| Page Properties |
|---|
| Target release | |
|---|
| Epic | |
|---|
| Document status | |
|---|
| Document owner | |
|---|
| Designer | |
|---|
| Developers | |
|---|
| QA | |
|---|
|
Goals
Pack
- Design a matched battery pack that consists of balanced Li-ion cells
- Design a battery pack and enclosure that provides adequate cooling for the Li-ion cells
- Determine how the pack will be mounted to the car to minimize or dampen vibrations
...
The Battery Management System (BMS) is responsible for monitoring the state our Li-ion pack, ensuring that the battery is operating within its Safe Operating Area, calculating secondary data, reporting that data, and balancing it. It consists of Analog Front-End chips that allow the board to grab pack data, and then take appropriate actions.
Assumptions
Requirements
| # | Title | User Story | Importance | Notes |
|---|
| 1 | Matched battery pack | Build a pack with balanced cells | Must Have | |
| 2 | Cooling | Designing a battery layout and enclosure that accounts for cooling requirements | Must Have | |
...
Selected Parts
Questions
Below is a list of questions to be addressed as a result of this requirements document:
| Question | Outcome |
|---|
| Are we going to run the pack at a higher voltage? Can we even run the pack at a higher voltage? | Yes. The goal will be to reach a maximum 160V. |
| Do we want to allow extra voltage to be released to balance the pack? If so, how are we going to accomplish this? |
|
| Are we still planning on using 18650 cells? | Yes |
| Are we still going to use the Panasonic NCR 18650? |
|
| How are we going to mount the pack in a way that provides shock-absorption? |
|
| What will the dimensions of the battery-box be? |
|
Not Doing
- Cell-balancing: MSXI had rudimentary cell balancing based on the voltage of a single battery string, which attempted to normalize all the cell voltages. After consideration, any effort we dedicate to doing cell balancing is better placed in building a matched pack (since the pack is replaced every race).