New energy vehicles differ greatly from fuel vehicles. The maximum voltage of traditional fuel vehicles is only 24V, while that of new energy vehicles is as high as 500V. In the maintenance and repair of new energy vehicles, not only to meet its special structure, but also to do high-voltage electrical insulation protection work. Therefore, maintenance tools and equipment specially designed for new energy vehicles came into being.
1. Maintenance of power battery pack
Traditional fuel vehicles require regular maintenance, as do electric vehicles. Lithium battery is the heart of electric vehicle, its performance status directly determines the service life of the vehicle, and the factors that can determine the service life of lithium battery are the consistency of the battery and the number of charge and discharge cycles.
The power battery of an electric vehicle is composed of a plurality of battery cells connected in series to form a battery, and the battery cells are connected in parallel to form a battery pack, which is called PACK in the industry. During the continuous charging and discharging of the battery, the loss of each cell is uneven. Some cells will never be fully charged, while the other part will never be discharged. The greater the deviation, the worse the consistency. The battery life and battery life The service life will become shorter and shorter.
In order to prolong the service life of the power battery, the leading brand of domestic auto repair special tools, Nastda, has developed a "new energy electric vehicle endurance maintenance instrument". Compensate and charge the single battery in the PACK through an independent channel to ensure that the single battery gets completely consistent power, effectively suppress the mutual differences within the battery pack, and maintain battery consistency. Different from the traditional active balancing and passive balancing modes, there is no discharge action during battery maintenance to avoid further loss of battery life and to ensure the full life cycle of the battery pack.
2.three electrical system maintenance testing
1） Battery disassembly and transportation
The weight of a new energy vehicle's power battery can exceed 500 kilograms, and it is easy to disassemble and assemble with simple tools close to manpower. It is very easy to cause safety accidents. A slight accident may also lead to battery collision and explosion or damage to the car body. Therefore, a flexible mobile lift car is very necessary when removing and installing batteries.
The function of the lifting and disassembling tool car is mainly to undertake the positioning and disassembly of the battery after the chassis is installed. When the battery is installed, the lifting car can be adjusted to move under the car body by the control lever, and be lifted to the bottom of the car by electro-hydraulic. The X / Y / Z floating adjustment function of the upper deck can be fine-tuned. The front, rear and left and right angles can be 60mm in three dimensions It can be adjusted within the scope to realize the alignment installation of battery screws. The antistatic buffer rubber block is arranged on the flat pad, which needs to have an electrical insulation function to prevent safety accidents.
2）Battery pack coolant replacement
In the design of the cooling system of the battery pack, considering the cooling efficiency, the cooling liquid water cooling method is basically adopted. The cooling fluid is not in a static state in the battery cavity, but under the action of the water pump, the continuous flow takes away the heat emitted by the battery. During the movement, impurities due to movement friction and other factors will inevitably be generated. The continuous increase will affect the cooling effect and cause potential battery safety hazards. In this way, the coolant in the battery needs to be replaced regularly to avoid potential safety hazards caused by overheating of the battery.
The battery coolant replacement device can discharge and replace the battery pack coolant, first drain the coolant, and then add new coolant into the battery coolant chamber and discharge excess gas.
3）Air tightness monitoring
The "lithium" in the power battery is a metal with very active chemical characteristics, so the battery box used to wrap the lithium battery must be high strength, high rigidity, easy to dissipate heat, waterproof and insulated. However, when the vehicle is used and maintained, it will inevitably bump into the battery pack, so the sealing test of the battery box is very important.
When all outlets of the battery pack PACK are closed, use the device to apply positive pressure from the outside and track the leakage rate of the remaining gas for a period of time to determine the sealing of the battery pack.
4）Motor disassembly platform
As one of the three major components of pure electric new energy vehicles, drive motors are the core technology of new energy vehicle companies. When the motor fails and needs to be disassembled for maintenance, it is very difficult to disassemble, and you need to pay attention to proper shock absorption.
According to the external dimensions of the motor and the reducer, tooling fixture design is carried out, combined with the hydraulic lifting car, to ensure that the motor and the reducer can be quickly and safely disassembled. In addition, considering the need for maintenance and replacement, the motor and reducer are horizontally separated, which makes the operation more flexible. The platform has space for fork legs to facilitate the transfer of motor reducers and tools.
3. Portable charging equipment
With the increasing popularity of new energy vehicles, there may be insufficient repair stations in the maintenance process of new energy vehicles. If the station is occupied to charge the vehicle, the waiting time of the vehicle to be repaired will be extended, affecting the maintenance efficiency . The portable charging device has a small and light structure, which is convenient and fast to push. When charging, it only needs to push the device to the side of the car to remove space restrictions and effectively alleviate the problem of work station tension.
This device is an energy storage DC fast charging device, which can charge and store 20KWh of electrical energy (the full capacity of the ordinary chassis battery is about 15KWh ~ 20KWh). The electronic screen can display the current power, charging real-time current and other functions. The output is in the form of DC fast charging greater than 15KW, which satisfies the task of quick rescue. When charging, it can be directly connected to 220V through the interface to implement voltage stabilization to supplement power. The charging head is a national standard plug. After it is inserted into the car, the CMS automatically docks the electric vehicle BMS system to complete the protocol matching and charge. It has active protection and is safe and reliable.
4.computer fault diagnostic instrument
1）Computer fault detection
Because the voltage of the power battery used by the new energy vehicle is relatively high, and the power part is different from the traditional internal combustion engine, the traditional fault diagnostic instrument cannot be used, which brings difficulties to subsequent car maintenance.
"New energy vehicle computer fault diagnosis instrument", maintenance personnel can quickly and accurately determine the nature and location of the fault according to the prompt of the fault code, and check the relevant parts, components and lines in a targeted manner to eliminate the fault. Considering that electric vehicles may generate high-voltage risks during maintenance, a special high-voltage electrical protection kit is also provided to standardize safer operation. The unique charging base makes charging more convenient and can also be used as a tablet stand.
2）Electrical test table
When repairing new energy vehicles, a variety of electronic testing tools are needed to assist in testing, so as to find damaged electrical components faster.
During the operation of the car, it is inevitable that it will collide and rub, resulting in a decrease in the insulation between the high-voltage circuit and the chassis of the vehicle. Therefore, it is necessary to first check whether the insulation resistance of the high-voltage cable and parts to the body is within the specified value range.
Megohmmeter, also known as digital megohmmeter, high-voltage insulation resistance tester, insulation resistance tester, etc., is mainly used to check the insulation resistance of electrical equipment, electrical lines to the ground and between phases to ensure that these equipment, appliances and lines work normally State, to avoid accidents such as electric shock casualties and equipment damage.
The multimeter is a multifunctional, multi-range, portable electronic instrument that can measure AC, DC current, voltage, resistance and other electrical parameters. It is in compliance with CAT III safety level.
New energy vehicle maintenance diagnosis often needs to measure the current in the wire. Because the wire of the drive system has a large alternating current, a clamp type ammeter must be used for indirect testing. Clamp ammeter is a combination of current transformer and ammeter, which can measure current without cutting off the circuit.
Compared with traditional oscilloscopes, this digital oscilloscope has a built-in lithium battery, no external power supply is required during operation, and it is convenient to move, especially for on-site operation, which is more flexible. Various triggering methods are available: automatic, normal, single trigger, etc. It can quickly and accurately find problems in automotive circuits and is a good assistant for car repair technicians.
5. High-voltage electrical insulation protective equipment
1.）Maintenance station protective equipment
The maximum voltage that the human body can withstand is 36V, and the voltage of new energy vehicles is more than ten times higher than the safe voltage. In order to ensure the safety of maintenance operators, the insulation protection of the overall station cannot be careless.
The protective equipment of the maintenance station includes: battery explosion-proof box, insulated floor mat, safety fence, fire blanket, fire extinguisher, insulated rescue hook, high voltage warning sign, high voltage warning sticker, etc.
2） High voltage discharge
In addition to the above protective equipment, there is a relatively special protective equipment called "capacitor discharger". In the process of repairing new energy vehicles, it is necessary to disconnect the power battery. During the process of disconnection, high voltage electricity will remain in the entire high-voltage system, which is very dangerous. While disconnecting the power battery, a high-voltage capacitor discharger is needed to discharge the high-voltage system to ensure the safety of the operator.
3） Insulation tool
The protective equipment for operators includes: insulating shoes, insulating caps, insulating gloves, goggles and operating tools with insulating properties. Among them, tools such as torx wrenches, open-end wrenches, screwdrivers, sockets, pliers, etc. directly contact the operator, must have good insulation, and pass the quality inspection of professional institutions. Unauthorized use of non-special insulated tools is unauthorized. If there is a problem of rubber cracking or the pressure level is not up to standard, the operator may be killed.
Through the rubber hardness test and indentation test, high and low temperature resistance test, impact strength test, node strength test, flame retardant test, the quality is safe and reliable.
Maintenance work can be performed on live and near-point workpieces or devices with rated voltages of 1000VAC (AC voltage) and 1500VDC (DC voltage).
Overall heat treatment, high hardness. The handle cover is made of insulating, oil-resistant, organic solvent-resistant and corrosion-resistant materials. VDE insulated pressure tools are certified by VDE, withstand voltage of 1000V in accordance with IEC / EN60900-2012 standards, and have passed seven test items including pull-out force, flame retardancy, high and low temperature, and dielectric strength.
