Question about cation conservation in the entire domain.

[TangLeiPlus]

Hi everyone
I have a question about the total number of cations in a battery cell.
I tried to calculate the total number of cation in Chen2020 parameter set. I caculate it in two different ways which are
Approach 1:
positive electrode volume * positive electrode concentration + electrolyte volume * electro concentration + negative electrode volume * negative electride concentration = 0.289 mol
(the concentrations here are all initial value in the parameter set)
Approach 2:
positive electrode volume * positive electrode density / positive electrode molar mass = 0.3258 mol

0.289 mol < 0.3258 mol
where do the other 0.033mol catations go? Is there any one can help me to understand this?
Many Thanks

[RuiheLi]

I think that is probably because electrode density has some errors. From my personal experience this is a parameter that not very much important in the DFN model, at least it seldom occurs in equations.

[valentinsulzer]

You can see how the total number of moles should be calculated here

PyBaMM/pybamm/parameters/lithium_ion_parameters.py

Line 139 in 959081e

self.n_Li_init = self.n_Li_particles_init + self.n_Li_e_init

and

PyBaMM/pybamm/parameters/lithium_ion_parameters.py

Line 783 in 959081e

self.n_Li_init = eps_c_init_av * self.c_max * self.domain_param.L * main.A_cc