The maintenance of pure electric vehicle power supply system includes routine maintenance, key maintenance, storage maintenance, etc. Maintenance personnel must wear protective equipment such as insulating gloves when operating, and must be familiar with the structure, working principle and operating instructions of the power supply system before use.
- Maintenance preparations and precautions
(1) Preparation for maintenance
In the process of vehicle overhaul and power system maintenance, the following preparations need to be done.
①Preparation of special tools.
a. Overhaul the instrument. Some electric vehicles are equipped with special maintenance equipment.
b. Commonly used instruments. Such as insulation tester and so on.
c. Special tools. Such as screwdrivers, wrenches, etc., these commonly used tools must have insulation measures.
e. Common materials. Such as insulating tape, cable ties, etc.
f. Possible special equipment. such as chargers, etc.
Pure electric vehicles use high-voltage circuits, and personal protective measures must be taken before maintenance.
a. Wear insulating gloves.
b. Wear insulating shoes, work clothes, etc.
c. Metal objects, such as metal bracelets, rings, watches, necklaces, etc., cannot be worn on the body.
(2) Maintenance precautions
Pure electric vehicle systems use high-voltage circuits, and improper operation may result in electric shock or leakage. Therefore, in the maintenance process (such as installation, disassembly, inspection, replacement of parts, etc.), the following matters must be paid attention to.
①Before overhauling, you must be familiar with the vehicle manual and power system manual.
② Disconnect the power supply when operating the high-voltage system. When disconnecting the power supply, it should be noted that the fault code in the high voltage or auxiliary power supply system may be cleared, so it is necessary to check and read the fault code before disconnecting the power supply.
③ Disconnect the power and leave the vehicle for 5 minutes. High voltage capacitors within the vehicle system need to be discharged.
④ Wear insulating gloves, and make sure that the insulating gloves are not damaged. Do not wear wet gloves.
⑤ The wiring harness and connectors of high-voltage circuits are usually orange, and high-voltage components are usually marked with “high-voltage” warnings. Special attention should be paid when operating these wiring harnesses and components.
⑥ When operating the high-voltage system, place a warning sign of “High-voltage work, do not approach” beside it.
⑦Do not carry any metal objects like calipers or measuring tapes, as these objects may fall and cause short circuits.
⑧ Immediately after removing any high-voltage wiring, wrap it with insulating tape to insulate it.
⑨ Be sure to tighten the high-voltage screw terminals according to the specified torque. Insufficient or excessive torque can lead to failure.
⑩ After completing the operation of the high-voltage system, it should be confirmed again that there are no parts or tools left around the working platform, and that the high-voltage terminals have been tightened and the connectors have been connected.
- Regular maintenance of the power source
Routine maintenance is to check and eliminate potential safety hazards that affect the use of the power supply to avoid dangerous accidents. By formulating a routine preventive maintenance plan, you can better understand the health status and end life of the battery used, and determine the replacement of the battery. or a focused maintenance plan. Routine maintenance is generally performed once a month. For more information on battery maintenance, please visit tycorun.com.
(1) Maintenance procedures
①After the power supply system is used for 1~2 months, the maintenance personnel need to maintain the appearance and insulation of the power supply system.
②After the power supply system has been used for 3 months, the following matters should be paid attention to when performing a charge-discharge maintenance on the power supply system if possible.
a. Maintenance personnel must wear protective equipment such as insulating gloves when operating, and must be familiar with the structure, working principle and usage of power supply products before use.
b. When performing charging and discharging maintenance, connect the power supply system in place according to the normal working requirements, turn on the power supply of the management system, monitor the status of the battery, and determine the ambient temperature, battery temperature and battery voltage status of the battery according to the monitored data. Is it normal.
c. Before performing charge and discharge maintenance, the operator should first check the condition of each part of the power supply system, and then perform charge and discharge maintenance only after ensuring that each part is normal.
d. Maintenance should be carried out in an environment with a temperature of 15~30℃, a relative humidity of 45%~75%, and a pressure of 86~106kPa.
e. During the charging and discharging maintenance process, check whether the function of the management system is running normally.
f. During the charging and discharging maintenance process, check whether the fan is turned on and off at the specified temperature, and whether the operation is normal.
g. After the charge and discharge maintenance is completed, check the insulation resistance of the battery pack. The measured insulation resistance should meet the requirements of the index. Use a voltmeter to measure the positive terminal, negative terminal and the maximum voltage of the battery pack respectively. At the same time, the measured voltage The value should not exceed the upper limit requirement.
h. After maintenance, the power supply system can be used only if the functions of the power supply system are normal; if there are abnormal conditions and faults, they should be eliminated immediately, and if there are any faults that cannot be eliminated, the manufacturer should be contacted in time.
(2) Maintenance content
①Check the status of the power supply system.
②Check whether the function of the management system is normal.
③ Charge and discharge the battery for maintenance.
(3) Maintenance method
Check the appearance of the power supply system as follows. If there is any problem, it should be eliminated in time. If it cannot be eliminated, please contact the manufacturer in time.
a. Check whether the battery pack box is in good condition and whether there is damage or corrosion.
b. Check whether the bolts and nuts of each fastener are loose.
c. Check whether the connecting wires between the battery packs are loose.
d. Check whether the plug is in good condition, whether the various wiring harnesses are damaged or scratched, and whether there is any exposed metal part.
e. Check whether the cooling channel of the battery pack is abnormal.
②Insulation. Disconnect the high-voltage connection between the battery pack and the vehicle, and use a digital multimeter to measure whether the voltage of the total positive and total negative terminals of each battery pack to the vehicle body is less than the upper limit. If the voltage is found to be too high, measure whether the battery pack box is insulated from the vehicle body. If there is any problem, it should be repaired by professionals. It is usually possible to roughly confirm which of the power supply systems composed of multiple battery packs has a problem with the insulation of the vehicle body according to the voltage of the total positive and total negative terminals of the system to the vehicle body: by measuring the voltage of the total positive and total negative terminals of the battery pack to the battery pack shell It is possible to roughly determine the battery module with insulation failure in the battery pack.
For example, for a battery pack composed of 60 NiMH batteries, the normal voltage of the battery pack is 75V (the sum of the voltages of 600 batteries). If the voltage of the total positive terminal to the battery case is 28V, it can be roughly judged that the total positive terminal is from the total positive terminal. There is leakage between the 22nd and 23rd batteries (single cells) (75÷60=1.25, 28÷1.25=22.4), unpack for inspection, check the leakage point and eliminate it. If there are multiple leakage points in the same battery pack, serious discharge of some batteries (internal short circuit) may occur in the battery pack, which can be eliminated one by one according to the above method. If the insulation performance test is normal, then perform charging and discharging maintenance.
③Battery and management system
a. Turn on the battery management system, collect and record the total voltage of the battery pack, the voltage of each battery module and the temperature of each battery module in the open circuit state.
b. Carry out a charge and discharge test on the system according to the charge and discharge system recommended by the manufacturer.
c. Check whether the current, voltage, temperature and SOC displayed by the battery management system are normal during the charging and discharging process: During the normal operation of the vehicle, check whether the data display of the management system is normal; shop to complete).
d. Auxiliary power supply, run the vehicle until the cooling system works, and observe whether the cooling channel is unobstructed.
e. Check whether the connection between the management system and each part is loose.
④ Cooling system. Check whether the air inlet and outlet channels are smooth and whether the fan can work normally. Remove dust and debris on the dust filter, or replace the dust filter.
①When the power supply system is in use, its positive and negative poles must be correctly identified, and it must not be reversed or short-circuited: the power supply should be carried out according to the specified charging conditions.
②It is recommended to charge at an ambient temperature of 0~30℃.
③ When the power supply system is in use, the discharge termination voltage should be strictly controlled, not lower than the discharge voltage. Otherwise, problems such as battery performance and cycle life degradation will be caused.
④ The connection of the power source system should be firm and reliable, and the power battery should avoid working in an upside-down state.
⑤ Avoid overcharging the power battery for a long time.
⑥If the ambient temperature is too high or too low, it will have adverse effects on the charging efficiency, discharge capacity, voltage stability and service life of the power supply system.
⑦ If the power supply system is abnormal during use, the power supply should be disconnected immediately, and the manufacturer should be contacted for maintenance in time.
⑧ It is strictly forbidden for metal or wires to contact the positive and negative poles of the power supply system at the same time to avoid short circuit. A fully charged power supply system should prevent short circuit, otherwise it will seriously damage the battery and even cause danger. During transportation and use, do not damage or disassemble the battery pack to avoid short circuit of the battery pack.
⑨ The power supply system should be stored in a dry and ventilated environment with a temperature not higher than 35°C. Do not approach the fire source and avoid contact with acid or other corrosive gases.
⑩ During the charging and discharging process of the power supply system, if there is an odor or abnormal sound, the charging and discharging should be stopped immediately.
- Key maintenance of power system
The key maintenance is to carry out more detailed tests and inspections on the power supply system. The purpose is to ensure that the power supply system meets the requirements of continuous use, eliminate the potential safety hazards in the system, and prolong the service life of the power supply system. Key maintenance is generally carried out once every 6 to 8 months. Check the routine maintenance before the key maintenance
Remove the battery pack from the car. If the battery pack is installed in a suitable position on the vehicle, it is convenient for unpacking inspection and maintenance, and it is not necessary to disassemble it.
① Observe the appearance of the battery pack to see if there are signs of burning, leakage, impact, etc.
②Unscrew the fixing screw on the upper cover of the battery pack, remove the upper cover of the battery pack, and open the battery pack.
(3) Check and handle the internal condition of the battery pack
①Insulation testing. Use a digital multimeter to measure whether the voltage of the total positive and total negative terminals of each battery pack to the vehicle body is less than the specified value. If the voltage is found to be too high, find the leakage point, replace the insulating parts or take remedial measures to eliminate potential safety hazards.
② Check the chassis and bracket of the battery pack for abnormalities such as electrolyte and accumulated water. If these abnormalities exist, the battery needs to be replaced, and the installation site of the battery pack should be cleaned at the same time to ensure the insulation between the battery pack and the chassis.
③ Observe the cleanliness of the appearance of the battery and whether there is leakage or corrosion. At the same time, use a brush and dry cloth to clean the battery surface and parts.
④ Check whether the connection between the batteries is loose, rusted, etc., and clean or replace it in time.
⑤ Check whether the connection of the output terminals of the system and the connectors of the battery management system are firm, if any looseness is found, they should be tightened.
⑥Clean the dust or sundries on the dustproof net: For the cooling system with external air intake, if the power supply system is used for a long time, a large amount of dust may accumulate in the battery pack, etc., it must be cleaned up, and the insulation test should be carried out again after cleaning.
⑦ Check the appearance of each battery, whether there is damage, leakage, serious deformation, etc., mark these batteries, and replace them.
⑧ Detect the voltage of each battery, and maintain or replace the battery with abnormal voltage.
⑨ Inspection of data acquisition system.
a. Check whether each connection is firmly connected.
b. Check whether the solder joints are loose or desoldered, otherwise repair welding.
- Storage and maintenance
Storage maintenance is to test and inspect the power supply system for long-term storage (over three months), the purpose is to avoid the performance degradation caused by the long-term non-use of the battery, and to eliminate the potential safety hazards of the battery pack.
(1) Environmental requirements
Ambient temperature range: 15~30℃.
Ambient relative humidity range: maximum 80%.
(2) Maintenance method
If possible, perform a full charge and full discharge of the power supply system to activate the battery performance. Generally, charge and maintain the battery without discharge equipment. Fully charge the power supply system according to the conventional charging method or the charging method recommended by the manufacturer. For long-term storage battery, the first charge must be carried out with a small current. The main purpose is as follows: All kinds of batteries are not suitable for storage at lower voltages, and regular replenishment of electricity will improve the storage performance of the battery: adjust the voltage consistency of the battery through charging.
For lead-acid batteries, the amount of charge is generally kept at a fully charged state during storage. For nickel-metal hydride batteries, it is generally maintained at 20% to 60% of the charge. For lithium series batteries, it is advisable to keep the charge at 40%~80%.
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