JP2010113959A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain degradation of energy efficiency and retain temperature of an end-part cell, in a fuel cell stack. <P>SOLUTION: The fuel cell stack 100 made by laminating a plurality of unit cells 10, is provided with heat transmission plates 20a, 20b arranged in contact with the end part cell arranged at the end part in a lamination direction of the unit cell 10, and a water storage tanks 50a, 50b each connected with the heat transmission plate 20a, 20b, respectively, and storing product water HW of high temperature generated at the time of power generation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell stack.

  A fuel cell that generates power by an electrochemical reaction between a fuel gas and an oxidant gas has attracted attention as an energy source. In a fuel cell stack in which a plurality of such fuel cells (single cells) are stacked, water (product water) is generated by the cathode reaction at the cathode of each single cell during power generation. And in a fuel cell stack, the temperature of a single cell (hereinafter referred to as an end cell) arranged at the end in the stacking direction of the single cells becomes lower than that of the single cell arranged at the center due to heat dissipation. For this reason, in the end cells, the saturated water vapor pressure is reduced, the generated water is likely to condense, and uneven flooding and gas distribution are likely to occur.

  Therefore, conventionally, for example, by providing an electric heater for heating the end cells in the fuel cell stack or circulating cooling water having a temperature higher than the outside air to the fuel cell stack, the temperature of the end cells can be kept warm. Was done.

JP 2006-179404 A JP 2005-100701 A

  However, according to the conventional technique, electric energy is required for heat retention of the end cell, that is, heating of the end cell with an electric heater and circulation of cooling water, resulting in a decrease in energy efficiency.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to keep the end cells warm while suppressing a decrease in energy efficiency in the fuel cell stack.

  The present invention can be realized as the following forms or application examples in order to solve at least a part of the above-described problems.

  [Application Example 1] A fuel cell stack in which a plurality of single cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and the end cells arranged at the end in the stacking direction of the single cells A fuel cell stack comprising: a heat transfer plate disposed in contact with the heat transfer plate; and a water storage tank that is connected to the heat transfer plate and stores generated water generated during power generation.

  In the fuel cell stack of Application Example 1, high-temperature generated water generated during power generation is stored in a water storage tank, and the heat of this generated water is conducted to the end cells via a heat transfer plate connected to the water storage tank. Thus, the end cell can be heated. For this reason, no electrical energy is required to keep the end cells warm. Therefore, the fuel cell stack of Application Example 1 can keep the end cells warm while suppressing a decrease in energy efficiency.

Hereinafter, embodiments of the present invention will be described based on examples.
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell stack 100 as an embodiment of the present invention.

  The fuel cell stack 100 has a stack structure in which a plurality of single cells 10 that generate power by an electrochemical reaction between hydrogen and oxygen are stacked. Each unit cell 10 generally has a configuration in which a membrane electrode assembly in which an anode and a cathode are joined to both surfaces of an electrolyte membrane having proton conductivity is sandwiched between separators. In this example, a solid polymer membrane such as Nafion (registered trademark) is used as the electrolyte membrane.

  The fuel cell stack 100 is configured by stacking an end plate 40a, an insulating plate 30a, a heat transfer plate 20a, a plurality of single cells 10, a heat transfer plate 20b, an insulating plate 30b, and an end plate 40b in this order from one end. . Connected to the heat transfer plates 20a and 20b are storage tanks 50a and 50b, respectively, for storing the generated water generated by the electrochemical reaction during the power generation in the fuel cell stack 100 and discharged together with the anode off-gas and cathode off-gas. Has been.

  Hydrogen as fuel gas is supplied to the anode of each single cell 10 of the fuel cell stack 100 via a hydrogen supply pipe (not shown). The anode off gas discharged from the anode of each single cell 10 is introduced into the water storage tank 50 a through the pipe 60. And the high temperature produced water HW contained in the anode off gas is separated and stored in the water storage tank 50a. The anode off gas from which the produced water HW has been separated is exhausted via the pipe 61.

  Compressed air compressed by a compressor is supplied as an oxidant gas containing oxygen to the cathode of each unit cell 10 of the fuel cell stack 100 via an air supply pipe (not shown). Cathode off-gas discharged from the cathode of each single cell 10 is introduced into the water storage tank 50 b via the pipe 62. Then, the high-temperature generated water HW contained in the cathode off gas is separated and stored in the water storage tank 50b. The cathode off gas from which the produced water HW has been separated is exhausted via the pipe 63.

  In the fuel cell stack 100 of the present embodiment, the heat of the high-temperature generated water HW stored in the water storage tanks 50a and 50b is passed through the heat transfer plates 20a and 20b, respectively, in the stacking direction ends of the plurality of single cells 10. The end cells can be heated by conducting to the end cells located in the section. For this reason, no electrical energy is required to keep the end cells warm. Therefore, according to the fuel cell stack 100 described above, it is possible to keep the end cells warm while suppressing a decrease in energy efficiency.

It is explanatory drawing which shows schematic structure of the fuel cell stack 100 as one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Fuel cell stack 10 ... Single cell 20a, 20b ... Heat-transfer plate 30a, 30b ... Insulation plate 40a, 40b ... End plate 50a, 50b ... Water storage tank 60, 61, 62, 63 ... Piping HW ... Generated water

Claims (1)

A fuel cell stack formed by laminating a plurality of single cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas,
A heat transfer plate disposed in contact with an end cell disposed at an end of the single cell in the stacking direction;
A water storage tank that is connected to the heat transfer plate and stores generated water generated during power generation;
A fuel cell stack comprising:

Images