What is Valve Regulated Sealed Lead-acid Battery (AGM)?

Valve controlled sealed Lead Acid Battery, whose English full name is Valve Regulated Lead Acid Battery, that is a rubber Valve sealed Lead Acid Battery, the use of the cathode adsorption principle to achieve oxygen cycle, so that the positive gas recombination. 

Its basic characteristic is to use it without acid water during maintenance, battery for sealing structure, does not leak acid, also won't row acid mist, battery lid has a one-way valve (also called safety valve), the valve when the battery is the function of internal gas volume exceeds a certain value, i.e. when the battery internal pressure increases to a certain value, the exhaust valve opens automatically, discharge gas, when reduced to closing valve pressure value, the safety valve closes automatically. 

Valve controlled battery was born in the 1970s, to the 1980s, in some developed countries has formed a considerable scale of production, soon formed industrialization and a large number of market.