Lead-acid battery with microfibre separator having improved absorption characteristics

A valve-regulated lead-acid battery is provided including separators comprising glass microfibres, plastic microfibres or a mixture of both, characterised in that the separators consist substantially of the cited glass microfibres, plastic microfibres or a mixture of both, and a filler consisting of 0.5 to 10% (w/w) silica having a specific surface higher than 700 m/g. A battery comprising such separators shows a substantial increase in the achievable working life, and a decrease in the number of possible failure modes such as short-circuits through the separator.