Battery charge control for emergency back-up systems

For many years, intensive research has been undertaken to increase the life of batteries. Overcharging results in excessive temperature in the battery, which degrades the chemical composition of the electrolyte. During charging, when the battery reaches end-of-charge, the energy being supplied to the battery is no longer consumed in the charge reaction and this additional energy starts dissipating as heat within the battery. At this point, the oxygen cycle accelerates, which leads to temperature rise inside the battery. State-of-the-art control technology is required to control the charging of the battery and prevent the battery going into thermal runaway. The paper contrasts and compares Valve Regulated Lead Acid (VRLA) and NiCd batteries. A sophisticated microprocessor-based battery charge control system is described.