Kia Soul EV Owner's Manual Quiz
Electric Vehicle Battery System

Description and Operation

In this manual: Electric Vehicle Battery System
General Information — 17Maintenance — 17Drive Shaft and Axle — 15Suspension System — 36Steering — 24Restraints — 48Brake System — 37Body (Interior and Exterior) — 207Body Electrical System — 203Heating, Ventilation, and Air Conditioning — 80Electric Vehicle Battery System — 115
~2min read

Description

High Voltage Battery Management System

The High Voltage Battery Management System consists of the BMS ECU and PRA. It controls SOC (State of Charge), output, diagnosis and troubleshooting, cell balancing, cooling, power supply and shutdown. The Power Relay Assembly (PRA) consists of the main relay, precharge relay, precharge resistor, battery current sensor and battery heater relay. It is connected to the high voltage battery through the bus bar. [Main Function]
Purpose
SOC Control
  • Calculation of SOC by measuring voltage/current/temperature
Battery Output Control
  • Battery protection, prediction of available power, prevention of overcharge/overdischarge by calculating input/output power as system status
PRA Control
  • Shut off high voltage system power when the ignition is turned on/off.
  • Prevention of accidents due to high voltage system failure
Cooling Control
  • Maintain battery temperature by controlling the cooling fan.
Troubleshooting
(Refer to "Troubleshooting")
  • System troubleshooting, data monitoring and software control
  • Limit output fail-safe
  • Prevent accidents by controlling relays

  • SOC (State Of Charge): available energy in the battery
  • SOC = [Discharge Current] / [Battery Rated Capacity] × 100%

High Voltage Battery Heater System

If the temperature is too low, the battery may freeze, which may result in reduced output voltage. Therefore, to prevent this, a heating system is applied to the high voltage battery. It is automatically controlled based on temperature. The heater relay is controlled by the BMS ECU, and when the heater relay is turned on, high voltage is supplied to each heater. Even when the ignition is off, the VCU regularly commands the BMS ECU to prevent the battery from freezing. If the temperature reaches the normal range, the BMS ECU waits for the VCU to command battery heater operation via CAN communication.
If the battery SOC is too low during heater operation, the BMS ECU stops heater operation. If the battery charge level is too low, the heating system will not operate even at low temperature.

Operation

High Voltage Battery Management System

1. Measure cell voltage, temperature, current and resistance. 2. Transmit BMS control data to the VCU or control the drive unit.

High Voltage Battery Heater System

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