The basic principle of battery energy storage relies on chemical reactions through which the battery is able to store and release electrical energy.
Batteries usually consist of a positive and a negative electrode, and between the two poles contain substances that carry out chemical reactions. During the charging process, the negative electrode is oxidized to release electrons, while the positive electrode is reduced to absorb electrons. This process causes the negative electrode to be negatively charged and the positive electrode to be positively charged. When the positive and negative electrodes of the battery are connected by an external wire, the electrons generated by the chemical reaction flow from the negative electrode to the positive electrode, forming an electric current. During discharge, electrons flow in the opposite direction, and the stored chemical energy is converted into electrical energy. The electromotive force of a battery determines how much energy it stores. As the internal reaction of the battery proceeds, the chemical substances are gradually consumed, and the battery voltage decays until it is fully discharged. Charging is the process of restoring the chemical energy of a battery by forcing the flow of electrons in the opposite direction. The secondary battery achieves repeated charging and discharging through reverse electrochemical reaction.
In addition, the battery Management System (BMS) is responsible for monitoring the status of the battery, protecting the battery from overcharge or overdischarge, and ensuring the efficient use of electrical energy. The Energy Management System (EMS) is responsible for data acquisition, network monitoring and energy scheduling. The energy storage converter (PCS) controls the charging and discharging process of the battery pack for AC/DC conversion