Overview
The purpose of this project is to gain a better understanding of the thermal properties of the cells in our Formula car through testing and modeling. These models will be used for optimizing our current cooling strategy and designing future accumulators. I planned on finding this by measuring the internal resistance of our cells with various temperatures.
The picture above shows the set up of the test. To maintain the temperature of the cell, I used a sous vide machine to control the temperature of a water bath which was flowed around the cell. A digital multimeter was used to ensure that the temperature of the cell was what I expected. I used the squidstat to run current through the cell at a constant rate and measured the voltage over time.
From the measurements, I was able to create the graph above. This showed that the internal resistance of the cell decreased with temperature. This meant that maintaining the cells at a higher temperature would be beneficial for current draw in the car. While there was a decrease in resistance with an increase of temperature, we cannot keep increasing the temperature since the cell would eventually fail.