COMSOL Forums: Failed to find consistent initial values on lithium ion battery simulation

Re: Failed to find consistent initial values on lithium ion battery simulation

Tue, 19 Apr 2011 14:02:37 +0000

Hi,
I am a new user.I am also having the same problem,If u resolved the problem before,please help me to get right...

My error code is

Time 3.746334577378822:
Error in residual computation.
Power_of_negative
Function: ^
Failed_to_evaluate_variable
Variable: i0, Defined_as: (((k_pos*((c1max_pos-c1s_pos)^aA_pos))*(c1s_pos^aC_pos))*(c2^aA_pos))
Failed_to_evaluate_variable
Variable: i_loc, Defined_as: ((exp((((Far*aA_pos)*eta)/(Rg*T)))-exp(((((-aC_pos)*Far)*eta)/(Rg*T))))*i0)
Failed_to_evaluate_expression
Expression: d(((-K1eff*phi1x*test(phi1x)/L_pos-i_loc*Sa_pos*L_pos*test(phi1))-(0))*(dvol),{test@1})
Last time step is not converged.

Thanks,
Rajesh

Re: Failed to find consistent initial values on lithium ion battery simulation

Wed, 02 Jun 2010 13:12:20 +0000

Hi,

I am a new user and having the same problem. If i refine my mesh the error takes longer to appear. I am not sure what this means except it is an error in convergence since my value being raised to the exponent should never be negative. I am assuming that if you put a logical statement somewhere to prevent this it should be cured.

Thanks
Alex

Re: Failed to find consistent initial values on lithium ion battery simulation

Tue, 16 Mar 2010 19:30:45 +0000

Hello,

I am experimenting similar issues.
My error message is following.

Did you solve your previous issue? If so, I could be interested how you did.

I am also a new user, an advice would be more than welcome.
Don't hesitate to contact me if you need additional informations, thanks in advance.

Yannick

Error:
Time 1935360:
Error in residual computation.
Power_of_negative
Function: ^
Failed_to_evaluate_variable
Variable: dwdH, Defined_as: ((-((c^(delta-1))*(phi*(phi*(delta*beta)))))/((1+((phi*beta)*((c^delta)-1)))^2))
Failed_to_evaluate_variable
Variable: Dts_c_di, Defined_as: dwdH
Failed_to_evaluate_expression
Expression: d(((-D_c_di*cx*test(cx))-(Dts_c_di*ct*test(c)))*(dvol),{test@1})
Last time step is not converged.

Re: Failed to find consistent initial values on lithium ion battery simulation

Sun, 28 Feb 2010 07:10:17 +0000

hello,

The error, Failed to find consistent initial values, has been dispeared by modifying boundary conditions.

But 'error in residual computation' arose. maybe I need to fit the value of parameters.

The error, Last time step is not converged, is still there.

Failed to find consistent initial values on lithium ion battery simulation

Sat, 27 Feb 2010 03:48:37 +0000

I was trying to simulate a lithium ion battery problem with COMSOL 3.2a, trying to see the same effect presented in the following reference:

Premanand Ramadass, Capacity Fade Analysis of Commercial Li-ion Batteries[D], USA: University of South Carolina, 2003.

In my modified model, when the simulation starts it reports

Error:
Time 0:
Failed to find consistent initial values.
Power_of_negative
Function: power
Failed_to_evaluate_expression
Expression: diff(((+(ep*sigma*phi1x)*test(phi1x)+(ap*kp*(c1maxp-theta*c1maxp)^alpha*(theta*c1maxp)^alpha*c2^alpha*(exp(alpha*F*eta/R/T)-exp(-alpha*F*eta/F/T)))*test(phi1)-0)*dvol),phi1_test)

Last time step is not converged.

I am a new user, don't know how to do this problem

Thanks.
Wencheng Li.