The Mercedes-Benz Vision EQXX did not cause such a big sensation as it did at the CES Electronics Show in North America earlier this year.
As a concept car, the parameters were not "science fiction" at that time: the official endurance exceeded 1000km!? This gimmick, hasn't there been a mass production car blown in China? Wind resistance coefficient as low as 0.17!? Isn't there a concept car in China that has achieved 0.146? Solar Charging!? It costs a few thousand dollars in China to choose it.
Co-author of a global luxury car leader, the inventor of the car to build a latest pure electric concept car at this level? If it is placed on a production car, is it not necessary to pull more spans and more spans? Therefore, this Mercedes-Benz Vision EQXX concept car not only did not change the image of Mercedes-Benz lagging behind in the field of electrification, but also deepened.
In the face of these doubts, Mercedes-Benz is also not much to say, directly pull this concept car to the real road conditions, let everyone see what is "mouth hi", what is practical!
Some time ago, this Vision EQXX concept car departed from Sindelfingen, Germany, and traveled 1008 kilometers with only "one box of electricity" to reach Cassis in France. In order to prove that the endurance of this journey is not made by professional riders in a very ideal environment with the running method of the energy-saving competition, Mercedes-Benz also gave some test conditions.
First, this journey is not very comfortable for electric vehicles - not only to walk through high-speed, mountain roads and other road conditions, but also to face the minimum of 3 degrees Celsius, the highest 18 degrees Celsius of extreme temperature difference. High speed, climbing, low temperature, can be regarded as the three major killers of pure electric vehicle endurance.
Second, the journey took 11 hours and 32 minutes, the average speed went to 87.4km/h, and the top speed was even as high as 140km/h, in other words, they did not deliberately use the economic speed to drive at a uniform speed to save energy consumption. After arriving at the destination, the Vision EQXX has not run out of food, with about 15% of the remaining power and about 140km of remaining cruising range.
In other words, even an ordinary person, in a relatively normal environment, can run this 1000km endurance.
Although the Vision EQXX has run the longest range in the current pure electric vehicle, its battery capacity is not the largest on the market, even less than Mercedes-Benz's own EQS, and the available power is only 100kWh.
In contrast, the AION LX PLUS and NIO ET7 run out of 1000km under NEDC conditions and require 150kWh of batteries to support it. It should be noted that the NEDC working conditions they are in are a very ideal working condition, put on the normal road, their endurance also has to be about a 30% discount, just like AION LX PLUS, many media measured out is 700-800km.
Although the battery capacity of the Vision EQXX is large, the volume and weight are very small, of which the volume energy density is increased to 400Wh/L, which is about twice the level of the current power battery.
There are many ways to improve the battery life of an electric vehicle, the simplest of which is to increase the capacity of the battery. However, with the increase of battery capacity, the weight of the car will also increase, the marginal effect will decrease, and eventually a lot of batteries may be added to increase the endurance of a little: Weilai ET7 will increase the endurance from 500km to 700km, only need to increase the power of 25kWh, but from 700km to 1000km, it is necessary to increase the power of 50kWh, and it is rolled up first.
Blindly using battery capacity to improve endurance, honestly, not very smart, nor scientific. The Mercedes-Benz Vision EQXX proves one thing: energy efficiency is the most effective way to improve battery life. As the Chief Technology Officer of Mercedes-Benz put it: "Energy efficiency is the 'hard currency' of pure electric vehicles." ”
In order to improve the energy efficiency of the Vision EQXX, Mercedes-Benz can be said to use every means to improve the efficiency of the vehicle, and most likely reduce the driving resistance it is subjected to.
Among the many driving resistances, the first thing mercedes-benz engineers need to solve is air resistance. At high speeds, two-thirds of the vehicle's drive is used to overcome air resistance. As you can see, the Vision EQXX has a drag coefficient of only 0.17. You know, its battery cooling method is air cooling that has a negative impact on the wind resistance coefficient - it will probably increase by 0.007.
What is the approximate level of the wind resistance coefficient of 0.17? While this isn't the lowest of the concept cars, it's definitely one of the best cars that can run on the road. The Volkswagen XL1, which claims to be able to run 100km with 1L of oil, has a drag coefficient of 0.189. This is the car I have ever seen that can legally hit the road, and the car with the least wind resistance coefficient.
From the Vision EQXX's eerie body lines, fully enclosed wheels, to the complex rear diffuser...... You probably know how much mercedes-Benz has done to optimize its aerodynamics, and even they have indented the rear wheelbase by two inches (about 5cm) to make the air transition to the tail more smoothly.
Of course, the lower the wind resistance coefficient, the less it is affected by air resistance, and it does not mean that its air resistance is also small. According to the calculation formula of air resistance, in order to really reduce air resistance, in addition to reducing the wind resistance coefficient, it is necessary to reduce the windward area.
Mercedes-Benz did not say what the windward area of the Vision EQXX is, but he mentioned that its windward area is smaller than that of both CLA and Smart vehicles. You know, the Vision EQXX length, width and height are 4977x1870x1350mm, the wheelbase reaches 2800mm, a proper C-class car, and smart is mostly small cars and mini cars.
In addition to aerodynamics, the weight of the vehicle also has a great influence on drag – in addition to aerodynamic resistance, rolling resistance, acceleration resistance and ramp resistance are all directly related to vehicle weight. If the optimization of aerodynamics tests the design ability of Mercedes-Benz, then the weight reduction tests in addition to Mercedes-Benz's engineering capabilities, as well as its "banknote capabilities".
On the Mercedes-Benz Vision EQXX, you will find a lot of new materials.
For example, the power battery we just mentioned, whose shell directly uses the technology from the Mercedes-Benz F1 race car, is constructed with a composite material taken from sugarcane waste, which greatly reduces the quality of its battery. In the end, the entire battery pack of the Vision EQXX weighed only 1091 pounds, or less than 500 kilograms. In contrast, the 100kWh battery pack weighs 555kg.
For example, the Vision EQXX uses MS1500 ultra-high-strength martensitic steel to create a body-in-white body that minimizes weight while ensuring stiffness and safety. Many people may not have any concept of this steel with a strength of 1500MPa. For reference, the strongest A-pillar on the Tesla Model 3 is only 1300MPa of thermoformed steel.
For example, the Doors of the Vision EQXX are made of a mixture of carbon fiber, fiberglass and aluminum alloys. This kind of door is not only stronger and lighter than the simple aluminum alloy door, but also maintains a relatively good elongation, avoiding the fragility of carbon fiber and glass fiber against radial impact forces.
For example, the entire chassis of the Vision EQXX is mostly made of aluminum alloy: a lightweight subframe taken from F1, a brake disc made of aluminum, an integrated cast aluminum rear floor... In addition, in order to improve the stiffness and sound insulation effect of the integrated casting, and further reduce the quality of the whole vehicle, Vision EQXX also uses a 3D printer to manufacture UBQ sealing patches.
Through the efforts of all parties, the vision EQXX with a length of nearly 5 meters has a curb weight of only 1755 kg, which is comparable to a fuel version of the Mercedes-Benz E-Class. Also a pure electric vehicle, the size of the WEILAI ET7, the maintenance quality has gone to 2.35 tons, even if this is the longest endurance of the WEILAI ET7, it is about 33% heavier than the Vision EQXX.
Air resistance, lightweight, it is estimated that many OEMs know that this is the pain point of electric vehicles, but also looking for ways to improve it. But another way to improve the energy efficiency of electric vehicles is often overlooked by OEMs, that is, to improve the transmission efficiency of the system. As the leader of the F1 Grand Prix, Mercedes-Benz is all too aware of the flow of energy per joule: the efficiency of the mechanical transmission is a part that cannot be ignored.
To this end, when Designing each system, Mercedes-Benz will minimize the loss of the system from the aspects of system design, material selection, lubrication and thermal management, thereby improving the transmission efficiency of the system.
Ultimately, the Vision EQXX drivetrain is 95 percent efficient, which means that 95 percent of the battery energy is directly applied to the wheels and is involved in driving. In contrast, even the most efficient internal combustion engine drive system on the market today has a transmission efficiency of only 30% - which is understandable, after all, the combustion loss of the internal combustion engine alone is about 60%.
In order to make full use of this 95% of energy, Mercedes-Benz also hired Bridgestone to jointly develop a set of ultra-low rolling resistance tires - the lightweight environmental protection ENLITEN and ologic technology into Bridgestone's Tuanza Eco tires, reducing the rolling coefficient of the tires to 4.7. For reference, Michelin's PILOT SPORT 4 has a rolling resistance coefficient of 8.6.
The Vision EQXX, which achieves the ultimate energy efficiency, in this journey, the comprehensive power consumption of 100 kilometers is only 8.7kWh, and the energy consumption is almost the same as that of a Hongguang MINI EV, which is really unbelievable!
Undoubtedly, the Vision EQXX journey has refreshed the energy consumption level of an electric vehicle, allowing people to see the technical reserves of Mercedes-Benz in the field of electric vehicles. It has also once again proved that the so-called new car-making forces actually have no advantages in pure electric vehicles, and traditional car companies still have great potential with their long-term accumulation.
Of course, while affirming Vision EQXX, we must also look at its practical significance dialectically.
Although I took a lot of production cars to compare above, explaining the level of energy efficiency of vision EQXX, it is undeniable that it is only a concept car, and many of the technologies in it may not be seen on the market for a long time, or quite expensive, and it is not affordable for ordinary people.
For example, the vision EQXX uses a post-diffuser that plays a key role in the aerodynamics, even if you can afford to buy it, it is estimated that you will not be able to repair it - after all, the rear of the car is the most vulnerable place in a car, and it is estimated that no old driver has not tried the "hip" hanging color.
For example, its aluminum brake discs, its carbon fiber doors, its one-piece cast aluminum floor, its solar charging panels... All of this, either unsurable, expensive, or without the economics of maintenance, is of little value for converting into a commodity.
But in any case, with the Vision EQXX's journey of a thousand kilometers, Mercedes-Benz finally let people see its advantages in electrification, and tell everyone that what is called your uncle is still your uncle.
Text | Male
(This article is the author's personal opinion only and does not represent the position of DearAuto.) )
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Mr. Li Guoyong of Guangdong Green Law Firm