Beth: Rolls-Royce seemed more interested in making sure the battery fit in the existing engine bay, so they wouldn't have to re-design the vehicle. Their use of a 240 Wh/kg battery is key there. With a lower energy density (140 Wh/kg is more typical today), the battery would hav been much bigger and heavier.
I find the point that the battery for the Phantom could cost between $35,000 and $70,000 mind boggling. Just goes to show you what luxury can afford. Any sense of what kind of special considerations Rolls Royce's performance and quiet requirements have in terms of EV development?
Ivan: Most automakers (Rolls-Royce included) don't want to talk about the price of electric car batteries, so this is a very slippery subject. Often, you'll hear estimates of about $500 to $600/kWh but these are typically given without including the price of the cooling and electronic control system. The National Academy of Engineering estimated that total EV battery cost is more than $1,000/kWh. Toyota said the same in 2010. Tesla and Nissan have said their cost is $500/kWh, but, again, this is believed to be the price for the cells, not the entire system. I talked to Pike Research this morning, and they said they are inclined to believe that EV batteries typically cost $800 - $1,000/kWh. To be fair, I think it's best to give a price for the entire system, since cooling is an absolute requirement for lithium-ion battery chemistries. If you really want to pin it down, I think Pike's number is as good as you'll get.
There are a couple of interesting points and facts in this article. The 120 mile range is better than most other cars. The "range anxiety" issue remains though even if the driver does not need it or expect to use it.
The battery pack is indeed large, heavy and expensive. 5 modules, at 1400 lbs is a big piece of the weight margin for the car. The cost per KwH is stated as $500 to $1K. I would like to see this pinned down a bit more.
The battery chemistry is stated to be Lithium-nickel-cobalt-manganese etc..... so one would think the advances in lithium chemistry are finding their way into new designs.
Th limitations still appear to center around the battery packs' energy density and cost. It would seem that a doubling of the energy density and reducing the cost by half or better is going to be necessary to make the design truly useful and get it into the mainstream.
Festo's BionicKangaroo combines pneumatic and electrical drive technology, plus very precise controls and condition monitoring. Like a real kangaroo, the BionicKangaroo robot harvests the kinetic energy of each takeoff and immediately uses it to power the next jump.
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