9703"},"modified":"2015-03-09T00:04:02","modified_gmt":"2015-03-09T07:04:02","slug":"audis-r8-e-tron-possibly-doubles-battery-energy-density","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/audis-r8-e-tron-possibly-doubles-battery-energy-density\/","title":{"rendered":"Audi\u2019s R8 e-tron Possibly Doubles Battery Energy Density"},"content":{"rendered":"

Autoblog.com<\/em> provides an early view of Audi’s newest electric supercar<\/a> and material from Audi’s press release regarding the vehicle. \u00a0Although much positive PR has been generated about the car’s new battery and its improved energy density, closer examination shows it’s about what we might expect, and close to what Tesla already offers.<\/p>\n

Audi\u2019s latest iteration of its R8 e-tron uses a \u201cmultimaterial Audi Space Frame,\u201d variable geometry wheels which open and close to ventilate and streamline, and a battery pack which occupies the same space as the earlier model\u2019s but which has twice the energy storage capacity.<\/p>\n

The space frame includes a carbon fiber reinforced plastic (CFRP) rear-section module which comprises the luggage compartment, but also provides rear crash protection through corrugated walls.\u00a0 This may also be a way to maintain security for the battery pack, which forms a \u201cT\u201d with the top bar forming a high wall behind the car\u2019s two seats. \u00a0Battery modules stacked four-high might form a structural element, but need to be protected themselves.<\/p>\n

\"Audi<\/a>

Audi R8 e-tron’s structurally-integrated battery has “T” forming wall behind passenger cell<\/p><\/div>\n

The battery pack, which could store 49 kilowatt-hours in its original chemistry, has been developed to store 92 kWh in the latest version (the largest Tesla pack is 85 kWh) \u2013 at no increase in weight.\u00a0 Energy density has increased from 84 Watt-hours per kilogram to 154 Wh\/kg.\u00a0 An on-board Combined Charging System (CCS) allows charging \u201cwith direct and alternating current\u201d in \u201csignificantly less than two hours.\u201d\u00a0 The improved battery pack more than doubles the previous version\u2019s 215 kilometer (133.6 mile) range to 450 kilometers (279.6 miles), putting the car in Tesla S territory.<\/p>\n

The impressive part is the doubling of energy density, however, with a total package weight, including battery management systems, charging gear, and ancillaries certainly competitive with almost any other electric vehicle.\u00a0 Audi is quiet about their proprietary chemistry, referring to it only as lithium-ion. \u00a0 Tesla’s 85 kWh pack, for instance, weighs 1,323 pounds, or around 155 Watt-hours per kilogram. \u00a0Contrarily, much is being made of Audi’s doubled energy density, when the original’s batteries were based on at least six-year-old technology. \u00a0Dr. Yi Cui’s projection of an eight-percent improvement each year would come close to approximating this progress. \u00a0It would lead one to suspect that this is close to the best one can hope for with today’s best and very expensive technology.<\/p>\n

Two 170 kilowatt (228 horsepower) motors provide 460 Newton meters (340 foot-pounds) of torque each, enabling 0-100 kilometers per hour (62.1 mph) in 3.9 seconds.\u00a0 Its top speed is electronically limited to either 210 km\/h (130.5 mph) or 250 km\/h (155.3 mph).\u00a0 Regenerative braking and related systems manage \u201chigh energy recuperation rates.\u201d<\/p>\n

\"Audi's<\/a>

Audi’s neatly done alternative production line integrates electric drive train into mostly same chassis used in V-10 internal combustion version<\/p><\/div>\n

Audi uses the order-built e-trons as a development tool, and may be putting lessons learned into a sedan that might give the Model S some competition.\u00a0 Pricing will be high, though, with insiders suggesting $250,000 for each custom-built model.\u00a0 The good news is that battery pack, though, with much smaller packs that might be used in light aircraft benefiting from the high energy density.<\/p>\n

Competition does improve the breed, and sometimes provides benefits for adjacent technologies.<\/p>\n