Exploring design concepts of polar and bipolar multicell panels manufactured with advanced joining techniques

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master_Yonamine_Mitsugui_Henrique_2025.pdf (6.47 MB)

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School of Engineering | Master's thesis
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Date

2025-05-26

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Mechanical Engineering

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Master's programme in Mechanical Engineering

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en

Pages

68

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Abstract

The combination of the Through Slot Extrusion Joining (TSEJ), created and developed at Aalto, with the Static Shoulder Friction Stir Welding (SSFSW), enables a novel fuel cell design that does not require mechanical fasteners for load bearing and gas-tight joining. With SSFSW, the Nafion, as substrate of the proton exchange membrane (PEM) is joined to PEEK, a structural polymer, providing sealing and avoiding cross-contamination between fuel/reactant. The TSEJ joins the metallic polar/bipolar plates to the structural polymer, eliminating the need of fasteners while providing enough strength to withstand high operative internal pressure, and freedom for new fuel cells design concepts. The scope of this study is the exploration of the technological opportunities enabled by the new advanced manufacturing techniques applied to fuel cell systems. The objectives are to create a tool supporting systematic design ap-proach for the multicell configurations within a panel and explore the integration of the new multicell panels in real domain applications. The systematic design approach optimizes the number and shape of cells, maximizing the operational internal pressure, considering as input the envelope/outer dimensions of a rectangular panel and having as parameters the mechanical strength of the joints and minimum acceptable side size of rectangular cells. The approach taken in this parametric optimization model can be extended to other shapes and consider the evolution of the strength as the joining techniques evolve. The integration of the new multicell panels was explored on trains, truck and buildings. In addition, preliminary experimental tests were conducted to evaluate the application of the SSFSW in joining Nafion to PEEK. The results acquired through experimental work with SSFSW showed that the process is stable, and that gastight sealing can be achieved.

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Supervisor

Vilaca, Pedro

Thesis advisor

Khadka, Prabilson

Keywords

static shoulder friction stir welding (SSFSW), proton exchange membrane (PEM), fuel cell, planar stacking of multicell panel, PEEK, Nafion

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https://urn.fi/URN:NBN:fi:aalto-202506094318

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