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July 15, 2022

Innovative fuel cell technology

The German Federal Ministry for Digital and Transport supports a consortium led by MANN+HUMMEL in developing an innovative sensor array.

MANN+HUMMEL cathode air cleaner system for commercial vehicles

Ludwigsburg, July 2022 – The shift taking place in the world of transport means that we are currently seeing different drive systems competing to replace the combustion engine. The key criteria here are performance, operating time, sustainability and, last but not least, cost. While industry and politics are concentrating mainly on battery-powered electric vehicles when it comes to individual mobility, there is an increasing focus on the use of fuel cells for commercial vehicles. Innovative air filter sensor technology from MANN+HUMMEL promises to improve the performance/lifetime ratio here and the company has its sights set on the Chinese market in particular.

The ISAAC project (for the development of a sensor array for cathode air cleaner systems that absorb harmful gases as part of a German and Chinese partnership) is receiving EUR 840,412 in funding from the German Federal Ministry for Digital and Transport under the National Innovation Programme for Hydrogen and Fuel Cell Technology. The funding guideline is being coordinated by NOW GmbH and administered by Project Management Jülich (PtJ).

Problem: contaminants in cathode air

“The lifetime of a PEM fuel cell is affected by conditions such as the cleanliness of the cathode air in the catalyst,” explains Dr Michael Harenbrock, Principal Expert Electric Mobility at MANN+HUMMEL. “Oxygen is reduced in the platinum-coated cathode but gases containing nitrogen or sulphur bond to the platinum particles. This causes to them block the catalyst, which impairs the performance of the fuel cell.”

Activated carbon filters specifically adapted to these types of harmful gases offer effective protection as they selectively absorb them but they only have limited storage capacity. “We do not yet have empirical values for the recommended time intervals for filter changes in fuel cells to the same extent as we are used to with combustion engines as the technology is still extremely new,” says Harenbrock. “It therefore remains difficult to predict the lifetime of a filter while we still do not know the quantity of harmful gases that the filter will have to contend with in real-life operation. Field trials in Germany have shown that this is heavily dependent on the traffic environment in which the vehicle is being driven.”

Filter saturation: sensor array indicates when maintenance is required

In order to facilitate usage-based maintenance, MANN+HUMMEL is currently working with two other partners as part of a consortium to develop a sensor array for the cathode path. This will indicate when the activated carbon used has become saturated and harmful gases are beginning to penetrate the filter. As part of this project, the Duisburg-based Institute for Energy and Environmental Technology (IUTA) is developing a penetration sensor array based on gas-sensitive surfaces for use in automobiles in changing environmental conditions and a smart signal processing system adapted to this. The sensor layers, which will react sensitively and selectively to selected harmful gases and mixtures of harmful gases, are being supplied by the Research Institute for Precious Metals and Metal Chemistry (fem Forschungsinstitut Edelmetalle + Metallchemie) in the German town of Schwäbisch Gmünd. “In addition to developing cathode air cleaner media specifically adapted to the profiles of harmful gases, at MANN+HUMMEL we are focusing on integrating the array into the cathode air path,” says Harenbrock. “At the end of this process, we will have a prototype, which will need to be made ready for series production.”

It is envisaged that this new development will mainly be used in fuel cell systems for commercial vehicles. “The lifetime requirements are much higher for commercial vehicles than in the passenger car sector,” explains Harenbrock. “As this type of drive technology has to compete with combustion engines, the overall costs need to be financially viable. The sensor measuring technology required here, which is already capable of reliably identifying very low concentrations of gases, is currently mainly used in test benches. It is too expensive to use in vehicles. The aim of our project is to reduce the costs for the sensors while simultaneously increasing the fuel cell lifetime, i.e. to enable consistent performance for as long as possible through predictive maintenance, i.e. by changing the filter at the right point.” 

Making hydrogen a priority: focus on the Chinese market

The intention is that the state funding will help to make hydrogen and fuel cell technology competitive within the transport sector, thereby bolstering the domestic economy. It is therefore particularly important that this work is closely linked with a sister project in China that is being supported by the Chinese Ministry of Science and Technology (MoST). The partners on the Chinese side are Tongji University in Shanghai, MANN+HUMMEL China and an OEM partner for field trials. Harenbrock says: “The differences in air quality mean that, in order to design the filter elements, we first need the relevant data from China. Finally, the prototype we have developed will be tested locally in China. The Chinese sales market is extremely interesting as there is currently a lot of support there for expanding the hydrogen strategy in the commercial vehicles sector.”

You can find further information about the National Innovation Programme for Hydrogen and Fuel Cell Technology Phase II (NIP 2) at:



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