a centrally - activated deferred - action silver - zinc battery has a central well defined by a stack of electrodes and separators each having a central hole . isolating washers are placed around the central holes of each metal sheet and include recesses which provide curved channels for conveying electrolyte from the well towards the electrodes . the restricted cross - section and extended length of these channels ensure a greater electrical resistance to leakage currents which flow between couples via the electrolyte during activation . pyrotechnic means are provided to activate the battery by rupturing a fragible partition and rapidly forcing electrolyte from an isolated compartment via the rupture in the partition into the well and from thence via the curved channels to spaces provided between electrodes of opposite polarity .