Base Model

Event

# Base Battery Model¶

class pybamm.BaseBatteryModel(options=None, name='Unnamed battery model')[source]

Base model class with some default settings and required variables Extends: pybamm.BaseModel

property length_scales

Length scales of model

Set variables that quantify degradation. This function is overriden by the base battery models

set_external_circuit_submodel()[source]

Define how the external circuit defines the boundary conditions for the model, e.g. (not necessarily constant-) current, voltage, etc

set_soc_variables()[source]

Set variables relating to the state of charge. This function is overriden by the base battery models

property timescale

Timescale of model, to be used for non-dimensionalising time when solving

class pybamm.BatteryModelOptions(extra_options)[source]
options

A dictionary of options to be passed to the model. The options that can be set are listed below. Note that not all of the options are compatible with each other and with all of the models implemented in PyBaMM. Each option is optional and takes a default value if not provided. In general, the option provided must be a string, but there are some cases where a 2-tuple of strings can be provided instead to indicate a different option for the negative and positive electrodes.

• “calculate discharge energy”: str

Whether to calculate the discharge energy, throughput energy and throughput capacity in addition to discharge capacity. Must be one of “true” or “false”. “false” is the default, since calculating discharge energy can be computationally expensive for simple models like SPM.

• “cell geometry”str

Sets the geometry of the cell. Can be “pouch” (default) or “arbitrary”. The arbitrary geometry option solves a 1D electrochemical model with prescribed cell volume and cross-sectional area, and (if thermal effects are included) solves a lumped thermal model with prescribed surface area for cooling.

• “calculate heat source for isothermal models”str

Whether to calculate the heat source terms during isothermal operation. Can be “true” or “false”. If “false”, the heat source terms are set to zero. Default is “false” since this option may require additional parameters not needed by the electrochemical model.

• “convection”str

Whether to include the effects of convection in the model. Can be “none” (default), “uniform transverse” or “full transverse”. Must be “none” for lithium-ion models.

• “current collector”str

Sets the current collector model to use. Can be “uniform” (default), “potential pair” or “potential pair quite conductive”.

• “dimensionality”int

Sets the dimension of the current collector problem. Can be 0 (default), 1 or 2.

• “electrolyte conductivity”str

Can be “default” (default), “full”, “leading order”, “composite” or “integrated”.

• “external submodels”list

A list of the submodels that you would like to supply an external variable for instead of solving in PyBaMM. The entries of the lists are strings that correspond to the submodel names in the keys of self.submodels.

• “hydrolysis”str

Whether to include hydrolysis in the model. Only implemented for lead-acid models. Can be “false” (default) or “true”. If “true”, then “surface form” cannot be ‘false’.

• “intercalation kinetics”str

Model for intercalation kinetics. Can be “symmetric Butler-Volmer” (default), “asymmetric Butler-Volmer”, “linear”, “Marcus”, or “Marcus-Hush-Chidsey” (which uses the asymptotic form from Zeng 2014). A 2-tuple can be provided for different behaviour in negative and positive electrodes.

• “interface utilisation”: str

Can be “full” (default), “constant”, or “current-driven”.

• “lithium plating”str

Sets the model for lithium plating. Can be “none” (default), “reversible”, “partially reversible”, or “irreversible”.

• “lithium plating porosity change”str

Whether to include porosity change due to lithium plating, can be “false” (default) or “true”.

• “loss of active material”str

Sets the model for loss of active material. Can be “none” (default), “stress-driven”, “reaction-driven”, or “stress and reaction-driven”. A 2-tuple can be provided for different behaviour in negative and positive electrodes.

• “particle phases”: str

Number of phases present in the electrode. A 2-tuple can be provided for different behaviour in negative and positive electrodes. For example, set to (“2”, “1”) for a negative electrode with 2 phases, e.g. graphite and silicon.

• “operating mode”str

Sets the operating mode for the model. This determines how the current is set. Can be:

• “current” (default) : the current is explicity supplied

• “voltage”/”power”/”resistance” : solve an algebraic equation for current such that voltage/power/resistance is correct

• “differential power”/”differential resistance” : solve a differential equation for the power or resistance

• “explicit power”/”explicit resistance” : current is defined in terms of the voltage such that power/resistance is correct

• “CCCV”: a special implementation of the common constant-current constant-voltage charging protocol, via an ODE for the current

• callable : if a callable is given as this option, the function defines the residual of an algebraic equation. The applied current will be solved for such that the algebraic constraint is satisfied.

• “particle”str

Sets the submodel to use to describe behaviour within the particle. Can be “Fickian diffusion” (default), “uniform profile”, “quadratic profile”, or “quartic profile”.

• “particle shape”str

Sets the model shape of the electrode particles. This is used to calculate the surface area to volume ratio. Can be “spherical” (default), or “no particles”.

• “particle size”str

Sets the model to include a single active particle size or a distribution of sizes at any macroscale location. Can be “single” (default) or “distribution”. Option applies to both electrodes.

• “particle mechanics”str

Sets the model to account for mechanical effects such as particle swelling and cracking. Can be “none” (default), “swelling only”, or “swelling and cracking”. A 2-tuple can be provided for different behaviour in negative and positive electrodes.

• “SEI”str

Set the SEI submodel to be used. Options are:

• “none”: pybamm.sei.NoSEI (no SEI growth)

• “constant”: pybamm.sei.Constant (constant SEI thickness)

• “reaction limited”, “reaction limited (asymmetric)”, “solvent-diffusion limited”, “electron-migration limited”, “interstitial-diffusion limited”, “ec reaction limited” or “ec reaction limited (asymmetric)”: pybamm.sei.SEIGrowth

• “SEI film resistance”str

Set the submodel for additional term in the overpotential due to SEI. The default value is “none” if the “SEI” option is “none”, and “distributed” otherwise. This is because the “distributed” model is more complex than the model with no additional resistance, which adds unnecessary complexity if there is no SEI in the first place

$\eta_r = \frac{F}{RT} * (\phi_s - \phi_e - U)$
• “distributed”: properly included additional resistance term
$\eta_r = \frac{F}{RT} * (\phi_s - \phi_e - U - R_{sei} * L_{sei} * j)$
• “average”: constant additional resistance term (approximation to the true model). This model can give similar results to the “distributed” case without needing to make j an algebraic state
$\eta_r = \frac{F}{RT} * (\phi_s - \phi_e - U - R_{sei} * L_{sei} * \frac{I}{aL})$
• “SEI on cracks”str

Whether to include SEI growth on particle cracks, can be “false” (default) or “true”.

• “SEI porosity change”str

Whether to include porosity change due to SEI formation, can be “false” (default) or “true”.

• “stress-induced diffusion”str

Whether to include stress-induced diffusion, can be “false” or “true”. The default is “false” if “particle mechanics” is “none” and “true” otherwise. A 2-tuple can be provided for different behaviour in negative and positive electrodes.

• “surface form”str

Whether to use the surface formulation of the problem. Can be “false” (default), “differential” or “algebraic”.

• “thermal”str

Sets the thermal model to use. Can be “isothermal” (default), “lumped”, “x-lumped”, or “x-full”.

• “timescale”str or number

Sets the timescale of the model. If “default”, the discharge timescale, as defined by other parameters, is used. Otherwise, the number is used.

• “total interfacial current density as a state”str

Whether to make a state for the total interfacial current density and solve an algebraic equation for it. Default is “false”, unless “SEI film resistance” is distributed in which case it is automatically set to “true”.

• “working electrode”: str

Which electrode(s) intercalates and which is counter. If “both” (default), the model is a standard battery. Otherwise can be “negative” or “positive” to indicate a half-cell model.

• “x-average side reactions”: str

Whether to average the side reactions (SEI growth, lithium plating and the respective porosity change) over the x-axis in Single Particle Models, can be “false” or “true”. Default is “false” for SPMe and “true” for SPM.

Type:

dict

\*\*Extends
Type:
property negative

Returns the options for the negative electrode

property positive

Returns the options for the positive electrode

print_detailed_options()[source]

Print the docstring for Options

print_options()[source]

Print the possible options with the ones currently selected