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Temperature-based Fuel Cell Freeze Protection Via Electric Heater

IP.com Disclosure Number: IPCOM000028929D
Publication Date: 2004-Jun-08
Document File: 1 page(s) / 28K

Publishing Venue

The IP.com Prior Art Database

Abstract

Fuel cell stack operation requires humidification with deionized water. After a fuel cell system is stopped and allowed to cool, water vapor condenses inside the fuel cell. If this water is not removed from the fuel cell system, damage to the fuel cell system components may occur if the water freezes. Existing methods of solving this problem require the removal of water from the fuel cell system's components. This is accomplished by blowing dry air through the fuel cell system (stack and related components) using an on-board electric air compressor. This process consumes energy and requires additional valves, microcontrollers, and their associated control methods to route the air through specified components. Additionally, this method can excessively dry out the internal membranes of the fuel cell stack, which can result in reduced fuel cell stack life.

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Temperature-based Fuel Cell Freeze Protection Via Electric Heater

Fuel cell stack operation requires humidification with deionized water. After a fuel cell system is stopped and allowed to cool, water vapor condenses inside the fuel cell. If this water is not removed from the fuel cell system, damage to the fuel cell system components may occur if the water freezes.  Existing methods of solving this problem require the removal of water from the fuel cell system's components. This is accomplished by blowing dry air through the fuel cell system (stack and related components) using an on-board electric air compressor. This process consumes energy and requires additional valves, microcontrollers, and their associated control methods to route the air through specified components. Additionally, this method can excessively dry out the internal membranes of the fuel cell stack, which can result in reduced fuel cell stack life.

A new method uses a temperature sensor or thermostat to monitor a temperature(s) and initiate the process of maintaining the desired components' temperature above a specified temperature. This process improves fuel cell stack durability, since the heating procedure does not occur on every shutdown of the fuel cell system, nor does it blow air through the stack thereby drying its membranes.

This method, as shown in the figure below, utilizes a temperature sensor or thermostat (#2) with the ability to provide an external control signal that indicates that a user-selectable temperature set point has been reached. This control signal enables a low voltage power relay's (#3) coil that closes the relay's contacts thus providing...