No, those peaks still internally per cell at ~5V, and the flammability is still about lower than that of a petrol car.
The difference is not in voltage, but in current. Current charging stations (labeled 300kw) have a range of 200-900V, and current “800V” cars like my Ioniq 5 have the capability between 200-800V. Teslas, for example, can handle up to 500V.
Volt = voltage, Ampere = force, and a multiplication of voltage by force = power.
To charge a car with 200kW or more, you need 500A to do it with 400V. And that is precisely what causes heat. If you do it with 800V, you suddenly only need 250A. Suddenly you can use thinner cables!
The joke is that a car naturally has all kinds of branches internally, to each individual cell. My Ioniq 5 has 384 cells divided over 32 modules. Each module is more or less individually cabled, and is therefore simultaneously charged with a lower power by the DC charger that uses this voltage, while the car and the pole monitor the temperature of each cell during this charging, and cool AND heats (according to need). Obviously this works differently if you are charging via AC, after all, there is no 800V coming from your socket. After all, in the Netherlands 230/400V comes from the socket (after all, 3-phase three-phase current is the norm here, 3 phases separated at 120 degrees with one neutral).
When the cells arrive individually, the capacity is so low that the fire risk is nil, in fact: we usually have to heat.
The whole story is significantly different from LPG tanks where a pressure drop can occur. Moreover, fast charging is not something that usually happens in a parking garage, so the whole 800V story is not a factor there. Unloading is a whole different story.
I think that with an 800V architecture, the fire risk can potentially even decrease, because the biggest bottleneck, the cable thickness, is potentially less extreme: the cables need to be less thick.
The voltage is of course also a factor for driving, but because most EVs drive with a variable frequency induction motor, an inverter is needed anyway, and therefore in principle a different system than the charging system. Furthermore, EVs tend to solve the “more power” problem with “more motors”, so a Model S Plaid has three, for example. But the association 800V is usually intended for charging here, and then specifically fast charging. Something you usually don’t do with an EV unless you make an absurdly long drive (a fast charger is a ‘range extender’). And those things are on the spot where gas stations are now. Not in parking garages. Those are AC poles.
[Reactie gewijzigd door Umbrah op 6 februari 2023 15:18]
