Implement voltage cutoffs

[DavidMStraub]

This uses the new StopSimulation exception to stop the simulation when hitting over- or undervoltage.

Temporarily pins pathsim to master; will merge when next version is released.

[Copilot]

Pull request overview

Adds automatic simulation termination when PyBaMM cell voltage crosses configured over-/undervoltage cutoffs, leveraging PathSim’s new StopSimulation exception so users don’t need to wire termination logic manually.

Changes:

• Raise StopSimulation from both continuous (_CellBase.func_alg) and co-sim (_CoSimCellBase._discrete_step) cell blocks when voltage exceeds cutoffs.
• Improve co-simulation initial outputs to compute t=0 open-circuit outputs via CasADi evaluation (instead of placeholder zeros).
• Add termination-focused tests and temporarily pin pathsim to a specific Git commit that includes StopSimulation.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
src/pathsim_batt/cells/pybamm_cell.py	Introduces voltage cutoff extraction, termination via StopSimulation, and improved co-sim initial outputs.
tests/cells/test_pybamm_cell.py	Adds integration tests asserting simulations stop early at voltage cutoffs and that cutoff values match PyBaMM parameters.
pyproject.toml	Temporarily pins pathsim to a Git commit to access StopSimulation.

Comments suppressed due to low confidence (1)

src/pathsim_batt/cells/pybamm_cell.py:229

• Same as above: direct indexing into parameter_values for voltage cut-offs can raise KeyError for custom/alternate parameter sets. Please add an explicit check with a clear error message (or fallback defaults) to keep the constructor failure mode predictable for API consumers.

        self._model = model
        self._parameter_values = _prepare_parameter_values(parameter_values)
        self._v_lower = float(
            self._parameter_values["Lower voltage cut-off [V]"]
        )
        self._v_upper = float(
            self._parameter_values["Upper voltage cut-off [V]"]
        )

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/pathsim_batt/cells/pybamm_cell.py:321

• Same as above: the stop condition uses V = outputs[0], which relies on _pybamm_output_vars always having terminal voltage at index 0. To avoid fragile ordering dependencies, fetch the terminal voltage by its PyBaMM variable name or add an explicit assertion/lookup so future subclasses can’t accidentally trigger cut-offs based on the wrong output.

        V = outputs[0]
        if V <= self._v_lower:
            raise StopSimulation(f"undervoltage: V={V:.4f} V <= {self._v_lower} V")
        if V >= self._v_upper:
            raise StopSimulation(f"overvoltage: V={V:.4f} V >= {self._v_upper} V")

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[DavidMStraub]

Ready to merge once new PathSim version is released.

Fixes #11.