Circuit/System Description

Voltage Monitoring 

The high voltage hybrid/EV battery contains 288 individual cells. Three cells are welded together in parallel and called a cell group. There is a total of 96 cell groups in the hybrid/EV battery assembly. These cell groups are electrically connected in series. Each individual cell group is rated at 3.65 V, for a nominal system voltage of 350 V direct current. The battery cell groups are electrically joined to form 10 distinct electrical modules and mechanically joined to form 5 serviceable module/rows.

Located within the high voltage Hybrid/Electric Vehicle Battery pack, the K16 Battery Energy Control Module monitors the temperature, current and voltage of the 96 battery cell groups. The voltage sense lines are attached to each individual cell group, and these sense lines terminate at a connector located on the end of the battery cell module. A voltage sense harness joins this connector to the K16 Battery Energy Control Module.

The K16 battery energy control module will determine when a fault condition is present. Diagnostics and system status are communicated from the K16 battery energy control module to the K114B Hybrid/EV Powertrain Control Module 2 through serial data. The K114B Hybrid/EV Powertrain Control Module 2 is the host controller for diagnostic trouble code information.

Thermal Monitoring 

The hybrid/EV battery pack has 6 hybrid/EV battery temperature sensors and 96 cell group voltage sensing circuits. Whenever the K16 Battery Energy Control Module and the K114B Hybrid/EV Powertrain Control Module 2 are awake and communicating they are monitoring for data that might indicate battery thermal runaway is occurring. If conditions are right, thermal monitoring may remain active after vehicle OFF or at the completion of plug-in charging for 10 minutes up to 12 hours. With vehicle OFF thermal monitoring, the high voltage contactors will be closed and the K1 14V power module will support the 12-volt battery.

The following will occur only if thermal runaway is detected - regardless of Vehicle ON/OFF state:

• A combination of Hybrid/EV Battery Low/High Circuit DTCs and/or Hybrid/EV Battery Temperature Sensor Circuit Low/High/Overtemperature DTCs and/or Hybrid/EV Battery Interface Control Module Communication/Processor/ Performance DTCs will be set
• The high voltage contactors will be commanded open
• The vehicle parking lights will flash and the horn will sound continuously until the 12-volt battery is depleted