Lead-acid battery design having versatile form factor

An electrochemical storage device, comprising:

• a first electrochemical cell and a second electrochemical cell disposed in a common casing and each comprising an anode and a cathode, wherein the anode of the first electrochemical cell is disposed opposite the cathode of the second electrochemical cell;
• a separator disposed between the anode of the first electrochemical cell and the cathode of the second electrochemical cell, wherein the anode of the first electrochemical cell and the cathode of the second electrochemical cell are electrically insulated and in communication through an ionically conductive medium adsorbed in the separator;
• a common current collector disposed on the anode of the first electrochemical cell and the cathode of the second electrochemical cell, wherein the first and second electrochemical cells are electrically connected and insulated from ionic conduction and wherein the ionic separation of said first and second electrochemical cells mitigates shunt currents.