Influence of Crystal Control Technology® on the operation of lead batteries

The Crystal Control Technology® of WaveTech uses a specifically modulated electric signal which is sent to the battery through the terminals. The signal provides extra energy to the charge carriers what in turn changes the ionic kinetics and the structure of the electric double layer formed on the surface of the positive and negative plates. Dissolution, nucleation, and growth of crystals in the interface electrode/electrolyte is optimized. More uniform crystals are formed, and the concentration polarization is reduced.

Recent studies have shown that CCT® enhances the crystal dissolution and precipitation reactions in lead-acid batteries so that formation is accelerated (by up to 15%) and becomes more efficient. The capacity of formed by CCT batteries can increase up to 30%.

Another effect is the increased stability of the porous microstructures of both positive and negative active materials (PAM and NAM) where the capacity is born. The microstructures need to self-rebuild on cycling to ensure longer battery lifey. Left to themselves, the active mass microstructures deteriorate on cycling what is one of the main reasons for capacity loss. CCT® enhances the self-maintaining of the microporous crystal structures in both active materials. As a result, batteries operating with CCT® can have up to twice longer service life. The way the NAM and PAM microstructures change on cycling under the action of CCT® are different. Specific changes in the NAM microstructure were observed by combining reference electrodes with material science methods.

Two more beneficial effects of CCT® have been observed by testing of commercial VRLA batteries:

1) The rate of hydrogen evolution and the flow rate of gas leaving the cells of brand new commercial batteries on overcharge is slowed down by CCT®. The effect on oxygen evolution is smaller. The conclusions are based on polarization studies combined with Electrochemical Impedance Spectroscopy (EIS) and Gas Evolution Analyses (using the eGAS device of MeasX GmbH developed in Germany with support of CBI). The reduced gassing rate is related to the changes in charge transfer resistance and double layer capacity observed for both reactions.

2) Under the influence of CCT®, the charge acceptance of VRLA cycling batteries increases. The effect depends on battery size, as well as on temperature. The improvement increases at low temperature where the mobility of the charge carriers is reduced, and the power performance of batteries is low. The average cycle time for 10 cycles with CCT® declines by 25% at 40 deg C, by 35% at 25 deg C and by 50% at 10 deg C. The duration of charge is reduced for every cycle, while discharge time remains constant. This effect offers an affordable way to improve the performance of storage batteries at low temperature.

Lead-acid battery power performance is determined by both Faradaic reactions and electric double layer (EDL) charge processes. CCT® influences the rapid EDL processes, but also the Faradaic reactions based on crystal dissolution, nucleation and growth, which processes control the building of the microporous active mass structure.

The size of the effect depends on the ratio between the rates of both processes, the specific surface area of the positive and negative plates, the transportation limitations in the fine pores of PAM and NAM, as well as on the local electrolyte concentration and material transfer limitations near the reaction sites.

Battery testing with CCT® devices has always demonstrated a beneficial effect on operating batteries. This effect can be maximized by CCT® calibration and adaptation to the battery design and size, as well as to the battery operating conditions in the application.