Seems like an overall good report card. Other than the fact that the Model 3 is overpriced, seems like there was no big safety issues.
It is odd that Bloomberg has the power to ban the viewing of this other than on YT. Screenshot:
Not odd, they just turned off embeds.
The body is too stiff? I know that flex is part of the design, but in general cars are made as stiff as possible to improve the drive-ability.
"As [extreme in magnitude] as possible" is a thing that a lot of so-called experts get very, very wrong.
"As stiff as possible" would be making it of solid diamond. At least among currently known materials.
That would blow the budget by an astronomical margin, obviously, and also not be very strong (diamond may be hard, but single crystal material cleaves easily), and be extremely brittle (undergoes very little flex before failing catastrophically). And that, even including the assumption that a solid-diamond design would be made with heavy use of flextures to try to lend what compliance can be had!
"Possible"? Absolutely, that can be done with today's materials. But making such a gross statement completely misses the holistic, multidisciplinary truth of the matter, a truth that is real, practical, production engineering.
A much simpler version of this, and perhaps more accessible, is that of "minimize inductance" in switching power supplies. It's actually quite a bad idea indeed to attempt it, with modern materials and components. It's advice that came from the bad old days, when devices were slow enough, and boards were only 1 or 2 layers, that you were unlikely to run afoul of it.
So, really, what we are after in this case, is most likely:
once it is stiff enough for the job, any more is just added weight and cost
This is supported by his note that the body is made of far too many pieces, joints and fasteners. It may be very safe, but if none of the other players are going for a crash rating that high, there is probably a reason for it: it's not worth it.
Keep in mind, the calculus extends all the way to the life cycle of the product,
and of the customer. Remember back when Fiestas were blowing up in crashes? Management made the decision that so-and-so risk factor was an acceptable cost. Lives are worth money, both in and of themselves (a typical person in a developed country is worth something like $5M in productive economic output over their lives -- a statistic you won't see thrown about very often, nor be all too willing to give out in polite company!), and in direct impact to the company (the more important consequence: how much will they sue us for). If the risk is very well known, and small, it is perfectly rational (even if questionably ethical) to make the decision to go ahead with that risk. (In that particular example, of course, it wasn't as well known as they thought, and they screwed up badly as a result.)
As engineers and ethical actors, it is our personal duty to make a moral decision on things like this; but remember also, as a company, they are only bound by morals to the extent that it affects their bottom line. Business in general -- law in general -- is amoral, and it is usually but a happy coincidence when the two line up, not a necessity.
Back to the Tesla: probably, they wanted it at least stronger and stiffer than usual, to account for the mass and hazard of the battery. They wanted to make especially sure to avoid a Fiesta made of rocket fuel*. That would of course be pretty damning, not just to themselves, but to EVs as a whole, and to lithium battery technologies (as if swelling phones and incendiary laptops weren't bad enough already).
*Rocket fuel is the combination of fuel and oxidizer, so that combustion proceeds in the absence of any particular kind of atmosphere. Batteries meet the same description, it's just that high temperature combustion isn't their
intended mode of operation.
But this assurance came at a cost, and probably due to a number of other forces (like poor management and cost optimization), they never bothered to simplify it to the point of being as cheap as possible while still being just questionably safe enough that no one worries about it.
Tim