Soaking of 3BS-cured pastes

The changes in PbO and PbS04 content in the paste (determined by wet analysis) during soaking of the positive plates are presented in Fig. 3.5. Similar changes in chemical composition have also been observed with the negative plates. After 8 h, the amount of PbS04 in the positive paste increases by 22,47, and 60% for acid solutions of 1.05, 1.15, and 1.25 rel. dens., respectively. 

The data in Figs. 3.4 and 3.5 indicate that despite the presence of PbO and H2SO4 the reaction between them proceeds at a very low rate. Our recent investigations have provided an explanation for this phenomenon. It has been found that in the plate 

The above electron micrographs of soaked pastes indieate that PbS04 crystals retain no memory of the initial 3BS crystals, which has also been reported by other researchers [8,9]. On the other hand, the mierographs in Fig. 3.6 show that considerable quantities of 3BS crystals remain unsulfated even after 5 h of soaking in H2SO4 of 1.25 rel. dens., i.e., there is a traee of memory of the initial paste composition. The remaining 3BS crystals are involved in the proeesses of formation and exert an influence on the organization of the PAM strueture, and hence on the performance of the battery. 

The cycle-lives of the above batteries under the DIN 43539/2-test protocol for automotive batteries are presented in Fig. 3.9. The end-of-discharge voltage at the tenth charge-discharge cycle (i.e., after one week of cycling) is given in Fig. 3.9(a), and the voltage after 30 s of the CCA test in Fig. 3.9(b). The batteries were soaked 

It has been established that the processes of soaking are alfected by the density of the 3BS paste. Thus, at a paste density of 3.89gcm , the amount of H2SO4 that reacts during the soaking step is greater than that for pastes with density 4.39 gcm [5]. 

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