Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 51 | Integrated Robotics Battery/BMS |
Adi Nikumbh Rishav Kumar Ritvik Kumar |
Shengyan Liu | proposal1.pdf |
|
| ## Robotics Low Voltage BMS/Battery Pack Team Members: rishavk2 ritvik3 nikumbh2 ## Problem One issue with the development of robotics systems for small companies is the issue of battery packs. Manufacturing of a battery pack can be dangerous, and can require the expensive development of a custom BMS system. There are currently few options for completely developed and integrated lightweight battery packs that also contain a high quality BMS system that has capabilities of cutting voltage off in the event of issues. We propose a solution that uses a combination of temperature sensors and voltage sensors to develop a BMS system that can detect when our battery is in danger of thermal runaway and take action to prevent it. This system will be lightweight and inexpensive, making it suitable for use in a wide range of drones, robots and other applications. With the rapidly increasing use of drones and autonomous robots in a wide range of applications, from agriculture to logistics, the need for reliable and safe battery systems is more important than ever. Our solution will help to ensure that these systems are safe and reliable, reducing the risk of development and making robotics safer for everyone. ## Solution Our solution will be a prototype of a battery pack containing a battery management system (BMS). The system will use temperature sensors to monitor the temperature of the battery, and voltage sensors to monitor the voltage of the battery. These sensors will be hosted on a PCB daughterboard that will directly interface with each cell. The daughterboard will be connected to a mainboard that will be responsible for processing the data from the sensors and taking action to fault the BMS if an improper condition is detected. The fault conditions will include overvoltage, undervoltage, overcurrent, and over temperature or under temperature. If any of these conditions are detected, the BMS will take action to prevent thermal runaway, such as shutting down the battery output through a contactor, or initiating the cooling of our pack through fans. We plan to create a 50V max, 44.4V nominal, 12s1p system that can be used in a wide range of applications, from drones to robotics. Solution Components ## Battery Pack This subsystem will be a 12s1p lithium ion battery pack. We will use high capacity pouch cells with a nominal voltage of 3.7V. We have chosen pouch cells due to being able to manufacture our pack without needing to spot weld. The cells will be connected in series to create a 44.4V nominal battery pack, with a capacity of 13 ah. The voltage was chosen to match the 52V system the Tesla Optimus robot runs off of. The battery pack will be housed in a lightweight and durable enclosure, with provisions for mounting the BMS and other components. The cells will be bolted together with low resistance bolts, and the pack will be designed to be easily disassembled for maintenance and repair. The pack will also include provisions for cooling, such as vents or heat sinks, to help prevent thermal runaway. ## Daughterboard This subsystem will be a PCB that will host the temperature and voltage sensors. The daughterboard will be connected to the mainboard via a two wire isoSPI interface, which will allow for easy communication between the two boards. The daughterboard will be responsible for monitoring the temperature and voltage of each cell in the battery pack, and sending this data to the mainboard for processing. The daughterboard will use Analog Devices LTC chips to monitor the voltage of each cell, and will use thermistors to monitor the temperature of each cell. The daughterboard will also include provisions for connecting to the mainboard, such as headers or connectors. ## Mainboard The mainboard will be a PCB that will host the microcontroller and other components. The mainboard will be responsible for processing the data from the daughterboard, and taking action to fault the BMS if an improper condition is detected. The mainboard will use a STM32H7 microcontroller to process the data from the daughterboard, and will use relays or MOSFETs to control the battery output. The mainboard will also include provisions for connecting to the daughterboard, such as headers or connectors. ## Software The software for the BMS will be developed using the STM32 HAL library, and will be responsible for processing the data from the daughterboard and taking action to fault the BMS if an improper condition is detected. The software will use a state machine to monitor the temperature and voltage of each cell, and will take action to prevent thermal runaway if any of the fault conditions are detected. The software will also include provisions for logging data, such as temperature and voltage readings, to help with debugging and troubleshooting. It will communicate with a ground station via a serial interface, such as UART or CAN, to provide real-time data and status updates. ## Criterion For Success In order to successfully complete this project, we will need to meet the following criteria: - The BMS must be able to monitor the temperature and voltage of each cell in the battery pack, and take action if any of the fault conditions are detected. This action could include cooling the battery pack, shutting down the battery output, or other actions as necessary. - The BMS must be able to communicate with a ground station via a serial interface, such as UART or CAN, to provide real-time data and status updates. - The BMS must be lightweight and inexpensive, making it suitable for use in a wide range of applications. We also have a number of extensions that we would like to pursue if we have time. Our project will still be - deemed successful without them, but these would allow us to showcase additional technical complexity - Integration of a shunt resistor or hall effect sensor to measure current and pack power onboard - Development of a passive or active cell balancing algorithm - The development of a laptop hosted GUI to view the live status of the cells inside the pack - Wireless transmission of the pack data for viewing - (very stretch) integration of an onboard DCDC to output variable voltage and power |
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