High-voltage liquid-electrolyte microbatteries composed of serial unit cells defined by the surface-tension effect

Abstract

We present high-voltage liquid-electrolyte microbatteries, inspired by the high-voltage generation mechanism of electric eels using serially connected unit cells. Compared to the previous stacked micropower sources, the present microbatteries achieve easy liquid-electrolyte filling with reduced charging time. In order to isolate each cell, we purge air into the liquid electrolyte filled in a channel layer, with three types of surface-tension valves (cell-front, outlet and cell-end valves). We design and characterize four different prototypes of microbatteries: C1, C10, C20 and C40, composed of the serial interconnection of 1, 10, 20 and 40 unit cells, respectively. In the experimental study, we measure threshold pressures of the three surface tension valves of cell-front, outlet and cell-end valves as 460 ± 47, 1000 ± 53 and 2800 ± 170 Pa, respectively. The average charging time of C40 has been measured as 26.8 ± 4.9 s where the electrolyte and air flow rates are 100 and 200 μl min −1 , respectively. The prototypes of the microbattery C40 show a maximum voltage of 12 V, a maximum power density of 110 μW cm −2 and a maximum power capacity of 2.1 μAh cm −2 . The present microbatteries have the potential for application in high-voltage portable power sources.

Acrylated hyperbranched polymer photoresist for ultra-thick and low-stress high aspect ratio micropatterns

“…A micro-battery channel structure having a series of unit cells [2] was produced using the proposed fabrication process with the acrylated polyether HBP. The chip size was 2.22 cm × 1.45 cm and consisted of two inlet ports, one outlet chamber and 10, 20 and 40 unit cells including the channel and valve.…”

“…For some of these devices [2,3], comparatively thick polymer layers in the order of a few hundred micrometers are required, such as those based on polydimethysiloxane (PDMS) and fabricated by a simple but time-consuming molding process using photoresist patterns as a master. Processes used for microstructuring polymer materials for microsystem applications include replication methods and direct techniques [4].…”