Bipolar Plates for PEMFCs

2014 ◽  
Vol 11 (4) ◽  
Author(s):  
C. A. C. Sequeira ◽  
L. Amaral

Proton exchange membrane fuel cells (PEMFCs) have many advantages among the various types of fuel cells, such as high energy density, low temperature operation, near-zero pollution, and quick starting. Thereby, PEMFCs have been considered as the most promising alternative power sources in the transportation and stationary fields. Among the components of PEMFCs, the bipolar plates are the most representative regarding cost and volume, however, they have relevant functions on the fuel cell stack. There are about 500 bipolar plates in a PEMFC for a typical passenger car and, thus, the commercialization of the fuel cell technology becomes quite challenging. Important key aspects for a successful fuel cell stack are the design and the manufacturing process of the bipolar plate. For efficient mass production, the cycle time of the process is even more important than the material costs. It is, therefore, very important that the used material is appropriate for a fast manufacturing process. Recent developments are overcoming these issues, leading to improvements on the overall fuel cell performance and durability.

Author(s):  
Mohammad Kazemi Nasrabadi ◽  
Amir Ebrahimi-Moghadam ◽  
Mohammad Hosein Ahmadi ◽  
Ravinder Kumar ◽  
Narjes Nabipour

Due to low working temperature, high energy density and low pollution, proton exchange fuel cells have been investigated under different operating conditions in different applications. Using platinum catalysts in methanol fuel cells leads to increasing the cost of this kind of fuel cell which is considered as a barrier to the commercialism of this technology. For this reason, a lot of efforts have been made to reduce the loading of the catalyst required on different supports. In this study, carbon black (CB) and carbon nanotubes (CNT) have been used as catalyst supports of the fuel cell as well as using the double-metal combination of platinum-ruthenium (PtRu) as anode electrode catalyst and platinum (Pt) as cathode electrode catalyst. The performance of these two types of electro-catalyst in the oxidation reaction of methanol has been compared based on electrochemical tests. Results showed that the carbon nanotubes increase the performance of the micro-fuel cell by 37% at maximum power density, compared to the carbon black. Based on thee-electrode tests of chronoamperometry and voltammetry, it was found that the oxidation onset potential of methanol for CNT has been around 20% less than CB, leading to the kinetic improvement of the oxidation reaction. The current density of methanol oxidation reaction increased up to 62% in CNT sample compared to CB supported one, therefore the active electrochemical surface area of the catalyst has been increased up to 90% by using CNT compared to CB which shows the significant rise of the electrocatalytic activity in CNT supported catalyst. Moreover, the resistance of the CNT supported sample to poisonous intermediate species has been found 3% more than CB supported one. According to the chronoamperometry test results, it was concluded that the performance and sustainability of the CNT electro-catalyst show remarkable improvement compared to CB electro-catalyst in the long term.


Author(s):  
Saeed Moghaddam ◽  
Eakkachai Pengwang ◽  
Kevin Lin ◽  
Rich Masel ◽  
Mark Shannon

The increasing demand for high energy density power sources driven by advancements in portable electronics and MEMS devices has generated significant interest in development of micro fuel cells. One of the major challenges in development of hydrogen micro fuel cells is the fabrication and integration of auxiliary systems for generation and delivery of fuel to the membrane electrode assembly (MEA). In this paper, we report the development of a millimeter-scale (3×3×1 mm3) micro fuel cell with on-board fuel and control system. Hydrogen is generated in the device through reaction between water and a metal hydride. The device incorporates a new control mechanism for hydrogen generation that occupies only 50 nL volume (less than 0.5% of the total device volume). More importantly, the control mechanism is self-regulating and does not consume any power, enabling the micro fuel cell to operate passively, similar to a battery.


Author(s):  
Habib Forootan Fard ◽  
Mohammad Kazemi nasrabadi ◽  
Amir Ebrahimi-Moghadam ◽  
Mohammad Hossein Ahmadi ◽  
Ely Salwana ◽  
...  

Due to low working temperature, high energy density and low pollution, proton exchange fuel cells have been investigated under different operating conditions in different applications. Using platinum catalyst in methanol fuel cell leads to increasing the cost of this kind of fuel cells which is considered as a barrier to commercialism of this technology. For this reason, a lot of efforts have been made to reduce the loading of the catalyst required on different supports. In this study, carbon black (CB) and carbon nanotubes (CNT) have been used as catalyst supports of the fuel cell as well as using the double-metal combination of platinum-ruthenium (PtRu) as anode electrode catalyst and platinum (Pt) as cathode electrode catalyst. The performance of these two types of the electro-catalyst in oxidation reaction of methanol has been compared based on electrochemical tests. Results showed that the carbon nanotubes increase the performance of the micro-fuel cell by 37% at maximum power density, compared to the carbon black. Based on thee-electrode tests of chronoamperometry and voltammetry, it was found that oxidation onset potential of methanol for CNT has been around 20% less than CB, leading to the kinetic improvement of the oxidation reaction. In addition, the active electrochemical surface area of catalyst has been increased up to 90% by using CNT compared to CB which shows the significant rise of the electrocatalytic activity in CNT supported catalyst with 62% increase in current density of methanol oxidation reaction respect to CB supported one. Moreover, the resistance of CNT supported sample to poisonous intermediate species has been found 3% more than CB supported one. According to the chronoamperometry test results, it was concluded that the performance and sustainability of NCT electro-catalyst shows remarkable improvement compared to CB electro-catalyst in long term.


Author(s):  
Fikile R. Brushett ◽  
Adam S. Hollinger ◽  
Larry J. Markoski ◽  
Paul J. A. Kenis

A continuously growing need for high energy density miniaturized power sources for portable electronic applications has spurred the development of a variety of microscale fuel cells. For portable applications, membrane-based fuel cells using small organic fuels (i.e., methanol, formic acid) are among the most promising configurations as they benefit from the high energy density and easy storage of the liquid fuels. Unfortunately, the performance of these fuel cells is often hindered by membrane-related issues such as water management (i.e., electrode dry-out / flooding) and fuel crossover. Furthermore, high costs of, for example, catalysts and membranes as well as durability concerns still hinder commercialization efforts. To address these challenges we have developed membraneless laminar flow-based fuel cells (LFFCs), which exploit microscale transport phenomena (laminar flow) to compartmentalize streams within a single microchannel. The properties of various fuel and media flexible LFFCs will be presented and novel strategies for improving fuel utilization and power density will be discussed. Furthermore, the performance of a scaled-out 14-channel LFFC prototype is presented. We have also developed a microfluidic fuel cell as a powerful analytical platform to investigate and optimize the complex processes that govern the performance of catalysts and electrodes in an operating fuel cell. This platform bridges the gap between a conventional 3-electrode electrochemical cell and a fuel cell, as it allows for standard electrochemical analysis (e.g., CV, CA, EIS) as well as fuel cell analysis (e.g., IV curves).


Author(s):  
B. Banazwski ◽  
R. K. Shah

Batteries have not kept pace with the advancing technology that they power, but they are used in everything from cell phones, laptop computers, and toys to consumer electronics. Compared to the devices that they power, batteries are relatively heavy, expensive per unit power they produce, last a relatively short time and recharging them takes hours. The solution to this less than desired means of a power source is fuel cells. Three fuel cells, also referred to as air breathers, considered are proton exchange membrane fuel cell (PEMFC), direct methanol fuel cells (DMFC), and direct formic acid fuel cells (DFAFC). We will discuss these fuel cells for micro and portable applications within the power range of 0.5 to 20 W for potential replacement of batteries. The reason for developing such fuel cells is to harness the power stored in the high energy density fuels, which provides more power and longer run times for the same packaging volume as batteries. The advantages of each type of fuel cell over batteries, their unique characteristics, technical drawbacks, current and future consumer products, and commercial issues will be outlined in this paper. A growing mobile society and consumer demands will drive the development of fuel cell technology forward as batteries reach their limit.


Author(s):  
Lei Du ◽  
Gaixia Zhang ◽  
Shuhui Sun

AbstractProton exchange membrane (PEM) fuel cells have gained increasing interest from academia and industry, due to its remarkable advantages including high efficiency, high energy density, high power density, and fast refueling, also because of the urgent demand for clean and renewable energy. One of the biggest challenges for PEM fuel cell technology is the high cost, attributed to the use of precious platinum group metals (PGM), e.g., Pt, particularly at cathodes where sluggish oxygen reduction reaction takes place. Two primary ways have been paved to address this cost challenge: one named low-loading PGM-based catalysts and another one is non-precious metal-based or PGM-free catalysts. Particularly for the PGM-free catalysts, tremendous efforts have been made to improve the performance and durability—milestones have been achieved in the corresponding PEM fuel cells. Even though the current status is still far from meeting the expectations. More efforts are thus required to further research and develop the desired PGM-free catalysts for cathodes in PEM fuel cells. Herein, this paper discusses the most recent progress of PGM-free catalysts and their applications in the practical membrane electrolyte assembly and PEM fuel cells. The most promising directions for future research and development are pointed out in terms of enhancing the intrinsic activity, reducing the degradation, as well as the study at the level of fuel cell stacks.


2015 ◽  
Vol 12 (6) ◽  
pp. 591-606 ◽  
Author(s):  
Venkateswarlu Velisala ◽  
G. Naga Srinivasulu ◽  
B. Srinivasa Reddy ◽  
K. Venkata Koteswara Rao

Fuel cells technologies are the most promising green energy technologies for diverse applications. One of the fastest growing areas is the portable electronic applications where the power range is the order of 1–100 W. For most of the portable electronic devices, rechargeable battery is the major energy source. Due to limitations like limited capacity, requirement of external power for recharge have led many researchers to look for alternative power sources to power portable electronic devices. The high energy density of fuel cells makes them very attractive alternative to batteries for portable power applications. There are a variety of fuel cell technologies being considered to replace batteries in portable electronic equipment. Direct Liquid Fuel Cells (DLFCs) have attracted much attention due to their potential applications as a power source for portable electronic devices. The advantages of DLFCs over hydrogen fed PEM fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. Unlike batteries, fuel cells need not be recharged, merely refueled. This paper provides an overview on challenges of DLFCs (Direct Liquid Fuel Cells), like fuel crossover, cost, durability, water management, weight and size along with approaches being investigated to solve these challenges. Portable Fuel Cell Commercialization Targets for future and producers of portable fuel cells across the globe are also discussed in this paper.


Author(s):  
Jay W. LaGrange ◽  
William F. Smith

Recent developments in applications such as Pulsed Power, Space, High Altitude Long Endurance (HALE) aircraft and underwater vehicles have created interest in the application of air-independent fuel cells. The attraction for such systems has been the potential for high performance, long life and high energy density allowing for extended mission operations and simple recharge. A limitation of such systems, to date, has been the relatively complicated balance of plant required for system operation. This typically requires circulation of one or both reactants to remove product water and distribute reactants. These parasitic systems can reduce the overall efficiency and maintainability of the system, create noise and inhibit or prevent certain missions. Under the sponsorship of the NASA Glenn Research Center Infinity has developed a Non Flow-Through (NFT) Advanced Product Water Removal (APWR) Proton Exchange Membrane Fuel Cell system. The design eliminates the need to actively circulate reactants and can remove water directly from the reaction site within the cell. This low temperature, compact, lightweight technology projects to a system with the operational simplicity and reliability of a battery but with the performance and recharge capability of fuel cells. This paper will report on the operational characteristics, performance and benefits of Infinity’s APWR fuel cell. An update on development status and recent testing results will be included.


Author(s):  
Mohammad Kazemi Nasrabadi ◽  
Habib Forootan Fard ◽  
Amir Ebrahimi-Moghadam ◽  
Mohammad Hossein Ahmadi ◽  
Ravinder Kumar ◽  
...  

Due to low working temperature, high energy density and low pollution, proton exchange fuel cells have been investigated under different operating conditions in different applications. Using platinum catalyst in methanol fuel cell leads to increasing the cost of this kind of fuel cells which is considered as a barrier to the commercialism of this technology. For this reason, a lot of efforts have been made to reduce the loading of the catalyst required on different supports. In this study, carbon black (CB) and carbon nanotubes (CNT) have been used as catalyst supports of the fuel cell as well as using the double-metal combination of platinum-ruthenium (PtRu) as anode electrode catalyst and platinum (Pt) as cathode electrode catalyst. The performance of these two types of the electro-catalyst in oxidation reaction of methanol has been compared based on electrochemical tests. Results showed that the carbon nanotubes increase the performance of the micro-fuel cell by 37% at maximum power density, compared to the carbon black. Based on thee-electrode tests of chronoamperometry and voltammetry, it was found that oxidation onset potential of methanol for CNT has been around 20% less than CB, leading to the kinetic improvement of the oxidation reaction. In addition, the active electrochemical surface area of catalyst has been increased up to 90% by using CNT compared to CB which shows the significant rise of the electrocatalytic activity in CNT supported catalyst with 62% increase in current density of methanol oxidation reaction respect to CB supported one. Moreover, the resistance of CNT supported sample to poisonous intermediate species has been found 3% more than CB supported one. According to the chronoamperometry test results, it was concluded that the performance and sustainability of NCT electro-catalyst shows remarkable improvement compared to CB electro-catalyst in long term.


Author(s):  
Shuiyun Shen ◽  
Ziwen Ren ◽  
Silei Xiang ◽  
Shiqu Chen ◽  
Zehao Tan ◽  
...  

Abstract Proton exchange membrane fuel cell (PEMFC) is a crucial route for energy saving, emission reduction and the development of new energy vehicles because of its high power density, high energy density as well as the low operating temperature which corresponds to fast starting and power matching. However, the rare and expensive Pt resource greatly hinders the mass production of fuel cell, and the development of highly active and durable non-precious metal catalysts toward the oxygen reduction reaction (ORR) in the cathode is considered to be the ultimate solution. In this article, a highly active and durable Fe-N-C catalyst was facilely derived from metal organic framework materials (MOFs), and a favorable structure of carbon nanotubes (CNTs) were formed, which accounts for a desired good durability. The as-optimized catalyst has a half-wave potential of 0.84V for the ORR, which is comparable to that of commercial Pt/C. More attractively, it has good stabilities both in rotating disk electrode and single cell tests, which provides a large practical application potential in the replacement of Pt catalyst as the ORR electrocatalyst in fuel cells.


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