Sealed lead acid battery

Claim 1

A sealed lead acid battery comprising: (a) a container having a rectangular base, four side walls approximately perpendicular to said base and a plurality of vertical partitions dividing said container into a series of separate chambers, said container being formed from a polypropylene resin containing 5 to 20% inert filler and having a wall thickness of 2 to 4 millimeters; (b) a plurality of cell elements inserted into said chambers, each cell element consisting of at least one rectangular negative plate and at least one rectangular positive plate, arranged serially, each plate being separated from the next by a rectangular, microfibrous, glass separator, having a length and a width greater than that of said plates, said cell elements being pressed into said chamber so as to have an enforceable positive pressure on said negative and positive plates of between 35 and 60 kg/cm 2 ; (c) a plurality of straps, connecting the positive and negative plates of each cell respectively; (d) a cover body sealed to said container, said cover body having a plurality of filler ports, a negative terminal, a positive terminal, and a gas collection system consisting of a common manifold, venting passages connecting said manifold to openings in the top of each of said chambers, a common vent, said vent being formed in a recess in the surface of said cover and comprising a cylindrical, small diameter tube projecting vertically from said common manifold, a plurality of notches formed in the upper portion of said tube, and an elastic cap vertically and horizontally covering said upper tube portion; (e) a gas permeable filter, fixedly arranged in said vent, superimposed upon and restraining said elastic cap of said common vent; and (f) a loosely fitting cover detachably mounted upon said cover body over said filter, wherein said elastic cap positively seals the upper tube portion, and said elastic cap is arranged with said upper tube portion to release gas through said filter by opening of said elastic cap, by itself, when the gas pressure within the common manifold is between 0.2 to 0.4 kg/cm 2 above ambient atmospheric pressure.