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CV Measurement Experimentation Regarding the Effects of Adding the Equaliser on Sulfation
Figure 1: Behaviour of electricity charge/discharge at the positive and negative electrodes in diluted sulfuric acid
Figure 2: Electricity charge/discharge curves on the positive electrode side of the lead-acid battery (First cycle)
We
swept the positive electrode (PbSO4), for which discharge conditioning
has been performed, from the initial voltage of 0.5 V to 1.8 V. As a
result, the oxidation wave peak emerged at around 1.6 V. This is a
clear indication of the charge reaction (PbSO4 → PbO2 : peak height
represents the amount of charge) being in progress on the positive
electrode side. After sweeping as far as 1.8 V, we returned the
electric potential to 0.5 V. In this process, the discharge reaction
(PbO2 → PbSO4) took place as expected. During the first cycle, the
oxidation wave peak (charge peak) and the reduction wave peak
(discharge peak) emerged prominently.
Figure 3: Electricity charge/discharge curves on the positive electrode side of the lead-acid battery (Sixth cycle)
Likewise,
we repeated the charge – discharge operation over six cycles.
Subsequently, the oxidation wave peak (charge peak) and the reduction
wave peak (discharge peak) could no longer be confirmed. This means
that the positive electrode side is not charging or discharging
electricity (sulfation).
Figure 4: Electricity charge/discharge
curves on the positive electrode side of the lead-acid battery (Sixth
cycle + Equaliser added)
We added the equaliser to the
solution that has no charge or discharge activity, and measured CV
under the same conditions. The result showed a wave form almost
identical to that shown in the graph in Figure 2. This means that the
positive electrode that was inactive and not charging has become a
chargeable active material and that the equaliser would have caused
that effect.
Figure 5: Electricity charge/discharge curves on
the positive electrode side of the lead-acid battery (Sixth cycle + Six
cycles after adding the equaliser)
After adding the equaliser and repeating charging and discharging of electricity over six cycles, it became inactive.
This means that, in extending the life of the positive electrode side, the equaliser solution does not work so effectively.
Figure 6: Electricity charge/discharge curves on the negative electrode side of the lead-acid battery (First cycle)
We
swept the negative electrode (PbSO４), for which discharge conditioning
has been performed, from the initial voltage of -0.1 V to -1.8 V. As a
result, the reduction wave peak emerged at around -0.5 V. This is a
clear indication of the charge reaction (PbSO4 → Pb : negative height
of the peak represents the amount of charge) being in progress on the
negative electrode side. After sweeping as far as -1.8 V, we returned
the electric potential to -0.1 V. In this process, the discharge
reaction (Pb → PbSO4) should progress. During the first cycle, the
oxidation wave peak (charge peak) and the reduction wave peak
(discharge peak) emerged prominently.
Figure 7: Electricity
charge/discharge curves on the negative electrode side of the lead-acid
battery (Sixth cycle + Equaliser & Sixth cycle)
During the
first cycle, the oxidation wave peak (charge peak) and the reduction
wave peak (discharge peak) emerged prominently. During the sixth
charge/discharge cycle, little variation (from the first cycle) was
seen in the oxidation and reduction waves. Therefore, based on this
experiment, the effects of charge/discharge on the negative electrode
side have little to do with the overall inactivity of lead-acid battery.
Figure 7(sic.): Electricity charge/discharge activity and capacity of the overall lead-acid battery system
Addition of the equaliser has a significant effect on the activity of overall lead battery system, also.
Summary
1) The battery equaliser has an effect of reactivating an electrode that lacks charge activity.
2) It also has a sufficient capability to reactivate the overall lead-acid battery system.
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