galpynostatic.metric module

Metrics for benchmarking fast charging battery electrode materials.

galpynostatic.metric.bmxfc(greg, c_rate=4, loaded=0.8, full_output=False, **kwargs)

Metric for benchmarking an extreme fast charging of Li-ion materials.

This universal metric for Benchmarking battery electrode Materials for an eXtreme Fast Charging (BMXFC) is defined as the maximum State-of-Charge (SOC) retained when a material is charged for 15 minutes under constant current conditions [2]. The evaluation of the BMXFC is performed using the model in this package, which accounts for finite diffusion, charge transfer, particle size and the total charging rate.

Parameters:

  • greg (galpynostatic.model.GalvanostaticRegressor or dict) – An already fitted GalvanostaticRegressor model or a dict containing the following keys with float values definened: d in \(cm\) (particle size), dcoeff_ in \(cm^2/s\) (diffusion coefficient) and k0_ in \(cm/s\) (kinetic rate constant).

  • c_rate (int or float, default=4) – Galvanostatic charging rate (\(60 minutes / 15 minutes\), for example, for the default case).

  • loaded (float, default=0.8) – Criteria for considering the electrode material with fast charging capabilities.

  • full_output (bool, default=False) – If full_output is False (default case), the SOC value is returned. If it is True a dict is returned with the keys soc, criteria and greg, where the first one correspond with the SOC value, the second is a boolean with True if the electrode material is classified as a fast charging one and False if is not and greg with the galpynostatic.model.GalvanostaticRegregssor to allow further predictions and plots.

  • **kwargs – Additional keyword arguments that are passed and are documented in galpynostatic.model.GalvanostaticRegressor.

Returns:

  • soc (float) – BMXFC value.

  • res (dict, optional) – A dict present if full_output=True and described there.

References

galpynostatic.metric.fom(d, dcoeff)

Figure-of-Merit (FOM) for fast charging comparisons.

This metric was proposed by Xia et al. [3] and combines the diffusion coefficient, \(D\), and the geometric size, \(d\), to define the characteristic time of diffusion, \(\tau\).

Parameters:

  • d (float) – Geometric size in \(cm\).

  • dceoff (float) – Diffusion coefficient in \(cm^2/s\).

Returns:

The FOM characteristic diffusion time (\(\tau\)) value.

Return type:

float

References