One variation of a battery unit includes: a series of anode collectors; a set of anode electrodes including anode material arranged on both side of the anode collectors; a set of anode interconnects interposed between and electrically coupling adjacent anode collectors and folded to locate the anode collectors in a boustrophedonic anode stack; a series of cathode collectors; a set of cathode electrodes including cathode material arranged on both side of the cathode collectors; a set of cathode interconnects interposed between and electrically coupling adjacent cathode collectors and folded to locate the cathode collectors in a boustrophedonic cathode stack with cathode collectors interdigitated between anode collectors in the boustrophedonic anode stack; and a set of separators arranged between the anode and cathode electrodes and transporting solvated ions between the anode and cathode electrodes.