Field experience with reference electrode measurements

All battery users want to assess the state of their cells on a regular basis. Although capacity testing is the proven method of assessment, capacity tests are not intended to be completed during every battery inspection. One technique that has been used in the laboratory since early in the conception of voltaic cells is the use of a reference electrode. The reference electrode measurement allows the evaluation of the positive plate and the negative plate separately. Cell life is usually limited by the positive plate grid corrosion. The corrosion rate of the positive grid is directly affected by the polarization of the positive plate under float. Although the corrosion of the negative grid does not occur, it is important for the negative plate to be polarized to some extent. If the negative is depolarized, the capacity of the negative plate will be reduced. This may result in the cell being negative plate limited which will effectively reduce the capacity of the battery even if the positive plate is in an acceptable condition. This paper presents plate polarization data using the reference electrode and compares these results to actual capacity data and other measured parameters for lead-acid batteries.