Python script for linear approximation of battery SOC based on voltage measurement only. Scripts inputs battery cell voltage measurement during constant current discharge.
Select number of points to perform linear approximation at the start of sript:
# Find points at certain voltage
# NOTE: In decending value as acquire by measurement
VOLT_POINT = [ 4.13, 3.66, 3.40, 3.25, 2.5 ]
VOLT_POINT_EPS = 0.005User can change "VOLT_POINT" array, remove or add additional point for interpolation.
All script requirements are listed in requirements.txt
Install it via pip:
>>>pip install -r requirements.txt>>>py bat_soc_est.py -f meas_data\200mA_27.05.2021_working.csvCalculated linear coefficients and inital value for given example (as pairs):
k: [0.9333726963064314, 1.7743934458548243, 0.4711244213113143, 0.037018631374283406]
n: [-2.8556498619062087, -5.9337858052533266, -1.5026711218053928, -0.09182730451004238]
# Use it as between specified voltage range (look at the sript configuration)!
SoC(cell_vol) = k * cell_vol + n
# Where output is in range from 0 - 1.0!-
FIRST PLOT: Cell voltage and current during constatn current (CC) discharge.
-
SECOND PLOT: Yellow dashed line is interpolation of battery SOC and yellow points are specified as sript configuration. Green line is actual SOC level in respect to cell voltage during CC disharge.
