JP2008293808A - Separator and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce temperature difference between an oxidizing gas exhaust manifold and a power generation body in a fuel cell. <P>SOLUTION: The fuel cell is configured by alternately stacking a separator and a power generation module including the power generation body. The separator includes: an oxidizing gas exhaust manifold hole for exhausting oxidizing gas; and a power generation region which is a region overlapping with the power generation body in the stacking direction in stacking and includes a part positioning on at least one side of the oxidizing gas exhaust manifold and a part positioning on the opposite side to the one side of the oxidizing gas exhaust manifold hole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a separator for a fuel cell and a fuel cell using such a separator, and more particularly to temperature management of the fuel cell.

  In a fuel cell, for example, a polymer electrolyte fuel cell, a reactive gas (a fuel gas containing hydrogen and an oxidizing gas containing oxygen) is respectively applied to two electrodes (a fuel electrode and an oxygen electrode) facing each other with an electrolyte membrane interposed therebetween. By supplying and causing an electrochemical reaction, the chemical energy of the substance is directly converted into electrical energy. As a main structure of such a fuel cell, a so-called stack structure in which a power generator including a substantially flat electrolyte membrane and a separator are alternately stacked and fastened in a stacking direction is known (for example, Patent Documents). 1).

Japanese Patent Laid-Open No. 11-15728 JP 2006-173056 A

  By the way, since the electrochemical reaction in the fuel cell is an exothermic reaction, temperature management during operation of the fuel cell is one important technical theme. In the above prior art, an oxidizing gas discharge manifold for discharging the oxidizing gas is disposed on the outer peripheral edge of the separator. For this reason, the temperature difference from the oxidizing gas discharge manifold may be increased. As a result, there is a possibility that moisture is condensed and condensed in the oxidizing gas discharge manifold. Condensed / condensed water may hinder the flow of the oxidizing gas and cause deterioration of the performance of the fuel cell.

  The present invention has been made to solve the above-described problems, and an object thereof is to suppress a temperature difference between the oxidizing gas discharge manifold and the power generation body.

  In order to solve the above problems, a first aspect of the present invention provides a separator that is alternately stacked with a power generation module including a power generation body to constitute a fuel cell. The separator according to the first aspect includes an oxidizing gas discharge manifold hole for discharging oxidizing gas, and a region that overlaps with the power generator in the stacking direction when stacked, and at least one side of the oxidizing gas discharge manifold hole And a power generation region including a portion located on the opposite side of the one side of the oxidizing gas discharge manifold hole.

  In the separator according to the first aspect, the oxidizing gas discharge manifold is sandwiched between power generation regions overlapping with the power generation body. Therefore, if the separator according to the first aspect is used, in the fuel cell, the temperature difference between the portion overlapping the power generator and the stacking direction and the oxidizing gas discharge manifold can be reduced. As a result, it is possible to suppress problems caused by such temperature differences.

  A second aspect of the present invention provides a separator that is alternately stacked with a power generation module including a power generation body to constitute a fuel cell. The separator according to the second aspect is a manifold hole for exhausting the oxidizing gas, and at least in one direction, the oxidizing gas exhaust manifold hole disposed at a substantially central portion of the separator, and the oxidizing gas exhaust manifold hole And a power generation region that overlaps with the power generator when stacked.

  In the separator according to the second aspect, the oxidizing gas discharge manifold can take a distance from the outside in at least one direction, and heat radiation from the oxidizing gas discharge manifold to the outside can be suppressed. Therefore, if the separator according to the first aspect is used, in the fuel cell, the temperature difference between the portion overlapping the power generator and the stacking direction and the oxidizing gas discharge manifold can be reduced. As a result, it is possible to suppress problems caused by such temperature differences.

  In the separator according to the aspect described above, the power generation region includes a first region adjacent to one side of the oxidizing gas discharge manifold hole and a second adjacent to the opposite side of the one side of the oxidizing gas discharge manifold hole. May be included. In this way, by providing a plurality of power generation regions and sandwiching the oxidizing gas discharge manifold from both sides, the temperature difference between the portion overlapping the power generator and the stacking direction and the oxidizing gas discharge manifold can be reduced.

  The separator according to the above aspect further includes a manifold hole for supplying an oxidizing gas, the first oxidizing gas supply manifold hole adjacent to the first region opposite to the oxidizing gas discharge manifold hole. And a second oxidant gas supply manifold hole for supplying an oxidant gas adjacent to the second region on the opposite side of the oxidant gas discharge manifold hole. . In this way, in the separator, the oxidizing gas supply manifold can be arranged on the outside and the oxidizing gas discharge manifold can be arranged on the inside, so that a decrease in the temperature of the oxidizing gas discharge manifold can be suppressed. As a result, the temperature difference between the portion overlapping the power generation body in the stacking direction and the oxidizing gas discharge manifold can be further reduced.

  The present invention can be realized in various aspects in addition to the above aspect. For example, the present invention provides a fuel cell configured by alternately laminating the separator according to the above aspect and a power generation module including a power generator, a fuel cell system including the fuel cell, a vehicle equipped with the fuel cell, and the like. This is realized as a device invention.

  Hereinafter, a fuel cell according to an embodiment of the present invention will be described based on examples with reference to the drawings.

A. Example:
-Structure of fuel cell The structure of the fuel cell which concerns on the Example of this invention is demonstrated with reference to FIGS. 1 and 2 are diagrams showing an external configuration of a fuel cell according to an embodiment. FIG. 3 and FIG. 4 are diagrams for explaining a membrane electrode assembly in an example. FIG. 3 shows a plan view of the membrane electrode assembly, and FIGS. 4A to 4B show an AA section and a BB section in FIG. 3, respectively. 5 and 6 are diagrams showing the configuration of the separator in the example. FIG. 5 shows a plan view of the separator, and FIG. 6 shows a plan view of each plate constituting the separator.

  As shown in FIG. 1, the fuel cell 100 has a stack structure in which a plurality of membrane electrode assemblies 200 and a plurality of separators 600 are alternately stacked. As shown in FIG. 2, an anode side porous body 840 or a cathode side porous body 850 is disposed between the separator 600 and the membrane electrode assembly 200. The anode-side porous body 840 may be configured integrally with the separator 600 as in the example shown in FIG. 2 or may be configured as a separate body.

  The anode side porous body 840 is disposed between the anode side of the separator 600 and the anode side of the membrane electrode assembly 200, and the cathode side porous body 850 includes the cathode side of the separator 600 and the cathode side of the membrane electrode assembly 200. It is arranged between. The anode side porous body 840 and the cathode side porous body 850 are formed of a porous material having gas diffusibility and conductivity such as a metal porous body. As the anode side porous body 840 and the cathode side porous body 850, those having higher porosity and lower gas flow resistance than those of the anode side diffusion layer 820 and cathode side diffusion layer 830, which will be described later, are used. Functions as a flow path for fluid flow.

  As shown in FIG. 1, the fuel cell 100 is supplied with oxidizing gas supply manifolds 110a to 110c to which oxidizing gas is supplied, oxidizing gas discharge manifolds 120a to 120c for discharging oxidizing gas, and fuel gas to which fuel gas is supplied. Supply manifolds 130a and 130b, a fuel gas discharge manifold 140 for discharging fuel gas, cooling medium supply manifolds 150a and 150b for supplying a cooling medium, and cooling medium discharge manifolds 160a and 160b for discharging a cooling medium are provided. ing. These manifolds have a tubular shape formed in the stacking direction of the fuel cells 100. Note that air is generally used as the oxidizing gas, and hydrogen is generally used as the fuel gas. Further, both the oxidizing gas and the fuel gas are also called reaction gases. As the cooling medium, water, antifreeze water such as ethylene glycol, air, or the like can be used.

  The configuration of the membrane electrode assembly 200 will be described with reference to FIGS. 3 and 4. As shown in FIGS. 3 and 4, the membrane electrode assembly 200 includes two power generation units 800 a and 800 b and a non-power generation unit 700.

  As shown in FIG. 4, the power generation unit 800 a is configured by laminating a power generation body 810, an anode side diffusion layer 820, and a cathode side diffusion layer 830. In FIG. 3, the outer peripheral ends of the cathode side diffusion layer 830 and the anode side diffusion layer 820 are indicated by wavy lines. The portions inside the wavy line are a power generation unit 800a and a power generation unit 800b where power generation is performed. The shape seen from the stacking direction of the power generation unit 800a and the power generation unit 800b is a substantially rectangular shape having a short side and a long side.

  In this embodiment, the power generator 810 is an ion exchange membrane in which a catalyst layer as a cathode is applied on one surface and a catalyst layer as an anode is applied on the other surface (illustration of the catalyst layer is omitted). The ion exchange membrane is formed of a fluorine-based resin material or a hydrocarbon-based resin material and has good ionic conductivity in a wet state. The catalyst layer includes, for example, platinum or an alloy made of platinum and another metal.

  The anode-side diffusion layer 820 is disposed in contact with the anode-side surface of the power generation body 810, and the cathode-side diffusion layer 830 is disposed in contact with the cathode-side surface of the power generation body 810. The anode side diffusion layer 820 and the cathode side diffusion layer 830 are formed of, for example, carbon cloth woven with yarns made of carbon fibers, carbon paper, or carbon felt.

  Since the power generation unit 800b has the same configuration as that of the power generation unit 800a described above, the same components are denoted by the same reference numerals in the following description, and detailed description thereof is omitted.

  The non-power generation unit 700 is arranged over the entire circumference in the surface direction of the power generation unit 800a and the power generation unit 800b. Specifically, the two power generation units 800a and 800b are arranged side by side in the Y-axis direction (vertical direction) in FIG. 3, and the entire circumference of the two power generation units 800a and 800b arranged, and A non-power generation unit 700 is formed between the power generation unit 800a and the power generation unit 800b. The non-power generation unit 700 includes two sealing members bonded in an airtight manner, that is, a first member 700a and a second member 700b. The first member 700a and the second member 700b are configured so as to sandwich the outer peripheral ends of the power generator 810, the cathode side diffusion layer 830, and the anode side diffusion layer 820. Thereby, mixing of the reaction gas between the anode side and the cathode side of the power generation body 810 is suppressed. The first member 700a and the second member 700b are formed of a material having insulation properties, gas impermeability, and heat resistance in the operating temperature range of the fuel cell, for example, a resin material such as a thermosetting resin or a general-purpose plastic. .

  As shown by cross-hatching in FIG. 3, the non-power generation unit 700 is formed with through holes (manifold holes) corresponding to the manifolds 110a to 160b in FIG. The non-power generation unit 700 is hermetically bonded to the separators 600 adjacent to each other on both sides (not shown) to seal between the separators 600 to prevent leakage of reaction gas (hydrogen and air in this embodiment) and cooling water. To prevent. Specifically, the entire peripheries of the power generation units 800a and 800b and the entire peripheries of the individual manifold holes (except for a flow path portion for supplying / discharging reaction gas described later) are sealed.

  Among these manifold holes, the oxidizing gas discharge manifolds 120a to 120c are disposed between the power generation unit 800a and the power generation unit 800b. The oxidizing gas discharge manifolds 120a to 120b are arranged along the long side on the lower side (Y-axis positive direction side) in FIG. 3 of the power generation unit 800a and the long side on the upper side (Y-axis negative direction side) of the power generation unit 800b. It is formed over almost the entire length of the long side.

  Among the manifold holes, manifolds other than the three oxidizing gas discharge manifolds 120 a to 120 c described above are formed along the outer peripheral edge of the membrane electrode assembly 200. Specifically, the three oxidizing gas supply manifolds 110a to 110c are arranged along the upper side (Y-axis negative direction side) of the membrane electrode assembly 200 in FIG. These oxidizing gas supply manifolds 110a to 110c are located on the opposite side to the oxidizing gas discharge manifolds 120a to 120c, respectively, with respect to the power generation unit 800a. The other three oxidizing gas supply manifolds 110d to 110f are arranged along the lower side (Y-axis positive direction side) of the membrane electrode assembly 200 in FIG. These oxidizing gas supply manifolds 110d to 110f are located on the opposite side to the oxidizing gas discharge manifolds 120a to 120c, respectively, with respect to the power generation unit 800b.

  The two cooling medium supply manifolds 150a and 150b are disposed along the left side (X-axis negative direction side) of the membrane electrode assembly 200 in FIG. Among these, the cooling medium supply manifold 150a is formed along the short left side of the power generation unit 800a over substantially the entire length of the side. The cooling medium supply manifold 150b is formed along the short left side of the power generation unit 800a over substantially the entire length of the side.

  The two cooling medium discharge manifolds 160a and 160b are arranged along the short side on the right side (X-axis positive direction side) of the membrane electrode assembly 200 in FIG. Among these, the cooling medium discharge manifold 160a is formed along the short side on the right side of the power generation unit 800a over substantially the entire length of the side. The cooling medium discharge manifold 160b is formed along the short side on the right side of the laminated member 800b over substantially the entire length of the side.

  The two fuel gas supply manifolds 130a and 130b are arranged at the upper left corner (X-axis negative direction, Y-axis negative direction corner) and lower-left corner (X-axis negative direction, Y-axis positive direction) of the membrane electrode assembly 200 in FIG. At the corners). The fuel gas supply manifold 130a supplies fuel gas to the power generation body 810 of the power generation unit 800a, and the fuel gas supply manifold 130b supplies fuel gas to the power generation body 810 of the power generation unit 800b.

  The fuel gas discharge manifold 140 is disposed between the cooling medium discharge manifold 160a and the cooling medium discharge manifold 160b at the center of the right side of the membrane electrode assembly 200 in FIG.

  The non-power generation unit 700 further includes two fuel gas supply channels 630, two fuel gas discharge channels 640, a large number of oxidizing gas supply channels 650, and a large number of channels for supplying / discharging reactant gases. The oxidizing gas discharge channel 660 is formed. These flow paths 630 to 640 are formed in a groove shape not penetrating through the non-power generation unit 700 as shown in FIG. 4A at the position indicated by single hatching in FIG. 3. The fuel gas supply flow path 630 and the fuel gas discharge flow path 640 are formed on the back side in FIG. 3, that is, the anode side of the non-power generation unit 700, and the oxidizing gas supply flow path 650 and the oxidizing gas discharge flow path 660 are as shown in FIG. Is formed on the cathode side of the non-power generation unit 700.

  One fuel gas supply channel 630 communicates the fuel gas supply manifold 130a and the anode-side porous body 840 that overlaps the power generation unit 800a, and the other fuel gas supply channel 630 includes the fuel gas supply manifold 130b, The anode-side porous body 840 that overlaps the power generation unit 800b is communicated. One fuel gas discharge channel 640 communicates the fuel gas discharge manifold 140 with the anode-side porous body 840 that overlaps the power generation unit 800a, and the other fuel gas discharge channel 640 includes the fuel gas discharge manifold 140, The anode-side porous body 840 that overlaps the power generation unit 800b is communicated.

  Part of the plurality of oxidizing gas supply channels 650 communicates the oxidizing gas supply manifolds 110a to 110c and the cathode-side porous body 850 that overlaps the power generation unit 800a. Another part of the plurality of oxidizing gas supply channels 650 communicates the oxidizing gas supply manifolds 110d to 110f and the cathode-side porous body 850 that overlaps the power generation unit 800b. A part of the oxidizing gas discharge channel 660 communicates with the oxidizing gas discharge manifolds 120a to 120c and the cathode-side porous body 850 overlapping the power generation unit 800a, and the other part includes the oxidizing gas discharge manifolds 120a to 120c, The cathode-side porous body 850 that overlaps the power generation unit 800b is communicated.

  Next, the configuration of the separator 600 will be described with reference to FIGS. The separator 600 includes an anode plate 300, a cathode plate 400, and an intermediate plate 500.

  6A to 6C show the shapes of the anode plate 300 (FIG. 6A), the cathode plate 400 (FIG. 6B), and the intermediate plate 500 (FIG. 6C) in the embodiment. It is explanatory drawing shown. Two regions DAa and DAb indicated by broken lines in each of the plates 300, 400, and 500 and the separator 600 indicate regions that overlap with the power generation units 800a and 800b, respectively.

  In the anode plate 300 and the cathode plate 400, manifold forming portions that penetrate the plates in the thickness direction are formed corresponding to the manifolds 110a to 160b in FIG.

  The intermediate plate 500 is formed with a manifold forming portion that penetrates the intermediate plate 500 in the thickness direction corresponding to the manifolds 110a to 140 for supplying / discharging the reaction gas (oxidizing gas or fuel gas) shown in FIG. ing.

  The intermediate plate 500 further includes a plurality of cooling medium flow path forming portions 550. Each cooling medium flow path forming portion 550 has a long hole shape that crosses the power generation portions 800a and 800b in the left-right direction in FIG. 3, and both ends thereof reach the outside of the power generation portions 800a and 800b. The cooling medium flow path forming unit 550 may be disposed over the entire power generation units 800a and 800b.

  FIG. 5 shows a front view of a separator 600 manufactured using each of the plates 300, 400, and 500 described above. The separator 600 is joined to both sides of the intermediate plate 500 so that the intermediate plate 500 is sandwiched between the anode plate 300 and the cathode plate 400, and is connected to the cooling medium supply manifolds 150a and 150b and the cooling medium discharge manifolds 160a and 160b in the intermediate plate 500. It is manufactured by punching a portion exposed in a corresponding region. As a method of joining the three plates, for example, thermocompression bonding, brazing, welding, or the like can be used. As a result, as shown by hatching in FIG. 5, when the fuel cell 100 is configured, a separator 600 having through portions for forming the manifolds shown in FIG. 1 and a plurality of cooling medium flow paths 670 is obtained. It is done. The cooling medium flow path 670 is an internal flow path passing through the inside of the separator 600 in the surface direction, and one end communicates with the cooling medium supply manifold 150a or 150b and the other end communicates with the cooling medium discharge manifold 160a or 160b.

  In the separator 600, the oxidizing gas discharge manifolds 120a to 120c are disposed between the power generation unit 800a and the power generation unit 800b. Among the manifold holes, manifolds other than the three oxidizing gas discharge manifolds 120 a to 120 c described above are formed along the outer peripheral edge of the separator 600. Specifically, the three oxidizing gas supply manifolds 110a to 110c are arranged along the upper side of the separator 600 in FIG. These oxidizing gas supply manifolds 110a to 110c are located on the opposite side to the oxidizing gas discharge manifolds 120a to 120c, respectively, with respect to the power generation unit 800a. The other three oxidizing gas supply manifolds 110d to 110f are arranged along the lower side (Y-axis positive direction side) of the separator 600 in FIG. These oxidizing gas supply manifolds 110d to 110f are located on the opposite side to the oxidizing gas discharge manifolds 120a to 120c, respectively, with respect to the power generation unit 800b.

  The two cooling medium supply manifolds 150a and 150b are arranged along the left side of the separator 600 in FIG. Among them, the cooling medium supply manifold 150a is formed along the left side of the power generation unit 800a over substantially the entire length of the side. The cooling medium supply manifold 150b is formed along the left side of the power generation unit 800a over substantially the entire length of the side.

  The two cooling medium discharge manifolds 160a and 160b are arranged along the right side of the separator 600 in FIG. Among these, the cooling medium discharge manifold 160a is formed along the right side of the power generation unit 800a over substantially the entire length of the side. The cooling medium discharge manifold 160b is formed along the right side of the power generation unit 800b over substantially the entire length of the side.

  The two fuel gas supply manifolds 130a and 130b are respectively arranged at the upper left corner and the lower left corner of the separator 600 in FIG. The fuel gas discharge manifold 140 is disposed between the cooling medium discharge manifold 160a and the cooling medium discharge manifold 160b at the center of the right side of the separator 600 in FIG.

-Operation | movement of fuel cell With reference to FIG. 7 and FIG. 8, operation | movement of the fuel cell 100 which concerns on an Example is demonstrated. FIG. 7 is an explanatory diagram showing the flow of the oxidizing gas. FIG. 8 is an explanatory diagram showing the flow of the cooling medium. 7 and 8, only one separator 600 and the porous bodies 840 and 850 arranged on both sides of the membrane electrode assembly 200 are shown in FIGS. 7 and 8. 7A, the upper half shows a cross-sectional view corresponding to the AA cross section in FIG. 3, and the lower half shows a cross section corresponding to the CC cross section in FIG. FIG. 7B shows a cross-sectional view corresponding to the DD cross section in FIG. 8, the left half shows a cross-sectional view corresponding to the EE cross section in FIG. 5, and the right half shows a cross sectional view corresponding to the FF cross section in FIG. 5.

  The fuel cell 100 generates power by supplying oxidizing gas to the oxidizing gas supply manifolds 110a to 110f and supplying fuel gas to the fuel gas supply manifolds 130a and 130b. In addition, the cooling medium is supplied to the cooling medium supply manifolds 150a and 150b to the fuel cell 100 during power generation in order to suppress the temperature rise of the fuel cell 100 due to heat generated by power generation.

The oxidant gas supplied to the three oxidant gas supply manifolds 110a to 110c passes through the oxidant gas supply channel 650 to the cathode-side porous body 850 that overlaps the power generation unit 800a as shown by arrows in FIG. Supplied. The oxidizing gas supplied to the cathode-side porous body 850 flows from the upper side to the lower side in FIG. 3 in the cathode-side porous body 850 that functions as a flow path for the oxidizing gas. Then, the oxidizing gas flows from the cathode-side porous body 850 into the oxidizing gas discharge channel 660, passes through the oxidizing gas discharge channel 660, and is discharged to the oxidizing gas discharge manifolds 120a to 120b. The oxidant gas supplied to the other three oxidant gas supply manifolds 110d to 110f passes through the oxidant gas supply channel 650 and overlaps with the power generation unit 800b as shown by arrows in FIG. 7B. 850. The oxidizing gas supplied to the cathode-side porous body 850 flows from the lower side to the upper side in FIG. 3 in the cathode-side porous body 850 that functions as a flow path for the oxidizing gas. Then, the oxidizing gas flows from the cathode-side porous body 850 into the oxidizing gas discharge channel 660, passes through the oxidizing gas discharge channel 660, and is discharged to the oxidizing gas discharge manifolds 120a to 120b. In both of the power generation units 800a and 800b, part of the oxidizing gas flowing through the cathode-side porous body 850 is diffused over the entire cathode-side diffusion layer 830 that is in contact with the cathode-side porous body 850. (For example, 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O).

Although illustration of the cross section is omitted, the fuel gas supplied to the fuel gas supply manifolds 130a and 130b passes through the fuel gas supply flow path 630 and overlaps with the power generation units 800a and 800b in the same manner as the oxidizing gas. 840, respectively. The fuel gas supplied to the anode side porous body 840 flows inside the anode side porous body 840 functioning as a flow path for the fuel gas. Then, the fuel gas flows from the anode side porous body 840 into the fuel gas discharge channel 640, passes through the fuel gas discharge channel 640, and is discharged to the fuel gas discharge manifold 140. A part of the fuel gas flowing through the anode-side porous body 840 diffuses over the entire anode-side diffusion layer 820 that is in contact with the anode-side porous body 840, and the anode reaction (for example, H ₂ → 2H ⁺ + 2e ⁻ ).

  The cooling medium supplied to the cooling medium supply manifolds 150 a and 150 b is supplied to the cooling medium flow path 670. The cooling medium supplied to the cooling medium flow path 670 flows from one end of the cooling medium flow path 670 to the other end, and is discharged to the cooling medium discharge manifolds 160a and 160b. While the cooling medium flows mainly in the vicinity of the power generation units 800a and 800b, the fuel cell is cooled by absorbing the heat of the power generation units 800a and 800b of the membrane electrode assembly 200 described above.

  According to the present embodiment described above, the temperature difference between the power generation units 800a and 800b in the fuel cell and the non-power generation unit 700 (for example, inside and around the oxidizing gas discharge manifolds 120a to 120c) can be reduced. FIG. 9 is an explanatory diagram showing a temperature distribution during power generation of the fuel cell. The graph shown in FIG. 9 shows the temperature of the separator 600 for each position Y on the line GG shown in FIG. Line M1 shows the temperature distribution when time M1 has elapsed since the start of power generation, and line M2 shows the temperature distribution when time M2 has elapsed since the start of power generation (M2> M1). As time elapses from the start of power generation, it can be seen that the temperatures of the power generation unit 800a and the power generation unit 800b rise due to reaction heat. As a result, the temperature difference between the power generation unit 800a and the power generation unit 800b and the outer periphery of the non-power generation unit 700 (for example, the region where the oxidizing gas supply manifolds 110a to 110f are formed) increases. However, the portion of the non-power generation unit 700 where the oxidizing gas discharge manifolds 120a to 120c are formed has a relatively high temperature. This is because 1) the portion where the oxidizing gas discharge manifolds 120a to 120c are formed is sandwiched between the two power generation units 800a and 800b having a high temperature, and 2) the oxidizing gas discharge manifolds 120a to 120c are formed. This is because the portion that is located is substantially in the center in the Y-axis direction and is not in contact with the outside, so that heat is not released to the outside. Thus, it can be seen that the temperature difference between the power generation units 800a and 800b in the fuel cell and the inside and the periphery of the oxidizing gas discharge manifolds 120a to 120c in the non-power generation unit 700 is reduced.

  Further, in this embodiment, the oxidizing gas discharge manifolds 120a to 120c have a long hole shape, and one power generation unit 800a is adjacent along one side of the two long sides of the long hole shape, and the other side. , Another power generation unit 800b is configured to be adjacent to each other. As a result, the entire oxidizing gas discharge manifolds 120a to 120c are relatively close to the high temperature power generation units 800a and 800b. As a result, the temperature difference between the power generation units 800a and 800b in the fuel cell and the inside and the periphery of the oxidizing gas discharge manifolds 120a to 120c can be further reduced.

As a result, it is possible to suppress condensation / condensation that occurs when moisture (product water or the like) contained in the oxidizing gas is rapidly cooled in the oxidizing gas discharge manifolds 120a to 120c. Condensed / condensed water hinders the smooth flow of oxidant gas, causing a decrease in power generation performance.

  In particular, when the outside temperature of the fuel cell is low (for example, below freezing point), the temperature difference between the power generation units 800a and 800b and the inside of the oxidizing gas discharge manifolds 120a to 120c tends to be large, so the effect is great. In addition, it is desired to reduce the thickness of the separator 600 because of a demand for miniaturization of the fuel cell 100. However, when the separator 600 becomes thinner, the thermal conductivity in the surface direction deteriorates. For this reason, the thinner the separator 600, the greater the effect because the temperature difference between the portion overlapping the power generation body in the stacking direction and the inside of the oxidizing gas discharge manifolds 120a and 120b tends to increase.

  The oxidizing gas discharge manifolds 120a to 120c are provided over substantially the entire length of one long side of the rectangular power generation unit 800a, and the oxidizing gas supply manifolds 110a to 110c are approximately the entire length of the other long side of the power generation unit 800a. Are provided. As a result, the oxidant gas flowing from the oxidant gas supply manifolds 110a to 110c to the oxidant gas discharge manifolds 120a to 120c is more evenly distributed throughout the power generation unit 800a. Similarly, the oxidizing gas discharge manifolds 120a to 120c are provided over substantially the entire length of one long side of the rectangular power generation unit 800b, and the oxidizing gas supply manifolds 110d to 110f are approximately the other long side of the power generation unit 800b. It is provided over the entire length. As a result, the oxidant gas flowing from the oxidant gas supply manifolds 110d to 110f to the oxidant gas discharge manifolds 120a to 120c is more evenly distributed throughout the power generation unit 800b.

On the other hand, the fuel gas supply manifolds 130a and 130b and the fuel gas discharge manifold 140 are smaller than the manifold for oxidizing gas, and are not formed over the entire length of the power generation units 800a and 800b. Hydrogen, the fuel gas, has a higher diffusion rate than oxygen in the air, the oxidizing gas (the diffusion rate mainly depends on the diffusion coefficient and concentration gradient. Hydrogen has a diffusion coefficient about four times that of oxygen. The fuel gas uses pure hydrogen (hydrogen concentration of about 100%), whereas the oxidizing gas uses air (oxygen concentration of about 20%). It can be seen that it is considerably lower than hydrogen in the gas.) For this reason, if fuel gas is supplied from a part of one side of the power generation units 800a and 800b, hydrogen necessary for the cell reaction can be sufficiently supplied. In other words, since the electrochemical reaction of the fuel cell has a slow diffusion rate of oxygen molecules, generally, the reaction at the three-phase interface of the cathode electrode (2H ⁺ + 2e ⁻ (1/2) O ₂ → H ₂ O) It is rate-limited. Therefore, the flow path arrangement with an emphasis on the supply performance of the oxidizing gas leads to further improvement in battery performance.

B. Variation:
In the above embodiment, the oxidizing gas discharge manifolds 120a to 120c are sandwiched between the two power generation units 800a and 800b, and the oxidizing gas discharge manifolds 120a to 120c are disposed in the center portion of the separator 600 in the Y-axis direction in FIG. However, other configurations may be used. For example, an oxidizing gas discharge manifold may be provided near the center of the circular power generation unit. Generally speaking, the power generation section preferably includes at least a portion located on one side of the oxidizing gas discharge manifold and a portion located on the opposite side of the one side of the oxidizing gas discharge manifold hole. Moreover, it is preferable that the oxidizing gas discharge manifold is located at a substantially central portion of the separator in at least one of the directions along the separator surface (direction perpendicular to the stacking direction).

  In the said Example, although the material of each member of the electric power generation parts 800a and 800b and each member of the separator 600 is specified, it is not limited to these materials, A proper various material can be used. For example, the anode-side porous body 840 and the cathode-side porous body 850 are formed using a metal porous body, but may be formed using other materials such as a carbon porous body. In addition, the separator 600 is formed using a metal, but other materials such as carbon may be used.

  In the above embodiment, the separator 600 has a structure in which three layers of metal plates are laminated, and the portions corresponding to the power generation portions 800a and 800b are flat. However, instead of this, other arbitrary shapes and Is possible. Specifically, a separator (for example, made of carbon) in which a groove-like reaction gas flow path is formed on the surface corresponding to the power generation unit may be employed, or a reaction gas may be provided in a portion corresponding to the power generation unit. You may employ | adopt the separator (For example, produced by press-molding a metal plate) which has a corrugated plate shape which functions as a flow path.

  Moreover, in the said Example, although the anode side porous body 840 and the cathode side porous body 850 are provided, it is not restricted to this. For example, in the case of using a separator in which a reaction gas channel is formed or a separator having a corrugated plate functioning as a reaction gas channel, the anode side and cathode side porous bodies may be omitted.

  As mentioned above, although the Example and modification of this invention were demonstrated, this invention is not limited to these Example and modification at all, and implementation in a various aspect is possible within the range which does not deviate from the summary. It is.

It is the 1st figure which shows the external appearance structure of the fuel cell which concerns on an Example. It is a 2nd figure which shows the external appearance structure of the fuel cell which concerns on an Example. It is a 1st figure explaining the membrane electrode assembly in an Example. It is a 2nd figure explaining the membrane electrode assembly in an Example. It is a 1st figure which shows the structure of the separator in an Example. It is a 2nd figure which shows the structure of the separator in an Example. It is explanatory drawing which shows the flow of oxidizing gas. It is explanatory drawing which shows the flow of a cooling medium. It is explanatory drawing which shows the temperature distribution during the electric power generation of a fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Fuel cell 110a-110f ... Oxidation gas supply manifold 120a-120c ... Oxidation gas discharge manifold 130a, 130b ... Fuel gas supply manifold 140 ... Fuel gas discharge manifold 150a, 150b ... Coolant supply manifold 160a, 160b ... Coolant discharge manifold DESCRIPTION OF SYMBOLS 200 ... Power generation module 300 ... Anode plate 400 ... Cathode plate 500 ... Intermediate plate 600 ... Separator 700 ... Non power generation part 800a, 820b ... Power generation part 810 ... Power generation body 820 ... Anode side diffusion layer 830 ... Cathode side diffusion layer 830 ... Anode side Diffusion layer 840 ... Anode-side porous body 850 ... Cathode-side porous body

Claims (5)

A separator that is alternately stacked with a power generation module including a power generation body to constitute a fuel cell,
An oxidizing gas discharge manifold hole for discharging the oxidizing gas;
A region that overlaps with the power generation body in the stacking direction at the time of stacking, at least a portion positioned on one side of the oxidizing gas discharge manifold hole, and a portion positioned on the opposite side of the one side of the oxidizing gas discharge manifold hole Including a power generation area, and
A separator comprising: A separator that is alternately stacked with a power generation module including a power generation body to constitute a fuel cell,
A manifold hole for exhausting the oxidizing gas, the oxidizing gas exhaust manifold hole disposed at a substantially central portion of the separator in at least one direction;
A power generation region that is disposed at a position different from the oxidizing gas discharge manifold hole and overlaps the power generation body when stacked,
A separator comprising: The separator according to claim 1 or 2,
The power generation region includes a first region adjacent to one side of the oxidizing gas discharge manifold hole and a second region adjacent to the opposite side of the one side of the oxidizing gas discharge manifold hole. The separator according to claim 3 further includes:
A manifold hole for supplying an oxidizing gas, the first oxidizing gas supply manifold hole adjacent to the first region opposite to the oxidizing gas discharge manifold hole;
A manifold hole for supplying an oxidant gas, a second oxidant gas supply manifold hole adjacent to the second region opposite to the oxidant gas discharge manifold hole;
A separator comprising:   A fuel cell configured by alternately stacking the separator according to any one of claims 1 to 4 and a power generation module including the power generation body.

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