How to solve the fault light of the power battery_Seven common faults of the power battery and their solutions

How to solve the power battery fault light on

What's the matter with the power battery fault light on? When the light is still on after the car is on or while driving, it means that the generator voltage is lower than the battery voltage, the generator is not working or the power supply line is faulty. At this time, the vehicle is running because the battery is supplying power, and you should go to the repair shop as soon as possible. Generator and charging circuit.

Like all batteries, a car's 12-volt battery will eventually die if left uncharged, so the car has a built-in charging system. Most cars have an alternator and voltage regulator to charge the battery and power the car while the engine is running. A typical alternator can output between 500-1000 watts of power when needed.

Because cars are so reliant on batteries, all cars have a battery indicator light on the dashboard to warn when the charging system fails. There is a simple circuit on the car that monitors the voltage produced by the alternator. If the voltage is low, turn on the battery indicator light. The battery indicator light illuminates to indicate a problem with the battery charging. If the battery light comes on and stays on while you are driving, the most common cause is a broken alternator belt, another possibility is a serious alternator failure.

The reason why the car can still operate normally when the battery indicator light is on is that the car can continue to use the electric energy stored in the battery until the electricity in the battery is exhausted. No part of the car will work when it's used up. When the battery light is on, the car can still be driven to the garage without damaging any parts. But you have to get to the garage before the battery runs out and the car turns off.

Seven common faults of power battery and their solutions

1. Voltage fault

1. High battery voltage: After the battery is fully charged, the voltage of a single string or several strings of the battery is obviously high, and the other cells are normal.

Causes of failure: ① Acquisition error; ② LMU equalization function is poor or ineffective; ③ The capacity of the battery cell is low, and the voltage rises rapidly during charging.

Processing method: ① The displayed value of the voltage of the monomer is higher than that of the other monomers, and the actual voltage value of the measured monomer is compared. If the actual value is lower than the displayed value and is the same as the voltage of other monomers, the LMU shall be measured according to the actual value. The single cell voltage is calibrated; if the measured value matches the displayed value, the single cell battery is manually discharged and balanced. ②Check whether the voltage sampling line is broken or not connected; ③Replace the LMU.

2. Low battery voltage: After the battery is fully charged, the voltage of one or several cells is obviously low, and the other cells are normal.

Causes of failure: ① Acquisition error; ② LMU equalization function is poor or invalid; ③ The self-discharge rate of the battery cell is large; ④ The battery cell capacity is low, and the voltage drops rapidly during discharge.

Processing method: ① The displayed value of the voltage of the monomer is lower than that of the other monomers, and the actual voltage value of the measured monomer is compared. If the actual value is higher than the displayed value and is the same as the voltage of other monomers, the LMU shall be measured according to the actual value. The single-cell voltage is calibrated; if the measured value matches the displayed value, the single-cell battery is manually charged and balanced. ②Check whether the voltage sampling line is broken or not connected; ③Replace the LMU; ④Replace the faulty battery pack.

3. Differential pressure: dynamic differential pressure/static differential pressure. When charging, the voltage of the single cell quickly reaches the fully charged cut-off voltage and jumps the gun; when the accelerator is stepped on, the voltage of the single cell drops faster than other strings; when the brake is applied, the voltage of the single cell rises faster than other strings.

Causes of failure: ①The fastening nut of the copper plate connecting the battery is loose; ②There is dirt on the connection surface; ③The self-discharge rate of the battery cell is high; Core leaks.

Treatment methods: ① Tighten the nut; ② Remove foreign matter on the connection surface; ③ Charge/discharge equalization of single-string batteries; ④ Replace the battery pack in question.

4. Voltage jump: When the vehicle is running or charging, the cell voltage jumps.

Causes of failure: ①The connection point of the voltage collection line is loose; ②The LUM failure.

Treatment method: ①Tighten the connection point; ②Replace the LMU.

2. Temperature faults

1. Thermal management failure;

①Heating failure (heating sheet); when the temperature is lower than a certain value, the heating will not turn on during charging.

Causes of failure: ①The heating relay or BMU is faulty; ②The power supply circuit of the heating plate or the relay is abnormal.

Treatment method: ①Repair or replace the heating relay or BMU; ②Check and repair the power supply circuit.

② Heat dissipation failure (fan); when the temperature is higher than a certain value, the fan does not work.

Failure reasons: ①Fan relay or BMU failure; ②The fan or relay power supply circuit is abnormal.

Treatment method: ①Repair or replace the fan relay or BMU failure; ②Check and repair the abnormal power supply circuit.

2. High temperature: one or several temperature points in the battery system are high, and the alarm threshold is reached during operation or charging.

Causes of failure: ① temperature sensor failure; ② LMU failure; ③ abnormal electrical connection, local heating; ④ fan not turned on, poor heat dissipation; ⑤ close to heat sources such as motors; ⑥ overcharging.

Processing method: ①Compare the resistance value of the measured temperature sensor with the displayed value. If the actual value is lower than the displayed value and is the same as other temperature values, calibrate the LMU temperature value based on the actual value; ②Tighten the electrical connection point , clear the foreign objects at the connection point; ③ ensure that the fan is turned on; ④ increase the insulation material to isolate the heat source; ⑤ suspend operation for heat dissipation; ⑥ stop charging immediately; ⑦ replace the LMU.

3. Low temperature: one or several temperature points in the battery system are low, and the alarm threshold is reached during operation or charging.

Causes of failure: ① temperature sensor failure; ② LMU failure; ③ local heating plate abnormality.

Processing method: ①Compare the resistance value of the measured temperature sensor with the displayed value. If the actual value is higher than the displayed value and is the same as other temperature values, then calibrate the LMU temperature value based on the actual value; ②Check and repair the heating sheet; ③ Replace the LMU.

4. Temperature difference; refer to the inspection method of high and low temperature. Differences in cell heating.

3. Charging failure

1. DC charging failure; GB/T 27930-2015 The charging cannot be started, the charging jumps the gun, and the SOC does not reset after charging.

  cause of issue:

① Battery failure (abnormal voltage, temperature, insulation, etc.)

②BMU failure (charging module or charging CAN abnormal)

③ The main negative and charging relay are abnormal

④ The resistance of CC1 to ground and the voltage of CC2 to ground are abnormal

⑤ PE abnormality

  Approach:

① Troubleshoot the battery

② Repair/replace failed parts

③ Intercept the charging message and analyze the cause of the failure.

2. AC charging failure;

  cause of issue:

①Battery failure (abnormal voltage, temperature, insulation, etc.)

②BMU failure (charging module or charging CAN abnormal)

③The main negative and charging relay are abnormal

④CC-to-ground resistance and CP-to-ground voltage are abnormal

⑤PE abnormality

  Approach:

①Removing battery failures

②Repair/replace failed parts

③Intercept the charging message and analyze the cause of the failure.

4. Insulation failure

Causes of failure: water in the battery box or plug-in, leakage of battery cells, high ambient humidity, false alarms of insulation, and other high-voltage components (controllers, compressors, etc.) of the vehicle are not insulated enough.

Treatment method: ① The positive pole is to the ground, if the voltage or the insulation resistance value is less than the specified value, the negative circuit is judged to be leaking; the negative pole is to the ground, if the voltage or the insulation resistance value is less than the specified value, the positive circuit is judged to be leaking. The leakage point can be calculated according to its leakage voltage divided by the single string voltage value at this time, and then analyzed and processed according to different situations.

5. Communication failure

LUM communication failure, BMU communication failure; the whole vehicle has one or several LMU information, or the whole vehicle has no BMS information.

Causes of failure: ①LMU/BMU failure; ②LMU/BMU power supply circuit or communication line is in poor contact/fault; ③Signal interference.

Treatment method: ①Replace the LMU/BMU; ②Check and repair the power supply circuit/communication line; ③Check the shielded inspection line to find and eliminate the interference source.

6. Abnormal SOC

1. Inaccurate; charging power ÷ nominal capacity = charging SOC The SOC is considered inaccurate.

2. No change;

Failure reasons: ① abnormal communication (data missing); ② abnormal current (Hall and its input and output circuits); ③ BMU failure; ④ other battery alarms.

Processing method: ① Ensure data integrity; ② Repair/replace failed parts; ③ Eliminate all battery alarms.

3. Rapid decline;

Causes of failure: ① abnormal communication cycle ② abnormal current (large Hall forward current, small feedback current); ③ monomer voltage is low, falling fast; ④ BMU fault; ⑤ low temperature.

Processing method: ①Update the BMU program; ②Repair/replace the failed parts;

4. Slow down;

Causes of failure: ① abnormal communication cycle ② abnormal current (small Hall forward current, large feedback current) ③ BMU fault.

Solution: ①Update the BMU program; ②Repair/replace the failed parts.

5. Jump; confirm whether the program version number is correct

7. Abnormal current

Causes of failure: ①Hall and its input and output circuit; ②Hall is installed in reverse; ③If the BMS demand voltage or current is 0 during DC charging, the charger will output according to the minimum output capacity.

Solution: ①Update the BMU program; ②Repair/replace the failed parts.