New accelerated charge methods using early destratification applied on flooded lead acid batteries

A traditional charge process for flooded lead acid batteries (FLABs) lasts generally from 8 to 14 h. Nowadays, many applications of FLABs require reduction of the charge duration, for instance, a 4 h-charge for FLABs in grid energy storage or 1 h-charge for FLABs in electric buses. These are called accelerated charge and fast charge. Such reductions of charge time imply the use of a new charge process. One way to reduce the charge duration is to perform an early destratification step without waiting for the end of charge. The new charge method proposed in this paper (early destratification method – ED) focuses on the reduction of the charge time for FLABs using early destratification, which is performed and controlled using charge acceptance measurement during the charge. Laboratory experiments presented here aim first to develop charge acceptance measurements followed by an ED charge method compared to an IUi traditional charge process.

Research highlights▶ A new charge method is proposed for fast charges and accelerated charges of flooded lead acid batteries using early destratification with charge acceptance measurements. The modification of a “12 h” charger with an algorithm of the early destratification enables the battery to be available for a discharge in duration of the order of 4–6 h. This division of the charge duration of a factor two is obtained without increasing the charger power.