Voltage Faults

1, high battery voltage: after full power and put it still, single string or a few strings of battery voltage are obviously higher, other monomer is normal

The causes of the fault are: acquisition error; poor or ineffective LMU balance function ; low cell capacity ; the voltage rises rapidly when charging

Handling methods:

1)If the single voltage display value is higher than the rest of the monomer, measuring the actual voltage value for comparison, if the actual value displays lower, but equal to other monomer voltage, then taking the actual value as the standard to calibrate the LMU single voltage; if the measured value is consistent with the display value, making the single battery balanced discharge artificially.

2)Check whether the voltage sampling line is broken;

3)replace LMU. ;

2, Low battery voltage : after full power and put it still, single string or a few strings of battery voltage are obviously lower, other monomer is normal

The causes of the fault are: acquisition error; poor or ineffective LMU balance function ; the self-discharge rate of cell is large;  low cell capacity; the cell capacity is low and the voltage drops rapidly when discharging

Handling method:

1)If the single voltage display value is lower than the rest of the monomer, measuring the actual voltage value for comparison, if the actual value displays higher, but equal to other monomer voltage, then taking the actual value as the standard to calibrate the LMU single voltage; if the measured value is consistent with the display value, making the single battery balanced discharge artificially.

2)Check whether the voltage sampling line is broken or  virtual connection

3)Replace LMU;

4)Replace the fault battery pack

3, pressure difference: dynamic pressure / static pressure difference, monomer voltage reach up to full power when charging, forbid the voltage jump; when stepping on the accelerator, the monomer voltage drops faster than other string; when braking, the monomer voltage rises faster than other string

Faults reasons: bronze fastening nut that connecting  the battery loose; the connecting surface dirt; large cell self-discharge rate; welding mistake (resulting in low single cell capacity); certain single cell electrolyte leakage.

Handling method: 1)Fastening the nut;

2)Removing debris on the connecting surface;

3)balancing the charging and discharging of the single string battery;

4)replacing the fault battery pack

4, voltage jump: when the vehicle is running or charging, the monomer voltage jump

The cause of the failure is: the connection point of voltage acquisition line is loose; LUM fault

Handling method:

1)Fastening the connecting points;

2)replacing LMU.;

Temperature Failure

1, thermal management failure;

Heating failure (heating plate); when the temperature is lower than a certain value, heating but not start the device when  charging

Faults reason: heating device or BMU fault; heating plate or  supply circuit of heating device is abnormal

Handling method:

1)repair or replace heating device or BMU;

2)check and repair power supply circuit

Cooling Failure (fan); the fan doesn't work after the temperature is higher than a certain value

Causes of failure: fan, relay or BMU fault; fan or relay power supply circuit abnormal

Treatment method: repair or replace fan, relay or BMU fault; check whether the power supply circuit is abnormal

2, high temperature: one or more temperature points in the battery system are high, and reaching alarm threshold during operation or charging

Fault reasons: temperature sensor fault; LMU fault; the electrical connection abnormal, local heating; the fan is not turned on, bad heat dissipation; close to the motor; overcharging

Handling method: make comparison of measuring temperature sensor resistance value and the display value , if the actual value is lower than the displayed value, but equal to the temperature values, then taking actual value as the standard to calibrate the LMU temperature value; fastening electrical connection, clear debris of the connection point to; make sure the fan is open; isolate the thermal insulation materials and heat power; stop to operate, dissipate heat ;stop charging  immediately; replace LMU.

3, low temperature: one or more temperature points in the battery system are low, reaching the alarm threshold during operation or charging

Causes of failure: temperature sensor failure; LMU fault; abnormal local heating film

Handling method: making comparison of measuring temperature sensor resistance value and the display value, if the actual value is higher than displayed value, but equal to the temperature values, then taking the actual value as the standard to calibrate the LMU temperature value; the check and repair heating plate; replace LMU. ;

Charging Fault

1, DC charging failure; GB/T 27930-2015 can not charge，charging jump, SOC is not reset after charging

Failure causes:

1)Battery fault (voltage, temperature, insulation, etc.)

2)BMU malfunction (charging module or charging CAN exception)

3)Positive and negative charging device abnormal

4)CC1 resistance, CC2 voltage abnormal

5)PE abnormal

Handling method:

1)Eliminate battery fault

2)Repairing / replacing defective parts

3)Delete the charging message and analyze the cause of the failure

2 AC charging fault;

Failure causes:Battery fault (voltage, temperature, insulation, etc.);BMU malfunction (charging module or charging CAN exception);Positive and negative charging device abnormal;CC resistance, CP voltage abnormal;PE abnormal

Handling process

1)Eliminate battery fault

2)Repairing / replacing defective parts

3)Delete the charging message and analyze the cause of the trouble

Insulation Fault

Fault reason: water inflow to battery box or plug-in device , cell leakage, environmental humidity, insulation false; other high voltage components (controller, compressor, etc.) insulation incomplete

Handling process:

1)if the voltage or insulation resistance is less than the specified value, make sure the negative circuit leakage;

2)2)if the voltage or insulation resistance is less than the specified value, make sure the positive circuit leakage. According to the size of the leakage voltage divided by the single string voltage, then we can be calculated leakage point, analyse the problems according to the different situation then.

Communication Failure

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

Failure reasons: LMU/BMU fault;  poor contact of LMU/BMU power supply circuit or communication line / fault; signal interference

Processing methods: (1) replacing LMU/BMU; checking and repairing power supply circuit / communication line; checking shielding, inspecting line, searching and removing interference source