Okay, found this interview just published with Javier Verdura, Director of Product Design & Project Management at Tesla Motors and he's restated Elon's prior tweet a bit differently:
"Charging technology is only going to improve with time. Charging times will decrease significantly and range will increase accordingly. In the very near future, the argument that internal combustion automobiles are more convenient than electric vehicles will be a moot point. You will be able to arrive at a charging station with an empty battery and drive off with a full charge faster than you can fill up a gas tank."
Not sure we can glean anything new from it, but, it's interesting to read a new point of view from within the company (along with some great insights into working with Elon and Tesla's emphasis on design) - here is the article:
http://www.core77.com/blog/announce...with_javier_verdura_of_tesla_motors_24947.asp
Wait a second. No... Nobody is expecting a significant increase of charging speed over time. Not in the very near future, nor 100 years from now.
We're not running into battery chemistry limits here - these are physical supply-side limits we're up against. To recharge 150 miles in < 5 mins would require 540 kWh/h, which would require either a 1500 AMP supply, or a 2400 V supply.
You can't lift a 1500 AMP cable by hand, and 2400 V will arc over everything in the car. Even an intermediary mix (like 750 AMP @ 1200 V) isn't anywhere close to being practical.
Yet...
Javier is undeniably talking about advances in actual charge time. You can't interpret his statement to have anything to do with battery swapping (whether Li-Ion or Al-air) like you could do with Elon's tweet.
If there is another way to supply this that's not 1500 AMP or 2400 V, it's not foreseeable now that it will be coming in the future. So if Javier knows this is possible in a different way, they must be already sitting on the technology to do this.
Alternatively, this could be something like a robotic 1500 AMP connector (a robot arm can lift a 1500 AMP cable), that the car will drive up to and it connects "under the nose"? Certainly cheaper and easier than battery swapping.
That's assuming the current battery can handle it internally without modification, which I doubt, but at least I can see battery chemistry improving over time to handle such a rapid charge rate. I however can't see how you would ever be able to connect a 540 kWh/h cable by hand.
