Diagnosis and Removal of Several Common Faults of Tesla Pure Electric Vehicle

Abstract: Pure electric vehicle is a kind of mechatronic equipment with complex technology, and its failure causes are generally complex, which brings many difficulties to fault diagnosis and elimination. This paper mainly describes the possible causes, fault analysis and solutions of several typical faults of Tesla pure electric vehicles.
Key words: Tesla; Failure; diagnosis; exclude
1、 Low range under full power
1) Possible causes of failure
(1) Battery loss is serious.
(2) Battery power estimation error.
(3) The ambient temperature is too low.
2) Fault analysis of corresponding causes
(1) The ambient temperature is the main factor affecting the discharge capacity of the battery, and too low temperature will seriously limit the discharge capacity of the battery.
(2) The power management system of pure electric vehicles calculates the range of the vehicle under the current state according to the total energy stored in the current battery and the energy required per unit mileage. If the battery management system estimates the battery power in the current state incorrectly, the system will not be able to calculate the correct range.
(3) The discharge capacity of lithium-ion batteries is related to the degree of loss. In the process of increasing the number of cycles of charging and discharging, the chemical reaction raw materials inside the lithium batteries are constantly lost. When the loss is relatively serious, the discharge capacity of the batteries is reduced, resulting in low mileage at full charge.
3) Corresponding causes and solutions
(1) If the ambient temperature is too low, the vehicle can be powered up in a static state. After the temperature sensor of the vehicle senses the low temperature, it will start the PTC heating function to heat the battery, or it can drive normally for a period of time. During the driving process, the battery temperature will also rise slowly. When the battery temperature is normal, the mileage will return to normal. If the ambient temperature is normal, go to step (2).
(2) Restart the vehicle, make the vehicle management system detect the battery again, and observe whether the display reading is normal again. If it is still abnormal, check whether the battery management system works normally; On the contrary, go to step (3).
(3) Check the loss of the battery pack. If the battery pack is seriously damaged, the battery pack should be replaced.
2、 Unable to charge
1) Possible causes of failure
(1) The charging interface is loose.
(2) The charging gun is faulty.
(3) Electric control system fault.
2) Fault analysis
(1) The loose charging interface causes the charger to have poor contact and cannot be charged.
(2) After connecting the charging interface, Tesla's charger first communicates with the battery management system, and then charges after obtaining the charging parameters. If the charger fails, it will not be able to generate communication, so it cannot be charged.
(3) Similar to point (2), if the electric control system fails, it is unable to communicate with the charger, or it is unable to obtain the battery power parameters, then the normal charging operation cannot be completed.
3) Solution
(1) Check the charging interface and reinforce it if it is loose; Otherwise, go to step (2).
(2) In the charging state, observe the charging state display of the charging gun, and then detect the charging gun. If there is any fault, repair or replace it. If there is no fault, enter step (3).
(3) Check whether the working state of the electronic control system is normal, such as whether the communication can be completed or the battery power parameters can be obtained correctly. If the function is abnormal, it needs to be repaired or replaced.
3、 Battery overheating
1) Possible causes of failure
(1) The vehicle speed continues too fast.
(2) The battery pack has internal failure.
(3) Cooling system failure.
2) Fault analysis
(1) In order to make the vehicle have a high speed, it is necessary to discharge the battery pack with a large current, and the excessive current will generate a lot of heat. If the vehicle speed remains too fast, the current will continue to be too large, resulting in too much heat to be discharged in time, causing the battery to overheat.
(2) The heat generated by the battery can not be discharged by the cooling system in time, which is the phenomenon that the battery overheats.
(3) If the battery inside the battery pack has problems, such as short circuit and other dangerous situations, the battery will also overheat.
3) Solution
(1) Reduce the speed properly. If the problem still cannot be solved, turn to step (2).
(2) It can be judged whether the cooling system is normal by measuring the temperature of the cooling system. If the temperature of the cooling system is lower than the temperature that the vehicle should have when it is running, it means that the cooling system is abnormal and should be repaired as soon as possible. If the temperature of the cooling system is normal, turn to step (3).
(3) It can detect the temperature of the battery pack. If the temperature of the battery pack exceeds the safety limit, it indicates that there is a safety problem inside the battery pack, and the battery pack should be repaired or replaced in time. This situation is dangerous. The battery pack itself generates a large amount of heat that cannot be discharged, and it is often difficult to detect because it occurs inside the battery pack. But don't worry too much. Tesla's monitoring system will give an alarm in time for this situation. There is also a thermal insulation wall between the battery pack and the cockpit. These measures have increased the escape time for passengers and ensured their safety as much as possible.
4、 Sudden acceleration of the vehicle
1) Possible causes of failure
(1) The vehicle controller is abnormal.
(2) The motor controller is abnormal.
(3) Driver operation error.
2) Fault analysis
(1) The motor controller controls the motor according to the instructions sent by the vehicle controller, while the vehicle controller sends control instructions to the motor controller through comprehensive analysis of the information of the vehicle's subordinate controllers. If the vehicle controller is abnormal, it may cause the vehicle to accelerate suddenly.
(2) The motor controller controls the motor according to the control command sent by the vehicle controller. If the motor controller is abnormal and causes the inverter to suddenly generate three-phase AC with large amplitude and high frequency, it may lead to sudden rapid acceleration of the vehicle.
3) Solution
(1) Check whether the input signal and output signal of the whole vehicle controller are normal. If the input signal is abnormal, it may be the fault of the next level controller. Find out according to the corresponding signal. If the output control signal is abnormal, it may be the fault of the whole vehicle controller. Repair or replace it in time. If the output control signal is normal, turn to step (2).
(2) Similar to (1), when the output control signal of the vehicle controller is normal, check whether the output signal of the motor controller is normal. If the control signal output to the inverter is abnormal, repair or replace it in time.
5、 Abnormal motor speed
1) Possible causes of failure
(1) The motor controller is abnormal.
(2) Inverter is abnormal.
(3) The motor is abnormal.
2) Fault analysis
The motor controller sends control commands to the inverter, which generates three-phase AC with certain amplitude and frequency according to the control commands, and controls the motor to operate according to certain rules. If the inverter fails to send specific three-phase AC power according to the control command, it may cause abnormal motor speed fault.
3) Solution
(1) Check whether the control command generated by the inverter is normal. If not, repair or replace it in time.
(2) Repair or replace the motor in time.
6、 Door handle does not pop out automatically
1) Possible causes of failure (1) Vehicle key failure.
(2) Vehicle electronic control system failure.
(3) The door handle electronic control system is faulty. (4) The door handle transmission mechanism is faulty.
2) Fault analysis of corresponding causes
(1) Tesla judges the distance between the key and the vehicle through certain technical means. When the distance is less than a certain value, Tesla will think that the owner needs to get on the vehicle, and then pop out the door handle. If the vehicle key fails, the door handle cannot be automatically ejected.
(2) The determination of the distance between the vehicle key and the vehicle itself needs to be completed by the vehicle's electronic control system. If there is a problem with the electronic control system, the door handle cannot be automatically ejected.