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122 || AWSAR Awarded Popular Science Stories - 2019
Polymer electrolyte membrane fuel cell
(Dimensions not to scale)
“So far so good,” Pankaj replied promptly. I continued, “Well, in order to obtain some useful amount of power, we need to stack multiple unit cells using bipolar plates (BPP). The BPPs acts as interconnect between adjacent cells to carry electric current from anode of one cell to the cathode of the adjacent cell. In this way, an entire unit of PEMFC is a layered framework consisting of a BPP, an anode, a polymer electrolyte, a cathode and again a BPP. An arrangement of several such assemblies is known as a fuel cell stack.”
“But, hang on!” he interrupted. “From where do you supply the fuels, hydrogen and oxygen to the cell?” Pankaj made a worthy observation.
“Remember, when I told that we investigate the performance of one of the most critical components of PEMFCs. As a matter of fact, apart from interconnecting the adjacent cells to carry electric current, the BPPs
also carry fuels to the respective
electrodes, specifically
hydrogen gas to anode and
oxygen gas to cathode and
distributes them uniformly via
flow channels. Apart from that,
they also facilitate exhaust
water management and provide
structural stability as well as
mechanical strength to the
PEMFC stack assembly,” I
responded.
“Indeed, it serves multiple functions. An all-rounder in your fuel cell team,” quipped the cricket-crazy Pankaj. “What materials are used for making BPPs?” he continued.
“That is precisely where my research contributes. As I mentioned earlier, metals are generally used as BPP materials. However, since BPPs have to perform a variety of functions, appropriate material selection obviously becomes a crucial parameter. Apart from being electrically conductive, it should be thermally conductive as well to dissipate the extra heat and be gas impermeable to avoid leakages. Most importantly, it must be resistant to corrosion in both hydrogen and oxygen environments at normal PEMFC operating temperature of 70 – 80 °C.
“The objective of my research is to improve the properties of metallic BPPs to enhance the durability and performance of PEMFCs. We develop electrically conductive and corrosion resistant BPP materials and study their performance in simulated operating conditions of PEMFCs,” I replied.
“So, how is your progress? Have you developed any such BPP
materials?” he enquired.
“Well, till now we have
got some promising results at the laboratory level. Further studies are being carried out to check their compatibility. I will surely let you know if there is any interesting development,” I promised.
“Your work seems interesting, but I can’t claim to understand everything you said. I will read more about PEMFCs and get back to you with more doubts,” he responded filled with curiosity.
the BPPs also carry fuels to the respective electrodes, specifically hydrogen gas to anode and oxygen gas to cathode and distributes them uniformly via flow channels. Apart from that, they also facilitate exhaust water management and provide structural stability as well as mechanical strength to the PEMFC stack assembly
all mines,” I said.
“Sure, the pleasure will be