Polymer electrolyte fuel cell

• US 20060251944A1
• Filed: 04/19/2006
• Published: 11/09/2006
• Est. Priority Date: 03/26/2002
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kobayashi, Susumu, Takeguchi, Shinsuke, Kusakabe, Hiroki, Hatoh, Kazuhito, Kanbara, Teruhisa, Ohara, Hideo, Hase, Nobuhiro
• Granted Patent: US 8,012,646 B2
• Time in Patent Office: Days
• US Class Current: 429/431
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8807 Gas diffusion layers
• CPC Class Codes: H01M 4/8835 Screen printing
• CPC Class Codes: H01M 4/92 Metals of platinum group H01M4/94 , H01M4/9058 take precedence
• CPC Class Codes: H01M 4/96 Carbon-based electrodes
• CPC Class Codes: H01M 8/0202 Collectors; Separators, e.g. bipolar separators; Interconnectors
• CPC Class Codes: H01M 8/0258 characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
• CPC Class Codes: H01M 8/026 characterised by grooves, e.g. their pitch or depth
• 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 8/0271 Sealing or supporting means around electrodes, matrices or membranes
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: H01M 8/2457 with both reactants being gaseous or vaporised
• CPC Class Codes: H01M 8/247 Arrangements for tightening a stack, for accommodation of a stack in a tank or for assembling different tanks
• CPC Class Codes: H01M 8/2483 characterised by internal manifolds
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The durability of a polymer electrolyte fuel cell is very significantly improved by using a tightening pressure of about 2 to 4 kgf/cm² of area of electrode; or a tightening pressure of about 4 to 8 kgf/cm² of contact area between electrode and separator plate; or by selecting a value not exceeding about 1.5 mS/cm² for the short-circuit conductivity attributed to the DC resistance component in each unit cell; or by selecting a value not exceeding about 3 mA/cm² for the hydrogen leak current per area of electrode of each MEA. Further, in a method of manufacturing or an inspection method for a polymer electrolyte fuel cell stack, fuel cells having high durability can be efficiently manufactured by removing such MEAs or unit cells using such MEAs or such cell stacks having short-circuit conductivity values and/or hydrogen leak current values exceeding predetermined values, respectively.

Claims

1. A polymer electrolyte fuel cell comprising a cell stack having a plurality of unit cells tightened in a stacking direction of the stack, each unit cell comprising:

an electrolyte membrane-electrode assembly comprising a hydrogen ion conductive polymer electrolyte membrane and first and second electrodes respectively placed on opposite major surfaces of the electrolyte membrane, each of the electrodes comprising a gas diffusion layer and a catalyst layer;

a first electrically conductive separator plate contacting the first electrode and having a gas flow channel for supplying and exhausting a fuel gas to and from the first electrode; and

a second electrically conductive separator plate contacting the second electrode and having a gas flow channel for supplying and exhausting an oxidant gas to and from the second electrode, wherein the electrolyte membrane-electrode assembly has a short-circuit conductivity of not greater than about 1.5 mS/cm².

2. A polymer electrolyte fuel cell comprising a cell stack having a plurality of unit cells tightened in a stacking direction of the stack, each unit cell comprising:

an electrolyte membrane-electrode assembly comprising a hydrogen ion conductive polymer electrolyte membrane and first and second electrodes respectively placed on opposite major surfaces of the electrolyte membrane, each of the electrodes comprising a gas diffusion layer and a catalyst layer;

a first electrically conductive separator plate contacting the first electrode and having a gas flow channel for supplying and exhausting a fuel gas to and from the first electrode; and

a second electrically conductive separator plate contacting the second electrode and having a gas flow channel for supplying and exhausting an oxidant gas to and from the second electrode, wherein each of the unit cells comprising the electrolyte membrane-electrode assembly has a hydrogen leak current of not greater than about 3 mA/cm².