A data-driven coulomb counting method is proposed to estimate state of charge (SOC) of lithium-ion battery. The incremental capacity analysis method without filtering process is applied to calibrate the initial SOC value. The Gaussian process regression (GPR) method is used to calibrate the actual capacity.
It is usually expressed in milliamp-hours (mAh) or ampere-hours (Ah). By integrating the lithium battery charge curve and discharge curve, the actual capacity of the lithium battery can be calculated. At the same time, multiple charge and discharge cycle tests can also be performed to observe the attenuation of capacity.
Experimental results show that this method can effectively measure the actual voltage of lithium-ion battery under different rated voltages, and the measured voltage waveform is very stable and almost without distortion.
The lithium battery charging curve illustrates how the battery’s voltage and current change during the charging process. Typically, it consists of several distinct phases: Constant Current (CC) Phase: In this initial phase, the charger applies a constant current to the battery until it reaches a predetermined voltage threshold.
The standard regimen for charging lithium-ion cells is CCCV charging. The charging DC source is set to the desired charging current rate and voltage level set to equal to the cell’s fully charged voltage. This gives a rectangular I-V characteristic plot for the positive quadrant, like that previously shown in Figure 1, now shown in Figure 3.
As one of the key testing indexes for the performance of lithium battery, the testing of charging and discharging characteristics can directly show the capacity and performance of lithium battery. The advantages of lithium battery mainly have no pollution, no memory and large monomer capacity, which are widely used in various electronic products.