Source code for pymatgen.apps.battery.battery_abc

# coding: utf-8
# Copyright (c) Pymatgen Development Team.
# Distributed under the terms of the MIT License.


"""
This module defines the abstract base classes for battery-related classes.
Regardless of the kind of electrode, conversion or insertion, there are many
common definitions and properties, e.g., average voltage, capacity, etc. which
can be defined in a general way. The Abc for battery classes implements some of
these common definitions to allow sharing of common logic between them.
"""

from collections.abc import Sequence
import abc

from monty.json import MSONable

from scipy.constants import N_A

__author__ = "Anubhav Jain, Shyue Ping Ong"
__copyright__ = "Copyright 2012, The Materials Project"
__version__ = "0.1"
__maintainer__ = "Shyue Ping Ong"
__email__ = "shyuep@gmail.com"
__date__ = "Feb 1, 2012"
__status__ = "Beta"


[docs]class AbstractVoltagePair: """ An Abstract Base Class for a Voltage Pair. """ __metaclass__ = abc.ABCMeta @property @abc.abstractmethod def voltage(self) -> float: """ Returns: Voltage of voltage pair. """ @property @abc.abstractmethod def mAh(self): """ Returns: Energy in mAh. """ @property @abc.abstractmethod def mass_charge(self): """ Returns: Mass of charged pair. """ @property @abc.abstractmethod def mass_discharge(self): """ Returns: Mass of discharged pair. """ @property @abc.abstractmethod def vol_charge(self): """ Returns: Vol of charged pair. """ @property @abc.abstractmethod def vol_discharge(self): """ Returns: Vol of discharged pair. """ @property @abc.abstractmethod def frac_charge(self): """ Returns: Frac of working ion in charged pair. """ @property @abc.abstractmethod def frac_discharge(self): """ Returns: Frac of working ion in discharged pair. """ @property @abc.abstractmethod def working_ion_entry(self): """ Returns: Working ion as an entry. """
[docs]class AbstractElectrode(Sequence, MSONable): """ An Abstract Base Class representing an Electrode. It is essentially a sequence of VoltagePairs. Generally, subclasses only need to implement three abstract properties: voltage_pairs, working_ion and working_ion_entry. The general concept is that all other battery properties such as capacity, etc. are derived from voltage pairs. One of the major challenges with representing battery materials is keeping track of the normalization between different entries. For example, one entry might be TiO2 with one unit cell whereas another is LiTi2O4 with two unit cells. When computing battery properties, it is needed to always use a universal reference state otherwise you have normalization errors (e.g., the energy of LiTi2O4 must be divided by two to be compared with TiO2). For properties such as volume, mass, or mAh transferred within the voltage pair, a universal convention is necessary. AbstractElectrode can query for extrinsic properties of several different AbstractVoltagePairs belonging to a single charge/discharge path and be confident that the normalization is being carried out properly throughout, even if more AbstractVoltagePairs are added later. The universal normalization is defined by the reduced structural framework of the entries, which is common along the entire charge/discharge path. For example, LiTi2O4 has a reduced structural framework of TiO2. Another example is Li9V6P16O58 which would have a reduced structural framework of V3P8O29. Note that reduced structural frameworks need not be charge-balanced or physical, e.g. V3P8O29 is not charge-balanced, they are just a tool for normalization. Example: for a LiTi2O4 -> TiO2 AbstractVoltagePair, extrinsic quantities like mAh or cell volumes are given per TiO2 formula unit. Developers implementing a new battery (other than the two general ones already implemented) need to implement a VoltagePair and an Electrode. """ __metaclass__ = abc.ABCMeta @property @abc.abstractmethod def voltage_pairs(self): """ Returns all the VoltagePairs """ return @property @abc.abstractmethod def working_ion(self): """ The working ion as an Element object """ return @property @abc.abstractmethod def working_ion_entry(self): """ The working ion as an Entry object """ return def __getitem__(self, index): return self.voltage_pairs[index] def __contains__(self, obj): return obj in self.voltage_pairs def __iter__(self): return self.voltage_pairs.__iter__() def __len__(self): return len(self.voltage_pairs) @property def max_delta_volume(self): """ Maximum volume change along insertion """ vols = [v.vol_charge for v in self.voltage_pairs] vols.extend([v.vol_discharge for v in self.voltage_pairs]) return max(vols) / min(vols) - 1 @property def num_steps(self): """ The number of distinct voltage steps in from fully charge to discharge based on the stable intermediate states """ return len(self.voltage_pairs) @property def max_voltage(self): """ Highest voltage along insertion """ return max([p.voltage for p in self.voltage_pairs]) @property def min_voltage(self): """ Lowest voltage along insertion """ return min([p.voltage for p in self.voltage_pairs]) @property def max_voltage_step(self): """ Maximum absolute difference in adjacent voltage steps """ steps = [self.voltage_pairs[i].voltage - self.voltage_pairs[i + 1].voltage for i in range(len(self.voltage_pairs) - 1)] return max(steps) if len(steps) > 0 else 0 @property def normalization_mass(self): """ Returns: Mass used for normalization. This is the mass of the discharged electrode of the last voltage pair. """ return self.voltage_pairs[-1].mass_discharge @property def normalization_volume(self): """ Returns: Mass used for normalization. This is the vol of the discharged electrode of the last voltage pair. """ return self.voltage_pairs[-1].vol_discharge
[docs] def get_average_voltage(self, min_voltage=None, max_voltage=None): """ Average voltage for path satisfying between a min and max voltage. Args: min_voltage (float): The minimum allowable voltage for a given step. max_voltage (float): The maximum allowable voltage allowable for a given step. Returns: Average voltage in V across the insertion path (a subset of the path can be chosen by the optional arguments) """ pairs_in_range = self._select_in_voltage_range(min_voltage, max_voltage) if len(pairs_in_range) == 0: return 0 total_cap_in_range = sum([p.mAh for p in pairs_in_range]) total_edens_in_range = sum([p.mAh * p.voltage for p in pairs_in_range]) return total_edens_in_range / total_cap_in_range
[docs] def get_capacity_grav(self, min_voltage=None, max_voltage=None, use_overall_normalization=True): """ Get the gravimetric capacity of the electrode. Args: min_voltage (float): The minimum allowable voltage for a given step. max_voltage (float): The maximum allowable voltage allowable for a given step. use_overall_normalization (booL): If False, normalize by the discharged state of only the voltage pairs matching the voltage criteria. if True, use default normalization of the full electrode path. Returns: Gravimetric capacity in mAh/g across the insertion path (a subset of the path can be chosen by the optional arguments). """ pairs_in_range = self._select_in_voltage_range(min_voltage, max_voltage) normalization_mass = self.normalization_mass \ if use_overall_normalization or len(pairs_in_range) == 0 \ else pairs_in_range[-1].mass_discharge return sum([pair.mAh for pair in pairs_in_range]) / normalization_mass
[docs] def get_capacity_vol(self, min_voltage=None, max_voltage=None, use_overall_normalization=True): """ Get the volumetric capacity of the electrode. Args: min_voltage (float): The minimum allowable voltage for a given step. max_voltage (float): The maximum allowable voltage allowable for a given step. use_overall_normalization (booL): If False, normalize by the discharged state of only the voltage pairs matching the voltage criteria. if True, use default normalization of the full electrode path. Returns: Volumetric capacity in mAh/cc across the insertion path (a subset of the path can be chosen by the optional arguments) """ pairs_in_range = self._select_in_voltage_range(min_voltage, max_voltage) normalization_vol = self.normalization_volume \ if use_overall_normalization or len(pairs_in_range) == 0 \ else pairs_in_range[-1].vol_discharge return sum([pair.mAh for pair in pairs_in_range]) / normalization_vol * 1e24 / N_A
[docs] def get_specific_energy(self, min_voltage=None, max_voltage=None, use_overall_normalization=True): """ Returns the specific energy of the battery in mAh/g. Args: min_voltage (float): The minimum allowable voltage for a given step. max_voltage (float): The maximum allowable voltage allowable for a given step. use_overall_normalization (booL): If False, normalize by the discharged state of only the voltage pairs matching the voltage criteria. if True, use default normalization of the full electrode path. Returns: Specific energy in Wh/kg across the insertion path (a subset of the path can be chosen by the optional arguments) """ return self.get_capacity_grav(min_voltage, max_voltage, use_overall_normalization) * self.get_average_voltage(min_voltage, max_voltage)
[docs] def get_energy_density(self, min_voltage=None, max_voltage=None, use_overall_normalization=True): """ Args: min_voltage (float): The minimum allowable voltage for a given step. max_voltage (float): The maximum allowable voltage allowable for a given step. use_overall_normalization (booL): If False, normalize by the discharged state of only the voltage pairs matching the voltage criteria. if True, use default normalization of the full electrode path. Returns: Energy density in Wh/L across the insertion path (a subset of the path can be chosen by the optional arguments). """ return self.get_capacity_vol(min_voltage, max_voltage, use_overall_normalization) * self.get_average_voltage(min_voltage, max_voltage)
def _select_in_voltage_range(self, min_voltage=None, max_voltage=None): """ Selects VoltagePairs within a certain voltage range. Args: min_voltage (float): The minimum allowable voltage for a given step. max_voltage (float): The maximum allowable voltage allowable for a given step. Returns: A list of VoltagePair objects """ min_voltage = min_voltage if min_voltage is not None \ else self.min_voltage max_voltage = max_voltage if max_voltage is not None \ else self.max_voltage return list(filter(lambda p: min_voltage <= p.voltage <= max_voltage, self.voltage_pairs))