Famous electric car firm Tesla Motors, which has now delivered over a thousand li-ion powered $100k Roadster sportscars, has had a successful IPO. The company's stock, after a slight initial dip, climbed by 40 per cent during its first day listed on the NASDAQ exchange. Initially priced at $17, Tesla stock closed at $23.89, …
Back to front
Rather than propping up individual manufacturers or their products, governments should be investing in the network of battery swapping stations that would be necessary to make the tech viable for most and mass market.
I really like the Model S - I think it's the closest thing I've seen to an electric car I could see myself buying - but it needs to be either extremely fast charging or battery swappable, and supported by an appropriate infrastructure - until then it's just an expensive toy for rich people who are travelling for fun rather than necessity.
re: Back to front
Battery swapping stations etc are not going to appear overnight and until they do the pure electric car just won't be practical for everyday use.
Thats not to mention that for power to weight chemical fuel is far better than battery storage - electric motors are lightweight but batteries are very heavy. Hybrid technology makes a lot more sense to me.
A customer swappable battery pack for *any* EV would be a good accessory
Not sure how *practical* it is in the Roadster's case but people have them for their cell phones and I guess ones that can be charged when *not* connected to their laptop exist (at least for some models).
Thumbs up for a fairly decent IPO. Perhaps Tesla could be the Porsche of the 21st century.
Now if only they could be cheaper.
An accessory that, unfortunately, costs about as much as a brand-new pickup truck.
Back of the envelope/discarded printout.
The biggest problem this thing has is battery power.
I think an issue of EE times once claimed that gasoline has eighty times the energy density of a good lithium-ion battery. When I worked it out on paper (comparing gasoline, at 32 MJ/L and about 0.72 kg/L) to the Tesla Roadster's battery (190.8MJ at 450kg), I get that gasoline is about a hundred times better; however, much of the mass of the Roadster's battery pack is wiring and other materials, so that number has to be high.
Let's be generous, then, and say that (a) Lithium-ion battery technology has gotten a lot better and that (b) only half the mass of the battery pack is batteries. A stretch, but a good upper limit to energy density: Gasoline is somewhere north of fifty times the energy density of lithium ion batteries. So here I've derived the obvious: The best electric car battery on the market has terrible energy density.
(My gas tank holds 17 US liquid gallons, which is about 64.3 liters. I get a little over two 2GJ assuming 32MJ/L. This is about ten times the energy that the Tesla's battery pack holds, and weighs a tenth as much when full.)
The cost per megajoule of gasoline and of electricity at residential rates where I live are about the same. I went to my local electric cooperative's website and found that they're charging a residential rate of $0.0925/kWh, or a little over $0.025/MJ. By comparison, gasoline here currently costs about $2.70 per gallon, which is about $0.022/MJ--slightly less. However, the electric motors Tesla uses are, the company claims, something like 85-92 percent efficient, which is a lot more than any present-day gasoline engine* can manage.
So, as it stands, gasoline has vastly superior energy density, far more energy fits in your car at once, the cost per unit energy is currently about the same, and a gasoline-powered car doesn't lose any appreciable energy capacity over time unless somebody poked a hole in the tank, whereas batteries have to be replaced (at least $20,000 for a new Tesla battery pack, assuming that Tesla has worked out some awesome deal where they get lithium-ion cells at less than wholesale price) every few years. The battery is the biggest impediment to electric cars, and always has been. Electric car designs date back to the 19th century, and in that entire history, Tesla is probably the closest thing to a commercially successful product--and it's still lost over $200 million. The saving grace here is the efficiency of the electric motors (whose design Tesla has catered to the purpose). Then again, some of that gain will probably go away by having 450kg of battery sitting in your car. I guess there's also the additional incentive of feeling "environmentally friendly", which appears to be something for which people will pay a lot of money* (when they are not thinking about the disposal process of a 450kg lithium-ion battery that has to be replaced every few years, anyway.)
*Especially since the emissions regulations craze of the 1980s. Before that, it was not uncommon to see cheap consumer cars being sold that beat forty miles per gallon. Mind you, these were still somewhere well south of a third Tesla's claimed efficiency.
**Look at how much a Prius costs. If you want low TCO, buy a Jeep or something.
Do they make expensive toys for poor people?
"... an expensive toy for rich people ..."
A fun calcucaltion
Is to take the volume of a battery and its known capacity and work out how much of that volume equals the number of electrons it can release presuming an electron is a cube 1x10^-10m on a side.
It is *minuscule*, as in <0.1% of volume.
There is a *lot* of room left for improving the volumetric storage efficiency of a battery.
Weather Li ion or some other technology can deliver that improvement (basically I'm thinking 1 electron for *every* molecule of donor molecule in the structure).
- JLaw, Kate Upton exposed in celeb nude pics hack
- Google flushes out users of old browsers by serving up CLUNKY, AGED version of search
- GCHQ protesters stick it to British spooks ... by drinking urine
- China: You, Microsoft. Office-Windows 'compatibility'. You have 20 days to explain
- Something for the Weekend, Sir? If you think 3D printing is just firing blanks, just you wait