Note that both Gel and AGM are often simply referred to as Sealed Lead Acid batteries. The Gel and AGM batteries are a variation on the flooded type so we''ll start there. Structure of a flooded lead acid battery …
When the lead acid battery is discharging, the active materials of both the positive and negative plates are reacted with sulfuric acid to form lead sulfate. After discharge, the concentration of sulfuric acid in the electrolyte is decreased, and results in the increase of the internal resistance of the battery.
The technical challenges facing lead–acid batteries are a consequence of the complex interplay of electrochemical and chemical processes that occur at multiple length scales. Atomic-scale insight into the processes that are taking place at electrodes will provide the path toward increased efficiency, lifetime, and capacity of lead–acid batteries.
Despite competition from Li-ion batteries, LA batteries still enjoy a large market share in utility applications and even in the current smart grid infrastructure . The LA battery used in this paper will be referred as Sealed Lead Acid (SLA) cells.
Reactions of Sealed Lead Acid Batteries When the lead acid battery is discharging, the active materials of both the positive and negative plates are reacted with sulfuric acid to form lead sulfate.
1. Construction of sealed lead acid batteries Positive plate: Pasting the lead paste onto the grid, and transforming the paste with curing and formation processes to lead dioxide active material. The grid is made of Pb-Ca alloy, and the lead paste is a mixture of lead oxide and sulfuric acid.
3.3 Battery Self-discharge The lead acid battery will have self-discharge reaction under open circuit condition, in which the lead is reacted with sulfuric acid to form lead sulfate and evolve hydrogen. The reaction is accelerated at higher temperature. The result of self-discharge is the lowering of voltage and capacity loss.