Core Parts
A PEM electrolyser is more than just a “cell”—it’s a system made up of:
1) Stack (the Electrochemical Core)
- Membrane (proton-conducting separator)
- Catalyst layers (drive the anode/cathode reactions)
- Electrodes/current collectors
- Bipolar plates / flow fields (distribute water and remove gases)
SENZA’s own technical articles describe the basic flow: water to plates/flow channels, reactions at the membrane interface, electrons through the circuit, protons through the membrane, and hydrogen formation at the cathode.
2) Balance of Plant (BOP — the Supporting Equipment)
- Power supply / DC conversion
- Water tank & pump (stable feed)
- Gas/water separation (reduce moisture carryover)
- Controls & safety devices (sensors, interlocks, alarms)
SENZA’s SZPE-300 listing is a good example of how these supporting items are often packaged alongside the stack.
Why BOP Matters as Much as the Stack
Many real-world issues—unstable output, low purity, poor reliability—come from water handling, gas separation, electrical supply quality, or operating outside rated limits, rather than the membrane itself. This is also why serious techno-economic and manufacturing analyses treat stack cost and BOP cost separately.