
Laminate cell bridges gap between batteries and supercapacitors
The company is struggling with what to call the UMAL low-profile high capacity energy device. Designed to meet the demand for a slim high capacity energy source with a maintenance-free extended life cycle in wireless sensor nodes, the cell has the safe charge/discharge and life-cycle characteristics of supercapcitors but the charge retention of a battery.
The UMAL cell has a nominal voltage of 2.3 VDC, can supply 12 mAh with a maximum discharge current of 120 mA and is able to withstand load fluctuations and discharges that cause problems for lithium ion batteries. This allows it to be used as a backup source for 30s to change a battery, and also as a reservoir for an energy harvesting system. It has a low internal resistance of 200 mOhm and can operate over the temperature range of – 20°C to + 70°C.
The nominal charge voltage is 2.7 VDC and the UMAL is capable of fast charging / discharge. In particular the device’s high-rate discharge characteristics mean that a peak-assist capacitor is not required. It also has a charge capacity recovery rate of over 90 % after 5,000 charge / discharge cycles and a charge retention of days,making it more like a battery than a supercapacitor.
The laminate structure with the linthium ion electrolyte gives the device a chemically stable composition that does not cause a fire or smoke hazard even if the output terminals are shorted out.
The UMAL measures 2.0 x 14.0 x 21.0 mm. for small wireless sensor nodes and also makes it suitable for wearable designs, and mass production starts this month.
www.murata.com
