2. Phosphoric acid The addition of phosphoric acid to the electrolyte of lead/acid batteries has been practised since the 1920s [59]. The main motivations were reduction of sulfation (espe- cially in the deep-discharge state) and extension of cycle life by reduced shedding of positive active material.
Reversible capacity loss, which occurs after extended cycling and when pulsed discharge is applied, can be recovered by a single discharge at very low rate with batteries with and without the addition of phosphoric acid. The discharge-rate dependency of the capacity is significantly reduced when phosphoric acid is added.
The addition of phosphoric acid to the electrolyte may be helpful for EV batteries due to several reasons: The cells are more tolerant with respect to (low) initial recharge rates (memory effect).
Influence of phosphoric acid additiue Phosphoric acid addition reduces the sensitivity of the actual battery capacity on the recharge scheme. This is especially true for the influence of the initial recharge current, which is a emory effectphenomenon.
The influence of the addition of phosphoric acid to the electrolyte on the performance of gelled lead/acid electric-vehiicle batteries is investigated. This additive reduces the reversible capacity decay of the positive electrode significantly which is observed upon extended cycling when recharge of the battery is performed at low initial rate.
When the data in Figs. 5 and 6 are 125 Ah appears to be characteristic for pulsed discharges compared, it is obvious that the cell voltage under pulse of batteries with phosphoric acid additive, i.e., when the load is higher and the voltage drop at the beginning of a recharge schemes 15 Uor I 15are applied.