Development of micro batteries based on micro fluidic MEMS packaging

A cost effective and reliable technology allowing extreme miniaturization of batteries into silicon, glass chips and electronic packages has been developed, employing a dispense-print process for battery electrodes and liquid electrolyte. Lithium-ion micro batteries (active area 6×8 mm2, 0.2-0.4 mAh) with interdigitated electrodes and glass housing were fabricated, tested and finally compared with the traditional battery architecture of stacked electrodes. All processes for micro battery fabrication were established; in particular a micro fluidic electrolyte filling process that allows simultaneous electrolyte supply of all cells on a planar substrate. Electrode mass reproducibility was sufficient for adequate electrode balancing. Current capability similar to the conventional face-to-face electrode configuration was achieved with interdigital electrodes. The cells were successfully cycled; several 100 cycles can be achieved.