Powercaps provide the best of two energy worlds

The Karlsruhe Institute of Technology (KIT) has developed Powercaps — energy storage systems that combine the advantages of batteries and supercapacitors. The systems are a result of a project to develop the next generation of energy storage systems for industry, FastStorageBW II.

A battery can absorb a lot of energy and save it for a long time, but it takes a long time to charge, has a limited lifespan and withstands only a limited number of charge cycles. A capacitor, on the other hand, absorbs energy quickly and is durable, but does not have the storage capacity and endurance of a battery.

“The goal is to create a hybrid that combines the advantages of batteries and capacitors,” said KIT’s Dr Olaf Wollersheim, with the market potential of such a hybrid said to be enormous.

“It already amounts to roughly half a billion euros, and in four to six years it could reach two or three billion euros,” said Edward Pytlik, who manages the R&D department at VARTA Microbattery.

VARTA managed to derive the new Powercaps from lithium-ion batteries, albeit with an aqueous electrolyte system. This averts the danger of combustion, which until now was an important argument for barring conventional lithium-ion batteries from many industrial sectors. In addition, the electrochemical storage units are able to effectively buffer peak loads in factories.

“Quite often cables, transformers and electronics are set for a peak load of, for example, 300 kW, although on average only 3 kW are needed,” said Dr Wollersheim. “With the new Powercaps, the peak value can be limited to 10 kW, which enables tremendous cost savings.”

Powercaps can be applied in all areas where power demand fluctuates. Potential uses include peak-load buffering in companies with high power demand, uninterruptible power supply and frequency control in power grids. Two intralogistics companies that already contribute to FastStorageBW II will be the first to use the newly developed prototypes.

Image credit: Mohamed Elkadragy, Karlsruhe Institute of Technology.