JP5395521B2 - Fuel cell stack - Google Patents

Description

  The present invention provides a reaction gas in which a plurality of power generation cells are stacked in a horizontal direction, end plates are disposed at both ends in the stacking direction, and at least a reaction gas that is a fuel gas or an oxidant gas is supplied along the stacking direction. The present invention relates to a fuel cell stack in which a supply communication hole and a reaction gas discharge communication hole for discharging the reaction gas are provided to be positioned vertically.

  A fuel cell supplies a fuel gas (mainly hydrogen-containing gas) and an oxidant gas (mainly oxygen-containing gas) to the anode-side electrode and the cathode-side electrode and causes them to react electrochemically. It is a system that obtains electrical energy.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) provided with an anode electrode and a cathode electrode on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. Has a cell. This power generation cell is normally used as a fuel cell stack by alternately laminating a predetermined number of electrolyte membrane / electrode structures and separators.

  In this type of fuel cell, in order to effectively use fuel gas such as hydrogen gas, the fuel off-gas that is partially used and discharged from the fuel cell is supplied again to the anode electrode as fuel gas. Has been done. However, the fuel off-gas contains water generated by the power generation reaction of the fuel cell, and water vapor is easily condensed due to a decrease in temperature, and water droplets are easily generated. When the water droplets are introduced into the fuel cell, there is a problem that it is difficult to stably maintain the power generation performance of the fuel cell.

  On the other hand, the electrolyte membrane needs to be humidified in order to exhibit desired proton conductivity. Accordingly, the reaction gas (oxidant gas and fuel gas) supplied to the fuel cell is pre-humidified, and condensation occurs in the reaction gas path before the humidified reaction gas is introduced into the fuel cell. There is a fear. For this reason, the produced | generated condensed water may be introduce | transduced in a fuel cell.

  Therefore, for example, a fuel cell stack disclosed in Patent Document 1 is known. In the fuel cell stack, as shown in FIG. 9, a plurality of cells 1 are stacked, and insulators 2a and 2b and end plates 3a and 3b are disposed at both ends of the stacked body of cells 1.

  In the fuel cell stack, an oxidant gas supply manifold 4 and an oxidant gas discharge manifold 5 are formed penetrating in the stacking direction. An oxidant drain discharge pipe 6 is connected to the outlet of the oxidant gas supply manifold 4.

  The oxidant drain discharge pipe 6 is introduced with oxidant gas and stagnant water flowing through the oxidant gas supply manifold 4 and is disposed in a water recovery tank (not shown). For this reason, the amount of condensed water in the oxidant gas supply manifold 4 is reduced, and mixing of condensed water into the cell 1 is suppressed.

JP 2008-270159 A

  In the above-mentioned Patent Document 1, a tightening load is applied between the end plates 3a and 3b in a state where a plurality of cells 1 are stacked in the horizontal direction, thereby forming a fuel cell stack. For this reason, in the fuel cell stack, in particular, the cell 1 on the intermediate side in the stacking direction is easily bent so as to move to the lowest position (see a two-dot chain line in FIG. 9). Accordingly, in the oxidant gas supply manifold 4, the height of the intermediate portion in the stacking direction is the lowest with respect to the direction of gravity, while the height position on the end plates 3a and 3b side is the highest, resulting in a curved shape as a whole. easy.

  Thereby, in the cell 1 arranged at the intermediate portion in the stacking direction, the condensed water tends to stay in the oxidant gas supply manifold 4, and the condensed water is not pushed out to the oxidant drain discharge pipe 6. There is a problem of being introduced in.

  The present invention solves this type of problem, and provides a fuel cell stack capable of reliably performing good wastewater treatment with a simple configuration and utilizing the deflection of the entire fuel cell stack. Objective.

  The present invention provides a reaction gas in which a plurality of power generation cells are stacked in a horizontal direction, end plates are disposed at both ends in the stacking direction, and at least a reaction gas that is a fuel gas or an oxidant gas is supplied along the stacking direction. The present invention relates to a fuel cell stack in which a supply communication hole and a reaction gas discharge communication hole for discharging the reaction gas are provided in a vertical position.

The fuel cell stack includes a drainage member disposed only at an intermediate portion in the stacking direction of the power generation cells, and the drainage member allows moisture contained in the reaction gas supplied to the reaction gas supply communication hole to flow along the gravity direction. A drain channel for discharging is provided.

  The drainage member is provided with an upper opening that communicates with the reaction gas supply communication hole on the upper side, a lower opening that communicates with the reaction gas discharge communication hole on the lower side, and at least one surface includes the upper portion It is preferable that the drain channel that communicates the opening and the lower opening is provided.

  Furthermore, the drainage member has a cathode side upper opening which is an upper opening communicating with an oxidant gas inlet communication hole which is a reaction gas supply communication hole on the upper side, and a fuel gas inlet communication hole which is the reaction gas supply communication hole. A cathode-side lower opening that is a lower opening that communicates with an oxidant gas outlet communication hole that is a reaction gas discharge communication hole on the lower side, and the reaction An anode-side lower opening that is the lower opening communicating with the fuel gas outlet communication hole that is a gas discharge communication hole is provided, and the cathode-side upper opening and the cathode-side lower opening are provided on one surface of the drainage member. A cathode-side drain channel, which is the drain channel communicating with a portion, is formed, and the other surface of the drainage member communicates with the anode-side upper opening and the anode-side lower opening. The anode drain passage said a drain flow path is formed preferably.

  Furthermore, in this fuel cell stack, it is preferable that a drain opening is provided in the lower opening portion below the reaction gas discharge communication hole.

  In the fuel cell stack, a first power generation cell group in which a plurality of power generation cells are stacked is provided between the drainage member and the one end plate, while the drainage member and the other end plate are disposed between the drainage member and the other end plate. Includes a second power generation cell group in which a plurality of the power generation cells are stacked, and the drainage member includes a reaction gas supply communication hole of the first power generation cell group and a reaction gas supply of the second power generation cell group. It is preferable that moisture is supplied from the communication hole.

  In the present invention, the drainage member is disposed at an intermediate portion in the stacking direction of the power generation cells, that is, at a portion that is easily bent downward of the fuel cell stack. Therefore, moisture in the reaction gas supplied to the reaction gas supply communication hole smoothly moves to the drainage member side along the inclination of the reaction gas supply communication hole, and the drain flow path provided in the drainage member Along the direction of gravity.

  As a result, it is possible to reliably perform good wastewater treatment with a simple configuration, utilizing the deflection of the entire fuel cell stack.

1 is a schematic perspective view of a fuel cell stack according to a first embodiment of the present invention. It is the II-II sectional view taken on the line of FIG. 1 of the said fuel cell stack. 2 is an exploded perspective view of a fuel cell constituting the fuel cell stack. FIG. FIG. 3 is an exploded perspective view of a main part of the fuel cell stack. It is front explanatory drawing of the drainage member which comprises the said fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. FIG. 7 is a cross-sectional view of the fuel cell stack taken along line VII-VII in FIG. 6. It is front explanatory drawing of the drainage member which comprises the said fuel cell stack. 2 is an explanatory diagram of a fuel cell stack of Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, in the fuel cell stack 10 according to the first embodiment of the present invention, a plurality of fuel cells (power generation cells) 12 are stacked in the arrow A direction (horizontal direction). The first terminal plate 14a, the first insulating plate 16a and the first end plate 18a are stacked at one end in the stacking direction of the fuel cell 12, while the second terminal plate 14b and the second insulating plate are stacked at the other end in the stacking direction. 16b and the second end plate 18b are stacked.

  As shown in FIG. 3, in the fuel cell 12, the electrolyte membrane / electrode structure 20 is sandwiched between the first and second separators 22 and 24. Although the 1st and 2nd separators 22 and 24 are comprised by the carbon separator, you may comprise by metal separators, such as a steel plate, a stainless steel plate, an aluminum plate, or a plating treatment steel plate, for example. The first separator 22, the electrolyte membrane / electrode structure 20, and the second separator 24 are stacked with a seal member (not shown) interposed therebetween.

  One end edge (upper edge) of the fuel cell 12 in the direction of arrow C (vertical direction in FIG. 3) communicates with each other in the direction of arrow A, which is the stacking direction, and an oxidant gas such as an oxygen-containing gas An oxidant gas inlet communication hole 26a for supplying and a fuel gas inlet communication hole 28a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow B direction (horizontal direction).

  A bottom surface 27 constituting the oxidant gas inlet communication hole 26a is inclined downward and outward, and a concave portion 27a is provided at the bottom of the bottom surface 27. A bottom surface 29 constituting the fuel gas inlet communication hole 28 a is inclined downward and outward, and a recess 29 a is provided at the bottom of the bottom surface 29.

  The other end edge (lower end edge) of the fuel cell 12 in the direction of arrow C communicates with each other in the direction of arrow A to discharge the fuel gas outlet communication hole 28b for discharging the fuel gas and the oxidant gas. For this purpose, the oxidant gas outlet communication holes 26b are arranged in the arrow B direction.

  A plurality of, for example, two cooling medium inlet communication holes 30a for supplying a cooling medium and two cooling medium outlet communication holes for discharging the cooling medium are provided at both ends of the fuel cell 12 in the arrow B direction. 30b is provided.

  An oxidant gas flow path 32 communicating with the oxidant gas inlet communication hole 26a and the oxidant gas outlet communication hole 26b is provided on the surface 22a of the first separator 22 facing the electrolyte membrane / electrode structure 20.

  A fuel gas passage 34 communicating with the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b is provided on the surface 24a of the second separator 24 facing the electrolyte membrane / electrode structure 20.

  A cooling medium that connects the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 that constitute the fuel cells 12 adjacent to each other. A flow path 36 is provided.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 38 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 40 and an anode side electrode 42 that sandwich the solid polymer electrolyte membrane 38. With.

  The cathode side electrode 40 and the anode side electrode 42 are formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. An electrode catalyst layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 38.

  As shown in FIGS. 1, 2, and 4, the fuel cell stack 10 includes a drainage member 44 disposed at an intermediate portion in the stacking direction of the fuel cell 12.

  The fuel cell stack 10 includes a first power generation cell group 12a in which a plurality of fuel cells 12 are stacked between a drainage member 44 and a first end plate 18a, while the drainage member 44 and the second end plate 18b. Between the two, a second power generation cell group 12b in which a plurality of fuel cells 12 are stacked is provided.

  The drainage member 44 is made of, for example, a carbon plate. As shown in FIGS. 4 and 5, the drainage member 44 communicates with the cathode side upper opening (upper opening) 46a communicating with the oxidant gas inlet communication hole 26a on the upper side and the fuel gas inlet communication hole 28a. An anode side upper opening (upper opening) 48a is provided.

  The cathode side upper opening 46a is set in a shape that goes around the oxidant gas inlet communication hole 26a and the recess 27a. The anode-side upper opening 48a is set in a shape that goes around the fuel gas inlet communication hole 28a and the recess 29a.

  The drainage member 44 has a cathode side lower opening (lower opening) 46b communicating with the oxidant gas outlet communication hole 26b on the lower side and an anode side lower opening (lower opening) communicating with the fuel gas outlet communication hole 28b. 48b.

  A plurality of cathode-side drain passages (drain passages) 50 that communicate with the cathode-side upper opening 46a and the cathode-side lower opening 46b on one surface 44a of the drainage member 44 and are inclined in the direction of gravity. Is formed. The other surface 44b of the drainage member 44 communicates with the anode-side upper opening 48a and the anode-side lower opening 48b, and a plurality of anode-side drain channels (drain channels) 52 that incline toward the direction of gravity. Is formed.

  As shown in FIG. 1, the oxidant gas inlet communication hole 26a, the fuel gas inlet communication hole 28a, the oxidant gas outlet communication hole 26b, and the fuel gas outlet communication hole 28b are formed in the first end plate 18a. Although not shown, the second end plate 18b is formed with a cooling medium inlet communication hole 30a and a cooling medium outlet communication hole 30b.

  The first end plate 18 a and the second end plate 18 b are clamped and held in the stacking direction via a plurality of, for example, four tie rods 54, thereby forming the fuel cell stack 10.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 3, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 28a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 30a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26a. The oxidant gas is supplied to the cathode side electrode 40 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow C direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the second separator 24 from the fuel gas inlet communication hole 28a. The fuel gas is supplied to the anode side electrode 42 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow C direction.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 42 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas that is supplied to the cathode side electrode 40 and partially consumed is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b. On the other hand, the fuel gas partially consumed by being supplied to the anode side electrode 42 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b. Although not shown, the partially consumed fuel gas is sucked into the ejector from the return flow path and supplied to the fuel cell stack 10.

  The cooling medium supplied to each cooling medium inlet communication hole 30a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24 and then flows in the direction of arrow B. The cooling medium is discharged from each cooling medium outlet communication hole 30b after the electrolyte membrane / electrode structure 20 is cooled.

  In this case, the fuel cell stack 10 includes a plurality of fuel cells 12 stacked in the horizontal direction (arrow A direction), and the first end plate 18a and the second end plate 18b disposed at both ends in the stacking direction are tie rods. Fastened and held by 54. Therefore, as shown in FIG. 2, the fuel cell stack 10 is easily bent such that the intermediate portion in the stacking direction moves downward.

  Therefore, in the first embodiment, the drainage member 44 is disposed at an intermediate portion in the stacking direction of the fuel cell stack 10. For this reason, for example, the anode-side upper opening 48 a of the drainage member 44 is disposed at the intermediate portion in the stacking direction where the fuel gas inlet communication hole 28 a is at the lowest position due to the deflection of the fuel cell stack 10.

  As a result, the condensed water introduced into the fuel gas inlet communication hole 28a follows the inclination of the fuel gas inlet communication hole 28a, that is, from the first power generation cell group 12a to the drainage member 44 side, and the second power generation. The cell group 12b moves to the drainage member 44 side.

  Condensed water that has moved from both sides in the direction of arrow A toward the drainage member 44 along the inclination of the fuel gas inlet communication hole 28a is introduced into the anode-side upper opening 48a of the drainage member 44 from the recesses 29a that communicate with each other. .

  The upper side of the anode-side drain channel 52 communicates with the anode-side upper opening 48a. Accordingly, the condensed water introduced into the anode-side upper opening 48a moves in the direction of gravity along the anode-side drain channel 52 and then flows into the anode-side lower opening 48b. The anode side lower opening 48b communicates with the fuel gas outlet communication hole 28b. For this reason, the condensed water is discharged to the first end plate 18a together with the discharged fuel gas from the fuel gas outlet communication hole 28b toward the first end plate 18a.

  As described above, the condensed water introduced along with the fuel gas into the fuel gas inlet communication hole 28a in the fuel cell stack 10 is recessed along the slope of the bottom surface 29 that forms the fuel gas inlet communication hole 28a. And further easily and smoothly move to the drainage member 44 side through the recess 29a. The condensed water is discharged from the anode-side upper opening 48 a of the drainage member 44 in the gravity direction along the plurality of anode-side drain channels 52.

  Thereby, in 1st Embodiment, the effect that it becomes possible to perform favorable waste_water | drain processing reliably with a simple structure using the bending of the whole fuel cell stack 10 is acquired.

  On the other hand, when condensed water is introduced into the oxidant gas inlet communication hole 26a along with the oxidant gas, the condensed water moves to the recess 27a along the inclination of the bottom surface 27 of the oxidant gas inlet communication hole 26a. To do. Further, the condensed water easily and surely moves along the communication shape of the recesses 27 a toward the drainage member 44, and extends along the plurality of cathode-side drain channels 50 from the cathode-side upper opening 46 a of the drainage member 44. Are discharged in the direction of gravity. Therefore, it is possible to reliably perform a good wastewater treatment with a simple configuration by utilizing the deflection of the entire fuel cell stack 10.

  FIG. 6 is an exploded perspective view of a main part of a fuel cell stack 60 according to the second embodiment of the present invention.

  The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the fuel cell stack 60, the drainage member 62 is disposed in an intermediate portion in the stacking direction of the plurality of fuel cells 12, that is, a portion that is easily bent downward of the fuel cell stack 60. The drainage member 62 communicates with the oxidant gas outlet communication hole 26b, communicates with the cathode side lower opening 46b1 that opens below the oxidant gas outlet communication hole 26b, the fuel gas outlet communication hole 28b, and An anode-side lower opening 48b1 that opens below the fuel gas outlet communication hole 28b is provided (see FIGS. 7 and 8).

  A plurality of cathode side drain ports 64 communicating with the cathode side lower opening 46b1 are formed on the surface 44a, and the cathode side drain ports 64 communicate with the outside of the fuel cell stack 60 via the cathode side drain pipe 66. . Although not shown, the cathode-side drain pipe 66 is provided with an on-off valve or the like as necessary, and wastewater treatment is automatically performed.

  A plurality of anode-side drain ports 68 communicating with the anode-side lower opening 48b1 are formed on the surface 44b of the drainage member 62. An anode side drain pipe 70 is connected to the anode side drain port 68, and the anode side drain pipe 70 is disposed outside the fuel cell stack 60.

  In the second embodiment configured as described above, the lower side of the drainage member 62 has a cathode-side lower opening 46b1 that opens below the oxidant gas outlet communication hole 26b and a fuel gas outlet communication hole 28b. An anode-side lower opening 48b1 that opens downward is provided.

  Accordingly, the condensed water flowing into the drainage member 62 along the inclination of the oxidant gas outlet communication hole 26b and the condensed water flowing into the drainage member 62 along the inclination of the fuel gas outlet communication hole 28b open downward. It is reliably stored in the cathode side lower opening 46b1 and the anode side lower opening 48b1.

  Further, the condensed water staying in the cathode side lower opening 46b1 and the anode side lower opening 48b1 is externally supplied from the cathode side drain port 64 and the anode side drain port 68 through the cathode side drain pipe 66 and the anode side drain pipe 70, respectively. Have been discharged. For this reason, in the drainage member 62, the condensed water does not stay more than necessary, and the drainage performance of the condensed water is further improved. In addition, the same effect as in the first embodiment is obtained. It is done.

DESCRIPTION OF SYMBOLS 10, 60 ... Fuel cell stack 12 ... Fuel cell 12a, 12b ... Power generation cell group 14a, 14b ... Terminal plate 16a, 16b ... Insulating plate 18a, 18b ... End plate 20 ... Electrolyte membrane electrode assembly 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication holes 27, 29 ... Bottom surface 27a, 29a ... Recess 28a ... Fuel gas inlet communication hole 28b ... Fuel gas outlet communication hole 30a ... Cooling medium inlet communication hole 30b ... Cooling medium Outlet communication hole 32 ... oxidant gas flow path 34 ... fuel gas flow path 36 ... cooling medium flow path 38 ... solid polymer electrolyte membrane 40 ... cathode side electrode 42 ... anode side electrodes 44, 62 ... drainage member 46a ... upper cathode side Openings 46b, 46b1 ... Cathode-side lower opening 48a ... Anode-side upper openings 48b, 48b1 ... A Over de side lower opening 50 ... cathode-side drain passage 52 ... anode drain channel 54 ... tie rod 64 ... cathode side drain port 66 ... cathode-side drain pipe 68 ... anode drain opening 70 ... anode drain pipe

Claims (6)

A plurality of power generation cells are stacked in a horizontal direction, end plates are disposed at both ends in the stacking direction, and a reaction gas supply communication hole that supplies at least a reaction gas that is a fuel gas or an oxidant gas along the stacking direction; The reaction gas discharge communication hole for discharging the reaction gas is a fuel cell stack provided at the top and bottom,
A drainage member disposed only in the intermediate part of the power generation cell in the stacking direction
The fuel cell stack, wherein the drainage member is provided with a drain flow path for discharging moisture contained in the reaction gas supplied to the reaction gas supply communication hole along the direction of gravity. 2. The fuel cell stack according to claim 1, wherein the drainage member is provided with an upper opening communicating with the reaction gas supply communication hole on an upper side,
While providing a lower opening that communicates with the reactive gas discharge communication hole on the lower side,
The fuel cell stack, wherein the drain channel that communicates the upper opening and the lower opening is provided on at least one surface. 3. The fuel cell stack according to claim 2, wherein the drainage member has a cathode-side upper opening that is the upper opening that communicates with the oxidant gas inlet communication hole that is the reaction gas supply communication hole on the upper side, and the reaction. An anode-side upper opening that is the upper opening that communicates with the fuel gas inlet communication hole that is a gas supply communication hole;
The cathode side lower opening that is the lower opening communicating with the oxidant gas outlet communication hole that is the reaction gas discharge communication hole on the lower side, and the fuel gas outlet communication hole that is the reaction gas discharge communication hole Provide the anode side lower opening that is the lower opening,
On one surface of the drainage member, a cathode-side drain channel that is the drain channel communicating with the cathode-side upper opening and the cathode-side lower opening is formed,
A fuel cell stack, characterized in that an anode side drain channel, which is the drain channel communicating with the anode side upper opening and the anode side lower opening, is formed on the other surface of the drainage member. .   4. The fuel cell stack according to claim 2 or 3, wherein the lower opening is provided with a drain outlet located below the reaction gas discharge communication hole. 5. The fuel cell stack according to claim 1, wherein a first power generation cell group in which a plurality of the power generation cells are stacked is provided between the drainage member and one of the end plates. on the other hand,
Between the drainage member and the other end plate, a second power generation cell group in which a plurality of the power generation cells are stacked is provided,
The fuel cell stack is characterized in that moisture is supplied to the drainage member from the reaction gas supply communication hole of the first power generation cell group and the reaction gas supply communication hole of the second power generation cell group. A plurality of power generation cells are stacked in a horizontal direction, end plates are disposed at both ends in the stacking direction, and a reaction gas supply communication hole that supplies at least a reaction gas that is a fuel gas or an oxidant gas along the stacking direction; The reaction gas discharge communication hole for discharging the reaction gas is a fuel cell stack provided at the top and bottom,
A drainage member disposed at an intermediate portion in the stacking direction of the power generation cell,
The drainage member is provided with an upper opening communicating with the reaction gas supply communication hole on the upper side,
A lower opening communicating with the reaction gas discharge communication hole is provided on the lower side, and the lower opening is provided with a drain port located below the reaction gas discharge communication hole,
At least one surface communicates the upper opening and the lower opening, and drains the moisture contained in the reaction gas supplied to the reaction gas supply communication hole along the direction of gravity. A fuel cell stack.

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