Mitigating Water Accumulation in Fuel Cells

Water extraction system for a fuel cell stack to extract water from the exhaust flow and provide it back to the fuel cell stack to maintain hydration levels. The system uses a condenser to cool the exhaust, an extractor to remove water, a turbine to extract energy from the dehumidified exhaust, and a reheater to transfer heat from the turbine exhaust back to the dehumidified exhaust. This allows extracting water, extracting energy, and transferring heat in a closed loop.

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<title>Abstract</title> In a Proton Exchange Membrane Fuel Cell (PEMFC), the geometry of flow channels plays critical role in mass transport, electrochemical current distribution, and water management. The objective this study is to investigate effect obstacle aspect ratio (AR) cathode channel on cell performance under various operating conditions (temperature 333363 K, pressure 14 atm, anode/cathode relative humidity 0100%). To end, three-dimensional numerical model was developed, governing equations for species energy, electric were solved using computational fluid dynamics (CFD) with finite-volume method. geometric parameters included AR = 0 1 rectangular obstacles both anode channels, boundary corresponding temperature, pressure, simulated independently. results showed that intermediate-sized 0.250.50 significantly enhance oxygen transport reduce concentration losses; example, at mid-range temperatures (343353 K) pressures 12 power density increased by more than 20%. Specifically, 343 K 0.75, rose from 0.3769 0.5289 W/cm. At higher (34 atm), however, be... Read More

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A condensate water drain control system for fuel cells that can accurately drain condensate water from the fuel cell stack even when the water level sensor fails. The system estimates the fuel cell's chemical reaction amount and opens the drain valve based on that. When the valve is open, it closes it again based on the fuel supply state to prevent over-draining. This allows condensate drainage without relying on the sensor.

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&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;This study presents a novel biomimetic flow-field concept that integrates triply periodic minimal surface (TPMS) porous architectures with hierarchical leaf-vein-inspired distribution zone, fabricated through 3D printing. By mimicking natural transport systems, the proposed design enhances oxygen delivery and water removal in proton exchange membrane fuel cells (PEMFCs). The results showed &lt;b&gt;&lt;i&gt;I&lt;/i&gt;&lt;/b&gt;-FF &lt;b&gt;&lt;i&gt;G&lt;/i&gt;&lt;/b&gt;-FF significantly improved mass management compared to conventional CPFF. integrated &lt;b&gt;&lt;i&gt;I&lt;/i&gt;&lt;/b&gt;-FF-LDZ achieves up 32% improvement power density at 1.85 &lt;b&gt;&lt;i&gt;A&lt;/i&gt;&lt;/b&gt;/&lt;b&gt;&lt;i&gt;cm&lt;/i&gt;&lt;/b&gt;&lt;sup&gt;&lt;b&gt;2&lt;/b&gt;&lt;/sup&gt;@0.4 V delays onset of losses. also reveals optimizing volume fraction &lt;b&gt;&lt;i&gt;V&lt;/i&gt;&lt;/b&gt;&lt;sub&gt;&lt;b&gt;&lt;i&gt;f&lt;/i&gt;&lt;/b&gt;&lt;/sub&gt; affects gas penetration, lower (30%) improving performance mass-limited r... Read More

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A fuel cell exhaust system that efficiently separates water from the exhaust gas without additional flow obstructions. The system has a condenser to condense water vapor from the exhaust and a separator with a curved channel surrounded by a chamber. The chamber collects condensed water as it flows through the channel due to centrifugal and gravitational forces. This eliminates the need for further water separation measures in the fuel cell exhaust system.

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This study investigates the effects of anode and cathode inlet flow rates () on power performance bipolar plates in a polymer electrolyte membrane fuel cell (PEMFC). The primary objective is to derive optimal rate conditions by comparatively analyzing concentration loss IV curve crossover phenomena at anode, thereby establishing that prevent reactant depletion water flooding. A single-cell computational model was constructed assembling commercial plate with gas diffusion layer (GDL), catalyst (CL), proton exchange (PEM). simulates current density generated electrochemical oxidation-reduction reactions. Hydrogen oxygen were supplied 1:3 ratio under five proportional conditions: hydrogen (mH2 = 0.763.77 LPM) (mO2 2.3911.94 LPM). ButlerVolmer equation employed voltage drop due overpotential, while numerical simulations incorporated contact resistivity, surface permeability, porous media properties. Simulation results demonstrated 24.40% increase when raising mH2 from 2.26 3.02 LPM mO2 7.17 9.56 LPM. Further increases 3.77 11.94 yielded 10.20% improvement, indicati... Read More

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Closed loop cooling system for fuel cell stacks that enables efficient water management and cooling without the need for external water injection or exchange columns. The system recycles water from the fuel cell exhaust streams to cool the stack and maintain hydration. It uses a controller to automatically manage the water injection and removal based on stack conditions. This allows optimized water management for performance and reduces contamination compared to external water injection. The controller calculates the water balance and adjusts injection based on stack water generation, stack temperature, and cooling needs.

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Real-time monitoring of water flooding in fuel cells using optical imaging and machine learning to predict cathode pressure drops. The system involves capturing high-speed images of the cathode backing layer during operation and using computer vision techniques to detect water droplets as anomalous pixels surrounded by humidity. A mask is applied to ignore background noise and separate water droplets inside each channel. Machine learning models are trained to predict cathode pressure using the extracted water features. This allows real-time monitoring of water flooding without extensive resources and equipment, as well as estimating the effect of water flooding on oxygen pressure.

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Abstract The porosity of the Gas Diffusion Layer (GDL) has an impact on mass transport within Proton Exchange Membrane Fuel Cells (PEMFC), thus affecting output performance cells. In this research, a three-dimensional (3D) geometric model PEMFC with two-channel serpentine flow field at anode and seven-channel sinusoidal cathode was created. also considered water mechanisms in electrolyte phase change between surrounding pores. Simulations were conducted for GDL porosities 50%, 40%, 30%, 20%, 10%, respectively. results show that medium to high current density range, significantly affects cell performance. As increases, uniformity distribution membrane is enhanced. Under given voltage condition, increasing leads higher power output. Compared 50% peak 40% greater.

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Overhumidification is a critical challenge to the performance and durability of polymer electrolyte fuel cells (PEFCs). This review evaluates current methods for detecting quantifying overhumidification, focusing on simulation, imaging, sensor technologies. Each method assessed based five key criteria: precision, sensitivity, realtime capability, interpretation complexity, validation strength. Physically grounded modeling approaches such as computational fluid dynamics lattice Boltzmann offer high accuracy but are computationally demanding. Imaging techniques, including neutron imaging magnetic resonance provide valuable insight face limitations regarding scalability application. Sensor technologies, from commercial sensors artificial intelligenceenhanced nanostructured platforms, enable monitoring require improved robustness under operando conditions. By comparing these techniques individually collectively, this identifies promising hybrid strategies outlines research priorities achieving intelligent, water management in PEFCs.

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Abstract The flow field in a proton exchange membrane fuel cell is essential for efficiently managing water removal, especially at high current densities. This study designs that facilitates removal and presents considerations its implementation. A 3-path serpentine channel has been adopted as the reference model. When contact resistance not considered, performance of check-pattern superior under all voltage conditions, with maximum increase 5.1 %. considering resistance, similar most conditions; however, densities, checked pattern exhibits performance, improving by 5 to 7.2 larger rib area hinders but reduces resistance. Therefore, should be designed both together.

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The air-cooled fuel cell is a promising energy conversion device. However, the characteristics of forced convection often rapidly expel water from gas diffusion layer (GDL) into flow field, which reduces humidity membrane electrode assembly (MEA). Under low-humidity conditions, proton conductivity exchange (PEM) decreases, thereby impairing performance and durability cell. Inspired by tortuous transport pathways in maze model, we designed GDL with maze-like structure (M-GDL) to extend path, increasing internal We evaporation test verify loss resistance GDL. M-GDL exhibits remarkable loss, rate 0.35 mg min-1 cm-2, significantly lower than 0.79 cm-2 observed for commercial This extended retention capability leads notable increase cell, peak power density 0.77 W more double that GDL, where only 0.4 cm-2. work presents strategy mitigate issue low cells.

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Cooling system for fuel cell systems that efficiently dissipates heat while humidifying the fuel cell gases. The system uses a gas separator to extract steam from the return line, feed it back into the fuel supply line, and a water feed device to compensate for the steam separation. This allows humidification without excessive water buildup. The steam extraction also reduces the amount of water needed in the supply line. The system can also condense exhaust steam and feed it back into the supply line.

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Fuel cell system with improved water management without separate blowers. It has a unique inlet area change part between the branch flow paths to the fuel cell stacks. This part allows selectively increasing/decreasing the inlet areas of the branch paths. By temporarily increasing the supply flow rate to the stacks, it mimics higher stoichiometric ratios to enhance water discharge. This reduces flooding and improves performance without separate blowers.

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Temperature gradients across the catalyst-coated membrane influence water accumulation in anode gas diffusion layer (GDL) of polymer electrolyte fuel cells, yet experimental investigations remain limited. This study systematically examines impact a through-plane temperature gradient on distribution using operando synchrotron X-ray radiography. Lowering relative to cathode causes increased saturation GDL. behavior is mainly due phase-transition effects, specifically enhanced condensation and suppressed evaporation. A 0.168 observed under-rib regions GDL, which relatively high compared commonly reported values. These findings support growing recognition that can occur under certain gradients, highlighting crucial role need for improved GDL designs effective management.

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Preventing water accumulation and freeze-ups between the internal and external airtight lines of a fuel cell stack by removing portions of the external airtight gasket around manifolds. This allows any water or gas that enters the closed space between the lines to drain out instead of stagnating. The internal gasket still seals the reactant flow paths. The cutouts in the external gasket prevent a closed space between the lines that can trap water and cause issues like corrosion, freezing, and inspection errors.

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Fuel cell system that maintains optimal humidity and temperature for stack operation by adjusting the humidity and airflow of external air supplied to the stack. The system has valves to control exhaust air recirculation, bypassing humidifier, and stack airflow based on sensed stack and external air conditions. It also compensates stack air pressure and adjusts recirculation based on stack and intake temperatures. This prevents flooding from over-humidified air and power loss from dry air while maintaining differential pressure.

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Abstract Efficient transport of liquid water within the cathode channel plays a pivotal role in enhancing management proton exchange membrane fuel cells (PEMFCs). Employing multiple relaxation time lattice Boltzmann method (MRT-LBM), simulations are carried out for droplet aggregation and emission processes on surface with polytetrafluoroethylene (PTFE) shedding ratios 0%, 20%, 40%. Through analysis temporal dynamic evolutions position, shape, as well resulting pressure difference flow channel, it is revealed that PTFE ratio increases, deformation droplets during process becomes smaller. However, discharge process, shape turns to be more unstable, leading smaller average greater resistance movement droplets. The cases 20% 40% increases by 33.758% 93.329%, respectively, compared case no shedding.

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The performance and durability of proton-exchange membrane fuel cells (PEMFCs) are dependent on flow, humidifying water, outgoing water management. Unlike conventional flow fields with linear channels, the complex 3D fieldfeaturing repeating baffles along channel, known as baffle designinduces a micro-scale interface flux between gas diffusion layer (GDL) fields. Thus, an intensive oxygen is created that removes excess from GDL, thereby improving cell efficiency. Another approach for channel design Turing field, which resembles organization fluid flows in natural objects such leaves, lungs, blood system. This enhances distribution inlet significantly compared traditional designs. present study aims to combine advantages both field designs provide model investigations influence mixed efficiency PEMFCs. It was established achieves highest electrode current density 1.2 A/cm2, outperforming other Specifically, it 20% improvement over design, reaching 1.0 A/cm2 generating three times more than delivers 0.4 A/cm2. In contrast, serpentine exhibit lowest density. provides better utiliz... Read More

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&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;The utilization of hydrogen in low-temperature Proton Exchange Membrane Fuel Cells (PEMFCs) stands out as a compelling prospect for driving widespread shift towards green industry practices. Despite significant advancements, comprehensive understanding water behaviour and dynamics within PEMFCs remains crucial their extensive integration propulsion applications. Striking delicate balance between flooding drying conditions poses challenge achieving stable efficient PEMFC operation. In this study, preliminary experimental investigation was conducted focusing on carbon-paper Gas Diffusion Layer (GDL) gas channel walls. The static, advancing receding contact angles were measured utilized boundary simulations. influence membrane humidity also examined during the campaign. 3D CFD simulations performed straight portion with selected domain length 5 mm section 1x1 mm. Two classes droplets (0.05 mm&lt;sup&gt;3&lt;/sup&gt; 0.075 mm&lt;sup&gt;3&lt;/sup&gt;) deposited middle double GDL wall. To account difference angles, r... Read More

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