Printable batteries

For a long time, batteries were bulky and heavy. Now, a new device is thinner than a millimetre, lighter than a gram, and can be produced cost-effectively through a printing process.

The printable battery was developed by a research team led by Prof Dr Reinhard Baumann of the Fraunhofer Research Institution for Electronic Nano Systems ENAS in Chemnitz, together with colleagues from TU Chemnitz and Menippos GmbH.

“Our goal is to be able to mass-produce the batteries at a price of single-digit-cent range each,” said Dr Andreas Willert, group manager at ENAS.

The characteristics of the battery differ significantly from those of conventional batteries. The printable version weighs less than 1 g, is not even 1 mm thick and can be integrated into bank cards, for example.

The battery contains no mercury and is therefore environmentally friendly. Its voltage is 1.5, which lies within the normal range. By placing several batteries in a row, voltages of 3, 4.5 and 6 can also be achieved.

The battery is composed of different layers: a zinc anode and a manganese cathode, among others. Zinc and manganese react with one another to produce electricity.

However, the anode and the cathode layer dissipate gradually during this chemical process. Therefore, the battery is suitable for applications which have a limited life span or a limited power requirement, eg, greeting cards.

The batteries are printed using a silk-screen printing method similar to that used for T-shirts and signs. A kind of rubber lip presses the printing paste through a screen onto the substrate. A template covers the areas that are not to be printed on.

Through this process it is possible to apply comparatively large quantities of printing paste and the individual layers are slightly thicker than a hair. The researchers have already produced the batteries on a laboratory scale.

At the end of this year, the first batteries may be commercially available.