General Information

HEV Battery System

P0A9D Hybrid Battery Temperature Sensor \'A\' Circuit Low - General Information

Component Inspection





General Description

** What is the High Voltage Battery System?
The High Voltage Battery System consists of the Battery Management System Control Unit (BMS-ECU), Power Relay Assembly (PRA) and a Cooling Blower.
Each function is listed below :
- High Voltage Battery: Supplies electrical energy for acceleration and receives/stores electrical energy during deceleration.
- BMS ECU: Controls the High Voltage Battery by monitoring the voltage, current and temperature.
- PRA (Power relay assembly)consists of relays which link and cut high voltage, and finally, current sensor which monitors battery current. Those are an assembly in PRA.
- A safety plug : It can cut high voltage flowing as mechanically in order to protect technicians. And, there is a safety fuse in the safety plug that protect over current.
- Cooling Blower: Maintains proper High Voltage Battery temperature.
** The battery cell function and roles :
The High Voltage battery cell is the smallest unit of the High Voltage Battery pack.
The voltage of each cell is 3.75 V. The battery pack will attain 270 V by connecting all 72 cells in a series.
The BMS ECU monitors all of the 72 high-voltage cells, 5 battery temperature sensors, an ambient temperature sensor, a current sensor which checks the main battery and an auxiliary battery temperature sensor.
** The High-voltage battery specification is shown below :
Operating Voltage : for a battery pack : 200 - 310 V (for a battery cell: 2.75 - 4.3)
Operating temperature : -30 °C (-22 °F)~55 °C (131 °F)
Storage temperature : -40 °C (-40 °F)~65 °C (149 °F)
Operating Current : During charge (-)200A~ During discharge (+)200A.
Field action when High Voltage Battery discharges






DTC Description

The BMS ECU receives 5 temperature sensor inputs from the High Voltage Battery. If Battery Temperature 'A' Sensor is detected as higher than 110 °C (230 °F) the BMS ECU sets P0A9D.

DTC Detecting Condition





Specification





Diagnostic Circuit Diagram






















Signal Waveform & Data
















Fig.1) SOC 46% of high voltage battery : Max. temperature is 84 °F, Min. temperature is 84 °F at EV mode
Fig.2) SOC 45.5% of High voltage battery : temperature sensors are showing -58 °F at EV mode After disconnecting temperature sensor
Fig.3) DTC and Current Data shows temperature : -58 °F (After disconnecting temperature sensor connector at EV mode)
Fig.4) DTC and Current Data shows temperature : Max. & Min - 261 °F (After disconnecting temperature sensor connector at EV mode)