#
# Base battery model class
#
import pybamm
import numbers
[docs]class BatteryModelOptions(pybamm.FuzzyDict):
"""
Attributes
----------
options: dict
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. Must be one of "true" or
"false". "false" is the default, since calculating the 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" or "irreversible".
* "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.
* "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": :class:`pybamm.sei.NoSEI` (no SEI growth)
- "constant": :class:`pybamm.sei.Constant` (constant SEI thickness)
- "reaction limited", "solvent-diffusion limited",\
"electron-migration limited", "interstitial-diffusion limited", \
or "ec reaction limited": :class:`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
- "none": no additional resistance\
.. math::
\\eta_r = \\frac{F}{RT} * (\\phi_s - \\phi_e - U)
- "distributed": properly included additional resistance term\
.. math::
\\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\
.. math::
\\eta_r = \\frac{F}{RT}
* (\\phi_s - \\phi_e - U - R_{sei} * L_{sei} * \\frac{I}{aL})
* "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.
**Extends:** :class:`dict`
"""
def __init__(self, extra_options):
self.possible_options = {
"calculate discharge energy": ["false", "true"],
"cell geometry": ["arbitrary", "pouch"],
"calculate heat source for isothermal models": ["false", "true"],
"convection": ["none", "uniform transverse", "full transverse"],
"current collector": [
"uniform",
"potential pair",
"potential pair quite conductive",
],
"dimensionality": [0, 1, 2],
"electrolyte conductivity": [
"default",
"full",
"leading order",
"composite",
"integrated",
],
"hydrolysis": ["false", "true"],
"intercalation kinetics": [
"symmetric Butler-Volmer",
"asymmetric Butler-Volmer",
"linear",
"Marcus",
"Marcus-Hush-Chidsey",
],
"interface utilisation": ["full", "constant", "current-driven"],
"lithium plating": ["none", "reversible", "irreversible"],
"lithium plating porosity change": ["false", "true"],
"loss of active material": [
"none",
"stress-driven",
"reaction-driven",
"stress and reaction-driven",
],
"operating mode": [
"current",
"voltage",
"power",
"differential power",
"explicit power",
"resistance",
"differential resistance",
"explicit resistance",
"CCCV",
],
"particle": [
"Fickian diffusion",
"fast diffusion",
"uniform profile",
"quadratic profile",
"quartic profile",
],
"particle mechanics": ["none", "swelling only", "swelling and cracking"],
"particle shape": ["spherical", "no particles"],
"particle size": ["single", "distribution"],
"SEI": [
"none",
"constant",
"reaction limited",
"solvent-diffusion limited",
"electron-migration limited",
"interstitial-diffusion limited",
"ec reaction limited",
],
"SEI film resistance": ["none", "distributed", "average"],
"SEI porosity change": ["false", "true"],
"stress-induced diffusion": ["false", "true"],
"surface form": ["false", "differential", "algebraic"],
"thermal": ["isothermal", "lumped", "x-lumped", "x-full"],
"total interfacial current density as a state": ["false", "true"],
"working electrode": ["both", "negative", "positive"],
}
default_options = {
name: options[0] for name, options in self.possible_options.items()
}
default_options["external submodels"] = []
default_options["timescale"] = "default"
# Change the default for cell geometry based on which thermal option is provided
extra_options = extra_options or {}
# return "none" if option not given
thermal_option = extra_options.get("thermal", "none")
if thermal_option in ["none", "isothermal", "lumped"]:
default_options["cell geometry"] = "arbitrary"
else:
default_options["cell geometry"] = "pouch"
# The "cell geometry" option will still be overridden by extra_options if
# provided
# Change the default for SEI film resistance based on which SEI option is
# provided
# return "none" if option not given
sei_option = extra_options.get("SEI", "none")
if sei_option == "none":
default_options["SEI film resistance"] = "none"
else:
default_options["SEI film resistance"] = "distributed"
# The "SEI film resistance" option will still be overridden by extra_options if
# provided
# Change the default for particle mechanics based on which LAM option is
# provided
# return "none" if option not given
lam_option = extra_options.get("loss of active material", "none")
if "stress-driven" in lam_option or "stress and reaction-driven" in lam_option:
default_options["particle mechanics"] = "swelling only"
else:
default_options["particle mechanics"] = "none"
# The "particle mechanics" option will still be overridden by extra_options if
# provided
# Change the default for stress-induced diffusion based on which particle
# mechanics option is provided. If the user doesn't supply a particle mechanics
# option set the default stress-induced diffusion option based on the default
# particle mechanics option which may change depending on other options
# (e.g. for stress-driven LAM the default mechanics option is "swelling only")
mechanics_option = extra_options.get("particle mechanics", "none")
if (
mechanics_option == "none"
and default_options["particle mechanics"] == "none"
):
default_options["stress-induced diffusion"] = "false"
else:
default_options["stress-induced diffusion"] = "true"
# The "stress-induced diffusion" option will still be overridden by
# extra_options if provided
options = pybamm.FuzzyDict(default_options)
# any extra options overwrite the default options
for name, opt in extra_options.items():
if name in default_options:
options[name] = opt
else:
if name == "particle cracking":
raise pybamm.OptionError(
"The 'particle cracking' option has been renamed. "
"Use 'particle mechanics' instead."
)
else:
raise pybamm.OptionError(
"Option '{}' not recognised. Best matches are {}".format(
name, options.get_best_matches(name)
)
)
# If "SEI film resistance" is "distributed" then "total interfacial current
# density as a state" must be "true"
if options["SEI film resistance"] == "distributed":
options["total interfacial current density as a state"] = "true"
# Check that extra_options did not try to provide a clashing option
if (
extra_options.get("total interfacial current density as a state")
== "false"
):
raise pybamm.OptionError(
"If 'sei film resistance' is 'distributed' then 'total interfacial "
"current density as a state' must be 'true'"
)
# Options not yet compatible with particle-size distributions
if options["particle size"] == "distribution":
if options["lithium plating"] != "none":
raise NotImplementedError(
"Lithium plating submodels do not yet support particle-size "
"distributions."
)
if options["particle"] in ["quadratic profile", "quartic profile"]:
raise NotImplementedError(
"'quadratic' and 'quartic' concentration profiles have not yet "
"been implemented for particle-size ditributions"
)
if options["particle mechanics"] != "none":
raise NotImplementedError(
"Particle mechanics submodels do not yet support particle-size"
" distributions."
)
if options["particle shape"] != "spherical":
raise NotImplementedError(
"Particle shape must be 'spherical' for particle-size distribution"
" submodels."
)
if options["SEI"] != "none":
raise NotImplementedError(
"SEI submodels do not yet support particle-size distributions."
)
if options["stress-induced diffusion"] == "true":
raise NotImplementedError(
"stress-induced diffusion cannot yet be included in "
"particle-size distributions."
)
if options["thermal"] == "x-full":
raise NotImplementedError(
"X-full thermal submodels do not yet support particle-size"
" distributions."
)
# Renamed options
if options["particle"] == "fast diffusion":
raise pybamm.OptionError(
"The 'fast diffusion' option has been renamed. "
"Use 'uniform profile' instead."
)
if options["SEI porosity change"] in [True, False]:
raise pybamm.OptionError(
"SEI porosity change must now be given in string format "
"('true' or 'false')"
)
# Some standard checks to make sure options are compatible
if options["dimensionality"] == 0:
if options["current collector"] not in ["uniform"]:
raise pybamm.OptionError(
"current collector model must be uniform in 0D model"
)
if options["convection"] == "full transverse":
raise pybamm.OptionError(
"cannot have transverse convection in 0D model"
)
if (
options["thermal"] in ["x-lumped", "x-full"]
and options["cell geometry"] != "pouch"
):
raise pybamm.OptionError(
options["thermal"] + " model must have pouch geometry."
)
if options["thermal"] == "x-full" and options["dimensionality"] != 0:
n = options["dimensionality"]
raise pybamm.OptionError(
f"X-full thermal submodels do not yet support {n}D current collectors"
)
if isinstance(options["stress-induced diffusion"], str):
if (
options["stress-induced diffusion"] == "true"
and options["particle mechanics"] == "none"
):
raise pybamm.OptionError(
"cannot have stress-induced diffusion without a particle "
"mechanics model"
)
if options["working electrode"] != "both":
if options["thermal"] == "x-full":
raise pybamm.OptionError(
"X-full thermal submodel is not compatible with half-cell models"
)
elif options["thermal"] == "x-lumped" and options["dimensionality"] != 0:
n = options["dimensionality"]
raise pybamm.OptionError(
f"X-lumped thermal submodels do not yet support {n}D "
"current collectors in a half-cell configuration"
)
# Check options are valid
for option, value in options.items():
if option == "external submodels" or option == "working electrode":
pass
else:
if isinstance(value, str) or option in [
"dimensionality",
"operating mode",
"timescale",
]: # some options accept non-strings
value = (value,)
else:
if not (
(
option
in [
"intercalation kinetics",
"interface utilisation",
"loss of active material",
"particle mechanics",
"particle",
"stress-induced diffusion",
]
and isinstance(value, tuple)
and len(value) == 2
)
):
# more possible options that can take 2-tuples to be added
# as they come
raise pybamm.OptionError(
f"\n'{value}' is not recognized in option '{option}'. "
"Values must be strings or (in some cases) "
"2-tuples of strings"
)
for val in value:
if option == "timescale":
if not (val == "default" or isinstance(val, numbers.Number)):
raise pybamm.OptionError(
"'timescale' option must be either 'default' "
"or a number"
)
elif val not in self.possible_options[option]:
if not (option == "operating mode" and callable(val)):
raise pybamm.OptionError(
f"\n'{val}' is not recognized in option '{option}'. "
f"Possible values are {self.possible_options[option]}"
)
super().__init__(options.items())
[docs] def print_options(self):
"""
Print the possible options with the ones currently selected
"""
for key, value in self.items():
if key in self.possible_options.keys():
print(f"{key!r}: {value!r} (possible: {self.possible_options[key]!r})")
else:
print(f"{key!r}: {value!r}")
[docs] def print_detailed_options(self):
"""
Print the docstring for Options
"""
print(self.__doc__)
@property
def negative(self):
"Returns the options for the negative electrode"
# index 0 in a 2-tuple for the negative electrode
return BatteryModelDomainOptions(self.items(), 0)
@property
def positive(self):
"Returns the options for the positive electrode"
# index 1 in a 2-tuple for the positive electrode
return BatteryModelDomainOptions(self.items(), 1)
class BatteryModelDomainOptions(dict):
def __init__(self, dict_items, index):
super().__init__(dict_items)
self.index = index
def __getitem__(self, key):
options = super().__getitem__(key)
if isinstance(options, str):
return options
else:
# 2-tuple, first is negative domain, second is positive domain
return options[self.index]
[docs]class BaseBatteryModel(pybamm.BaseModel):
"""
Base model class with some default settings and required variables
**Extends:** :class:`pybamm.BaseModel`
"""
def __init__(self, options=None, name="Unnamed battery model"):
super().__init__(name)
self.options = options
self.submodels = {}
self._built = False
self._built_fundamental_and_external = False
@pybamm.BaseModel.timescale.setter
def timescale(self, value):
"""Set the timescale"""
raise NotImplementedError(
"Timescale cannot be directly overwritten for this model. "
"Pass a timescale to the 'timescale' option instead."
)
@pybamm.BaseModel.length_scales.setter
def length_scales(self, value):
"""Set the length scales"""
raise NotImplementedError(
"Length scales cannot be directly overwritten for this model. "
)
@property
def default_geometry(self):
return pybamm.battery_geometry(
options=self.options,
current_collector_dimension=self.options["dimensionality"],
)
@property
def default_var_pts(self):
base_var_pts = {
"x_n": 20,
"x_s": 20,
"x_p": 20,
"r_n": 20,
"r_p": 20,
"y": 10,
"z": 10,
"R_n": 30,
"R_p": 30,
}
# Reduce the default points for 2D current collectors
if self.options["dimensionality"] == 2:
base_var_pts.update({"x_n": 10, "x_s": 10, "x_p": 10})
return base_var_pts
@property
def default_submesh_types(self):
base_submeshes = {
"negative electrode": pybamm.Uniform1DSubMesh,
"separator": pybamm.Uniform1DSubMesh,
"positive electrode": pybamm.Uniform1DSubMesh,
"negative particle": pybamm.Uniform1DSubMesh,
"positive particle": pybamm.Uniform1DSubMesh,
"negative particle size": pybamm.Uniform1DSubMesh,
"positive particle size": pybamm.Uniform1DSubMesh,
}
if self.options["dimensionality"] == 0:
base_submeshes["current collector"] = pybamm.SubMesh0D
elif self.options["dimensionality"] == 1:
base_submeshes["current collector"] = pybamm.Uniform1DSubMesh
elif self.options["dimensionality"] == 2:
base_submeshes["current collector"] = pybamm.ScikitUniform2DSubMesh
return base_submeshes
@property
def default_spatial_methods(self):
base_spatial_methods = {
"macroscale": pybamm.FiniteVolume(),
"negative particle": pybamm.FiniteVolume(),
"positive particle": pybamm.FiniteVolume(),
"negative particle size": pybamm.FiniteVolume(),
"positive particle size": pybamm.FiniteVolume(),
}
if self.options["dimensionality"] == 0:
# 0D submesh - use base spatial method
base_spatial_methods[
"current collector"
] = pybamm.ZeroDimensionalSpatialMethod()
elif self.options["dimensionality"] == 1:
base_spatial_methods["current collector"] = pybamm.FiniteVolume()
elif self.options["dimensionality"] == 2:
base_spatial_methods["current collector"] = pybamm.ScikitFiniteElement()
return base_spatial_methods
@property
def options(self):
return self._options
@options.setter
def options(self, extra_options):
options = BatteryModelOptions(extra_options)
# Options that are incompatible with models
if isinstance(self, pybamm.lithium_ion.BaseModel):
if options["convection"] != "none":
raise pybamm.OptionError(
"convection not implemented for lithium-ion models"
)
if isinstance(self, pybamm.lithium_ion.SPMe):
if options["electrolyte conductivity"] not in [
"default",
"composite",
"integrated",
]:
raise pybamm.OptionError(
"electrolyte conductivity '{}' not suitable for SPMe".format(
options["electrolyte conductivity"]
)
)
if isinstance(self, pybamm.lead_acid.BaseModel):
if options["thermal"] != "isothermal" and options["dimensionality"] != 0:
raise pybamm.OptionError(
"Lead-acid models can only have thermal "
"effects if dimensionality is 0."
)
if options["SEI"] != "none" or options["SEI film resistance"] != "none":
raise pybamm.OptionError("Lead-acid models cannot have SEI formation")
if options["lithium plating"] != "none":
raise pybamm.OptionError("Lead-acid models cannot have lithium plating")
if (
isinstance(self, (pybamm.lead_acid.LOQS, pybamm.lead_acid.Composite))
and options["surface form"] == "false"
and options["hydrolysis"] == "true"
):
raise pybamm.OptionError(
"""must use surface formulation to solve {!s} with hydrolysis
""".format(
self
)
)
self._options = options
def set_standard_output_variables(self):
# Time
self.variables.update(
{
"Time": pybamm.t,
"Time [s]": pybamm.t * self.timescale,
"Time [min]": pybamm.t * self.timescale / 60,
"Time [h]": pybamm.t * self.timescale / 3600,
}
)
# Spatial
var = pybamm.standard_spatial_vars
L_x = self.param.L_x
L_z = self.param.L_z
self.variables.update(
{
"x": var.x,
"x [m]": var.x * L_x,
"x_n": var.x_n,
"x_n [m]": var.x_n * L_x,
"x_s": var.x_s,
"x_s [m]": var.x_s * L_x,
"x_p": var.x_p,
"x_p [m]": var.x_p * L_x,
}
)
if self.options["dimensionality"] == 1:
self.variables.update({"z": var.z, "z [m]": var.z * L_z})
elif self.options["dimensionality"] == 2:
# Note: both y and z are scaled with L_z
self.variables.update(
{"y": var.y, "y [m]": var.y * L_z, "z": var.z, "z [m]": var.z * L_z}
)
# Initialize "total reaction" variables
# These will get populated by the "get_coupled_variables" methods, and then used
# later by "set_rhs" or "set_algebraic", which ensures that we always have
# added all the necessary variables by the time the sum is used
self.variables.update(
{
"Sum of electrolyte reaction source terms": 0,
"Sum of positive electrode electrolyte reaction source terms": 0,
"Sum of x-averaged positive electrode "
"electrolyte reaction source terms": 0,
"Sum of interfacial current densities": 0,
"Sum of positive electrode interfacial current densities": 0,
"Sum of x-averaged positive electrode interfacial current densities": 0,
}
)
if not self.half_cell:
self.variables.update(
{
"Sum of negative electrode electrolyte reaction source terms": 0,
"Sum of x-averaged negative electrode "
"electrolyte reaction source terms": 0,
"Sum of negative electrode interfacial current densities": 0,
"Sum of x-averaged negative electrode interfacial current densities"
"": 0,
}
)
def build_fundamental_and_external(self):
# Get the fundamental variables
for submodel_name, submodel in self.submodels.items():
pybamm.logger.debug(
"Getting fundamental variables for {} submodel ({})".format(
submodel_name, self.name
)
)
self.variables.update(submodel.get_fundamental_variables())
# Set the submodels that are external
for sub in self.options["external submodels"]:
self.submodels[sub].external = True
# Set any external variables
self.external_variables = []
for submodel_name, submodel in self.submodels.items():
pybamm.logger.debug(
"Getting external variables for {} submodel ({})".format(
submodel_name, self.name
)
)
external_variables = submodel.get_external_variables()
self.external_variables += external_variables
self._built_fundamental_and_external = True
def build_coupled_variables(self):
# Note: pybamm will try to get the coupled variables for the submodels in the
# order they are set by the user. If this fails for a particular submodel,
# return to it later and try again. If setting coupled variables fails and
# there are no more submodels to try, raise an error.
submodels = list(self.submodels.keys())
count = 0
# For this part the FuzzyDict of variables is briefly converted back into a
# normal dictionary for speed with KeyErrors
self._variables = dict(self._variables)
while len(submodels) > 0:
count += 1
for submodel_name, submodel in self.submodels.items():
if submodel_name in submodels:
pybamm.logger.debug(
"Getting coupled variables for {} submodel ({})".format(
submodel_name, self.name
)
)
try:
self.variables.update(
submodel.get_coupled_variables(self.variables)
)
submodels.remove(submodel_name)
except KeyError as key:
if len(submodels) == 1 or count == 100:
# no more submodels to try
raise pybamm.ModelError(
"Missing variable for submodel '{}': {}.\n".format(
submodel_name, key
)
+ "Check the selected "
"submodels provide all of the required variables."
)
else:
# try setting coupled variables on next loop through
pybamm.logger.debug(
"Can't find {}, trying other submodels first".format(
key
)
)
# Convert variables back into FuzzyDict
self.variables = pybamm.FuzzyDict(self._variables)
def build_model_equations(self):
# Set model equations
for submodel_name, submodel in self.submodels.items():
if submodel.external is False:
pybamm.logger.verbose(
"Setting rhs for {} submodel ({})".format(submodel_name, self.name)
)
submodel.set_rhs(self.variables)
pybamm.logger.verbose(
"Setting algebraic for {} submodel ({})".format(
submodel_name, self.name
)
)
submodel.set_algebraic(self.variables)
pybamm.logger.verbose(
"Setting boundary conditions for {} submodel ({})".format(
submodel_name, self.name
)
)
submodel.set_boundary_conditions(self.variables)
pybamm.logger.verbose(
"Setting initial conditions for {} submodel ({})".format(
submodel_name, self.name
)
)
submodel.set_initial_conditions(self.variables)
submodel.set_events(self.variables)
pybamm.logger.verbose(
"Updating {} submodel ({})".format(submodel_name, self.name)
)
self.update(submodel)
self.check_no_repeated_keys()
def build_model(self):
# Check if already built
if self._built:
raise pybamm.ModelError(
"""Model already built. If you are adding a new submodel, try using
`model.update` instead."""
)
pybamm.logger.info("Start building {}".format(self.name))
if self._built_fundamental_and_external is False:
self.build_fundamental_and_external()
self.build_coupled_variables()
self.build_model_equations()
pybamm.logger.debug("Setting voltage variables ({})".format(self.name))
self.set_voltage_variables()
pybamm.logger.debug("Setting SoC variables ({})".format(self.name))
self.set_soc_variables()
pybamm.logger.debug("Setting degradation variables ({})".format(self.name))
self.set_degradation_variables()
self.set_summary_variables()
self._built = True
pybamm.logger.info("Finish building {}".format(self.name))
@property
def summary_variables(self):
return self._summary_variables
@summary_variables.setter
def summary_variables(self, value):
"""
Set summary variables
Parameters
----------
value : list of strings
Names of the summary variables. Must all be in self.variables.
"""
for var in value:
if var not in self.variables:
raise KeyError(
f"No cycling variable defined for summary variable '{var}'"
)
self._summary_variables = value
def set_summary_variables(self):
self._summary_variables = []
def get_intercalation_kinetics(self, domain):
options = getattr(self.options, domain.lower())
if options["intercalation kinetics"] == "symmetric Butler-Volmer":
return pybamm.kinetics.SymmetricButlerVolmer
elif options["intercalation kinetics"] == "asymmetric Butler-Volmer":
return pybamm.kinetics.AsymmetricButlerVolmer
elif options["intercalation kinetics"] == "linear":
return pybamm.kinetics.Linear
elif options["intercalation kinetics"] == "Marcus":
return pybamm.kinetics.Marcus
elif options["intercalation kinetics"] == "Marcus-Hush-Chidsey":
return pybamm.kinetics.MarcusHushChidsey
@property
def inverse_intercalation_kinetics(self):
if self.options["intercalation kinetics"] == "symmetric Butler-Volmer":
return pybamm.kinetics.InverseButlerVolmer
else:
raise pybamm.OptionError(
"Inverse kinetics are only implemented for symmetric Butler-Volmer. "
"Use option {'surface form': 'algebraic'} to use forward kinetics "
"instead."
)
[docs] def set_external_circuit_submodel(self):
"""
Define how the external circuit defines the boundary conditions for the model,
e.g. (not necessarily constant-) current, voltage, etc
"""
if self.options["operating mode"] == "current":
model = pybamm.external_circuit.ExplicitCurrentControl(
self.param, self.options
)
elif self.options["operating mode"] == "voltage":
model = pybamm.external_circuit.VoltageFunctionControl(
self.param, self.options
)
elif self.options["operating mode"] == "power":
model = pybamm.external_circuit.PowerFunctionControl(
self.param, self.options, "algebraic"
)
elif self.options["operating mode"] == "differential power":
model = pybamm.external_circuit.PowerFunctionControl(
self.param, self.options, "differential without max"
)
elif self.options["operating mode"] == "explicit power":
model = pybamm.external_circuit.ExplicitPowerControl(
self.param, self.options
)
elif self.options["operating mode"] == "resistance":
model = pybamm.external_circuit.ResistanceFunctionControl(
self.param, self.options, "algebraic"
)
elif self.options["operating mode"] == "differential resistance":
model = pybamm.external_circuit.ResistanceFunctionControl(
self.param, self.options, "differential without max"
)
elif self.options["operating mode"] == "explicit resistance":
model = pybamm.external_circuit.ExplicitResistanceControl(
self.param, self.options
)
elif self.options["operating mode"] == "CCCV":
model = pybamm.external_circuit.CCCVFunctionControl(
self.param, self.options
)
elif callable(self.options["operating mode"]):
model = pybamm.external_circuit.FunctionControl(
self.param, self.options["operating mode"], self.options
)
self.submodels["external circuit"] = model
def set_transport_efficiency_submodels(self):
self.submodels[
"electrolyte transport efficiency"
] = pybamm.transport_efficiency.Bruggeman(
self.param, "Electrolyte", self.options
)
self.submodels[
"electrode transport efficiency"
] = pybamm.transport_efficiency.Bruggeman(self.param, "Electrode", self.options)
def set_thermal_submodel(self):
if self.options["thermal"] == "isothermal":
thermal_submodel = pybamm.thermal.isothermal.Isothermal(
self.param, self.options
)
elif self.options["thermal"] == "lumped":
thermal_submodel = pybamm.thermal.Lumped(
self.param,
self.options,
)
elif self.options["thermal"] == "x-lumped":
if self.options["dimensionality"] == 0:
thermal_submodel = pybamm.thermal.Lumped(self.param, self.options)
elif self.options["dimensionality"] == 1:
thermal_submodel = pybamm.thermal.pouch_cell.CurrentCollector1D(
self.param,
self.options,
)
elif self.options["dimensionality"] == 2:
thermal_submodel = pybamm.thermal.pouch_cell.CurrentCollector2D(
self.param,
self.options,
)
elif self.options["thermal"] == "x-full":
if self.options["dimensionality"] == 0:
thermal_submodel = pybamm.thermal.OneDimensionalX(
self.param, self.options
)
self.submodels["thermal"] = thermal_submodel
def set_current_collector_submodel(self):
if self.options["current collector"] in ["uniform"]:
submodel = pybamm.current_collector.Uniform(self.param)
elif self.options["current collector"] == "potential pair":
if self.options["dimensionality"] == 1:
submodel = pybamm.current_collector.PotentialPair1plus1D(self.param)
elif self.options["dimensionality"] == 2:
submodel = pybamm.current_collector.PotentialPair2plus1D(self.param)
self.submodels["current collector"] = submodel
def set_interface_utilisation_submodel(self):
if self.half_cell:
domains = ["Counter", "Positive"]
else:
domains = ["Negative", "Positive"]
for domain in domains:
name = domain.lower() + " interface utilisation"
if domain == "Counter":
domain = "Negative"
util = getattr(self.options, domain.lower())["interface utilisation"]
if util == "full":
self.submodels[name] = pybamm.interface_utilisation.Full(
self.param, domain, self.options
)
elif util == "constant":
self.submodels[name] = pybamm.interface_utilisation.Constant(
self.param, domain, self.options
)
elif util == "current-driven":
if self.half_cell and domain == "Negative":
reaction_loc = "interface"
elif self.x_average:
reaction_loc = "x-average"
else:
reaction_loc = "full electrode"
self.submodels[name] = pybamm.interface_utilisation.CurrentDriven(
self.param, domain, self.options, reaction_loc
)
def set_voltage_variables(self):
ocp_n = self.variables["Negative electrode open circuit potential"]
ocp_p = self.variables["Positive electrode open circuit potential"]
ocp_n_av = self.variables[
"X-averaged negative electrode open circuit potential"
]
ocp_p_av = self.variables[
"X-averaged positive electrode open circuit potential"
]
ocp_n_dim = self.variables["Negative electrode open circuit potential [V]"]
ocp_p_dim = self.variables["Positive electrode open circuit potential [V]"]
ocp_n_av_dim = self.variables[
"X-averaged negative electrode open circuit potential [V]"
]
ocp_p_av_dim = self.variables[
"X-averaged positive electrode open circuit potential [V]"
]
ocp_n_left = pybamm.boundary_value(ocp_n, "left")
ocp_n_left_dim = pybamm.boundary_value(ocp_n_dim, "left")
ocp_p_right = pybamm.boundary_value(ocp_p, "right")
ocp_p_right_dim = pybamm.boundary_value(ocp_p_dim, "right")
ocv_av = ocp_p_av - ocp_n_av
ocv_av_dim = ocp_p_av_dim - ocp_n_av_dim
ocv = ocp_p_right - ocp_n_left
ocv_dim = ocp_p_right_dim - ocp_n_left_dim
# overpotentials
if self.half_cell:
eta_r_n_av = self.variables[
"Lithium metal interface reaction overpotential"
]
eta_r_n_av_dim = self.variables[
"Lithium metal interface reaction overpotential [V]"
]
else:
eta_r_n_av = self.variables[
"X-averaged negative electrode reaction overpotential"
]
eta_r_n_av_dim = self.variables[
"X-averaged negative electrode reaction overpotential [V]"
]
eta_r_p_av = self.variables[
"X-averaged positive electrode reaction overpotential"
]
eta_r_p_av_dim = self.variables[
"X-averaged positive electrode reaction overpotential [V]"
]
delta_phi_s_n_av = self.variables["X-averaged negative electrode ohmic losses"]
delta_phi_s_n_av_dim = self.variables[
"X-averaged negative electrode ohmic losses [V]"
]
delta_phi_s_p_av = self.variables["X-averaged positive electrode ohmic losses"]
delta_phi_s_p_av_dim = self.variables[
"X-averaged positive electrode ohmic losses [V]"
]
delta_phi_s_av = delta_phi_s_p_av - delta_phi_s_n_av
delta_phi_s_av_dim = delta_phi_s_p_av_dim - delta_phi_s_n_av_dim
eta_r_av = eta_r_p_av - eta_r_n_av
eta_r_av_dim = eta_r_p_av_dim - eta_r_n_av_dim
# SEI film overpotential
if self.half_cell:
eta_sei_av = self.variables["SEI film overpotential"]
eta_sei_av_dim = self.variables["SEI film overpotential [V]"]
else:
eta_sei_av = self.variables["X-averaged SEI film overpotential"]
eta_sei_av_dim = self.variables["X-averaged SEI film overpotential [V]"]
# TODO: add current collector losses to the voltage in 3D
self.variables.update(
{
"X-averaged open circuit voltage": ocv_av,
"Measured open circuit voltage": ocv,
"X-averaged open circuit voltage [V]": ocv_av_dim,
"Measured open circuit voltage [V]": ocv_dim,
"X-averaged reaction overpotential": eta_r_av,
"X-averaged reaction overpotential [V]": eta_r_av_dim,
"X-averaged SEI film overpotential": eta_sei_av,
"X-averaged SEI film overpotential [V]": eta_sei_av_dim,
"X-averaged solid phase ohmic losses": delta_phi_s_av,
"X-averaged solid phase ohmic losses [V]": delta_phi_s_av_dim,
}
)
# Battery-wide variables
V = self.variables["Terminal voltage"]
V_dim = self.variables["Terminal voltage [V]"]
eta_e_av_dim = self.variables["X-averaged electrolyte ohmic losses [V]"]
eta_c_av_dim = self.variables["X-averaged concentration overpotential [V]"]
num_cells = pybamm.Parameter(
"Number of cells connected in series to make a battery"
)
self.variables.update(
{
"X-averaged battery open circuit voltage [V]": ocv_av_dim * num_cells,
"Measured battery open circuit voltage [V]": ocv_dim * num_cells,
"X-averaged battery reaction overpotential [V]": eta_r_av_dim
* num_cells,
"X-averaged battery solid phase ohmic losses [V]": delta_phi_s_av_dim
* num_cells,
"X-averaged battery electrolyte ohmic losses [V]": eta_e_av_dim
* num_cells,
"X-averaged battery concentration overpotential [V]": eta_c_av_dim
* num_cells,
"Battery voltage [V]": V_dim * num_cells,
}
)
# Variables for calculating the equivalent circuit model (ECM) resistance
# Need to compare OCV to initial value to capture this as an overpotential
ocv_init = self.param.ocv_init
ocv_init_dim = self.param.ocv_ref + self.param.potential_scale * ocv_init
eta_ocv = ocv - ocv_init
eta_ocv_dim = ocv_dim - ocv_init_dim
# Current collector current density for working out euiqvalent resistance
# based on Ohm's Law
i_cc = self.variables["Current collector current density"]
i_cc_dim = self.variables["Current collector current density [A.m-2]"]
# ECM overvoltage is OCV minus terminal voltage
v_ecm = ocv - V
v_ecm_dim = ocv_dim - V_dim
# Current collector area for turning resistivity into resistance
A_cc = self.param.A_cc
# Hack to avoid division by zero if i_cc is exactly zero
# If i_cc is zero, i_cc_not_zero becomes 1. But multiplying by sign(i_cc) makes
# the local resistance 'zero' (really, it's not defined when i_cc is zero)
def x_not_zero(x):
return ((x > 0) + (x < 0)) * x + (x >= 0) * (x <= 0)
i_cc_not_zero = x_not_zero(i_cc)
i_cc_dim_not_zero = x_not_zero(i_cc_dim)
self.variables.update(
{
"Change in measured open circuit voltage": eta_ocv,
"Change in measured open circuit voltage [V]": eta_ocv_dim,
"Local ECM resistance": pybamm.sign(i_cc)
* v_ecm
/ (i_cc_not_zero * A_cc),
"Local ECM resistance [Ohm]": pybamm.sign(i_cc)
* v_ecm_dim
/ (i_cc_dim_not_zero * A_cc),
}
)
# Cut-off voltage
self.events.append(
pybamm.Event(
"Minimum voltage",
V - self.param.voltage_low_cut,
pybamm.EventType.TERMINATION,
)
)
self.events.append(
pybamm.Event(
"Maximum voltage",
V - self.param.voltage_high_cut,
pybamm.EventType.TERMINATION,
)
)
# Cut-off open-circuit voltage (for event switch with casadi 'fast with events'
# mode)
# A tolerance of ~1 is sufficiently small since the dimensionless voltage is
# scaled with the thermal voltage (0.025V) and hence has a range of around 60
tol = 5
self.events.append(
pybamm.Event(
"Minimum voltage switch",
V - (self.param.voltage_low_cut - tol),
pybamm.EventType.SWITCH,
)
)
self.events.append(
pybamm.Event(
"Maximum voltage switch",
V - (self.param.voltage_high_cut + tol),
pybamm.EventType.SWITCH,
)
)
# Power and resistance
I_dim = self.variables["Current [A]"]
I_dim_not_zero = x_not_zero(I_dim)
self.variables.update(
{
"Terminal power [W]": I_dim * V_dim,
"Power [W]": I_dim * V_dim,
"Resistance [Ohm]": pybamm.sign(I_dim) * V_dim / I_dim_not_zero,
}
)
[docs] def set_degradation_variables(self):
"""
Set variables that quantify degradation.
This function is overriden by the base battery models
"""
pass
[docs] def set_soc_variables(self):
"""
Set variables relating to the state of charge.
This function is overriden by the base battery models
"""
pass
[docs] def process_parameters_and_discretise(self, symbol, parameter_values, disc):
"""
Process parameters and discretise a symbol using supplied parameter values
and discretisation. Note: care should be taken if using spatial operators
on dimensional symbols. Operators in pybamm are written in non-dimensional
form, so may need to be scaled by the appropriate length scale. It is
recommended to use this method on non-dimensional symbols.
Parameters
----------
symbol : :class:`pybamm.Symbol`
Symbol to be processed
parameter_values : :class:`pybamm.ParameterValues`
The parameter values to use during processing
disc : :class:`pybamm.Discretisation`
The discrisation to use
Returns
-------
:class:`pybamm.Symbol`
Processed symbol
"""
# Set y slices
if disc.y_slices == {}:
variables = list(self.rhs.keys()) + list(self.algebraic.keys())
disc.set_variable_slices(variables)
# Set boundary conditions (also requires setting parameter values)
if disc.bcs == {}:
self.boundary_conditions = parameter_values.process_boundary_conditions(
self
)
disc.bcs = disc.process_boundary_conditions(self)
# Process
param_symbol = parameter_values.process_symbol(symbol)
disc_symbol = disc.process_symbol(param_symbol)
return disc_symbol