Cell Balancing Outputs

Using the GUI software provided by Texas Instruments, we were able to balance 16 Lithium-ion battery cells. This can be achieved by setting up the battery's in a single row, and connecting the positive terminal of one battery to the negative terminal of the next battery, and so on. Next, we connected the 16 batteries to the circuit board, which was then connected to a laptop that is running the GUI software. A picture of the setup, GUI software, and results can be seen below.

Below is the result of simulating the 16 batteries with balancing turned on for one hour.

In the above picture, it can be seen that all 16 batteries have different voltage levels and are slowly going to approach the lowest battery cell voltage. It is not too clear from the one hour simulation whether that will occur or not.

Note: The box with the green filling indicates that the cell is being balanced.

For the next simulation, we decided to simulate the batteries balancing for 8 hours to get a better picture of what is happening. The result can be seen below.

In the above figure, after simulating for 8 hours, it shows a clear downward slope. For this simulation, we began with the balancing set to "OFF", and after a few minutes of it running, we turned on the balancing and saw that there was a voltage drop from each battery cell that occurred. Then the cells begin to decrease to the lowest battery cell voltage. Since our battery cells were not being charged or a load being applied to them, it will result in a longer simulation time to achieve balancing. Since our batteries were balanced by the method of passive balancing, it takes the cells with the highest charges and dissipates their charge to the cell with lowest voltage level. Passive balancing helps maximize the life expectancy of each battery, thus maintaining the battery packs longevity and performance.