The fabrication of high-aspect-ratio micro-flow channels on metallic bipolar plates using die-sinking micro-electrical discharge machining

Hung, Jung-Chung; Chang, Dyi-Huey; Chuang, Yin

doi:10.1016/j.jpowsour.2011.09.065

Cited by 55 publications

(16 citation statements)

References 20 publications

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“…However, the drawback is that the performance of the bipolar plate will be reduced [5]. Meanwhile, according to Figure 2, the V shape is more suitable [18]. The other important factor that needs to be considered is the geometry of difference shape must have with same area, as shown in Figure 3.…”

Section: Serpentine Type Flow Channelmentioning

confidence: 99%

Fabrication of a flow channel for the production of polymer composite bipolar plates through hot compression molding

et al. 2017

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Materials used to fabricate polymer electrolyte membrane fuel cell (PEMFC) bipolar plates need to be light, strong, cheap, easily fabricated, mechanically stable, and have low surface contact resistance. Additionally, the performance of PEMFCs is greatly influenced by the materials used, flow channel design and shape to be fabricated on the bipolar plate surface. In this study, the fabrication of a flow channel through the hot compression molding method was developed. All materials used were in powder form, with graphite (G), carbon black (CB) and ferum (Fe) as fillers, and polypropylene (PP) acting as binder. The ratio of fillers (G/CB/Fe) to binder (PP) was fixed at 80:20. The fillers ratio was fixed in the range of (25 to 65 wt%) G, (10 to 30 wt%) CB and (5 to 25 wt%) Fe, and all fillers were mixed using a ball mill machine. The second stage of the mixing process involves the mixing of fillers and a binder, which was mixed using a internal mixer machine. Subsequently, the compaction process through hot compression molding was carried out. During the hot compression molding process, the flow channel of serpentine type, and U or V shapes were pressed onto the surface of the sample. The in-plane electrical conductivity and mechanical properties such as flexure strength, bulk density and shore hardness were then measured. Thus, a flow channel was investigated for accuracy of surface condition of flow channel dimensions (using a coordinate measurement machine), and subsequently compared with the actual drawings and its process ability. Based on electrical conductivity, flexure strength, bulk density and shore hardness, the sample with 15 wt% Fe was shown to yield the best results of 137.39 S/cm 3 , 34.04 MPa, 1.582 g/cm 3 , and 53.14 respectively. Meanwhile, based on the analysis of flow channel dimensions, the V shape is shown to give a smooth surface, with a dimensions difference between samples and the drawing of about -0.118 to 0.27%. Meanwhile, for the process ability, the V shape is much easier to release from the mold. In summary, this study revealed that the flow channel with V shape can be fabricated through the hot compression molding method with high accuracy.

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Section: Serpentine Type Flow Channelmentioning

confidence: 99%

Fabrication of a flow channel for the production of polymer composite bipolar plates through hot compression molding

et al. 2017

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“…He et al [5] conducted lithography and an etching experiment to generate the micro-pillar-based surface textures on a silicon wafer and fabricate the nano pillars on the micro pillars. Hung and Lin [6] studied the micro scale tool piece electrode and the fabricating high-aspect-ratio micro channel on bipolar plates by electrical discharge machining. The surface texture can be easily fabricated by these methods mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Electrically-Assisted Rolling Process of Corrugated Surface Microstructure with T2 Copper Foil

et al. 2019

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Electrically-assisted (EA) forming is a low-cost and high-efficiency method to enhance the formability of materials. In the study, EAF tensile tests are carried out to study the properties of T2 copper foil in an annealed state, and the effect of the electric current on the forming quality of corrugated foils is further studied in the EA rolling forming process. The result shows that the current reduces the flow stress and the fracture strain, which is different from the result of rolled samples. The joule heating effect on mechanical properties is significant in EA tension, and the softening effect of the surface layer can be observed at tensile strength, due to the grain size effect. Moreover, the current can weaken the grain size effect. In the rolling forming process, the influence of different electrical parameters on the forming height is remarkable, especially for the rolled T2 copper. The appropriate electrical parameters can improve the forming height, while keeping a small thickness thinning. Nevertheless, the high current density will lead to local rupture. This study proves that the current can improve the forming quality of the corrugated foils and is a promising surface texture forming process.

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“…Moreover, there are mechanical concerns, such as the fragility of thin graphite plates within the stack that have led to the exploration of different bipolar plate materials. Metallic bipolar plates are strong candidates for replacing graphite, offering great electrical and thermal conductivity while offering effective mechanical strength to support the forces within the stack even at a thinner plate thickness [2][3][4][5][6][7]. Stainless steel (SS) has shown satisfactory performance as a bipolar plate for thousands of hours of testing [8,9].…”

Section: Introductionmentioning

confidence: 99%

Investigation of bipolar plate materials for proton exchange membrane fuel cells

Shimpalee

Lilavivat

McCrabb

et al. 2016

International Journal of Hydrogen Energy

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Low-cost parts, materials, and production methods are important for effective establishment of polymer electrolyte membrane fuel cells (PEMFCs) into the commercial marketplace. The bipolar plate is one part that substantially impacts the PEMFC manufacturing cost. Metallic bipolar plates are an attractive alternative to graphite because they provide the necessary electrical and thermal conductivity and they offer good mechanical strength which supports the forces within the stack. Stainless steel, which is reasonably cheap, a good conductor, and corrosion resistant with high strength, has exhibited acceptable performance as a bipolar plate for several thousand hours of experiments. In this work, a through-mask electro-etching process was selected for fabrication of 304L and 430 stainless steel alloy bipolar plates for 25cm 2 PEMFC and they were compared against the graphite material. The key results revealed that stainless steel bipolar plates give comparable performance to graphite plates especially under well humidified conditions. At drier conditions, the resistance is the largest factor on the overall performance for all bipolar plate materials. Toray paper and Carbel CL GDLs give different performances under various bipolar plate materials and operating conditions. It is also shown that significant differences in channel depth profiles affect the overall performance.

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The fabrication of high-aspect-ratio micro-flow channels on metallic bipolar plates using die-sinking micro-electrical discharge machining

Cited by 55 publications

References 20 publications

Fabrication of a flow channel for the production of polymer composite bipolar plates through hot compression molding

Fabrication of a flow channel for the production of polymer composite bipolar plates through hot compression molding

Investigation of Electrically-Assisted Rolling Process of Corrugated Surface Microstructure with T2 Copper Foil

Investigation of bipolar plate materials for proton exchange membrane fuel cells

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