Visible to Intel only — GUID: dmi1457533713937
Ixiasoft
Visible to Intel only — GUID: dmi1457533713937
Ixiasoft
1.3.2. BMS Reference Design Battery Model
The only input is the battery current, which is the same for all the series-connected cells. For the output, at each time step, the model generates the arrays of the cell voltages V i, SOC, and the current values of the model parameters.
The left hand side models the cell capacity Q n and evaluates the SOC as the voltage across a linear capacitor with a capacity equal to Q n (expressed in Coulomb) divided by 1V. The cell voltage v M is the sum of the open-circuit voltage V OC and a dynamic term, which accounts for the internal Ohmic resistance R 0 and the double layer effect (V RC1 ) and diffusion (V RC2 ) of the Li-ion during charging and discharging (two RC branches). The model parameters change with manufacturing variations, ageing and operating conditions, such as temperature and state of charge. To model the temperature and SOC dependences, the reference design stores the parameter values in two-dimensional LUTs. You see the variability of the cell behaviour by setting the model parameters, temperature, and capacity of each cell individually