Electrochemical fuel cell stack with humidification section located upstream from the electrochemically active section

• US 5,382,478 A
• Filed: 03/15/1994
• Issued: 01/17/1995
• Est. Priority Date: 11/03/1992
• Status: Expired due to Term

• Current Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Original Assignee: Ballard Power Systems Corporation (Superior Plus Corporation)
• Inventors: Chow, Clarence Y., Wozniczka, Boguslav M.
• Primary Examiner(s): SKAPARS, ANTHONY
• Application Number:
  US08/213,615
• Time in Patent Office: 308 Days
• Field of Search: 429/30, 429/34, 429/26, 429/12, 429/38, 429/39
• US Class Current: 429/414
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 8/0263 having meandering or serpentine paths
• CPC Class Codes: H01M 8/0267 having heating or cooling means, e.g. heaters or coolant flow channels
• CPC Class Codes: H01M 8/04029 Heat exchange using liquids
• CPC Class Codes: H01M 8/04097 with recycling of the reactants H01M8/04119, H01M8/04104 take precedence
• CPC Class Codes: H01M 8/04119 with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
• CPC Class Codes: H01M 8/04156 with product water removal
• CPC Class Codes: H01M 8/04231 Purging of the reactants
• CPC Class Codes: H01M 8/04291 Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised H01M8/12 takes precedence
• CPC Class Codes: H01M 8/242 comprising framed electrodes or intermediary frame-like gaskets H01M8/2425, H01M8/244 take precedence
• CPC Class Codes: H01M 8/2457 with both reactants being gaseous or vaporised
• CPC Class Codes: H01M 8/2483 characterised by internal manifolds
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An electrochemical fuel cell stack has a humidification section located upstream from the electrochemically active section. The inlet fuel and oxidant streams are introduced into the humidification section without first being directed through the electrochemically active section. The upstream location of the humidification section in the stack enables the number of manifold openings in the active section to be reduced, thereby increasing the area available for the electrochemical reaction.

Claims

1. An electrochemical fuel cell stack comprising an inlet fuel stream, an inlet oxidant stream, a humidification section and an electrochemically active section, said humidification section disposed upstream from said active section such that said inlet fuel stream and said inlet oxidant stream are introduced into said humidification section without first being directed through said active section.

2. The electrochemical fuel cell stack of claim 1 further comprising an outlet fuel stream and an outlet oxidant stream, wherein said outlet fuel stream and said outlet oxidant stream are both directed through said humidification section before being exhausted from the stack.

3. An electrochemical fuel cell stack comprising:

(A) a hydrogen-containing inlet fuel stream;

(B) an oxygen-containing inlet oxidant stream;

(C) an inlet coolant water stream;

(D) a humidification section comprising;

(1) a fuel humidification portion comprising a fuel humidification water supply and means for imparting water vapor from said fuel humidification water supply to said inlet fuel stream to produce a humidified fuel stream;

(2) an oxidant humidification portion comprising an oxidant humidification water supply and means for imparting water vapor from said oxidant humidification water supply to said inlet oxidant stream to produce a humidified oxidant stream;

(E) an electrochemically active section comprising;

(1) at least one fuel cell comprising;

(a) an anode having an inlet for directing said humidified fuel stream to the catalytically active portion of said anode;

(b) a cathode having an inlet for directing said humidified oxidant stream to the catalytically active portion of said cathode; and

(c) an ion exchange membrane interposed between said anode and said cathode;

(2) at least one coolant passage having an inlet for directing said inlet coolant water stream into thermal contact with said electrochemically active section to absorb heat generated within said active section and produce an outlet coolant water stream;

wherein said humidification section is located upstream from said electrochemically active section such that said inlet fuel stream and said inlet oxidant stream are introduced into said fuel humidification portion and said oxidant humidification portion, respectively, without first being directed through said electrochemically active section.

4. The electrochemical fuel cell stack of claim 3 wherein said anode further produces an outlet fuel stream and said cathode further produces an outlet oxidant stream, said outlet fuel stream and said outlet oxidant stream are both being directed through passages formed in said humidification section before said streams are exhausted from the stack.

5. The electrochemical fuel cell stack of claim 3 wherein said fuel humidification water supply and said oxidant humidification water supply are drawn from a common water supply.

6. The electrochemical fuel cell stack of claim 5 wherein at least a portion of said common water supply is drawn from the water formed electrochemically at said cathode.