Amberwolf, while everything can burn, these cells seem to take quite some work to burn. Citing their website:
Destructive tests have demonstrated the safety of the cells: short circuit, overcharging, forced discharging, fire, drop test, nail puncture (internal short circuit), even shooting on it with a gun showed no fire and no explosion.
Fetcher, they don't seem to be the same as the Maxcell, at least the Durablue:
From:
https://newatlas.com/energy/toomen-powercapacitors-kurt-energy-high-density-supercapacitors/
Citing:
There are currently two variants, one that prioritizes energy density and the other delivering maximum power rates. The high density cells are currently offering between 200-260 Wh/kg, with rated power densities around 300-500 W/kg. The high power cells are getting 80-100 Wh/kg, with power densities around 1,500 W/kg, peaking at up to 5,000 W/kg.
...
To put those numbers in context, a current model commercial ultracapacitor like the DuraBlue from Maxwell offers a much, much lower energy density of just 8-10 Wh/kg but a sky-high power density around 12,000-14,000 W/kg. A good lithium battery, on the other hand, typically offers 150-250 Wh/kg and power-wise is somewhere around the 250-350 W/kg area. So while it's clearly a trade-off between power and energy storage, the Toomen power capacitors certainly offer power advantages at the high density end of the scale, and huge density advantages at the high-power end of the scale.