Buoyancy Control Device Enabled by Reversible Proton Exchange Membrane Fuel Cells for Fine Depth Control

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Jalal Yazji ◽  
Alicia Li Jen Keow ◽  
Hamza Zaidi ◽  
Luke T. Torres ◽  
Christopher Leroy ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Dynamic Model ◽  
Proton Exchange Membrane ◽  
Water Electrolysis ◽  
Control Device ◽  
Proton Exchange ◽  
Underwater Robots ◽  
Neutral Buoyancy ◽  
Depth Control ◽  
Buoyancy Control

Abstract Fine buoyancy control is essential for underwater robots to maintain neutral buoyancy despite dynamic changes in environmental conditions. This paper introduces a novel buoyancy control system that uses reversible fuel cells (RFC) as a mass-to-volume engine to change the underwater robots' buoyancy. The RFC uses both the water electrolysis process and fuel cell reaction to produce and consume gases in a flexible bladder for volume change. Unlike conventional actuators such as motors and pistons used in buoyancy control, this mechanism is silent, compact, and energy-efficient. A dynamic model that described the dynamics of the RFC-enabled buoyancy change is presented. Then, a proportional-derivative (PD) controller is designed to position the device at any depth underwater. A prototype device is built to validate the dynamic model and the performance of the feedback controller. Experimental results demonstrate a fine depth control performance with 4 cm accuracy and 90 s settling time. The compact buoyancy design is readily integrable with small underwater robots for fine depth change allowing the robots to save actuation energy.

Applications of two dimensional material-MXene for proton exchange membrane fuel cells (PEMFCs) and water electrolysis

2020 ◽  
Vol 16 ◽  
Author(s):  
Chanchan Fan ◽  
Peng Zhang ◽  
Ranran Wang ◽  
Yezhu Xu ◽  
Xingrui Sun ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Water Splitting ◽  
Proton Exchange Membrane ◽  
Layer Structure ◽  
Metal Layer ◽  
Water Electrolysis ◽  
Proton Exchange ◽  
Two Dimensional ◽  
Max Phases ◽  
Early Transition Metal

: A new kind of two-dimensional (2D) materials MXene (early transition metal carbides, nitrides and carbonitrides) is obtained by selective etching the A element from the MAX phases. MXene exhibits both the metallic conductivity and the hydrophilic nature due to its metal layer structure and hydroxyl or oxygen terminated surfaces. This review provides an overview of the MXene used in the electrolytes and electrodes for the fuel cells and water splitting. MXene with functional groups termination could construct ion channels that significantly benefits to the ion conductivity through the electrolyte. The metal supported by MXene interaction offers electronic, compositional, and geometric effects that could enhance the catalytic activity and stability. MXene have already shown promising performance for fuel cells and water electrolysis. Herein, the etching and intercalation methods of MXene in recent years are summarized. The applications of MXene for fuel cells electrolyte, catalyst and water splitting catalyst are revealed to provide more brief idea for MXene used as new energy materials.

Water electrolysis plateau in voltage reversal process for proton exchange membrane fuel cells

2020 ◽  
Vol 455 ◽  
pp. 227952 ◽  
Author(s):  
Chao Cai ◽  
Zhaohui Wan ◽  
Yan Rao ◽  
Wei Chen ◽  
Jiangfeng Zhou ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Water Electrolysis ◽  
Proton Exchange ◽  
Reversal Process ◽  
Exchange Membrane

Modeling and Control of Artificial Swimming Bladder Enabled by IPMC Water Electrolysis

2018 ◽  
Author(s):  
Alicia Keow ◽  
Zheng Chen
Keyword(s):  
Pid Controller ◽  
Tap Water ◽  
Deep Ocean ◽  
Water Electrolysis ◽  
Open Loop ◽  
Metal Composite ◽  
Gas Generation ◽  
Underwater Robots ◽  
Depth Control ◽  
Buoyancy Control

Underwater robots with buoyancy control capability are highly desirable in deep ocean exploration for underwater environment monitoring and intelligent collection. In this paper, a prototype of buoyancy control device powered by ionic polymer metal composite (IPMC) is developed. An IPMC is used for enhancing the water electrolysis of tap water and separating the gases produced. The produced hydrogen and oxygen gases are stored in two separate chambers. Collection of these gases increase the volume of water displaced by the device, hence, increases its buoyancy. Two solenoid valves are used to control the release of gases to decrease the device’s buoyancy. Using a dynamic model developed in our previous work, the parameters of the model are identified through an open-loop test. A PID controller is then designed for close-loop depth control. The PID controller uses the error in depth to estimate the desired gas generation/releasing rate. It then calculates the duty cycle of the pulse-width modulation (PWM) signal used for driving the solenoid valves. The closed-loop depth control is verified both through simulation and real-time experiment, showing satisfactory results.

Highly proton conductive membranes based on carboxylated cellulose nanofibres and their performance in proton exchange membrane fuel cells

2019 ◽  
Author(s):  
Valentina Guccini ◽  
Annika Carlson ◽  
Shun Yu ◽  
Göran Lindbergh ◽  
Rakel Wreland Lindström ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Surface Charge ◽  
Proton Exchange Membrane ◽  
Membrane Surface ◽  
Proton Exchange ◽  
Membrane Thickness ◽  
Fuel Cell Performance ◽  
Cellulose Nanofibres ◽  
Exchange Membrane

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g<sup>-1</sup>), counterion (H<sup>+</sup>or Na<sup>+</sup>), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH as measured by Small Angle X-ray scattering shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na<sup>+</sup>or H<sup>+</sup>). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm<sup>-1</sup>at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.<br>

Latest Trends and Challenges In Proton Exchange Membrane Fuel Cell (PEMFC)

2017 ◽  
Vol 10 (1) ◽  
pp. 96-105 ◽  
Author(s):  
Mohammed Jourdani ◽  
Hamid Mounir ◽  
Abdellatif El Marjani
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Total Cost ◽  
Cell Efficiency ◽  
Technical Advances ◽  
Exchange Membrane

Background: During last few years, the proton exchange membrane fuel cells (PEMFCs) underwent a huge development. Method: The different contributions to the design, the material of all components and the efficiencies are analyzed. Result: Many technical advances are introduced to increase the PEMFC fuel cell efficiency and lifetime for transportation, stationary and portable utilization. Conclusion: By the last years, the total cost of this system is decreasing. However, the remaining challenges that need to be overcome mean that it will be several years before full commercialization can take place.This paper gives an overview of the recent advancements in the development of Proton Exchange Membrane Fuel cells and remaining challenges of PEMFC.

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