Thermal control of fuel cell for improved cold start

Abstract

Improvements in startup time for an electrochemical fuel cell system from freezing and sub-freezing temperatures are obtained by utilizing an insulated fuel cell stack in combination with an thermal control subsystem. Temperature of the insulated electrochemical fuel cell stack, as well as temperature of the ambient environment, are monitored and a heating fluid is heated by thermal transfer with the environment under appropriate thermal conditions. The heated fluid is then passed to the insulated fuel cell in order to increase the temperature of the same, typically to a temperature at or near the temperature of the ambient environment. In this manner, ambient heat from the environment is utilized to increase the temperature of the insulated fuel cell stack, thus improving conditions for subsequent cold start of the insulated fuel cell stack.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention generally relates to a thermal control system for an electrochemical fuel cell, as well as a method for improving thermal conditions for cold start of an insulated fuel cell stack. [0003] 2. Description of the Related Art [0004] Electrochemical fuel cells convert reactants, namely fuel and oxidant fluid streams, to generate electric power and reaction products. Electrochemical fuel cells employ an electrolyte disposed between two electrodes, namely a cathode and an anode. The electrodes each comprise an electrocatalyst disposed at the interface between the electrolyte and the electrodes to induce the desired electrochemical reactions. The location of the electrocatalyst generally defines the electrochemically active area. [0005] Polymer electrolyte membrane (PEM) fuel cells generally employ a membrane electrode assembly (MEA) consisting of an ion-exchange membrane disposed between two electrode...

AI Technical Summary

Benefits of technology

[0012] In brief, a thermal control subsystem is disclosed for an electrochemical fuel cell system, particularly with regard to improving thermal conditions for cold start of an insulated fuel cell stack. A disadvantage of insulting the fuel cell stack is that it is also insulated from increasing temperature as the ambient temperature rises. Thus, if the insulated fuel cell stack is exposed to freezing temperatures for a prolonged period of time, it will take longer for the insulated fuel cell stack to warm as the ambient temperature increases.

Problems solved by technology

A disadvantage of insulting the fuel cell stack is that it is also insulated from increasing temperature as the ambient temperature rises.

Thus, if the insulated fuel cell stack is exposed to freezing temperatures for a prolonged period of time, it will take longer for the insulated fuel cell stack to warm as the ambient temperature increases.

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