HIFI™
Technology
As industrial hydrogen production scales, the performance of electrolysis systems increasingly depends on what happens inside the cell stack—where water becomes gas, heat accumulates, and materials face constant mechanical and electrochemical stress.
Exion Hydrogen’s HIFI™ (Hydrogen Integrated Flow Improvement) technology was developed to address these challenges at their source. Born from years of high-fidelity simulation, advanced modeling, and rigorous testing, HIFI™ redefines how water and gas move through a pressurized electrolyzer, enabling more stable operation, higher efficiency, and longer stack lifetimes.
First introduced in the HyGGe™ 500P pressurized PEM electrolyzer and engineered for future use across both PEM and alkaline platforms, HIFI™ embodies our commitment to designing electrolyzers that deliver uncompromised performance—today and for the decades ahead.
Hydrogen Integrated Flow Improvement (HIFI™)
HIFI™ technology—Hydrogen Integrated Flow Improvement—is Exion Hydrogen’s proprietary solution for optimizing gas–liquid flow and thermal behavior inside pressurized cell stacks. It tackles a key electrolysis challenge: stable water and gas distribution under high current densities and pressure.
By refining internal flow patterns, HIFI™ creates uniform current and temperature profiles, resulting in higher efficiency, longer stack lifetime and improved reliability for industrial hydrogen production.
Developed through four years of modelling, simulation and validation, HIFI™ offers more homogeneous flow, better heat evacuation and lower mechanical stress—raising performance standards for both PEM and alkaline electrolysis.
HIFI™ debuts in the HyGGe™ 500P pressurized PEM electrolyzer and serves as the core platform technology for all future Exion Hydrogen stack designs.
The Challenge: Stable Flow Under Pressure
Every water electrolyzer must manage the complex two-phase flow of liquid water and evolving gas under high current densities and pressure. Poor distribution creates hot spots, dry-out or flooding—leading to faster wear, membrane degradation and lower efficiency.
Conventional, fuel-cell-inspired channel designs work at low pressure but become inefficient in high-throughput electrolysis, where uneven flow destabilizes thermal and electrical balance across the stack.
Exion Hydrogen took a different approach. Using advanced CFD simulations, 3D flow visualization and extensive testing, our engineers redesigned PEM cell hydraulics to stabilize two-phase flow across very large active areas—up to 6.5 mm between bipolar plates, compared to less than 0.6 mm in typical compact stacks.
HIFI™ solves the distribution challenge by refining internal geometry and precisely managing gas–water flow, ensuring homogeneous ratios across the full electrode surface. Applied in either PEM or alkaline systems, this delivers better current uniformity, steadier temperature profiles and a more consistent electrochemical interface—key to long-term industrial-scale reliability and efficiency.
This engineering shift forms the foundation of the performance leap enabled by HIFI™.
The Solution: Hydrogen Integrated Flow Improvement
At its core, HIFI™ is about intelligent fluid dynamics. It integrates a set of design and process innovations that together enhance performance, safety, and lifetime in industrial electrolysis stacks:
By reshaping the flow field geometry and optimizing gas evacuation pathways, HIFI™ achieves:
- Optimized Gas–Water Distribution – Achieves 2–5× higher water/gas ratio compared with benchmark designs, maintaining ideal hydration and stability.
- Enhanced Thermal Management – Improves heat evacuation by ~20%, mitigating temperature stress during high-load operation.
- Uniform Current Density – Balances electrochemical activity across the full active area, extending MEA and separator lifespan.
- Reduced Idle-Mode Stress – Limits residual gas and pressure fluctuation during transients, improving cycling behavior.
- 30 barg Pressurized Reliability – Maintains safe, balanced operation across both PEM and alkaline stacks with direct pressurized hydrogen output.
These improvements directly translate into longer lifetime, reduced degradation, and lower total cost of ownership (TCO) for Exion Hydrogen’s customers.
Cross-Platform Relevance
While first implemented within the HyGGe™ 500P PEM system, HIFI™ was conceived from the outset as technology-agnostic. Its flow optimization principles and heat-management architecture apply equally to pressurized alkaline stacks, where gas evolution and electrolyte circulation impose similar engineering challenges.
This shared foundation enables Exion Hydrogen to transfer R&D learnings between both electrolysis types, accelerating design maturity and ensuring consistent performance across the company’s dual-technology portfolio.
Engineering for Longevity
HIFI™ is more than a flow improvement—it is a reliability-first design philosophy built on smart engineering and high-performance materials.
Each stack uses precision-engineered bipolar plates, advanced protective coatings and uniform compression control, ensuring mechanical robustness and electrochemical stability under dynamic industrial loads.
In the HyGGe™ 500P PEM cell stack, titanium bipolar plates and noble-metal-coated components provide an optimal balance of cost-efficiency and long-term durability. These materials offer strong corrosion resistance in both oxidizing and reducing environments, while precision assembly maintains uniform compression across the MEAs—essential for consistent performance in a 2.5 MW-class stack.
By minimizing localized stress, every HIFI™ cell is built to withstand industrial cycling, high load dynamics and pressurized operation—while maintaining hydrogen purity of 4.8 or better.
Performance and Integration
The HyGGe™ 500P marks the first deployment of HIFI™ in the field, offering:
- 500 Nm³/h hydrogen output from a single stack operating at 30 barg.
- 2.5 MW nominal power per module, containerized for fast deployment.
- Direct connection to pipelines, storage, or mobility refueling systems.
This configuration enables simplified plant design, fewer compression stages, and greater overall system efficiency—a vital step toward scalable, bankable hydrogen production.
Future HIFI™-enhanced alkaline systems will leverage the same principles of optimized flow, balanced pressure, and consistent thermal management, enabling Exion Hydrogen to deliver a unified engineering philosophy across both technologies.
Built on Proven Research and Testing
HIFI™ is the result of multi-year R&D collaboration between Exion Hydrogen’s Belgian engineering center and Polish manufacturing plant, combining advanced CFD modeling, materials science, and real-world endurance testing.
From prototype validation to full-scale industrial stack assembly, every iteration was rigorously evaluated for hydraulic stability, electrical homogeneity, mechanical strength, and thermal equilibrium under pressurized operation—culminating in a design built to perform, last, and scale.
The innovation stems from Exion Hydrogen’s broader principle: No Compromises.
“We don’t differentiate by cutting corners, but by engineering longevity into every stack—from alkaline to PEM.”
Roel De Mayer – CEO Exion Hydrogen
Benefits at a Glance
| Performance Metric | Benefit |
| Gas-Water Ratio | Gas-Water Ratio 2–5× higher hydration stability |
| Thermal Management | 20% more efficient heat evacuation |
| Stack Lifetime | Reduced degradation, longer intervals |
| Pressure Operation | 30 barg direct output |
| Integration | Lower CAPEX and OPEX through minimal downstream compression |
| Reliability | Uniform current and flow distribution, applicable to both PEM and alkaline |
Future outlook
HIFI™ technology represents a cornerstone in Exion Hydrogen’s dual-technology roadmap—bridging pressurized alkaline and PEM electrolysis into one unified portfolio.
By combining engineering depth, digital simulation, and manufacturing precision, Exion Hydrogen delivers on its mission: to build electrolyzers that last longer, perform better, and scale smarter.
Discover how HIFI™ technology redefines PEM performance. Contact our experts.
