When the battery is charged and discharged, electrochemical reactions occur on the battery electrodes. The higher the temperature, the activity of each active material in the battery increases, the viscosity of the electrolyte decreases, and the resistance decreases. Therefore, the electrochemical reaction is easy to proceed, and vice versa. . The lower the temperature during discharging, the lower the discharge capacity. At a particularly low temperature, the discharge capacity will drop significantly, but the opposite is true when the temperature is high; the lower the temperature during charging, the worse the charge acceptance capability, and a higher charging voltage is required to be sufficient. Electricity. Conversely, the higher the temperature, the better the charge acceptance, which is likely to cause overcharging. Therefore, it is required to lower the charging voltage to avoid overcharging. This temperature change directly affects the charging and discharging performance of the battery.