# US 7,745,063 B2 · Fuel cell stack

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- Number: US 7,745,063 B2
- Document ID: US7745063B2
- Status: Granted
- Kind: B2
- Application number: 11/099,627
- Filed: 2005-04-06
- Published: 2005-10-27
- Granted: 2010-06-29
- Earliest claimed: 2004-04-27
- Assignees: Panasonic Corporation
- Inventors: Takashi Akiyama; Kohji Yuasa; Hideyuki Ueda; Shinsuke Fukuda
- Web page: https://patentgrep.com/patent/US7745063B2

## CPC

- H01M 8/0265: the reactant or coolant channels having varying cross sections
- H01M 8/0245: in the form of layered or coated products
- H01M 8/0258: characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
- H01M 8/026: characterised by grooves, e.g. their pitch or depth
- H01M 8/0263: having meandering or serpentine paths
- H01M 8/0267: having heating or cooling means, e.g. heaters or coolant flow channels
- H01M 8/04291: Arrangements for managing water in solid electrolyte fuel cell systems (H01M8/04119 takes precedence)
- H01M 8/1007: with both reactants being gaseous or vaporised (H01M8/12 takes precedence)
- H01M 8/1011: Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
- H01M 8/1067: characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
- H01M 8/241: with solid or matrix-supported electrolytes
- H01M 8/2484: characterised by external manifolds
- H01M 4/8814: {Temporary supports, e.g. decal}
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

To prevent the flooding phenomenon at the cathode in a unit cell where the temperature is relatively low or the supply of air is small, a fuel cell stack includes at least three flat unit cells stacked with separators interposed therebetween, the unit cells comprising an anode, a cathode and an electrolyte membrane sandwiched therebetween, and having an oxidant channel formed on the surface of the separator adjacent to the cathode, and the anode and the cathode comprising a catalyst layer attached to the electrolyte membrane and a diffusion layer, wherein the cross-sectional area of the inlet side of the oxidant channel, the area of the cathode catalyst layer, the thickness of the electrolyte membrane or the amount of a water repellent contained in the combination of the cathode and the oxidant channel is the largest in at least one of the unit cells at the ends of the stack.

## Claims

### Claim 1

A fuel cell stack comprising at least three flat unit cells stacked with separators interposed therebetween,
said unit cell each comprising an anode, a cathode and an electrolyte membrane sandwiched between said anode and said cathode, and having an oxidant channel formed on the surface of said separator adjacent to said cathode, and
said anode and said cathode each comprising a catalyst layer attached to said electrolyte membrane and a diffusion layer,
wherein the total cross-sectional area of the inlet side of said oxidant channel is larger in both of the unit cells positioned at the ends of said stack relative to the rest of the stack.