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…olume Each zone is now pybamm.lithium_ion.SPM, SPMe or DFN, built with the stack's options and renamed into the stack with pybamm.replace, in place of hand-written equations. Particle phases, open-circuit potential models including hysteresis, intercalation kinetics and every other electrochemical option now behave as they do in PyBaMM. A zone_model hook builds zones with a replaced submodel, for example a composite heat of mixing until PyBaMM's own builds on two phases. Held isothermal, the stacks match SPM, SPMe and DFN to 0.013, 0.008 and 0.005 mV (previously 0.03, 0.34 and 0.15 mV), and with a two-phase hysteretic negative electrode they match SPMe and DFN to 0.09 and 0.014 mV. Fixes found against PyBaMM's lumped model: - Zones spanned L_x, the electrodes and separator, while heat capacity and conductivity included the current collectors. An insulated stack heated 21% faster than the lumped cell. Zones now span the full unit cell and use the zone's own heat capacity, and the rise matches to 1e-5. - Conduction through the stack used lambda_eff, the in-plane mean. The interfaces now carry the unit cell's layers in series, and the outer zones carry half a zone of it in series with the face cooling. Core-to-skin no longer depends on the number of zones (it was 2% of the slab value at two zones) and is within 2% of a uniformly heated slab. The contact resistance is now in addition to this, default 0. - The parallel split solved current fractions, which are singular at zero current: a window starting from rest failed at t = 0. Each zone's current is now the unknown, so the stack starts from rest, and zones that differ exchange current at rest. New outputs: Left and Right face temperatures, Surface temperature (the outer faces' mean), Core temperature and Core-to-skin difference, each zone's Total current density and heat capacity, and the stack's heat terms in watts and Discharge capacity. The options "thermal", "dimensionality" and "cell geometry" are checked, since the stack's fields are its thermal model.
The current collector thicknesses are whole foils, as in PyBaMM's parameter sets, but each unit cell carried a whole foil of each, which counts every foil twice in a stack of double-sided electrodes. A new coating argument, "double-sided" by default, gives each unit cell half of each foil in the stack's thickness, its heat capacity and in-plane conductivity, and the series conduction through it, inside the zones and in the stack alike. "single-sided" keeps whole foils per unit cell, as PyBaMM's single-cell models assume. An insulated double-sided stack heats as PyBaMM's lumped cell given half of each foil, and a single-sided one as a lumped cell with whole foils.
Each zone is a full PyBaMM model and brought its own voltage cut-off events. Renamed into the stack, an experiment no longer replaced them with its own limits, so "Discharge at 3C until 2.8 V" stopped at the parameter set's lower cut-off, 3.105 V on Marquis2019. The stack sets the limits once, as before; the zones' copies are dropped. Tests now pin the options the zones are built with against PyBaMM's own models: two particle phases with one-state hysteresis under Butler-Volmer and Marcus-Hush-Chidsey kinetics on SPM, SPMe and DFN, the heat of mixing, a lumped thermal capacity, a lumped surface temperature option, and a zone_model that swaps a submodel.
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Description
Targets the branch of #5815, so it lands there when merged.
Each zone of
multilayer_3d_thermalbecomes PyBaMM's own SPM, SPMe or DFN, built with the stack's options and renamed into the stack withpybamm.replace, instead of hand-written equations. Model options (particle phases, hysteresis, intercalation kinetics) now take effect in every zone, and azone_modelhook builds zones with a replaced submodel. This replaces the zone equations, and with them the SPMe and DFN fixes in #5815, which the new zones no longer need.Also fixed, found against PyBaMM's lumped model:
L_xwhile heat capacity included the current collectors: an insulated stack heated 21% too fast. Zones now span the full unit cell.lambda_eff. Interfaces now carry the layers' series conduction, the outer faces half a zone of it, and core-to-skin no longer depends on the number of zones.coatingargument,"double-sided"by default, gives each unit cell half of each foil;"single-sided"keeps whole foils.New outputs: left and right face, surface, and core temperatures, each zone's current density and heat capacity, and the stack's heat terms in watts.
Held isothermal, the stacks match SPM, SPMe and DFN to 0.013, 0.008 and 0.005 mV, and with a two-phase hysteretic negative electrode they match SPMe and DFN to 0.09 and 0.014 mV. The README's Validation section lists every check, and the entry's tests cover each fix. The commit messages have the details.
Type of change
A model zoo entry; its bullet in
packages/pybamm-model-zoo/CHANGELOG.mdis updated, and nothing underpackages/pybamm/changes.Important checks