Design Considerations

In order to fulfill the requirements mentioned in the Goals section, we have chosen Texas Instruments as the main supplier of our Integrated Circuits. Our team decided to choose Texas Instruments over other integrated circuit companies since components from Texas Instruments are widely used in competitions such as SAE, as their products meet the SAE Regulations for our FSAE Competition.

Our team had to choose an integrated circuit from Texas Instruments that will allow us to monitor the voltage level, temperature level, as well as providing over-current protection for our battery packs. As a result, we chose Texas Instruments' BQ76pl455A-Q1 as each Integrated Circuit will allow us to monitor and balance the voltage levels of 16 battery cells in series, monitor the temperature levels of 8 battery cells, and provide over-current protection. We will be using Altium for our schematic capture and PCB layout.

For this project, our team was required to make custom components and libraries on Altium. The custom component built on Altium for the BQ76pl455A-Q1 can be shown below, the figure on the left shows the schematic diagram of the BQ76pl455A-Q1 and the figure on right the shows the PCB counterpart.

Our team ultimately chose Lithium Ion batteries as opposed to other cell chemistries due to the fact that lithium ion cells are robust and lightweight. Lithium ion cells have a lower weight to volume ratio - providing a bigger edge compared to other cell chemistries. Our goal is for our vehicle to be as light as possible in order to keep performance standards high. Furthermore, lithium ion cells are generally less expensive than other rechargeable cell chemistries. Finally, lithium ion cells has a lower self discharge rate compared to its competition - allowing for longer storage periods for the cells. A SolidWorks model of lithium ion cells can be shown below.