The unveiled cylinder-shaped cell
The unveiled cylinder-shaped cell
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Hitachi AIC Inc. unveiled a lithium ion capacitor that the company is currently developing for the first time at CEATEC JAPAN 2007.

Exhibited is a disk-shaped cell named "18650", which is 18 mm in diameter and 65 mm in thickness. The energy density per volume is 15 Wh/L, according to the company.

The rated capacity is 100-150 F, while the maximum voltage is 4 V. The weight is reportedly 25-33 g. The internal resistance is 10-60 mΩ. The company says it is also developing a cylinder-shaped cell "40100", which is 40 mm in diameter and 100 mm in length.

Its rated capacity is 800-1200 F, while the energy density and maximum voltage are equivalent to those of 18650. Its internal resistance is 2-10 mΩ, according to the company. 40100 is intended for application on an auxiliary power used for shutting off/starting of a vehicle engine at the time of idling.

The company says it has been developing a lithium ion capacitor, which is doped with lithium ion on the negative terminal since several years ago. Increasing number of capacitor manufacturers are developing lithium ion capacitors because they are capable of boosting the energy density of cells.

Manufacturers including Taiyo Yuden Co., Ltd, FDK Corporation and Advanced Capacitor Technologies, Inc. also exhibited the products they have developed at CEATEC.