Overview, Background of Development

Lead-type electric double-layer capacitors are used in backup power sources for game consoles, as well as in auxiliary power sources for printers and projectors. They are also becoming the capacitor of choice for use in backup power sources for the smart meters which have gained popularity in recent years around the world. Because smart meters must have instantaneous power output when conducting wireless transmission, they require low-resistance power devices. And because they are installed outdoors, their power devices must be able to function within a wide temperature range; particularly pressing has been the need to improve these devices' resistance characteristics to withstand operation in low temperatures. 
Nichicon's UK Series was developed to meet the needs of smart meter manufacturers who require capacitors with lower resistance and the ability to operate in a lower temperature range.

Main Features

The UK Series achieves lower resistance through the adoption of newly developed electrodes and electrolyte solution. Nichicon reduced resistance over conventional electrodes by approximately 50% by optimizing parameters such as the pore size of the activated charcoal and the thickness of the electrodes. For the electrolyte solution, instead of using acetonitrile which is used by many companies around the world as a solvent since it offers reduced resistance because of its low viscosity, but which also gives off possible toxic gasses if burned-Nichicon adopted a propylene carbonate-based solution that offers greater safety and a lower environmental impact. With a solute and solvent composition that achieve the lowest possible resistance, Nichicon's newly developed electrolyte offers approximately double the conductivity of conventional solutions. The result is the lowest resistance in the industry for non-acetonitrile electrolyte capacitors: the UK Series offers resistance as low as one-third that of equivalent sized products in Nichicon's UM Series. 
Nichicon has also dramatically improved the low-temperature characteristics of the capacitor: while the company's current products offer low temperature stability down to -25°C, the UK Series is guaranteed to -40°C.

In addition to smart meters, electric double-layer capacitors are also becoming the choice for backup power sources in products like drive recorders and storage servers, and as a replacements for secondary batteries since they require no maintenance and have minimal environmental impact. 
With the goal of increasing the number of applications, Nichicon is working to develop capacitors that can operate at higher temperature ranges and withstand higher voltages.

Relation between temperature and internal resistance
Comparison of UM Series and UK Series in case size of 12.5 × 31.5 L (mm).

Main Specifications

Rated Voltage	:	2.5V DC
Rated Capacitance Range	:	6.8 to 27F
Category Temperature range	:	-40 to +70°C
Product Dimensions	:	12.5 × 31.5 L (mm) to 18 × 40 L (mm)
Endurance	:	1,000 hours at 70°C
Terminal Shape	:	Radial Lead Type