With batteries, you get energy density or power density, but not both; high power density cells are not only more expensive, but less energy dense.
Nonsense alert - while energy density is a well-defined, meaningful metric, power density is at best a poorly defined one and at worst a meaningless juxtaposition of words, a.k.a. marketing. It certainly does not make sense to talk about both of them together this way. One of them is a physical metric, the other is ... not. Otoh, if he were talking about power, that would have been a different kettle of fish altogether.
And you can up the power density just by adding more cells.
Sorry Rei, but this shows your bullshit detector is out of whack. If it's [something] density then the total amount of volume (or in this case, cells) is irrelevant, since density is [something] per unit volume (or per cell). So the statement is wrong as is, would be "right-er" for power, but then it's not just cells that you have to add, is it? more power requires higher amperage wiring, better cooling, and so on - it's not just about stuffing the car to the gills with batteries.
And lastly, for the record: despite how this Slashdot summary makes it sound, despite the short-selling surge, Tesla's stock has already recovered 2/3rds of the drop after the call. And I can't think of anything dumber than shorting a stock because you thought the CEO was rude during a call (despite the company beating its whisper number, the number that the stock was valued based on, immediately beforehand). I mean, seriously, you're going to drop the stock nearly 10% because you thought the CEO was rude? Get over your personal obsession with the guy.
:-( this post started so well, factual and stuff. Please, next time, try to refrain from repeating something like this last paragraph. If you really have to, make a separate post. There are so many things wrong in this small ending that it'd take a full post to explain - stuff about how stock market works, about sending messages, especially during conference calls, and lastly about irony and seeing emotions in others while being blind to them in oneself. I am aware of your history of posting pro-Musk things on /. but for the sake of efficiency do try to keep informative posts separated from "opinion" posts. It makes for better reading.