Ultracapacitors

Ultracapacitors (or ultracaps) provide an environmentally friendly power source as an alternative to batteries. Ultracaps are best suited for applications that require high power in short bursts. This makes them an excellent fit for non-volatile memory systems, such as AGIGARAM®, that require only 10-20 seconds to back-up contents of DRAM to Flash.

Innovations in capacitor technology have enabled a significant increase in capacitance with minimal impact to size.

The dramatic increase in capacitance/volume is made possible by an entirely new way to build a capacitor. But first, a little Physics 101.

The capacitance of a parallel-plate capacitor increases as:

  • The plate area A increases, and
  • The plate separation d decreases

The dramatic increase in ultracap capacitance/volume is made possible by an entirely new way to build a capacitor.

 

An ultracap is made from two porous electrodes soaked in an electrolyte solution with an insulator (separator/ionic conductor) between them. When voltage is applied, ions from the electrolyte accumulate along the porous surfaces of the two electrodes. The capacitance is greatly increased compared with that of ordinary capacitors, due to two factors:

  • The charge separation distance d is governed by the size of the ions, which is on a molecular scale.
  • The enormous surface of the pores give the electrodes a huge surface area on which to collect charge.

One teaspoon of activated charcoal contains the surface area of a football field.

The diagram to the right greatly exaggerates the thickness of the porous surface on each electrode. The carbon is actually a thin coating on the electrode. The two coated electrodes give rise to the term "double-layer".

Huge A + Tiny d, equals huge capacitance/volume.

While batteries chemically separate positive and negative charges, ultracaps physically separate charges with no reaction or chemical "wear". The non-chemical reaction explains the cycle life of ultracaps—in the 100,000's—as well as the quick charge and discharge rates.

AGIGACAP™ Ultracapacitor

AGIGACAPS™

AgigA Tech has established a reliability test lab in Chengdu, China and has been continuously testing ultracaps for over 3 years amassing a significant amount of test data that is unmatched in the industry. The test lab continues to run 24 hours a day, 7 days a week. AgigA Tech has tested the ultracap offerings of multiple manufacturers, and at extended operating temperatures and voltages. Based on this extensive test data, AgigA Tech has selected the most reliable ultracap products to incorporate into the PowerGEM modules.

Chengdu test lab chart

It is important to note that ultracaps from various vendors age in different ways. Based on this extensive test data, AgigA Tech has selected the most reliable ultracaps to incorporate into our PowerGEM® products.

Ultracap curves chart