Solid Electrolyte Interphase (SEI)

For the SEI, we use the model described in the paper Microstructure-resolved degradation simulation of lithium-ion batteries in space applications from Bolay et al.

The model consider the electron diffusion and migration in the SEI layer given by the flux

• : Electron diffusion coefficient

• : Electron concentration

• : SEI length

• : Electron conductivity in SEI

When the electron reaches the SEI interface, it reacts with the electrolyte to create more SEI. This process is modeled by the differential equation

where

• : Mean partial volume of SEI

The SEI layer induces an additional potential drop given by

where

• : Conductivity for Lithium ion in SEI

• : Lithium ion current density