A filter-press-type Al/O2 battery with bipolar assembly of the electrodes was developed. The current-voltage curves and power output of monopolar and of bipolar batteries contg. one to four cells were measured in alk. (4M NaOH and 7.5M KOH) and acidic (3M H2SO4 + 0.04M HCl) electrolytes. The unit cell had an open circuit voltage of 1.85 V in alk. media and 1.3 V in acidic media. The single bipolar unit delivered a max. power of about 7.5 W (75 mW cm-2) at 0.7 V. The stack (four cells) had a max. power of 30 W in 4M NaOH and 35 W in 3M H2SO4 + 0.04M HCl. The power output of the bipolar stack detd. exptl. for different external loads could be described using the model of an elec. equiv. circuit. [on SciFinder (R)]