（1） Positive plate (positive active material)
The main component of the active material of the positive plate is lead dioxide, which has strong oxidizability. When discharging, it reacts with sulfuric acid to form lead sulfate, and absorbs electrons. There are two types of lattice of lead dioxide, one is lead oxide α— The other is PB02 β— PB02. These two lead dioxide active materials are very different, and they play different roles in the positive plate ß— The capacity given by PB02 is α— 1.5 ~ ~ ~ 3 times of PbO2 α— PB02 has good mechanical strength. The active material of positive plate is not suitable to soften and fall off due to the existence of PB02 α— PB02 and βα— When the ratio of PbO 2 reaches 0.8, lead-acid battery will show good performance
The reaction equation is as follows: PB02 + 3H + + HSO4 + 2E = = PbSO4 + 2H2O, when charged, it is converted to lead sulfate under the action of external circuit ρ The results show that when the O2 and H2SO4 are discharged, the content of PbO2 is higher than that of PbO2 ρ B4 + is formed by electrons from the negative electrode ρ B + 2 is formed by combining with sulfate ion in solution ρ Bso4. When lead sulfate reaches a certain amount, it becomes precipitate and adheres to the electrode plate. During charging, the electrons of lead ions in lead sulfate are taken away by the external circuit and converted into lead dioxide. Hydrogen ions in water are left in the solution. Oxygen ions combine with lead ions to form lead dioxide into the lattice and form a positive active material
（2） Negative plate (negative active material)
In lead-acid batteries, in order to make the negative active material fully react with the electrolyte, lead is made into porous sponge shape, also known as sponge lead. During discharge, lead gives out external circuit electrons to form Pb + 2, which combines with sulfate in solution to form lead sulfate. During charging, part of PbSO4 first dissolves into Pb2 + and SO4. Pb + 2 receives electrons to reduce into lead and enters the lattice of negative active material.
（3） Electrolyte
Sulfuric acid is one of the important raw materials in the electrolyte of lead-acid batteries. There are two kinds of concentrated sulfuric acid in the market: one is industrial concentrated sulfuric acid with low purity, which is not suitable for lead-acid batteries; The molecular weight of sulfuric acid is 98%, and the content of sulfuric acid in concentrated sulfuric acid is 98%. It is colorless and transparent oily liquid with strong water absorption and corrosiveness. When combined with water, it can release a lot of heat. Therefore, in the process of electrolyte preparation, we must pay attention to protection to avoid danger. When preparing, do not add water into concentrated sulfuric acid, Instead, add concentrated sulfuric acid to the water slowly. In the preparation process of lead-acid battery electrolyte, the requirement for water is high. The amount of impurities in the water directly affects the quality of the battery. The appearance of lead-acid battery water is colorless and transparent, and the residue content should be less than 0.01%（ Ω The simple method is: using resistivity measurement method: using digital multimeter to set the gear to 20m Ω The distance between the two probes of the multimeter is 1cm, and the measured resistance is 5-10m Ω That's it.
（4） Clapboard
Separator is also one of the main components of lead-acid battery, and its quality has a great impact on the battery. The main function of separator is to prevent short circuit between positive and negative plates of battery. In battery, the requirements for separator are as follows: porous separator is used to allow free diffusion of electrolyte and ion migration, with relatively small resistance, small pore diameter of separator, large total area of gap, and high resistance, Therefore, the pore size of the separator should be smaller and the number of pores should be more.
