How a Fuel Cell Humidifier Controls Air Moisture with a Smart Valve

This patent describes a fuel cell humidifier that uses two humidifying spaces and a controllable valve to precisely adjust the moisture content of incoming air before it reaches the fuel cell stack, improving efficiency and durability.

What it covers

This humidifier prepares incoming air, called inflow gas, for a fuel cell by adding moisture. It features a body with two separate humidifying spaces, a first and a second, each containing special membranes (humidifying membranes) that allow water vapor to pass through. Exhaust gas from the fuel cell, which is naturally humid, flows around these membranes to transfer moisture to the drier inflow gas. A key component is a first valve installed in a 'passing space' (Claim 1). This valve can direct the inflow gas either through the second humidifying space, bypass the second humidifying space entirely, or split the flow so some goes through and some bypasses. By controlling this valve, the system can select the exact path for the inflow gas, allowing for fine-tuned humidification based on the fuel cell's needs (Claim 1). For example, if the fuel cell needs more humid air, the valve can direct all inflow gas through both humidifying spaces.

What it doesn't cover

• —Does not cover humidifiers that lack a second, distinct humidifying space that can be selectively bypassed by a valve.
• —Does not cover systems where the inflow gas always passes through the same humidification path without an adjustable valve.
• —Does not cover humidifiers that only use a single humidifying membrane or space for all incoming air.
• —Does not cover humidification methods that do not use exhaust gas from the fuel cell stack as the moisture source.
• —Does not cover humidifiers where the valve cannot split the inflow gas into both humidified and non-humidified streams simultaneously.

The clever bit

The clever part is the use of a single, controllable valve to dynamically choose or mix the humidification paths for the incoming air. This allows the system to precisely adjust the moisture level, either by sending all air through a more intense humidification path, bypassing it, or blending the two, all within a compact design.

Why it matters

Fuel cells need precisely humidified air to work efficiently and last longer. If the air is too dry, the fuel cell membranes can dry out and degrade; if it's too wet, water can flood the system. This patent from Hyundai Motor Co. offers a way to dynamically control humidification, which is crucial for optimizing fuel cell performance across different operating conditions, like varying temperatures or power demands. This precise control helps improve the lifespan and reliability of fuel cell vehicles.

Real-world examples

• 1.Hyundai NEXO fuel cell electric vehicle
• 2.Toyota Mirai fuel cell electric vehicle
• 3.Honda Clarity Fuel Cell
• 4.Stationary fuel cell power generators
• 5.Fuel cell buses and heavy-duty trucks