Is there an example with 3D geometry and how to set parameter function

[deng-cy]

Hi, I am interested in building an 3D electrode with porosity as a function of space. I do not know how to build a 3D model, so I am looking for examples. For parameter function, I saw a tutorial which sets the current as a function of time; it seems to me that the input variable, time, is somehow preset. For other parameters, how should I know what input variables are used in the function?

Any advice will be appreciated!

[valentinsulzer]

You can look at this file to see what inputs are required

PyBaMM/pybamm/parameters/lithium_ion_parameters.py

Lines 464 to 466 in dad2b10

	self.epsilon_init = pybamm.FunctionParameter(
	f"{Domain} electrode porosity", {"Through-cell distance (x) [m]": x}
	)

The second argument to FunctionParameter is a dictionary of the required inputs. You have to either give a function that takes all the inputs in the correct order, or just give a constant value.

However, PyBaMM does not resolve the 3D microscale geometry. We use homogenized models instead as explained in this paper.

[deng-cy]

@tinosulzer Thanks for your reply. I am not looking for microscale geometry. I also need a homogenized model yet it is 3D. If 3D is not supported, is there a tutorial/example for 2D geometry?

[valentinsulzer]

See https://github.com/rtimms/asymptotic-pouch-cell

[deng-cy]

See https://github.com/rtimms/asymptotic-pouch-cell

Thanks! I went through the example. My understanding is that it is a 1D+1D model, the second dimension z only works at current collector. The electrode does not have species flux along z direction. Is that correct? If so, is there a real 2D geometry model?

[valentinsulzer]

There is no real 2D geometry model, but our research shows that the 1+1D model is accurate, compared to a 2D COMSOL model, due to the small aspect ratio of the cell (tall and thin). See references in the linked repository