The use of energy storage lead acid batteries in deeper discharge leads to a pronounced capacity fading and too short life. Now the analysis of positive active material (PAM) composition was the average content of plates. So exploring the influence of positive additives to PAM and cycle life in lead acid batteries was very limited. In addition, the cycle life test of lead acid batteries, especially at relatively high depth of discharge (DoD) could continue for months, even years. It’s always a challenge to the efficiency of research and development of new products. In our work, plates with different DoD have been divided into five layers from surface to center of section. The content of PbO₂ in above samples have been characterized by X-ray diffraction (XRD). The reaction depth index of Plates has been obtained by Gaussian fitting of PbO₂ content distribution curves of section direction. Addition of metallic sulfate and metallic oxide into the active mass of positive electrode clearly extended the cycle life of batteries. Through contrastive analysis of different lead acid batteries, it has been established that lower reaction depth index was beneficial for the cycle life of batteries. Upon the relationship between reaction depth index and cycle life of lead acid batteries, the cycle life of new battery could be predicted accurately.

Fig.1 the relationship of DoD, reaction depth index and cycle number