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<p>Phase-change heat transfer is essential for thermal management of proton exchange membrane fuel cells (PEMFCs) operating at high current densities and elevated temperature. In this study, test-scale pit-array microstructured bipolar plates with varied geometric parameters—line spacing, column spacing, and depth—were fabricated on 316&#xa0;L stainless steel via a nanosecond laser. An L9(3<sup>3</sup>) orthogonal experimental design was adopted, and visualized flow boiling experiments were conducted to characterize bubble size distribution, nucleation site density, and boiling heat flux. Orthogonal analysis revealed that line spacing is the dominant parameter governing boiling performance. Microstructured surfaces enhanced nucleation site density: densely arrayed pits confined bubbles to less than 0.5&#xa0;mm to suppress bubble coarsening, while sparser arrays, despite larger average bubble diameters, generated substantially more bubbles to compensate for size effects through quantity. Consequently, the optimally designed microstructure bipolar plate achieved a boiling heat flux exceeding 50,000&#xa0;W·m<sup>− 2</sup>—over five times that of the raw plate (~ 10,000&#xa0;W·m<sup>− 2</sup>)—attributed to synergistic effects of expanded heat transfer area, promoted nucleate boiling via tailored bubble size and distribution, and geometric confinement facilitating bubble stability and departure. This work provides experimental insights for laser-fabricated microstructure bipolar plates to reinforce PEMFC thermal management under demanding conditions.</p>

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Nanosecond laser-fabricated surface microstructures for enhanced phase-change heat transfer in PEMFCs operated at elevated temperature

  • 期刊论文

  • 发表日期：

    2026年2月10日

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  • Daijun Yang,
  • Chenqian Hua,
  • Yirui Lu,
  • Cheng Qu,
  • Junying Min,
  • Xiangmin Pan,
  • Bing Li,
  • Pingwen Ming

摘要

Phase-change heat transfer is essential for thermal management of proton exchange membrane fuel cells (PEMFCs) operating at high current densities and elevated temperature. In this study, test-scale pit-array microstructured bipolar plates with varied geometric parameters—line spacing, column spacing, and depth—were fabricated on 316 L stainless steel via a nanosecond laser. An L9(33) orthogonal experimental design was adopted, and visualized flow boiling experiments were conducted to characterize bubble size distribution, nucleation site density, and boiling heat flux. Orthogonal analysis revealed that line spacing is the dominant parameter governing boiling performance. Microstructured surfaces enhanced nucleation site density: densely arrayed pits confined bubbles to less than 0.5 mm to suppress bubble coarsening, while sparser arrays, despite larger average bubble diameters, generated substantially more bubbles to compensate for size effects through quantity. Consequently, the optimally designed microstructure bipolar plate achieved a boiling heat flux exceeding 50,000 W·m− 2—over five times that of the raw plate (~ 10,000 W·m− 2)—attributed to synergistic effects of expanded heat transfer area, promoted nucleate boiling via tailored bubble size and distribution, and geometric confinement facilitating bubble stability and departure. This work provides experimental insights for laser-fabricated microstructure bipolar plates to reinforce PEMFC thermal management under demanding conditions.