Photovoltaic engineers and technicians should understand the electrochemical principles of lead-acid batteries. At the very least, they must know: 1. What is the composition of the positive and negative plates of the lead-acid battery, and what are the active materials in the electrolyte; 2. What is the discharge process What substance is produced by the substance, what substance is produced by the charging process; 3. What side reactions occur in addition to the positive reaction during the charging and discharging process, and what harm will the side reaction cause. The typical electrochemical reaction equation of lead-acid battery is as follows:
There should be no side reactions during the charging process. These two side reactions are not caused by overcharging, but by insufficient charging at low temperatures. The long-term undercharge of the battery at low temperature will damage the battery as much as it is overcharged! Therefore, when designing the photovoltaic system configuration, it is better to design the solar cell components larger than that of the battery every day! From the above The electrochemical reaction formula shows that the battery charging process is an electrochemical reduction reaction. The active material in the electrolyte increases in pure sulfuric acid concentration, that is, the active material is reduced; the battery discharge process is an electrochemical oxidation reaction, and the sulfuric acid in the electrolyte is consumed. As a result, the active material concentration is reduced. When the battery reaches a certain level, the battery reaches the end voltage point, and the discharge should be stopped.