Influence of charge mode on the capacity and cycle life of lead–acid battery negative plates

Abstract

The effect of fast and three-step charge mode on the capacity and cycle life of lead–acid battery negative plates was investigated using a model mini electrode (ME). It has been found that the charge algorithm exerts a strong effect on the charge acceptance of the negative electrode. In the two-step charging mode I 1, ϕ 2 with increase of the current at the first step of charge, the capacity of the negative electrode decreases and the cycle life shortens. This phenomenon is reversible as it is probably due to the incomplete reduction of PbSO 4 to Pb. The phenomenon is explained based on the mechanism of the process of reduction of PbSO 4. At high initial charge currents, the concentration of H 2SO 4 in the pores of NAM increases, which decreases the solubility of PbSO 4 crystals and limits the charge acceptance of the negative plate. The higher initial charge current influences markedly the formation of smaller Pb crystals that build up the energetic structure of the negative active material. It is essential that a third step with a small constant current, I 3 is added to the charge algorithm. The third step of charge in the I 1, ϕ 2, I 3 charge mode decreases the Ohmic resistance and ensures complete charge of the lead electrode.