Method of Estimating Deterioration of Lead‐Acid Batteries Using Pulse Discharge and Charge Characteristics

Abstract Lead‐acid batteries have been used as emergency back‐up power supplies for communication systems. These batteries usually are charged and provide power to communication systems when a power blackout occurs. If the communication system is out of order during the blackout, the problems can be enormous. Therefore, NTT has been serious about the maintenance of the lead‐acid batteries. Since it takes longer than 20 hours to check the capacity of a battery, some other convenient battery evaluation method must be established. In this paper, the degradation mechanism of the lead‐acid battery was studied and it was concluded that the degradation of the internal resistance is related strongly to the capacity degradation. By measuring the internal resistance, the charge/discharge characteristics were evaluated for a short period of time. It was confirmed also that the internal resistance measured by measuring the charge/discharge characteristic for a period shorter than 500 ps is related strongly to the battery capacity. Using the forementioned relationship, the battery degradation was determined.