Traditionally, automotive batteries have been bulky and heavy. But, some day in the future, batteries may be printed rather than assembled.

A new battery developed by engineers at the Fraunhofer Research Institution for Electronic Nano Systems is less than 1 millimeter thick. It weighs less than 1 gram and can be economically mass-produced by using conventional printing processes.

“The characteristics of the printable battery differ significantly from traditional batteries,” says Reinhard Baumann, a professor who led the team of Fraunhofer engineers. For instance, the printable version contains no mercury, making it environmentally friendly. Its voltage is 1.5 volts, which lies within the normal range. By placing several batteries in a row, higher voltages, such as 3 or 6 volts, can be achieved.

The new battery is composed of several different layers, including a zinc anode and a manganese cathode. “Zinc and manganese react with one another and produce electricity,” explains Baumann. “However, the anode and the cathode layer dissipate gradually during this chemical process. Therefore, the battery is suitable for applications that have a limited life span or a limited power requirement, such as greeting cards.”

The batteries are created with a silk-screen printing method similar to that used for t-shirts and signs. A 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,” says Baumann. “The individual layers are slightly thicker than a hair.”