How a Fuel Cell Humidifier Adjusts Air Moisture with a Bypass

This patent describes a fuel cell humidifier that uses a special bypass path to precisely control how much moisture is added to dry air, improving fuel cell performance.

What it covers

The patent describes a humidifier for a fuel cell (Claim 1). It includes a housing with a moist air supply port and a moist air discharge port. Inside, a humidifying membrane allows dry air to flow along its interior. The key feature is a "bypass flow path" (Claim 1) formed in the housing. This path allows a portion of the moist air to flow directly from the supply port to the discharge port without passing through the humidifying membrane. By changing the cross-sectional area of this bypass path (Claim 2), the humidifier can adjust the amount of humidification and the pressure difference across the device. For example, a controller can decrease the bypass area by moving a blocking member downward when the fuel cell needs more humidity (Claim 8), forcing more moist air through the membrane.

What it doesn't cover

• —Humidifiers that do not include a bypass flow path specifically for moist air.
• —Humidifiers where the bypass path is not used to adjust humidification or differential pressure based on operating conditions.
• —Humidifiers that do not specifically use a humidifying membrane for dry air flow.
• —Systems where the cross-sectional area of the bypass flow path cannot be changed selectively (Claim 2).
• —Humidifiers not designed for integration with a fuel cell stack.
• —Humidifiers that lack a controller to dynamically adjust the bypass based on humidity (Claim 6).

The clever bit

The clever part is using a bypass path for *moist air* to continuously flow around the humidifying membrane, allowing for dynamic adjustment of humidification and differential pressure based on the fuel cell's operating needs. This offers a way to fine-tune performance without completely redesigning the core humidification process.

Why it matters

Fuel cells require precise humidity levels to operate efficiently and prevent damage to their membranes. Too little moisture can dry out the membrane, reducing performance, while too much can flood the cell. This patent's method of dynamically adjusting humidification and differential pressure allows fuel cells to maintain optimal conditions, leading to better energy efficiency and longer operational life across various environmental and load conditions.

Real-world examples

• 1.Hydrogen fuel cell vehicles like the Hyundai NEXO
• 2.Stationary fuel cell power generators for buildings
• 3.Portable fuel cell devices for backup power