Author: Zhu Shiyun
Editor: Wang Lingfang
After determining their strategic direction, traditional car companies are launching an “attack” on the advantageous technological fields of emerging carmakers through cross-generational technologies.
On October 23, Mercedes-Benz China eagerly showcased the just-acquired VISION EQXX concept car to the media. This research-based conceptual vehicle, built with the goal of achieving maximum energy efficiency, has completed two real-world road tests: a 1008-kilometer journey from Sindelfingen, Germany, to Cassis, France, and a 1202-kilometer journey from Stuttgart, Germany, to Silverstone Circuit, UK, both with a single charge extending over 1000 kilometers, with average energy consumption rates of 8.7 kWh/100 km and 8.3 kWh/100 km, respectively. In other words, EQXX can travel 12 kilometers on one unit of electricity.
In Shanghai’s Expo Park 30 kilometers outside the city, the EQXX has been put to the test, with energy consumption rates of 6.7 kWh/100 km and 8.7 kWh/100 km in the eco and sport driving modes, respectively. According to engineers responsible for concept car design and testing who spoke to Electric Vehicle Observer, during media test drives in Europe, regardless of whether it was in eco mode or aggressive driving, the energy consumption performance of the EQXX remained stable at under 10 kWh/100 km. In other words, no matter what, the EQXX can travel 1000 kilometers on one charge.
More importantly, a range of 1000 kilometers on a single charge may not just be limited to concept cars. According to Sven Mueller, the Chief Technology Officer responsible for research and procurement at the Mercedes-Benz Group, “most of the innovative technologies incorporated in the VISION EQXX concept car will be applied to future mass-produced models.” He also added that “the EQXX concept car is built as a concept car for the new generation and core models of Mercedes-Benz in 2024 and 2025.”
Therefore, what will the Mercedes EQ mass-produced car look like after 18 months, and will it be able to achieve a 1000-kilometer range?
Furthermore, is the EQ, after generational changes, also regarded as a leading electric technology in China?
Mass production of CTP and replaceable battery?
Although the EQXX is a concept car, the above-mentioned engineer told “Electric Vehicle Observer” that “its battery and electric drive system are close to mass-production status.” From this, we can glimpse the core changes that the Mercedes EQ model will have after 18 months.
In terms of batteries, Mercedes EQ may leap from CTM to CTP structure, a non-module technology that integrates battery cells directly into the battery pack. This means that EQ will catch up with China’s leading companies in battery structure.
Improving battery structure has been an important direction for the development of electrification technology in recent years, from CTM to CTP, and toward the final direction of CTC, where the battery becomes part of the vehicle’s body as a chassis.
From a mass production perspective, CTP is currently the mainstream advanced technology. The BYD Blade, CATL Qilin, SAIC Magic Cube, and other products are batteries that use the CTP structure and will be mass produced and installed on vehicles from the second half of 2022.The core purpose of CTP and CTC is to simplify the structure of the battery pack to the extreme, leaving more space for the battery cells to increase the energy density of the battery pack, while also taking into account the structural strength.
In terms of energy density, the CTP battery pack used in EQXX is 200Wh/kg. In comparison, blade batteries currently have an energy density of 140Wh/kg, which will reach 180Wh/kg by 2025; the magic cube batteries have an energy density of 195Wh/kg, which can be further improved according to different battery materials; the Kirin battery is currently the highest energy density battery system, reaching 255Wh/kg, with a car endurance of more than 1000 kilometers and will be launched in 2023.
In terms of battery structure, the EQXX battery model has three pressure relief valves on one side visible, and the battery pack design has screw threads, which may achieve battery swapping as a result. Currently, the design of the magic cube batteries also includes the need for battery swapping.
It is worth noting that the overall height of the EQXX battery pack is approximately 100mm when roughly measured. In comparison, the magic cube batteries, which become thinner by using laying cells, provide height specifications of 110mm, 125mm, and 137mm respectively; the height of the SPS battery pack from Funeng Technology is between 85-145mm.
“Thinner” is also the desired element pursued by the CTP and CTC structures. A thinner battery pack can provide more Z-directional space for passengers in the vehicle without raising the floor.In addition, EQXX adopts the integrated inverter/charger (One-Box). From the current design, it can achieve DC and AC charging, with a voltage of up to 920V. It only takes 15 minutes of charging to drive 300 kilometers.
After integrating the battery pack and One-Box, the total weight of the EQXX battery is only 495 kg.
For comparison, the estimated weight of a 100 kWh battery from CATL is about 392 kg, but does not include the control system.
Like all CTP and CTC structures, the production of the EQXX battery also needs to overcome manufacturing barriers. Currently, the battery cells are packaged manually by CATL. Marco Eller, project manager of Mercedes-Benz’s battery E-Drive project, said: “Because there is currently no production line dedicated to this type of silicon anode battery.”
95% efficiency electric drive and integrated casting technology?
Perhaps the technology that is closer to mass production is the electric drive system, as well as the further upgraded integrated casting technology.
The energy conversion efficiency of the electric drive system used in EQXX can reach up to 95%, which is not only much higher than the data of 30-40% for internal combustion engine, but also higher than the average level of 80-85% for pure electric drive. The electric drive system uses a carbon fiber material for the rear axle frame, which integrates the motor and inverter together.
On the cooling side, the 180kWh motor adopts oil cooling and the inverter adopts water cooling. Moreover, the water cooling pipeline is cooled again after passing through the front of the car body and then returns to the rear axle to cool the oil. In addition, due to the use of CTP technology in the battery, the number of connection wiring harnesses is reduced, thereby reducing energy loss and the need for heat dissipation. Coupled with the 920V high-voltage platform, the overall energy efficiency ratio of 95% is achieved, and 95% energy recovery is realized.
According to a recent report by the Electric Vehicle Observer, one of the two major features of the EQXX electric drive system, compared to the commonly used electric drive systems in the industry, is the carbon fiber frame and the lower angle of the motor/inverter. This increases transmission efficiency and reduces power consumption.
Weight reduction is another focus of Mercedes-Benz in improving efficiency.
This time, Mercedes-Benz showcased an integrally cast part using bionics technology, including commonly used shock absorber covers, uncommon wipers, and large integrally cast components similar to Tesla’s rear floor.
Unlike Tesla, Mercedes-Benz has “drilled” holes in the integrally cast parts, strengthening the important stress points by studying the structural characteristics of biological bones and emptying the parts that are not related to stress structures, thus further reducing weight by 20% on the basis of integrally cast parts.It’s worth noting that from the aluminum alloy materials and production process used in the one-piece casting to the biomimetic simulation model required for “hole punching,” they are all self-developed by Mercedes-Benz. Currently, such a structure has been applied to the seat belt connection of mass-produced models.
The mass production speed of one-piece casting and biomimetics mainly depends on the speed of engineering experience accumulation. Tesla achieved a breakthrough from 0-90% in the good product rate of one-piece casting in half a year, and further improved its yield rate in the following two years. Based on a deep understanding of the casting principle in the European industrial base, Mercedes-Benz’s accumulation speed in this field can be expected.
R&D mode, producing a car in 18 months?
In addition to technology, EQXX also provides Mercedes-Benz with an opportunity to explore faster R&D modes.
As a new car with a completely redesigned appearance, interior, and power system, EQXX was produced in only 18 months, much faster than the traditional automotive industry’s R&D cycle of about four years. It is also an important capability of traditional car companies to adapt to the rapid iteration wave of electric intelligent era.
Such a fast car production is based on Mercedes-Benz’s ability to integrate various forces within the system. EQXX’s electric drive system and lightweight battery shell are jointly built by Mercedes-Benz, High-Performance Powertrains (HPP), and Mercedes Grand Prix racing team (MGP) global top racing laboratory.
On the other hand, based on a new digital development process, according to Mercedes-Benz China engineers, EQXX conducts system testing in a digitalized form, using software-in-loop. The electric drive system is tested using a test bench and onboard eMMA test vehicles. Finally, the system is integrated into a concept car test, with only 18 months spent on research and development from scratch to completion.
Xue Fengming explained the two X’s in EQXX, “The first X represents the X-factor, that is, surpassing conventional thinking about electric travel. The second X represents X-divisional, that is, strengthening the Mercedes-Benz brand through agile cross-departmental collaboration development methods. By integrating leading industry knowledge from global partner companies, start-ups, and institutions, and using highly advanced digital tools, the breadth and depth of Mercedes-Benz’s development capabilities will be enhanced.”
Competitive strategy: Energy efficiency is the key
As a research vehicle, EQXX also applied multiple leading-edge technologies to approach the energy efficiency ceiling.
The aforementioned Mercedes-Benz engineer stated that aerodynamics, active diffusers, low-rolling-resistance tires, an electric drive system with 95% efficiency, and a 12V low-voltage electronic architecture are the five core elements that enable EQXX to achieve a 1000 km range.
In automotive motion, 70% of energy is consumed to fight wind resistance. EQXX has a drag coefficient as low as 0.17cd.
However, it is worth noting that, during development, through the application of digital simulation technology, EQXX’s actual vehicle only spent 30 hours in the wind tunnel, rather than the 100 hours typically required by previous models.
Equally emphasizing practicality and aerodynamic design, EQXX features rare designs like the rearview mirror, rear seats and open-type rear wheel hub.
The rear diffuser of F1 race cars provides vehicles with better downforce and effective flow management. The active, retractable rear diffuser will automatically retract in low-speed scenarios, better adapting to the actual use scenarios of a mass-produced car.
The other significant active aerodynamics element is the active grille shutter. Due to EQXX’s efficient electric drive system and the effective heat dissipation of the aluminum chassis which results in less waste heat, the grille shutter will only open in a few edge cases dictated by the vehicle’s intelligent algorithm relying on front radar, navigation and other sensing data.
Low-voltage electronic power distribution is another innovation of EQXX. Unlike the core control functions such as driving and braking that are powered by the high-voltage platform inside the vehicle, all other electric power demands of the vehicle come from its low-voltage 12V system, including intelligent cabin features.
On the one hand, EQXX demands lower energy consumption for electronic components, such as an 8K 47.5-inch screen. On the other hand, it uses other sources of energy such as the 117 solar panels on the rear of the car, which provide 50% of the energy needed for the low-voltage system during real-world tests.
EQXX embodies Mercedes-Benz’s core competitiveness in the field of electrification: energy efficiency is real currency.
This is not just a beautiful slogan. On October 20th, the highest transaction price of battery-grade lithium carbonate was RMB 548,000/ton, and some transaction prices were lower than the cost price of lithium carbonate, which means that there is still room for an increase in the price of battery-grade lithium carbonate.
In fact, compared with the end of 2020, the price of lithium carbonate has increased by more than ten times and is still on the rise.
According to “Mr. Sydney”, a senior consultant of an Australian lithium mine, the core raw material for lithium carbonate, spodumene, may reach USD 8,000-10,000/ton by 2026, corresponding to a price of about RMB 600,000-800,000/ton for lithium carbonate, which is an additional 8.6%-31.5% increase in the cost of power batteries compared to the current level, leading to an “inflation” that is difficult for battery companies, car companies, and consumers to bear.
An insider in the lithium mining industry revealed to the “Electric Vehicle Observer” that the top two domestic battery companies have sent multiple groups of people to Africa to search for lithium mines in a low-key manner. “The person in charge of exploration has had a several-fold salary increase and has been given a deadly order: If you can’t find it, don’t come back.”
On October 21st, Mercedes-Benz also announced a 1.5 billion euro supply agreement with Canadian lithium miner Rock Tech Lithium, which will provide 10,000 tons of battery-grade lithium hydroxide over five years starting in 2026, enough to supply approximately 150,000 electric vehicles.
Save and share resources. Mercedes-Benz also hopes to find a solution to increase driving range in addition to increasing the number of batteries. EQXX is the answer.
This article is a translation by ChatGPT of a Chinese report from 42HOW. If you have any questions about it, please email bd@42how.com.