A battery including: a casing (101A, 101B, 101C) having an inner surface defining a chamber in which an electrolyte is disposed therein; a conductive surface located within the chamber adjacent the inner surface of the casing (101A, 101B,101C), the conductive surface being configured for electrical communication with an anode terminal of the battery; a permeable separator sheet located within the casing (101A, 101B,101C) configured for electrically isolating the electrolyte from the conductive surface; a conductive rod having a first end configured for electrical communication with a cathode terminal of the battery, and, a second end of the conductive rod configured for electrical communication with the electrolyte; and an opening disposed in the casing (101A, 101B,101C); the casing (101A, 101B,101C) including at least a first and second portion that are movably attached to each other, the first and second portions (101A, 101B) being movable relative to each other between at least a first attached position whereby the opening is substantially blocked from allowing ingress of a liquid into the casing (101A, 101B,101C) via the opening, and, a second attached position whereby the opening is substantially unblocked so as to allow ingress of the liquid into contact with the electrolyte in the chamber via the opening to activate the battery by generating a potential difference between the conductive surface and the conductive rod; wherein the opening disposed in the casing (101A, 101B,101C) is configured to allow ingress of the liquid therethrough into the chamber when the casing (101A, 101B, 101C) is submerged in the liquid. a casing (101A, 101B, 101C) having an inner surface defining a chamber in which an electrolyte is disposed therein; a conductive surface located within the chamber adjacent the inner surface of the casing (101A, 101B,101C), the conductive surface being configured for electrical communication with an anode terminal of the battery; a permeable separator sheet located within the casing (101A, 101B,101C) configured for electrically isolating the electrolyte from the conductive surface; a conductive rod having a first end configured for electrical communication with a cathode terminal of the battery, and, a second end of the conductive rod configured for electrical communication with the electrolyte; and an opening disposed in the casing (101A, 101B,101C); the casing (101A, 101B,101C) including at least a first and second portion that are movably attached to each other, the first and second portions (101A, 101B) being movable relative to each other between at least a first attached position whereby the opening is substantially blocked from allowing ingress of a liquid into the casing (101A, 101B,101C) via the opening, and, a second attached position whereby the opening is substantially unblocked so as to allow ingress of the liquid into contact with the electrolyte in the chamber via the opening to activate the battery by generating a potential difference between the conductive surface and the conductive rod; wherein the opening disposed in the casing (101A, 101B,101C) is configured to allow ingress of the liquid therethrough into the chamber when the casing (101A, 101B, 101C) is submerged in the liquid.