Type V Vessel-Aided Electrochemical Compression for Ultra-High Pressure Electrolysis

Current electrolysis technologies typically produce hydrogen most efficiently and safely between 1-30 bar. Unfortunately, there are a variety of higher pressure hydrogen needs between 200-700 bar, including heavy-duty vehicle fuel and ammonia production. There is significant investment focused on reducing the cost of green hydrogen production at low pressures, but this will not solve the challenges facing higher pressure hydrogen needs, which are dominated by expensive, energy-intensive, and high maintenance mechanical compressors. The National Renewable Energy Laboratory estimates that CSD costs would add $2.70 kg to the cost of 700 bar hydrogen fuel in a mature market (15% FCEV penetration). Hydrogen fuel needs to cost between $3-$4 kg to be cost-competitive with fossil fuels, making CSD costs a critical hurdle to enabling hydrogen fuel cell, zero emission medium and heavy-duty vehicles. If hydrogen fuels can become cost competitive with fossil fuels for medium and heavy-duty vehicles, there is an opportunity to reduce U.S. carbon emissions by 435 metric tons of CO2 and fuel imports by $13.65B gallons annually. To solve the hydrogen compression challenge, there is the opportunity to use electrochemical compression within the electrolysis stack to eliminate or reduce the amount of mechanical compression needed. In the past, this approach has been plagued by mechanical stability and hydrogen crossover challenges. pH Matter has solved the hydrogen crossover challenges with our patented, hybrid liquid alkaline-AEM electrolysis cell, which has 30x less crossover than a state-of-the-art PEM electrolyzer. In this project, we propose to solve the mechanical stability challenges by integrating our electrolysis stack in a Type V, liner free composite cylinder to produce hydrogen 250+ bar with electrochemical compression. We estimate producing hydrogen between 250-800 bar can reduce the cost of 700 bar hydrogen fuel by $0.50-$2.00 kg. Teams at pH Matter, Infinite Composites, and WHA International will partner together to solve the challenges facing this approach. A key goal of this project will be to demonstrate hydrogen production at 250+ bar using less than 50 kW-h kg in a carbon fiber vessel capable of 550+ bar pressure. Specific objectives that will be achieved to accomplish the overall goal include: 1. Optimize the PHM electrolysis cell design for operation at 250+ bar, including safety analysis of the design; optimize layer thicknesses and H2-O2 pressure differential 2. Ensure that a cell stack will survive the Infinite Composite manufacturing process, including how to mount the stack, and strategies to survive the curing steps and hydrostatic tests 3. Demonstrate a 5-kW electrolysis stack in a composite carbon fiber tank at 250+ bar metric (550 bar stretch goal) with energy use below 50 kWh kg for hydrogen production We propose a budget of $500,000 to achieve these development goals over a period of 24 months. This proposal is for a combined phase I phase II grant with a go-no go milestone after task 2 consisting of 3-cell stack performance at 250-bar demonstrates less than 50 kWh kg after simulated manufacturing process. The project end goal will be a demonstration of a 30-cell, 5-kW electrolyzer, contained in a Type V vessel, that can produce 250 bar+ hydrogen at less than 50 kWh kg. PHM is currently developing a 2-kW, 250-bar reversible fuel cell stack for a NASA Tipping Point project. PHM is also developing a 5-kW, 30-bar hydrogen oxygen generation system for a commercial project with Shell (through its subsidiary Power to Hydrogen). Infinite has previously completed grant and development projects focused on Type V vessel design and construction for NSF, NASA, Army, AFWERX, SpaceX, and Blue Origin, among others. Infinite has 40+ high-pressure units operating successfully in the field. WHA International has provided hydrogen and oxygen safety expertise for 30+ years to various industries.