Surface modification of carbon fiber phenolic bipolar plate for the HT-PEMFC with nano-carbon black and carbon felts

Abstract

The high temperature proton exchange membrane fuel cell (HT-PEMFC) operating from 120 degrees C to 220 degrees C is able to overcome many technical issues related to the low-temperature PEMFC (LT-PEMFC), such as their complex water/thermal management to prevent flooding/drying out of the membrane and their low tolerance to carbon monoxide. In a PEMFC stack, the bipolar plates are a major component, contributing 50% of the total cost and 80% of the total weight. In this study, a composite bipolar plate was developed using resole type phenolic and continuous carbon fiber to improve the high-temperature performance (similar to 220 degrees C) for use in HT-PEMFC applications. To improve the mechanical and electrical properties, the nano-size carbon black was mixed with phenolic resin. A pre-cure process using hot rolling was developed to achieve partial wetting of the carbon fiber felt on the carbon/phenol composite bipolar plate surface. The randomly oriented carbon fiber felt was co-cure bonded with the pre-cure process to modify the surface of the composite bipolar plates by exposing the bare carbon fibers on the outer surface, which reduced the ASR (areal specific resistance). The developed composite bipolar plate satisfied the DOE technical targets.