In this thesis, the treatments of MEA and the special structures
within carbon fiber bunch unipolar plates on the performance of PEMFC
are studied. At first, the factors affecting on the water content within
MEA will be studied. A passive HFC stack usually exposes in the ambient
no matter that it works or not. However, the ambient is far from saturated.
The water within MEA will vaporize continuously. Especially, if the stack
is shutdown for a long period, there is no water generation in the cathode
and then the membrane will be short in water. If it occurs, the
conductivity of H+ will decrease greatly, and the electrode of MEA is also
possible to separate from its membrane. This separation will make the
performance of the stack an unrecovered decay.
On the other hand, in order to improve the performance of a
air-breathing HFC, the inner structure within cathode carbon fiber bunch
unipolar plates is modified. The structure of the unipolar plates is
modified in the following three aspects: 1. Increasing soft end height of
carbon fiber bunch, 2. Increasing the number of silver-coated wires in
carbon fiber bunch, 3. Cutting several serrated slots on the soft end of
carbon fiber bunch.
In the MEA treatment, firstly, a MEA is boiled in 80oC, 0.5M H2SO4
solution and then boiled in 80oC DI water for an hour, respectively. When
the single-cell HFC operates in hydrogen inlet pressure 0.1 bar,
air-breathing, and room temperature, experimental results display that the
power density of this HFC with the aforementioned treatments and the
special structure of unipolar plates can reach a value about 185mW/cm2.
This value is about 130% higher than that of the untreated MEA and
about 50% higher than that of the treatment of MEA only immersed in DI
water.
In addition, the comparison of the performance of HFC between
with carbon fiber bunch unipolar plates and with graphite unipolar plates
are also studied. The experimental result displays that the performance of
HFC with the carbon fiber bunch unipolar plates is superior to that with
graphite unipolar plates, especially the fuel cell operating under low gas
inlet pressure.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0906110-175216 |
| Date | 06 September 2010 |
| Creators | Lai, Cian-jyun |
| Contributors | Chung-Fu Liu, Long-Jeng Chen, Ming-San Lee, Peng-sheng Wei |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0906110-175216 |
| Rights | not_available, Copyright information available at source archive |
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