PEM Technology
PEM Technology
Proton exchange membrane (PEM) fuel cells operate at relatively low temperatures, offer quick start-up times and require only hydrogen fuel and oxygen from the air to operate. Protonex’ patented design and manufacturing processes for PEM systems provide significant competitive advantages compared to competing solutions. Protonex fuel cell stacks utilize a unique mould-in-place, seating approach which provides much greater repeatability and robustness, and are driven by simple balance-of-plant subsystems based on commercially available, proven components.
Depending on the system size and application, hydrogen fuel for Protonex PEM systems would be supplied from one of the following sources:
- Compressed hydrogen
- Hydrogen stored in metal hydride cylinders
- Chemical hydrides
- Reformed methanol
The Fuel Cell System
The core of a fuel cell system is the fuel cell stack, which is created by stacking bipolar plates (with reactant flow fields) next to membrane electrode assemblies that consist of an electrolyte (membrane) and two catalyst-coated, porous electrodes (anode and cathode). Fuel cell systems also contain a number of pumps, valves, electronics and other specialty components (balance of plant) that make up the rest of the system, including fuel supply, cooling and power management.
Fuel Cell Operation
In the fuel cell system, hydrogen is fed to the anode side of the fuel cell stack where a platinum catalyst separates the hyrdogen’s negatively charged electrons from positively charged ions (protons). The protons then move through the membrane to the cathode and combine with oxygen from the air and electrons, to produce water and heat. The electrons from the anode side cannot pass through the membrane and as a result are forced around the membrane through an external electrical load before returning to the cathode side of the cell. The resultant flow of electrons is a useful electrical current.
The Protonex Solution
Protonex systems are based on the proprietary technology for designing and manufacturing proton exchange membrane (PEM) fuel stacks. While fueling and reliability remain issues on the path to widespread commercial success, the foremost hurdle facing fuel cell developers is the high cost of production. Protonex offers innovative designs and proprietary manufacturing processes for volume production and is therefore able to produce reliable, high performance fuel cell stacks at low costs.
Protonex System Design and Integration
Protonex’ expertise encompasses the design and manufacture of complete fuel cell systems as well as fuel cell stacks. Advanced stacks are only part of the technical challenge in the commercial-scale manufacture of fuel cell systems. Selection, design, assembly and integration of balance of plant components and fuel subsystems greatly affect critical system parameters, including size, weight, performance, reliability, durability and cost of the complete power systems. Balance of plant components and fuel typically account for one half to two-thirds of the weight of the total fuel cell system, and Protonex has optimized this portion by establishing beneficial relationships with well-known suppliers to obtain quality off-the-shelf components at low cost. This careful selection of subsystems and components has allowed Protonex to develop and demonstrate a system manufacturing approach based on modular design and assembly of balance of plant components.
Traditional Stack Manufacturing versus Protonex Proprietary Stack Manufacturing
