data/Overview/batteryModuleDoc_parameterDefinition.m

%% Battery Module Parameters and Documentation 
% 
% This document details various options available for use in the Battery
% Module Simscape(TM) custom component.
% 
% Copyright 2020-2026 The MathWorks, Inc.

%% Battery Module Overview
% 
% A Battery Module is defined as a collection of a number of cells in
% series and / or parallel. A Battery (Table-based) block from the Simscape 
% Electrical library models the battery cell. You can specify the cell-to-cell
% variations by modifying the relevant parameters inside the custom
% component. Each module has six sides and you can choose from four
% different thermal options for each side.
% 
%% *Model Fidelity* 
%  
% * *Select Model Fidelity* — Modeling compexity of the Battery Module 
% component, specified as |Detailed|, |Grouped|, or |Lumped|. |Detailed| 
% model tracks each and every cell in the system. |Lumped| model tracks the 
% whole module as a single unit or as lumped. |Grouped| model tracks the 
% best and the worst cell in the module. The best and the worst cell is 
% determined based on the cell-to-cell variation specified in *Effective 
% rate of coolant heat transfer from each cell*, *Cell terminal resistance 
% R0 variation from baseline*, *Cell Ahr rating variation*, *Cell Self-
% discharge resistance variation from baseline Rleak*, or *External heat*. 
% For more information on the model fidelity, see table in the Appendix-A
% section. |Grouped| model working principle is shown in the image below.
% For more information on the |Grouped| model fidelity, see Appendix-B.
%
% <<batteryModuleDoc_groupedModel.png>>
%
% 
%% Battery *Cell Electrical* Parameters 
% 
% For the Battery Cell (Table-based) block in the Simscape Electrical
% library, you can specify these parameters:
% 
% * *Vector of temperatures, T* — Temperatures at which the cell or module 
% data for temperature-varying properties are tabulated, specified as a 
% vector. 
% 
% * *Single cell Ahr rating, baseline* — Cell capacity at the temperatures 
% defined in the *Vector of temperatures, T* parameter, specified as a 
% vector. 
% 
% * *Vector of state of charge values, SOC* — Range of values between 0 and 
% 1 at which the cell electrical parameters are defined, specified as a 
% vector.  
% 
% * *No load voltage, V0* — Cell open-circuit potential values at different 
% *Vector of state of charge values, SOC* and *Vector of temperatures, T* 
% points, specified as a matrix.
%
% * *Current directionality* — Current directionality, specified as 
% |Enabled| or |Disabled|. This parameter defines hystersis during charge
% and discharge cycles.
% 
% * *Terminal resistance, R0* — Cell ohmic resistance values at different 
% *Vector of state of charge values, SOC* and *Vector of temperatures, T* 
% points, specified as a matrix.
% 
% * *Self-discharge* — Cell self discharge option, specified as |Disabled|
% or |Enabled|. If you set this parameter to |Enabled|, you must then
% specify the value of the *Self-discharge resistance, Rleak(T)* parameter.
% The parameter, specified as resistance, defines a resistance for cell 
% leakage at all points defined in the *Vector of temperatures, T* 
% parameter.
% 
% * *Charge dynamics* — Options to select cell dynamics, specified as 
% |no dynamics|, |one time-constant dynamics|, |two time-constant dynamics|, 
% |three time-constant dynamics|, |four time-constant dynamics| or |five 
% time-constant dynamics|. 
% 
% * *Polarization resistance* — Polarization resistance values at different
% *Vector of state of charge values, SOC* and *Vector of temperatures, T* 
% points, specified as a matrix. You must specify the value of 
% *Polarization resistance* parameter based on the value of  *Charge 
% dynamics* parameter.
% 
% * *Time constant* — Time constant at different *Vector of state of charge 
% values, SOC* and *Vector of temperatures, T* points, specified as a
% matrix. You must specify the value of *Time constant* parameter based on 
% the value of  *Charge dynamics* parameter.
% 
%% Battery *Cell Capacity Fade* Parameters
% 
% If you set the *Fade characteristics* parameter of the Battery (Table-
% based) block to |Equations|, specify the parameters *Number of discharge 
% cycles, N*, *Change in no-load voltage after N discharge cycles (%)*, 
% *Change in terminal resistance after N discharge cycles (%)*, *Change in 
% ampere-hour rating after N discharge cycles (%)* and the *Change in 
% polarization resistance after N discharge cycles (%)*.
% 
%% Battery *Cell Thermal* Parameters
% 
% * *Cell thermal mass* — Thermal mass of a single cell, specified as a
% scalar.
% 
% * *Cell thermal conductivity* — Cell through-plane conductivity for |pouch| 
% and |can| cells, or the radial conductivity for |cylindrical| cells, 
% specified as a scalar.
% 
%% Battery *Module Electrical* Parameters
% 
% * *Number of series connected cells Ns* — Number of strings in series,
% specified as an integer.
%
% * *Number of parallel connected cells Np* — Number of parallel-cells in 
% a string, specified as an integer.
%
% * *Choose cell type* — Type of cell, specified as either |Pouch|, |Can|, 
% |Compact cylindrical|, or |Regular cylindrical|.
%
% <<batteryModuleDoc_cellType01.png>>
%
% <<batteryModuleDoc_cellType02.png>>
%
% * *Cell height* — Cell height, specified as a scalar.
%
% * *Cell width* — Cell width for |Pouch| and |Can| cells, specified as a
% scalar.
%
% * *Cell thickness* — Cell thickness for |Pouch| or |Can| cells, specified 
% as a scalar.
%
% * *Cell diameter* — Cell diameter for |Compact cylindrical| or |Regular 
% cylindrical|, specified as a scalar.
%
% * *Number of cylindrical cells in a straight line* — Number of cylindrical
% cells arranged in a straight line for packaging, specified as an integer.
%
% * *Accessory total resistance* — Resistance that combines all inline 
% resistance in a module, specified as a scalar. This resistance is the 
% sum of cell tab, busbar, cable and/or weld resistances, specified as a
% scalar.
%
% * *Cell balancing* — Cell balancing method, specified as either |none| or 
% |passive|. In this example, this parameter is set to |passive|. Upon
% selection of |passive| cell balancing, four parameters become visible.
% These parameters are: *Shunt resistor*, *Switch closed resistance*, 
% *Switch open conductance* and *Switch operation threshold*. Passive cell
% balancing is shown schematically in the figure below:
% 
% <<batteryModuleDoc_cellBalancing.png>>
%
%% Battery *Module Thermal* Parameters
%
% * *Select module thermal management* — Whether to activate thermal 
% management in the module, specified as either |None| or |Active|. If 
% you select *Select module thermal management* to |Active|, the option to 
% specify heat transfer on the six sides of the module is visible. If you 
% select *Select module thermal management* to |None| is selected, then *Heat 
% transfer coefficient to ambient* is visible. All sides of the module lose 
% heat at a rate defined by this heat transfer coefficient value. 
%
% The figure shows the labels of the six sides of the module. Each side of
% the module has four options for heat transfer — |Detailed thermal
% output|, |Lumped thermal port|, |Thermal lookup table|, or |Convection 
% boundary|.
%
% <<batteryModuleDoc_moduleThermal.png>>
% 
% * |Detailed thermal output| enables thermal node of each cell to be 
% connected to other thermal components and is provided through a output 
% node. This is useful when detailed thermal analysis and information for 
% every cell is required. Each cell then loses heat at a different rate. 
% You can connect a detailed fluids component to the output port of the 
% battery to help in design optimization studies (example : cell-to-cell 
% cooling variation). 
% 
% * |Lumped thermal port|, connects every cell to the same thermal node 
% externally.
%
% * |Convection Boundary| specifies a convection boundary condition
% on the module face, with its own heat transfer coefficient.
% 
% * |Thermal lookup table| method specifies the heat transfer from battery
% cells to the coolant using a lookup table method. The lookup table, for
% thermal resistance (W/K) values at multiple temperature and flowrate
% points, is defined for all the cells in the module. The range of 
% temperature and flowrate for coolant are defined in *Vector of 
% temperatures for LUT thermal model, Tc* and *Vector of coolant flow rates,
% L*, respectively. The *Effective rate of coolant heat transfer from each 
% cell* is a 3-D matrix of size [T,F,C] where, *T* is the size of *Vector 
% of temperatures for LUT thermal model, Tc*, *F* is the size of *Vector of
% coolant flow rates, L* and *C* is equal to the number of cells in the 
% module, *Ns* X *Np*. The values of the matrix are calculated using 
% |Detailed thermal output| or 3-D methods such as computational fluid 
% dynamics. The values of the matrix depend on the actual hardware design 
% of the cooling system or cold plates in the module. The 3D matrix is 
% described schematically in the figure below: 
%
% <<batteryModuleDoc_LUTbasedThermal.png>>
%
% The 3D matrix defines thermal resistance values at multiple temperature
% and flowrate points. During the simulation, the actual value is picked 
% based on *FlwR* and *FlwT*. *FlwR* and *FlwT* specify coolant flowrate 
% and inlet temperature based on the values set.
% 
% *FlwR* — Value between 0 and 1, specified as a scalar. The *FlwR* input 
% value is used to dynamically choose the right value of the flow rate 
% during the simulations. The value of the *FlwR* input defines the actual 
% flow rate in the module. In the *Vector of coolant flow rates, L* 
% parameter, *FlwR* equal to 0 means no flow, while *FlwR* equal to 1 means 
% highest flow rate value.
% 
% *FlwT* — Positive or negative value that, when summed to the ambient 
% temperature, equals the coolant inlet temperature. A value of +15 for the 
% *FlwT* input and 273.15 K at the *Amb* port makes the coolant inlet 
% temperature equal to 273.15 + 15 = 288.15K. A value of -15 for the *FlwT*
% input and 273.15 K at the *Amb* makes the coolant inlet temperature equal 
% to 273.15 - 15 = 258.15 K. 
% 
% <<batteryModuleDoc_moduleThermalExample.png>>
% 
% 
% To open the above example, run the command on MATLAB command prompt: 
% uiopen('Overview/batteryModuleDoc_example.slx',1)
% 
% 
% * *External heat* — External heat input to each cell in a module due to a
% hot component placed near the module, specified as a vector. 
%
% 
%% Battery Module *Cell-to-Cell Variation* Parameters
% 
% * *Vector of initial cell temperature* — Cell initial temperature,
% specified as a vector.
% 
% * *Vector of initial cell state of charge* — Cell initial state of
% charge, specified as a vector. 
% 
% * *Cell Ahr rating variation* — Cell-to-cell variations in cell capacity 
% at all *Vector of temperatures, T* points for each cell, specified as a 
% vector of scalar values. If you set this array to 1, all cell capacity 
% is the same. The array values for a cell are multiplied with the value 
% specified in the *Single cell Ahr rating, baseline* parameter to 
% calculate the actual capacity or the Ahr rating of the cell.
% 
% * *Cell terminal resistance R0 variation from baseline* — Cell-to-cell 
% variations in cell terminal resistance, specified as a vector of scalar
% values. If you set this array to 1, all cell terminal resistance values 
% are the same. The array values for a cell are multiplied with the value 
% specified in the *Terminal resistance, R0* parameter to calculate the 
% actual terminal resistance value for the cell.
%
% * *Cell Self-discharge resistance variation from baseline Rleak* — Cell-
% to-cell self-discharge, specified as a vector of scalar values. This
% parameter is visible if *Self-discharge* is |Enabled|. If you set this 
% array to 1, all cell self discharge values are the same. The array values 
% for a cell are multiplied with the value specified in the *Self-discharge 
% resistance, Rleak(T)* parameter to calculate the self-discharge 
% resistance value for the cell.
%
%% Appendix-A
%
% <<batteryModuleDoc_appendixA.png>>
% 
%% Appendix-B
%
% The best and the worst cell is automatically selected based on the user
% input for:
% 
% * *Effective rate of coolant heat transfer from each cell* (if the 
% |Thermal lookup table| is selected on a module side for the battery 
% thermal management),
% * *Cell terminal resistance R0 variation from baseline*,
% * *Cell Ahr rating variation*,
% * *Cell Self-discharge resistance variation from baseline Rleak* and
% * *External heat*
%
% If the module thermal management does not use the option |Thermal lookup 
% table|, the best and the worst cells cannot be selected based on the
% same. The cooling effect variation and best/worst cell cannot be found
% out or determined if |Detailed thermal output| or the |Lumped thermal 
% port| is used for module thermal management. In that case, the best and
% worst cells are decided based on:
%
% * *Cell terminal resistance R0 variation from baseline*,
% * *Cell Ahr rating variation*,
% * *Cell Self-discharge resistance variation from baseline Rleak* and
% * *External heat*
% 
% The code checks for cell-to-cell variation in the data for these
% parameters and skips the ones that have no variation present. If multiple
% parameters are defined with cell-to-cell variations, the best ad the
% worst cells are decided based on cell indices as per the parameter
% preference list above. These details are present in file 
% |getGroupedModelIndexFinal.m|.
% 
% In scenarios where multiple parameters are defined with cell-to-cell
% variations, it is important that the cell indices for the best and worst
% cells are same for all parameters, else the variation effect would be
% smoothed out in averaging and group-creation (|Grouped| model fidelity)
% for large modules. You will be able to simulate with warning messages if
% the cell indices for the best and worst cells differ for different
% parameters.
%