Project 1 Mechanical design of battery pack

Battery Capacity:

• 18 kWh = 18000Wh --- (Given)

• Cell ANR26650M1-B has specification such as 3.3V 2.5Ah = 8.25wh

• To generate a battery pack with 18kwh of power, we need to connect "91 cells in series and 24 cells in parallel". This will give us 300V and 60Ah, which in turn equates to 18000wh = 18kwh
• We have assumed the motor-rated voltage as 300V, and hence we got the total Battery pack capacity to be 60Ah. (18000/300 = 60Ah)
• We found the above values by using the formula:
• No. of cells in series = Battery Pack Voltage/Individual Cell Voltage = 300/3.3 = 90.9 = 91 cells in series.
• No. of cells in parallel = Battery Pack Capacity/Individual Cell Capacity = 60/2.5 = 24 cells in parallel.

Enclosure:

• The battery pack enclosure should be designed to protect the cells from physical damage and to provide adequate ventilation. The enclosure should also be designed to prevent the cells from overheating.

• A possible enclosure design is shown in the following drawing

Figure: battery pack enclosure drawing showing a metal box with vents on the sides and top (Attached separately)

• The enclosure is made of a metal box with vents on the sides and top. The vents allow air to circulate through the enclosure, which helps to prevent the cells from overheating.

Steps Involved in Building the Battery Pack

The following are the steps involved in building the battery pack:

• Gather the necessary materials, including the 3.3V 2.5 Ah cells, a battery management system (BMS), and an enclosure.

• Weld or solder the cells together in the desired configuration.

• Connect the BMS to the battery pack.

• Install the battery pack in the enclosure.

• Connect the battery pack to the load.

Analysis and Comments

• The battery pack shown in the drawings is a relatively simple design. However, it is important to note that building a battery pack can be dangerous if not done properly. It is important to follow all safety precautions and to use the proper tools and equipment.

Here are some additional comments on the battery pack design:

• The cells should be spaced evenly within the enclosure to allow for adequate airflow.

• The cells should be insulated from each other to prevent electrical short circuits.

• The BMS should be configured to protect the cells from overcharging, over-discharging, and overheating.

• The enclosure should be grounded to prevent electrical shocks.

Conclusion

This document has presented a detailed drawing and enclosure design for a battery pack using 3.3V 2.5 Ah cells, 91 cells in series, and 24 cells in parallel. The battery pack design is relatively simple, but it is important to follow all safety precautions when building the battery pack.