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CC BY V4.0, Open Access
Thesis
A perspective on lithium/sulfur battery design and development of power law design tool for hotspot mitigation using parallel microchannel heat exchanger
Washington State University
Master of Science (MS), Washington State University
2023
DOI:
https://doi.org/10.7273/000005083
Abstract
Lithium/sulfur cells that offer ultrahigh theoretical specific energy of 2600 W h kg-1 are considered a promising next-generation rechargeable battery system for electrification of transportation. However, commercialization of Li/S cells remains challenging, despite recent advancement in materials development for sulfur electrodes and electrolytes, due to several critical issues including insufficient obtainable specific energy and relatively poor cyclability. This perspective introduces electrode manufacturing and modeling methodologies and their current challenges. The obtainable specific energy of Li/S pouch cells are calculated for several parameters to demonstrate design requirements for high specific energy of >300 W h kg-1. Furthermore, prospects on rational modeling and manufacturing strategies are proposed to establish a new design standard for Li/S batteries. Finally, to address thermal management at cell and package scales, we propose a design tool for engineers in the form of a power law for hotspot mitigation using parallel microchannel heat exchangers. The tool relates local power density to the hydraulic diameter of a local microchannel. This study builds on earlier work by considering a wider range of flow distributions, conduction effects and hotspot power densities in a multivariable regression analysis. A laminar flow regime was considered, with Reynolds numbers between 200 and 2200, while the local hotspot was varied between three and eight times greater than surroundings. A computational analysis of several microchannel heat exchangers designed using this power law demonstrated it could balance temperature to a standard deviation of 2.61% on average over all Reynolds number. Compared to reference models with uniform channel size, the temperature standard deviation was reduced by 69.9% on average over all Reynolds numbers. However, a simultaneous average temperature rise of 11.1% was observed. A similar empirical analysis was conducted to validate the power law experimentally. We show a reduction in temperature standard deviation across a solid copper heat exchanger relative to a reference exchanger. However, the effect was muted significantly, reducing temperature standard deviation by only 21.6%, at the expense of a 48.0% rise in average temperature. Furthermore, we demonstrate power law efficacy is impacted by channel density, indicating the analytical development of the power law may require inclusion of conduction effects.
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Details
- Title
- A perspective on lithium/sulfur battery design and development of power law design tool for hotspot mitigation using parallel microchannel heat exchanger
- Creators
- Chase Allen McCreary
- Contributors
- Stephen Solovitz (Advisor)Jong Hoon Kim (Committee Member)Hua Tan (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Engineering and Computer Science (VANC), School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 106
- Identifiers
- 99901019836501842
- Language
- English
- Resource Type
- Thesis