In the charge and discharge system, along with the charging and discharging process, the battery's capacity i.e. SOC changes. At present, the related parameters of the battery's SOC have low accuracy, and the battery R&D engineers are also trying their best to improve the battery SOC's accuracy. The SOC parameter of the battery is usually calculated from the charging and discharging time or the internal impedance of the battery. However, considering SOC is also a parameter that reflects the change of internal battery power, that is, the charge and discharge process is also the process of battery energy injection and release. In order to obtain the parameters for battery injection and release, we introduced a test method for high-precision current sensors and power analyzers. Compared with traditional charge-discharge systems, the power analyzer can not only test the voltage, current, and power of both ends of the battery. It is also possible to integrate the measured values (see Figure 1) to obtain the energy parameters injected into the battery or battery during a period of time, which can help the battery R&D engineer to more accurately calculate the battery SOC variation.