JP2015056296A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heating efficiency of an end cell with a simple structure.SOLUTION: A fuel cell comprises: a laminate having a plurality of single cells; a cooling medium supply manifold which is arranged to extend along a lamination direction inside the laminate so as to supply a cooling medium to each of the single cells; a cooling medium discharge manifold which is arranged to extend along the lamination direction inside the laminate so as to discharge, to the outside of the laminate, the cooling medium discharged from each of the single cells; a pair of terminals which are arranged, outside two end cells disposed at both ends of the laminate, such that they make contact with the respective end cells; and a heat radiation part which comes into contact with one of the pair of terminals that is farthermost from an inlet of the cooling medium supply manifold or farthermost from an outlet of the cooling medium discharge manifold, and which is arranged inside the cooling medium supply manifold.

Description

  The present invention relates to a fuel cell.

  Conventionally, a fuel cell in which a plurality of single cells each including a membrane electrode assembly (hereinafter referred to as “MEA” (Membrane-Electrode Assembly)) and two separators sandwiching the MEA has been used. In such a fuel cell, two single cells (hereinafter referred to as “end cells”) located at both ends are in contact with terminals (current collector plates) on the outside, unlike other single cells. . End cells are susceptible to the external environment. In particular, when the outside air is at a low temperature, the end cell located on the outermost side of the fuel cell (cell stack) generates electric power without the reaction gas spreading due to freezing or clogging of water existing inside the end cell. It becomes a difficult situation. Therefore, a technique has been proposed in which a heater is disposed outside the terminal and the end cell is heated via the terminal using the heater (see, for example, Patent Document 1).

JP 2004-327065 A

  According to the technology for heating the end cells using the heater described above, there are problems that the manufacturing cost of the fuel cell is increased and that the fuel cell is enlarged. These problems are caused by the fact that one separator is arranged between the MEA and the separator functions as an anode separator of a single cell including one MEA and the cathode side of the single cell including the other MEA. This may occur in a fuel cell configured to function as a separator. Further, in the conventional fuel cell, improvement of the production efficiency of the fuel cell, cost reduction, power saving, easy production and the like have been desired.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

  According to one aspect of the invention, a fuel cell is provided. The fuel cell includes: a stacked body having a plurality of stacked single cells; and extending in the stacking direction inside the stacked body for supplying a cooling medium to the single cells included in the stacked body. A cooling medium supply manifold; cooling for discharging the cooling medium, which extends along the stacking direction inside the stacked body and is discharged from each single cell included in the stacked body, to the outside of the stacked body A medium discharge manifold; a pair of terminals disposed in contact with the end cells on the outside of the two end cells that are the two single cells located at both ends of the laminate; and the pair of terminals The cooling medium supply manifold is in contact with the terminal farthest from the inlet of the cooling medium supply manifold or the farthest from the outlet of the cooling medium discharge manifold. A heat radiating portion which is disposed inside the hold; comprises. According to the fuel cell of this embodiment, since the heat radiating portion in contact with the terminal is arranged inside the cooling medium supply manifold, the Joule heat accompanying the current collection at the terminal is released from the heat radiating portion, thereby The cooling medium can be warmed. For this reason, since the heated cooling medium can be supplied to the end cell in contact with the terminal, the end cell can be heated. Thus, since the whole end cell can be heated by warming the cooling medium before being supplied to the end cell, the heating efficiency of the end cell can be improved. In addition, since the end cell can be heated by providing the heat dissipating part, the configuration for heating the end cell can be simplified, and the fuel cell can be miniaturized. In addition, since the heat dissipating part is placed in contact with the terminal located farther from the outlet of the cooling medium discharge manifold among the pair of terminals, heating is performed using the high-temperature cooling medium discharged from the outlet of the cooling medium discharge manifold. The terminal that can not be heated.

  In addition, this invention can be implement | achieved in various aspects, for example, can be implement | achieved with forms, such as a fuel cell system, the manufacturing method of a fuel cell, the temperature adjustment method of a fuel cell.

It is explanatory drawing which shows schematic structure of the fuel cell as one Embodiment of this invention. It is a perspective view which shows the detailed structure of the 1st terminal 20 shown in FIG.

A. Embodiment:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell as one embodiment of the present invention. The fuel cell 100 includes a stacked body 11, a first terminal 20, a second terminal 30, and a cooling medium flow path forming member 40. In FIG. 1, the −Y direction coincides with the gravity direction (vertically below). Moreover, the thick solid line arrow in FIG. 1 indicates the flow of the cooling medium.

  The fuel cell 100 is a so-called polymer electrolyte fuel cell, and constitutes a fuel cell system together with a reaction gas (fuel gas and oxidant gas) supply unit, a cooling medium supply unit, and the like. Such a fuel cell system is mounted and used in an electric vehicle or the like as a system for supplying driving power, for example. In the present embodiment, cooling water (pure water) is used as the cooling medium. However, any medium having thermal conductivity such as antifreeze or air may be employed instead of the cooling water.

  The stacked body 11 includes a large number of single cells 10 stacked along the X-axis direction (+ X direction and −X direction). In other words, the stacked body 11 includes a large number of single cells 10 connected in series. The single cell 10 includes an MEA (not shown) and two separators (not shown) that sandwich the MEA. The MEA includes an electrolyte membrane, two catalyst layers that sandwich both surfaces of the electrolyte membrane, and two gas diffusion layers that sandwich the electrolyte membrane and the two catalyst layers. In this embodiment, the electrolyte membrane is a fluororesin ion exchange membrane containing a sulfonic acid group. The electrolyte membrane is not limited to a sulfonic acid group, and a membrane containing another ion exchange group such as a phosphoric acid group or a carboxylic acid group can be used. The catalyst layer is formed of a base material (catalyst support) in which a catalyst such as platinum or a platinum alloy is supported on a conductive carrier (for example, carbon particles). The gas diffusion layer is formed of a porous member. As the porous member, for example, a carbon porous body such as carbon paper, or a metal porous body such as a metal mesh or a foam metal can be used. The separator is formed of a gas impermeable conductive member. As such a member, for example, dense carbon that has been made to be gas-impermeable by compressing carbon, or a press-molded metal plate can be employed. A reaction gas flow path and a cooling medium flow path are formed inside the separator.

  The unit cells 10 (referred to as “end cells”) located at both ends of the stacked body 11 are in contact with the terminals on the side opposite to the side in contact with the unit cell 10. Specifically, the first end cell 10 e is in contact with the first terminal 20 on the side opposite to the adjacent single cell 10. The second end cell 10 f is in contact with the second terminal 30 on the side opposite to the side in contact with the single cell 10.

  Inside the stacked body 11, a cooling medium supply manifold 51 and a cooling medium discharge manifold 52 are formed. The cooling medium supply manifold 51 and the cooling medium discharge manifold 52 both extend along the stacking direction (X-axis direction) of the stacked body 11. The cooling medium supply manifold 51 supplies the cooling medium supplied to the stacked body 11 to each single cell 10. The cooling medium discharge manifold 52 discharges the cooling medium discharged from each single cell 10 to the outside of the stacked body 11. The cooling medium supply manifold 51 is formed by connecting through holes in the thickness direction provided at the same position in each unit cell 10 in the stacking direction. The cooling medium discharge manifold 52 is configured in the same manner as the cooling medium supply manifold 51.

  The first terminal 20 and the second terminal 30 are both plate-like members formed of a gas-impermeable conductive member, like the separator. The first terminal 20 and the second terminal 30 are so-called current collecting plates and take out current from the stacked body 11. The first terminal 20 is disposed outside the first end cell 10e and in contact with the first end cell 10e. The second terminal 30 is disposed outside the second end cell 10f and in contact with the second end cell 10f.

  FIG. 2 is a perspective view showing a detailed configuration of the first terminal 20 shown in FIG. A thick solid line arrow in FIG. 2 indicates the flow of the cooling medium. As shown in FIG. 2, the first terminal 20 is a terminal farthest from the inlet of the cooling medium supply manifold 51 and farthest from the outlet of the cooling medium supply manifold 51 among the two terminals 20 and 30. As shown in FIG. 2, the first terminal 20 includes a fin 22 and a current extraction unit 25. The fins 22 release the heat of the first terminal 20 to the outside. The fin 22 has a thin plate-like appearance in order to improve the heat dissipation efficiency. In the present embodiment, the fin 22 is formed of a member different from the thin plate member that constitutes the main body of the first terminal 20, and is joined to the main body of the first terminal 20. In addition, it can replace with this structure and the fin 22 and the main body of the 1st terminal 20 can also be formed as an integral member. In the example of FIGS. 1 and 2, the number of fins 22 is three, but is not limited to three and may be an arbitrary number. The fins 22 are disposed so as to protrude in the thickness direction (−X direction) of the first terminal 20 on the surface in contact with the first end cell 10 e in the first terminal 20. Further, as shown in FIG. 1, the fins 22 are arranged in the vicinity of the inlet of the cooling medium in the first end cell 10e and the inlet of the cell 10 adjacent to the first end cell 10e in the cooling medium supply manifold 51. It is arranged to be located in and. In addition, since the fins 22 are in direct contact with the cooling medium, the fins 22 may be corroded by the cooling medium. Therefore, in order to suppress such corrosion, the surface of the fin 22 may be covered with a member that conducts heat and hardly corrodes.

  The current extraction portion 25 is formed as a part of the first terminal 20 and protrudes in the + Y direction as compared with other portions of the first terminal 20. The current extraction unit 25 functions as a terminal and is connected to a cable (not shown). The heat distribution in the first terminal 20 when the fuel cell 100 is in the power generation state is such that the heat generation amount becomes higher as it is closer to the current extraction unit 25. This is because the current collected in the first terminal 20 as a whole is concentrated in the current extraction unit 25, so that the Joule heat generated in the current extraction unit 25 is higher than the Joule heat generated in other portions.

  The configuration of the second terminal 30 is that the fin 22 is not provided, the current extraction unit 25 is provided instead of the current extraction unit 25, and the supply hole 31 and the discharge hole 32 shown in FIG. Unlike the configuration of the first terminal 20, the other configurations are the same as those of the first terminal 20.

  Similar to the current extraction unit 25 of the first terminal 20, the current extraction unit 35 is formed as a part of the second terminal 30, and protrudes in the + Y direction as compared with other parts of the second terminal 30. . The supply hole 31 is a through hole extending in the thickness direction (X-axis direction) of the second terminal 30 and communicates with the inlet 51 e of the cooling medium supply manifold 51. The discharge hole 32 is a through hole extending in the thickness direction (X-axis direction) of the second terminal 30 and communicates with the outlet 52 e of the cooling medium discharge manifold 52.

  The cooling medium flow path forming member 40 is in contact with the second terminal 30 on the surface opposite to the surface in contact with the second end cell 10 f of the second terminal 30. The cooling medium flow path forming member 40 guides the cooling medium supplied from the outside of the fuel cell 100 to the supply hole 31. Inside the cooling medium flow path forming member 40, a cooling medium supply flow path 41 and a cooling medium discharge flow path 42 are formed. The cooling medium supply channel 41 is a through hole extending in the thickness direction (X-axis direction) of the cooling medium channel forming member 40 and communicates with the supply hole 31 of the second terminal 30. A cooling medium supply pump (not shown) can be connected to the cooling medium supply channel 41.

  The cooling medium discharge channel 42 communicates with the discharge hole 32 and discharges the cooling medium discharged from the discharge hole 32 to the outside of the fuel cell 100. A part of the cooling medium discharge channel 42 is configured by a groove formed on the surface on the + X side of the cooling medium channel forming member 40 (a surface in contact with the second terminal 30), and the other part communicates with the groove. It is comprised as a through-hole. Therefore, the cooling medium discharge channel 42 is in contact with the second terminal 30 in the above-described groove. Since the cooling medium discharged from each single cell 10 has a high temperature, the second terminal 30 is heated when the high-temperature cooling medium passes through the cooling medium discharge channel 42 (groove in contact with the second terminal 30). Moreover, the 2nd terminal cell 10f which touches the 2nd terminal 30 is also heated by the 2nd terminal 30 being heated.

  As indicated by solid arrows in FIG. 1, the cooling medium supplied from the outside of the fuel cell 100 to the cooling medium supply channel 41 passes through the cooling medium supply channel 41, the supply hole 31, and the cooling medium supply manifold 51. And supplied to each single cell 10. Further, the cooling medium discharged from each single cell 10 is discharged to the outside of the fuel cell 100 through the cooling medium discharge manifold 52, the discharge hole 32, and the cooling medium discharge channel 42.

  As shown in FIG. 2, the cooling medium supply manifold 51 and the cooling medium discharge manifold 52 are arranged so as to be diagonal to each other on the end face of each single cell 10 (the face in contact with the adjacent single cell 10). ing. Since the cooling medium supply manifold 51 is positioned vertically upward (more in the + Y direction) than the cooling medium discharge manifold 52, the cooling medium supplied to each single cell 10 is more accurately Flows vertically downward in the separator of each single cell 10 and then discharged to the cooling medium discharge manifold 52.

  For example, when the fuel cell 100 is started in a low temperature environment such as below freezing point, a low temperature cooling medium is supplied to the fuel cell 100 (cooling medium supply manifold 51). However, since the fins 22 are disposed in the vicinity of the first end cells 10e in the cooling medium supply manifold 51, the first end cells 10e are separated from the fins 22 as shown in FIG. A cooling medium warmed by heat dissipation is supplied. Therefore, the first end cell 10e can be heated.

  In the fuel cell 100 described above, the fins 22 are arranged in the vicinity of the first end cells 10e inside the cooling medium supply manifold 51, so that Joule heat accompanying current collection in the first terminal 20 is released from the fins 22, With this heat dissipation, the cooling medium supplied to the first end cell 10e can be heated. Thus, since the cooling medium before being supplied to the first end cell 10e is heated in the cooling medium supply manifold 51, the heating efficiency of the first end cell 10e can be improved. In addition, since the first end cell 10e can be heated by providing the fins 22, the configuration for heating the first end cell 10e can be simplified, and the fuel cell 100 can be downsized.

  In addition, since the current extraction unit 25 is disposed at a position close to the cooling medium supply manifold 51, a large amount of heat can be transmitted to the cooling medium. Further, since the external shape of the functional part (fin 22) accommodated in the cooling medium supply manifold 51 in order to release the heat of the first terminal 20 is a thin plate shape, the surface area is increased to reduce the heat radiation amount. Can be big.

B. Variation:
B1. Modification 1:
In the embodiment described above, the cooling medium flow path forming member 40 is disposed in contact with the second terminal 30, but may be disposed in contact with the first terminal 20 instead of the second terminal 30. For example, the flow direction of the cooling medium in the cooling medium discharge manifold 52 is changed from the −X direction to the + X direction in the embodiment, and a cooling medium flowing through the cooling medium discharge manifold 52 is provided in the first terminal 20 (not shown). You may employ | adopt the structure guide | induced to the cooling medium flow path formation member 40 through a hole. In this configuration, the first end cell 10 e can be heated via the first terminal 20 using the cooling medium flowing through the cooling medium flow path forming member 40 as in the above-described embodiment. Therefore, in this configuration, the fins 22 may be omitted from the first end cell 10e. Further, in this configuration, it is preferable that fins are provided in the second terminal 30 and the fins are disposed in the vicinity of the second end cell 10 f in the cooling medium supply manifold 51. The terminal in contact with the cooling medium flow path forming member 40 can be heated using a high temperature cooling medium discharged from the stacked body of the single cells 10, whereas the terminal not in contact with the cooling medium flow path forming member 40 is This is because heating using such a high-temperature cooling medium cannot be performed. As can be understood from this modified example and the above-described embodiment, the cooling is performed at least on the terminal farthest from the outlet of the cooling medium discharge manifold 52 among the pair of terminals 20 and 30 arranged at both ends of the stacked body of the single cells 10. A configuration in which fins accommodated in the medium supply manifold 51 are provided can be applied to the present invention. In the fuel cell 100, the cooling medium flow path forming member 40 may be omitted. Even in such a configuration, at least the first end cell 10e out of the two end cells 10e and 10f can be heated using heat radiation from the fins 22.

B2. Modification 2:
In the embodiment described above, the single cell 10 is configured by an MEA (not shown) and two separators (not shown) that sandwich the MEA, but the present invention is not limited to this. For example, a single cell stack may have a structure in which MEAs and separators are alternately stacked, and each separator may be used as an anode separator and a cathode separator of two adjacent single cells. Good. In this configuration, a single cell is configured by the MEA and a part of each of the two separators sandwiching the MEA on the side in contact with the MEA.

B3. Modification 3:
In the embodiment described above, the appearance shape of the functional part (fin 22) accommodated inside the cooling medium supply manifold 51 for releasing the heat of the first terminal 20 is a thin plate shape, but is thin. Instead of the plate-like shape, any shape capable of radiating heat (having thermal conductivity) may be adopted. For example, you may employ | adopt many acicular external shapes extended in the -X direction. That is, in general, a heat radiating part having an arbitrary external shape and capable of radiating heat may be employed as the heat radiating part of the present invention.

B4. Modification 4:
In the above-described embodiment, a groove for circulating the cooling medium may be formed on the surface of the first terminal 20 in contact with the first end cell 10e. With such a configuration, since the cooling medium can be circulated between the first end cell 10e and the first terminal 20, the cooling medium heated at a position closer to the first terminal 20 can be used. The one end cell 10e can be heated, and the heating efficiency can be further improved.

B5. Modification 5:
In the embodiment described above, the fins 22 are positioned in the vicinity of the inlet of the cooling medium in the first end cell 10e and in the vicinity of the inlet of the cell 10 adjacent to the first end cell 10e inside the cooling medium supply manifold 51. However, the present invention is not limited to this. You may arrange | position the fin 22 so that it may be located in the vicinity of the inlet_port | entrance of each cooling medium in the arbitrary number of single cells 10 in the -X direction counting from the 1st end part cell 10e. In the cooling medium supply manifold 51, the single cells 10 are located only near the inlet of the cooling medium in the first end cell 10e, or several single cells 10 in the −X direction from the first end cell 10e. It is preferable to arrange the fins 22 so as to be positioned in the vicinity of the inlet of each cooling medium in FIG.

  The present invention is not limited to the above-described embodiments and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments and the modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Single cell 10e ... 1st edge part cell 10f ... 2nd edge part cell 11 ... Laminated body 20 ... 1st terminal 22 ... Fin 25 ... Current extraction part 30 ... 2nd terminal 31 ... Supply hole 32 ... Discharge hole 35 ... Current extraction unit 40 ... cooling medium flow path forming member 41 ... cooling medium supply flow path 42 ... cooling medium discharge flow path 51 ... cooling medium supply manifold 51e ... inlet 52 ... cooling medium discharge manifold 52e ... outlet 100 ... fuel cell

Claims (1)

A fuel cell,
A laminate having a plurality of laminated single cells;
A cooling medium supply manifold that extends in the stacking direction inside the stacked body and supplies a cooling medium to each single cell included in the stacked body;
A cooling medium discharge manifold that extends along the stacking direction inside the stacked body and discharges the cooling medium discharged from each single cell included in the stacked body to the outside of the stacked body;
A pair of terminals arranged in contact with the end cells on the outside of the two end cells that are the two single cells located at both ends of the laminate;
Of the pair of terminals, a heat dissipating part that is located farthest from the inlet of the cooling medium supply manifold or that is in contact with the terminal farthest from the outlet of the cooling medium discharge manifold, and is disposed inside the cooling medium supply manifold,
A fuel cell comprising:

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