Daimler has a major involvement in the development of green powertrain technologies and hydrogen fuel cell vehicles are a key part of its strategy. Why power cars with hydrogen? Standout reasons include zero tailpipe emissions, long driving ranges and rapid refueling.
Later this year, Daimler and Mercedes-Benz are launching an innovative new vehicle based on the Mercedes-Benz GLC. The GLC F-CELL is a world’s first in at least two ways: it contains a compact fuel cell system which fits into a conventional engine compartment, and it holds a lithium-ion battery that serves as an additional energy source for the electric motor.
In a two-part interview, Prof. Dr. Christian Mohrdieck, Daimler’s Fuel Cell Director, talks to cH2ange about the new Mercedes-Benz GLC F-CELL, the benefits of hydrogen as a fuel and its essential role in sustainable low-carbon mobility. In part 1, Prof. Dr. Mohrdieck discusses the F-CELL vehicle itself, the engineering challenges involved in its development and the territories currently leading the way in hydrogen infrastructure.
The F-CELL’s engine has a power output of 150kW (204 horsepower), which is a significant power level for this type of car. It also offers an impressive driving range. This depends on driver behavior and we are waiting for confirmation of the numbers, but we expect the F-CELL to achieve a range of around 500km, based on the New European Driving Cycle.
“The power level and acceleration are the same as you’d expect from any Mercedes-Benz car, whether internal combustion engine (ICE) or hybrid.”
There are two main distinctions, the first of which concerns performance. The power level and acceleration are the same as you’d expect from any Mercedes-Benz car, whether internal combustion engine (ICE) or hybrid. It also offers the same high level of safety, quality and comfort.
The second distinction is that this car is a plug-in fuel cell hybrid, which is a first for a series production vehicle. This combination of fuel cell and plug-in battery is ideal given the progressive development of the hydrogen infrastructure. The car’s lithium battery has an energy capacity of about 9 kWh, giving the car an additional range of about 50km. It has an onboard charger so it can be charged at any socket or charging station.
Firstly, it’s a zero emissions car — no emissions at all, just water vapor coming out of the tailpipe. Secondly, the car has tremendous acceleration. This is due to the electric drivetrain that provides instantaneous torque, even at zero rpm (rotation per minute). The third feature that is very noticeable is that the car is extremely quiet, in terms of both audible noise and also vibration. It’s a smooth and very comfortable driving experience.
“We reduced the amount of platinum by 90%, which provides a significant cost reduction. Our fuel cell is not much above the platinum loading of a catalytic converter on a conventional car.”
We wanted to package the fuel cell into the same vehicle space as an ICE car, which was a major tactical challenge. This meant designing the fuel cell to very specific geometrical dimensions. An additional requirement was crash worthiness, which is not only about shape and dimensions but also the positioning of soft and rigid parts in order to achieve the desired crash behavior. As a result, we can say that this car fulfills the same very high crash standards as any other Mercedes-Benz car.
The other issue on packaging was where to situate the sizeable hydrogen cylinders. We found two very good locations. Rear wheel drive ICE cars have a driveshaft tunnel to drive the rear wheels, which isn’t necessary with an electric motor because it is mounted directly to the axle. So we put a hydrogen container into this space. Along with a second container underneath the rear seats. This enables the car to hold more than 4kg of hydrogen, which leads to the driving range that I mentioned earlier.
“A fuel cell can be refueled very quickly, in three minutes, and has a long range of around 500km or 600km. And there’s also the possibility to apply a fuel cell to a broad range of vehicles including buses, trucks and delivery vans.”
Another challenge was to insure sufficient fuel cell durability and robustness, while also decreasing costs. For example, we reduced the amount of platinum by 90%, which provides a significant cost reduction. Our fuel cell is not much above the platinum loading of a catalytic converter on a conventional car.
Was it very difficult to achieve the reduction in fuel cell size?
Yes, there were significant challenges. We needed to design a sufficient active area into a very restrictive packaging space. This was an issue on the level of electrochemical activity, and also on the mechanical engineering side. We had to find a way to package such a cell into an integrated frame that also satisfied the crash requirements. The successful achievement of this objective depended on a very close collaboration between our vehicle colleagues and fuel cell powertrain engineers.
We aim to sell our car in all areas where there is sufficient hydrogen infrastructure. The prerequisite is the presence of refueling stations within acceptable reach.
Three areas come to mind as having sufficient infrastructure at this point in time. One is Germany, our home market, where we’ve set up a joint venture, H2 Mobility, to build up and implement the hydrogen infrastructure, which is supported by the German federal government. And then there’s California, which has always been very active in this area. The state aims to have 500 hydrogen stations installed by 2022, which again involves a joint effort between car manufacturers, energy companies and the state government. The third region, where we already have more than 80 hydrogen stations, is Japan.
There are also many other countries where the hydrogen infrastructure is expanding rapidly, for example in the UK, France and some Scandinavian countries, but it takes time to build a network that provides the required coverage.
California has been very active in alternative drivetrains for many decades. It has very strict regulations regarding tailpipe emissions. For example, the state has implemented the Zero Emission Vehicle mandate, which requires large volume car manufacturers to sell a minimum number of zero emission vehicles. And there are only two options: battery electric and fuel cell vehicles. Both have specific application areas. A fuel cell can be refueled very quickly, in three minutes, and has a long range of around 500km or 600km. And there’s also the possibility to apply a fuel cell to a broad range of vehicles including buses, trucks and delivery vans. For these reasons California has been working for more than two decades to support this technology.
Similarly, in Japan, there is a close collaboration between government and car companies to support the development of hydrogen infrastructure. Japan also has one of the most dense electric charging infrastructure networks. The country has adopted a very systematic approach: it now has sufficient charging stations, so it is gradually switching government support from charging to hydrogen, because this will be the next generation technology.
In Germany we have the Clean Energy Partnership, which aims to tackle climate change by supporting the development of emission-free mobility. This is a joint initiative, established in 2002, involving car companies, infrastructure companies and government authorities. In the first phase, Linde and Daimler aimed to build 20 stations, and then six companies got together in a joint venture — Shell, OMV, Air Liquide, Linde, Total and Daimler — with the goal of building 400 stations by 2023.
Other car companies such as Toyota, Honda and BMW have joined this initiative as associated partners, creating a very broad basis for this activity. This is essential because it will take some time to build up the hydrogen network, and for the first few years this infrastructure network will not lead directly to any earnings.
This is the first part of two. In part 2, Prof. Dr. Mohrdieck discusses extending the network of hydrogen refueling stations, the development of different drivetrains and addresses issues about carbon emissions, renewable energy and the possible innovations of tomorrow. To continue reading the interview, click here.