The working voltage of the battery is used as the ordinate, discharge time, or capacity, or state of charge (SOC), or discharge depth (DOD) as the abscissa, and the curve drawn is called the discharge curve. To understand the discharge characteristic curve of a battery, we first need to understand the voltage of the battery in principle.
The lithium battery discharge curve is a curve in which the capacity of a lithium battery changes with the change of the discharge current at different discharge rates. Specifically, its discharge curve shows a gradually declining characteristic when a lithium battery is operated at a lower discharge rate (such as C/2, C/3, C/5, C/10, etc.).
Polarization curves Battery discharge curves are based on battery polarization that occurs during discharge. The amount of energy that a battery can supply, corresponding to the area under the discharge curve, is strongly related to operating conditions such as the C-rate and operating temperature.
Step 1: Carry out the cycle charge and discharge experiments of Li-ion batteries and obtain the characteristic curves of each cycle by data calculation. Step 2: Perform curve smoothing on the battery characteristic curve.
The slope of the lithium battery charging curve reflects the fast charging speed. , the greater the slope, the faster the charging speed. At the same time, the platform area of the lithium battery charging curve indicates that the battery is fully charged, and the voltage tends to be stable at this time.
This factor dominates as a Li-ion battery is fully discharged, where the slope of the curve becomes very steep. Polarization curve (discharge curve) of a battery shows the cumulative impact of the IR drop, Activation polarization, Concentration polarization on Vt (cell potential). (Image: BioLogic) Discharge curve considerations