[Enthalpy]

Hello dear friends!

Here's an electrolyser design, not as compact as with proton exchange membranes, but with decent power density, gas separation and ease of construction and cooling. As usual, I didn't check if it's already done.

The inclination and shape of the insulators use buoyancy to separate the gases. This permits the short and broad ionic current to flow perpendicularly to the long and closely packed electrodes. Sketches attached.

The design is meant first for flexible printed circuits, but for instance a ceramic is possible:

• The insulator foil is strong and flexible, often 25µm thick. Polyimide resists nothing, but polyester resists acids.
• The conductors are usually 35µm copper etched to shape. Thicker is possible. I'd leave copper but add a thin protective precious metal.
• Manufacturers etch, cut, fold to any shape. I'd stabilize the shape by the thick current bars that join the electrodes.
• The current bars must be insulated where they cross opposite electrodes. I'd have a protective metal layer elsewhere, including at the solder points.
• Half-tubes collect the bubbles on the sketch, but many other options exist.
• The liquid can flow gently through the vat and pass by a heat exchanger.

An an example, the grooves can be 6mm wide and deep, with 8mm half-period between the electrodes and 10mm period between the insulators. Each electrode can exchange 40A/m; 70µm copper need a bar every half metre. Every dm³ contains 6.25*10 electrode pairs that cumulate 250A, every m³ 250kA. Not far from what proton exchange membranes achieve.

A computer motherboard provides about 1V and 100A to the Cpu: re-commission some.

Marc Schaefer, aka Enthalpy