Sulphuric acid concentration determination method for batteries

摘要

The concentration of sulphuric acid in a lead-acid battery is a direct measure of the state of charge of that battery. The method involves using a sensor (1), which consists of three electrodes, for measuring the concentration. The measurement electrode (2) of an electrochemically active material, such as lead or lead oxide, and the bipolar counter electrode (3) are placed into the battery acid, and the reference electrode (6), is immersed in a cell containing a known concentration of sulphuric acid (13). The lead counter electrode is in contact with the reference acid at its top end. When the battery is fully charged the potential between the measurement and the reference electrode is zero.