Manufacturer-independent fuel cell stack: an innovative development platform for industry and science

With the manufacturer-independent fuel cell stack, the Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Würtemberg (ZSW) Ulm has taken an important step towards a broader application of fuel cell technology.

For the first time, a generic fuel cell stack is available on the market, which opens up opportunities for companies - including SMEs - to participate actively in this promising technology and help transform the energy system..

The development of a manufacturer-independent fuel cell stack has the potential to transform the industry for the long term. The ready-to-use fuel cell stack gives companies easy access to fuel cell technology - from now on, the industry can decisively drive innovations in this field in cooperation with ZSW Ulm


Dr. Joachim Scholta
+49 731 9530-206
CAD rendering of the generic stack, including compression unit and media connections

Generic fuel cell stack: A Manufacturer-Independent Development Platform

In cooperation with EKPO as industrial partner, ZSW Ulm has realized a manufacturer-independent fuel cell stack as an open development platform.

Size, design and power density correspond to the fuel cell systems currently used in the automotive sector. The specifications were developed in a preliminary project with the automotive and supplier industry.

The stack is designed for a power output of up to 150 kW.

By providing a manufacturer-independent fuel cell stack as an open development platform, the supplier industry will have easier access to the technology. It will allow companies to enter the growing fuel cell market without undertaking extensive development work themselves.

"The 'generic fuel cell stack' creates a kind of universal tool for the technological development of fuel cells. In addition, we can then also provide SMEs with components or entire fuel cells for their own product development," says Prof. Dr. Markus Hölzle, member of the ZSW board of directors and head of the Electrochemical Energy Technologies division in Ulm.

The functional sample will be available for research projects in mid-2023 and provide companies with access to the industry.

If we have aroused your interest, please feel free to contact us:



Dipl.-Ing. (FH) Frank Häußler
+49 731 95 30-791

Fuel Cell Stacks: Key Technology for Energy Transition

Fuel cell stacks are a core component of fuel cell technology and are considered a key technology for the energy transition. They consist of several fuel cells connected in series to provide the required power. Fuel cells generate electricity and heat by converting hydrogen and oxygen into water. The process produces no harmful emissions like carbon dioxide (CO2).

The importance of fuel cell stacks in the energy transition is reflected in their wide range of applications. They can be used in various sectors to meet energy needs in an environmentally friendly way. In the transportation sector, for example, fuel cell vehicles offer a promising solution for emission-free mobility. In industry, they can be used for decentralized power generation and emergency power supply, and in building technology for heat and power supply.

The promotion and further development of fuel cell stacks is therefore of great importance for the success of the energy revolution. ZSW's manufacturer-independent fuel cell stack makes the technology more accessible to companies, which can accelerate innovation and promote the spread of fuel cell solutions.

A single cell of a fuel cell stack consists of two bipolar plates and the membrane electrode unit (in the middle) © CAD-Construction ZSW.

What is a fuel cell stack?

A fuel cell stack is the heart of a fuel cell system and consists of several individual fuel cells stacked which are stacked on one another and electrically connected in series.

Function of a Fuel Cell Stack: A fuel cell stack's function is to convert chemical energy directly into electrical energy by reacting hydrogen and oxygen in an electrochemical reaction into water. This process does not produce any harmful emissions, only heat and water vapor as by-products.

Fuel Cell Stack Applications: Fuel cell stacks are used in a wide variety of applications. They can be used in various sectors such as transportation, industry or buildings.

In vehicles, especially cars and buses, fuel cell stacks are used as an environmentally friendly propulsion solution that enables zero-emission mobility. In industry, fuel cell stacks are used in stationary energy systems for distributed power generation and emergency power supply. In the building sector, they are used for efficient heat and power supply, for example in combined heat and power plants or as part of micro power plants.

CAD design of the generic fuel cell stack consisting of 500 single cells with metallic bipolar plates. © ZSW

Development and construction of fuel cell stacks at ZSW in Ulm

The development and construction of fuel cell stacks is a complex process involving various materials, technologies and manufacturing techniques.

For more than 30 years, ZSW has been involved in the development and construction of innovative fuel cell stacks, including polymer electrolyte membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) in the power range from a few watts to 100 kW for all applications.

The main focus of ZSW is the transfer of scientific-technical knowledge into practical applications.

The goals are the optimization of performance, lifetime, efficiency and compactness of fuel cells in accordance with the specific requirements of the application and field of use.

Quality assurance and quantity-adapted automation of stack assembly play an important role.

Early on, the ZSW took up the topics of quality assurance and quantity-adapted automation of stack assembly and tested them successfully on its own stack designs. As part of this work, extensive know-how was built up on the automated handling of components, the application of seals, and the assembly and stacking of cells.

Further work is focused on manufacturing technology and characterization of PEM fuel cells, components and stacks. This includes optimizing materials and membranes, improving electrode structure, and developing more efficient catalysts. Through this continuous research and development, ZSW contributes to the advancement of fuel cell technology and makes it available for a wider range of applications in industry and everyday life.

Fuel Cell Stack Design

The design of a fuel cell stack is complex and consists of several main components, each performing specific functions.

At ZSW, numerous application-specific designs are developed, which differ in terms of active area per cell, bipolar plate concept, pressure drop and operating temperature range.

The stacks are characterized by high specific power as well as safe and reliable operation in the intended wide operating ranges. Versions with active areas ranging from 50 to 560 cm² are available and can be customized to meet specific customer requirements.

ZSW-BZ-Stack-100 © ZSW
CAD exploded view of the generic fuel cell stack. © ZSW

For example, the manufacturer-independent “generic stack” is designed for a maximum power of 150 kilowatts, which requires 500 individual cells, each with two metal bipolar plates. The advantage of metal bipolar plates is that they can be manufactured by forming, which allows high volumes with short cycle times. Here, the challenge lies in the very thin wall thicknesses of only one-tenth of a millimeter at a length of more than 40 centimeters per sheet.

Bipolar plates are crucial components of a fuel cell. They ensure that hydrogen and atmospheric oxygen are evenly distributed on the two external sides (cathode and anode), while the cooling water is conducted via the inner side of the plates. Highly filigree channel and web geometries as well as a manifold and sealing concept are used to achieve this. Computational fluid dynamics (CFD) is used to simulate and optimize these structures..

In the project for the development of the manufacturer-independent fuel cell stack, all relevant parts of the cell design such as port channel geometry, active area and manifold area were investigated by means of appropriate CFD simulations using ANSYS Fluent®.

The simulations were performed equally for the air, hydrogen and cooling sides. The operating boundary conditions from the EU-funded AutoStackCore project form the basis. A balance-of-stack concept was developed for the bipolar plates. This includes the current collectors, the compression plates, a tensioning unit realized by metal strips and disc springs as length compensating units, as well as the end plates including the media supply systems. For the connection to the test bench, a connection device has been developed. It allows the stacks to be connected and disconnected quickly and easily.

For existing designs as well as for designs developed at ZSW, prototypes can be manufactured and tested at the customer's request.

An overview of the prototypes available at ZSW is available as a PDF file: Download: Brennstoffzellen Stacks Prototypen

CAD view of the generic stack, including grouting unit and media connections

Potentials and advantages of the generic fuel cell stack

The generic fuel cell stack developed by ZSW in cooperation with EKPO as industrial partner offers a variety of advantages and opportunities for the industry in Germany and worldwide. Such a manufacturer-independent fuel cell stack serves as a universal tool for the further technological development of fuel cells and gives interested companies access to components or complete fuel cells for their own product development.

By using the generic fuel cell stack, companies can save significant development costs and resources. They do not need to develop their own stack. The time to market for new fuel cell systems can be significantly reduced. This also minimizes the risk for companies entering a new market, since access to the technology is already guaranteed by the fuel cell stack developed by ZSW and EKPO.

The industrialization of fuel cells is crucial to bring them to market in large quantities at low cost. To advance the industrialization of fuel cell stacks, the ZSW in Ulm is working with other partners on HyFaB. The HyFaB model factory is intended to pave the way for the large-scale production of fuel cells.

Overall, the manufacturer-independent fuel cell stack at ZSW Ulm offers significant advantages for the industry:

  • Easy access to fuel cell technology
  • Reduced costs and resources for R&D
  • Reduced risk due to the long-term know-how of the scientists and engineers at ZSW Ulm
  • Accelerated time to market for new fuel cell systems

Quality assurance and test procedures for fuel cell stacks at the ZSW in Ulm

The Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW) in Ulm has more than 20 years of experience in testing fuel cells and relies on comprehensive quality assurance and test procedures. These procedures are critical to ensuring the high performance, durability and reliability of fuel cell stacks that are so important to the industry.

The quality assurance and testing technology at ZSW includes fully automated test benches for fuel cells and fuel cell stacks. These test benches enable researchers to precisely analyze the performance, lifetime and efficiency of the stacks developed and to identify optimization potential. Through these tests and the continuous improvement of the stack designs, the specific requirements of the various application areas can be met.

View into the new test center at HyFaB

The lifetime of a fuel cell stack is a critical factor for the industry as it influences the economics and reliability of the systems deployed. The quality assurance and testing procedures applied at ZSW help to maximize the lifetime of fuel cell stacks and thus increase the economic viability and attractiveness of the technology for industrial applications.

Fuel Cell Systems

Fuel cell systems are complex units consisting of different components and can be used in a wide range of applications and power classes. ZSW has 20 years of experience in designing and building fuel cell systems for various applications.

A fuel cell system consists of several main components: the fuel cell stack, which serves as the heart of the system and enables the chemical process to generate electricity, and additional components such as control, monitoring, hybridization with batteries, and DC/AC converters. These additional components are necessary to operate the system efficiently, safely and reliably.

ZSW offers systems ranging from a few watts to 50 kW and supports customers in planning, simulation-based design, system prototyping, and system characterization and qualification. In addition, ZSW is involved in the testing and qualification of system components such as air supply, catalytic burners, heat exchangers and sensors.

The periphery for a fuel cell system for vehicle use consists of a system of components such as compressors, heat exchangers and pressure control valves. The picture shows an exemplary laboratory setup.

The integration of fuel cell stacks into fuel cell systems is a critical step to ensure optimal performance and efficiency. It is important that the fuel cell stack is optimally matched to the system components to achieve the best possible performance, lifetime and efficiency.

For the development and construction of fuel cell systems, ZSW offers

  • Complete systems
  • System design and prototypes
  • Testing and qualification of system components
  • Safety evaluations
  • Packaging studies
  • Product certification support


Dr. Alexander Kabza
+49 731 9530-832

We ensure that the fuel cell systems we develop meet industry requirements and applicable standards. Click here for more information: Fuel Cell Systems: Design and Engineering

Fuel cell system for buses. Bild: ZSW/ECS

In contrast to the battery system, the fuel cell system requires its own peripherals to supply media to the stack. For vehicle use, a system of components such as compressors, heat exchangers, and pressure control valves is needed to set the operating conditions appropriate for the particular operating point. Some developments in the field of internal combustion engines can be transferred to fuel cell systems. However, the drive technologies are in some cases very different in terms of the requirements placed on the components. The performance characteristics of the peripherals have a significant impact on the efficiency and lifetime of the overall system.

Task of the ZSW is to support the industry in the disruptive context of fuel cell technology in terms of definition, verification and validation of the requirements for new components. Using the in-house developed system test bench, components of different performance classes can be flexibly integrated and tested. The agile test environment enables fast and individual adaptation of the software and hardware configuration to a wide range of interfaces and operating parameters. Collected test data also flows anonymously into the development of the company's own advanced system models. As part of a scientific work, existing implementations of open-source models are being further developed in order to optimize the design and operating strategies of fuel cell systems for a wide range of applications in the future.

HyFaB - Model Factory for Large-Scale Production of Fuel Cell Stacks

The HyFaB project aims to advance the industrial production of fuel cell stacks for vehicles. The objective is to develop automated manufacturing and quality assurance processes, factory acceptance testing and commissioning of fuel cell stacks.

HyFaB is designed as an open industrial platform in which partners from the automotive and fuel cell supplier industry as well as from the mechanical and plant engineering industry, in particular small and medium-sized enterprises (SMEs), can participate.

In addition to the ZSW, the Fraunhofer ISE in Freiburg and the German Engineering Federation (VDMA) are involved in the HyFaB project.

In the new HyFaB building, industrial production of fuel cell stacks for vehicles is being driven forward.

Manufacturer-independent fuel cell stacks, such as those developed by ZSW Ulm and EKPO and further developed in the HyFaB project, offer enormous opportunities for industry and the energy revolution. This development platform enables companies, especially SMEs, to save resources and costs.

The HyFaB model factory makes a significant contribution to accelerating the mass production of fuel cell stacks and promoting the market launch of fuel cell systems for the automotive industry. The collaboration between academia and industry enables innovative technologies to be developed and tested in practice, which is crucial for the future of sustainable mobility.

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