High precision coulometry in the determination of the state-of-health of Li-ion batteries

U ovome radu praćeno je ponašanje Li-ion galvanskih članaka tijekom cikliranja metodama kulometrije visoke preciznosti i elektrokemijske impedancijske spektroskopije (EIS). Ove metode pokazale su se uspješnima za predviđanje životnog vijeka članaka, te praćenja stanja zdravlja i stanja napunjenosti. Određene su i grafički prikazane kulonska učinkovitost tijekom 10 ciklusa, te impedancija članka prije cikliranja i nakon završetka cikliranja. Usporedba impedancijskih krivulja pokazala je da tijekom cikliranja dolazi do smanjenja brzine prijelaza elektrona i otežane difuzije. Dokazano je da su neželjene parazitske reakcije prisutne u člancima prilikom rada.In this work, the behavior of Li-ion galvanic cells while cycling was monitored by high precision coulometry and electrochemical impedance spectoscropy (EIS) methods. It was shown that these methods are effective for predicting the life span of galvanic cells, and for the monitoring of State of Health (SoH) and State of Charge (SoC). Coulombic efficiency was determined and graphically shown, as well as the cell impedance before and after cycling. The comparison of the two impedance spectra showed that the decrease of the rate of electron transfer and diffusion occurs. It has been proved that parasitic reactions are present in cells when running