Project 1

Required power= 150 kW and voltage of 120V

Nominal voltage of each cell = 3.6V, Capacity of each cell = 3500 mAh

Number of Cells in Series:

First, let's determine the number of cells required in series to achieve a nominal voltage of 120V:

Nominal voltage of each cell = 3.6V

Number of cells in series = Total voltage of battery pack / Nominal cell voltage

Number of cells in series = 120V / 3.6V = 33.33 (approx. 34 cells)

Number of Cells in Series:

Next, let's determine the number of cells required in parallel to achieve the desired capacity:

Capacity of each cell = 3500 mAh

Required total capacity of the battery pack = 150 kWh (or 150,000 Wh)

Number of cells in parallel = Required capacity / (Nominal capacity of a single cell x Number of cells in series)

Number of cells in parallel = (150000 W / 120 V) / (3.5 Ah x 34) = 14.39 (approximately 15 cells)

Therefore, the battery pack configuration would be 34 cells in series and 14 cells in parallel, resulting in a total of 476 cells.

BMS Topology for given battery pack:

• A battery management system (BMS) is an electronic system that is responsible for monitoring and controlling a battery pack's operation. In a master-slave BMS topology, the system is divided into two parts: a master module and multiple slave modules.

• In the case of a battery pack with 34 cells in series, the master module is responsible for monitoring the overall battery pack voltage, current, and temperature. The slave modules, on the other hand, are responsible for monitoring the voltage and temperature of each individual cell in the pack.
• The master module communicates with the slave modules through a communication bus, such as a CAN bus. The communication between the master and slave modules allows the BMS to monitor and control the battery pack's operation as a whole.
• The master module is typically a more powerful microcontroller or processor that can handle the complex calculations needed to manage the battery pack. It also contains the firmware that controls the BMS's operation and communicates with the vehicle's main controller.
• Each slave module monitors the voltage and temperature of a group of cells, typically 3-8 cells per module, depending on the specific BMS design. The slave modules report this information to the master module, which then uses it to determine the overall state of the battery pack.
• In addition to monitoring the cells' voltage and temperature, the BMS also controls the charging and discharging of the battery pack. The BMS uses information from the slave modules to balance the cells' charge levels, ensuring that no cell is overcharged or over-discharged, which can lead to damage or failure.

Overall, the master-slave BMS topology provides an efficient and effective way to manage large battery packs with multiple cells in series. It allows the BMS to monitor and control the battery pack's operation as a whole while still providing detailed information about each individual cell's performance.