I've wondered about hybrid supercap/battery designs as well, but up until recently it's apparently often been easier/better to just go with a bigger battery. St

I've wondered about hybrid supercap/battery designs as well, but up until recently it's apparently often been easier/better to just go with a bigger battery. String more small cells up together, get more performance and also more absolute energy available (range). That said, while it's a completely and utterly different area, I've actually now experienced my first hybrid using equipment just a few weeks ago and it was pretty interesting: the latest Black Diamond avalanche airbag (JetForce Tour 26L). Avalanche airbags are now quite common safety tools for heavy snow back country or mountaineering, and in an avalanche can help keep a person from being completely buried (or at least keep them much much shallower). Fundamentally, they need to extremely rapidly inflate a significant volume with gas or air on demand, with long term reliability in standby, and while being part of a human portable backpack carrying other stuff and thus as light as feasible. It doesn't take much absolute energy, but inflating in a couple of seconds does take a huge amount of power. The original ones used compressed air or small explosives, which obviously are consumable and present problems traveling by commercial air. They're also harder to test/practice with. Electric fan models came about like 5-6 years ago, but extremely high instantaneous power demands in this application meant big fat lithium ion batteries which are fairly heavy. Fine in a car, not so man portable. The JetForce uses Alpride's E1 supercap design fan. The supercap can be charged off of USB or just a single pair of AA batteries in the field, and can hold charge for a good 2-3 months. It shaves a solid couple of pounds off the previous lithium ion design. Anyway, niche application but it was pretty neat to me anyway to see some real practical gains come about from newer supercap work. I'll be curious if hybrid designs continue to make inroads in other places characterized by sharp power spikes with less overall energy demand.