ST’s paper-thin EnFilm rechargeable batteries - in distribution

July 17, 2014 // By Graham Prophet
Mouser Electronics has the EFL700A39 EnFilm rechargeable lithium batteries from STMicroelectronics. At 25.7 x 25.7 mm, these batteries are about the size of a postage stamp and are almost as thin, with a thickness of only 0.22 mm.

Nominal battery voltage is 3.9V with a capacity of 0.7 mAh. This battery can supply a maximum pulsed current under load of 10 mA. One of the thinnest batteries of its type, the cell has a lithium cobalt oxide (LiCoO2) cathode which gives the battery a higher capacity for its size, a lithium phosphorus oxynitride (LiPON) ceramic electrolyte which helps increase the overall energy density of the battery, and a lithium anode. The internal resistance of the EnFilm battery is 100Ω.

With a charging voltage of 4.2V it can charge to 80% of its capacity in 20 minutes. The EnFilm boasts a low capacity loss over a long cycle life. In storage, the EnFilm loses only 3% of its charge over a year which can be recovered by a recharge. Over a ten year lifecycle the battery will lose 20% of its capacity, like most lithium batteries.

The EnFilm battery is in full compliance with the IEC 62133 safety standard for non-acid batteries. It also meets both the ISO7816 and IEC10373 mechanical and flexibility standards for smartcards.

Target applications for these EnFilm batteries include Internet of Things applications, sensors and sensor networks, smart card applications, RF ID tags, energy harvesting devices, noniimplantable medical devices, backup power, and wearable applications.