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BAIC BJEV test in extremely high temperature at "Flaming Mountains"

From:Internet Info Agency 2018-09-04 19:13:27

Every time we talk about electric vehicles, there’s one question spring into our mind: "How far is the cruising range?" In fact, many people have a misunderstanding in this respect, that is, a vehicle with high rated cruising range is not necessarily able to run far. Especially in the extremely cold, extremely hot and high-altitude environment, the actual cruising range of electric vehicles will be attenuated. Turpan, located in Xinjiang Uygur Autonomous Region in northwestern China, is the largest dry and hot environment exposure test site in China. In the test area in August, the temperature reaches 44 ° C, and the land surface temperature exceeds 60 ° C, which is a huge challenge to the performance of EV. And today I will work with engineers from BAIC BJEV to see what kind of answers they will make after receiving the tough challenges of their products in the high temperature of 45 °C in Turpan in midsummer.

The high-temperature test in China is usually conducted in Hainan province and Xinjiang Uygur Autonomous Region, which are located in the southernmost area and the northwest of China respectively. This time, BAIC BJEV chose to test its models in Turpan where the annual average temperature and the annual maximum temperature are the highest and longest-lasting, and where the annual rainfall is the least.

What is the aim of testing vehicles in high temperature?

Compared to fuel vehicles, the motor, battery, and electronic control system of pure electric vehicles is more sensitive to temperature. Especially in a high-temperature environment, the working status of the battery and the performance of the vehicle will be greatly affected, and even the charging speed will be greatly slowed down. Once the battery continues to overheat, there is even a risk of spontaneous combustion. Therefore, it is vital for EVs to control their own temperature in a high-temperature environment.

How is the test being conducted?

After some detailed and efficient training, we can't wait to come to the test site to start testing. The protagonist of this time is the upcoming model of BAIC BJEV. (currently, is the engineering test car)

Turpan is also called “Flaming State” where the high temperature and drought has caused the grass and trees to be difficult to grow. On the testing day, the land surface temperature reached 64.2 ℃.

The sun's exposure heats the land surface to an extremely high temperature, enabling eggs to be fried without fire under this kind of environment.

Since the local traffic control department does not allow the test vehicles to enter the downtown area of Turpan, it is necessary to apply for a pass in the on-site test.

The high-temperature test is not simply expose vehicles under the sun blindly. It has to use devices to test the sunlight intensity.

The sensors on the body are used for thermal balance tests to test the performance of the vehicle under high temperature conditions and whether some parts will have other changes or be invalid in the high-temperature environment.

The sensors used to test the internal temperature are placed at the center console, the rear seats', the feet area and the roof.

Sensors are also placed outside the body and in the engine compartment to record real-time temperatures.

Since the temperature is varying inside the car, in order to check the temperature of the passenger's possible position, sometimes the temperature sensors were had to be placed on the engineer's head, left and right shoulders, left and right hands, left and right knees and legs. And at this time, the total number of sensors placed will reach more than 100.

Regardless of quick charge or slow charge, starting and charging in a high-temperature condition is an indispensable test for NEVs.

The thermometer was placed inside the car for 5 minutes and the reading showed that the temperature inside the car reached an astonishing 72.2℃. Sitting in the car in such an environment, only 3-5 seconds will the passengers feel uncomfortable and even unable to breathe.

Engineers of BAIC told us that the high-temperature test of BAIC BJEV will last 40 days, the hottest time from July to August. The road test is about 8000 kilometers in total, that means driving almost five or six hundred kilometers a day under the hot environment is needed. Sometimes, air conditioners are not allowed to be turned on for testing accuracy.

Pulling & Sand and Dust Test

Even though there is beautiful scenery at Gobi deserts, engineers have no time to enjoy it. They need to travel to and from such sections of roads every day for carrying out various tests, data collection, and inspection of vehicles rigorously. What they can feel most is tedious work.

Pulling test refers to using a tow rope to connect the front and rear vehicles. During the driving process, the rear car brakes intermittently which is to quickly increase the load and heat up the motor to check the working conditions of the front vehicle in such situations.

Meanwhile, engineers need to bring GPS devices to record the real-time location of the vehicle, and the recorded driving track also helps engineers to troubleshoot the fault.

Although the air conditioner was turned on during the driving process, as long as it was off, the inside temperature would rise from more than 30℃ to more than 40℃ in a few minutes. The big internal and external temperature difference makes passengers easy to catch a cold.

When the vehicle is driving in a high-temperature condition, the discharge power of the battery pack, the motor temperature and the output power of the motor will be affected. In order that the system can better adapt to a high-temperature environment, it is essential to test the best condition and operating efficiency of the vehicle in high-temperature conditions.

At the same time, Turpan is also a best site for sand and dust test. The sand here is thinner than that in other places which can be used to examine the sealability of the vehicle.

When conducting sand and dust test, the smell of the dust will not be noticed inside the car when air conditioners are in closed-loop. After the test, no obvious sand and dust can be seen at air vents, interior door frame and floor margins.

Summary

The safety of EVs is the result of complex technologies and technological achievements, and it is also a comprehensive test for the overall integrated R&D system of automotive manufacturers. As a veteran new energy company, it can be seen that BAIC has a completed high-temperature test system to verify and calibrate its own products. Through this test in Turpan, we can see that how a pure electric vehicle maintains its stable performance in an extremely hot environment. The cruising range and the safety performance of a vehicle in extreme environments are all important inspection indexes for EVs.

Editor:Zhang Jiawen