Influence of Crystal Control Technology® on the operation of lead batteries
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.
Boris Monahov has 43 years of experience in battery science, technology, and development. He holds a degree in solid-state physics form the University of Sofia, as well as a PhD in electrochemistry of electrochemical power sources from the Bulgarian Academy of Sciences, and habilitation in the same field with the team of Prof. Pavlov.
His carrier comprises 25 years of academic research on lead-acid batteries and technology development under the guidance of Prof. D. Pavlov at the Bulgarian Academy of Sciences, the last 10 years as Associate Professor and project manager. After moving to the USA in 2004, he spent 5.5 years in the battery industry as Chief Electrochemist of Firefly Energy, a Caterpillar spin-off for carbon-foam batteries in Illinois. This was followed by 9 years of international R&D management as Program manager of the ALABC, the global research organization of the lead battery industry based in the USA and managed by ILA in London. In this period, he supervised 40 international R&D projects in the USA, Europe and Asia focused on the hottest topics of lead battery innovation.
Since 2019 Boris serves as Chief Scientific Officer of WaveTech International company with offices in the USA, Germany, Bulgaria, and Turkey.
He has over ninety scientific articles with more than eight hundred citations, and five patents on lead batteries, as well as several presentations at main international battery conferences during the last 25 years.
Awarded by the Gaston Plante Medal and member of the alpha-beta Society.