# Dimensionless form of the DFN model II

**URL:** <https://pybamm.discourse.group/t/dimensionless-form-of-the-dfn-model-ii/487>\
**Category:** Models\
**Created:** [8 October 2026 08:55 UTC](https://pybamm.discourse.group/t/dimensionless-form-of-the-dfn-model-ii/487 "2026-10-08T08:55:34Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![isaac\_basil](https://avatars.discourse-cdn.com/v4/letter/i/96bed5/32.png) [@isaac\_basil](https://pybamm.discourse.group/u/isaac_basil)\
**Post date:** [8 October 2026 08:55 UTC](https://pybamm.discourse.group/t/dimensionless-form-of-the-dfn-model-ii/487/1 "2026-10-08T08:55:34Z")

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Hi,

There’s a previous[thread](https://pybamm.discourse.group/t/dimensionless-form-of-the-dfn-model/90) on the dimensionless form of the DFN. It says that the dimensionless form is no longer used. However, in the fickian\_diffusion.py file (which I believe is the default submodel for the DFN) the radius parameter is called R\_broad\_nondim, making me think this a dimensionless radius?

Does the DFN formulation in PyBaMM still contain some dimensionless parameters then?

Cheers,

Isaac