2019-05-15 New energy vehicle maintenance faces new challenges In recent years, the new energy automobile industry has developed rapidly. According to the data, in March 2019, the national passenger vehicle market retail sales reached 1.74 million units, down 12.1% year-on-year. However, new energy sales rose to 111,000 units against the market, a year-on-year growth rate of 100.9%. The surge in sales of new energy vehicles has also created new challenges for the automotive aftermarket.

New energy vehicles differ greatly from fuel vehicles. The voltage of traditional fuel vehicles is only 24V, while the voltage of new energy vehicles is as high as 500V. In the maintenance and repair of new energy vehicles, not only must it meet its special structure, but also do a good job of high-voltage electrical insulation protection. Therefore, repair tools and equipment designed for new energy vehicles have emerged.

First, the maintenance of the power battery pack

Traditional fuel vehicles require regular maintenance, and electric vehicles are also needed. Lithium battery is the heart of electric vehicles. Its performance status directly determines the service life of the vehicle. The factors that determine the service life of the lithium battery are the consistency of the battery and the number of cycles of charging and discharging.

The power battery of an electric vehicle is composed of a plurality of single cells through a series of cells, and a plurality of cells are connected in parallel to form a battery pack, which is called PACK in the industry. During the continuous charging and discharging process of the battery, the loss of each single cell is uneven, some of the single cells are always full, and the other part is never filled. The greater the deviation, the worse the consistency, and the battery life of the battery pack over time. The service life will also be shorter and shorter.

In order to extend the service life of the power battery, Nasida, a leading brand of domestic automotive maintenance tools, has developed a “new energy electric vehicle maintenance maintenance instrument”. The single channel battery in the PACK is compensated and charged through the independent channel to ensure that the single battery has a completely consistent power, effectively suppressing the mutual difference between the battery groups and maintaining the battery consistency. Different from the traditional active equalization and passive equalization modes, there is no discharge action during battery maintenance, which avoids further loss of battery life and ensures the life cycle of the battery pack.

Second, three electric system maintenance testing

1. Battery disassembly and handling

The power battery of the new energy vehicle can weigh more than 500 kilograms. It can be dismantled and installed with simple tools. It is very prone to safety accidents. A slight accident may cause the battery to collide and explode or damage the car body. Therefore, a flexible mobile lift truck is necessary when disassembling the battery.

The function of the lifting and disassembling tool cart is mainly to bear the positioning of the battery after the chassis is installed. When the battery is installed, the lifter is adjusted to the underside of the vehicle through the control lever, and is lifted to the bottom of the vehicle by electro-hydraulic lifting. The X/Y/Z floating adjustment function of the upper plate can be fine-tuned, and the front, rear and left and right angles can be 60mm in three-dimensional space. Adjustment within the range to achieve the alignment of the battery screws. An anti-static cushioning rubber block is placed on the flat pad and needs to be electrically insulated to prevent a safety accident. It is worth mentioning that this disassembly and assembly vehicle adopts domestic hydraulic pump station, high-quality battery and charger. It only needs to press the remote control button to realize automatic walking. It does not need manpower, which can effectively reduce labor intensity and improve work efficiency. . Moreover, when moving, the speed is limited, making the handling more stable and ensuring the safety of the battery.

2. Battery pack coolant replacement

The battery pack is designed for the cooling system. Considering the cooling efficiency, the coolant is water-cooled. The coolant is not in a static state in the battery chamber, but under the action of the water pump, it constantly flows, taking away the heat generated by the battery. During the movement, impurities are inevitably generated due to factors such as motion friction, and impurities will change with time. Constantly increasing, affecting the cooling effect, causing potential battery safety hazards. In this way, the coolant in the battery needs to be replaced periodically to avoid potential safety hazards caused by overheating of the battery.

The battery coolant replacement device can discharge the battery pack coolant, first discharge the coolant, and then fill the new coolant into the battery coolant chamber to discharge excess gas.

3. Air tightness monitoring

"Lithium" in the power battery is a very active metal, so the battery case used to wrap the lithium battery must be high strength, high stiffness, easy to dissipate heat, waterproof and insulated. However, when the vehicle is used and repaired, it will inevitably hit the battery pack, so the sealing test of the battery case is very important.

In the case where each outlet of the battery pack PACK is closed, the device is used to determine the leak tightness of the battery pack by applying a positive pressure from the outside and tracking the leak rate of the remaining gas over a period of time.

This device can be used not only for battery pack air tightness detection, but also for motor air tightness detection. Most of the motors equipped with electric vehicles are water-cooled motors. In order to ensure the effect of water cooling, the flow rate of water cooling has strict requirements according to the design of motor power, and the water channel may need to bear a large pressure. Moreover, the outer casing is generally completed by casting, so this may cause trachoma in the outer casing, which may cause high pressure and micro leakage. The traditional soaking water detects the sealing performance of the water-cooled motor, the efficiency is low, and it is not intuitive, and some sealing problems are difficult to find. As a new sealing detection technology, air tightness testing first pressurizes the motor according to the test requirements, sets the test time and the allowable discharge flow, and the detection process is simple and the test time is short.

4. Motor disassembly platform

As one of the three major components of pure electric new energy vehicles, the drive motor is the core technology of new energy vehicles. When the motor fails and needs to be disassembled for fault repair, it is very difficult to disassemble, and it is necessary to pay attention to proper shock absorption.

Third, portable charging equipment

With the increasing popularity of new energy vehicles, there may be a shortage of maintenance stations during the maintenance and repair of new energy vehicles. If the station is used to charge the vehicles, the waiting time of the vehicles to be repaired will be extended, which will affect the maintenance efficiency. . The portable charging device has a compact and light structure, which is convenient and quick to push. When charging, it is only necessary to push the device to the side of the vehicle, thereby lifting the space restriction and effectively alleviating the problem of station tension.

This equipment is a storage energy DC fast charging device, which can store 20KWh of electricity (the normal chassis battery is about 15KWh~20KWh). The electronic screen can display the current power, real-time charging current and other functions. The output is a DC fast charge form of more than 15KW, which meets the fast rescue mission. When charging, it can be directly connected to 220V through the interface to implement voltage regulation to supplement the power. The charging head is a national standard plug. After the car is inserted, the automatic CMS docking electric vehicle BMS system completes the protocol matching and charging, and has an active protection function, which is safe and reliable.