JPH01146263A - Current collecting separator - Google Patents

Abstract

PURPOSE:To prevent performance deterioration caused by oxygen shortage by installing a means preventing the blockage of passages in fuel and air supply passages. CONSTITUTION:Horizontal passages 4-5 intersecting to vertical passages 4-2 in air passage in a separator are installed in the air passage, and horizontal passages 4-5 intersecting to vertical passages 4-2 are also installed in the vicinity of the outlet of an air exhaust port. If blockage caused by condensed water arises in some vertical passage 4-2, air flows through horizontal passages 4-5 to bypass the blocked part and returns again to vertical passage 4-2. If all outlets in the lower part of air passage 4-3 are blocked, air is not exhausted, however, at least one exhaust port is opened by the pressure of air to eliminate blockage. If one exhaust port exists, air from each vertical passage flows to this exhaust port. Performance deterioration caused by blockage is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a current collector separator for a fuel cell, and particularly to a current collector separator suitable for a methanol fuel cell.

[Conventional technology]

The configuration of a methanol fuel cell will be explained. Figure 8 (A)
and (B) show an example of a conventional separator.

The current collector separator (10) is made of high-density carbon or the like (specific gravity 1.
8 to 2.0). The figure shows the plane of the separator on the methanol pole side and the AA cross section. The separator has liquid supply hole 1. Two liquid discharge holes 2 are provided in each case. A channel groove 7 is provided to guide the liquid from the supply and discharge holes.

A plate receiver (1) 6 is provided on the channel groove. The central part of the separator is Mizoyama 3-1. A liquid groove 4-1 is provided. Furthermore, floating island-shaped projections 5-1 are provided at the upper and lower portions.

FIGS. 9(A) and 9(B) show a plane of a conventional separator on the air electrode side and a cross section taken along line C-C. A vertical air groove 4-2 is provided in the center of the separator. There is a plate receiver (2) 8 in the air discharge part of the upper part.

FIG. 10 shows a DD cross section in FIG. 9(A).

In the lower section of the air flow groove, the air flow groove 4-3 has a plate (
2) Covered at 9-2. The thickness of the surface receiving the plate is the same as the thickness of the separator.

FIG. 11 shows a BB cross section in FIG. 8(A).

In the cross section of the liquid supply and discharge hole portion, the channel groove 7 is connected to the plate (1
) Covered by 9-1. The thickness of the surface receiving the plate is the same as the thickness of the separator.

FIGS. 12(A) and 12(B) show the shape of a gasket used for sealing when separators are laminated. The gasket 39 is made of soft rubber material or the like. The outer shell and hole have the same dimensions as the separator, and the thickness is thicker than the electrode for the interference, and the part located in the center of the separator is blank.

FIG. 13 shows the structure of the stacked battery. An ion exchange membrane 140 as an electrolyte is connected to an air electrode 41-1 and methanol 42-.
It is sandwiched between two picture electrodes, and gaskets 39 are placed on both sides thereof. Furthermore, current collecting separators (10) are placed on both outer sides, and when these are brought into close contact, a unit battery is constructed. Ion exchange membrane 40. Gasket 39. The space surrounded by the separator (10) constitutes a groove chamber for the air or anolyte flow path. The side where the air electrode is located is the groove chamber of the air flow path, and the side where the methanol electrode is located is the groove chamber of the anolyte flow path.

In reality, unit batteries are stacked in the same number of layers as required.

Next, the anolyte 31 (e.g. 1,5 M Has 0
A mixed solution of 0 M CH2OH + Hz○ is supplied from the liquid supply hole 1 to the channel groove 7, ascends 4-1, and flows out from the upper channel groove 7 to the liquid discharge hole 2.

On the other hand, air 32 is supplied from the top, flows down the air groove 4-2, and is discharged from the bottom.

In this way, electricity is generated by supplying anolite and air to the seven norite groove chambers and the air groove chamber, respectively.

FIG. 14 shows the configuration of a methanol fuel cell and the principle of power generation. An air electrode 41- in which a catalyst is coated on a 9-breathable carbon substrate 41-2 with an ion exchange membrane 40 as an electrolyte in between.
1 and a methanol electrode 42-1, which is also coated with a catalyst on a substrate 42-2, are brought into close contact with the membrane side, and a separator is further placed on the outside to form a pair of unit cells.

Here, when an anolite is supplied to the methanol electrode and air is supplied to the air electrode, CIIaOt(+H2O
-+CC)z+6)(+ +6e-; 6H+ at air electrode
+3/20z+6e--+3HzO (7) An electrochemical reaction occurs. The air electrode is in an electron-deficient state, and the methanol electrode is in an electron-abundant state. When an external circuit is connected, electrons flow from the methanol electrode to the air electrode through that circuit, and power is obtained. This power generation continues as long as air and methanol are supplied to the battery. During power generation, water generated on the air electrode side is discharged to the outside in the form of water vapor by the air. However, since the dew point is about 58° C., when the ambient temperature falls below this, water vapor condenses in the flow path and droplets gradually grow.

FIGS. 15(A) and 15(B) show a partial state of the air flow path of the separator during power generation. In the air flow path, water that permeates through the ion exchange membrane, water in the supplied air, water vapor from generated water, etc. condenses in the atmosphere, adheres, and gradually grows to block the flow path. Air is difficult to flow through the channels to which the condensed water 100 has adhered and in the blocked channels, and since air does not flow, oxygen is insufficient and the channels do not contribute to power generation.

FIG. 16 shows the unit voltage generated by the battery. When the air flow path is not blocked, the generated voltage is 0.4 V/60 mA load, but when the air flow path is blocked, the generated voltage is 0, 1/60
m A load or less, and if left unattended, it will reverse to negative polarity. ``As described above, blockage of air channels by condensed water greatly affects battery performance.However, 1. Until now, no consideration has been given to the shape of air channels that do not become clogged.

[Problem that the invention seeks to solve]

The above-mentioned conventional separator does not take into consideration air flow path clogging due to condensed water, and a stacked battery using this separator has a problem in power generation performance.

An object of the present invention is to prevent air flow paths from being blocked due to changes in the atmosphere in which the battery is placed. In addition, even if a part of the flow path is blocked, the air can flow through the cross flow path provided, reducing the total length of the flow path and
The reason is to prevent the entire system from becoming blocked.

[Means for solving problems]

The above purpose is to have a width of 1 to 5 IIw11 that intersects the conventional vertical flow path.
A horizontal flow path with a depth of 1-2I111 is used as an air flow path for 5-10 meters.
Provided at intervals. This can also be achieved by providing intersecting horizontal flow paths near the outlet of the air discharge section.

Further, a further effect can be obtained by providing a drain curtain made of fiber cloth, net, etc. at the lower end discharge portion of the air flow path so as to be partially in contact with the air flow groove.

[Effect]

If a blockage section due to condensed water is present in the vertical flow path, the horizontal flow path provided to intersect with the vertical air supply flow path will cause the air to bypass the horizontal flow path and return to the vertical flow path again. is formed. In addition, if all the outlets at the lower end of the air flow path are blocked, air cannot be discharged, but at least one outlet is immediately opened by air pressure, so it is not blocked. Furthermore, if there is one outlet, air from each vertical flow path flows to this outlet, thereby preventing performance degradation due to blockage.

Furthermore, the drain curtain provided at the lower end discharge portion of the air flow path weakens the adhesion of condensed water and prevents the discharge port from clogging.

〔Example〕

FIGS. 1A and 1B show an embodiment of the separator of the present invention. FIG. 1(A) shows a plane of the separator on the methanol pole side, and FIG. 1(B) shows a cross section taken along line AA in FIG. 1(A). The separator has liquid supply hole 1. Two liquid discharge holes 2 are provided in each case.

A guide channel groove 7 is provided from the liquid supply and discharge holes.

A plate receiver (1) 6 is provided above the guide channel groove.

The central part of the separator has many groove ridges 3-1, and liquid grooves 4.
-1 is formed. Further, floating island-like projections 5-1 are provided at the upper and lower parts. A notch is provided in the groove ridge 3-1, and this notch becomes a horizontal channel groove 4-5 that intersects the vertical channel groove 4-1.

The depth of the horizontal channel grooves is the same as that of the vertical channel grooves, the width is 1 to 5 m, and the interval is in the range of 5 to 20 mm, and the dimensions and number are appropriately selected based on the size of the separator.

FIG. 2(A) is a plane of the separator on the air electrode side. Figure 2 (B
) shows the C-C cross section. The central part of the separator consists of a groove 4-2 for air flowing from top to bottom and a groove ridge 3-2. Mizoyama 3-2
is provided with a notch, and this notch forms a transverse channel groove 4-5 that intersects with the air groove 4-2.

The depth of the notched horizontal channel groove is the same as that of the vertical channel groove, and the depth is 1~
For the 5m1 interval, select the size and number of separators from a range of 5 to 201m.

At the bottom there is a plate receiver (2) 8.

FIG. 3 is a cross section taken along the line DD in FIG. 2(A), showing a lower cross section of the air flow groove. The lower air flow groove 4-3 is formed by a plate (2
) Covered by 9-2. Groove mount 3-2 that receives the plate
A lateral groove 4-5 is provided in the lateral groove 4-5. The thickness of the surface receiving the plate is the same as the thickness of the separator.

FIG. 4 shows a BB cross section in FIG. 1(A). This is a cross section of the liquid supply and discharge hole portion. The channel groove 7 is a plate (1)
Covered by 9-1. The thickness of the surface receiving the plate is the same as the thickness of the separator.

FIG. 5 is a diagram showing the state of the air flow passage grooves 4-2 of the separator in which a battery is constructed by laminating the separators of the present invention.

In the air flow path groove 4-2, some of the permeate that permeates the ion exchange membrane from the methanol electrode side, moisture contained in the supplied air, and water produced by the electrochemical reaction of the battery pass through the air flow path. This is because it evaporates while flowing and is not discharged, but gradually condenses during operation.

This blocks the channel groove. Moreover, this condensed water 10
0 easily falls through the channel groove and is not discharged, resulting in insufficient oxygen supply to the blocked channel groove, resulting in a decrease in battery performance.

In the separator provided with the horizontal channel grooves of the present invention, the vertical channel grooves 4
If a part of the channel -2 is partially blocked, the air bypasses that area and flows through the horizontal channel groove 4-5 as shown in the figure, so the blockage does not occur.

FIG. 6(A) shows a plane on the air electrode side of Example 2 of the separator of the present invention, and FIG. 6(B) shows its AA cross section. The figure shows the plate holder (2) and plate (2) at the bottom of the air flow groove.
) A drain curtain 101 made of fiber cloth or grid net is inserted between the two. The curtain has a plate holder (2
) and plate (2) to prevent it from falling. Also, a part of the drain curtain is exposed above the groove of the air flow path, but this is provided so that it does not block the air flow path. Further, the thickness of the portion where the curtain is inserted is the same as that of the other portions of the separator.

FIGS. 7(A) and 7(B) are diagrams showing the state of the air flow path side of the separator in which a battery is constituted by the separators shown in FIGS. 6(A) and (B).

Penetrating liquid, generated water, etc. condensate in the air flow path groove 4-2.
During operation, this flows down the air flow groove and reaches the lower end of the separator. However, the droplets 100 of condensed water containing sulfuric acid do not fall from the bottom end, but instead block the exhaust groove where they remain attached6.Therefore, in order to make them easier to fall, a means is needed to weaken the adhesion force. .

In the figure, the adhesion force is weakened by the provided drain curtain, and as shown in Figure 1, the droplets that reach the lower end of the separator tend to fall down through the drain curtain.

Droplets will no longer adhere to the bottom edge.

〔Effect of the invention〕

By using the separator of the present invention, flow path clogging due to condensed water in the air electrode side flow path will not occur.
Oxygen supply to the air electrode is not delayed, eliminating performance deterioration due to lack of oxygen.

Furthermore, by providing a horizontal flow path in the conventional vertical flow path, the area of the catalyst that is in contact with the anolite on the methanol electrode side and actually in contact with oxygen on the air electrode side is increased, which improves battery performance. Further, by providing the lateral flow path, the separator is shaved off by that amount, resulting in a weight reduction of about 5 to 10%.

[Brief explanation of the drawing]

Figure 1 (A) is a plan view of the methanol fuel cell separator of the present invention on the methanol electrode side, and Figure 1 (B) is Figure 1 (A).
2(A) is a plan view of the air electrode side of the methanol fuel cell separator of the present invention, FIG. 2(B) is a sectional view taken along CC of FIG. 2(A), and FIG. The figure is D in Figure 2 (A).
-D sectional view, FIG. 4 is a BB sectional view of FIG. 1(A), FIG. 5 is a model showing the state of the air flow path of the separator of the present invention, and FIG. FIG. 6 (B) is a plan view of the air electrode side of the methanol fuel cell separator of Example (2).
) is an AA sectional view of (A), and FIG. 7(A) is a cross-sectional view of Example (2).
) Diagram showing the state of the air flow path in the separator using a model, Part 7
Figure (B) is a sectional view taken from A to A in (A), Figure 8 (A) is a plan view of a conventional separator on the methanol pole side, and Figure 8 (B) is a sectional view taken from A to A in (A). Figure 9 (A) is a plan view of a conventional separator on the air electrode side, Figure 9 (B) is a sectional view taken from C to C in (A), and Figure 10 is a perspective view of the DD cross section in Figure 9 (A). figure,
FIG. 14 is a diagram showing the principle of power generation. Figure 15 (A) is a diagram showing the state of the air flow path of a methanol fuel cell, Figure 15 (B) is a sectional view from A to A in (A), and Figure 16 is a diagram showing the performance of the unit cell. It is a diagram. DESCRIPTION OF SYMBOLS 1...Liquid supply hole, 2...Liquid discharge hole, 3-1...Mitch crest, 4-1...Liquid groove, 4-2...Air groove, 4-3...
...Air flow path, 4-5...Horizontal flow path groove, 5-1...Protrusion, 6...Plate receiver (1), 7...Flow path groove, 8
...Plate holder (2). 9-1...Plate (1), 9-2...Plate (
2) 10... Separator, 31... Anolite, 3
2... Air, 39... Gasket, 40... Ion exchange membrane, 41-1... Air electrode, 42-1... Methanol electrode, 100... Condensed water (droplets), 101 ...
drain curtain. Figure 1 (A) '' Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 (A CB) Figure 8 (A) A-, -A Figure 9 (A) (B) 1O Figure 1I Figure 1Z (A) CB) Figure 14Z Figure 15 (A) <B)

Claims (1)

[Scope of Claims] 1. An electrolyte ion exchange membrane is sandwiched between a fuel electrode that electrochemically oxidizes a fuel substance and an oxidizer electrode that electrochemically cyclizes an oxidizing agent, and the outside thereof is made of a conductor and In a battery separator having a flow path for supplying fuel and an oxidizer and in which separators for collecting electricity generated by both electrodes are densely laminated, a means for preventing blockage of the flow path is provided in the fuel and air supply flow path. A current collecting separator characterized by: 2. A current collector separator according to claim 1, characterized in that a flow path is provided that intersects with the existing flow path. 3. A current collecting separator according to claim 2, characterized in that the existing vertical channels are provided with horizontal channels that intersect with each other, and the existing horizontal channels are provided with vertical channels that intersect with each other. 4. A current collecting separator according to claim 3, characterized in that the dimensions and intervals of the intersecting channels are provided at the same or different positions on the front and back sides of the separator. 5. A current collector separator according to claim 2, characterized in that a flow path intersecting the air flow path is also provided at a position near the discharge portion of the air flow path. 6. A current collector separator according to claim 1, characterized in that a pseudo condensation water discharge means such as a fiber cloth or a lattice network is attached to the flow path in the vicinity of the discharge portion of the air flow path.