Modified water-activated battery

A water-activated, deferred-action battery having a battery housing (17A) ) and/or a battery attachment housing (20) containing at least one cell, comprising: at least one anode (17B); at least one cathode (17C), at least one cavity (17E) separating said at least one cathode (17C) and said at least one anode (17B); and at least one aperture (17F) leading to said at least one cavity (17E) for the ingress of an electrolyte- forming, aqueous liquid, characterized by an electrolyte containing housing member (22, 23) having an inlet opening (23A) in a distant end of said housing member (22, 23), a through passage formed in an electrolyte containing space (22A) for an electrolyte composition (27) and an outlet opening (22B) in a proximate end of said electrolyte containing housing member (22, 23), said electrolyte containing housing member (22, 23) being positioned in a flow path leading to said aperture (17F), wherein an inner filter (21A) is arranged across said flow path next to said electrolyte containing space (22A) adjacent said outlet opening (22B).