The battery is an indispensable and important part of the DC power supply system.
The role of the battery in the system is mainly as an energy storage device. When the external AC power supply is suddenly interrupted, the normal operation of the communication equipment will be threatened, and the battery is used as a backup protection for the system power supply, which can provide 1 to 20 hours or more. Uninterruptible power supply.
Therefore, as the last guarantee for system power supply, the battery is also the last guarantee for maintaining normal communication.
The battery is composed of positive and negative plate groups, electrolyte and battery tank. The active material on the positive plate is lead dioxide (PbO2), and the active material on the negative plate is spongy lead (Pb). The electrolyte is made of distilled water and pure sulfuric acid in a certain proportion.
When the electrolyte of a certain density is filled in the electrolytic cell, the active material on the positive and negative plates begins to undergo a series of chemical reactions with the electrolyte, and a potential difference of 2.1V is formed on the positive and negative plates, which is the voltage of the battery. Electromotive force (E). Therefore, when the battery is being charged, the voltage of the external DC power supply should be higher than the electromotive force of the battery.
The overall electrochemical reaction during battery discharge is:
During the discharge process of the battery, the active substances on the positive and negative plates are continuously transformed into PbSO4. Due to the poor conductivity of lead sulfate, the internal resistance of the battery increases after discharge. In addition, during the discharge process, since the lead sulfate in the electrolyte gradually turns into water, the density of the electrolyte gradually decreases. Therefore, the internal resistance of the battery increases and the electromotive force decreases. When the discharge ends, the terminal voltage of the battery drops to about 1.8V.
The overall electrochemical reaction during battery charging is:
During the charging process, the density of the electrolyte gradually increases, and the electromotive force of the battery gradually increases. In the later stage of charging, most of the active substances on the plate have been reduced. If you continue to charge with a high current, the charging current can only play the role of splitting water. In this way, a large amount of hydrogen gas will escape from the negative plate, and a large amount of oxygen gas will escape from the positive plate, resulting in severe outgassing from the battery.