Bipolar plates manufacturing

Design and construct a pilot-scale production line to demonstrate high volume, low-cost bipolar plate manufacturing... 

These difficult and sometimes conflicting specifications which must be met, along with the fact that modem electrodes require very little catalytic platinum, mean that the bipolar plate is the most expensive part of a modern fuel cell. In conclusion, we should note that although a broad range of bipolar plate manufacturing techniques exist, none of them fully meet the criteria set above. There is much development still to be done in this area before a new industry standard is established. 

Innovative Approaches of Composite Bipolar Plates Manufacturing... 

But besides GrafTech, many more bipolar plate manufacturers offer composite bipolar plates (produced by different methods and various materials) for use in PEM fuel cells as shown in Table 6.4. 

Before describing some of the most promising and widely used processes, we should note one feature of bipolar plate manufacture that is common to many - that the plate is... 

Abstract This chapter describes the behavior and stability of metallic bipolar plates in polymer electrolyte fuel ceU application. Fundamental aspects of metallic bipolar plate materials in relation to suitability, performance and cell degradation in polymer electrolyte fuel cells are presented. Comparing their intrinsic functional properties with those of carbon composite bipolar plates, we discuss different degradation modes and causes. Furthermore, the influence and possible improvement of the materials used in bipolar plate manufacturing are described. 

There has been an accelerated interest in polymer electrolyte fuel cells within the last few years, which has led to improvements in both cost and performance. Development has reached the point where motive power applications appear achievable at an acceptable cost for commercial markets. Noticeable accomplishments in the technology, which have been published, have been made at Ballard Power Systems. PEFC operation at ambient pressure has been validated for over 25,000 hours with a six-cell stack without forced air flow, humidification, or active cooling (17). Complete fuel cell systems have been demonstrated for a number of transportation applications including public transit buses and passenger automobiles. Recent development has focused on cost reduction and high volume manufacture for the catalyst, membranes, and bipolar plates. 

Although it is difficult to determine the quantitative requirements of plate and plate materials appropriately for various fuel cells and different applications in a development phase, such a target would be helpful to direct the development effort and make necessary trade-offs. The cascaded performance requirement targets in 2010 and 2015 for bipolar plates of fuel cells in transportation applications were set by the U.S. DoE (Department of Energy) according to functions of the plate mentioned before and overall requirements of performance, reliability, manufacturability, and cost of a stack, as shown in Table 5.1 [7]. The technical target in the DoE s multiyear research, development, and demonstration plan has been popularly and worldwide... 

The manufacturing cost of a PEM fuel-cell stack includes the individual costs of the membrane, the electrodes, the platinum catalyst, the bipolar plates, the... 

The committee believes that PEM electrolysis is subject to the same basic cost reduction drivers as those for fuel cells. Cost breakthroughs in (1) catalyst formulation and loading, (2) bipolar plate/flow field, (3) membrane expense and durability, (4) volume manufacturing of subsystems and modules by third parties, (5) overall design simplifications, and (6) scale economies (within limits) all promise to lower... 

Component manufacture (gas diffusion electrodes, membranes, bipolar plates) ... 

Conventional hydrochloric acid electrolyzers consist of 30-36 individual cells connected in series (bipolar arrangement). The cells are formed from vertical electrode plates manufactured from graphite, between which there are diaphragms (for instance made from PVC fabric, distance to the plates ca. 6 mm). The feed with hydrochloric acid (22 wt%, identical for anode and cathode compartment) and the removal of the gases produced take place according to the filter press principle (see Chapter 2). Chlorine leaves the cell with the anolyte, hydrogen with the catholyte. 

Cooper, J.S. Design analysis of PEMFC bipolar plates considering stack manufacturing and environment impact. J. Power Sources 2004, 129 (2), 152-169. 

Phase II focuses upon process development to result in a pilot production line capable of producing 300 bipolar plates per hour. Our goal is a complete functional pilot line, including all relevant quality assurance, failure mode and effects analysis, and statistical manufacturing characterization processes. This will be completed by transferring the most promising mass-production technique to laiger-scale and continuous equipment operation in a dedicated production line. 

Preliminary work completed in this project includes laboratory and equipment setup and installation, and preliminary rounds of material optimization and process development. Full size bipolar plate prototypes have been produced with full double-sided flow patterns, demonstrating the potential of the manufacturing process. Process and material development has resulted in the characterization of material properties under a variety of composition levels. Material properties meeting or exceeding DOE targets have been measured, and bipolar plates, both machined and pattern-embossed, have been submitted to UTC Fuel Cells for in and out of cell testing. Phase I work will... 

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