Thin-ply Conductive Interleaving for Health Monitoring of COPVs, Topic 10d

Fuel-cell electric vehicles utilizing hydrogen stored in composite overwrapped pressure vessels (COPVs) have unique safety risks. Hydrogen is an extremely volatile/explosive gas. Modern Hydrogen distribution and vehicle systems are targeting 700 bar storage pressure (>10,000 psi). At these high pressures, automotive-sized COPVs have a very high energy density, presenting a significant hazard. Tank failure can be catastrophic to the driver, passengers and public and must be prevented through effective design followed by consistent health monitoring in operation. Composite Technology Development, Inc. (CTD) will develop a pressure vessel/tank health monitoring technology consisting of fully embedded, in-situ electrode layers in tank overwrap composite. These electrodes will enable resistance-based monitoring of the tank health. As demonstrated repeatedly by many researchers, resistance measurements of composites have shown correlation to matrix microcracking, delamination, and various forms of composite laminate failure. In the proposed effort, CTD seeks to develop the materials and processes for interleaving multiple thin conductive plies through the thickness of filament wound tank walls. These layers form electrodes within the tank wall and enable resistance measurements of the overwrap composite to be readily acquired to monitor tank health over time. The proposed technology is a relatively simple, lower-cost, and easily implementable approach in modern vehicle computer systems. The overarching goal of the Phase I effort will be to evaluate the feasibility of the proposed approach for structural health monitoring (SHM) of composite tanks through an intensive material, coupon-level, and tank-level study. The three key stages of the proposed work plan include: 1) material development/ evaluation, 2) coupon-level testing (strength and stiffness), and 3) tank-level testing. It is anticipated that CTD will evaluate and refine the SHM approach/system at each of these stages. CTD will develop a complete prototype monitoring system (hardware/software) and methodology (processing and algorithms) as part of Phase I and will demonstrate its effectiveness on a small scale carbon fiber composite filament wound pressure vessel. The culmination of Phase I will result in a point-of-departure system design to be readied for commercialization in Phase II.The entry point for this technology will likely be in the automotive hydrogen fuel cell market where hydrogen vehicles are taking to the road. Beyond the automotive industry, the proposed health monitoring technology has the potential to be an early warning system for any fiber-reinforced composite tank wall or composite laminate for that matter. Composite structures such as aircraft skins or spacecraft composite panels may be monitored with this same system. . Some anticipated public benefits include much safer, reliable energy, transport and travel ways. Furthermore, the technology has the potential to reduce the cost of vehicles by reducing or eliminating the tendency for engineering over-design of COPVs.