An electrical component can take in power, release it quickly, and do it again and again. A U.S. intelligence agency document examined one such component, known as an ultracapacitor: a device that stores electricity and delivers it in short bursts.
It can withstand hundreds of thousands of charge-and-discharge cycles. But for its weight, it stores less than one-tenth as much energy as a lithium-ion battery. Its advantage isn’t how long it can run, but how quickly it takes in and delivers electricity.
Power When You Need It Now
A battery is suited to supplying electricity over time. An ultracapacitor is better for systems that need a brief, powerful boost or must transfer electricity quickly. It can deliver power repeatedly without a long wait to recharge between bursts.
One simple example in the document is backup power for memory and clocks in devices. If the power supply is interrupted, an ultracapacitor can provide power briefly. The document also mentions systems in which it helps handle a sudden increase in electricity demand.
Why Did an Intelligence Agency Study It?
The document was produced as part of a program examining technologies that could be of interest to aviation and military systems. Ultracapacitors seemed especially well suited to systems that need short bursts of power, rather than a source of electricity that lasts over time.
The review describes possible uses in transportation, aviation, and military systems. It also mentions short-term power for missile and munitions systems. The document notes civilian applications, too, such as backup power and stabilizing the electricity supply. The basic idea is simple: when a system suddenly needs more power, an ultracapacitor can deliver a boost quickly.
What We Still Don’t Know
The document is a review of the technology, not original research. It doesn’t prove that all the military and space applications it describes were ever realized, and ultracapacitors aren’t a suitable replacement for batteries in every situation.
A battery stores more energy. An ultracapacitor excels when power is needed, and needed fast. Sometimes that’s the difference between waiting for electricity and getting it right away.
