I thought I had blogged about ultracaps before, but a search didn’t show anything … so here we are.
Ultracapacitors (or ultracaps) are an energy storage device that operate differently to batteries. The main point of difference seems to be in their charge / discharge times – radically faster than batteries. They also handle many more cycles with degrading (the so called memory effect of batteries, for example.) However, all shipping ultracaps have lower energy density than batteries – which means you get to store less electricity per kilogram of device. In fact as low as one tenth of the density at present. Fancy carrying an ultracap that weighs ten times as much as your batteries? Me either.
Along comes a story about a startup called EEStor and how they are claiming to have broken the density problem. That would of course be fantastic, but I’d be wary that this is another press release to hype investors … seeing one of the biggest VC funds in there doesn’t, strangely, reassure me at all.
Ultracaps do have applications in electric vehicles, quite successfully in regenerative braking systems where the high charging rates are suitable – as is the high power available to get your vehicle off the mark again. Whether EEStor (or others) can break through the density problem and replace chemical batteries remains to be seen at this stage, I for one would love to see it happen.