The Self-Adaptive Fuel Supply Mechanism in Micro DMFC Based on the Microvalve

Abstract

To achieve a self-adaptive fuel supply mechanism for the micro direct methanol fuel cell (μDMFC), we designed and developed a thermal control microvalve channel structure, where we considered the relationship between the temperature characteristics, viscosity, and velocity of the methanol solution. Both the single channel model and three-dimensional cell model for the microvalve were established using the COMSOL Multiphysics program. The results demonstrated that in the microvalve channel, the viscosity of the solution decreased, and the flow rate at the microvalve outlet increased with the increasing temperature. Meanwhile, the geometry structure of the microvalve single channel was optimized, so that the effect of the control speed of the microvalve under temperature changes became more prominent. In the full-cell model analysis, a low-velocity methanol solution at the low current density can significantly inhibit methanol crossover. At the high current densities, an increase in the methanol solution flow rate was beneficial to an increase in the cell reaction output. The μDMFC was fabricated and the experiment was conducted, where the results showed that the power density of the self-adaptive cell reached a maximum value of 16.56 mW/cm2 in 2 M methanol solution, which was up to 7% better than conventional cell performance. The proposed microvalve structure can effectively improve the output power of the μDMFC during the whole reaction process, and it may improve the stability of the cell operation.

Passive Small Direct Alcohol Fuel Cells for Low-Power Portable Applications: Assessment Based on Innovative Increments since 2018

“…Accordingly, when the flow path is a hydrophilic surface, the CO 2 bubbles move more easily in the channels and are more easily discharged from the flow field. Thus, on the basis of the relationship linking the viscosity, velocity, and methanol solution temperature at different current densities, the research group also reported the development of a thermal control microvalve channel structure [113]. The expectation was that the microvalve structure could achieve a self-adaptive fuel supply and effectively increase the power and stability during the PS-DMFC operation.…”

A Critical Assessment on Functional Attributes and Degradation Mechanism of Membrane Electrode Assembly Components in Direct Methanol Fuel Cells

“…Studies reported that the MCO mostly relies on the operating temperature [74][75][76] and the method of delivering the fuel [77]. It is given that the rate of fuel/oxidant delivered, and their concentration will substantially impact MCO [78].…”

Performance Optimization of μDMFC with Foamed Stainless Steel Cathode Current Collector

“…µDMFC is a new type of energy device with the advantages of having a simple structure, easy operation, and emitting low pollution, which is widely used in aerospace, military, and communication fields [1][2][3][4]. The current collector plays an important role by collecting the conduction current and reasonably distributing the gas and water in the µDMFC.…”