Electrode-integrated bipolar plate structure for multi-cells in vanadium redox flow batteries

A major challenge hindering the progress of vanadium redox flow batteries (VRFBs) is the reduction of cell resistance. These batteries operate by assembling various components, such as electrodes, bipolar plates, and membranes. Minimizing the contact resistance between bipolar plates and electrodes is crucial to prevent a nonuniform charge distribution. Integrating electrodes and bipolar plates provides a definitive approach to eliminate contact resistance. This study aims to reduce the cell resistance by reducing the interfacial contact resistance among components in the stack. This can be achieved by fabricating an electrode-integrated bipolar plate (BP) composite structure from a single carbon felt (CF). The electrode-integrated BP developed in this study showed 28% reduction in the total resistance and a 175% increment in mechanical property. Acid aging and gas permeability test verified the durability of the electrode-integrated BP with zero gas permeability. Finally, a two-cell charge/discharge test verified that the developed structure exhibited a 6.3% enhancement in energy efficiency. Therefore, the developed structure is a promising alternative to conventional BP and CF electrode assemblies.