Development of a small size VRLA long life battery for telecommunication

This paper discusses some of the key design parameters needed to improve trickle life in small size VRLA batteries. The VRLA battery is becoming increasingly common in many places for telecommunication back-up, and it operates under very severe environmental conditions. Trickle life batteries have been developed for about fifteen years, and their models are 12V15AH, 12V24AH, 12V38AH and 12V65AH batteries. Some of the key design parameters have been investigated to improve trickle life: positive grid growth; charging current; and thermal runaway. From the analysis of accelerated life test results, battery trickle life was subject to three major factors: positive grid growth; water loss from the cell container; and charging current. Also, it is thought that the charging current effects the positive grid growth and corrosion. This is the most important design parameter to improve battery-life. From the FRA impedance analysis of the negative electrode, it was shown that the trickle charging current was affected by the parameters of the resistivity of reaction resistance and the double layer capacitance in an equivalent circuit.