NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design

Many people may remember that when NIO ET9 was released in the middle of the year, the SkyRide chassis gave the industry a small shock, but before the ET9 was officially launched, ET7 was still NIO’s flagship executive car currently on sale. In the comparison with the Mercedes-Benz E-Class and BMW 5 Series of the same level, the ET7 has achieved a level that is not inferior at all, and now we have to see if its mechanical quality and hardware level can carry the banner of the brand’s administrative benchmark.

图片[1]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

■ Chassis front structure

Since entering the NT2.0 era, NIO’s overall hardware quality has improved for all. As the first sedan to use the NT2.0 new platform, the NIO ET7 we photographed this time (parameter |Inquiry) The 100kWh executive version, which is also the second top model in the car series, is equipped with a front permanent magnet rear asynchronous dual-motor four-wheel drive system. Before the official start, we have to mention a few technical details about the ET7 body-in-white.

图片[2]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

As a medium and large executive sedan positioned as a luxury pure electric, the curb weight of the ET7 is about 2.3 tons, and the total weight of the ET7’s steel-aluminum hybrid structure body-in-white is nearly 445kg, including 39.8% aluminum and 60.2% steel. Among them, high-strength steel and ultra-strong steel account for 73%, and submarine-grade hot-stamped steel accounts for 44% in the upper body structure.

图片[3]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[4]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

Therefore, first of all, in the front part of the car, we can see some details that are almost costless, such as the longitudinal beam penetrated by the half-axle is reinforced with high-strength castings to reinforce the “notch”, making it even stronger than the original stringer design. Another example is the Torque box torque box structure that has been passed down from NIO’s successive generations of models, through a complex one-piece casting structure, the front is connected to the front longitudinal beam, and the rear is connected to the door sill beam, the A-pillar substructure and the lower footrest position, which firmly ties the four key collision force transmission paths directly in front of the body, which can effectively transmit energy to the transmission path, especially in a small offset collision environment of 25%, which can effectively avoid the intrusion of the rear passenger compartment.

图片[5]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[6]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

The front suspension of the vehicle adopts a double wishbone structure common in luxury cars, all control arms are made of forged aluminum parts, and the upper and lower control arms are designed with double ball heads, and the entire structural layout is very similar to Volkswagen’s high-end MLB Evo platform. The structural design of the virtual kingpin can further improve the precise driving experience. The intersection of two independent swing arms forms a virtual kingpin, which changes with the rotation of the wheels during the steering process, and the position of the steering point can be closer to the wheel center, thereby enhancing the ability to resist longitudinal force fluctuations, and achieving a more stable driving experience under extreme conditions such as sharp acceleration and sharp turns. It is worth mentioning that the ET7’s front lower control arm is also equipped with hydraulic bushings with carbon fiber subparts, which provides both handling and comfort, and also greatly improves durability.

图片[7]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[8]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

The shock absorber adopts a combination of CDC + air suspension, and the suspension has three heights of -10mm/0/40mm and adjustable damping. It should be noted that vehicles with air suspension must turn on the “tire change mode” or “lift/maintenance mode” in the car machine before lifting to protect the air spring air bag.

图片[9]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[10]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[11]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[12]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[13]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

The top of the shock absorber tower also adopts die-cast aluminum alloy technology, which has guaranteed strength, and the only drawback is that it is expensive. The front axle brake system is made of opposing four-piston calipers from the well-known Brembo, and the inner walls of the wheel arches are made of soft fiberglass, which is further optimized by the special design of the material and pattern. In addition, the front axle of this car uses a full-frame subframe made of double-layer stamped steel plates, and the permanent magnet synchronous motor of the front axle is covered with thick soundproof cotton, which shows that a lot of effort has been made in terms of NVH.

■ Chassis rear structure

Coming to the rear of the vehicle, the NIO ET7 has a much higher aluminum content here than the front part. The first thing that introduces the eye is that the rear axle part adopts the full-frame rear axle subframe made of integrated hollow cast aluminum technology, which has high strength, light weight, and can also control the total weight well with the larger rear axle asynchronous motor. In addition, the subframe and body connection of the rear axle are made of hydraulic rubber sleeves with better vibration resistance and higher cost. The rear axle asynchronous motor is also covered with a large area of soundproof sponge, and the thickness of the sponge is considerable.

图片[14]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[15]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[16]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[17]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[18]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

In terms of rear suspension, the NIO ET7 adopts a set of H-arm multi-link structure similar to the integrated connecting rod, and you can see that the huge H-shaped lower control arm at the bottom is connected by a short integrated connecting rod and bearing housing, and the layout is very complex. Like the front axle, except for the front beam angle control tie rod, all control arms are made of aluminum alloy, which is very costly. The entire rear suspension adopts a spring-barrel separation arrangement, and the CDC shock absorber supplier is from ZF, which is made in South Korea, and can complete the maximum damping force adjustment of 6,000 Nm in just 0.01 seconds.

图片[19]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

图片[20]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

The braking system on the rear axle is also from Brembo, but the brake calipers use the usual single-piston floating structure and integrate an electronic parking motor. The air pump of the air spring is located on the front side of the suspension system, the rear area of the battery pack, and the compressed air enters the electronic valve body on the left through the purple pipeline, and then pressurizes the air springs of the four wheels through the four colored pipelines, while the black wire pipe stores the excess air in the gas tank located at the rear of the body, and returns to the valve body through here when necessary, and distributes it to the four wheels.

■ Some other details

In other aspects, considering that the NIO ET7 is a tram, its chassis flatness is beyond doubt. When the chassis guard is not removed, the flatness of the entire bottom of the car is incomparable to that of any oil car.

图片[21]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

In addition, NIO has also considered the protection ability of the battery very thoughtfully, this 100kwh large battery cell is provided by CATL, and the design and packaging of the battery are completed by NIO. In order to take into account the needs of battery swapping, the battery pack and body frame have been double-strengthened. All NIO models use high-strength multi-chamber extruded aluminum sills, which form a strong structure with body floor beams, and the lateral strength can withstand 300KN pressure, covering both sides of the entire high-voltage battery module, providing the first line of safety.

图片[22]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

The shell of the battery is also made of high-strength aluminum material, with double-layer aluminum plate protection and a very strong honeycomb structure, optimizing the mechanical structure and adding a multi-channel reinforcement design. In the event of a conventional collision or bottom-hanging event, the internal battery cell will not catch fire or explode. At the same time, the battery pack has reached the IP69K standard, which is completely dustproof and can resist the impact of high-pressure and high-temperature water flow.

图片[23]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

Also thanks to the advantages of battery swapping, NIO brand owners can minimize the safety hazards of battery packs through battery swapping. Through the battery swap system, NIO can automatically eliminate old batteries with low health and high safety hazards at battery swap stations, and constantly replenish new batteries to ensure that car owners can replace batteries with both safety and performance guarantees every time.

图片[24]-NIO ET7 Chassis Structure - In-depth Analysis of the Administrative Benchmark's Hardcore Design - cnlongo

In addition, the air suspension of the NIO ET7 is standard on the whole series, providing four driving modes: comfort, energy saving, sport and sport +. According to different driving modes, not only can the suspension height and hardness be actively adjusted at all times, but also support the owner to personally select the height to achieve -10mm/0/40mm three-speed adjustment. Thanks to the intelligent electric vehicle architecture, the electronic control functions in the chassis suspension system can be upgraded online through the vehicle FOTA, allowing users to use the latest and most optimized control programs as soon as possible to continuously refresh the driving experience.

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