"Isn't this megauberhypersuperduper-charging a bit dangerous?"
About as dangerous as fuelling with diesel or gasoline. The energy tranferred to the vehicle and power flux are actually larger in petroleum fuelling because of the superior efficiency of electric drivetrains.
Not quite.
If you have a look at the
how stuff works on Lithium Ion batteries, you get a base level view of the mechanisms. Lithium Polymer is essentially the same but lighter and more easily formed into different shapes.
Two key points from that article.
A lithium-ion battery pack must have an on-board computer to manage the battery. This makes them even more expensive than they already are.
There is a small chance that, if a lithium-ion battery pack fails, it will burst into flame.
Lithium batteries are composed of hundreds of smaller cells, each cell linked by the onboard computer for charging and discharging. It is the job of the microprocessor to check the heat of each of the cells and direct charge power away from overheating cells.
Later in the article it shows the separating layers in the cells. This is what failed, mainly, in the Samsung Galaxy Note7, allowing the anode and cathode to short and go on fire.
So when you are shoving massive amounts of power into these batteries, you are, essentially, pushing more small chunks of power, in parallel, to more small cells.
Of course as your battery degrades and the cells start to heat more when charging, your supercharger is going to take longer to charge them.
Also, of course, with so many cells charging in parallel, the chance that your battery will have a critical failure goes up a bit. In the end it's all down to the computer and build quality.
The fun part. All those note7's which burst into flames? 12wh. Tesla batteries? 85kwh. Sounds like quite a bonfire. Would you charge up in the garage, attached to your house? Well it is safe. Sort of. That's
never happened before has it?? Well not actually charging anyway.
But, yes, the technology is volatile, especially in an accident which may puncture the battery pack.
The article does go on to say that 17 cars, in the US, catch fire every hour. But then there are circa 300m cars in the us. If you scaled that up to all Tesla cars sold so far it would be 62. So I guess they're not doing so bad right now.