Modernizing submarine construction with 3D printed fuel cell components
Combining 3D printing and fuel cell technology is modernizing submarine construction. Stefan Krummrich, Chief Engineer Fuel cell / AIP Systems and Karsten Green, Senior Systems Engineer at the TechCenter Additive Manufacturing from thyssenkrupp Marine Systems, explain how and why – and give an outlook on other areas where 3D printing could bring advantages in naval shipbuilding at thyssenkrupp Marine Systems.
Why use fuel cells in submarines?
In order to understand, why using 3D printing or Additive Manufacturing in fuel cell technology is an innovation one has to understand why fuel cells are used in submarines in the first place. “The research and development of fuel cells for submarines has been an integral part of thyssenkrupp Marine Systems’ expertise since the 1980s and today we are world market leader in the supply of fuel cell technology for submarines”, explains Stefan Krummrich, Chief Engineer Fuel Cell / AIP Systems at thyssenkrupp Marine Systems.
Submarine propulsion must be independent of air when it is submerged. And since submarines stay underwater for quite a while, the power source must also be able to supply energy over a long period of time. “Since fuel cells generate energy from hydrogen and oxygen, which can both be stored on board, they are the optimal way to supply submarines with energy underwater”, says Stefan Krummrich.
Before fuel cells became the go-to energy solution for submarines in early 2000, submarines had to surface frequently to recharge the lead acid batteries with the diesel generators onboard. This limited submarines to diving times of only a couple of days maximum. Today, submarines equipped with fuel cells can stay underwater for several weeks – a huge improvement in performance and key to performing a larger variety of tasks underwater.
"The submerged time is still limited, but time runs out much later for the crew and the submarine's power supply," Krummrich says. If a submarine must remain submerged for an extended period during combat and cannot surface without risk, this time advantage can be crucial to the crew's survival.
3D printing, also known as additive manufacturing, makes it possible to produce parts in one piece, even in the most complicated geometric shapes. This 3D printed object demonstrates the level of detail 3D printing makes possible.
How 3D printing improves fuel cell construction
Increased diving time is the key advantages of fuel cell use in submarines. But what are the advantages of using Additive Manufacturing in fuel cell construction? “There are two main factors”, explains Karsten Green, Senior Systems Engineer at the thyssenkrupp Marine Systems TechCenter for Additive Manufacturing: "One is to increase efficiency in limited installation space, and the other is to increase system availability and safety."
Space on board of a submarine is a limited resource. Components built for submarines therefore must be particularly space efficient. 3D printing enables our experts at thyssenkrupp Marine Systems to produce highly complex components that are robust at the same time. "3D printing allows components to be manufactured from a single piece. Installation space for seals can be significantly reduced and required installation space for the assembly of individual components can be saved. The space thus saved can serve to increase the performance of the fuel cell," explains Karsten Green. In this way, 3D-printed components increase the performance of the fuel cell system.
An important consideration in submarine construction is to take up as little space as possible. Additive manufacturing makes it possible to install the individual components in a space-saving manner.
Additionally, robustness and sealing against leakage are important safety factors for components used in fuel cell technology, as fuel cells are often powered with explosive gases such as hydrogen. "3D printing technology offers the best conditions for this. 3D printing technology allows weak points such as weld seams or seals to be reduced, this increases system availability," explains Karsten Green. Additionally, 3D printing technology has evolved enormously in recent years. “While the technology used to be limited to hard plastics, it can now also process various metals that can withstand different pressures and temperatures”, says the Senior Systems Engineer.
3D printed fuel cells – a promising collaboration
More than anything, however, what makes additive manufacturing from thyssenkrupp Marine Systems' TechCenter unique is the close cooperation with other departments, all under one roof. The TechCenter Additive Manufacturing at thyssenkrupp Marine Systems works closely with colleagues from fuel cell production to release synergies within the company. The fact that the 3D printing department is not external but an integral part of thyssenkrupp Marine Systems itself ensures a very practical and efficient design of components.
“This constellation is unique on the market for fuel cell technology for submarines”, says Karsten Green, Senior Systems Engineer at the TechCenter Additive Manufacturing at thyssenkrupp Marine Systems. “Communicating shorthanded and being able to deliver state-of-the-art fuel cell and 3D printing technology from one single source gives us at thyssenkrupp Marine Systems an advance, which is unparalleled by competitors worldwide.”
A promising outlook into the future and it doesn’t stop there. The two departments plan to continue working together in the future.
Plans for the future
„Our plans for the future definitely include expanding both areas of expertise inhouse – fuel cell technology and construction as well as Additive Manufacturing”, says Krummrich. The future of 3D printing is producing entire assemblies instead of single parts only – as it is still the case. It is also of interest to find out in which areas of construction and production at thyssenkrupp Marine Systems Additive Manufacturing can be implemented further. “In order to identify such potential, we have to inform our colleagues about the work we do and what our inhouse 3D printing department has to offer and have a dialogue with colleagues from various departments and areas of expertise”, Green states. The Additive Manufacturing department of thyssenkrupp Marine Systems already offers seminars to inform colleagues of the possibilities and different uses of 3D printing, today. “Together with our colleagues, we can identify such potential and develop the processes to implement Additive Manufacturing effectively into existing process chains.”, explains Stefan Krummrich.
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