Code covered by the BSD License

Lithium Battery Model, Simscape Language and Simulink Design Optimization

Robyn Jackey (view profile)

19 Apr 2012 (Updated )

Multi-temperature lithium battery model using Simscape language and Simulink Design Optimization

ssc_lithium_cell_2RC_ini.m
```% Initialization file for demo ssc_lithium_cell_2RC.mdl. Demo
% based on T. Huria, M. Ceraolo, J. Gazzarri, R. Jackey. "High Fidelity
% Electrical Model with Thermal Dependence for Characterization and
% Simulation of High Power Lithium Battery Cells," IEEE International
% Electric Vehicle Conference, March 2012
%
% Copyright 2012 The MathWorks, Inc.

%% Lookup Table Breakpoints

SOC_LUT = [0 0.1 0.25 0.5 0.75 0.9 1]';
Temperature_LUT = [-20 -15 -10 0 20 40] + 273.15;

%% Em Branch Properties (OCV, Capacity)

% Battery capacity
Capacity_LUT = [
2.741  2.903  3.333  4.059  4.180  4.178
]; %Ampere*hours

% Em open-circuit voltage vs SOC rows and T columns
Em_LUT = [
3.238  3.199  3.189  3.101  3.029  3.142
3.309  3.363  3.344  3.245  3.230  3.235
3.350  3.252  3.256  3.268  3.295  3.297
3.267  3.271  3.276  3.287  3.343  3.316
3.303  3.279  3.289  3.308  3.345  3.338
3.315  3.314  3.317  3.340  3.367  3.338
3.343  3.330  3.331  3.504  3.483  3.585
]; %Volts

%% Terminal Resistance Properties

% R0 resistance vs SOC rows and T columns
R0_LUT = [
0.0475  0.0304  0.0276  0.0148  0.0124  0.0019
0.0539  0.0450  0.0280  0.0121  0.0116  0.0023
0.0655  0.0400  0.0254  0.0171  0.0243  0.0075
0.0439  0.0276  0.0256  0.0116  0.0062  0.0038
0.0537  0.0389  0.0252  0.0116  0.0214  0.0055
0.0471  0.0443  0.0245  0.0123  0.0389  0.0010
0.0425  0.0270  0.0182  0.0130  0.0095  0.0211
]; %Ohms

%% RC Branch 1 Properties

% R1 Resistance vs SOC rows and T columns
R1_LUT = [
0.1124  0.0893  0.0963  0.0762  0.0686  0.0103
0.0792  0.0851  0.0727  0.0386  0.0346  0.0030
0.7022  0.0420  0.0543  0.0217  0.0737  0.0987
0.0025  0.0136  0.0170  0.0249  0.1033  0.2771
0.0254  0.0189  0.0086  0.0068  0.0325  0.0025
0.0283  0.0230  0.0265  0.0137  0.0225  0.0033
0.0523  0.0510  0.0298  0.0427  0.0497  0.0291
]; %Ohms

% C1 Capacitance vs SOC rows and T columns
C1_LUT = [
619     493     873    1941     860   22842
351     221      19    1115    2072   74025
10435    2209    3895    5088    6814  298857
25987   24765   40020   71649   89099  665892
4779    1001    4522    4008    5591   53143
663      15      45    1128    1935    6313
148      10      12     512     541     108

% R2 Resistance vs SOC rows and T columns
R2_LUT = [
0.0941  0.0137  0.0432  0.3822  0.3938  0.4072
0.0966  0.1342  0.0773  0.0591  0.0930  0.1976
0.0569  0.0275  0.0303  0.0061  0.0293  0.0067
0.0475  0.0483  0.0284  0.0143  0.0405  0.0027
0.0193  0.0144  0.0160  0.0071  0.0132  0.0056
0.0386  0.0354  0.0397  0.0348  0.1296  0.0052
0.2546  0.3326  0.6113  0.9565  0.9837  0.9115
]; %Ohms

% C2 Capacitance vs SOC rows and T columns
C2_LUT = [
14      78      21     115   27539   13861
44695  212996  143644  361717  346974  362745
1268     414     216    3876    3623   75454
208     103     222     847     886   39630
36     163     492    1921    5320   58952
3156   14964   29348   68274   68279  256576
16210   99517  242065  140296  140437  331497

%% Thermal Properties

% Cell dimensions and sizes
cell_thickness = 0.0084; %m
cell_width = 0.215; %m
cell_height = 0.220; %m

% Cell surface area
cell_area = 2 * (...
cell_thickness * cell_width +...
cell_thickness * cell_height +...
cell_width * cell_height); %m^2

% Cell volume
cell_volume = cell_thickness * cell_width * cell_height; %m^3

% Cell mass
cell_mass = 1; %kg

% Volumetric heat capacity
% assumes uniform heat capacity throughout the cell
% ref: J. Electrochemical Society 158 (8) A955-A969 (2011) pA962
cell_rho_Cp = 2.04E6; %J/m3/K

% Specific Heat
cell_Cp_heat = cell_rho_Cp * cell_volume; %J/kg/K

% Convective heat transfer coefficient
% For natural convection this number should be in the range of 5 to 25
h_conv = 5; %W/m^2/K

%% Initial Conditions

% Charge deficit
Qe_init = 0.8; %Ampere*hours

% Ambient Temperature
T_init = 20 + 273.15; %K

```