What are the common faults of new energy vehicles? How to repair?

1. Fault cause
Generally, after the hardware problem is eliminated, the problem is mostly caused by software and system calibration. The general reason is that the system detects that the battery temperature exceeds the preset safety value, or the system detects an occasional fault signal, which limits some functions of the vehicle at its own discretion. 2. The solution is the same as the solution to computer crash and mobile phone jam. Restart can solve most problems. In fact, a pure electric vehicle can also be seen as a big electronic product. The power supply of all electronic systems and the main engine is provided by a small battery in the engine compartment. At this time, just use a wrench to unscrew the negative wire of the small battery and keep it disconnected for about 5 minutes, so that the vehicle on-board system is completely powered off, and then tighten the negative wire of the small battery to recover. At this time, the system of the vehicle can be regarded as "restarting" after the power is cut off, and all calibration and detection are restored to the initial value. At this time, restarting the vehicle can almost be successful.
2、 Power battery insulation fault
Possible causes: water ingress into the battery box or plug-in of the electric vehicle, liquid leakage from the battery core, high ambient humidity, insulation false alarm, and the insulation of other high-voltage components (controllers, compressors, etc.) of the vehicle can not be improved. Treatment method: if there is voltage or insulation resistance value less than the specified value, the negative circuit will be sentenced to leakage; If the voltage or insulation resistance of the negative pole to the ground is less than the specified value, the positive circuit will be sentenced to leakage. The leakage point can be calculated by dividing the leakage voltage by the single string voltage value at this time, and then analyzed and processed according to different situations.
3、 Power limit light is on
This is the common "turtle light" of car owners. The fault is that the output power of the vehicle is limited, and the vehicle can only drive at the speed limit of 40 km/h. 1. There are several reasons for this phenomenon. In addition to the non-fault reason that the power battery is about to run out and the vehicle enters the protection state, the most important is that the system detects that the vehicle has a fault in the circuit system, or the power battery temperature exceeds the safe range, and the power needs to be reduced to ensure the safety of the relevant components of the vehicle. 2. Solution: If the tortoise lamp appears due to power battery power loss, it can be solved as soon as possible by finding a place to recharge; If the battery temperature is too high, it is recommended to find a place to temporarily stop and turn off the engine, and continue driving after the battery recovers to a safe temperature; If you are in a hurry and the owner can confirm that the vehicle has no other faults, you can temporarily stop the vehicle, disconnect the negative pole of the small battery in the engine compartment, restart the vehicle and "flush" the previous fault warning record. If the tortoise lamp cannot be turned off after restarting and cooling for a long time, and the power battery is confirmed to be fully charged, then it is better to contact for repair.
4、 Power battery temperature fault
1. Possible causes of excessive battery temperature difference: loose cooling fan plug, cooling fan failure. Troubleshooting: Unplug the fan plug cable; Power the fan separately and check whether the fan is normal. 2. The possible causes of high or low battery temperature: loose plug of cooling fan, failure of cooling fan, and damage of temperature probe. Troubleshooting: Unplug the fan plug cable; Power the fan separately and check whether the fan is normal; Check whether the actual temperature of the battery is too high or too low; Measure the internal resistance of temperature probe. 3. The motor produces a lot of sparks, local overheating and jitter may be caused by: the motor is burnt out due to short circuit caused by water ingress into the motor; The overload operation of the motor causes the commutator to be short-circuited and burnt out, and the phenomenon is that the commutator turns black.
5、 Abnormal noise of motor
Possible cause: the concentricity of the connection between the motor and the rear axle does not meet the standard; The brush and commutator are not well connected and need to be adjusted; The bearing on the rotor inside the motor is damaged and needs to be replaced.
6、 Power battery failure
Power battery failure (except for the failure of parts themselves, such as abnormal display and acquisition module, which does not actually occur)
Common battery faults can be viewed in MP5, such as:
① In case of battery balance fault, single voltage ultra-high or ultra-low fault, etc., the single voltage value of power battery can be checked through the instrument LCD screen to see whether there is a first-level fault: the voltage value of single or multiple batteries is greater than 3.85V or less than 2.5V; Secondary fault: voltage value of single or multiple batteries is greater than 3.75V or less than 2.7V; Level 3 fault: voltage value of single or multiple batteries is greater than 3.65V or less than 2.8V.
② If the temperature of the battery cell is too high or too low, in case of this type of fault, the highest and lowest values of the power battery cell temperature can be checked through the instrument LCD screen, and whether there is a first-level fault: the maximum temperature is greater than 75 ℃; Level II fault: the maximum temperature is greater than 70 ℃, and the minimum temperature is less than 0 ℃; Level III fault: the maximum temperature is greater than 60 ℃ and the minimum temperature is less than 5 ℃.
③ If the battery insulation level is faulty, the current insulation resistance value can be checked by using the battery information LCD screen to see if there is a first-level fault: the insulation resistance is less than 500K Ω; Secondary fault: insulation resistance is less than 300K Ω; Level III fault: insulation resistance is less than 100K Ω.
In case of type ① fault, determine which battery box a single battery is in, unpack and replace the battery. Such faults are currently handled by the after-sales personnel of the battery manufacturer;
In case of type ② fault, the temperature shall be restored to the normal range before use;
In case of type ③ fault, the insulation tester shall be used to test the insulation value of all high voltage connecting wires using the 1000V test gear. The normal insulation is above 1G Ω. In case of abnormal value, it is necessary to confirm whether the harness insulation is faulty or the high voltage consumer connected to the harness is faulty.
7、 Electrical equipment does not work
The main electrical equipment of electric vehicles include various lamps (front combined lamp, measuring lamp, reversing lamp, rear combined lamp, etc.), radio, top fan, vacuum pump, wiper, combined instrument, electric power steering gear, air conditioner, etc. During on-site commissioning, the radio, vacuum pump, combination instrument and wiper often fail to work. Abnormal operation of electrical equipment mainly refers to the inconsistency between the working state and the design state, such as the continuous pumping of vacuum pump, abnormal display of combination instrument, and great interference of radio. Fault analysis and treatment of electrical equipment not working
The operation of electrical equipment needs to meet certain conditions, and the general condition is that power supply and grounding are required. The electrical equipment does not work because there is no power supply. First, use a multimeter to determine whether there is power supply, confirm whether the harness connector is loose, and then confirm whether the grounding is normal.
If none of the above conditions exist, it may be the problem of the electrical equipment itself. You can try to connect it with another equipment of the same type. This kind of fault is usually caused by the interruption of power supply due to the harness link. The fault point can be determined by pushing forward according to the electrical schematic diagram.
8、 The whole electric vehicle has no power
1. The fuse is broken. Use a multimeter to measure the battery terminal voltage. If there is voltage output, it is normal. If there is no voltage output, the fuse is broken or the battery plug is broken or the battery is broken. 2. If the wiring plug is loose, check the power switch connector. 3. If the power switch is broken, use a multimeter to measure the voltage at both ends of the input and output lines of the power switch. If there is normal voltage output, the power switch is normal, if there is no voltage output. If the power switch is broken [when the battery has voltage output], repair or replace it.
9、 Charger does not charge
1. The charger fuse is burnt out. At this time, all indicator lights of the charger are not on, and the fuse must be replaced. 2. If the battery pack cable drops, connect the battery cable. 3. The charger plug and battery socket are not in place and should be reconnected. 4. The charger is broken. At this time, the charger fuse is normal. Use a multimeter to measure that the output voltage of the charger should be zero. In this case, first disconnect the power supply, stop using the charger, and then reuse the charger after more than ten minutes.
10、 Motor does not run
1. The fuse is burnt out and replaced. 2. The power switch is broken. Replace the power switch. Judgment method: turn on the power switch and measure the resistance between the input end and output end of the power switch with the ohm gear of a multimeter. If the resistance value is zero, it is normal. If the resistance value is infinite, the power switch is broken. 3. If the accelerator is broken, measure the voltage at the output end of the accelerator with the DC voltage range of the multimeter. If there is voltage output, it is normal; if there is no voltage output, it is abnormal; if there is voltage output, the accelerator is broken, and it must be replaced. 4. The controller is broken, and the electric control must be replaced. Use a multimeter to measure the voltage at the electronic control output terminal. If there is output voltage, it is good, otherwise it is bad. 5. The motor is burnt out. Replace the motor. 6. The wire ends of each connecting line of the motor are loose, and the wire ends of each connecting line of the motor shall be rechecked.