Working Coulombic efficiency

[c-randall]

Description

This PR adds Coulombic efficiency to the model. Users must now specify ce as an input parameter. The Coulombic efficiency only affects how the soc evolves in time during charging:

ce = 1. if current >= 0. else model.ce
dsoc_dt = -ce*current / 3600. / model.capacity

Resolves #3

Type of change

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that improves speed/readability/etc.)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ nox -s linter [-- format]
• Code is free of misspellings: $ nox -s codespell [-- write]
• All tests pass: $ nox -s tests
• Badges are updated: $ nox -s badges

The optional -- format and -- write arguments (see above) attempt to correct formatting issues prior to running the linter, and spelling mistakes prior to running the spellcheck, respectively. You can also run all of the above checks using $ nox -s pre-commit instead of running them individually.

Further checks:

• The documentation builds: $ nox -s docs.
• Code is commented, particularly in hard-to-understand areas.
• Tests are added that prove fix is effective or that feature works.