Jim Motavalli, author of “High Voltage: The Fast Track to Plug In the Auto Industry“ and contributor to The New York Times’ automobiles section, has written an excellent article about the use of carbon fiber composite material in electric vehicles.
Vehicle weight is a vital design consideration due to its direct relation to fuel efficiency and the same rule applies just as much to electric drive vehicles as it does for petrol/diesel driven motors. A lighter electric vehicle needs less energy to accelerate so manufacturers can get more mileage from the same amount of batteries or the same mileage from less batteries leading to cost reductions.
In the article, Jim Motavalli notes that the price of carbon fiber material has fallen dramatically in the last decade going from $150 per pound to just $10. However, this is still a little way of traditional steel which comes in at around $1 per pound. For electric vehicles, this extra cost is less of an issue as the extra material costs can be offset against the reduced amount of batteries used.
The article includes insight from composite specialist, SGL, as well as BMW and energy think tank, The Rocky Mountain Institute. An exert from the article can be seen below:
“The Rocky Mountain Institute, a Colorado-based energy-efficiency think tank, has long championed the use of composites like carbon fiber to create super-green “hypercars.” According to the group, “With drastically lighter platforms, propulsion systems can be smaller, lighter, cheaper, more efficient and, ultimately, more cost-effectively electrified.”
The latter point is critical, because batteries are very expensive, too. Dave Buchko, a BMW spokesman, says that the company chose to make its i3 body shell out of carbon fiber because “we won’t need as many battery cells to reach our target 100-mile range. Our solution balances the right weight with battery capacity.”
Greg Rucks, a Rocky Mountain Institute consultant, says that carbon fiber has some built-in cost savings, because there are fewer assembly steps (and fewer rivets) with the material, and the lighter weight means that suspension, brakes and other components can be downsized.”
Read the full article at TXCHNOLOGIST