Fuel cell system for operation at pressures below the pressure of the surrounding environment and method of operation thereof

Abstract

In the present fuel cell systems, fuel cell stacks operate on a fuel stream having a pressure that is below the pressure of the surrounding environment, for example below atmospheric pressure. In the event of a leak, the fuel stream will not escape to the surrounding atmosphere, but rather gases from the surrounding environment will leak into the fuel stream. The fuel stream generally cannot exit the fuel cell stack during normal operation. The fuel cell stack may be periodically purged by increasing the pressure of the fuel stream above the pressure of the surrounding environment and by permitting exit through the fuel stream outlet. A monitoring device can be employed to determine when to purge the fuel cell stack.

Dependencies are inferred from the claim text.