Flexible, printed thin film batteries with increased discharge current
Fraunhofer ENAS has been working on the production of printed primary batteries and application developments in close cooperation with the Chemnitz University of Technology for 10 years. Primary batteries have the advantage that they are fully charged after the manufacturing process and can be used immediately. Form (so far 1 cm² to 300 cm² in size realized) and voltage (1.5 to 30 V) can be varied within wide limits. The capacity for a single cell is up to 5 mAh/cm² and scales linearly with the pattern area. Due to its internal resistance, the established battery solution makes sense for applications that require a maximum of 1 mA of current. Higher currents lead to a significantly lower operating voltage for the consumer. To increase the current flow significantly, the battery cells are manufactured with an additional layer of silver conductor. This allows a reliable voltage supply at 10 mA current flow. This is particularly necessary in the field of sensor systems, since the current demand exceeds 1 mA for a short time and was not feasible with the battery systems available so far.