Parallel Architecture HVIL Connection #
Each pack has an independent HVIL monitoring function. In parallel architecture, only one pack HVIL pins on the Communication Connector must be routed to HVIL pins on the HV connectors of all batteries. The remaining pack’s HVIL pins on the communication connector need to be shorted to avoid battery management system (BMS) error messages.
Parallel Architecture High Voltage Harnessing #
- Route high voltage (HV) harnesses (Positive/Negative) side-by-side, avoiding large loops.
- Use shielded HV cables, with HV harness shields bonded to vehicle chassis.
- Route low voltage (LV) harnesses away from HV harnesses.
- Position loads (e.g., Power Distribution Unit (PDU)/inverters/motor etc.) away from battery pack battery disconnect unit (BDU).
- Allow provision to add external DC link capacitance pre-charge at the load input if Hibernium® battery pre-charge is not sufficient.
- Ensure HV harness assemblies are constructed identically (equal length, cable type, resistance, connectors) to maintain system balance loading and avoid current hotspots.
- Ensure HV connector polarity is correct for parallel configuration (i.e., positive to positive and negative to negative).
Should one pack be more than 5V out of balance with another, the unbalanced pack should firstly be isolated from the multipack configuration. The unbalanced pack shall be charged/discharged until the pack open circuit voltage (OCV) is within 5 V of the other pack(s) in the parallel system.
Only balanced packs (i.e. packs with OCV within 5 V of other packs) should be switched into a parallel configuration.
Parallel Architecture BMS Communication & Power Supply #
Connect each battery Communication Connector with the vehicle control unit (VCU) controller area network (CAN) and power supply.
Parallel Architecture CAN Communication #
Each battery management system (BMS) communicates independently with the vehicle control unit (VCU) over shared controller area network (CAN) network. Use DBC (CAN database) file to decode CAN messages from each BMS node.
Each BMS has a separate ID based on the pack serial number. The table below illustrates the convention used for the pack serial number and its relevant CAN ID positions marked in red and green.
|Pack SN||VCU to BMS ID||BMS to VCU ID|
Each BMS expects CAN commands from VCU to Wake-up, Power-up, Charge, Discharge, Power-down or enter Sleep mode individually, as per its pack ID.
Observe the BMS_Mode signal on the CAN to verify the mode of an individual