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Modeling the supercapacitor: Error Failed to find consistent initial values. Last time step is not converged.

GaneshM Battery Modelling

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Hai,
I have been trying to simulate the model of supercapacitor. Based on the li_battery model from model library , I gave all inputs required for my model to simulate. I hope I gave all my boundary conditions. While solving this model I am consistently getting the error.

Failed to find consistent initial values.
Last time step is not converged.

I have no clue how to proceed and I have tried few suggestions from this forum , those include solving stationary, changing solver. While changing solver to PARDISO, I was ending up with this error

Failed to find consistent initial values.
The_relative_error_is_greater_than_the_relative_tolerance
Relative_residual: 3e-08, Relative_error: 3.6e+02
Last time step is not converged.

my model contains following, {all derivatives are partial}

in electrode phase

d/dx(-sigma*d/dx(phi1))= -[S_d*C_d*d/dt(phi1-phi2)+S_f*jf]
BC
i_1=-sigma*d/dx(phi1)=Icell at 1
i_1 = 0 at 2
phi1= V_0= 0.5 V at t=0
faradaic reaction in subdomain expression
jf = i_0[exp(alpha_a*eta*F/(R*T))-exp(-alpha_c*eta*F/(R*T))]

in electrolyte phase
d/dx(-kp*d/dx(phi2)-kp*RT*K_junc*1/c2*d/dx(c2)/F) = S_d*C_d*d/dt(phi1-phi2)+S_f*jf

BC
i_2=-kp*d/dx(phi2)-kp*RT*K_junc*1/c2*d/dx(c2)/F = 0 at 1
i_2= I_cell at 2
phi2= -V_0= -0.5V

concentration of electrolyte gradient
d/dt(c2) = d/dt(D_s*d/dx(c2))+[S_d*C_d/(2*F*epsilon)*d/dt(phi1-phi2)+S_f*jf/(2*F*epsilon)](1-t_p0)

c2 = C_S0 at t =0
insulation at 1
flux at 2


d/dt(theta)= S_f*jf/(Qfox-Qfre)
theta = 1 at t =0



If someone could shed some light on this I would greatly appreciate it.
Here, I am attaching my model file in version 3.5a.
If you need any additional information, kindly ask for it.

thanks in advance
Ganesh. M


1 Reply Last Post 11.11.2013, 17:53 GMT-5
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Posted: 1 decade ago 11.11.2013, 17:53 GMT-5
Hi,

Did you develop the supercapacitor model in comsol?

Can you share with me with details?

because i'm also getting difficulty to model it
Hi, Did you develop the supercapacitor model in comsol? Can you share with me with details? because i'm also getting difficulty to model it

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