Annual Report 2020

Cell culture

Fuel cell drives will be a vital technology on the road to zero-emissions mobility. MAHLE has pooled its activities in this field since 2020 and believes it has great potential, particularly for commercial vehicles. By working with an innovative fuel cell developer, MAHLE wants to help the drive of the future make a breakthrough.
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Philipp Sommer is a passionate car fanatic with a weakness for complex systems developments and “gasoline in his blood,” as he puts it, smiling. However, he is currently working on ways of using hydrogen to power large commercial vehicles. The young mechanical engineer heads the fuel cell project house at MAHLE. This is where the company brought together all its activities relating to this future technology in 2020 with the aim of boosting its ability to penetrate the market. “We want to think outside our own system boundaries and pursue ambitious targets, particularly in terms of the costs and performance of our components,” explains Sommer.

To turn this pooled knowledge into technical reality, Sommer and his team are able to take advantage of the brand-new test bench at the plant in Stuttgart / Germany. This is where they carry out intensive testing on new developments in the periphery of the fuel cell within a complete drive system. In a nut shell: They improve air management, thermal management (i.e. heating and cooling) and power electronics. As a result: Fuel cells should be significantly cheaper while also durable and thus suitable for mass production. After all, fuel cell technology is regarded as a promising means of achieving the global goal of zero-emissions mobility. As Sommer adds: “Through our work, we’re securing MAHLE a share of a market that’s experiencing sustained growth.” MAHLE is already active in this highly promising market with components for both passenger cars and commercial vehicles. For example, it has been a supplier for series production applications in fuel cells on behalf of many well-known international manufacturers for over a decade. Even now, the fuel cell experts are working on customer projects for future generations of fuel cell-driven passenger cars and commercial vehicles.

New testing infrastructure
With the installation of hydrogen testing infrastructure in Stuttgart, MAHLE has strengthened its position as a development partner for all aspects of the fuel cell and combustion engine. MAHLE’s focus is on the system peripherals surrounding the stack itself. Fuel cell systems can be tested and further developed on several test rigs in the new facility. This also gives MAHLE experts the opportunity to gather key data for fundamental development work on fuel cell technology.

Technology with a tailwind

With these efforts, MAHLE has moved into the fast lane with respect to a development for which, in Dr. Marco Warth’s opinion, it is worth picking up the pace: “The big difference from the situation maybe five years ago is that public institutions around the world are now putting a tremendous amount of funding into fuel cell technology.” Warth has a degree in mechanical engineering and a doctorate in technical sciences. At MAHLE, he is responsible for development activities in the field of mechatronics under the umbrella of ­Corporate Research and Advanced Engineering. In his words, that means “everything that we don’t have in the MAHLE product portfolio yet.” And his job? “To turn good ideas into a product within five years.”

Dr. Marco Warth
The big difference from the situation maybe five years ago is that public institutions around the world are now putting a tremendous amount of funding into fuel cell technology.
Dr. Marco Warth,
Director Corporate Advanced Engineering, MAHLE, Stuttgart/Germany

Warth is confident that this will happen with fuel cells, especially given the political tailwind. In Germany, for example, the Federal Ministry for Economic Affairs and Energy (BMWi) published a National Hydrogen Strategy in June 2020 with plans to invest more than EUR 300 million by 2023. The European Commission has put forward a European Hydrogen Strategy, the primary goal of which is to make investments in hydrogen infrastructure that spans member states, such as in decarbonizing the production of hydrogen by using alternative energy sources. In its Action Plan for an Energy Technology Revolution, China plans to achieve an annual production capacity of 5.5 million fuel cell systems and construct 10,000 hydrogen refueling stations by 2050.

Clear sector focus

Marco Warth calls these “positive signals,” which are stirring ambitions at MAHLE—and raising questions: Which components will we concentrate on? For which sales markets? Where will they be produced? The team in the fuel cell project house quickly agreed on the sector that is best suited to using hydrogen as a means of energy storage. “It’s the commercial vehicle sector. It accounts for a considerable share of the CO2 emissions from traffic and, as journeys in this sector are usually long and often international, it would appear to be somewhat less suitable for battery or hybrid solutions,” says Warth. Fuel cell technology offers a long cruising range, rapid refueling, and route flexibility—without impairing the payload capacity.

To see that the team have not come to the wrong conclusion, you only have to take a look at the example of the port of Hamburg in northern Germany. One of the world’s largest facilities for the climate-neutral production of so-called green hydrogen is scheduled to go into operation here by 2025. Compared with gray hydrogen, which is obtained from fossil-based natural gas, green hydrogen is made by splitting water into hydrogen and oxygen. When this is done using renewable electricity—generated by offshore wind farms, for example—the result is an almost emission-free energy carrier. And in Hamburg, the aim is that this will be used to fuel as many as possible of the around 15,000 trucks that call at the port every day.

MAHLE believes that the greatest potential currently lies in the European market. “We want to produce in Europe for Europe,” says Warth. China, which intends to have a climate-neutral economy by 2060, is another exciting market—as is North America. The new US administration under Joe Biden has identified hydrogen as one of five priorities in its innovation strategy. By 2050, the country aims to be climate-neutral and to become the world’s number one producer of the energy carrier.

The peripherals are key

It takes more than just a fuel cell to turn ordinary external air and hydrogen into the electricity that drives a commercial vehicle. Many things in a drive system need to be managed, from temperatures, pressures, and voltages to undesirable suspended particles. MAHLE has solutions to deal with all of this. The illustration shows what is needed to ensure a functioning drive.


Thermal management

The large front-end cooling modules are just the start. The cooling system—composed of heat exchangers, electric pumps, valves, and fans from MAHLE—runs through the entire vehicle, much like the human circulatory system.


Filters like those from MAHLE block harmful gases and particles, which could damage the cell or shorten its service life.

Electric compressor

This is where the supplied air is compressed. Because even small quantities of oil can cause irreversible damage to fuel cells, MAHLE is developing oil-free bearings.

Charge air cooler

Compression heats the air, which must then be cooled ­efficiently ahead of cold combustion in the cells.


Fuel cells must be kept reliably moist. Humidifiers from MAHLE transfer humidity from the exhaust air to the dry supply air.

MAHLE fuel cell monitor

The module monitors the signals from the fuel cell stack and provides feedback to the central control unit.

DC/DC converter

A DC / DC converter is a highly efficient link between the stack and the battery or between the battery and the 12-volt low-voltage grid.

Exhaust air system

The plastic exhaust air pathway optimized by MAHLE for the entire system is much lighter than metal designs, runs more quietly, and retains maximum design freedom.

Hydrogen storage tanks

Hydrogen is stored at an extremely high pressure of 700 bar. Because it remains gaseous, the tanks are subject to very strict safety standards.

Intercontinental teamwork

In view of these multinational efforts, Marco Warth believes that fuel cell systems will become global products that will, at most, differ at a local level in terms of the corresponding infrastructure. As for customers, he thinks MAHLE will focus on the OEMs. But Warth also stresses that the company continues to stand by its open attitude toward all technologies: “We’re not interested in ideology. Instead, we want the optimal powertrain solution for each sector.”

We’re not interested in ideology. Instead, we want the optimal powertrain solution for each sector.
Dr. Marco Warth,
Director Corporate Advanced Engineering, MAHLE, Stuttgart/Germany

In 2020, MAHLE made a major leap forward in terms of the ongoing development of its expertise and portfolio relating to fuel cells when the technology group agreed to collaborate with the Canadian fuel cell manufacturer Ballard Power Systems Inc. The North American company is regarded as a high-end fuel cell company. Ballard’s products stand out when it comes to parameters like durability and are primarily developed for use in trucks, buses, ships, and railroad applications, where they offer great potential.

Through this technical cooperation, MAHLE is accelerating the broadening of its competences in the priority areas of air management (particularly filtration and humidification), thermal management, and power electronics as well as gaining access to expertise in what is known as the stack. This is where the actual cells in which hydrogen and oxygen react to form water and thereby generate electricity are literally stacked together. This knowledge will also help MAHLE to further expand its portfolio of products in the periphery of the stack in order to develop even more cost-effective and robust products for new and existing MAHLE customers in the future.

“The cooperation is both a huge opportunity and a genuine challenge. After all, a Canadian technology specialist and a German automotive supplier have two very different mentalities. These cultures and the 8,000-kilometer distance have to be bridged, and sometimes there’s a need to intentionally introduce new approaches as well. Development then progresses somewhat faster than we would have thought possible,” says Sommer.

Philipp Sommer
Through our work, we’re securing MAHLE a share of a market that’s experiencing sustained growth.
Philipp Sommer,
head of the fuel cell project house at MAHLE

One thing is certain: no one develops a new technology alone, especially one as complex as a fuel cell drive. “Both companies need to collaborate to make advances quickly,” says Marco Warth. After all, the fact that the technology works was proven long ago. It is now a matter of establishing how it can be produced at an industrial scale and at reasonable cost. This is where MAHLE’s many decades of experience in the automotive industry come in. “We understand the sectors, can handle all the specifications, and are well positioned in all the sales channels,” emphasizes Warth. As for Ballard, the engineer is impressed by the typical North American drive to put ideas into practice: “Their experts take an extremely pragmatic approach to their research, whereas we work in a very goal-­oriented and systematic way, with development time frames of several years.”

24 %

Globally, 24 percent of global energy-related CO2 emissions are attributable to the transportation sector, which also includes passenger car traffic. Road freight is responsible for one third of this amount. Fuel cell technology is seen as a solution for the emission reduction.

Source: International Energy Agency (IEA), 2018

A system mindset

MAHLE’s clear role in the partnership is to concentrate on developing the individual components of a fuel cell system—but it also needs to consider the bigger picture: “It’s a very complex task,” explains Philipp Sommer. “The design criteria for the components change as soon as I shift my focus from the individual parts to the system.” We can see an example of this in various components, such as humidifiers, that have air and hydrogen flowing through them. “Although a circular cross section at component level theoretically achieves the best results in terms of pressure losses and efficiency, we now tend toward more elongated, rectangular designs, because they can be integrated much more effectively into the overall system and have cost advantages when it comes to manufacturing.” In making these adjustments, MAHLE puts the know-how in the field of filtration and plastics processing that it has built up over decades to good use.

“Given the current state of the art, a fuel cell drive is not a stand-alone piece of technology—instead, it’s always engineered together with a battery. The question is: What power output and design will it have?” explains Warth. He also comments that suppliers like MAHLE will need to have an input into these matters at an even earlier stage in the future. “I expect the spectrum of vehicles to broaden still further. The days of one model for all applications are over. This increasing diversification will also have an impact on our components.”

The goal: proud faces

Marco Warth imagines that it will only be a few years until an efficient hydrogen infrastructure and trucks with fuel cell systems that are able to compete on price and performance are available. “Until then, we’re advancing from milestone to milestone. All with the goal of seeing the proud faces of our colleagues when we help the fuel cell drive in which our components are installed to achieve its major breakthrough,” says Marco Warth, adding that this moment is what motivates him every day. And maybe then, Philipp Sommer will declare that he now has hydrogen rather than gasoline in his blood.

3 questions for ...

Randy MacEwen, CEO at Ballard Power Systems Inc.,
on strategic objectives and the technical collaboration with MAHLE.

Randy MacEwen
Our objective is to bring to market the best fuel cell engines for medium- and heavy-duty commercial vehicles.
What made Ballard decide to cooperate with MAHLE?

There is a growing demand for fuel cell engine solutions for commercial vehicles. Ballard has been developing this technology for the past 40 years. We realized that we needed a reputable partner with strong expertise in developing and producing drive components and systems to succeed in the industrialization stage. As a global Tier 1 supplier to the automotive industry, MAHLE brings unique expertise in developing components for fuel cell systems and in-depth knowledge of truck system requirements.
What are Ballard’s strategic goals, and how does the partnership with MAHLE contribute to these?

Our objective is to bring to market the best fuel cell engines for medium and heavy-duty commercial vehicles. MAHLE’s key contributions will include systems integration knowledge—such as in cooling and power electronics—and fuel cell-specific components, like filters and DC/DC converters. Added this is the company’s expertise in development optimization—from modeling to testing and manufacturing scale-up capabilities on five continents.
How is the cooperation going in these challenging times with respect to the pandemic?

Despite COVID-19, our cooperation made significant progress in 2020. Our teams have been able to develop a program plan and define targets and product requirements. Working in these challenging conditions has brought our teams closer together and validates our alignment on shared values, corporate culture, and a vision for sustainable technology.