x_Si liion.cs_surface_addm1/cs_Si_max "Intercalation level at surface of silicon particles"
U_avg (Eeq_Si_upper(x_Si)+Eeq_Si_lower(x_Si))/2 "Average equilibrium potential"
U_offset (Eeq_Si_upper(x_Si)-Eeq_Si_lower(x_Si))/2 "Offset between upper and lower equilibrium potentials"
Eeq_Si U_avg+U_offset*S "Silicon equilibrium potential"
dx_Sidt liion.iv_addm1_per1/(F_const*epss_Si*cs_Si_max) "Silicon intercalation rate"
dSdt -K_S*abs(dx_Sidt)*(S-sign(dx_Sidt)) "Time derivative of memory variable"