Battery cell

A battery consists of two electrodes and an electrolyte. Each are implemented by a model which takes its own set of input parameters. The convention for the input model class names is to write them using the model name followed by the suffix InputParams. In graph above, we can see that the battery model has submodel instances as properties. The property names are in black color while the model they belong to is in blue.

class BatteryInputParams(jsonstruct)

Input parameter class for the Battery model.

G: Computational Grid

SOC: Initial state of charge [-]

initT: Initial temperature [T]

NegativeElectrode: instance of ElectrodeInputParams

PositiveElectrode: instance of ElectrodeInputParams

Electrolyte: instance of ElectrolyteInputParams

ThermalModel: instance of ThermalComponentInputParams

Control: instance of ControlModelInputParams

couplingTerms: Coupling terms (describe the topological structure of the coupling between the components)

use_thermal: flag : true if coupled thermal simulation should be considered

use_particle_diffusion: flag : true if solid diffusion should be included (mainly for debugging)

Electrode components

An electrode consists of an active material, which contains an interface model and a solid diffusion model, and a current collector. Each of those components have a own set of input parameters.

Electrode

This model is derived from ElectronicComponentInputParams

class ElectrodeInputParams(jsonstruct)

Input parameter class for Electrode model

ActiveMaterial: Input parameter for the electrode active component (ActiveMaterialInputParams)

CurrentCollector: Input parameter for the current collector (CurrentCollectorInputParams)

couplingTerm: Coupling term specification

include_current_collectors: Set to true to include current collector

Active Material

class ActiveMaterialInputParams(jsonstruct)

Input parameter class for ActiveMaterial model

Interface: Input parameter for the interface InterfaceInputParams

SolidDiffusion: Input parameter for the solid diffusion model SolidDiffusionModelInputParams

density: Density

thermalConductivity: Intrinsic Thermal conductivity of the active component

specificHeatCapacity: Specific Heat capacity of the active component

electricalConductivity: Electrical conductivity / [S m^-1]

externalCouplingTerm: structure to describe external coupling (used in absence of current collector)

diffusionModelType: Choose between type of diffusion model (‘full’ or ‘simple’. The default is set to ‘full’)

BruggemanCoefficient: Volume fraction of the whole material (binder and so on included)

activeMaterialFraction: Volume fraction occupied only by the active material (default value is 1)

Interface

class InterfaceInputParams(jsonstruct)

Input parameter class for the interface model

G: Grid

theta0: Lithiation value at 0% SOC [-]

theta100: Lithiation value at 100% SOC [-]

cmax: Maximum concentration [mol m^-3]

k0: Reference rate constant [m^2.5 mol^-0.5 s^-1]

Eak: Activation energy [J mol^-1]

volumetricSurfaceArea: Volumetric surface area [m2 m^-3]

volumeFraction: Volume fraction of the active material

density: Density of the active material [kg m^-3]

n: number of electron transfer

OCP

Function to update OCP value, which is given as a struct with fields

type : “function”;
functionname : matlab function name (should be available in path)
argumentlist : [“cElectrode”, “T”, “cmax”]

j0

Interface.updateReactionRateCoefficient. The function is given as a struct with the fields:

type = {“function”, “constant”} % if “constant” is selected, the value of k0 is used to compute reaction rate
functionname : matlab function name (should be available in path)
argumentlist = [“cElectrodeSurface”, “cmax”]

Solid Diffusion Models

class SolidDiffusionModelInputParams(jsonstruct)

Base class for the solid diffusion models, see FullSolidDiffusionModelInputParams and SimplifiedSolidDiffusionModelInputParams

EaD: Activation energy [J mol^-1]

D0: Diffusion reference constant[ m^2 s^-1]

rp: Particle radius [m]

volumetricSurfaceArea: Volumetric surface area [m2 m^-3]

class FullSolidDiffusionModelInputParams(jsonstruct)

Full diffusion model (standard PXD)

N: Number of discretization intervals in the diffusion model [-]

np: Number of computational grid cells (typically set by parent model ActiveMaterial)

volumeFraction: Volume Fraction (typically set by parent model ActiveMaterial)

activeMaterialFraction: Active Material Fraction (typically set by parent model ActiveMaterial)

D: Function to update D value given as a struct with fields - D.type is in {‘function’, ‘constant’}. If ‘constant’ is chosen the value of D0 defined in parent class - D.functionname : matlab function name (should be available in path) - D.argumentlist = [“c”, “cmin”, “cmax”]

cmax: maximum concentration [mol/m^3] (only needed if D is a function)

theta0: Minimum lithiation, 0% SOC [-] (only needed if D is a function)

theta100: Maximum lithiation, 100% SOC [-] (only needed if D is a function)

class SimplifiedSolidDiffusionModelInputParams(jsonstruct): See simplified model presented in Comparison of approximate solution methods for the solid phase diffusion equation in a porous electrode model by Zhang, Qi and White, Ralph E ( Journal of power sources, 2007) [ZW07]

Current Collector

class CurrentCollectorInputParams(jsonstruct)

Input parameter class for the CurrentCollector model

externalCouplingTerm: coupling term specification of the current collector with external source

thermalConductivity: Thermal conductivity of current collector

specificHeatCapacity: Heat capacity of current collector

density: Density of current collector [kg m^-3]

Electrolyte components

class ElectrolyteInputParams(jsonstruct)

Input parameter class for Electrolyte model

compnames: Names of the components in the electrolyte

sp: Structure given properties of each component

Separator: Input parameter for the separator (SeparatorInputParams)

specificHeatCapacity: Specific Heat capacity of the electrolyte

Conductivity: Density [kg m^-3] (Note : only of the liquid part, the density of the separator is given there)

class SeparatorInputParams(jsonstruct)

Input parameter class for Separator model

porosity: Porosity [-]

thermalConductivity: Intrinsic Thermal conductivity of the electrolyte

specificHeatCapacity: Specific Heat capacity of the electrolyte

density: Density [kg m^-3]

Electronic Component

Base model for all component with a electrical potential and a charge conservation equation

class ElectronicComponentInputParams(jsonstruct)

Input parameter class for ElectronicComponent model

EffectiveElectricalConductivity

conductivity (effective value)

In many models, this value is not used as the conductivity depends on other parameters