The lead-acid battery is one kind of storage battery. With its low price and good high-rate discharge performance, it is very widely used; cars, motorcycles, trains, ships, communications, and UPS all need lead-acid batteries. So do you know the principle and process of lead-acid battery repair? Today we introduce it, let us take a look.

A lead-acid battery consists of a positive plate group, a negative plate group, an electrolyte, and a container. The positive plate is brownish lead dioxide (PbO2), and the negative plate is gray spongy lead (Pb). When the two plates are placed in a sulfuric acid (H2SO4) aqueous solution with a concentration of 27%-37%, the lead on the plates reacts chemically with the sulfuric acid: divalent lead ions (Pb2+) move into the electrolyte, leaving two electrons (2e-) on the negative plate. Due to the attraction of positive and negative charges, lead ions gather around the negative plate, while in the positive plate a small amount of lead dioxide (PbO2) seeps into the electrolyte under the action of water molecules; its divalent oxygen ions combine with water, turning the lead dioxide molecules into an unstable, dissociable substance, lead hydroxide [Pb(OH4)].

Lead hydroxide consists of tetravalent lead ions (Pb4+) and four hydroxide ions [4(OH)-]. The tetravalent lead ions (Pb4+) remain on the positive plate, making it positively charged. Because the negative plate is negatively charged, a potential difference arises between the two plates, which is the electromotive force of the battery. When an external circuit is connected, current flows from the positive to the negative plate. During discharge, electrons on the negative plate continually flow through the external circuit to the positive plate; meanwhile, in the electrolyte the sulfuric acid molecules ionize into hydrogen ions (H+) and sulfate ions (SO42-), and under the ionic electric field the two kinds of ions move toward the negative and positive plates respectively. When sulfate ions reach the negative plate they combine with lead ions to form lead sulfate (PbSO4). On the positive plate, electrons flowing in from the external circuit combine with tetravalent lead ions (Pb4+) to form divalent lead ions (Pb2+), which immediately combine with nearby sulfate ions to form lead sulfate that adheres to the positive plate

Through this introduction, we believe you now have some understanding of the principle and process of lead-acid battery repair, and we hope it has been of some help.