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72/Miscellaneous/Ask George/Oxygen Recombination 080815
(July, 02) Question:Is it true that a lot of investigative work is being done to control / influence the oxygen recombination in a VRLA battery?

Answer: Many companies are attempting to influence the oxygen recombination in these type of batteries. A lot of patents are being seen which attempt to control the flow/ diffusion of the oxygen from the positive to the negative by the use of hybrid type formulation. Here an ingredient is added to the all glass separator that imparts some areas of the sheets that has higher hydrophobic sites than other parts of the separator, thus providing for easier diffusion of the oxygen. One of the earliest inventors that realized the importance of this, plus the importance that the added toughness a hybrid separator provides, was John Badger. His patent number 4,908,282 highlighted the many important properties that the separator can provide to the battery’s performance. A copy of the abstract to this important patent is reprinted here.

United States Patent, Badger No. 4,908,282 issued - March 13, 1990
Recombinant battery and plate separator therefore

A fibrous sheet useful as a battery plate separator is disclosed. The sheet, in a specific embodiment, is made from a mixture of Grade 210 glass fibers, Grade 206 glass fibers, Grade A-20 chopped glass strand, and Grade A-121 polyethylene fibers. The fine glass fibers impart a high absorbency to the sheet; the coarse glass fibers impart a lower absorbency; and the polyethylene fibers, which are hydrophobic, are essentially non-absorbent. The different fibers are used in such proportions that the sheet has the absorbency, usually from 75 to 95 percent, required for use in a recombinant battery, even in the presence of free electrolyte. A recombinant battery in which fibrous sheets as described above serve as plate separators is also disclosed, as is a method for producing a recombinant battery which includes the steps of assembling a plurality of electrodes with such sheet separators in a case, flooding the electrodes in the case with an electrolyte, removing electrolyte that is not absorbed by the sheet separators from the case, and closing the case. Finally, a recombinant battery in a case which has an opening is also disclosed; the opening is closed by a thin film of polyethylene or the like through which hydrogen can escape at a faster rate than oxygen.