JP4969864B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell provided with a manifold for allowing a reaction gas to flow through a flow path of a battery body, and more particularly to a fuel cell in which processing of condensed water inside is improved.

  A fuel cell is a power generator that supplies a fuel gas, such as hydrogen, and an oxidant gas, such as air, to the cell body to cause an electrochemical reaction, converting the chemical energy of the fuel directly into electrical energy and taking it out. Device. This fuel cell has been evaluated as a power generation device that has high power generation efficiency and is excellent in environmental performance with less pollutant emission and noise.

  The structure of such a fuel cell using a solid polymer membrane will be described with reference to FIGS. That is, as shown in FIG. 12, the fuel cell main body has a laminated body 11 in which a plurality of unit cells 1 are laminated, and a current collector plate 2 and a fastening plate 3 are disposed at both ends of the laminated body 11, It is configured by tightening with a stud 4 and a nut and a disc spring. Each cell 1 has a fuel electrode and an oxidant electrode coated with a catalyst at both ends of a solid polymer membrane, and a fuel electrode channel plate having a fuel electrode channel and an oxidant electrode channel at both ends thereof and an oxidation electrode. It is comprised by the agent electrode flow-path board.

  A fuel electrode inlet manifold 6, a fuel electrode outlet manifold 7, an oxidant electrode inlet manifold 8, and an oxidant electrode outlet manifold 9 are disposed around the fuel cell body as shown in the cross-sectional view of FIG. The fuel gas enters the fuel electrode inlet manifold 6, passes through the fuel electrode channel 10 of the fuel electrode channel plate 5, and is discharged from the fuel electrode outlet manifold 7 to the outside. Similarly, the oxidant gas enters the oxidant electrode inlet manifold 8, passes through the oxidant electrode channel of the oxidant electrode channel plate (not shown), and is discharged to the outside from the oxidant electrode outlet manifold 9.

  As a fuel gas used in such a fuel cell, city gas or the like is reformed into hydrogen by a reformer and supplied to the fuel cell. Normally, the reformed fuel gas contains steam. Yes. For this reason, when the fuel gas dew point is higher than the temperature in the fuel electrode inlet manifold when it is supplied to the fuel cell, water in the fuel gas condenses in the fuel electrode inlet manifold, and water droplets adhere to the inner wall of the manifold. To do. There is a problem that the flow rate of gas supplied to a specific cell is reduced because the water droplets block the gas flow path. Further, the gas discharged from the fuel cell main body similarly contains steam, and there is a problem that the drain accumulated in the outlet manifold interferes with the gas flow and affects the cell performance.

  In order to cope with this, for example, conventional techniques as shown in Patent Documents 1 to 3 have been proposed. First, in Patent Document 1, the gas inlet manifold is positioned above the lamination surface, and the manifold is inclined to prevent water droplets adhering to the top plate from dropping on the lamination surface and blocking the gas flow path. A technique for providing a drain discharge port is disclosed.

  Patent Document 2 discloses a technique in which a partition plate and a drain receiver that cover the entire gas flow path are provided, and water drops are prevented from dripping directly on the laminated surface. Patent Document 3 discloses a technique in which the fuel cell main body is inclined so that the drain accumulated in the manifold is easily discharged using gravity, so that the drain becomes lower in the gas traveling direction of the manifold. Yes.

JP 2004-207106 A JP 2004-185935 A JP 2004-146303 A

   By the way, in the conventional fuel cell, as pointed out in Patent Document 1 and Patent Document 2, there is a problem that the gas flow path is blocked by water droplets dripping from the top plate located above the laminated surface. . In order to avoid this, for example, in the example shown in FIG. 13, the ceiling surfaces of the fuel electrode inlet manifold 6 and the fuel electrode outlet manifold 7 are in a positional relationship perpendicular to the stacked surface.

  However, in such a case, a problem has been discovered in which water droplets adhering to the top plate travel along the laminated surface, block the gas flow path, and affect the cell performance. In particular, when the fuel gas flow path is blocked, the electrodes may corrode. And it was found that such a problem cannot be solved even if the fuel cell body is tilted so that the gas in the manifold becomes lower in the gas traveling direction, as shown in Patent Document 3.

  The present invention has been proposed in order to solve the above-described problems of the prior art, and its purpose is to prevent the gas flow path from being blocked by water droplets adhering to the manifold, and to react gas to each cell. It is an object of the present invention to provide a high-performance and durable fuel cell in which the flow and the electromotive force of each cell are uniform and a specific cell is not damaged.

In order to achieve the above object, the present invention provides an electrolyte membrane, a fuel electrode and an oxidant electrode respectively disposed on both surfaces of the electrolyte membrane, and a flow path for supplying a reaction gas to the fuel electrode and the oxidant electrode. In a fuel cell in which at least one cell including a flow path plate is stacked , a plurality of manifolds that circulate reaction gas through the flow path of the cell are provided on the side of the fuel cell, At least one of the manifolds is disposed on the side of the fuel cell so that the reaction gas flows in a horizontal direction from the flow path of the flow path plate. It is characterized by being inclined downward as it goes away from the outlet of the channel .

  In the present invention as described above, by continuing the operation, water droplets condensing on the ceiling inside the manifold flow to the inner wall of the manifold without flowing toward the cell stacking surface due to the inclination provided on the ceiling. As a result, it is possible to prevent the reaction gas flow path in the cell from being blocked.

  According to the present invention as described above, it is possible to prevent clogging of the gas flow path due to water droplets adhering to the manifold, and the flow of the reaction gas to each cell and the electromotive force of each cell can be uniform and a specific cell can be damaged. A high-performance and durable fuel cell can be provided.

  The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be specifically described with reference to the drawings. Note that a part of the description of the same configuration and operation as those of the prior art shown in FIGS.

[First embodiment: FIGS. 1 to 3]
[Constitution]
First, a first embodiment will be described with reference to FIGS. As shown in FIG. 1, this embodiment has the same basic configuration as the prior art shown in FIG. 13, and a plurality of manifolds are arranged around the stacked body 11 of the cell 1 (see FIG. 12). Has been. Each manifold is oxidized to a fuel electrode inlet manifold 6 and a fuel electrode outlet manifold 7 for allowing fuel gas to flow to the fuel electrode flow channel 10 of the fuel electrode flow channel plate 5 and an oxidant electrode flow channel of an oxidant electrode flow channel plate (not shown). An oxidant electrode inlet manifold 8 and an oxidant electrode outlet manifold 9 through which the agent gas flows are configured.

  Here, the oxidant electrode inlet manifold 8 is located in the upper part of the laminated body 11, and the oxidant electrode outlet manifold 9 is located in the lower part of the laminated body 11. On the other hand, the fuel electrode inlet manifold 6 and the fuel electrode outlet manifold 7 are provided at positions that are in contact with the flow path plates on both sides of the stacked body 11, and are disposed at positions that are perpendicular to the stacking direction of the cells 1. ing.

  In the present embodiment, the fuel electrode outlet manifold 7 has the following structural features. That is, as shown in FIG. 2, the inner side surface 70 of the fuel electrode outlet manifold 7 is opposed to the side surface of the stacked body 11 of the cell 1. The top plate inside the fuel electrode outlet manifold 7 is provided with an inclined portion 71 that is inclined downward from the laminated body 11 toward the inner surface 70.

[Action]
The operation of the present embodiment having the above-described configuration is as follows. First, a general mechanism when condensed water is generated inside the fuel cell as in this embodiment will be described. That is, the unit cell generates heat with the electrochemical reaction. For example, in a polymer electrolyte fuel cell, in consideration of the heat resistance of the polymer electrolyte membrane, the unit cell temperature is usually maintained at about 70 ° C. to 80 ° C. with cooling water or the like.

  On the other hand, the outer wall of the manifold is at the same temperature as the outside air or inside the package in which the fuel cell is incorporated. For this reason, there is a temperature difference between the inner wall and the outer wall of the manifold where the temperature of the inner wall is high and the temperature of the outer wall is low.

  Here, the fuel gas or the oxidant gas that has passed through the fuel electrode channel and the oxidant electrode channel in the cell is discharged to the fuel electrode outlet manifold or the oxidant electrode outlet manifold (hereinafter referred to as the outlet manifold). . In the cell, water is generated by humidifying the electrolyte membrane sandwiched inside the cell or by an electrochemical reaction, so that the fuel gas or oxidant gas flows from the fuel electrode channel or oxidant electrode channel. When discharged to the outlet manifold, the relative humidity is almost 100%.

  As a result, moisture contained in the fuel gas or the oxidant gas is condensed on the inner wall of the outlet manifold. The water droplets thus generated by condensation gradually grow as the operation continues. The water droplets formed on the top plate of the outlet manifold eventually move to the ground plate due to the influence of gravity, but the water droplets cause the following problems.

  For example, as shown in the prior art in FIG. 3 (the white arrow indicates the fuel gas flow direction), the water droplets W are dropped directly, or the laminated surface of the cells 1 and the inner surface of the fuel electrode outlet manifold 7 that is in contact with the cell 1 It reaches and reaches the main plate. In particular, when traveling through the laminated surface of the cell 1, the fuel electrode channel 10 or the oxidant gas channel is blocked by the water droplets W, and the flow of the fuel gas or oxidant gas may be temporarily interrupted. Arise.

  However, in the present embodiment, as shown in FIG. 2, the top plate of the fuel electrode outlet manifold 7 is provided with an inclined portion 71 that descends toward the inner surface 70. For this reason, the water droplets W formed on the top plate pass through the inner wall of the fuel electrode outlet manifold 7 facing the stacked surface without flowing to the stacked surface side of the cell 1. Further, since the fuel electrode outlet manifold 7 is in contact with the flow path plate of the cell 1, the water droplet W on the cell 1 side also moves down the inner surface 70 along the inclined portion 71. As a result, the fuel electrode channel 10 or the oxidant electrode channel in the cell 1 can be prevented from being blocked.

[effect]
According to the present embodiment as described above, by providing the inclined portion 71 on the top plate of the fuel electrode outlet manifold 7, it is possible to prevent the flow of water droplets on the stacked surface of the cells 1 and the hindrance to the gas flow. As a result, the flow rate of the reaction gas flows almost uniformly in each cell 1, so that the specific cell 1 is prevented from being damaged by the lack of the reaction gas, and a high-performance and durable fuel cell can be configured.

[Second Embodiment: FIGS. 4 and 5]
[Constitution]
A second embodiment of the present invention will be described with reference to FIGS. The present embodiment is basically the same configuration as that of the first embodiment, but is an aspect in the case where the fuel electrode outlet manifold 7 is configured as a return manifold. That is, for example, the fuel gas, together with the electrochemical reaction in the cell 1, consumes only hydrogen and does not consume other components. Therefore, the hydrogen concentration decreases as the fuel electrode flow path 10 becomes the wake.

  Therefore, in the present embodiment, as shown in FIGS. 4 and 5, by providing a partition 61 inside the fuel electrode inlet manifold 6, a single manifold can have both functions of an inlet manifold and an outlet manifold. Yes. The other fuel electrode outlet manifold 7 is a fuel electrode flow path different from the fuel electrode flow path 10 from which the fuel gas discharged from the fuel electrode flow path 10 of the cell 1 is once joined and then discharged. 10 is a return manifold for returning the fuel gas so as to supply the fuel gas.

  In this way, the top plate of the fuel electrode outlet manifold 7 configured as a return manifold is inclined downward from the stacked body 11 toward the inner surface 70 as in the first embodiment. An inclined portion 71 is provided.

[Action]
The operation of the present embodiment as described above is as follows. That is, since the inclined portion 71 is provided on the top plate of the fuel electrode outlet manifold 7 configured as a return manifold, the water droplets formed on the top plate are transferred to the cell 1 as in the first embodiment. Without passing through the laminated surface of the cell 1, it reaches the ground plane through the inner surface of the fuel electrode outlet manifold 7 facing the laminated surface of the cells 1.

[effect]
According to the present embodiment as described above, similarly to the first embodiment, the cell 1 can be prevented from being damaged, and a high-performance and durable fuel cell can be configured. Can be distributed efficiently.

[Third Embodiment ... FIG. 6]
[Constitution]
A third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 6, the present embodiment has a so-called internal manifold structure in which a flow path plate 80 (fuel electrode flow path plate or oxidant electrode flow path plate) and a manifold 81 in the cell 1 are integrally formed. Is. That is, a meandering flow path 82 is formed in the flow path plate 80, and manifolds 81 each having a semi-elliptical cross section with respect to the stacking direction of the cells 1 are provided at both ends of the flow path 82. . Thus, since the cross section of the manifold 81 is semi-elliptical, the ceiling inside the manifold 81 is an inclined portion that faces downward from the flow path 82 side to the outside.

[Action]
The operation of the present embodiment having the above-described configuration is as follows. That is, a continuous manifold 81 space is formed by connecting the flow path plates 80 in each of the stacked cells 1, but the cross section is semi-elliptical and the ceiling is an inclined portion. When a water droplet drops from the upper part to the lower part, it does not flow to the flow channel 82 side and obstruct gas flow.

[effect]
According to the present embodiment as described above, in the laminated body using the flow path plate 80 in which the flow path 82 and the manifold 81 are integrated, it is possible to prevent the inflow of water droplets that hinder gas flow. As in the first embodiment, the high-performance and durable fuel cell can be configured by preventing the cell 1 from being damaged, and a small size and space saving can be realized.

[Fourth Embodiment ... FIG. 7]
[Constitution]
A fourth embodiment of the present invention will be described with reference to FIG. As shown in FIG. 7A, this embodiment basically has the same configuration as that of the second embodiment described above, and the fuel electrode outlet manifold 7 is configured as a return manifold. A partition 61 is provided inside 6.

  However, in the present embodiment, as shown in FIGS. 7A to 7C, a plurality of grooves 72 are formed in the vertical direction from the inclined portion 71 to the inner side surface 70 of the fuel electrode outlet manifold 7. Yes.

[Action]
The operation of the present embodiment as described above is as follows. That is, as the operation is continued, water droplets are condensed on the inclined portion 71 and the inner side surface 70 of the fuel electrode outlet manifold 7 facing the side surface of the cell 1. Since the water droplets are promoted to flow downward by entering the vertical grooves 72, they do not grow greatly while attached to the inner wall, and reach the bottom surface early.

[effect]
According to the present embodiment as described above, the same effect as that of the second embodiment is obtained, and the flow of condensed water droplets is promoted by the groove 72. Is more reliably prevented.

[Fifth Embodiment: FIGS. 8 and 9]
[Constitution]
A fifth embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 8 and 9, the present embodiment basically has the same configuration as that of the second embodiment described above, and the fuel electrode outlet manifold 7 is configured as a return manifold. A partition 61 is provided inside 6.

  However, in the present embodiment, a means for keeping warm or heating is provided on the outer wall of the fuel electrode outlet manifold 7. For example, FIG. 8 shows a case where a heat insulating material 73 is provided, and FIG. 9 shows a case where a heater 74 is installed.

[Action]
The operation of the present embodiment as described above is as follows. That is, by installing the heat insulating material 73 or the heater 74 on the outer wall of the fuel electrode outlet manifold 7, the temperature of the outer wall of the fuel electrode outlet manifold 7 can be increased. Therefore, since the temperature of the outer wall can be made closer to the temperature of the inner wall of the fuel electrode outlet manifold 7 that is heated by the cell 1 and the temperature difference between the two can be reduced, an effect of suppressing moisture growth inside can be obtained. .

[effect]
According to the present embodiment as described above, the same effects as those of the second embodiment can be obtained and the condensation of moisture inside the fuel electrode outlet manifold 7 can be suppressed. Inflow to the water is more reliably prevented.

[Sixth Embodiment ... FIG. 10]
[Constitution]
A sixth embodiment of the present invention will be described with reference to FIG. As shown in FIG. 10, this embodiment is basically the same configuration as that of the second embodiment described above, and the fuel electrode outlet manifold 7 is configured as a return manifold. A partition 61 is provided.

  However, in this embodiment, a hole is formed in the bottom plate of the fuel electrode outlet manifold 7, and a drain port 75 is provided in the hole. The drain port 75 is a discharge port that discharges moisture that has been condensed and lowered inside the fuel electrode outlet manifold 7 to the outside.

[Action]
The operation of the present embodiment as described above is as follows. That is, as the operation is continued, water droplets are condensed on the inclined portion 71 and the inner side surface 70 of the fuel electrode outlet manifold 7. The water droplets reach the bottom plate along the inclined portion 71 and the inner side surface 70, but are smoothly discharged to the outside of the stacked body 11 through the drain port 75 provided on the bottom plate.

[effect]
According to the present embodiment as described above, the same effect as that of the second embodiment can be obtained, and the drainage of the condensed water droplets is promoted by the drain port 75. Inflow is more reliably prevented.

[Seventh Embodiment ... FIG. 11]
[Constitution]
A seventh embodiment of the present invention will be described with reference to FIG. As shown in FIG. 11, this embodiment basically has the same configuration as that of the second embodiment described above, and the fuel electrode outlet manifold 7 is configured as a return manifold. A partition 61 is provided.

  However, in this embodiment, the inclined portion is not provided inside the fuel electrode outlet manifold 7, but the flow path plate 90 constituting the cell 1 has a side surface facing the fuel electrode outlet manifold 7 in the stacked body 11 facing downward. It has a trapezoidal shape so as to be inclined. That is, the horizontal direction cross-sectional area of the flow path plate 90 and the laminated body 11 on which the flow path plate 90 is laminated is larger as it goes upward and becomes smaller as it goes downward. Further, the fuel electrode outlet manifold 7 is disposed in an inclined manner in accordance with the side surface of the stacked body 11.

[Action]
The operation of the present embodiment as described above is as follows. That is, since the fuel electrode outlet manifold 7 configured as a return manifold is inclined and arranged in accordance with the inclined surface of the stacked body 11, the ceiling is an inclined portion. For this reason, water droplets formed on the top plate do not pass through the stacked surface of the cells 1, but reach the ground plane through the inner surface of the fuel electrode outlet manifold 7 facing the stacked surface of the cells 1.

[effect]
According to the present embodiment as described above, the same effect as that of the second embodiment can be obtained by the inclined portion of the ceiling of the fuel electrode outlet manifold 7, and water drops can flow into the gas flow path. Can be separated from the battery body, so that it is possible to more reliably prevent the adverse effects caused by the inflow of water droplets.

[Other Embodiments]
The present invention is not limited to the embodiment as described above. For example, in the first embodiment, an example in which the inclined portion is provided on the top plate of the fuel electrode outlet manifold has been shown. However, also in the fuel electrode inlet manifold, the fuel gas supplied to the fuel electrode inlet manifold is the cell temperature. If the dew point is higher than the fuel inlet gas manifold temperature, water droplets are formed on the top plate, and the flow of gas to the cells is blocked when dropping on the ground plate through the cell stacking surface.

  Therefore, the inflow of water droplets to the cells may be prevented by providing an inclined portion on the top plate for the fuel electrode inlet manifold. Furthermore, you may provide an inclination part in the partition in the fuel electrode inlet manifold of 2nd, 4th, 5th, 6th, and 7th embodiment.

  Further, when the oxidant electrode inlet manifold and the oxidant electrode outlet manifold are arranged on both sides of the laminated body, the flow of the oxidant is similarly blocked by water droplets formed on the top plate. By providing the inclined portion in the fuel electrode inlet manifold or the oxidant manifold, the same effect as described above can be obtained. Even when the partition portion is provided in the fuel electrode inlet manifold or the oxidant manifold, the inclined portion can be provided in the partition portion.

  In the third embodiment, the manifold cross section in the stacking direction is a semi-elliptical shape, but the shape is not limited to this. That is, the same effect can be obtained by providing an inclination that reduces the cross-sectional area of the flow path plate from the cell stacking surface side toward the opposing manifold inner surface. In each of the above embodiments, the flow and discharge of water droplets can be further promoted by applying a coating (for example, fluororesin processing) that imparts water repellency to the inner wall of the manifold.

  In the fifth embodiment, the heat insulating material or the heater is attached only to the return manifold, but the same effect can be obtained by attaching the heat insulating material or the heater to the inlet manifold or the outlet manifold of the fuel electrode or the oxidizer electrode. It is done. Furthermore, in the seventh embodiment, the drain port is installed only in the return manifold, but the same effect can be obtained by installing the drain port in the inlet manifold or outlet manifold of the fuel electrode or oxidant electrode.

1 is a vertical sectional view of a fuel cell according to a first embodiment of the present invention. FIG. 2 is a perspective view showing the inside of a fuel electrode outlet manifold in the embodiment of FIG. 1. The perspective view which shows the inside of the fuel electrode exit manifold of the conventional fuel cell. The vertical sectional view in the 2nd embodiment of the fuel cell of the present invention. FIG. 5 is a perspective view of the embodiment of FIG. 4. The top view which shows the flow-path board in 3rd Embodiment of the fuel cell of this invention. The perspective view (A) which shows 4th Embodiment of the fuel cell of this invention, the vertical sectional view (B) of a fuel electrode outlet manifold, and the perspective view (C) of a fuel electrode outlet manifold. The vertical sectional view which shows the example using the heat insulating material in 5th Embodiment of the fuel cell of this invention. The vertical sectional view showing the example using the heater in a 5th embodiment of the fuel cell of the present invention. The vertical sectional view showing the 6th embodiment of the fuel cell of the present invention. The perspective view which shows 7th Embodiment of the fuel cell of this invention. The vertical sectional view showing an example of the conventional fuel cell. FIG. 13 is a vertical sectional view showing a manifold constituting the fuel cell of FIG. 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cell 2 ... Current collecting plate 3 ... Fastening plate 4 ... Stud 5 ... Fuel electrode flow path plate 6 ... Fuel electrode inlet manifold 7 ... Fuel electrode outlet manifold 8 ... Oxidant electrode inlet manifold 9 ... Oxidant electrode outlet manifold 10 ... Fuel electrode flow path 11 ... Laminate body 61 ... Partition 70 ... Inner surface 71 ... Inclined portion 72 ... Groove 73 ... Insulating material 74 ... Heater 75 ... Drain port 80 ... Channel plate 81 ... Manifold 82 ... Channel 90 ... Flow path Board

Claims (10)

A cell comprising an electrolyte membrane, a fuel electrode and an oxidant electrode respectively disposed on both surfaces of the electrolyte membrane, and a flow path plate constituting a flow path for supplying a reaction gas to the fuel electrode and the oxidant electrode, In a fuel cell in which at least one sheet is laminated,
On the side of the fuel cell, there are provided a plurality of manifolds for circulating a reaction gas through the flow path of the cell,
At least one of the manifolds is disposed on the side of the fuel cell so that the reaction gas flows in a horizontal direction from the flow path of the flow path plate,
The fuel cell according to claim 1, wherein an inclination toward the lower side is attached to a ceiling portion inside the manifold as the distance from the outlet of the cell flow path is increased. The flow path plate has a fuel electrode flow path plate having a fuel electrode flow path for supplying fuel gas to the fuel electrode, and an oxidant electrode flow path for supplying oxidant gas to the oxidant electrode. An oxidant electrode flow path plate,
The manifold includes a fuel electrode inlet manifold for supplying fuel gas to the fuel electrode channel, an oxidant electrode inlet manifold for supplying oxidant gas to the oxidant electrode channel, and the fuel electrode channel. 2. The fuel cell according to claim 1, further comprising: a fuel electrode outlet manifold that discharges fuel gas from the oxidant electrode; and an oxidant electrode outlet manifold that discharges oxidant gas from the oxidant electrode flow path. The manifold has a return manifold for supplying the reaction gas to a flow path different from the flow path after the reaction gas discharged from the flow path is merged,
3. The fuel cell according to claim 1, wherein the slope is attached to a ceiling portion inside the return manifold.   The fuel cell according to any one of claims 1 to 3, wherein the manifold is integrated with the flow path plate.   The fuel cell according to any one of claims 1 to 4, wherein the manifold is attached so as to be in contact with the flow path plate. The manifold, the fuel cell according to any one of claims 1 to 3 and 5, characterized in that a groove is attached to an inner surface thereof. The manifold, fuel cell according to any one of claims 1～3,5,6, characterized in that it is constructed using high insulation material. The manifold, the fuel cell according to any one of claims 1～3,5～7, characterized in that the heating means. The manifold, the fuel cell according to any one of claims 1-8, characterized in that the outlet of the liquid are mounted. The fuel cell according to any one of claims 1 to 9 , wherein a horizontal cross-sectional area of the flow path plate increases toward an upper portion.

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