Wax elements as passive control devices in fuel cell power systems

摘要

A fuel cell system that employs one or more wax elements to provide passive control. In one embodiment, a wax element device is positioned within a coolant stream pipe. The wax element device includes a wax element positioned within a container. An electrically conductive rod is positioned within the wax element and extends out of the pipe. As the wax element expands and contracts in response to temperature changes in the cooling fluid, the rod moves up and down to make various electrical contacts and control the various devices, such a coolant pump and a coolant fan. In another embodiment, the rod extends into a cathode exhaust pipe of the fuel cell system, and is coupled to a back-pressure valve therein. As the temperature of the cooling fluid changes, the wax element expands and contracts to control the position of the back-pressure valve.

主权项

1. A fuel cell system comprising:
a fuel cell stack including a stack of fuel cells; and a cooling system for cooling the fuel cell stack, said cooling system including a cooling line delivering cooled cooling fluid to the stack and removing heated cooling fluid from the stack, said cooling system further including a wax element device positioned within the cooling line, said wax element device including a container mounted to the cooling line, a wax element positioned within the container and a rod mounted to the wax element and extending out of the cooling line, said wax element expanding and contracting in response to temperature changes to the cooling fluid, said rod moving in response to the expansion and contraction of the wax element to provide control of at least one fuel cell system device.