I am new to the OpenModelica, but i am seeing great opportunity to use these tools.
So, anybody is interested to work in thermal simulations of Li-ion....
Please discuss how we should start ........
First we will discuss at what level we should try out the thermal simulation
As per me,
First Phase - Collecting small amounts of  Li-ion cell datas of different chemistries available in Openliterature using that data, we can generate some Dynamic response of Voltage and IR 
Second Phase - Simulating Heat generation from the Li-ion cells
Third Phase - Adding cooling elements around the cell to see What type of cooling is required

This may take years but let us collaborate and build these type of models .....learn together