JP2011086565A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of suppressing shorting of a fuel cell stack in a fuel cell system. <P>SOLUTION: The fuel cell system includes a fuel cell stack which generates power by electrochemical reaction using fuel gas, an insulating first route member through which the water generated by the electrochemical reaction of the fuel cell stack and the gas exhausted from the fuel cell stack pass, a conductive second route member which is connected to the first route member, and an insulating protruding member which is arranged at the connection point between the first route member and the second route member to protrude farther inside beyond an inner wall of the first route member and the inner wall of the second route member. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell system.

  In recent years, vehicles equipped with fuel cell systems are being put into practical use. In general, a fuel cell system includes a fuel cell stack that generates power by an electrochemical reaction between hydrogen and oxygen, as well as generated water generated by the electrochemical reaction of the fuel cell stack and discharged hydrogen discharged from the fuel cell stack. It has a gas-liquid separation device that separates the gas, a circulation pump for supplying the exhausted hydrogen gas separated from the generated water to the fuel cell stack again, and the like.

  The circulation pump in the fuel cell system is often formed of a metal member, while the gas-liquid separator is often formed of a member such as a resin for weight reduction. Conventionally, as a technique related to a fuel cell system, for example, one disclosed in Patent Document 1 is known.

  In many cases of a fuel cell system, a fuel cell stack and an insulating gas-liquid separator are connected, and a member constituting a circulation pump path is provided downstream of a member constituting the gas-liquid separator path. It is connected. This conductive circulation pump may be connected to a ground such as a vehicle frame.

  In such a fuel cell system, when a high-voltage portion of the fuel cell stack (for example, a flow path in the separator constituting the fuel cell stack) and the circulation pump are conducted through generated water, the fuel cell stack is short-circuited. There was a problem such as.

  Such a problem is not limited to the relationship between the gas-liquid separator of the fuel cell system and the circulation pump connected to the gas-liquid separator, but generally, an insulating path member through which the generated water and the exhaust gas pass. And a conductive path member connected to the path member is a common problem.

JP 2008-84590 A JP 2005-11797 A

  The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a technique capable of suppressing a short circuit of a fuel cell stack in a fuel cell system.

  In order to solve at least a part of the problems described above, the present invention can take the following forms or application examples.

[Application Example 1]
A fuel cell system,
A fuel cell stack that generates electricity by an electrochemical reaction using fuel gas; and
An insulating first path member through which the generated water generated by the electrochemical reaction of the fuel cell stack and the exhaust gas discharged from the fuel cell stack passes;
A conductive second path member connected to the first path member;
An insulating protrusion that is disposed at a connection location between the first path member and the second path member and protrudes inward from the inner wall of the first path member and the inner wall of the second path member. And a fuel cell system.

  According to the fuel cell system of Application Example 1, since the continuity of generated water can be divided by the protruding member, it is possible to suppress a short circuit of the fuel cell stack via the generated water.

[Application Example 2]
A fuel cell system according to Application Example 1,
The fuel cell system, wherein the protruding member is sandwiched between the first path member and the second path member.

  According to the fuel cell system of Application Example 2, the protruding member can be reliably fixed.

[Application Example 3]
A fuel cell system according to Application Example 2,
The projecting member is a fuel cell system configured integrally with a seal member for maintaining airtightness between the first path member and the second path member.

  According to the fuel cell system of Application Example 3, since the protruding member and the seal member are integrally formed, the number of parts can be reduced.

[Application Example 4]
The fuel cell system according to any one of Application Examples 1 to 3,
The protruding member is a fuel cell system formed of an elastic body.

  According to the fuel cell system of Application Example 4, it is possible to reduce the pressure loss inside the path member.

[Application Example 5]
The fuel cell system according to any one of Application Examples 1 to 4,
A fuel cell system in which a tip portion of the protruding member is formed in a pleat shape.

  According to the fuel cell system of Application Example 5, the continuity of the generated water can be effectively divided.

[Application Example 6]
The fuel cell system according to any one of Application Examples 1 to 5,
The protruding member is a fuel cell system in which the exhaust gas is formed outside a curve drawn by a flow line flowing from the first path member toward the second path member.

  The generated water tends to flow along the path member in the outer portion of the curve drawn by the streamline. Therefore, according to the fuel cell system of Application Example 5, the continuity of the generated water can be effectively divided.

[Application Example 7]
The fuel cell system according to any one of Application Examples 1 to 6,
The exhaust gas is an exhaust hydrogen gas exhausted from the fuel cell stack,
The first path member is a member included in a gas-liquid separator that separates the generated water and the exhaust hydrogen gas.

[Application Example 8]
The fuel cell system according to Application Example 7, wherein the second path member is a member included in a pump that sucks up the exhaust hydrogen gas from the gas-liquid separator.

  Note that the present invention can be realized in various modes. For example, it can be realized in the form of a method for suppressing the occurrence of a short circuit in the fuel cell system.

It is explanatory drawing which shows roughly the structure of the fuel cell system as one Example of this invention. 2 is an explanatory diagram schematically showing a fuel cell stack 100 and peripheral devices connected to the fuel cell stack 100. FIG. It is explanatory drawing which expands and shows the connection location of the gas-liquid separator 230 and the hydrogen circulation pump 250. FIG. It is explanatory drawing which shows an example of a layout in case the fuel cell stack 100 is mounted in a vehicle. It is explanatory drawing which shows the protrusion member 240a in the modification 1. It is explanatory drawing which shows the protrusion member 240b in the modification 2. It is explanatory drawing which shows the protrusion member 240c in the modification 3.

  Next, embodiments of the present invention will be described based on examples.

A. Example:
FIG. 1 is an explanatory diagram schematically showing the configuration of a fuel cell system as an embodiment of the present invention. The fuel cell system 1000 is a system that generates power using an electrochemical reaction between hydrogen and oxygen, and includes a fuel cell stack 100, an air supply system 150, and a fuel supply system 200. In this embodiment, the fuel cell system 1000 for a fuel cell vehicle is used as an example. However, the present invention can also be applied to other fuel cell systems such as a stationary fuel cell system.

  The fuel cell stack 100 includes a stacked body 110 in which a plurality of cells (not shown) are stacked, and two end plates EP that sandwich the stacked body 110. The cell is formed by stacking a separator, a hydrogen electrode (hereinafter referred to as “anode”), an electrolyte membrane, an oxygen electrode (hereinafter referred to as “cathode”), and a separator in this order. For example, the cell generates power by an electrochemical reaction between hydrogen supplied through a groove provided in the separator and oxygen contained in the air. In this embodiment, a polymer electrolyte fuel cell is used.

  The air supply system 150 is a system for supplying air to the fuel cell stack 100, and includes a filter 152, a compressor 154, and an air supply path 156 that connects these devices. Air taken in from the outside through the filter 152 is compressed by the compressor 154 and supplied to each cathode of the plurality of cells constituting the fuel cell stack 100. Air that has passed through the fuel cell stack 100 is discharged to the outside.

  The fuel supply system 200 is a system for supplying hydrogen gas as fuel gas to the fuel cell stack 100, and includes a hydrogen tank 202, a pressure reducing valve 206, and a fuel supply path 208 connecting these devices. It is out. The hydrogen gas stored in the hydrogen tank 202 is depressurized to a predetermined pressure by the pressure reducing valve 206 and then supplied to each anode of a plurality of cells constituting the fuel cell stack 100.

  The fuel supply system 200 further supplies a gas that has passed through the fuel cell stack 100 and discharged from the fuel cell stack 210 (hereinafter also referred to as “exhaust hydrogen gas”) to the fuel cell stack 100 again. The liquid separator 230, the hydrogen circulation pump 250, the circulation path 270, and the purge valve 280 are included.

  The gas-liquid separation device 230 is a device that separates generated water and exhaust hydrogen gas generated by an electrochemical reaction in the fuel cell stack 100. The exhaust hydrogen gas separated from the generated water by the gas-liquid separator 230 is introduced into the circulation path 270 by the hydrogen circulation pump 250 and supplied to the fuel cell stack 100 again. On the other hand, the produced water separated from the discharged hydrogen gas by the gas-liquid separator 230 is discharged to the outside through the purge valve 280. The hydrogen circulation pump 250 is usually formed of a conductive member such as metal (stainless steel in this embodiment).

  FIG. 2 is an explanatory diagram schematically showing the fuel cell stack 100 and peripheral devices connected to the fuel cell stack 100. In FIG. 2, the horizontal direction when the fuel cell is installed is indicated by an arrow L, and the vertical direction is indicated by an arrow H. The same applies to the drawings described below. The fuel cell stack 100 is supported by support members 102 and 104. A gas-liquid separator 230 and a hydrogen circulation pump 250 are disposed on the end plate EP side of the fuel cell stack 100. The circulation path 270 connected to the hydrogen circulation pump 250 is connected to the end plate EP, and the exhaust hydrogen gas that has passed through the gas-liquid separator 230 is supplied again to the fuel cell stack 100 by the hydrogen circulation pump 250.

  FIG. 3A is an explanatory diagram showing an enlarged connection location between the gas-liquid separator 230 and the hydrogen circulation pump 250. FIG. 3B is an explanatory diagram showing the inside of the gas-liquid separator 230 from the direction of the arrow Y in FIG. In FIG. 3A, as part of the gas-liquid separator 230, a generated water storage unit 232 for storing the generated water separated from the discharged hydrogen gas and a path for the discharged hydrogen gas separated from the generated water are shown. A cylindrical path portion 234 extending in a substantially vertical direction and a flange portion 236 for connecting to the hydrogen circulation pump 250 are shown. The gas-liquid separator 230 is formed of an insulating member such as a resin (in this embodiment, a nylon resin).

  Further, in FIG. 3A, as a part of the hydrogen circulation pump 250, a flange portion 252 for connecting to the flange portion 236 of the gas-liquid separation device 230, and a path for exhausted hydrogen gas in a substantially vertical direction. An elongated cylindrical path 254 is shown.

  The flange portion 236 of the gas-liquid separator 230 is fastened to the flange portion 252 of the hydrogen circulation pump 250 by fastening bolts 130. An annular groove portion 256 is formed in the flange portion 252 of the hydrogen circulation pump 250, and an annular seal member 255 is disposed in the groove portion 256. This seal member 255 is a so-called O-ring, and ensures airtightness between the path portion 112 of the gas-liquid separator 230 and the path portion 254 of the hydrogen circulation pump 250. The seal member 255 is formed of a material having gas impermeability, elasticity, and heat resistance, for example, an elastic member such as rubber. Specifically, ethylene / propylene rubber, silicon rubber, butyl rubber, acrylic rubber, natural rubber, fluorine rubber, ethylene / propylene rubber, styrene elastomer, fluorine elastomer and the like are used. In this embodiment, the seal member 255 is formed of ethylene / propylene rubber.

  The discharged hydrogen gas separated from the generated water passes through the generated water storage unit 232 by the suction action of the hydrogen circulation pump 250 and is further introduced in a substantially vertical direction through the path unit 234 and the path unit 254. This flow of exhausted hydrogen gas is shown as a streamline SL in FIG.

  In the present embodiment, an insulating protruding member that protrudes inward from the inner wall of the path part 234 and the path part 254 is connected to the path part 234 of the gas-liquid separator 230 and the path part 254 of the hydrogen circulation pump 250. 240 is arranged. The generated water that has traveled along the wall surface of the path portion 234 by the suction action of the hydrogen circulation pump 250 is blocked by the protruding member 240, and is prevented from traveling along the wall surface of the path portion 254, and its continuity is also disrupted. That is, the generated water stored in the generated water storage unit 232 is transmitted through the wall surface of the path unit 234 by the suction action of the hydrogen circulation pump 250, and the path unit 254 of the hydrogen circulation pump 250 and the path unit 234 of the gas-liquid separation device 230 It can be suppressed that the continuity is maintained while maintaining the continuity. As a result, according to the present embodiment, the fuel cell stack 100 can be prevented from conducting with the hydrogen circulation pump 250 via the generated water.

  In addition, the hydrogen circulation pump 250 formed of a conductive member may be connected to a ground (for example, a vehicle frame) directly or via another member. Even in such a case, the insulating portion projecting inward from the inner walls of the path portion 234 and the path portion 254 is connected to the path portion 234 of the gas-liquid separator 230 and the path portion 254 of the hydrogen circulation pump 250. Since the protruding member 240 is disposed, the fuel cell stack 100 can be prevented from being short-circuited through the generated water.

  The protruding member 240 is preferably sandwiched between the path portion 234 of the gas-liquid separator 230 and the path portion 254 of the hydrogen circulation pump 250 as in this embodiment. In this way, the protruding member 240 can be reliably fixed so as to be able to resist the flow of discharged hydrogen gas or generated water.

  Further, as in this embodiment, the protruding member 240 is preferably configured integrally with the seal member 255. In this way, the number of parts can be reduced. The protruding member 240 is preferably formed of an elastic member similar to the seal member 255. In this way, the pressure loss inside the path portions 234 and 254 can be reduced.

  Furthermore, as shown in FIG. 3B, it is preferable that the tip end portion of the protruding member 240 is formed in a pleat shape. By doing so, the draining performance at the tip of the protruding member 240 is improved, and the continuity of the generated water can be effectively divided.

  Further, as in the present embodiment, it is preferable that the protruding member 240 is provided on the outer portion of the curved line drawn by the streamline SL on the inner wall of the path portion 234. The reason for this will be described. The generated water wound up by the hydrogen circulation pump 250 often travels along the inner wall of the path portion 234 in the outer portion of the curve drawn by the streamline SL. Therefore, if the protruding member 240 is provided on the outer side of the curve drawn by the streamline SL in the inner wall of the path portion 234, a short circuit of the fuel cell stack 100 due to the generated water can be effectively suppressed. However, the projecting member 240 may be formed on the inner side of the curved line drawn by the streamline SL in the inner wall of the path portion 234, and is formed so as to go around the radial direction of the inner wall of the path portion 234. May be. Even in this case, a short circuit of the fuel cell stack 100 can be suppressed.

  FIG. 4 is an explanatory diagram showing an example of a layout when the fuel cell stack 100 is mounted on a vehicle. As shown in FIG. 4, the fuel cell stack 100 can be disposed, for example, in an underfloor portion of a vehicle seat 400. However, the fuel cell stack 100 may be disposed in the hood of the vehicle or in an underfloor portion other than the seat.

  In addition, according to the present Example, since the short circuit by the generated water of the fuel cell stack 100 can be suppressed, the length of the path part 234 and the path part 254 can be shortened. Therefore, the fuel cell system 1000 can be reduced in size and weight.

B. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

B1. Modification 1:
FIG. 5 is an explanatory view showing the protruding member 240a in the first modification. In the above embodiment, a plurality of protrusions are formed on the tip of the projecting member 240 and have a pleated shape. However, as shown in FIG. A single protrusion may be formed. Even in this case, it is possible to prevent the fuel cell stack 100 from being short-circuited through the generated water. That is, the number of protrusions at the tip of the protruding member 240 can be set to an arbitrary number as long as the continuity of generated water can be effectively divided.

B2. Modification 2:
FIG. 6 is an explanatory view showing the protruding member 240b in the second modification. In the above embodiment, a plurality of protrusions are formed on the tip of the projecting member 240 and have a pleated shape. However, as shown in FIG. The protrusion may not be formed. Even in this case, it is possible to prevent the fuel cell stack 100 from being short-circuited through the generated water. However, the continuity of the generated water can be effectively divided if the tip of the protruding member 240 is pleated as in the embodiment.

B3. Modification 3:
FIG. 7 is an explanatory view showing a protruding member 240c in the third modification. In the above-described embodiment, the protruding member 240 is formed integrally with the seal member 255. However, as shown in FIG. 7A, the protruding member 240c may be configured as a separate member from the seal member 255. . Even in this case, it is possible to prevent the fuel cell stack 100 from being short-circuited through the generated water.

B4. Modification 4:
The protruding member 240 may have a shape in which a tip end portion thereof is slanted downward. In this way, even if the hydrogen circulation pump 250 stops and the generated water flows in the vertically downward direction (reverses flow), the generated water flows in the vertically downward direction without accumulating in the upper part of the protruding member 240. become. That is, even if the generated water accumulated in the upper part of the protrusion 240 is frozen, the frozen generated water is sucked into the hydrogen circulation pump 250 and the occurrence of problems in the hydrogen circulation pump 250 can be suppressed. it can.

B5. Modification 5:
In the above-described embodiments and modifications, the connection portion between the gas-liquid separator 230 and the hydrogen circulation pump 250 has been described as an example. However, the present invention is an insulating first in which the generated water and the exhaust gas pass in the fuel cell system. The present invention can be applied to one path member and a conductive second path member connected to the first path member. For example, the second path member may be a conductive path member included in a pressure sensor or the like that detects the pressure of the exhaust gas.

DESCRIPTION OF SYMBOLS 100 ... Fuel cell stack 102 ... Support member 110 ... Laminate body 112 ... Path part 130 ... Fastening bolt 150 ... Air supply system 152 ... Filter 154 ... Compressor 156 ... Air supply path 200 ... Fuel supply system 202 ... Hydrogen tank 206 ... Pressure reducing valve DESCRIPTION OF SYMBOLS 208 ... Fuel supply path 210 ... Fuel cell stack 230 ... Gas-liquid separator 232 ... Generated water storage part 234 ... Path | route part 236 ... Flange part 240 ... Projection member 240a ... Projection member 240b ... Projection member 240c ... Projection member 250 ... Hydrogen circulation Pump 252 ... Flange part 254 ... Path part 255 ... Seal member 256 ... Groove part 270 ... Circulation path 280 ... Purge valve 400 ... Seat 1000 ... Fuel cell system SL ... Streamline EP ... End plate

Claims (8)

A fuel cell system,
A fuel cell stack that generates electricity by an electrochemical reaction using fuel gas; and
An insulating first path member through which the generated water generated by the electrochemical reaction of the fuel cell stack and the exhaust gas discharged from the fuel cell stack passes;
A conductive second path member connected to the first path member;
An insulating protrusion that is disposed at a connection location between the first path member and the second path member and protrudes inward from the inner wall of the first path member and the inner wall of the second path member. And a fuel cell system. The fuel cell system according to claim 1,
The fuel cell system, wherein the protruding member is sandwiched between the first path member and the second path member. The fuel cell system according to claim 2, wherein
The projecting member is a fuel cell system configured integrally with a seal member for maintaining airtightness between the first path member and the second path member. A fuel cell system according to any one of claims 1 to 3,
The protruding member is a fuel cell system formed of an elastic body. A fuel cell system according to any one of claims 1 to 4,
A fuel cell system in which a tip portion of the protruding member is formed in a pleat shape. A fuel cell system according to any one of claims 1 to 5,
The protruding member is a fuel cell system in which the exhaust gas is formed outside a curve drawn by a flow line flowing from the first path member toward the second path member. A fuel cell system according to any one of claims 1 to 6,
The exhaust gas is an exhaust hydrogen gas exhausted from the fuel cell stack,
The first path member is a member included in a gas-liquid separator that separates the generated water and the exhaust hydrogen gas. The fuel cell system according to claim 7, wherein the second path member is a member included in a pump that sucks up the exhaust hydrogen gas from the gas-liquid separator.

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