Electrochemical reaction under the available type lead-acid batteries, said: PbO2 + 2 - h2so4 + Pb + 2 h2o + PbSO4 PbSO4
(lead dioxide) (sulfuric acid) (sponge) lead (lead sulfate) (water) level (lead sulfate electrolyte electrolyte is living material cathode material The positive product discharge cathode discharge Ordinary lead-acid battery, in the late charge, water decomposition reaction will happen, that is, from the positive to produce oxygen, the cathode hydrogen, and spread into the air, so often need to fill with water compensation for the loss of the electrolyte. And then in our VRLA battery, charging the positive of oxygen in the cathode is complex, known as the "oxygen cycle" or "oxygen compound. In the positive: in the cathode: 1/2 O2 + 2 H2O 2 H + + e - o2 + Pb + 1/2 - H2SO4 PbSO4 + H2O PbSO4 + 2 H + + e - Pb 2 + H 2 so4 in this cycle, the net result is the positive water decomposition, in the cathode and regenerated water, specific expression is as follows: in the process of battery electrolyte liquid "greed", namely the superfine fiber glass partition in about 5% of the microporous as gas channels are not in the possession of the electrolyte. When charging, the anode water decomposition of oxygen will spread along the airway to the anode, and the shape of the cathode sponge lead, generating water returned to the electrolyte. At the same time, the generated lead sulfate in charge again into the lead. Oxygen compound in the cathode is at the same time, and drawn up the production of hydrogen at the cathode, which is cause and maintenance-free sealed VRLA battery can be realized.