81 research outputs found
Liquid Water Transport and Management for Fuel Cells
Full text linkLiquid water management is critical to proton exchange membrane fuel cell (PEMFC) performance and though the topic has received significant attention over the past couple of decades it remains a challenge as new materials and architectures are introduced in pursuit of higher efficiency and power densities. While water is necessary to facilitate efficient ionomer membrane function, its build-up in the liquid phase can saturate pores and reduce reactant gas diffusion rates. A primary challenge to liquid water transport at PEMFC length scales is that surface tension is dominant and so capillary effects at various interfaces must be understood and accounted for. Additionally, complex two-phase flow dynamics in the porous layers, as well as reactant channels, can have a large impact on overpotential and stability. This chapter discusses from a practical perspective liquid water production and transport in PEMFC systems, strategies to mitigate flooding, and new directions for the design and analysis of next-generation MEA and flow-field systems
Effective Transport Properties for Fuel Cells: Modeling and Experimental Characterization
Full text linkPolymer electrolyte fuel cells (PEFCs) are key elements in governments' plans to create a future hydrogen economy, providing clean, affordable electrical power for vehicles and portable electronic devices, among other applications. However, excessive cost and limited performance and durability still limit PEFC commercialization. At this stage of technological development, reducing Pt loading while improving performance and durability requires a tailored design of effective properties (e.g., thermal conductivity and diffusivity) and electrochemical activity (e.g., electrochemical surface area) of porous transport layers. Multifunctional thin, porous layers must be optimized by a combination of modeling and experimental work at different scales, ranging from a single layer up to cell (and stack) level(s). Even though this challenging task has already motivated a large body of work, further research on effective properties through the multiscale pore structure of PEFCs is needed to meet PEFC targets in the coming years
Fuel Cell Modeling and Optimization
Full text linkAs a highly efficient and cost-saving approach, modeling is significantly important in the development of proton exchange membrane fuel cells (PEMFCs). With the rapid development of computer technologies in the past three decades, PEMFC models have been upgraded from simple one-dimension (1D) single-cell models to sophisticated three-dimension (3D) multi-physics and multi-phase fuel-cell stack models, leading to the wider application of modeling in the diagnosis, design, optimization, and development of novel PEMFCs. This chapter provides the chronological development of PEMFC modeling approaches with a focus on those in modeling the catalyst layer and water formation and transport inside the PEMFCs. Numerical optimizations of PEMFCs with respect to electrodes, flow fields, fuel cell stacks, and operating conditions are summarised. The multi-variable optimization and data-driven modeling are also introduced in this chapte
Fuel Cell Fundamentals
Full text linkProton exchange membrane fuel cells (PEMFCs) are considered one of the viable solutions to the decarbonization of the transport sector. However, their performance and durability are yet to be competitive with internal engine vehicles due to the complex interaction of electrochemical and physical phenomena in PEMFCs. The electrochemical and physical phenomena that occurred in PEMFCs, including the polarization curves, profiles of the reactant and product species, velocities of species, as well as temperature distribution, could be described by coupling the reaction kinetics with the transport processes of mass, momentum, energy, and charge. In this chapter, the fundamentals and operating principles of PEMFCs are explained along with the governing equations that describe various electrochemical and multi-physics transport processes in PEMFCs
Fuel Cells for Transportation: An Overview
Full text linkFuel cells were invented more than 180 years ago. Intensive development for the space program in the 1960s was followed by even more intensive development in automotive applications since the 1990s. After almost every car manufacturer have had at least one prototype by the turn of the century, currently there are only two fuel cell car models available on the market. Is there a future for fuel cells for transportation? The future of fuel cells, including the fuel cells for transportation, is tightly related to the energy transition that is already taking place. In such a transition, hydrogen produced from renewable energy sources would enable the decarbonization of otherwise hard-to-decarbonize sectors. Fuel cells are the technology that will enable hydrogen’s use in transportation. Technology is ready, and political decisions have been made, so in the next decades, fuel cells will be widely used in transportation—not only in automobiles, but also in delivery vehicles, trucks, buses, coaches, trains, and even ships and airplanes.</p
Battery Management in Electric Vehicles: Current Status and Future Trends
No full textLithium-ion batteries are an indispensable component of the global transition to zero-carbon energy and are instrumental in achieving COP26's objective of attaining global net-zero emissions by the mid-century. However, their rapid expansion comes with significant challenges. The continuous demand for lithium-ion batteries in electric vehicles (EVs) is expected to raise global environmental and supply chain concerns, given that the critical materials required for their production are finite and predominantly mined in limited regions worldwide. Consequently, significant battery waste management will eventually become necessary. By implementing appropriate and enhanced battery management techniques in electric vehicles, the performance of batteries can be improved, their lifespan extended, secondary uses enabled, and the recycling and reuse of EV batteries promoted, thereby mitigating global environmental and supply chain concerns. Therefore, this reprint was crafted to update the scientific community on recent advancements and future trajectories in battery management for electric vehicles. The content of this reprint spans a spectrum of EV battery advancements, ranging from fundamental battery studies to the utilization of neural network modeling and machine learning to optimize battery performance, enhance efficiency, and ensure prolonged lifespan
A Perspective on the Challenges and Prospects of Realizing the Second Life of Retired EV Batteries
Full text linkAs electric vehicle (EV) adoption continues to surge globally, the question of what to do with retired EV batteries looms large. While these batteries may no longer meet the rigorous demands of automotive use, they often retain a significant portion of their capacity and functionality. This has led to growing interest in exploring second-life applications for retired EV batteries, ranging from stationary energy storage to grid stabilization and beyond. However, numerous challenges must be addressed to unlock the full potential of this emerging sector. This paper delves into the key challenges and prospects associated with the second life of retired EV batteries. It examines technical hurdles, such as battery degradation, safety concerns, and the development of efficient repurposing methods, along with regulatory and economic barriers, including standards for battery reuse, recycling infrastructure, and market dynamics. Additionally, it highlights the potential environmental benefits, including reduced carbon emissions and resource conservation. In conclusion, the second life of retired EV batteries presents both challenges and opportunities. Addressing technical, regulatory, and economic barriers will be essential for realizing the full potential of this growing sector. However, with continued innovation and collaboration across industries, the future looks bright for leveraging retired EV batteries to create a more sustainable energy ecosystem
Battery Management in Electric Vehicles - Current Status and Future Trends
Full text linkRechargeable batteries, particularly lithium-ion batteries (LiBs), have emerged as the cornerstone of modern energy storage technology, revolutionizing industries ranging from consumer electronics to transportation [1,2]. Their high energy density, long cycle life, and rapid charging capabilities make them indispensable for powering a wide array of applications, with electric vehicles (EVs) standing out as one of the most transformative domains. The rise of EVs represents a pivotal shift in the automotive industry, driven by the urgent need to mitigate climate change and reduce greenhouse gas emissions
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