def _get_esoh_solver(self, calc_esoh):
        if (
            calc_esoh is False
            or isinstance(self._model, pybamm.lead_acid.BaseModel)
            or isinstance(self._model, pybamm.equivalent_circuit.Thevenin)
            or self._model.options["working electrode"] != "both"
        ):
            return None

        return pybamm.lithium_ion.ElectrodeSOHSolver(
            self._parameter_values, self._model.param, options=self._model.options
        )