Lead-acid accumulator

The utility model relates to a leakless and maintenance-free lead-acid accumulator, which is composed of a polar plate sealed in an accumulator casing, the electrolyte and electrodes connected with the polar plate. The top cover of the casing is provided with a ventilation catalyst chamber storing the catalyst formed by the mixing and drying of silicon oxide, platinum metal and water repellent. The catalyst chamber is provided with a safety valve, and because the water vapor can enter the catalyst chamber and circulate passing the action of the catalyst without overflowing and loss, the utility model can not pollute the environment but can reduce the use cost.