The prevention of lithium clusters from bridging between the negative and positive portions of a cell during discharge is described. This is done by providing a glass wool material at an intermediate location between the casing and anode current collector of a negative polarity and the cathode current collector and the terminal pin being of a positive polarity. Typically, a lithium ion concentration gradient sufficient to cause lithium cluster formation is induced by the high rate, intermittent discharge of a lithium/silver vanadium oxide (Li/SVO) cell. However, sufficient free electrolyte necessary for normal cell function is held in the relatively large pore volume throughout the extent of the glass wool material. Moreover, permeability within the glass wool material is tortuous, which effectively increases the distance between the negative and positive surfaces of the anode and cathode. This tortuosity effectively stops “straight line” dendrite growth of lithium clusters between opposite polarity structures inside the casing.