At this year’s IAA International Motor Show in Frankfurt, Mercedes-Benz is presenting preproduction models of the new Mercedes-Benz GLC F‑CELL (earlier post). Under the technology designation EQ Power, the latest electric model (destined for subsequent series production) from the Mercedes-Benz family combines fuel-cell and battery technology in the form of a plug-in hybrid.
With 4.4 kg of hydrogen on board, the preproduction model produces enough energy for a total range of up to 437 km (271.5 miles) in the NEDC. F-CELL drivers will also benefit from a battery-powered range of up to 49 km (30.5 miles) from the 9.3 kWh (net) lithium-ion battery (13.8 kWh gross). An output of 147 kW guarantees both dynamic performance and locally zero emissions driving pleasure. In unveiling the preproduction vehicles of the Mercedes-Benz GLC F‑CELL, Daimler said it is taking another important step as part of its systematic “CASE” strategy.
Our many years of experience with fuel-cell technology pay dividends in the new GLC F-CELL: its long electric range, short refueling times and everyday practicality of an SUV will make it the perfect vehicle. This is made possible by the compact construction of our fuel-cell system. Another genuine world first is the combination with a large additional lithium-ion battery, which can be conveniently charged using plug-in technology.—Ola Källenius, Member of the Board of Management of Daimler AG, responsible for Group Research & Mercedes-Benz Cars Development
Daimler says that fuel-cell technology is a firm element of its powertrain strategy. Under the EQ product brand, the company is pooling its know-how related to intelligent electric mobility while offering a comprehensive e-mobility ecosystem of products, services, technologies and innovations. EQ is therefore a key part of the company’s strategy for the mobility of the future, known at Daimler as “CASE”. The four letters stand for the strategic future pillars of networking (Connected), autonomous driving (Autonomous), flexible use (Shared & Services) and electric drive systems (Electric), which are being systematically further developed and intelligently combined by the company. Between now and 2022, Daimler intends to bring out ten battery-electric vehicles, with the GLC F-CELL representing an important landmark.
Mercedes-Benz engineers cooperated closely with partners from the Daimler competence network to develop a completely new fuel-cell system. Compared with the B-Class F-CELL, which has been on the market since 2010 (fuel consumption: 0.97 kg H₂/100 km/CO₂ emissions, combined: 0 g/km), the overall drive system offers around 40% more output. The fuel-cell system is around 30% more compact than before; can for the first time be housed entirely in the engine compartment; and is installed on the usual mounting points like a conventional engine. Also, the use of platinum in the fuel cell has been reduced by 90%. This conserves resources while lowering the system costs with no compromises in terms of performance.
The powerful storage battery is space-savingly installed in the rear of the SUV. By means of the 7.2 kW on-board chargers, it can be conveniently charged from a standard household power socket, a wallbox or a public charging station. The charging time is around 1.5 hours if the full capacity is used.
Two carbon-fiber-encased tanks built into the vehicle floor hold around 4.4 kg of hydrogen at 700 bar. The supply of hydrogen can be replenished within just three minutes—about the same amount of time it takes to refuel a car with an internal combustion engine.
The F-CELL vehicles on show at the IAA are powered by an asynchronous machine with an output of 147 kW (200 hp) and a torque of 350 N·m. As the electric drive requires no propeller shaft, this makes room for one of the two hydrogen tanks, while the second tank is installed under the rear seat bench.
Operating strategy. Like the GLC Plug-in Hybrid, the fuel-cell variant comes with various operating modes and drive programs. The drive programs of the GLC F-CELL will include ECO, COMFORT and SPORT. ECO is optimized for low consumption. COMFORT is geared not only for comfort, but also provides ideal climate control. SPORT optimizes the hybrid powertrain for sporty performance.
While the drive programs change the behavior of the car and therefore the driving experience, the operating modes influence the interplay between fuel cell and high-voltage battery. The combination of drive programs with operating modes is presented for the first time in this form in a fuel-cell vehicle.
In HYBRID operating mode, the vehicle draws power from both energy sources. Power peaks are handled by the battery, while the fuel cell runs in the optimum efficiency range. The intelligent operating strategy means that the characteristics of both energy sources can be ideally exploited.
In F-CELL mode, the state of charge of the high-voltage battery is kept constant by the energy from the fuel cell. Driving almost exclusively on hydrogen is the ideal mode if the intention is to keep the electric range in reserve for certain driving situations.
In BATTERY mode, the GLC F-CELL runs all-electrically and is powered by the high-voltage battery. The fuel-cell system is not in operation. This is the ideal mode for short distances.
In CHARGE mode, charging the high-voltage battery has priority, for example in order to recharge the battery for the maximum overall range prior to refueling with hydrogen. This mode also creates power reserves for uphill or very dynamic driving.
In all operating modes, the system features an energy recovery function, which makes it possible to recover energy during braking or coasting and to store it in the battery.
The series-production vehicle, like the preproduction models, will be equipped with coil springs on the front axle and with single-chamber air suspension with integral automatic level control on the rear axle. This means that, even when the vehicle is carrying a load, there is no change in spring travel on the rear axle, which guarantees balanced vibration characteristics with a virtually constant natural frequency of the body, including when the vehicle is loaded.
Daimler is systematically working to prepare for series production of the Mercedes-Benz GLC F-CELL. With the current test fleet, the Mercedes-Benz engineers are taking the final key steps on the road to production start-up. Market-specific sales concepts, including a rental model, are being evaluated at present.
Like the conventionally powered GLC, this fuel cell SUV will be produced in Bremen. During development and production of the innovative fuel-cell drive, Daimler is able to call upon its global competence network. The centerpiece of the technology, the fuel-cell stack, was developed in Vancouver, Canada, together with partner Ford in the Automotive Fuel Cell Cooperation (AFCC) joint venture. Production takes place directly nearby at Mercedes-Benz Fuel Cell (MBFC).
The entire fuel-cell unit and the hydrogen storage system were developed by the Daimler subsidiary NuCellSys in Kirchheim/Nabern in Baden-Württemberg. The Daimler parent plant in Untertürkheim is responsible for fuel-cell system assembly, also in Nabern. The hydrogen tank system, consisting of carbon-fiber-encased tanks, is produced at Daimler’s Mannheim plant, while the lithium-ion battery comes from the wholly owned Daimler subsidiary ACCUMOTIVE in Kamenz, Saxony.