Project 1
1. Battery cooling is directly proportional to the heat generated inside them, thus it is important to know where the heat comes from. Thermodynamic energy balance is used to formulate the heat generated. There are four ways of heat generation:
(I) Electrical Power
(II) Reversible Reactions
(III) Entropic Heating
(IV) The heat produced from the mixing due to the variation of the concentration
(V) Heat dissipated from the phase changes of the materials
For creating a calculator, I will just consider the heat produced from electrical power, which is given by the equation
Q = I2R
where I is the current and R is the resistance.
Refer to the Excel Sheet for Calculations. (All Values are gotten from the Web)
2. The analytical Equation is as follows:
which clearly states the importance of thermal conductivity (k), hence while simulating consideration of material property is important. The CFD flow can easily predict the change in the surface temperature of the battery. So if thermal conductivity is high, that will result in efficient cooling of the batteries which would definitely improve efficiency. Hence, using any solid material is not accurate while performing the simulation as it would result in negative results.
The interface between the cells and the aluminum extrusion is filled with TIM (Thermal Interface Material) also known as a gap pad or thermally conductive pad. TIM is a solid material (often wax or silicon-based) that aid heat conduction between the heat sink and the material that is being cooled.
4. For a smaller element size, the convergence iterations take more iterations between (1000-1300) for element size of 12mm and 8 mm. The convergence of the solution for a smaller element size took about 700-1000 iterations with higher accuracy. The image shows the Scaled Residual Plot of the 4mm element size of the mesh.
5. Smaller the element size creates more mesh elements which directly affects the accuracy of the result. The element size of 4mm results in better accuracy.
Results:
