JP2007184157A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of supplying oxidizer gas to a plurality of fuel battery cells uniformly. <P>SOLUTION: The fuel cell system is composed of a fuel cell stack part 18 formed by arranging a plurality of fuel battery cells 11 formed by interposing an electrolyte membrane between an anode and a cathode on a plane with the cathode laid upside; a body of equipment 14 covering cathode side face of the fuel cell stack part 18 so as to form an air flow space 29 between the cathode and itself, a fan 51 arranged so as to become flash with the fuel cell stack part 18, and a fan cover 52 covering every direction of the fan 51. The body of equipment is arranged so as to have an air inlet part 24 opened for introducing air to the air flow space, and an exhaustion part opened for exhausting the air. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell system, and more particularly to a planar stack type fuel cell system in which a plurality of fuel cells are arranged on the same plane.

  There is known a fuel cell system having an electrode-electrolyte membrane assembly (hereinafter referred to as MEA) in which an electrolyte membrane is sandwiched between an anode and a cathode. A type of fuel cell that supplies liquid fuel directly to the anode is called a direct fuel cell.

  The power generation mechanism is shown below. First, the supplied liquid fuel is decomposed on the catalyst supported on the anode to generate protons, electrons and intermediate products. The generated protons pass through the electrolyte membrane and move to the cathode side. On the other hand, the generated electrons move to the cathode side through an external load. Then, protons and electrons generate oxygen and reaction products in the air at the cathode. Power is generated by such a reaction.

For example, in a direct methanol fuel cell (hereinafter referred to as DMFC) that uses an aqueous methanol solution as a liquid fuel as it is, methanol and water react at the anode as represented by Formula 1 below, and As shown, protons and oxygen react to produce water.
(Scheme _{1); CH 3 OH + H} 2 O → CO 2 + 6H + + 6e,
(Scheme 2); 6H ⁺ + 6e ⁻ + 3 / 2O ₂ → 3H ₂ O

  As shown in Reaction Formula 2, in the reaction related to power generation, oxygen is consumed as an oxidizing agent at the cathode. In order to sufficiently secure the electromotive force of the fuel cell, it is necessary to sufficiently supply the oxidant to the cathode.

  On the other hand, research and development of a fuel cell system using liquid fuel has been actively promoted as a power source for various electronic devices including portable devices. The characteristics required for such a fuel cell system are: (1) electric power necessary for use as a power source can be secured, and (2) miniaturization and weight reduction that fits in the footprint of portable equipment. And so on.

  For example, in order to use as an electronic device power source such as a PC, since a single MEA has a small output, a plurality of fuel cells are connected and used. A high voltage and output can be obtained by connecting a plurality of fuel cells. When a plurality of fuel cells are connected, it is preferable that the power generation of each of the plurality of fuel cells is performed equally. Therefore, it is desired that the oxidant is supplied evenly to the plurality of fuel cells.

  As a method for supplying an oxidant to a fuel cell stack having a plurality of fuel cells, Patent Document 1 supplies air sucked by a centrifugal fan to a fuel cell via a manifold that expands in diameter downstream. In a fuel cell air supply device, a plurality of rectifying plates are provided in the manifold, and the rectifying plates are arranged so that the distance between them is increased toward the downstream of the manifold, and punching is performed downstream of the rectifying plate. An air supply device for a fuel cell configured to provide a rectifier made of at least one of a plate and a sponge is disclosed.

  Patent Document 2 proposes a method of supplying air to a plurality of fuel cells using a single fan. That is, Patent Document 2 discloses an electromotive portion formed by sandwiching an electrolyte plate between a fuel electrode and an oxidant electrode, an oxidant gas flow passage provided on the surface of the oxidant electrode and having both ends, and the oxidant gas flow passage. A fuel cell having a manifold communicated with one of the above and a decompression means for decompressing the inside of the manifold is disclosed. Moreover, it discloses that a current plate is formed in the manifold. Furthermore, it discloses that a prefilter is formed at the other end of the oxidant gas flow passage.

  Patent Document 3 discloses a centrifugal blower that supplies air to the fuel cell stack and an air flow path that is in contact with the air electrode of the fuel cell unit unit, and introduces air sent from the centrifugal blower. An air distribution means for distributing to the mouth, and a tubular body having a rectangular cross section, one end of the air inlet being an air outlet of the centrifugal blower and the other end of the air outlet being an air inlet of the air distributor An air supply device for a fuel cell including a connected air guide path is disclosed.

  By the way, as a method of arranging a plurality of fuel cells constituting the fuel cell stack, a bipolar type in which a plurality of fuel cells are stacked in a thickness direction and a planar stack type in which a plurality of fuel cells are arranged on the same plane Is known.

  In a bipolar fuel cell stack, a method is known in which a flow path is provided in a separator that divides adjacent fuel cells in order to supply an oxidant evenly to the cathode of each fuel cell.

  In relation to the above, Patent Document 4 discloses that a direct methanol fuel cell is installed in a fuel tank, and liquid fuel is supplied to the fuel electrode by convection through a flow path that vertically penetrates the separator surface. Discloses a fuel cell system for supplying air from a blower to an air flow path provided in a separator.

  Further, Patent Document 5 is a fuel cell comprising a plurality of unit cells stacked, and having a distribution flow path for distributing the fuel flowing in from the fuel inlet to each of the plurality of unit cells. There is disclosed a fuel cell including a fuel rectifying member that is disposed in a passage with a gap between an inlet and a porous body that transmits fuel and has a predetermined thickness.

  Patent Document 6 has a fuel gas channel on one side and an oxidant gas channel on the other side. The oxidant gas channel has a channel cross-sectional area at the inlet of the oxidant gas. A fuel cell separator is disclosed which is enlarged and has a reduced flow path resistance.

  In these techniques, in order to supply an oxidant gas sufficient for power generation of a high-power fuel cell to a small groove provided in the separator, it is compressed and sent by a high-power blower.

  In contrast to the bipolar type as described in the above document, the planar stack type is more suitable for devices such as notebook PCs that are intended to be carried. This is because there is a restriction on the thickness of devices that are intended to be carried. In the planar stack type, a plurality of fuel cells are arranged in a plurality of rows on a plane, and the fuel cells are connected in series by a current collector or the like. Moreover, when using for a portable apparatus, a fuel cell system is usually enclosed in a housing.

  Even in the planar stack type, it is necessary to supply the oxidant gas stably and uniformly to the cathode surfaces of the fuel cells in a plurality of rows.

  However, when the size of the airflow generation portion of the blower is smaller than the cathode surface of the plurality of rows of fuel cells, the airflow is biased on the cathode surface. That is, although the oxidant gas flows sufficiently in the fuel cell located in the air blowing or suction direction of the blower, the air current stays in the fuel cell located outside the air blowing direction or the suction direction, and the oxidant gas sufficiently. May not be supplied.

  In order to prevent such stagnation, a plurality of blowers and a large blower are arranged. In addition, a method is also known in which a complicated air flow path is formed using a blower having a high discharge force, a complex air flow path is formed, and an oxidant gas is supplied to each fuel cell.

  In portable devices, in order to reduce power consumption, it is desirable that the power consumption of a blower for blowing oxidant gas to the cathode is as small as possible. Moreover, when it is going to store a fuel cell system in a portable apparatus, the fuel cell system itself needs to be the magnitude | size below the footprint of a portable apparatus. That is, space saving is required. The above-described method of supplying the oxidant gas stably to the cathode surface in the planar stack type cannot be compatible with the demands required for such portable devices.

  In relation to the above, Patent Document 7 discloses that a plurality of single cells in which an air electrode and a fuel electrode are opposed to each other with an electrolyte layer interposed therebetween are arranged in a plane so that the same electrode is arranged on the same surface, and The single cells are connected in series by electrically connecting the back surface of the fuel electrode of the single cell and the back surface of the air electrode of the other single cell with a conductive Z-shaped connection plate, and the Z-shaped connection plate A flat fuel cell is disclosed in which through holes are provided in portions facing the fuel electrode and the air electrode, and fuel and air are supplied from the back of each electrode through the through holes of the Z-shaped connecting plate. .

  Patent Document 8 discloses a naturally aspirated fuel cell in which the cathode surface is opened to the atmosphere. That is, Patent Document 8 discloses a substantially flat casing having a part of an opening, and a substantially flat casing in which an electrolyte membrane is interposed between the fuel side electrode and the oxygen side electrode. There is disclosed a fuel cell comprising: a power generator; and air flow means disposed inside the casing of the opening to flow air around the air flow means.

Patent Document 9 proposes a fuel cell system in which an air chamber is provided on the cathode side and air is supplied by a blower.
JP-A-2005-42639 JP 2001-93562 A JP 2003-36878 A JP-A-2005-44585 JP-A-8-213044 JP 2004-192985 A JP 2002-56855 A JP 2003-86207 A JP 2005-129261 A

  However, in any of the above-described techniques, it is not yet possible to supply a uniform and sufficient oxidant gas to each fuel cell while satisfying the requirements required for portable equipment in the flat stack type. It was enough.

  An object of the present invention is to provide a fuel cell system capable of supplying an oxidant gas evenly to each of a plurality of fuel cells.

  Another object of the present invention is to provide a fuel cell system capable of supplying a sufficient amount of oxidant gas to all fuel cells.

  Still another object of the present invention is to provide a fuel capable of supplying an equal and sufficient amount of oxidant gas to each fuel cell after achieving space saving and power saving in a portable device. It is to provide a battery system.

  Hereinafter, means for solving the problem will be described using the numbers and symbols used in the best mode for carrying out the invention. These numbers and symbols are added with parentheses to clarify the correspondence between the description of the claims and the best mode for carrying out the invention. However, these numbers and symbols should not be used for interpreting the technical scope of the invention described in the claims.

  In the fuel cell system (1) according to the present invention, a plurality of fuel cells (11) having a structure in which an electrolyte membrane (33) is sandwiched between an anode (32) and a cathode (31) are arranged on the same plane. A fuel cell stack section (18), and a casing (14) that covers at least one surface of the fuel cell stack section (18) by providing an air flow space (29) between the cathode (31), and a fuel cell A single fan (51) arranged in the planar direction of the fuel cell stack (15) and a fan cover (52) covering all directions of the fan (51) are provided for the stack part (18). The housing (14) includes an intake opening (24) in which an air flow space (29) is opened to introduce gas, and an exhaust opening (25) that is opened to discharge gas. Arranged to have. The fan (51) is arranged so as to be parallel to the planar direction of the fuel cell stack part (18). The fan cover (52) has an intake port (53) provided on the fuel cell stack portion (18) side and an exhaust port (54) provided on the opposite side of the fuel cell stack portion (18) side. .

  According to the above configuration, the oxidant gas flows into the air flow space (29) by the air flow generated by the fan (50), and a sufficient amount of oxidant gas is supplied to the cathode (31). Since the fan (50) is surrounded by the fan cover (52), and only the intake port (53) and the exhaust port (54) are opened in a specific direction in the fan cover, the direction of intake and exhaust through the fan (50) Is limited. By doing so, the air flow to be supplied to the fuel cell stack can be made homogeneous. Exhaust gas from the fuel cell stack (15) can be efficiently guided to the fan (52).

  Moreover, since the fan (51) is arrange | positioned on the same plane as the plane of a fuel cell stack (15), the space of the thickness direction is suppressed. Therefore, space saving suitable for portable devices is achieved.

  The fuel cell system (1) according to the present invention further includes a partition (26) that divides the air flow space (29) into a plurality of regions on the plane of the fuel cell stack. The fan (50) generates an airflow that flows from the intake opening (24) to the exhaust opening (25) through the air flow space (29). The partition (26) is connected to the intake opening (24) so as to divide the open surface of the intake opening (24) at one end, and is exhausted so as to divide the open surface of the exhaust opening (25) at the other end. Connected to the opening (25).

  By providing the partition (26) as described above, the air flow space (29) is divided into a plurality of regions. The oxidant gas flowing from the intake opening (24) into the air flow space (29) is distributed to each of the plurality of regions. Since the oxidant gas is distributed to each of the plurality of regions, the oxidant gas does not stagnate on some of the fuel cells (11) and is distributed to all the cathodes (31) facing the air flow space (29). Supplied.

  The fuel cell system (1) according to the present invention further includes a pair of flow straightening plates (28) disposed so as to surround the space between the exhaust opening (25) and the air inlet (53) to form a flow straightening space (28). 30) and at least one guide plate (27) disposed in the rectifying space (28). The guide plate (27) is provided so as to divide the rectifying space (28) into a plurality of spaces. The guide plate (27) is connected to the intake port (53) so as to divide the opening surface of the intake port (53) at one end, and exhaust is released so as to divide the open surface of the exhaust opening portion (25) at the other end. Part (25).

  According to the above-described configuration, the oxidizing gas exhausted from the exhaust opening (25) is guided to the fan (50) by the rectifying plate (30). In addition to the suction force of the fan (50), the rectifying plate (30) guides the oxidant gas to the fan (50), so that an air flow can be efficiently generated in the air flow space (29). Moreover, since the inside of the rectification space (28) is divided into a plurality of spaces, the air exhausted from the exhaust opening (25) is distributed to any of the plurality of spaces. Since the oxidant gas distributed to any space is quickly sucked into the fan (50), the oxidant gas does not stagnate in a part of the rectifying space (28). Since the oxidant gas stays in the rectifying space (28), the airflow in the airflow space (29) is also restrained. Therefore, a sufficient and sufficient amount of oxidant gas is supplied to all fuel cells.

  In the fuel cell system (1) according to the present invention, the guide plate (27) is connected to the end of the partition (26) at one end.

  According to the above-described configuration, each space in which the rectifying space (28) is divided is associated with each area in which the airflow space (29) is divided. By providing the guide plate (27) so that one space corresponds to one region, the gas in the one region can be guided to the fan (50) through the one space. The oxidant gas in the one region is smoothly guided to the fan (50) without turbulent flow and stagnation when exhausted from the exhaust opening (25).

  In the fuel cell system (1) according to the present invention, the fuel cell stack (15) has a plurality of fuel cells (11) arranged in a lattice pattern. The fuel cell stack (15) is arranged such that the plurality of fuel cells (11) are rectangular as a whole.

  In the fuel cell system (1) according to the present invention, the width of the intake port (53) is smaller than the width of the exhaust opening portion (25).

  According to the present invention, since the oxidant gas is evenly distributed to each fuel cell (11) by the partition (26), the width of the fan (50) is made smaller than the width of the exhaust opening (25). be able to. Since the size of the fan (50) can be reduced, space can be saved.

  In the fuel cell system (1) according to the present invention, the fan cover (52) has an air intake surface facing the fuel cell stack portion (18). The fan cover (52) has an orthogonal surface that is orthogonal to the intake surface and also orthogonal to the fuel cell stack portion plane. The intake port (53) is provided in at least a part of the intake surface and at least a part of the orthogonal surface.

  In the fuel cell system (1) according to the present invention, the fan cover (51) is disposed so as to contact the stack exhaust opening (25).

  According to the above-described configuration, the fan (50) can suck the oxidant gas not only from the intake surface (58) but also from the surface (59) side orthogonal to the intake surface (58). Since the oxidant gas exhausted from the fuel cell stack (15) can be sucked from the orthogonal surface (59) side, the fan (50) can be disposed in contact with the fuel cell stack (15). . A stable air flow can be supplied to each air flow path, and the stack and the fan can be brought close to each other, and the fuel cell system itself can be further downsized. Since the space of the rectifying space (28) can be minimized, the space can be saved. As a result, it is possible to realize a fuel cell system capable of supplying air sufficient for power generation with a more compact structure even for a planar stack type fuel cell having an open portion larger than the fan aperture.

  In the fuel cell system (1) according to the present invention, the plurality of fuel cells (11) included in the fuel cell stack portion (18) are arranged so as to form a recess (62) in the planar direction. The fan (50) is disposed in the recess (62).

  As described above, space is saved by disposing the fan (50) in the recess (62).

  In the fuel cell system (1) according to the present invention, a plurality of fuel cells (11) having a structure in which an electrolyte membrane (33) is sandwiched between an anode (32) and a cathode (31) are arranged on the same plane. A fuel cell stack section (18), and a casing (14) that covers at least one surface of the fuel cell stack section (18) by providing an air flow space (29) between the cathode (31), and a fuel cell A single fan (51) arranged in the planar direction of the fuel cell stack (15) and a fan cover (52) covering all directions of the fan (51) are provided for the stack part (18). The housing (14) includes an intake opening (24) in which an air flow space (29) is opened to introduce gas, and an exhaust opening (25) that is opened to discharge gas. Arranged to have. The fan (51) is arranged so as to be parallel to the planar direction of the fuel cell stack part (18). The fan cover (52) has an exhaust port (54) provided on the fuel cell stack unit (18) side and an intake port (53) provided on the opposite side of the fuel cell stack unit (18) side. .

  According to the above configuration, the oxidant gas flows into the air flow space (29) by the air flow generated by the fan (50), and a sufficient amount of oxidant gas is supplied to the cathode (31). Since the fan (51) is arranged on the same plane as the plane of the fuel cell stack (15), the space in the thickness direction is suppressed. Therefore, space saving suitable for portable devices is achieved. Further, by providing the fan cover (52) with the intake port (53) and the exhaust port (54), the direction of intake and exhaust is limited. By providing the exhaust port (53) on the fuel cell stack (15) side, the oxidant gas can be efficiently supplied from the fan (52) to the fuel cell stack (15).

  In the fuel cell system (1) according to the present invention, the partition (26) is preferably formed of a water absorbent material having water absorbency.

  When a water-absorbing material is used as the partition (26), moisture condensed in the fuel cell stack (15) can be temporarily absorbed, so that power generation stoppage due to flooding can be prevented.

  In the fuel cell system (1) according to the present invention, the guide plate (27) is preferably formed of a water absorbent material having water absorbency.

  Since the guide plate (27) is made of a water-absorbing material, moisture condensed in the rectifying space (28) can be temporarily absorbed, and water leakage from the fuel cell system (1) is prevented.

  According to the present invention, a fuel cell system is provided in which an oxidant gas is evenly supplied to each of a plurality of fuel cells.

  Furthermore, according to the present invention, a fuel cell system capable of supplying a sufficient amount of oxidant gas to all fuel cells is provided.

  Furthermore, according to the present invention, a fuel capable of supplying an equal and sufficient amount of oxidant gas to each fuel cell after achieving space saving and power saving in a portable device. A battery system is provided.

  Furthermore, according to the present invention, in the planar stack type fuel cell system composed of a plurality of rows, the airflow supplied to the cathode can be supplied so as to obtain stable power generation. Moreover, since it is possible to use a device suitable for portable equipment such as a thin-type radial fan with low power consumption as the blowing means, the fuel cell system can be built in the portable equipment. Furthermore, since auxiliary devices such as fans can be built in the fuel cell stack, the fuel cell system itself can be miniaturized, leading to the widespread application of fuel cells to portable devices.

(First embodiment)
FIG. 5 is a top view of the fuel cell system 1 according to the present embodiment and a cross-sectional view of CC ′. The fuel cell system 1 includes a fuel cell stack portion 18, a pair of rectifying plates 17, a fan unit 16, a housing 14, a fuel container (not shown) for storing fuel, and a fuel flow. Pump (not shown), and wiring (not shown) for taking out electrical energy. In FIG. 5, the structure of the fuel cell stack 15 is actually covered with the casing 14 and cannot be seen, but is shown in a transparent manner for convenience of explanation. In the following description, a plane parallel to the fuel cell stack portion 18 is defined as an XY plane, and a direction perpendicular thereto is defined as a Z direction.

  When the fuel cell system 1 is mounted on a portable device, the fuel cell stack unit 18 is placed in the housing 14. The fuel cell stack unit 18, the rectifying plate 17, and the fan unit 16 are disposed on one surface inside the housing 14. One surface of the housing is present on the ± Z direction side of the fuel cell stack portion 18, the rectifying plate 17, and the fan unit. In FIG. 5, only the casing 14 existing on the + Z direction side of the fuel cell stack portion is shown.

  The fuel cell stack unit 18 has a plurality of fuel cell stacks 15. One fuel cell stack 15 is a group of a plurality of fuel cells 10 in a frame 10 unit to be described later. In the present embodiment, the fuel cell stack unit 18 has two fuel cell stacks 15. The two fuel cell stacks 15 are arranged on the same plane. One fuel cell stack 15 has a rectangular shape. The two fuel cell stacks 15 are adjacent to each other on one side, and the fuel cell stack unit 18 is also arranged in a rectangular shape. Each fuel cell stack 15 has a plurality of fuel cells 11. In the present embodiment, the fuel cells 11 are arranged in 3 rows × 3 columns to form one fuel cell stack 15. Further, in the present embodiment, all the fuel cells 11 are described as being arranged with the cathode 31 side facing upward (+ Z side). However, in the present invention, the cathodes 31 of all the fuel cells 11 are not limited to the upward direction, and it is sufficient that at least one cathode 31 is upward. In this case, the action and effect of the present invention described later are given to the upward cathode 31.

  The fan unit 16 is disposed on the Y direction side which is the planar direction side with respect to the fuel cell stack portion 18. The pair of rectifying plates 17 are arranged so that a space closed in the planar direction is formed by one side (side in the Y direction) of the fuel cell stack 18 and the fan unit 16. A casing 14 is disposed above and below (a Z direction side) the pair of rectifying plates 17. With such an arrangement, a space (rectification space 28) between the fan unit 16 and the fuel cell stack portion 18 is surrounded by the pair of rectifying plates 17, the fuel cell stack portion 18, the fan unit 16, and the housing 14. ) Is provided.

  The casing 14 is provided above and below the fuel cell stack 18 and the rectifying space 28 (± Z direction side). An air gap exists between the upper surface of the fuel cell stack 18 (the surface on the cathode 31 side) and the housing 14, and forms an air flow space 29. The casing 14 is in close contact with the fuel cell stack portion 18 at the end of the fuel cell stack portion 18 on the ± X direction side. On the other hand, there is a gap between the end of the fuel cell stack portion 18 on the ± Y direction side and the housing 14, the stack exhaust opening portion 25 on the Y direction side, and the stack intake opening on the −Y direction side. A portion 24 is formed. Thus, the airflow space 29 is a space where the ± X direction side is closed and the ± Y direction side is opened on the fuel cell stack portion 18. That is, the airflow space 29 communicates with the rectifying space 28 at the stack exhaust opening 25 and communicates with the outside through the stack intake opening 24.

  The rectifying space 28 communicates with the gas suction port of the fan unit 16. The fan unit 16 can inhale the gas in the rectifying space 28.

  The configuration of the fan unit 16 will be described in detail below. The fan unit 16 includes a fan cover 52 and a fan 51. The width of the fan unit 16 on the X direction side is narrower than the width of the stack exhaust opening portion 25.

  As the fan 51, a thin diameter flow fan is used. The fan 51 is arranged in parallel to the plane of the fuel cell stack 18 (XY plane in the figure), and is arranged so as to suck in airflow from the upper side (Z direction side in the figure). The fan 51 only needs to be able to blow air, and a sirocco fan, an axial fan, a cross flow fan, a turbo fan, or the like can also be used. However, in consideration of mounting in a portable device, it is preferable to use a low power consumption device such as a thin radial fan.

  The gas in the rectifying space 28 is sucked by the fan unit 16. Since the rectifying space 28 communicates with the airflow space 29, the gas in the airflow space 29 is also sucked. The fan unit 16 generates an airflow that flows from the stack intake opening 24 to the stack exhaust opening 25 in the airflow space 29.

  4A and 4B are diagrams showing the shape of the fan 51, where FIG. 4A is a top view, FIG. 4B is a side view, FIG. 4C is a perspective view seen from the exhaust direction side, and FIG. 4D is a view seen from the intake direction side. FIG. In the figure, the direction of the arrow indicates the direction of airflow.

  The fan 51 includes a rectangular parallelepiped fan casing 511 and a wing (not shown) provided inside the fan casing 511.

  The wing portion is fixed to the fan housing 511 via a support member (not shown). Airflow is generated by the rotation of the wings. The wings are arranged with the airflow suction side on the upper side (+ Z direction side).

The fan housing 511 is provided with a fan intake port 55 and a fan exhaust port 56.
The fan intake port 55 is a donut-shaped opening provided on the upper surface (surface on the Z direction side) of the fan housing 511. The fan exhaust port 56 is an opening provided on the side surface on the Y direction side.

  In the fan 51 having such a structure, the fan intake port 55 sucks air from a relatively large number of directions, and the fan exhaust port 56 forms a wide exhaust flow with a specific direction. Further, the airflow suction surface and the discharge surface are non-parallel, and the fan 51 is arranged in parallel to the fuel cell stack unit plane (XY plane), thereby occupying the space in the thickness direction (Z direction) of the fan 51. Can be suppressed. It is also possible to make it lower than the thickness of the fuel cell stack 15 having a planar stack type structure. Space saving in the thickness direction is more advantageous than using a fan in which the suction surface and the discharge surface are parallel, particularly when considering mounting in a portable device.

  The fan 51 that can be used in the present invention preferably has the shape and structure shown in FIG. 4, but is not limited thereto. As the fan 51, for example, air is sucked from one surface provided in the upper side (Z direction side in the drawing) and discharged from the opposite surface, or sucked from one surface through an exhaust path formed by an enclosure or the like For example, a structure that discharges in a non-parallel direction to the surface.

  It is desirable that the fan 51 used in the present invention, particularly the thin-diameter flow fan, be moisture-proofed or waterproofed so as to withstand the humid air that has passed through the cathode 31.

  The fan cover 52 is disposed so as to cover the fan housing 511. FIG. 6 is a diagram illustrating a state where the fan housing 511 is covered with the fan cover 52. (A) is a top view, (b) is a side view, (c) is a perspective view seen from the exhaust direction side, and (d) is a perspective view seen from the intake direction side. In the figure, the direction of the arrow indicates the direction of airflow. Further, the fan housing 511 is not actually seen, but is shown through.

  The shape of the fan cover 52 is a rectangular parallelepiped shape whose bottom surface is open. The fan cover 52 is provided with an intake port 53 and an exhaust port 54. The intake port 53 is an opening provided on the side surface in the −Y direction. On the other hand, the exhaust port 54 is an opening provided on the side surface in the Y direction.

  Although the air flow to be sucked is not limited to one direction only by the fan 51, the air flow can be limited to a certain direction by having the fan cover 52 provided with the air inlet 53 and the air outlet 54. In this case, intake is performed from the −Y direction side and exhaust is performed to the + Y direction side. Therefore, the airflow flowing on the upper surface of the cathode 31 can be given directionality toward the + Y direction.

  Suitable materials for the fan cover 52 include metals such as stainless steel and plastics such as acrylic. In particular, when metal is used, it is predicted that the moist air sent to the fan 51 will be condensed, so it is desirable to coat the surface with a protective film such as paint or a plastic sheet. However, the material of the fan cover 52 is not limited to this.

  With the above-described configuration, when the fan 51 takes in air from the upper surface side, an airflow flowing from the outside to the fan 51 through the air flow space 29, the rectifying space 28, and the air inlet 53 is generated. A part of the airflow supplied to the airflow space 29 is supplied to the cathode 31 as an oxidant gas. On the other hand, the airflow sucked by the fan 51 is discharged to the outside from the fan exhaust port 56 provided on the Y direction side. Here, since the air inlet 53 provided in the fan cover 52 is provided on the −Y direction side, the direction of the airflow is limited to the + Y direction side. Since the direction of the airflow is limited, the exhaust from the fuel cell stack unit 18 is efficiently guided to the fan unit 16.

  Next, the configuration of the fuel cell stack unit 18 will be described in detail. The fuel cell stack unit 18 has two fuel cell stacks 15. The two fuel cell stacks 15 are electrically connected in parallel or in series. The required voltage and output can be generated by using a plurality of fuel cell stacks 15 instead of a single one. A plurality of fuel cell stacks 15 are required in this way when it is intended to be used for a portable device such as a PC that requires relatively large power.

  FIG. 1 is a top view showing the configuration of the fuel cell stack 15. The fuel cell stack 15 is formed by arranging nine fuel cells 11 on a frame 10 in 3 rows × 3 columns. All the fuel cells 11 are arranged with the cathode 31 side facing upward (the + Z direction side in the figure).

  The frame 10 is provided with a plurality of fuel tank portions 12, a fuel path 23, a stack fuel inlet 21, and a stack fuel outlet 22. In FIG. 1, the structure provided on the frame 10 such as the fuel path 23 is not actually seen, but is shown through for convenience of explanation.

  Each of the plurality of fuel tank portions 12 is provided corresponding to each position of the plurality of fuel cells 11. The fuel supplied to the corresponding fuel battery cell 11 is stored in the fuel tank 12. The fuel path 23 is provided so as to connect the fuel tank portions 12 to each other. One fuel tank portion 12 is provided with a stack fuel inlet 21. Stack fuel outlets 21 are provided in the other two fuel tank portions 12.

  The fuel tank portion 12 is provided with an inlet for taking in fuel and an outlet for discharging. These inlets and outlets are connected by a fuel path 23 so as to connect to the outlets or inlets of adjacent cells. Thus, the fuel flow path of the fuel cell stack 15 including the fuel tank portion 12 is formed by connecting the fuel tank portions 12 adjacent in the fuel path 23.

  In FIG. 1, the arrow indicates the direction in which the fuel flows. The fuel is supplied to one fuel tank section 12 via the stack fuel inlet 21. The fuel is sequentially supplied from one fuel tank unit 12 to another adjacent fuel tank unit 12 via the fuel path 23. The fuel returns from the fuel tank portion 12 corresponding to the most downstream to the fuel container via the stack fuel outlet 22. In this way, a fuel circulation system is formed. FIG. 1 shows a state in which fuel is supplied to the fuel tank portions 12 in the central row of the three rows of fuel cells 11 and then distributed to the left and right rows.

  FIG. 2 is a view showing an AA ′ cross section of FIG. 1. A fuel holding material called a wicking material 60 is inserted into the fuel tank portion 12. The wicking material 60 is intended to absorb and hold an aqueous methanol solution (liquid fuel) mainly by capillary action. As the wicking material 60, for example, a woven fabric, a nonwoven fabric, a fiber mat, a fiber web, a foamed plastic, or the like can be used, and in particular, a hydrophilic material such as a hydrophilic urethane foam material or a hydrophilic glass fiber is used. preferable. The liquid fuel supplied to the fuel tank unit 12 is partly absorbed by the wicking material 60, but most of the liquid fuel is supplied to the anode 32 of the MEA 13, and power is generated by a cell reaction. The fuel that is supplied to the fuel tank unit 12 but not used for power generation returns to the fuel container again or is temporarily absorbed by the wicking material 60. However, the wicking material 60 is not necessarily an essential component and may be omitted when the fuel cell 11 located at a position corresponding to the downstream portion of the fuel path can supply fuel at a fuel concentration that enables sufficient power generation. There is also a case.

  As the fuel, fluid fuel can be used. The fuel is generally methanol. However, not limited to methanol, liquid fuels such as alcohols such as ethanol and isopropanol, ethers, and polyethers, and gaseous fuels such as hydrogen can also be used. In addition, as a method of supplying fuel, such a fuel supply system is an example, and the method of the present invention is not limited to this fuel supply system.

  The fuel battery cell 11 is disposed on the fuel tank portion 12. The fuel cell 11 includes an electrolyte membrane 33, a cathode 31 disposed on and in contact with one surface of the electrolyte membrane 33, an anode 32 disposed on and in contact with the other surface, a cathode The cathode current collector 41 and the anode current collector 42 disposed in contact with the anode 31 and the anode 32, respectively, and the seal member disposed on the periphery of the electrolyte membrane 33 and sandwiched between the electrolyte membrane 33 and the anode current collector 42 43. That is, the electrolyte membrane 33, the cathode 31, and the anode 32 constitute the MEA 13. On the upper and lower surfaces of the MEA 13, a cathode current collector 41 and an anode current collector 42 are configured with a seal member 43 interposed therebetween.

  The seal member 43 sandwiched between the electrolyte membrane 33 and the anode current collector 42 is arranged in a frame shape on the periphery of the current collector. The fuel battery cell 11 of the present invention has a cell structure having such a configuration, and is fixed to the frame 10 with a plurality of screws so as to penetrate the periphery of the cell structure. The means for fixing the fuel cell 11 to the frame 10 is not limited to screwing, and a method such as adhesion may be used as long as the liquid fuel does not leak from the fuel cell 11. Further, the configurations of the MEA 13 and the seal member 43 are not limited to those described in the present embodiment, and may be any structure as long as fuel does not leak.

  Examples of the fuel cell 11 of the present invention include a direct methanol fuel cell that uses an aqueous methanol solution as a liquid fuel as it is. In the case of the structure as shown in FIG. 2, power generation occurs when the liquid fuel stored in the fuel tank unit 12 is supplied to the anode 32. However, a gas-liquid separation membrane such as PTFE may be disposed between the fuel tank unit 12 and the anode 32. In this case, only the gaseous component of the fuel passes through the gas-liquid separation membrane and is supplied to the anode 32.

  The MEA 13 has a structure in which an electrolyte membrane 33 is sandwiched between a cathode 31 and an anode 32. As the electrolyte membrane 33, a polymer membrane having high proton conductivity and no electron conductivity is preferably used. The constituent material of the solid polymer electrolyte membrane 33 is preferably an ion exchange resin having a strong acid group such as a sulfonic acid group, a phosphoric acid group, a phosphone group, and a phosphine group, and a polar group such as a weak acid group such as a carboxyl group. Specific examples include perfluorosulfonic acid resins, sulfonated polyether sulfonic acid resins, sulfonated polyimide resins, and the like. More specifically, for example, sulfonated poly (4-phenoxybenzoyl-1,4-phenylene), sulfonated polyetheretherketone, sulfonated polyethersulfone, sulfonated polysulfone, sulfonated polyimide, alkylsulfonated polybenzo Examples thereof include a solid polymer electrolyte membrane made of an aromatic polymer such as imidazole. The film thickness can be appropriately selected within a range of about 10 to 300 μm depending on the material, the use of the fuel cell, and the like.

  The cathode 31 is an electrode that reduces oxygen to water as shown in the above formula 2, for example, particles (including powder) in which a catalyst is supported on a carrier such as carbon or a catalyst alone having no carrier And a catalyst layer with a proton conductor can be obtained by coating or the like on a substrate such as carbon paper. Examples of the catalyst include platinum, rhodium, palladium, iridium, osmium, ruthenium, rhenium, gold, silver, nickel, cobalt, molybdenum, lanthanum, strontium, yttrium, and the like. The catalyst may be used alone or in combination of two or more. Examples of the particles supporting the catalyst include carbon-based materials such as acetylene black, ketjen black, carbon nanotubes, and carbon nanohorns. For example, when the carbonaceous material is a granular material, the size of the particles is appropriately selected within a range of about 0.01 to 0.1 μm, preferably within a range of about 0.02 to 0.06 μm. In order to support the catalyst on the particles, for example, an impregnation method can be applied.

As the base material on which the catalyst layer is formed, a solid polymer electrolyte membrane can be used, and carbon paper, a carbon molded body, a carbon sintered body, a sintered metal, a foamed metal, etc. having a conductive porous property. Sexual substances can also be used. When a base material such as carbon paper is used, after forming the catalyst layer on the base material to obtain the cathode 31, the catalyst layer is in contact with the solid polymer electrolyte membrane 33 by a method such as hot pressing. It is preferable to join the cathode 31 to the solid polymer electrolyte membrane 33. The catalyst amount per unit area of the cathode 31, depending on the catalyst type and size, ^etc., and can be appropriately selected within 0.1mg / cm ² ~20mg / cm 2 in the range of about.

The anode 32 is an electrode that generates hydrogen ions, CO _2, and electrons from a methanol aqueous solution and water, as shown in the above formula 1, and is configured in the same manner as the cathode 31 described above. The catalyst layer and base material constituting the anode 32 may be the same as or different from the catalyst layer and base material constituting the cathode 31. The catalyst amount per unit area of the anode 32, as in the case of the cathode, depending on the catalyst type and size, ^etc., and can be appropriately selected within 0.1mg / cm ² ~20mg / cm 2 in the range of about.

  The cathode current collector 41 and the anode current collector 42 are disposed on and in contact with the cathode 31 and the anode 32, respectively, and act to increase the electron extraction efficiency and the electron supply efficiency. As shown in FIG. 2, these current collectors 41 and 42 may have a frame shape in contact with the peripheral edge of the MEA, or may have a flat plate shape or mesh shape in contact with the entire surface of the MEA. Also good. In the case of a flat plate shape, through holes through which fuel and air can enter are provided regularly or irregularly, and contact is made with the electrodes at portions where the through holes are not formed, thereby collecting current. Examples of the material of these current collectors 41 and 42 include stainless steel, sintered metal, foam metal, etc., or a conductive material such as a material obtained by plating these metals with a highly conductive metal material, or a carbon material. Can be used. In FIG. 2, the cathode current collector 41 is drawn so as to cover the upper side of the cathode 31, but actually has a frame shape. Therefore, the upper surface of the cathode 41 is open at the center.

  A plurality of seal members 43 are provided in one fuel cell 11. The seal member 43 has a sealing function. For example, as shown in FIG. 2, (1) a seal member 43 having a thickness substantially the same as the thickness of the cathode 31 is formed between the electrolyte membrane 33 and the cathode current collector 41 in a frame shape around the periphery of the cell structure. Is provided. (2) Between the electrolyte membrane 33 and the anode current collector 42, a seal member 43 having a thickness substantially the same as the thickness of the anode 32 is provided in a frame shape on the periphery of the cell structure. (3) A seal member 43 having an arbitrary thickness is provided between the anode current collector 42 and the frame 10. Each of these sealing members preferably has sealing properties, insulating properties, and elasticity, and is usually formed of rubber or plastic having a sealing function. Specifically, it is preferable to use plastic materials such as PTFE, PET, PEEK, and vinyl chloride, and rubber materials such as fluororesin, silicon rubber, and butyl rubber. However, the shape, configuration, position, and the like of the seal member 43 are not as described here, and may have at least a seal function.

  Next, the flow of gas supplied to the cathode 31 will be described. FIG. 3 is a diagram illustrating the flow of airflow when the fan cover 52 is not used. In the figure, arrows indicate the direction of airflow. The configuration is the same as that of the fuel cell system 1 according to this embodiment except that the fan 51 is not covered with the fan cover 52. When the upper part of the fan inlet 55 of the fan 51 is opened without using the fan cover 52, gas is sucked into the fan 51 from almost all directions in the XY plane direction.

  On the other hand, according to the present embodiment shown in FIG. 5, the flow of the airflow can be limited by using the fan cover 52 having the intake port 53 and the exhaust port 53. By providing the intake port 53 on the -Y direction side, intake can be selectively performed from the fuel cell stack unit 18 side (rectifying space 28). Thereby, the airflow in the airflow space 29 on the surface of the cathode 31 is also limited to the + Y direction side. Since the airflow can be unidirectional on the surface of the cathode 31, partial stagnation does not occur. Therefore, it is not necessary to use a plurality of fans or a large fan. Even if a fan having a smaller size than the size of the fuel cell stack portion 18 is used, the oxidant gas can be evenly supplied to every corner of the fuel cell stack portion 18.

  Further, by limiting the direction of the airflow, the fan 51 can be efficiently sucked, so that the fan unit 16 that is small and consumes less power can be selected.

  Fuel cells tend to be unable to generate sufficient power at low temperatures. By reducing the size of the fan and generating a uniform air flow in the fuel cell stack unit 18, overcooling of the fuel cells can be prevented. Moreover, although the drying of the cathode may occur due to excessive air blowing by the fan, this can be similarly prevented.

  Furthermore, by arranging the fan in the planar direction of the fuel cell stack portion 18 so as to be parallel to the planar direction, the space occupied in the thickness direction is suppressed. Therefore, the fuel cell system can be reduced in thickness.

(Second Embodiment)
A second embodiment will be described. FIG. 7 is a top view of the fuel cell system 1 according to the present embodiment and a cross-sectional view of the DD ′ plane. In the fuel cell system 1 according to the present embodiment, a partition 26 is added to the first embodiment. Since the configuration other than the partition 26 is the same as that of the first embodiment, the description thereof is omitted.

  The partition 26 is provided so as to divide the airflow space 29 into a plurality of regions. In the present embodiment, six rows of fuel cells 11 are arranged, but the partitions 26 are provided between adjacent rows. The partition 26 is provided in close contact with the casing 14 and the fuel cell stack 15 in the thickness direction. The air flow introduced from the outside into the air flow space 29 through the stack intake opening 24 is separated into each row of the fuel cells 11 by the partition 26.

  Here, the partition 26 is not necessarily provided between adjacent rows of the fuel cells 11. It is also possible to provide a single fuel cell 11 so as to divide the cathode surface 31. In this case, even if a situation occurs in which a sufficient amount of oxidant gas is not supplied in a certain airflow space 29, the situation is such that power generation is locally stopped because the airflow space 29 is supplied from another adjacent airflow space 29. Can be prevented.

  As a material of the partition 26, a plastic material having no conductivity is preferable. In particular, in order to maintain airtightness, it is preferable to use an elastic material such as urethane or rubber. In addition, when a water-absorbing material is used, moisture condensed in the inside of the housing 14 can be temporarily absorbed, thereby preventing power generation from being stopped due to flooding. The material of the partition 26 can be a combination of two or more different materials.

  About one or two partitions 26 may be used between the rows formed by the fuel cells 11. When two or more partitions are used, a space is formed between the partitions 26, and by providing a portion through the partition 26, it is possible to discharge excess moisture in the airflow space 29. In that case, it can be functionalized by using a porous body such as PTFE or PVA or other fibrous material as the material of the partition 26.

  In the fuel cell stack portion 18, the oxidant gas is difficult to be supplied to both corner portions on the stack exhaust opening portion 25 side (+ Y direction side) and at a portion away from the fan 51 (± X direction side). According to the present embodiment, by providing the partition 26, it is possible to supply sufficient oxidant gas to the cathodes 31 at both corners. Compared to the first embodiment, the oxidant gas is more evenly supplied to the surface of the cathode 31 of the fuel cell stack unit 18.

(Third embodiment)
A third embodiment will be described. FIG. 8 is a top view of the fuel cell system 1 according to the present embodiment and a cross-sectional view at EE ′. In the fuel cell system 1 according to the present embodiment, a guide plate 27 is added to the second embodiment. Since the configuration other than the guide plate 27 is the same as that of the second embodiment, description thereof is omitted.

  As in the second embodiment, in order to form a sufficient airflow only by the partition 26, the fan 51 and the stack 15 in the rectifying space are sufficiently separated from each other, and the fuel cells 11 located on both sides are separated. However, it is necessary to form a sufficient air flow. Therefore, a guide plate 27 is added in the present embodiment.

  Four guide plates 27 are provided in the rectifying space 28. Each guide plate 27 is connected to the intake port 53 at one end and to the stack exhaust opening 25 at the other end. At the connecting portion between the guide plate 27 and the intake port 53, the end portion of the guide plate 27 is arranged in the opening surface of the intake port 53. Thus, the opening surface of the intake port 53 is divided into five by the end portions of the four guide plates 27. The two guide plates are connected to the end portion of the partition 26 provided between the outermost row on the ± X direction side and the second row from the outside at the connecting portion with the stack exhaust opening portion 25. Yes. Further, the other two guide plates 27 are partitions 26 provided between the second row from the outside on the ± X direction side and the third row from the outside at the connecting portion with the stack exhaust opening portion 25. It is connected to the end.

  The rectifying space 28 has a plurality of spaces partitioned by the guide plate 27. Outer space 28 </ b> A among the plurality of spaces communicates with outer region 29 </ b> A among the plurality of regions into which airflow space 29 is divided. Similarly, the second space 28B from the outside communicates with the second region 29B from the outside, and the central space 28C communicates with the two regions 29C located at the center.

  The upper and lower sides (± Z direction side) of the guide plate 27 are in close contact with the housing 14. However, in order to produce the rectifying effect, it is not always necessary to seal, and it is sufficient that it is almost sealed.

  Thus, by dividing the rectifying space 28 into a plurality of spaces by the guide plate 27, the gas exhausted from the stack exhaust opening 25 is introduced into any of the plurality of spaces. In each space, a one-way air flow is generated from the stack exhaust opening 25 to the fan air inlet 53, and the stay in the rectifying space 28 is suppressed.

  Further, the guide plate 27 is preferably one having high thermal conductivity. By using the one having high thermal conductivity, the heat of the gas exhausted from the fuel cell stack portion 18 can be dispersed. Therefore, livestock heat to the fuel cell stack unit 18 is prevented.

  High-temperature and high-humidity exhaust gas that has passed through the cathode surface of the fuel cell stack portion 18 flows into the rectifying space. If the fan 51 sucks the exhaust as it is, condensation may occur inside the fan, or moisture exhausted from the fan may condense inside the device.

  Further, it is preferable to use a water-absorbing material as the guide plate 27. Moisture condensed in the rectifying space 28 can be temporarily absorbed. Moreover, it also leads to prevention of water leakage from the fuel cell system 1.

  As the material of the guide plate 27, a metal itself or a material whose surface is covered with a vinyl sheet or the like can be used, and a non-conductive plastic material or the like can also be used. Examples of such materials include metals having high thermal conductivity such as Cu, Al, Au, and Ag, light metals such as Mg and Ti, and metal materials having high corrosion resistance such as SUS. However, since the metal is easily corroded if it is exposed as it is, it is desirable to coat the metal surface with a plastic material such as PP (polypropylene) or vinyl.

  Moreover, when providing water absorption to the guide board 27, fiber materials, such as a foaming urethane material, a PVA-type material, cloth, and paper, are mentioned.

  The material of the guide plate 27 can be a combination of two or more different materials, and the guide plate itself may be formed of two or more members. As described above, when combining metal materials and water-absorbing materials, it is possible to bond them with double-sided tape or heat-conductive glue (such as high-heat-conducting silicone grease), or cut the water-absorbing materials into metal materials. The method of inserting | pinching is mentioned.

  According to the present embodiment, the intake force of the fan 51 is distributed to each space into which the rectifying space 28 is divided. Therefore, gas is evenly sucked even in a region located outside of the airflow space. That is, the oxidant gas is supplied to the fuel cells 11 more evenly.

  In the second embodiment, in order to generate an airflow in the Y direction side in the airflow space 29, it is necessary to arrange the airflow with a certain distance between the fan 51 and the fuel cell stack 15. On the other hand, according to the present embodiment, the air flow space 29 is connected regardless of the distance between the fuel cell stack unit 18 and the fan 51 by connecting the air inlet 53 and each row of the fuel cells 11 in an airflow manner. The internal airflow can be limited to the + Y direction. Therefore, the distance between the fan unit 16 and the fuel cell stack 15 can be reduced. That is, the area occupied by the rectifying space 28 can be reduced.

  Further, the amount of air taken from each row of fuel cells can be optimized by adjusting the connection position between the air inlet 53 and the end of the guide plate 27. By doing so, the same amount of oxidant gas as the fuel cells in the central row is supplied to the fuel cells in the rows at the both ends where the air flow is not easily generated when the partition 26 is not provided. can do.

(Fourth embodiment)
A fourth embodiment will be described. FIG. 9 is a top view of the fuel cell system 1 according to the present embodiment and a cross-sectional view of the DD ′ plane. In the figure, arrows indicate the direction of airflow.
In the fuel cell system 1 according to the present embodiment, the position of the intake port 53 is changed with respect to the third embodiment. Further, the layout of the fan unit 16 is changed. Further, the connection position between the guide plate 27 and the intake port 53 is changed. Other configurations are the same as those of the third embodiment, and a description thereof will be omitted.

  FIG. 10 is a diagram illustrating a state where the fan housing 511 is covered with the fan cover 52. (A) is a top view, (B) is a side view, (C) is a perspective view seen from the exhaust direction side, and (D) is a perspective view seen from the intake direction side. In the figure, the direction of the arrow indicates the direction of airflow. Further, the fan housing 511 is not actually seen, but is shown through.

  The intake port 53 is an opening provided on the end portion of the side surface of the fan cover 52 on the −Y direction side and on the −Y direction side of the side surface of the ± X direction. That is, the corner corresponding to the ± X direction side on the −Y direction side is cut out. The central part of the surface on the −Y direction side is closed by a shielding plate 57.

  Please refer to FIG. The fan unit 16 is disposed so as to contact the exhaust opening 25 of the fuel cell stack 18. The guide plate 27 is connected at one end to the air inlet 53 on the side surface of the fan cover 52 on the ± X direction side. The guide plate 27 is connected to the partition 26 at multiple ends.

  Since the central part of the fan inlet 53 parallel to the exhaust outlet 54 is closed by a shielding plate 57, the amount of airflow exhausted from the central row 29C among the plurality of fuel cells 11 is limited. Is done. When the shielding plate 57 is not provided, the airflow from the central row 29C tends to increase from the central row 29C as compared to the row 29A at both ends. By restricting, the amount of airflow in each row can be equalized.

  According to the present embodiment, in addition to the operation in the third embodiment, the distance between the fan 51 and the fuel cell stack 15 is substantially increased by providing the intake port 53 and the exhaust port 54 in a non-parallel portion. It can be eliminated. Therefore, the space is further saved.

(Fifth embodiment)
A fifth embodiment will be described. FIG. 11 is a top view of the fuel cell system 1 according to the present embodiment and a cross-sectional view of the FF ′ plane. In the figure, arrows indicate the direction of airflow. The description of the same configuration as that of the first embodiment is omitted.

  The fuel cell stack portion 18 is disposed so as to have a concave portion that is concave on the −Y direction side. That is, one fuel cell stack 15 in which a plurality of fuel cells 11 are arranged in an L shape and another fuel cell stack 15 in an inverted L shape face each other to form a recess.

  As in the first embodiment, the casing 14 is arranged with an airflow space 29 on the fuel cell stack portion 18.

  The air flow space 29 is opened at the outer end portion on the ± X direction side and the end portion on the −Y direction side of the fuel cell stack portion 18 to form a stack intake port 24. Further, the end facing the recess is also opened to form a stack exhaust port 25. On the other hand, it is closed at the end in the Y direction side outside the recess.

  A plurality of partitions 26 are provided. Each of the two partitions 26 is provided so that one end is connected to the inner corner of the recess and the other end is connected to the −Y direction side end of the fuel cell stack 18. Further, the other two partitions 26 are provided so as to divide a portion where the fuel cell stacks 15 face each other.

  The fan unit 16 is disposed so as to be built in the recess. FIG. 12 is a diagram illustrating the shape of the fan unit. (A) is a top view, (B) is a side view, (C) is a perspective view seen from the exhaust direction side, and (D) is a perspective view seen from the intake direction side. In the figure, the direction of the arrow indicates the direction of airflow. Further, the fan housing 511 is not actually seen, but is shown through.

  In the fan unit 16, the position of the air inlet 53 provided in the fan cover 52 is devised. The side surface on the ± X direction side of the fan cover 52 is open and serves as an intake port 531. In addition, both ends of the side surface of the fan cover 52 on the −Y direction side are also opened, and serve as intake ports 531.

  Refer to FIG. 11 again. Each of the pair of rectifying plates 17 is connected to the Y direction side corner of the recess of the fuel cell stack 18 at one end, and connected to the Y direction side corner of the fan cover 52 at the other end.

  Four guide plates 27 are provided. Each of the two guide plates 27 is connected to the −Y direction side corner of the fan cover 52 at one end, and is connected to the recess −Y direction side corner of the fuel cell stack 18 at the other end. Each of the other two guide plates 27 is connected to the central portion of the side surface on the −Y direction side of the fan cover 52 at one end, and provided at the portion where the two fuel cell stacks 15 face at the other end. The ends of the two partitions 26 are connected to each other. In this way, each guide plate 27 is connected to the partition 26 at one end.

  According to the present embodiment, in addition to the effects in the first embodiment, the following effects can be obtained. In the case of such a fan built-in type, as long as the outer shape of the fuel cell stack 15 having the same area is maintained, it is necessary to reduce the number of fuel cells 11 that can be mounted, but in the structure in which the fan unit 16 protrudes to the outside. Further, since the rectifying space 28 can be confined in the fuel cell stack portion 18, the structure can be simplified as a whole.

  Moreover, the air volume loss of the fan 51 and the airflow space 29 itself by passing through the rectifying space 28 can be shortened. Even if the power consumption is smaller, an air flow sufficient for power generation can be formed. In that case, the density of the fuel cells 11 can be improved by installing a fan 51 having the same size as that of the fuel cells 11.

  As described above, as in the fuel cell system 1 of the present invention, the upper surface and the side surface are closed by the casing 14, and the air flow from the stack intake opening 24 to the stack exhaust opening 25 is converted into a low-power consumption thin-diameter flow. In a structure in which a fan 51 such as a fan is used to supply the cathode 31, the fan 51 is surrounded by a fan cover 52, and an intake port 53 and an exhaust port 54 are provided in parallel or non-parallel to the fan cover 52. By connecting the air flow space 28 partitioned by the partition 26 via the rectifying plate 27, it becomes possible to supply sufficient air for power generation to all the fuel cells 11 constituting the fuel cell stack 15.

  Further, by devising the position of the opening of the fan cover 52, the rectifying space 28 that needs to be provided between the fan 51 and the fuel cell stack 15 can be minimized. Further, by combining the partition 26 and the guide plate 27, it is possible to incorporate a fan in the fuel cell stack unit 18.

  According to the present invention, a high-power thin fuel cell system that can be mounted on a portable device such as a PC can be realized, and the shape of the fuel cell stack 15 can also be changed to a mode different from the conventional one.

  In the first to fifth embodiments described above, the fan 51 is arranged so as to intake air from the fuel cell stack unit 18. However, the fan 51 is placed with the positions in the intake direction and the exhaust direction reversed. By disposing, the fan 51 may send gas to the fuel cell stack unit 18 side. As described above, it is obvious that even if the air flow is arranged to be discharged from the fan 51 to the fuel cell stack unit 18 side, the same actions and effects as those in the first to fifth embodiments can be obtained.

  Hereinafter, the fuel cell system of the present invention will be specifically described by showing examples.

Example 1
The structure of the fuel cell used in Example 1 will be described below. First, catalyst-supported carbon fine particles were prepared by supporting 50% by weight of platinum fine particles having a particle diameter in the range of 3 to 5 nm on carbon particles (Ketjen Black EC600JD manufactured by Lion Corporation). To 1 g, a 5 wt% Nafion solution (trade name; DE521, “Nafion” is a registered trademark of DuPont) manufactured by DuPont was added and stirred to obtain a catalyst paste for cathode formation. This catalyst paste was applied at a coating amount of 1 to 8 mg / cm ² on carbon paper (TGP-H-120 manufactured by Toray Industries, Inc.) as a base material and dried to prepare a cathode 31 of 4 cm × 4 cm. . On the other hand, the catalyst paste for forming the cathode described above was used except that platinum (Pt) -ruthenium (Ru) alloy fine particles (Ru ratio was 50 at%) having a particle diameter in the range of 3 to 5 nm were used instead of the platinum fine particles. A catalyst paste for forming an anode was obtained under the same conditions as obtained. An anode 32 was produced under the same conditions as those for the cathode except that this catalyst paste was used.

  Next, an 8 cm × 8 cm × 180 μm-thick membrane made of Nafion 117 (number average molecular weight is 250,000) manufactured by DuPont is used as the solid polymer electrolyte membrane 33, and the cathode 31 is placed on one side in the thickness direction of the membrane. The carbon paper was arranged in the direction to be on the outside, and the anode 32 was arranged on the other surface in the direction in which the carbon paper was on the outside, and hot-pressed from the outside of each carbon paper. As a result, the cathode 31 and the anode 32 were joined to the solid polymer electrolyte membrane 33, and an MEA (electrode-electrolyte membrane assembly) 13 was obtained.

Next, on the cathode 31 and the anode 32, current collectors 41 and 42 made of a rectangular frame-shaped frame plate having an outer size of 6 × 6 cm ² made of stainless steel (SUS316), a thickness of 1 mm, and a width of 11 mm were arranged. . A seal member 43 made of a rectangular frame plate made of silicon rubber and having an outer dimension of 6 × 6 cm ² , a thickness of 0.3 mm, and a width of 10 mm is provided between the solid polymer electrolyte membrane 33 and the anode current collector. Arranged. Further, as a sealing member between the solid polymer electrolyte 33 and the cathode current collector 41, a rectangular frame-shaped frame plate made of silicon rubber having an outer dimension of 6 × 6 cm ² , a thickness of 0.3 mm, and a width of 10 mm is used. A sealing member 43 made of The solid polymer electrolyte membrane 33 protruding outside the current collector was cut.

  The frame 10 constituting the fuel cell system 1 is made of PP (polypropylene) having an outer dimension of 19 cm × 19 cm × thickness of 1 cm, and the fuel cells 11 are arranged in 3 columns × 3 rows inside the frame 10. Nine fuel tank portions 12 were formed so that they could be arranged (FIG. 1). The fuel is supplied from the stack fuel inlet 21 and flows between the fuel cells 11 connected by the fuel path 23 as shown in FIG. The fuel tank portion 12 is a container having an inner dimension of 4 × 4 cm and a depth of 5 mm, and a wicking material 60 made of a urethane material is contained therein as a fuel holding material.

  The MEA 13, the cathode current collector 41, the anode current collector 42, and the seal member 43 were integrated by screwing with a predetermined number of screws to obtain the fuel cell 11 according to Example 1.

  Nine fuel battery cells 11 thus prepared were prepared, arranged side by side on the frame 10 having the fuel flow path structure shown in FIG. Electrically, they were connected in series via current collectors of adjacent fuel cells 11. In FIG. 1, the minus terminal was taken out from the fuel cell located at the lower left, and the plus terminal was taken out from the fuel cell located at the lower right. Further, two fuel cell stacks 15 were prepared and placed side by side as shown in FIG. 5, one positive terminal was connected to the other negative terminal, and 18 fuel cell cells 11 were connected in series.

  The two fuel cell stacks 15 formed as described above are placed on an acrylic plate having a thickness of 2 cm, a depth of 30 cm, and a width of 40 cm. The upper surface of the fuel cell stack 15 has protrusions of 3 mm at both ends, and has a thickness. An air flow space 29 as shown in the cross section of FIG. 5 was formed on an acrylic member having a size of 1 cm × depth 19 cm × width 38 cm. The stack intake opening portion 24 and the stack exhaust opening portion 25 are opened so that obstacles such as wiring do not block the air flow space 29. On the back of the stack exhaust opening 25, a pair of rectifying plates 17 having a height of 1.5 cm processed with an acrylic material is formed so that a rectifying space 28 having a maximum depth of 5 cm as shown in FIG. 5 is formed. It was installed and joined to a member laid on the bottom of the fuel cell stack 15. A part of the rectifying wall 17 that forms the back surface of the rectifying space 28 is cut to have an internal dimension of 1.3 cm in height × 5.5 cm in depth × 5.2 cm in width, and an intake port 53 and an exhaust port 54 are provided in parallel. The fan 51 surrounded by the fan cover 52 was installed as shown in FIG. The fan cover 51 was made of an acrylic resin. As the fan 51, a small motor fan with power consumption of 1 W was used. The distance between the fan 51 and the fuel cell stack 15 was set to be 5 cm at the shortest.

(Example 2)
The structure of the fuel cell used in Example 2 will be described below. The manufacturing method and structure of the MEA are the same as in Example 1. In addition, the fuel flow path structure is the same as that of the first embodiment (FIG. 1). Further, the fan 51 and the fan cover 52 are the same as those in the first embodiment. Other conditions are the same unless otherwise mentioned later.

  For Example 2, eight urethane materials having a thickness of 3 mm and a thickness of 3 mm cut to a width of 3 mm and a length of 19 cm were prepared, and waterproof double-sided tape was affixed to both sides thereof, as shown in FIG. The partition 26 was affixed between the body 14 and the fuel cell stack 15.

(Example 3)
The structure of the fuel cell used in Example 3 will be described below. The manufacturing method and structure of the MEA are the same as in Example 1. In addition, the fuel flow path structure is the same as that of the first embodiment (FIG. 1). Further, the fan 51 and the fan cover 52 are the same as those in the first embodiment. The configuration of the partition 26 is the same as that of the second embodiment. Other conditions are the same unless otherwise mentioned later.

  Regarding Example 3, the distance between the fan 51 and the fuel cell stack 15 was reduced to 2 cm, and a urethane material having a thickness of 0.5 mm and a height of 1.3 cm and having no water absorption was used as the guide plate 27. As shown in FIG. 8, one end of the guide plate was connected to the partition 26 and the other end was connected to the air inlet 53. With respect to the intake port 53, five are assigned by the end portion of the guide plate 27, and the five assignments are 0.75 cm, 0.5 cm, 1.0 cm, 0.5 cm, and 0.75 cm in order from the left. did.

Example 4
The structure of the fuel cell used in Example 4 will be described below. The manufacturing method and structure of the MEA are the same as in Example 1. In addition, the fuel flow path structure is the same as that of the first embodiment (FIG. 1). The configuration of the partition 26 is the same as that of the second embodiment. Other conditions are the same unless otherwise mentioned later.

  In the fourth embodiment, the opening portion of the fan cover 52 is also provided on the side surface portion of the fan cover 52, and a part of the air inlet 53 is blocked. Specifically, as shown in FIG. 10, a fan side surface opening portion 531 having a depth of 2 cm was provided to block the central 2 cm portion of the air inlet 53. As shown in FIG. 9, the guide plate 27 is connected to the fan side surface opening portion 531. With respect to the fan side opening portion 531, the open portion of 1 cm at both ends, 0.75 cm at the second row from the end, and 0.25 cm at the center row is divided into each row by the end of the guide plate 27. Assigned. However, with respect to the central row, the open portion of the intake port 53 was assigned 1.5 cm each.

(Comparative Example 1)
The structure of the fuel cell used in Comparative Example 1 will be described below. The manufacturing method and structure of the MEA are the same as in Example 1. In addition, the fuel flow path structure is the same as that of the first embodiment (FIG. 1). Other conditions are the same unless otherwise mentioned later. In Comparative Example 1, the fan cover 52 was not provided on the fan 51. Other structures are the same as those in the first embodiment.

(Experimental result)
About Examples 1-4 and the comparative example 1, the following power generation tests were done. 1000 mL of 10 vol% methanol aqueous solution is circulated and supplied to each fuel cell stack 15 at a flow rate of 10 mL / min, and is 3 at a current value corresponding to a current density of 100 mA / cm ^{2 in} an atmospheric environment with an environmental temperature of 25 ° C. and a humidity of 50%. A time power generation test was conducted. Even if 3 hours did not elapse, power generation was stopped when the overall voltage became 5 V or less.

  FIG. 13 shows the power generation result. In Comparative Example 1, the voltage after 1 hour was 5.1V. In Comparative Example 1, since the air supply with good uniformity cannot be performed, nonuniformity occurs in the characteristics between the fuel cells, the voltage is low from the beginning, and after 5 hours or less after 1 hour, Was stopped. The air flow itself also has an effect of cooling the cathode 31 and the MEA 13, but in Comparative Example 1, the temperature increased at the MEA 13 where the air flow did not reach sufficiently, so the initial voltage seemed to be high, but for a long time The voltage decreased by generating electricity.

  In Example 1, since the direction of the airflow flowing through the airflow space 29 is directional, the voltage after 2 hours is 5.3 V, which is more stable than that in Comparative Example 1, but 2 hours Since it became 5V or less when it exceeded, power generation was stopped. Again, the voltage was high because the temperature of the MEA 13 was high in a portion where the air was not sufficiently supplied, but the voltage generated by the flooding was small because the water produced at the cathode 31 was less effective to be released on the air flow. Went down.

  In Example 2, the voltage after 2 hours was 5.1V. That is, compared with Comparative Example 1, the voltage could be maintained for a long time. However, since the air supply was relatively decreased at both ends of the row and the temperature increased, the voltage was high at 0.5 hours, but eventually flooding occurred at the ends of the row. The voltage dropped.

  In Example 3, the voltage after 3 hours was 6.3V. That is, stable power generation could be continued as compared with Comparative Example 1 and Examples 1 and 2. Due to the presence of the guide plate 27, air supply was sufficient even at both ends, and no flooding occurred.

  In Example 4, the voltage after 3 hours was 6.2V. That is, the result was almost the same as in Example 3, and stable power generation could be continued as compared with Comparative Example 1 and Examples 1 and 2. That is, stable power generation could be continued even though the distance between the fan 51 and the fuel cell stack 15 could be minimized.

  As described above, when the methods of the present invention shown in Examples 1 to 4, particularly Examples 3 and 4, are used, each fuel cell 11 of a planar stack type fuel cell having a plurality of rows is sufficient for power generation. Air supply is performed, and stable power generation is possible for a long time. In particular, since the rectifying space 28 can be minimized as in the fourth embodiment, it is advantageous for mounting a fuel cell on a portable device such as a PC that requires a relatively high output.

It is the schematic of a fuel cell stack. It is sectional drawing of the fuel cell stack in A-A 'of FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic of the fuel cell system of the type which blows with a fan, and the lower part in the figure is sectional drawing in B-B '. It is the perspective view which looked at the fan 51 from (A) top view, (B) side view, (C) diagonally back, and D) diagonally forward. 1 is a schematic view of a fuel cell system according to a first embodiment. It is the (A) top view and (B) side view of the fan unit in 1st Embodiment, (C) diagonally back, and (D) the perspective view seen from diagonally forward. It is the schematic of the fuel cell system which concerns on 2nd Embodiment. It is the schematic of the fuel cell system which concerns on 3rd Embodiment. It is the schematic of the fuel cell system which concerns on 4th Embodiment. It is the (A) top view and (B) side view of the fan unit in 4th Embodiment, (C) diagonally rear, (D) the perspective view seen from diagonally forward. It is the schematic of the fuel cell system which concerns on 5th Embodiment. It is the perspective view seen from the (A) top view and (B) side view of the fan unit in 5th Embodiment, (C) diagonally back, and (D) diagonally forward. It is an experimental result of Examples 1-4 and the comparative example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 10 Frame 11 Fuel cell 12 Fuel tank part 13 MEA
DESCRIPTION OF SYMBOLS 14 Case 15 Fuel cell stack 16 Fan unit 17 Current plate 18 Fuel cell stack part 21 Stack fuel inlet 22 Stack fuel outlet 23 Fuel path 24 Stack intake opening part 25 Stack exhaust opening part 26 Partition 27 Guide plate 28 Commutation space 29 Air flow Space 31 Cathode 32 Anode 33 Electrolyte membrane 41 Cathode current collector 42 Anode current collector 43 Seal member 45 Screw hole 51 Fan 511 Fan housing 52 Fan cover 53 Intake port 531 Fan cover side opening 54 Exhaust port 55 Fan intake port 56 Fan exhaust 57 Shielding plate 60 Wicking material

Claims (12)

A plurality of fuel cells having a structure in which an electrolyte membrane is sandwiched between an anode and a cathode, a fuel cell stack portion disposed on the same plane, and
A casing that covers at least one surface of the fuel cell stack part via an airflow space;
A single fan arranged in a planar direction of the fuel cell stack part;
A fan cover covering all directions of the fan;
Comprising
The air flow space is provided over the entire surface of the one side of the fuel cell stack part,
The housing communicates with the outside through an intake opening that is opened to introduce gas, and to the outside through an exhaust opening that is opened to discharge gas. Arranged to communicate,
The fan is disposed so as to be parallel to the planar direction of the fuel cell stack,
The said fan cover is a fuel cell system which has the inlet provided in the said fuel cell stack part side, and the exhaust port provided in the opposite side to the said fuel cell stack part side. The fuel cell system according to claim 1,
Furthermore,
A partition that divides the air flow space into a plurality of regions in the plane of the fuel cell stack part;
Comprising
The fan generates an airflow that flows from the intake opening to the exhaust opening through the airflow space,
The partition is connected to the intake opening part so as to divide the opening surface of the intake opening part at one end, and is connected to the exhaust opening part so as to divide the opening surface of the exhaust opening part at the other end. Fuel cell system. The fuel cell system according to claim 1 or 2, wherein
Furthermore,
A pair of rectifying plates disposed so as to surround a space between the exhaust opening and the intake port to form a rectifying space;
At least one guide plate disposed in a rectifying space surrounded by the pair of rectifying plates;
Comprising
The guide plate is provided to divide the rectifying space into a plurality of spaces,
The guide plate is connected to the intake port so as to divide the opening surface of the intake port at one end, and is connected to the exhaust opening portion so as to divide the open surface of the exhaust opening portion at the other end. Battery system. A fuel cell system according to claim 3, wherein
The guide plate is a fuel cell system connected at one end to the end of the partition. A fuel cell system according to any one of claims 1 to 4, wherein
In the fuel cell stack portion, a plurality of fuel cells are arranged in a lattice pattern,
The fuel cell stack unit is a fuel cell system in which the plurality of fuel cells are arranged in a rectangular shape as a whole. The fuel cell system according to claim 5, wherein
The fuel cell system, wherein a width of the intake port in a planar direction is smaller than a width of the exhaust opening portion. The fuel cell system according to claim 6, wherein
The fan cover has an intake surface facing the fuel cell stack portion, and an orthogonal surface orthogonal to the intake surface and also orthogonal to the plane of the fuel cell stack portion,
The fuel cell system, wherein the intake port is provided in at least a part of the intake surface and at least a part of the orthogonal surface. The fuel cell system according to claim 7, wherein
The fan cover is a fuel cell system arranged so as to contact the exhaust opening. A fuel cell system according to any one of claims 1 to 5,
In the fuel cell stack portion, the plurality of fuel cells are arranged to form a recess in a planar direction,
The fuel cell system, wherein the fan and the fan cover are disposed in the recess. A plurality of fuel cells having a structure in which an electrolyte membrane is sandwiched between an anode and a cathode, a fuel cell stack portion disposed on the same plane, and
A housing that covers at least one surface of the fuel cell stack portion by providing an air flow space between the cathode and the cathode; and
A single fan arranged in a planar direction of the fuel cell stack part;
A fan cover covering all directions of the fan;
Comprising
The housing is arranged such that the airflow space has an intake opening portion opened to introduce gas and an exhaust opening portion opened to discharge gas.
The fan is disposed so as to be parallel to the planar direction of the fuel cell stack,
The said fan cover is a fuel cell system which has the exhaust port provided in the said fuel cell stack part side, and the inlet port provided in the opposite side to the said fuel cell stack part side. A fuel cell system according to any one of claims 1 to 10,
The partition is a fuel cell system formed of a water-absorbing material having water absorption. The fuel cell system according to any one of claims 1 to 11, wherein
The guide plate is a fuel cell system formed of a water-absorbing material having water absorption.

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