Ultracapacitors are HIGHLY unlikely to ever be used as a main power source for any vehicle. 1: The performance is just not there, has no indication that it wil

Ultracapacitors are HIGHLY unlikely to ever be used as a main power source for any vehicle. 1: The performance is just not there, has no indication that it will improve revolutionarily, and is growing slower than batteries. Formula E uses a 250 kg, 54 kWh, 250 kW battery that does about 30 laps. Nawa is apparently[1] at 15 Wh/kg and 100 kW/kg, which would be 15x heavier for the same weight. The car would have to stop every two laps (three minutes!) to recharge- and more likely every single lap, since the actual thing will require lots of other components besides the capacitors. I'm not sure you can even call it racing when you can only complete two laps at a time. The extreme power of supercapacitors (25x more than the best li-ion) is unfortunately unusable. They need to store several times more energy to be useful. Even as assistance, they're still usually much too heavy to be worthwhile. In fact it can be argued that li-ion is already starting to surpass the power density that can be used in vehicles- VTC4 cells (an older, but notoriously powerful chemistry) can push 3.5 kW/kg when fully charged, or 1.2 megawatts for a 54 kWh battery. That's 300 horsepower from a 64 kg battery. Batteries are pushing the power higher and higher very quickly, since fast charging is so desirable. Capacitors are not improving very much at all; you can turn to nanotechnology to increase surface area or to hybrid types. "Hybrid" just means mixed with battery-like chemistry, so it's strictly worse. Nanotechnology is mostly outside near term manufacturability, but even the theoretical stuff is very limited. Increasing the surface area leads to linear gains but gets harder with n^3 since you're cramming features on top of features... and returns are already pretty bad. 2: Capacitors are very inconvenient power sources. Capacitor voltage drops with e^-t, all the way down to zero. Battery voltage drops by 40% when fully depleted, but 70% of the battery energy is in a region with <10% drop. That means it's very easy to optimize for a certain voltage, while a ton of the capacitor voltage is unrecoverable. When the voltage has dropped by 40%, as in a battery, there's still 35% of the full energy left. In practice that means those Nawa capacitors will not even reach 10 Wh/kg. Now consider accelerating a 1 tonne car to 160 kph (100 mph). The kinetic energy at 90% efficiency (neglecting friction, and drag) is 315 watt-hours, requiring a 32 kg capacitor. If you used VTC4 cells instead you could have another 5 kWh energy with 115 kW peak power output- enough for 2.8 more laps. MJ1 cells would give you 8 kWh at 40 kW peak- 4 extra laps. There's a reason f1 goes 90 minutes to two hours while formula E is only 45 minutes. Ultra- and supercapacitors (supercapacitors is more technically correct) may see use in racing or high-efficiency vehicles as boost assistance, but only if the cost comes down very significantly. They are not taken very seriously for use in EVs commercially. [1]: https://insideevs.com/news/338275/ultra-capacitor-tech-again-touted-as-ev-game-changer/ https://insideevs.com/news/338275/ultra-capacitor-tech-again...