JP2008198386A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a fuel cell formed of an electrolyte member to efficiently and stably perform humidification of oxidizing gas. <P>SOLUTION: For the fuel cell provided with an oxidizing gas supply channel 11e supplying oxidizing gas in the cell, and a fuel gas supply channel 11d supplying fuel gas in the cell, a power generating part carrying out power generation by electrochemical reaction is equipped with a first power generating area 11a where an anode side catalyst layer for the electrochemical reaction has a given thickness at a site having the fuel gas supplied from the fuel gas supply channel, and a second power generating area 11b having an anode side catalyst layer thinner than the given thickness. The fuel gas supply channel 11d and the oxidizing gas supply channel 11e are arranged in opposition to the power generating part so that a given substance in the fuel gas supply channel 11d can move to an upstream site of the oxidizing gas supply channel 11e, through the second power generating area 11b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel cell that generates power by an electrochemical reaction between a fuel gas and an oxidizing gas.

  In a conventional electrolyte fuel cell, a proton conductive electrolyte member is used. However, since the member generally exhibits proton conductivity in a state of containing moisture, in order to maintain the power generation performance of the fuel cell. The electrolyte member must always contain water. However, since a large amount of oxidizing gas (air) is supplied to the fuel cell, drying of the electrolyte member becomes remarkable particularly on the cathode side, which is one factor that reduces the power generation performance of the fuel cell.

  Therefore, a technique for exchanging water vapor between the cathode off-gas containing the water vapor generated by the electrochemical reaction in the fuel cell and the oxidizing gas, humidifying the oxidizing gas, and providing a device for performing this water vapor exchange adjacent to the fuel cell. Is disclosed (for example, see Patent Document 1). In this technique, moisture generated in the fuel cell can be added to the oxidizing gas at a relatively high temperature.

Further, as a method of humidifying the oxidizing gas, the hydrogen in the anode off-gas that has been discharged as residual hydrogen without being subjected to the electrochemical reaction in the fuel cell is recycled to the oxidizing gas, and the Pt catalyst at the cathode of the fuel cell is A technique for humidifying an oxidizing gas by using the hydrogen to burn is disclosed (see, for example, Patent Document 2). This technique is environmentally preferable because there is no need to release residual hydrogen to the outside of the fuel cell.
JP 2000-3720 A JP-A-11-185782 JP 2006-40563 A

  In a fuel cell formed of an electrolyte member, when the electrolyte member is dried, power generation performance as a fuel cell is degraded. And since this electrolyte member functions as an electrolyte in a state containing moisture, in order to generate power by the fuel cell, it is necessary to humidify the electrolyte member with moisture at a temperature about the operating temperature of the fuel cell.

  However, when a humidifier that supplies moisture to the oxidizing gas is provided separately from the fuel cell, space is required for the piping, etc., and in the piping, high-temperature moisture is cooled and condensed to liquid water, which is efficient. It is difficult to humidify the oxidizing gas. In addition, in humidifying the oxidizing gas using hydrogen in the anode off gas, the amount of residual hydrogen varies depending on the operating state of the fuel cell, and it is difficult to accurately control the amount. Therefore, it is difficult to stably humidify the oxidizing gas.

  The present invention has been made in view of the above problems, and an object thereof is to enable humidification of an oxidizing gas efficiently and stably in a fuel cell formed of an electrolyte member.

In the present invention, in order to solve the above problems, the oxidizing gas is humidified in the fuel cell. In other words, the water generated by the electrochemical reaction in the fuel cell, which has penetrated into the fuel gas and hydrogen in the fuel gas, can be generated directly by the electrochemical reaction, particularly by efficiently transferring it to the oxidizing gas. It is possible to efficiently humidify the electrolyte member in the cell as a whole by moving it to the upstream side of the oxidizing gas where moisture is unlikely to exist.

  Therefore, more specifically, the present invention is a fuel cell that generates electric power by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen in the cell, and the oxidizing gas is supplied into the cell. An oxidizing gas supply passage, a fuel gas supply passage for supplying the fuel gas into the cell, an electrolyte member formed in the cell, and supplied from the oxidizing gas supply passage and the fuel gas supply A power generation unit that generates power by an electrochemical reaction with fuel gas supplied from the passage, wherein the power generation unit includes a first catalyst layer having a predetermined thickness for the electrochemical reaction. A power generation region, and a second power generation region in which the anode-side catalyst layer has a thickness smaller than the predetermined thickness, and the predetermined substance in the fuel gas supply passage is oxidized through the second power generation region. Ga So as to be movable in the upstream portion of the supply passage, a fuel gas supply passage and the oxidizing gas supply passage is arranged with respect to the power generation unit.

  In the fuel cell according to the present invention, the electrochemical reaction between the oxidizing gas supplied from the oxidizing gas supply passage and the fuel gas supplied from the fuel gas supply passage to the power generation unit formed by the electrolyte member in the cell. Power is generated by being used in Here, the feature of the fuel cell according to the present invention is that, in this power generation unit, two power generation regions, the first power generation region, and the anode-side catalyst layer to which fuel gas is supplied from the fuel gas supply passage are different. The second power generation area is provided. The predetermined thickness of the anode side catalyst layer in the first power generation region is a thickness usually required for protonation of hydrogen necessary for an electrochemical reaction between oxygen and hydrogen in the power generation unit. On the other hand, the thickness of the anode side catalyst layer in the second power generation region is thinner than this predetermined thickness.

  Furthermore, the fuel cell according to the present invention is characterized by the relative arrangement of the oxidizing gas supply passage and the fuel gas supply passage through the second power generation region. That is, as described above, both passages are arranged so that the predetermined substance in the fuel gas supply passage can move to the upstream portion of the oxidizing gas supply passage. Here, the predetermined substance is a substance contained in the fuel gas supply passage, and the substance moves to the oxidizing gas supply passage, thereby contributing to humidification of the oxidizing gas flowing therethrough, for example, And water (water) and hydrogen in the fuel gas.

  In the second power generation region, the anode-side catalyst layer is thinner than the other regions (first power generation region) as described above. Therefore, the predetermined substance in the fuel gas permeates through the electrolyte member of the power generation unit and easily moves into the oxidizing gas in the upstream portion of the oxidizing gas supply passage having a high degree of drying. Therefore, when the predetermined substance is moisture, the oxidizing gas is directly humidified. In addition, when the predetermined substance is hydrogen, the thickness of the anode-side catalyst layer in the second power generation region is thinner than the predetermined thickness, so that the amount converted from hydrogen to protons is reduced, and the fuel gas supply passage and the oxidation are thereby reduced. A concentration gradient of hydrogen between the gas supply passage is generated. As a result, hydrogen moves to the oxidizing gas supply passage, and the moved hydrogen is oxidized and burned by the catalyst layer when the cathode side catalyst layer for electrochemical reaction is present on the cathode side of the power generation unit. Water is generated, thereby humidifying the oxidizing gas.

  As described above, the thickness of the anode catalyst layer in the fuel cell is distinguished between the first power generation region and the second power generation region, and the oxidizing gas supply passage and the fuel gas supply passage through the second power generation region. By devising the relative arrangement, the humidification of the oxidizing gas flowing through the upstream portion of the oxidizing gas that can be dried most efficiently and stably can be performed in the cell of the fuel cell. In the fuel cell according to the present invention, the presence of the cathode side catalyst layer in the second power generation region is not necessarily required. That is, when there is no cathode side catalyst layer, it is possible to humidify with moisture when the predetermined substance is moisture, and when the cathode side catalyst layer is present, humidification due to oxidative combustion of hydrogen in addition to moisture. Is executed.

  Here, in the fuel cell, the anode-side catalyst layer may not be provided in the second power generation region. That is, in the second power generation region, the anode side catalyst layer has a thickness of zero. This makes it easier for moisture in the fuel gas to move to the upstream portion of the oxidizing gas supply passage, and in the second power generation region, the hydrogen gas protonation causes the fuel gas supply passage and the oxidizing gas supply passage to be separated from each other. The mobility of hydrogen can be enhanced by prioritizing the sharpening of the hydrogen concentration gradient.

  Further, in a state where the anode side catalyst layer is not provided in the second power generation region, the cathode side catalyst layer for the electrochemical reaction may not be provided in the second power generation region. By doing in this way, the water | moisture content in fuel gas becomes easy to move to the upstream site | part of an oxidizing gas supply path.

  Here, in the fuel cell described above, the first power generation region and the second power generation region may have a common electrolyte portion made of a common electrolyte member in the power generation portion. That is, these two power generation regions are formed on the common electrolyte part. By doing in this way, it becomes possible to form the cell of the fuel cell concerning the present invention more compactly.

  The specific arrangement of the oxidizing gas supply passage and the fuel gas supply passage in the fuel cell described above will be exemplified below. For example, in the fuel cell described above, the oxidizing gas supply passage and the fuel gas supply passage are defined by a flow direction of the oxidizing gas flowing through the oxidizing gas supply passage and a flow direction of the fuel gas flowing through the fuel gas supply passage. The power generation part is sandwiched so as to be opposed to each other, and the upstream part of the oxidizing gas supply passage and the downstream part of the fuel gas supply passage are disposed to face each other with the power generation part interposed therebetween. Anyway. That is, the oxidizing gas supply passage and the fuel gas supply passage are arranged with the power generation unit sandwiched so as to be a so-called counter flow type. When arranged in this way, the downstream portion of the fuel gas supply passage faces the upstream portion of the oxidizing gas supply passage where drying is most a concern. The fuel gas flowing through the downstream portion of the fuel gas supply passage contains a relatively large amount of moisture that has permeated from the oxidizing gas supply passage. Therefore, the movement of moisture as described above is more effectively performed by arranging both passages in such a counterflow type.

  Here, when the fuel cell according to the present invention is viewed from another aspect, the following fuel cell is obtained. That is, the fuel cell according to the present invention is a fuel cell that generates electric power by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen in the cell, the oxidizing gas supplying the oxidizing gas into the cell. A supply passage, a fuel gas supply passage for supplying the fuel gas into the cell, an electrolyte member formed in the cell, an oxidizing gas supplied from the oxidizing gas supply passage, and the fuel gas supply passage. A power generation unit that generates power by an electrochemical reaction with the supplied fuel gas, and the power generation unit moves a predetermined substance in the fuel gas supply passage to the oxidizing gas supply passage compared to other regions. A predetermined power generation region that is easy to operate, and the fuel is supplied so that a predetermined substance in the fuel gas supply passage can move to an upstream portion of the oxidizing gas supply passage through the predetermined power generation region. Scan supply passage and the oxidizing gas supply passage is arranged to face the power generation unit.

  The predetermined substance here is synonymous with the predetermined substance described above. Therefore, in the above fuel cell, a predetermined power generation region is explicitly formed in the power generation unit in the cell, and movement of the predetermined substance from the fuel gas supply passage to the upstream portion of the oxidizing gas supply passage through the predetermined power generation region. It becomes possible. As a result, it is possible to efficiently and stably humidify the oxidizing gas flowing through the upstream portion of the oxidizing gas that can be dried most efficiently in the cell of the fuel cell.

Further, when the fuel cell according to the present invention is viewed from another aspect, the following fuel cell is obtained. That is, the fuel cell according to the present invention is a fuel cell that generates electric power by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen in the cell, the oxidizing gas supplying the oxidizing gas into the cell. A supply passage, a fuel gas supply passage for supplying the fuel gas into the cell, an electrolyte member, and an anode side catalyst layer and a cathode side catalyst layer provided between the electrolyte member in the cell are formed. And a power generation unit that generates power by an electrochemical reaction between the oxidizing gas supplied from the oxidizing gas supply passage and the fuel gas supplied from the fuel gas supply passage due to the catalytic effect of both catalyst layers, The unit has a predetermined power generation region in which the degree of power generation by the electrochemical reaction is lower than other regions, and the predetermined substance in the fuel gas supply passage through the predetermined power generation region So as to be movable in the upstream portion of the oxidizing gas supply passage, a fuel gas supply passage and the oxidizing gas supply passage is arranged with respect to the power generation unit.

  The predetermined substance here is synonymous with the predetermined substance described above. Here, the power generation by the electrochemical reaction by the power generation unit is due to the catalytic effect of the anode-side catalyst layer and the cathode-side catalyst layer provided with the electrolyte member interposed therebetween, and then the degree of power generation in the power generation unit A predetermined power generation region lower than the other regions is explicitly formed, and a fuel gas supply passage and an oxidant gas supply passage are arranged to face the power generation unit across the predetermined power generation region. In this predetermined power generation area, since the catalyst layer is less involved in power generation, a situation is formed in which the predetermined substance in the fuel gas supply passage easily moves to the oxidizing gas supply passage as described above. Will be. As a result, it is possible to move the predetermined substance from the fuel gas supply passage to the upstream portion of the oxidizing gas supply passage through the predetermined power generation region, and thus humidify the oxidizing gas flowing through the upstream portion of the oxidizing gas that can be dried most. Can be carried out efficiently and stably in the fuel cell.

  According to the fuel cell of the present invention, it is possible to efficiently and stably humidify the oxidizing gas in the fuel cell formed by the electrolyte member.

  Embodiments of a fuel cell according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a fuel cell 1 according to the present invention. The fuel cell 1 is formed in a state in which a plurality of cells 10 are stacked with both ends sandwiched between end plates 4 and 5. 1 is a configuration diagram when the fuel cell 1 is viewed from the upper side. In FIG. 1, a hydrogen supply pipe 21 and an air discharge pipe 22, which will be described later, are replaced with a hydrogen discharge pipe 23 and an air supply pipe 24. However, the hydrogen inlet manifold 2a and the air outlet manifold 3b are described in a state where the hydrogen outlet manifold 2b and the air inlet manifold 3a overlap each other. However, it can be understood from the following description and other drawings that these are independent components. In FIG. 1, the solid line arrow indicates the flow of hydrogen as the fuel gas, the broken line arrow indicates the flow of air as the oxidizing gas, and the fuel gas according to the present invention is simply referred to as hydrogen. The oxidizing gas is simply referred to as air.

  The fuel cell 1 generates power by an electrochemical reaction between oxygen and hydrogen in the air, and air and hydrogen are supplied from the outside of the fuel cell 1, respectively. Specifically, hydrogen is supplied to the fuel cell 1 through a hydrogen supply pipe 21 from a hydrogen storage tank provided outside the fuel cell 1. Air is supplied to the fuel cell 1 through the air supply pipe 23 as compressed air by a blower provided outside the fuel cell 1. The hydrogen sent through the hydrogen supply pipe 21 passes through the hydrogen inlet manifold 2a, and the air sent through the air supply pipe 24 passes through the air inlet manifold 3a to each stacked cell 10. Electric power is generated by being supplied to the electrochemical reaction in the cell 10.

Here, the configuration of the cell 10 will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing a schematic configuration of the cell 10, and FIG. 3 is a diagram showing the flow of the oxidizing gas (air) and the fuel gas (hydrogen) in the cell 10. The cell 10 is provided with an electrode assembly (hereinafter referred to as “MEA portion”) 11 that performs substantial power generation at the center thereof, and the hydrogen inlet manifold 2a, hydrogen outlet manifold 2b, and air inlet manifold described above are provided on both sides thereof. 3a and an air outlet manifold 3b are provided. The hydrogen inlet manifold 2a and the hydrogen outlet manifold 2b communicate with each other to form a hydrogen supply passage 11d described later, and the air inlet manifold 3a and the air outlet manifold 3b communicate with each other to form an air supply passage 11e described later. Yes.

  3 shows a schematic configuration of the MEA unit 11 when the MEA unit 11 is viewed from the upper side. The MEA portion 11 has a configuration in which a hydrogen supply passage 11d and an air supply passage 11e are provided on both sides of an MEA main body portion 11c formed of an electrolyte member, and this hydrogen is supplied through a hydrogen inlet manifold 2a. Hydrogen is sent to the supply passage 11d, and air is sent to the air supply passage 11e via the air inlet manifold 3a. Then, hydrogen and air sent from each supply passage are subjected to an electrochemical reaction in the MEA main body 11c to generate power. Thereafter, a part of the hydrogen and air that flows through the hydrogen supply passage 11d and the air supply passage 11e that has not been subjected to the electrochemical reaction, and moisture generated by the electrochemical reaction, are located in downstream portions of the respective passages. It flows to the hydrogen outlet manifold 2b and the air outlet manifold 3b.

  Here, in the middle stage and the lower stage of FIG. 3, the outline of the flow paths of the air supply passage 11e and the hydrogen supply passage 11d are respectively viewed from the side of the MEA main body 11c (that is, the viewpoint for the cell 10 shown in FIG. 2). The same). That is, in the cell 10 shown in FIG. 2, the hydrogen used for the electrochemical reaction flows from one upper surface of the MEA main body 11c to a plurality of branches on the way from the upper left to the lower right in FIG. It flows in a separate state. On the other hand, the air supplied to the electrochemical reaction flows on the other surface side of the MEA main body 11c from the upper right to the lower left in FIG. That is, in the cell 10, the form of the counter flow in which the flow of hydrogen and air is opposed is adopted. Therefore, in the cell 10, the upstream portion of the air flow is opposed to the downstream portion of the hydrogen flow, and the downstream portion of the air flow is opposed to the upstream portion of the hydrogen flow with the MEA main body 11c interposed therebetween. Thus, a hydrogen supply passage 11d and an air supply passage 11e are provided.

  In the cell 10 of the fuel cell 1 configured as described above, the MEA section 11 is distinguished into two regions, a first power generation region 11a and a second power generation region 11b. As shown in FIG. 2, the first power generation area 11a and the second power generation area 11b are configured such that a part on the right side of the MEA part 11 is a second power generation area 11b and a part on the left side of the MEA part 11 is a first part. One power generation region 11a is set. In other words, in the MEA portion 11, as clearly shown in FIG. 3, the downstream portion of the hydrogen supply passage 11d is opposed to the upstream portion of the air supply passage 11e with the MEA main body portion 11c interposed therebetween. A power generation region 11b is formed, and the other part is a first power generation region 11a.

  Here, the detailed structure of the MEA main body 11c in the first power generation region 11a and the second power generation region 11b will be described with reference to FIG. FIG. 4 is a diagram showing a detailed configuration of the MEA main body 11c. The MEA main body 11c includes an electrolyte member 12, an anode side catalyst layer 13 which is a catalyst layer on the side to which hydrogen is supplied (that is, the anode side), and a side to which air containing oxygen is supplied (that is, the cathode side). And the cathode side catalyst layer 14 which is a catalyst layer. The anode-side catalyst layer 13 converts hydrogen as a fuel gas into protons, and the cathode-side catalyst layer 14 promotes proton oxidation, thereby generating power by an electrochemical reaction in the fuel cell 1.

And in the 1st electric power generation area | region 11a, although the anode side catalyst layer 13a and the cathode side catalyst layer 14a are provided as a catalyst layer which has thickness required for the said electrochemical reaction, in the 2nd electric power generation area | region 11b, The cathode side catalyst layer 14b is provided in the same manner as the cathode side catalyst layer 14a, but the anode side catalyst layer 13b is not provided. That is, the thickness of the anode side catalyst layer 13b is zero. The MEA main body 11c configured as described above exhibits different functions in the first power generation region 11a and the second power generation region 11b, which will be described below with reference to FIG.

  FIG. 5 schematically shows the flow of a predetermined substance in the MEA unit 11 when the MEA unit 11 is viewed from above, as in the upper diagram of FIG. This predetermined substance is a substance in hydrogen that is a fuel gas that makes it possible to humidify air that is an oxidizing gas, and in this embodiment, water in hydrogen and its hydrogen correspond to this substance.

  First, the flow of moisture as the predetermined substance will be described. Protons that reach the cathode side through the MEA main body 11c by the electrochemical reaction in the cell 10 are oxidized by the cathode side catalyst, thereby generating water. Accordingly, the amount of moisture in the air flowing through the air supply passage 11e by the generated water increases as it proceeds to the downstream portion. This state is indicated by the thickness of the arrow in the air supply passage 11e in FIG. In other words, the downstream portion of the air supply passage 11e where the arrow is shown thicker contains more water in the air than the upstream portion.

  Then, due to the difference between the moisture content in the air supply passage 11e and the moisture content in the hydrogen supply passage 11d, the moisture in the air supply passage 11e permeates into the hydrogen supply passage 11d side through the MEA main body 11c. . In addition, this penetration | invasion of a water | moisture content is performed notably in the site | part which concerns on the 1st electric power generation area | region 11a from the midstream site | part to which a water | moisture content in the air supply path 11e becomes comparatively large from a downstream site | part. This is because the amount of water generated by the electrochemical reaction is small in the upstream portion of the air supply passage 11e, and a large amount of air flows at a high flow rate, so the amount of water contained in the air flowing through the upstream portion is extremely small. Because.

  Then, the moisture that has permeated the hydrogen supply passage 11c from the air supply passage 11e flows through the hydrogen supply passage 11d, and therefore increases as it proceeds to the downstream portion. This state is indicated by the thickness of the arrow in the hydrogen supply passage 11d in FIG. That is, the downstream portion of the hydrogen supply passage 11d where the arrow is thicker contains more moisture in the air than the upstream portion.

  Here, in the second power generation region 11b of the MEA portion 11, the downstream portion of the hydrogen supply passage 11d and the upstream portion of the air supply passage 11e are disposed to face each other with the MEA main body portion 11c interposed therebetween. And as shown in FIG. 4, in this 2nd electric power generation area | region 11b, the anode side catalyst layer 13b is not provided among the MEA main-body parts 11c. As a result, the moisture easily moves from the hydrogen flowing in the downstream portion of the hydrogen supply passage 11d containing a large amount of moisture as described above to the air flowing in the upstream portion of the air supply passage 11e having a very low water content. As a result, a cycle of moisture movement is formed in the cell 10, and it becomes possible to humidify the air in the upstream portion which is in the dryest state in the air flowing through the air supply passage 11e. Since the moisture cycle is performed in a state where it does not go outside the cell 10, the temperature drop of the moisture is suppressed as much as possible, and the liquefaction can be avoided. As described above, the entire air flowing through the air supply passage 11e can be humidified, and thus the MEA unit 11 can be efficiently and stably maintained in a humidity state suitable for an electrochemical reaction.

Next, the flow of hydrogen as the predetermined substance will be described. In the second power generation region 11b of the MEA unit 11, the anode side catalyst layer 13b is not provided as described above. Therefore, in this region, hydrogen flowing through the hydrogen supply passage 11d is not converted into protons. For this reason, the hydrogen concentration gradient between the hydrogen supply passage 11d and the air supply passage 11e, that is, the hydrogen concentration gradient between the hydrogen supply passage 11d having a high hydrogen concentration and the air supply passage 11e having a very low hydrogen concentration, Hydrogen easily moves from 11d to the air supply passage 11e. The transferred hydrogen is oxidized by the cathode side catalyst layer 14b in the second power generation region 11b, and water is generated there. Since this water is also generated in the cell 10, it can be avoided that the generated water is cooled and liquefied. As a result, it becomes possible to humidify the air in the upstream portion, which is in the dry state of the air flowing through the air supply passage 11e, so that the MEA unit 11 is efficiently put into a humidity state suitable for the electrochemical reaction. And it becomes possible to maintain stably.

  Moreover, although formation of the 2nd electric power generation area | region 11b in the said Example is as showing in FIG. 4, the other aspect of the 2nd electric power generation area | region 11b is demonstrated based on FIG. 6A and 6B. 6A and 6B are diagrams showing a detailed configuration of the MEA main body 11c, as in FIG. 6A, the anode side catalyst layer 13a on the first power generation region 11a side has the same thickness as that shown in FIG. 4, but the anode side catalyst layer on the second power generation region 11b side. About 13b, it is provided on the electrolyte member 12 in the state which has thickness thinner than the anode side catalyst layer 13a. The cathode side catalyst layer 14 is the same as the state shown in FIG.

  In the MEA main body portion 11c formed in this way, the anode side catalyst layer 13b is slightly left in the second power generation region 11b. Therefore, compared with the MEA main body portion 11c shown in FIG. Although the degree of movement of moisture and hydrogen to the upstream portion of the air supply passage 11e is slightly reduced, humidification of the air flowing through the upstream portion can be performed. On the other hand, since the anode-side catalyst layer 13b is slightly left in the second power generation region 11b, protons are generated to some extent on the anode side of the second power generation region 11b, so that the power generation efficiency is lower than that of the first power generation region 11a. However, it is possible to perform power generation also in the second power generation region 11b, and thus it is possible to improve the power generation amount in the entire fuel cell 1.

  Accordingly, if the MEA unit 11 can be maintained in a humidity state suitable for an electrochemical reaction even if a small amount of the anode side catalyst layer 13b is left in the second power generation region 11b, the MEA main body as shown in FIG. 6A. By adopting the structure of the portion 11c, the power generation amount of the fuel cell 1 can be improved.

  Next, in the MEA main body 11c shown in FIG. 6B, a state in which the cathode-side catalyst layer 14b on the second power generation region 11b side is further removed from the state shown in FIG. That is, no catalyst layer is provided on the electrolyte member 12 in the second power generation region 11b. By forming the MEA main body 11c in this way, moisture contained in hydrogen flowing through the hydrogen supply passage 11d can be easily moved by the air supply passage 11e. The hydrogen moved from the hydrogen supply passage 11d to the air supply passage 11e is not oxidized in the second power generation region 11b, but flows downstream in the air supply passage 11e and is oxidized by the cathode side catalyst layer 14a existing there. This contributes to the humidification of the air as the oxidizing gas.

  Here, the manufacturing method of the MEA main body 11c up to the above will be described with reference to FIG. First, in S101, a noble metal or the like that is a raw material of a catalyst that becomes a catalyst layer on each of the cathode side and the anode side is prepared in the form of a solution and stirred. Thereby, the noble metal in the catalyst is more uniformly diffused. Next, the prepared catalyst is applied onto a Teflon (registered trademark) sheet by the process of S102. At this time, the application amount to the Teflon (registered trademark) sheet is adjusted so that each catalyst layer has the thickness shown in FIG. 4, FIG. 6A, and FIG. 6B. Thereafter, the applied catalyst is dried by the process of S103 to create a “catalyst sheet”.

Thereafter, the catalyst sheet is cut according to the size of each power generation region as shown in FIGS. 4, 6A, and 6B. For example, when the MEA main body 11c shown in FIG. 4 is prepared, the catalyst sheet for the anode side catalyst layer 13 is made smaller than the catalyst sheet for the cathode side catalyst layer 14 by an area corresponding to the second power generation region 11b. Just cut. When the MEA main body portion 11c shown in FIG. 6A is prepared, catalyst sheets for two types of anode side catalyst layers having different thicknesses are prepared, and then each catalyst sheet is connected to the first power generation region 11a and the second power generation region 11a. Cutting is performed in accordance with the area of the power generation region 11b.

  Thereafter, in S105, the MEA main body portion 11c is created by transferring the catalyst layer formed on each catalyst sheet onto the electrolyte member 12 from the catalyst sheet cut in S104.

<Other examples>
In the embodiments described above, the arrangement of the hydrogen supply passage 11d and the air supply passage 11e in the MEA section 11 is such that the flow direction of hydrogen and air is a counter flow type as shown in FIG. Both passages are arranged. By being arranged in this way, the downstream portion of the hydrogen supply passage 11d and the upstream portion of the air supply passage 11e face each other. Here, other than this arrangement mode, an arrangement mode to which the present invention can be applied will be described with reference to FIGS.

  8 and 9 are diagrams showing the flow of the oxidizing gas (air) and the fuel gas (hydrogen) in the cell 10 as in FIG. In the MEA unit 11 shown in FIG. 8, the flow of hydrogen is the same as that shown in FIG. On the other hand, as shown in the middle part of FIG. 8, the air flow is from the upper side to the lower side in the drawing, that is, in the direction orthogonal to the hydrogen flow. In the arrangement form of the hydrogen supply passage and the air supply passage, the portion Rh1 surrounded by the dotted line in the middle and lower stages in FIG. 8, that is, the downstream portion of the hydrogen supply passage and the upstream portion of the air supply passage are the MEA main body portion. It is possible to humidify the air in the upstream part which is in the most dry state in the air flowing through the air supply passage by making the portion Rh1 opposed across the second power generation region in the above embodiments. It becomes.

  Next, in the MEA part 11 shown in FIG. 9, the flow of hydrogen and the flow of oxygen are formed on a single stroke. That is, the hydrogen supply passage 11d advances while meandering from the lower left to the upper right in the drawing as shown in the lower part of FIG. 9, and the air supply passage 11e is in the drawing as shown in the middle of FIG. Proceed while meandering from upper left to lower right. As a result, the hydrogen flow and the air flow are substantially in the same direction, unlike the counterflow type shown in FIG. In such an arrangement form of the hydrogen supply passage and the air supply passage, the portion Rh2 surrounded by a dotted line in the middle and lower stages in FIG. 9, that is, the downstream portion of the hydrogen supply passage and the upstream portion of the air supply passage are the MEA main body portion. It is possible to humidify the air in the upstream part which is in the most dry state among the air flowing through the air supply passage by setting the portion Rh2 opposed across the airflow as the second power generation region in the above embodiments. It becomes.

It is a figure which shows schematic structure of the fuel cell concerning this invention. FIG. 2 is a diagram showing a schematic configuration of cells included in the fuel cell shown in FIG. FIG. 3 is a first diagram showing the flow of oxidizing gas (air) and fuel gas (hydrogen) in the cell shown in FIG. 2. It is a 1st figure which shows the detailed structure of the MEA main-body part contained in the cell shown in FIG. It is a figure which shows typically the flow of the predetermined substance in this MEA part when the MEA part shown in FIG. 2 is seen from the upper side. FIG. 3 is a second diagram showing a detailed configuration of the MEA main body included in the cell shown in FIG. 2. FIG. 4 is a third diagram showing a detailed configuration of the MEA main body included in the cell shown in FIG. 2. It is a flowchart which shows the manufacturing process of the MEA main-body part contained in the cell shown in FIG. FIG. 3 is a second view showing the flow of oxidizing gas (air) and fuel gas (hydrogen) in the cell shown in FIG. 2. FIG. 3 is a third diagram showing the flow of oxidizing gas (air) and fuel gas (hydrogen) in the cell shown in FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2a ... Hydrogen inlet manifold 2b ... Hydrogen outlet manifold 3a ... Air inlet manifold 3b ... Air outlet manifold 10 ... Cell 11 ... MEA part 11a ... First power generation area 11b ... Second power generation area 11c ... MEA main body part 11d ... Hydrogen supply passage 11e ... Air supply passage 12 ... Electrolyte Member 13 ... Anode side catalyst layer 14 ... Cathode side catalyst layer

Claims (8)

A fuel cell that generates electricity by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen in a cell,
An oxidizing gas supply passage for supplying the oxidizing gas into the cell;
A fuel gas supply passage for supplying the fuel gas into the cell;
A power generation unit that is formed of an electrolyte member in the cell and that generates power by an electrochemical reaction between the oxidizing gas supplied from the oxidizing gas supply passage and the fuel gas supplied from the fuel gas supply passage. ,
The power generation unit includes a first power generation region in which the anode side catalyst layer for the electrochemical reaction has a predetermined thickness, and a second power generation region in which the anode side catalyst layer has a thickness smaller than the predetermined thickness. And having
The fuel gas supply passage and the oxidant gas supply passage are connected to the power generation unit so that the predetermined substance in the fuel gas supply passage can move to the upstream portion of the oxidant gas supply passage through the second power generation region. Placed against the part,
The fuel cell characterized by the above-mentioned.   2. The fuel cell according to claim 1, wherein the anode-side catalyst layer is not provided in the second power generation region.   The fuel cell according to claim 2, wherein a cathode side catalyst layer for the electrochemical reaction is not further provided in the second power generation region.   The fuel cell according to claim 1 or 2, wherein a cathode side catalyst layer for the electrochemical reaction is provided in the second power generation region.   The fuel cell according to any one of claims 1 to 4, wherein the first power generation region and the second power generation region have a common electrolyte part made of a common electrolyte member in the power generation part.   The oxidizing gas supply passage and the fuel gas supply passage are arranged such that the flow direction of the oxidation gas flowing through the oxidation gas supply passage and the flow direction of the fuel gas flowing through the fuel gas supply passage are opposed to each other. 2. The fuel cell according to claim 1, wherein the upstream portion of the oxidant gas supply passage and the downstream portion of the fuel gas supply passage are opposed to each other with the power generation unit interposed therebetween. Item 6. The fuel cell according to any one of Items 5. A fuel cell that generates electricity by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen in a cell,
An oxidizing gas supply passage for supplying the oxidizing gas into the cell;
A fuel gas supply passage for supplying the fuel gas into the cell;
A power generation unit that is formed of an electrolyte member in the cell and that generates power by an electrochemical reaction between the oxidizing gas supplied from the oxidizing gas supply passage and the fuel gas supplied from the fuel gas supply passage. ,
The power generation unit has a predetermined power generation region in which the predetermined substance in the fuel gas supply passage is more easily moved to the oxidizing gas supply passage than in other regions,
The fuel gas supply passage and the oxidizing gas supply passage are connected to the power generation unit so that the predetermined substance in the fuel gas supply passage can be moved to the upstream portion of the oxidizing gas supply passage through the predetermined power generation region. Arranged against
The fuel cell characterized by the above-mentioned. A fuel cell that generates electricity by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen in a cell,
An oxidizing gas supply passage for supplying the oxidizing gas into the cell;
A fuel gas supply passage for supplying the fuel gas into the cell;
An oxidizing gas formed in the cell by an electrolyte member and an anode-side catalyst layer and a cathode-side catalyst layer provided between the electrolyte members, and supplied from the oxidizing gas supply passage by the catalytic effect of both catalyst layers And a power generation unit that generates power by an electrochemical reaction between the fuel gas supplied from the fuel gas supply passage,
The power generation unit has a predetermined power generation region where the degree of power generation by the electrochemical reaction is low compared to other regions,
The fuel gas supply passage and the oxidizing gas supply passage are connected to the power generation unit so that the predetermined substance in the fuel gas supply passage can be moved to the upstream portion of the oxidizing gas supply passage through the predetermined power generation region. Arranged opposite to the
The fuel cell characterized by the above-mentioned.

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