General Information

HEV Battery System
P1B25 High Voltage Path Fault - General Information

Component Location





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 3.75V. The battery pack will attain 270V 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 - 310V (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 sets P1B25 when there is a High Voltage supply failure. Ignition ON, the BMS ECU detects failure to charge to the MCU Capacitor. The DTC may be set due to: The Main Switch, which is installed in the High Voltage Battery, is in the "off state", the Bus Bar, which connects the battery cell in series, is open or the 125A/DC450V capacity fuse, which is part of the Safety Plug, is melted.

DTC Detecting Condition





Specification





Diagnostic Circuit Diagram






















Signal Waveform & Data




















Fig.1) SOC 45.% of high voltage battery - During KEY ON status, BMS Main Relay ON Status : YES
Fig.2) SOC 46.% of high voltage battery - During EV Mode status, the voltage of battery pack and Invert capacitor
Fig.3) SOC 46.% of high voltage battery - During EV dring mode, the voltage of battery pack and Invert capacitor
Fig.4) SOC 45.5.% of high voltage battery - During EV acelerating mode, the voltage of battery pack and Invert capacitor
Fig.5) After Key off and then Key on, the high voltage relay sequence operating waveform