Improving the electrical performance of a carbon fiber reinforced polymer bipolar plate using a resin squeeze-out preprocess

Carbon fiber reinforced polymer (CFRP) is attracting attention as a bipolar plate (BP) material for proton-exchange membrane fuel cells (PEMFCs) due to its high specific stiffness, strength and chemical resistance. However, the low electrical conductivity of CFRP acts as an obstacle in its application, and various studies have been conducted to improve its areal specific resistance (ASR). In particular, the electrical performance of channel-shaped BPs has been dramatically reduced because the resin flow of CFRP was blocked by the groove shape. In this study, the electrical conductivity of a channel-shaped CFRP BP was improved by a preprocess of resin squeezing out. Resin squeeze-out conditions were determined based on the resin viscosity and degree of cure (DoC). Using the resin squeeze-out process, extra resin was removed, and the carbon fiber volume fraction increased by inducing proper resin flow. The mechanical properties and electrical performance of the CFRP BPs were evaluated according to a 2025 Department of Energy (DOE) technical target. Through the optimal resin squeeze-out process, the electrical and mechanical properties of the channel-shaped CFRP BP were improved to satisfy the 2025 DOE target.