A battery safety vent assembly for a battery casing with an upper surrounding clamp-like shape, the battery safety vent assembly comprising: a positive cap having a disk element and a tip element upwardly protruding from the disk element, the tip element having a peripheral wall defining side openings spaced from one another and forming gas exits, the disk element having a downwardly projecting flange; a flat safety vent disk extending under the disk element of the positive cap, the safety vent disk having a peripheral rim portion fitting against the flange of the disk element of the positive cap, an arrangement of weak lines extending under the tip element of the positive cap and forming gas release openings for passage of gas when gas pressure inside the battery casing exceeds a predetermined threshold limit of pressure, and a downwardly projecting central button; a gasket insulator having a peripheral portion configured for snugly fitting into the clamp-like shape of the battery casing and defining an inwardly directed slot receiving the flange of the disk element of the positive cap and the peripheral rim portion of the safety vent disk, and an inner portion defining a central opening and a downwardly projecting U-shaped channel with upper sideways shoulders (35, 37) in contact with the safety vent disk, the shoulder and a side wall of the U-shaped channel innermost with respect to a central upright axis of the battery safety vent assembly forming an underside recess area; a circuit interrupt device having a disk-like shape fitting in the underside recess area, the circuit interrupt device having upright through holes in communication with the central opening of the gasket insulator and being coupled to the button of the safety vent disk; and a positive tab downwardly projecting from the circuit interrupt device. a positive cap having a disk element and a tip element upwardly protruding from the disk element, the tip element having a peripheral wall defining side openings spaced from one another and forming gas exits, the disk element having a downwardly projecting flange; a flat safety vent disk extending under the disk element of the positive cap, the safety vent disk having a peripheral rim portion fitting against the flange of the disk element of the positive cap, an arrangement of weak lines extending under the tip element of the positive cap and forming gas release openings for passage of gas when gas pressure inside the battery casing exceeds a predetermined threshold limit of pressure, and a downwardly projecting central button; a gasket insulator having a peripheral portion configured for snugly fitting into the clamp-like shape of the battery casing and defining an inwardly directed slot receiving the flange of the disk element of the positive cap and the peripheral rim portion of the safety vent disk, and an inner portion defining a central opening and a downwardly projecting U-shaped channel with upper sideways shoulders (35, 37) in contact with the safety vent disk, the shoulder and a side wall of the U-shaped channel innermost with respect to a central upright axis of the battery safety vent assembly forming an underside recess area; a circuit interrupt device having a disk-like shape fitting in the underside recess area, the circuit interrupt device having upright through holes in communication with the central opening of the gasket insulator and being coupled to the button of the safety vent disk; and a positive tab downwardly projecting from the circuit interrupt device.