JPH08339814A - Fuel cell - Google Patents

Abstract

PURPOSE: To provide a fuel cell which has a simple construction and can easily and accurately uniform the temperature of a power generation portion. CONSTITUTION: A fuel cell is provided with a fuel cell structure body 18 and a separator 20. The separator 20 is equipped with first gas pass 50b in which oxidizing agent gas flows to an air electrode 14, second gas pass 56b in which fuel gas flows to a hydrogen electrode 16 side, first and second cooling medium passes 50d, 56d which have same pass structures with those of the first and second gas passes 50b, 56b on front and back sides. In the first and second gas passes 50b, 56b, oxidizing agent gas and fuel gas flow from up in a gravity direction, while, in the first and second cooling medium passes 50d, 56d, the cooling medium flows in a reverse direction of the gravity direction. Thereby, heat exchange efficiency between the oxidizing agent gas and the fuel gas is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell provided with a fuel cell structure having an anode electrode and a cathode electrode opposed to each other with a solid polymer electrolyte membrane sandwiched therebetween, and a separator sandwiching the fuel cell structure. Regarding

[0002]

2. Description of the Related Art A fuel cell constructed by stacking a plurality of fuel cell structures in which an anode-side electrode and a cathode-side electrode are opposed to each other with a solid polymer electrolyte membrane sandwiched therebetween by a separator has been developed, and various fuel cells have been developed. It is being put to practical use.

In this type of fuel cell, heat is generated during the reaction between the fuel gas and the oxidant gas, and heat is generated due to contact resistance and the like, and it is necessary to cool the fuel cell structure. Therefore, for example, as disclosed in JP-A-5-144451, a fuel cell having a reaction gas / cooling medium flow structure is adopted.

As shown in FIG. 7, the fuel cell described above is provided with a fuel gas passage 4 and an oxidant gas passage 6 on both sides of the fuel cell structure 2, and is adjacent to the oxidant gas passage 6. The cooling medium passage 9 in the cooling plate 8 arranged as
Are formed. Fuel gas passage 4 and oxidant gas passage 6
Are formed substantially parallel to the cooling medium passage 9. The fuel gas and the oxidant gas flow in the fuel gas passage 4 and the oxidant gas passage 6 in the arrow direction, while the fuel flows in the cooling medium passage 9. The cooling medium is configured to flow in the same direction as the gas and the oxidant gas.

Further, in the above fuel cell, the cooling medium passage 9 which is substantially parallel to the fuel gas passage 4 and the oxidant gas passage 6 is used in place of the cooling medium passage 9 in the direction orthogonal to the fuel gas passage 4 and the oxidant gas passage 6. A structure including a cooling plate having a cooling medium passage formed therein is disclosed.

[0006]

However, in the fuel cell structure, the heat generated by the power generation reaction is usually exchanged with the gas (fuel gas and oxidant gas), and at the same time, the heat caused by the contact resistance is generated. Heat exchange with gas. Therefore, a temperature distribution is generated between the gas on the inlet side (upstream side) and the gas on the outlet side (downstream side), and the temperature of the gas on the outlet side rises. Therefore, it has been pointed out that in the structure in which the cooling medium flows in the same direction as the fuel gas and the oxidant gas, the gas temperature on the inlet side and the gas temperature on the outlet side cannot be made uniform.

Further, when the cooling medium is caused to flow in the direction orthogonal to the flow directions of the fuel gas and the oxidant gas, the temperature distribution of the gas becomes complicated and it is considerably difficult to make the gas temperature uniform as a whole. There is a problem of becoming.

The present invention solves this type of problem, and an object of the present invention is to provide a fuel cell having a simple structure and capable of easily and accurately equalizing the temperature of the power generation section.

[0009]

To achieve the above object, the present invention provides a fuel cell structure in which a cathode side electrode and an anode side electrode are provided opposite to each other with a solid polymer electrolyte membrane interposed therebetween.
A separator for sandwiching the fuel cell structure,
The separator includes first and second gas flow passages for flowing an oxidant gas and a fuel gas to the cathode-side electrode and the anode-side electrode, respectively, in parallel to each other and in the direction of gravity, and the first and / or second gas passages. A temperature control medium channel provided in the gas channel through a partition wall and having the same channel structure as the first and / or second gas channel, and the first and / or second channel The flow direction of the gas in the gas flow channel and the flow direction of the temperature control medium in the flow channel for temperature control medium are set to be opposite to each other.

[0010]

In the above fuel cell, the first gas passage for flowing the oxidant gas and / or the second gas passage for flowing the fuel gas are provided.
The gas flow path is provided with a flow path for a temperature control medium having the same flow path structure as these through a partition wall, and the flow direction of the oxidant gas and / or the fuel gas and the flow direction of the temperature control medium are They are set in opposite directions. For this reason,
For example, the oxidant gas flowing through the first gas flow path and the cooling medium flowing through the temperature control medium flow path will flow through the same flow path in the front and back in opposite directions, and the oxidant gas and the cooling medium The heat exchange efficiency is improved, and the temperature of the power generation part can be made uniform. Similarly, for example, by the fuel gas flowing through the second gas flow path and the cooling medium flowing through the temperature control medium flow path,
The temperature of the power generation part can be made uniform.

[0011]

The fuel cell according to the present invention will be described in detail below with reference to the accompanying drawings.

1 to 3, reference numeral 10 indicates
1 shows a fuel cell according to this example. This fuel cell 10
A fuel cell structure 18 in which an air electrode (cathode-side electrode) 14 and a hydrogen electrode (anode-side electrode) 16 are opposed to each other with the solid polymer electrolyte membrane 12 sandwiched between them, and a separator 20 sandwiching the fuel cell structure 18 are provided. Prepare The fuel cell structure 18 and the separator 20 include a pair of end plates 22a and 22b.
And it is fixed integrally by the tie rod 24.

On the upper side of the solid polymer electrolyte membrane 12 constituting the fuel cell structure 18, a cooling medium (temperature control medium) discharge hole 12a, an oxidant gas introduction hole 12b and a fuel gas introduction hole are formed. While the portion 12c is provided, a fuel gas discharge hole 12d, an oxidant gas discharge hole 12e, and a cooling medium introduction hole 12f are provided on the lower side thereof.

On both sides of the electrolyte membrane 12, the first and second layers are formed.
Gaskets 30, 32 are provided. First gasket 3
0 has a large opening 34 for accommodating the air electrode 14, and the second gasket 32 has a large opening 36 for accommodating the hydrogen electrode 16. On the upper side of the first and second gaskets 30, 32, the cooling medium discharge hole 30 is provided.
a, 32a, oxidant gas introduction holes 30b, 32b and fuel gas introduction holes 30c, 32c are provided,
On the lower side of these, the fuel gas discharge holes 30d, 32
d, oxidant gas discharge holes 30e and 32e, and cooling medium introduction holes 30f and 32f are provided.

The separator 20 is sandwiched between the first separator portion 40 that contacts the air electrode 14 side, the second separator portion 42 that contacts the hydrogen electrode 16 side, and the first and second separator portions 40, 42. And a partition plate 44.

The first separator section 40 includes a first manifold plate 46 and an oxidant gas rectifying plate (separator component) 50 that fits into a relatively large opening 48 formed in the first manifold plate 46. Have.

The first manifold plate 46 is a rectangular flat plate made of dense carbon, and has a cooling medium discharge hole 46a and an oxidant gas introduction hole 46b on the upper side thereof.
And a fuel gas introducing hole 46c are provided. On the lower side of the first manifold plate 46, the fuel gas discharge hole 46
d, an oxidant gas discharge hole 46e, and a cooling medium introduction hole 46f are provided.

The holes 46b and 46e communicate with the opening 48 through the notches 47a and 47b formed in one surface (on the side of the air electrode 14) of the first manifold plate 46, while the holes 46a and 46f are connected to each other. , Communicates with the opening 48 via notches 47c, 47d formed in the other surface of the first manifold plate 46 (see FIGS. 2 and 4).

The oxidant gas straightening plate 50 is made of carbon, stainless steel, or a corrosion resistant conductive metal such as nickel-based alloy such as Inconel (trademark), conductive rubber or conductive resin, and combinations thereof. Composed of materials. On one surface of the rectifying plate 50 for oxidant gas, a plurality of protrusions 50a that extend in the horizontal direction and are arranged in parallel and in a zigzag pattern are provided, and these protrusions 50a direct vertically. A meandering first gas flow path 50b is formed (see FIG. 4). Similarly, on the other surface of the rectifying plate 50 for oxidant gas, a plurality of protrusions 50c are provided in parallel with each other in the horizontal direction and in a staggered pattern, so that the same as the first gas flow path 50b. First having a flow channel structure
A cooling medium flow channel (temperature control medium flow channel) 50d is formed.

The second separator portion 42 has a second manifold plate 52 and a fuel gas rectifying plate 56 fitted in a relatively large opening 54 formed in the center of the second manifold plate 52. The second manifold plate 52 is configured similarly to the first manifold plate 46, and has a cooling medium discharge hole 52a, an oxidant gas introduction hole 52b, and a fuel gas introduction hole 52c on the upper side thereof. On the other hand, a fuel gas discharge hole 52d, an oxidant gas discharge hole 52e, and a cooling medium introduction hole 52f are provided on the lower side thereof.

The holes 52a and 52f communicate with the opening 54 through notches 58a and 58b formed in one surface (on the side of the first separator 40) of the second manifold plate 52, and the holes 52c and 52d. Is the second manifold plate 5
It communicates with the said opening part 54 via the notches 58c and 58d formed in the other 2 surface part (refer FIG. 2 and FIG. 5).

The fuel gas straightening plate 56 is made of a water-permeable carbon material. A second gas flow path 56b is formed on one surface of the fuel gas rectifying plate 56 by a plurality of protrusions 56a that extend in the horizontal direction, are parallel to each other, and are arranged in a staggered pattern. Similarly, on the other surface portion of the fuel gas rectifying plate 56, the second cooling medium flow path (via the plurality of protruding portions 56c that extend in the horizontal direction and are parallel to each other and arranged in a staggered manner) A temperature control medium flow path) 56d is formed. Second gas channel 56b and second cooling medium channel 56d
Have the same flow channel structure as each other and are set to flow directions opposite to each other (see FIG. 5).

As shown in FIG. 6, the opening cross-sectional area of the first gas flow channel 50b and the opening cross-sectional area of the first cooling medium flow channel 50d are the same as those of the second gas flow channel 56b and the second cooling medium. It is set to be larger than the opening cross-sectional area of the flow channel 56d.

The partition plate 44 has a plate shape formed of a dense carbon material, and has a cooling medium discharge hole 44a, an oxidant gas introduction hole 44b, and a fuel gas introduction on the upper side thereof. A hole 44c for use is provided. A fuel gas discharge hole 44d, an oxidant gas discharge hole 44e, and a cooling medium introduction hole 44f are provided on the lower side of the partition plate 44.

The operation of the fuel cell 10 thus constructed will be described below.

When the fuel gas (hydrogen gas) is supplied to the fuel cell 10, the fuel gas is supplied to the holes 46c of the first manifold plate 46, the holes 44c of the partition plate 44, and It is supplied to the hole portion 52c of the second manifold plate 52 that constitutes the second separator portion 42, and is introduced into the second gas flow passage 56b of the fuel gas rectifying plate 56 from the notch 58c of the hole portion 52c (Fig. 5). Therefore, the fuel gas flows in the direction of gravity so as to meander along the second gas flow path 56b, and is discharged from the notch 58d to the hole 52d.

When the oxidant gas is supplied to the fuel cell 10, the oxidant gas is supplied to the holes 46b of the first manifold plate 46, the holes 44b of the partition plate 44 and the holes 52b of the second manifold plate 52. While being supplied, it is introduced into the first gas flow path 50b of the rectifying plate 50 for oxidant gas via the notch 47a communicating with the hole 46b. Therefore, as shown in FIG. 4, the oxidant gas flows in the direction of gravity so as to meander along the first gas passage 50b and is discharged from the hole 46e. As a result, the fuel gas is supplied to the hydrogen electrode 16 constituting the fuel cell structure 18 and the oxidant gas is supplied to the air electrode 14.

On the other hand, the cooling medium supplied to the fuel cell 10 is water, methanol, or a mixed solution of water and methanol, and when this cooling medium is supplied to the hole 46f of the first manifold plate 46, A part is introduced from the notch 47d into the first cooling medium flow path 50d of the oxidant gas flow regulating plate 50. Therefore, as shown in FIG. 4, the cooling medium flows in the direction opposite to the gravity direction so as to meander along the first cooling medium flow path 50d of the oxidant gas flow regulating plate 50, and thus the first manifold plate. It is discharged to the hole 46a of 46.

Further, the hole portion 52 of the second manifold plate 52
A part of the cooling medium introduced into f is introduced into the second cooling medium passage 56d of the fuel gas rectifying plate 56 from the notch 58b. Therefore, as shown in FIG. 5, the cooling medium flows in the direction opposite to the gravity direction so as to meander along the second cooling medium flow path 56 d of the fuel gas flow-straightening plate 56, and the cooling medium of the second manifold plate 52 It is discharged to the hole 52a.

In this case, in the present embodiment, as shown in FIG. 4, the first gas flow passage for causing the oxidizing gas to meander in the direction of gravity on one surface of the rectifying plate 50 for oxidizing gas. 50b is provided, and the first gas flow path 50b is provided on the other surface of the rectifying plate 50 for oxidant gas.
The first cooling medium flow passage 50d is provided which has the same flow passage structure as the front and back sides and allows the cooling medium to flow in the direction opposite to the gravity direction.

That is, the oxidizing gas is used as the first gas flow path 5.
0b compared to the inlet side (hole portion 46b side), the outlet side (hole portion 46b)
The e side) has the highest temperature. Therefore, the hole 46f corresponding to the hole 46e side where the temperature of the oxidizing gas becomes high
By introducing the cooling medium from the side, the heat exchange efficiency between the cooling medium and the oxidizing gas is improved at once, and the oxidizing gas flows from the inlet side to the outlet side of the first gas flow path 50b. There is an effect that the temperature is surely adjusted to a state where there is no temperature difference as a whole, and the temperature of the power generation unit is easily equalized.

On the other hand, in the fuel gas straightening plate 56, similarly, as shown in FIG. 5, the fuel gas flowing in the direction of gravity along the second gas passage 56b and the second cooling medium passage 56.
The cooling medium flowing in the direction opposite to the gravity direction along d is
The same flow path on the front and back sides flows in opposite directions. Therefore, there is an advantage that the temperature difference between the inlet side and the outlet side of the fuel gas is reduced and the temperature of the power generation part is made uniform.

Further, in this embodiment, the first gas flow path 50
b and the opening area of the first cooling medium flow path 50d is the second
It is set to be larger than the opening cross-sectional areas of the gas passage 56b and the second cooling medium passage 56d. That is, since the fuel gas and the oxidant gas are composed of, for example, a reformed gas of methanol and air, a hydrogen gas and air, or a combination of hydrogen gas and oxygen gas, their viscosities are different. Therefore, when the fuel gas and the oxidant gas are caused to flow at the same flow rate with respect to the same gas channel cross-sectional area, a higher head pressure is generated on the oxidant gas side than on the fuel gas side. As a result, there arises a problem that the inter-electrode differential pressure is generated and the solid polymer electrolyte membrane 12 is damaged or the load of the oxidant gas supply source is increased.

Further, when the reformed gas and air are used as the fuel gas and the oxidant gas, a difference occurs in the flow rate reduction of the fuel gas and the air due to the fuel utilization rate and the air utilization rate. Is smaller than the decrease in the flow rate of the fuel gas.

As a result, the first gas passage 5 on the oxidant gas side
It is necessary to make the opening cross-sectional area of 0b larger than the opening cross-sectional area of the second gas passage 56b side of the fuel gas side.

Furthermore, on the side of the air electrode 14, the reaction product water may be condensed and condensed on the wall surface of the oxidant gas straightening plate 50. Therefore, the opening cross-sectional area of the first gas flow passage 50b is set to be larger than the opening cross-sectional area of the second gas flow passage 56b, so that the gas flow passage is blocked by dew condensation water, and the pulsating flow ( (For example, slag flow), the oxidant gas flows easily, and the gas exhaust efficiency is maintained.

In the present embodiment, the case where the cooling medium is used as the temperature control medium to uniformly cool the oxidant gas and the fuel gas has been described. On the contrary, the heating medium is used to perform the oxidation. It is also possible to heat the agent gas and the fuel gas to a uniform temperature as a whole.

[0038]

The fuel cell according to the present invention has the following effects and advantages.

A temperature control medium flow channel having the same flow channel structure as the first gas flow channel for flowing the oxidant gas and / or the second gas flow channel for flowing the fuel gas is provided, and the flow direction of the gas is also provided. And the flow direction of the temperature control medium are set to be opposite to each other. Therefore, for example, the oxidant gas flowing through the first gas flow path and the cooling medium flowing through the temperature control medium flow path flow through the same flow path in the front and back in opposite directions. The heat exchange efficiency between the media is improved, and the temperature of the power generation unit can be made uniform. Similarly, for example, the fuel gas flowing through the second gas flow path and the cooling medium flowing through the temperature control medium flow path can make the temperature of the power generation unit uniform.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a fuel cell according to the present invention.

FIG. 2 is a partially exploded perspective view of the fuel cell.

FIG. 3 is a vertical cross-sectional view of the fuel cell.

FIG. 4 is an explanatory diagram of a gas flow path and a cooling medium flow path of a rectifying plate for an oxidant gas that constitutes the fuel cell.

FIG. 5 is an explanatory diagram of a gas flow path and a cooling medium flow path of a fuel gas rectifying plate that constitutes the fuel cell.

FIG. 6 is a vertical cross-sectional explanatory view of a separator that constitutes the fuel cell.

FIG. 7 is a schematic configuration explanatory diagram of a fuel cell according to a conventional technique.

[Explanation of symbols]

10 ... Fuel cell 12 ... Solid polymer electrolyte membrane 14 ... Air electrode 16 ... Hydrogen electrode 18 ... Fuel cell structure 20 ... Separator 40, 42 ... Separator part 44 ... Partition plate 46, 52 ... Manifold plate 50, 56 ... Rectifier plate 50b, 56b ... Gas flow paths 50d, 56d ...
Channel

Claims (4)

[Claims] 1. A fuel cell structure in which a cathode-side electrode and an anode-side electrode are opposed to each other with a solid polymer electrolyte membrane sandwiched therebetween, and a separator sandwiching the fuel cell structure, wherein the separator is the cathode. First and second gas flow paths for flowing an oxidant gas and a fuel gas in parallel to each other in the gravity direction in the side electrode and the anode side electrode, respectively, and partition walls in the first and / or second gas flow paths. And a temperature control medium channel having the same channel structure as that of the first and / or second gas channels, and the gas of the first and / or second gas channels is provided. A fuel cell, wherein a flow direction and a flow direction of the temperature control medium in the temperature control medium flow path are set to be opposite to each other. 2. The fuel cell according to claim 1, wherein the opening cross-sectional area of the first gas passage through which the oxidant gas flows and the temperature control medium provided in the first gas passage through a partition wall. The opening cross-sectional area of the temperature control medium is the opening cross-sectional area of the second gas flow path through which the fuel gas flows, and the opening cut-off of the temperature control medium flow path provided in the second gas flow path through a partition wall. A fuel cell characterized by being set larger than the area. 3. The fuel cell according to claim 1 or 2, wherein the temperature control medium is water, methanol, or a mixed solution of water and methanol. 4. The fuel cell according to claim 1 or 2, wherein the first and second gas flow passages are flow passage structures that allow the oxidizing gas and the fuel gas to flow in a meandering direction parallel to each other and in the direction of gravity. A fuel cell characterized by the following.