Lead Acid Batteries
It is still the battery chemistry with the highest turnover worldwide
They are most commonly used as starter batteries for motor vehicles. In addition to that there is a wide variety of applications, such as in UPS systems, submarines, storage for solar arrays, electric wheelchairs, and forklifts.
Reliability, availability, and profitability due to low costs are important factors in their use. However, the cost effectiveness of lead acid batteries is increasingly questioned because of falling costs for other battery systems, especially since robust lithium iron phosphate batteries are now available. In contrast to lithium batteries, however, lead acid batteries have the advantage of not requiring a battery management system to monitor the battery cells. Storage systems with a lead acid battery can therefore (still) be offered at a cheaper price than systems with a rechargeable lithium battery.
The nominal voltage of a cell is 2 V. However, the voltage fluctuates depending on the charge status and charge or discharge current between about 1.75 and 2.4 V. Lead acid batteries should never be fully discharged (cell voltages below 1.8 V), since this can render them unusable.
The commonly used batteries have a voltage of 6V and 12V. Accordingly, many cells are connected in a battery. A lead acid battery consists of an acid-resistant housing and two lead plates or groups of plates, one of which serves as positive and the other as a negative polarized electrode, and a filling of 37-percent (H2SO4) as an electrolyte. In the commercial version, the electrode plates are nested tightly next to one another and the separators are located in between, made for example from perforated, corrugated polyvinyl chloride (PVC), which prevents a direct contact between them (short circuit). The connectors and connection plates are made of metallic lead in starter batteries, for example. In discharged or neutral state a layer of lead (II) sulfate (PbSO4) gets deposited on two electrodes groups. In charged state, the positive electrodes consist of lead (IV) oxide (PbO2) and the negative-pole electrodes of finely spread, porous lead (spongy lead).
Lead acid batteries can reach quite a high service life of several years.