NOVELTY - A sealed maintenance-free lead-acid storage battery contains battery shell made of acrylonitrile butadiene styrene engineering plastics, and partition board using fiberglass membrane. The positive grid alloy comprises 100 kg pure lead ( greater than or equal to 99.994% pure), 0.04-0.08 kg calcium, 0.01-0.08 kg sodium, 0.01-0.1 kg aluminum, 0.01-0.1 kg copper, 0.01-1.5 kg tin, and 0.01-0.03 kg bismuth. The negative grid alloy comprises 100 kg pure lead, 0.05-0.2 kg calcium, 0.2-1.2 kg tin, 0.01-0.2 kg aluminum, 0.02-0.2 kg copper, and 0.01-0.1 kg bismuth.    USE - Sealed maintenance-free lead-acid storage battery for miner's safety cap lamp.    ADVANTAGE - The battery has useful time of greater than or equal to 500 times.    DETAILED DESCRIPTION - Sealed maintenance-free lead-acid storage battery comprises battery shell made of acrylonitrile butadiene styrene (ABS) engineering plastics, and partition board using fiberglass membrane. The positive grid alloy comprises 100 kg pure lead ( greater than or equal to 99.994% pure), 0.04-0.08 kg calcium, 0.01-0.08 kg sodium, 0.01-0.1 kg aluminum, 0.01-0.1 kg copper, 0.01-1.5 kg tin, and 0.01-0.03 kg bismuth. The materials of the alloy are heated at 480-550 degrees C in a lead smelting furnace, and after the alloy is smelted, the temperature is preserved for 20-30 minutes. The positive grid is formed after the smelted alloy is stirred, and a plate coating process is performed after the formed grid has been left in dry condition for 24 hours. The positive active material of the battery comprises 100 kg lead powder having oxidation degree of 76-80% added with 12 l sulfuric acid solution at a ratio of 1.08-1.2 g/cm3, 0.01-0.2 kg Picconol A500(RTM: hydrocarbon resin), 0.05-0.5 kg of 300-400 mesh heteromorphic graphite, 0.01-0.5 kg cobalt sulfate, and 0.01-0.5 kg bismuth oxide. The materials of the battery are prepared into diachylon at a ratio of 4.2-4.26 g/cm3 by pure water, coated to the positive grid after being stirred in a paste mixer, and made into positive polar plate by solidification and formation. The positive polar plate for assembling the battery is made by 2 positive polar plates with a gap of 0.2-0.6 mm between them. The gap is filled with flocculent fiberglass, colloid electrolyte, or 0.1-0.15 mm hole-contained plastic sheet. The negative grid alloy comprises 100 kg pure lead, 0.05-0.2 kg calcium, 0.2-1.2 kg tin, 0.01-0.2 kg aluminum, 0.02-0.2 kg copper, and 0.01-0.1 kg bismuth. The materials of the negative grid alloy are heated to 480-540 degrees C in a lead smelting furnace, and after the alloy is smelted, the temperature is preserved for 20-30 minutes. The negative grid is formed after the smelted alloy is stirred. The negative active material of the battery comprises 100 kg lead powder having oxidation degree of 75-80% added with 0.2-0.8 kg cobalt sulfate, 0.1-0.8 kg Lignosol TSD(RTM: ammonium lignin sulfonate), 0.1-0.3 kg alpha , beta naphthoic acid, 0.05-0.4 kg graphite having granular size of 600-800 mesh, 0.1-0.3 kg acrylic short fiber, 0.3-0.8 kg humus acid, and 0.3-0.8 kg barium sulfate. The negative active material is coated to the negative grid after being stirred in a paste mixer and made into negative polar plate by solidification and formation. The positive and negative polar plates are assembled into polar group. The design of the battery uses cathode excess that the negative polar plate is more than the positive polar plate by one piece. The positive polar plate is enveloped by the fiberglass membrane and enclosed into the battery shell by compression according to certain compression ratio. An upper cover of the battery is agglutinated to the shell by an adhesive, and electrolyte. The electrolyte comprises sulfuric acid solution containing 1.29-1.295 g/cm3 acid, 0.01-1.5% dimethyl sodium phosphate, and 0.001-0.2% sodium sulfate.