CTMS
Problem
The cell temperature monitoring system is a module with each segment that will monitor and report all the temperatures to the Orion 2 BMS. This is part of the AMS to monitor cell temperature to make sure that there aren't any issues, for example thermal runaway. In MD25, the method to monitor was NTC thermistors placed near the negative terminal on the AEGIS PCB. This method passed accumulator scrutineering, however this isn't the best way to monitor temperatures and could flag us this year.
The Enepaq module has a build in thermistors
Requirements (Rules)
The BMS must measure the temperatures of critical points of the Tractive Battery
- EV.7.5.1
Cell temperatures must be measured at the negative terminal of the respective cell
- EV.7.5.3
The temperature sensor used must be in direct contact with one of:
• The negative terminal itself
• The negative terminal busbar less than 10 mm away from the spot weld or clamping
source on the negative cell terminal- EV.7.5.4
For lithium based cells,
a. The temperature of a minimum of 20% of the cells must be monitored by the BMS
b. The monitored cells must be equally distributed inside the Tractive Battery Container(s)
The temperature of each cell should be monitored- EV.7.5.5
Multiple cells may be monitored with one temperature sensor, if EV.7.5 is met for all cells
sensed by the sensor- EV.7.5.6
Temperature sensors must have appropriate electrical isolation that meets one of the two:
• Between the sensor and cell
• In the sensing circuit
The isolation must consider GLV/TS isolation as well as common mode voltages between
sense locations.- EV.7.5.7
Design overview
Development plan
Test manually reading data from enepaq module temperature sensor
Prototype a PCB development board with a stm32G4