Working with cell parameters

In Breathe Model the parameters of the model are abstracted out and stored as encrypted json file found in the BM_Parameters directory inside your Breathe Model installation:

\Breathe_Model_Subpackages\BM_Parameters

This separation of the parameters from the model improves workflow efficiency, since you do not need to swap the model block for different cells, instead it can be referenced via the number associated with the file known as the Breathe Model JSON Number (BMJN). E.g., for a parameter file named as BMJN_1000, you input the number 1000 in the model block to access and simulate that parameter file.

If you are a Breathe Design customer, you can also run more advanced studies on virtual cell designs, such as varying design parameters, exploring the effects of production tolerances or comparing different form factors and generate Breathe Model JSON files that can then be used in system simulations via Breathe Model.

No block swapping: When working with multiple cells, you don’t need to replace the entire model block for each variant.
Fast iteration: Simply call different parameter sets at run time.
Seamless with Design: Use Breathe Design to generate virtual cells, then analyse them in Breathe Model with the same workflow.

Parameter sets

Breathe Model reads encrypted .json parameter files that are found in the BM_Parameters directory inside your Breathe Model installation:

\Breathe_Model_Subpackages\BM_Parameters

Naming convention

All parameter files are delivered using the pattern BMJN_<bmjn>, where BMJN stands for Breathe Model JSON Number with a unique number appended to it. This applies whether the parameters were experimentally derived or generated virtually via Breathe Design.

Demo default of Molicel P45B: BMJN_1000

Metadata in parameter files

Each parameter .json includes a top‑level Meta block. It stores descriptive information that helps with traceability, UI display, setting operational limits for a simulation and applying the appropriate current and power limits. It does not override the physical parameters.

Example

"Meta": {
  "cellName": "Molicel_P45B",
  "areaCell_m2": 0.0053709674886216587,
  "massCell_kg": 0.068221675454188946,
  "nominalCap_Ah": 4.5,
  "nominalEne_Wh": 16,
  "voltMin_V": 2.5,
  "voltMax_V": 4.2,
  "cRateMin": -10,
  "cRateMax": 5,
  "pRateMin": -8,
  "pRateMax": 4,
  "ambTemperatureMin_degC": 0,
  "ambTemperatureMax_degC": 50,
  "description": [],
  "modelVersion": "PBM v2.x.x"
}

Field reference

cellName — Human‑readable cell label.
areaCell_m2 — Cell area in m².
massCell_kg — Cell mass in kg.
nominalCap_Ah — Nominal capacity in Ah.
nominalEne_Wh — Nominal energy in Wh.
voltMin_V, voltMax_V — Recommended operating voltage window in V. Used for validation.
cRateMin, cRateMax — Allowed C‑rate range for current‑controlled runs.
pRateMin, pRateMax — Allowed P‑rate range for power‑controlled runs.
ambTemperatureMin_degC, ambTemperatureMax_degC — Supported ambient temperature range in °C.
description — Optional notes or tags from Breathe Design.
modelVersion — Model version (semantic version). Used for compatibility check.

Applying parameter sets in Breathe Model simulations

You can include a parameter set without rebuilding your model. Use the graphical interface documented here: Breathe Model Block.

Typical workflow:

Place or open the Breathe Model Block in your simulation.
Select the desired BMJN_<bmjn> parameter ID. E.g., for a parameter file named as BMJN_1000, you input the number 1000 in the model block.
Run the simulation to compare behaviours across cells or tolerance variants.

Note: If you’re running sweeps, keep all parameter files in BM_Parameters and reference them by BMJN ID. This keeps models clean and reproducible.