There are two major types of lead–acid batteries: flooded batteries, which are the most common topology, and valve-regulated batteries, which are subject of extensive research and development [4,9]. Lead acid battery has a low cost ($300–$600/kWh), and a high reliability and efficiency (70–90%) .
Lead–acid batteries were used to supply the filament (heater) voltage, with 2 V common in early vacuum tube (valve) radio receivers. Portable batteries for miners' cap headlamps typically have two or three cells. Lead–acid batteries designed for starting automotive engines are not designed for deep discharge.
Lead–acid batteries consist of a metallic lead (Pb) negative electrode, a lead dioxide (PbO 2) positive electrode, and a sulfuric acid electrolyte. The overall cell reaction is The voltage of lead–acid cells on open circuit is approximately 2 V; a standard 12-V (SLI) battery therefore consists of six individual cells connected in series.
The lead–acid battery is a type of rechargeable battery first invented in 1859 by French physicist Gaston Planté. It is the first type of rechargeable battery ever created. Compared to modern rechargeable batteries, lead–acid batteries have relatively low energy density. Despite this, they are able to supply high surge currents.
As low-cost and safe aqueous battery systems, lead-acid batteries have carved out a dominant position for a long time since 1859 and still occupy more than half of the global battery market [3, 4]. However, traditional lead-acid batteries usually suffer from low energy density, limited lifespan, and toxicity of lead [5, 6].
In 1992 about 3 million tons of lead were used in the manufacture of batteries. Wet cell stand-by (stationary) batteries designed for deep discharge are commonly used in large backup power supplies for telephone and computer centres, grid energy storage, and off-grid household electric power systems.